Consulta: subjectFacets:"Simulation"
Registros recuperados: 202
Data/hora: 03/06/2024 16:18:27

Bioinformática : Aplicaciones a la proteómica y genómica
Provedor de dados: 32
Autores: Riaño Pachón, Diego Mauricio; González Estrada, Elizabeth; Alexa, Adrian; Ramírez, Fidel; Vischi Winck, Flavia; Gómez Merino, Fernando, Coord.; Silva Rojas, Hilda Victoria, Coord.; Pérez Rodríguez, Paulino, Coord.
En esta publicación intitulada “Bioinformática: aplicaciones a la genómica y proteómica” se detallan algunos de los avances más sobresalientes de los temas de genómica y proteómica, derivados de un curso internacional sobre el tema, organizado por el Colegio de Postgraduados. Estos avances incluyen aspectos de las dos ciencias ómicas, incluyendo genómica y biología estructural, código R, análisis comparativo y evolución, agrupamiento y minería de datos en R, redes de interacciones entre proteínas y proteómica bioinformática. BIOINFORMATICS : APPLICATIONS TO GENOMICS AND PROTEOMICS. ABSTRACT : In this publication entitled "Bioinformatics: applications to genomics and proteomics" are some of the most salient issues of genomics and proteomics, derived from an...
Tipo: Libro
Palavras-chave: Bioinformática; Proteómica; Genómica; ADN; Proteínas; Modelación; Simulación; Análisis de genómas; Biología estructural; Código R; Análisis comparativo; Minería de datos; Computación aplicada; Bioinformatics; Proteomics; DNA; Proteins; Models; Genomics; Simulation; R Code; Data mining; Computing; Genome analysis.
Ano: 2010
URL: http://hdl.handle.net/10521/313

El modelo de simulación hidrológica SWAT aplicado en la cuenca del río Amajac, Hidalgo, México
Provedor de dados: 32
Autores: Mata Espinosa, Héctor Armando.
El objetivo de ésta investigación fue realizar una simulación de la producción de agua en la cuenca del río Amajac, Hidalgo, México, mediante la aplicación del modelo hidrológico SWAT (Soil and Water Assessment Tool).  Previamente se realizó una calibración del modelo, ajustando sus parámetros más sensibles, tales como: curva numérica (CN2), capacidad de agua disponible en el suelo, factor de compensación de la evaporación en el suelo, y coeficiente de agua subterránea.  En la etapa de simulación se empleó el Sistema de Información Geográfica Arc View 3.2 y para alimentar el modelo, se utilizó la información climatológica proporcionada por el Servicio Meteorológico Nacional (SMN) para un periodo de cinco años (1996-2000), la información hidrométrica fue...
Tipo: Tesis
Palavras-chave: Simulación; Producción de agua; Modelo hidrológico; SWAT; Maestría; Hidrociencias; Simulation; Water yield; Hydrologic model; SWAT.
Ano: 2008
URL: http://hdl.handle.net/10521/1600

Seasonal Climate Variation and Caribou Availability: Modeling Sequential Movement Using Satellite-Relocation Data
Provedor de dados: 7
Autores: Nicolson, Craig; Department of Natural Resources Conservation, University of Massachusetts, Amherst ; craign@eco.umass.edu; Berman, Matthew; Institute of Social and Economic Research, University of Alaska Anchorage; matthew.berman@uaa.alaska.edu; West, Colin Thor; Department of Anthropology, University of North Carolina at Chapel Hill ; ctw@email.unc.edu; Kofinas, Gary P.; Department of Humans and Environment and Institute of Arctic Biology, University of Alaska, Fairbanks ; gpkofinas@alaska.edu; Griffith, Brad; U.S. Geological Survey Alaska Cooperative Fish and Wildlife Research Unit; Institute of Arctic Biology University of Alaska Fairbanks; dbgriffith@alaska.edu; Russell, Don; CircumArtic Rangifer Monitoring and Assessment Network (CARMA); don.russell@ec.gc.ca; Dugan, Darcy; Alaska Ocean Observing System; dugan@aoos.org.
Livelihood systems that depend on mobile resources must constantly adapt to change. For people living in permanent settlements, environmental changes that affect the distribution of a migratory species may reduce the availability of a primary food source, with the potential to destabilize the regional social-ecological system. Food security for Arctic indigenous peoples harvesting barren ground caribou (Rangifer tarandus granti) depends on movement patterns of migratory herds. Quantitative assessments of physical, ecological, and social effects on caribou distribution have proven difficult because of the significant interannual variability in seasonal caribou movement patterns. We developed and evaluated a modeling approach for simulating the distribution...
Tipo: Peer-Reviewed Reports
Palavras-chave: Caribou; Markovian; Migration; Rangifer tarandus granti; Seasonal distribution; Simulation; Subsistence hunting.
Ano: 2013

Improving Participatory Processes through Collective Simulation: Use of a Community of Practice
Provedor de dados: 7
Autores: Dionnet, Mathieu; Lisode; mathieu.dionnet@lisode.com; Daniell, Katherine A; Centre for Policy Innovation, The Australian National University; katherine.daniell@anu.edu.au; Imache, Amar; Lisode; amar.imache@lisode.com; von Korff, Yorck; Lisode; yorck.von-korff@lisode.com; Bouarfa, Sami; UMR G-EAU, Cemagref; sami.bouarfa@cemagref.fr; Garin, Patrice; UMR G-EAU, Cemagref; patrice.garin@cemagref.fr; Jamin, Jean-Yves; UMR G-EAU, CIRAD; jamin@cirad.fr; Rollin, Dominique; UMR G-EAU, Cemagref; dominique.rollin@cemagref.fr; Rougier, Jean-Emmanuel; Lisode; Jean-Emmanuel.Rougier@lisode.com.
Tipo: Peer-Reviewed Reports
Palavras-chave: Community of practice; Natural resource management; Public participation; Role play; Simulation.
Ano: 2013

A Fractal Landscape Realizer for Generating Synthetic Maps
Provedor de dados: 7
Autores: Hargrove, William; Oak Ridge National Laboratory; hnw@fire.esd.ornl.gov; Hoffman, Forrest M; Oak Ridge National Laboratory;; Schwartz, Paul M; ;.
A fractal landscape realizer has been developed that generates synthetic landscape maps to user specifications. The alternative landscape realizations are not identical to the actual maps after which they are patterned, but are similar statistically (i.e., the areas and fractal character of each category are replicated). A fractal or self-affine pattern generator is used to provide a spatial probability surface for each category in the synthetic map. The Fractal Realizer arbitrates contentions among categories in a way that makes it possible to preserve the fractal patterns of all the categories in the resulting synthetic landscape. Each synthetic landscape is one equally likely realization from among an infinite ensemble of possible fractal landscape...
Tipo: Peer-Reviewed Reports
Palavras-chave: FRAGSTATS; Fractal Realizer; Turing Test; Categorical maps; Fractal; Landscape ecology; Neutral model; Null model; Pattern; Pseudoreplication; Realization; Simulation; Synthetic map.
Ano: 2002

Modeling the Effects of Land Use on the Quality of Water, Air, Noise, and Habitat for a Five-County Region in Georgia
Provedor de dados: 7
Autores: Dale, Virginia H; ; dalevh@ornl.gov; Akhtar, Farhan; Georgia Institute of Technology;; Aldridge, Matthrew; University of Tennessee;; Baskaran, Latha; Oak Ridge National Laboratory;; Berry, Michael; University of Tennessee;; Browne, Murray; University of Tennessee;; Chang, Michael; Georgia Institute of Technology;; Efroymson, Rebecca; Oak Ridge National Laboratory;; Garten, Jr., Charles; Oak Ridge National Laboratory;; Lingerfelt, Eric; University of Tennessee;; Stewart, Catherine; Aberdeen Proving Ground;.
A computer simulation model, the Regional Simulator (RSim), was constructed to project how land-use changes affect the quality of water, air, noise, and habitat of species of special concern. RSim was designed to simulate these environmental impacts for five counties in Georgia that surround and include Fort Benning. The model combines existing data and modeling approaches to simulate the effects of land-cover changes on: nutrient export by hydrological unit; peak 8-h average ozone concentrations; noise caused by small arms and blasts; and habitat changes for the rare Red-cockaded Woodpecker (Picoides borealis) and gopher tortoise (Gopherus polyphemus). The model also includes submodules for urban growth, new urbanization influenced by existing roads,...
Tipo: Peer-Reviewed Reports
Palavras-chave: Gopher tortoise; Land use; Landscape change; Longleaf pine; Nutrient export; Red-cockaded Woodpecker; Simulation.
Ano: 2008

Challenges in adaptive management of riparian and coastal ecosystems
Provedor de dados: 7
Autores: Walters, Carl; University of British Columbia; c.walters@fisheries.ubc.ca.
Many case studies in adaptive-management planning for riparian ecosystems have failed to produce useful models for policy comparison or good experimental management plans for resolving key uncertainties. Modeling efforts have been plagued by difficulties in representation of cross-scale effects (from rapid hydrologic change to long-term ecological response), lack of data on key processes that are difficult to study, and confounding of factor effects in validation data. Experimental policies have been seen as too costly or risky, particularly in relation to monitoring costs and risk to sensitive species. Research and management stakeholders have shown deplorable self-interest, seeing adaptive-policy development as a threat to existing research programs and...
Tipo: Peer-Reviewed Reports
Palavras-chave: Adaptive management; Coastal ecosystems; Ecosystem management; Fisheries; Institutional barriers; Management experiments; Modeling; Riparian ecosystems; Simulation.
Ano: 1997

Managing the Resilience of Lakes: A Multi-agent Modeling Approach
Provedor de dados: 7
Autores: Janssen, Marco A; Indiana University; maajanss@indiana.edu; Carpenter, Stephen R; University of Wisconsin-Madison; srcarpen@wisc.edu.
We demonstrate an approach for integrating social and ecological models to study ecosystem management strategies. We focus on the management of lake eutrophication. A model has been developed in which the dynamics of the lake, the learning dynamics of society, and the interactions between ecology and society are included. Analyses with the model show that active learning is important to retain the resilience of lakes. Although very low levels of phosphorus in the water will not be reached, active learning reduce the chance of catastrophic high phosphorus levels.
Tipo: Peer-Reviewed Reports
Palavras-chave: Active learning; Eutrophication; Integrated modeling; Lake dynamics; Lake management; Multi-agent modeling; Phosphorus; Resilience; Restoration; Simulation.
Ano: 1999

Mechanisms Affecting Population Density in Fragmented Habitat
Provedor de dados: 7
Autores: Tischendorf, Lutz; ELUTIS Modelling and Consulting Inc.; lutz.tischendorf@gmx.net; Grez, Audrey; Universidad de Chile; agrez@uchile.cl; Fahrig, Lenore; Carleton University; lfahrig@ccs.carleton.ca.
We conducted a factorial simulation experiment to analyze the relative importance of movement pattern, boundary-crossing probability, and mortality in habitat and matrix on population density, and its dependency on habitat fragmentation, as well as inter-patch distance. We also examined how the initial response of a species to a fragmentation event may affect our observations of population density in post-fragmentation experiments. We found that the boundary-crossing probability from habitat to matrix, which partly determines the emigration rate, is the most important determinant for population density within habitat patches. The probability of crossing a boundary from matrix to habitat had a weaker, but positive, effect on population density. Movement...
Tipo: Peer-Reviewed Reports
Palavras-chave: Boundary crossing; Emigration; Habitat fragmentation; Immigration; Modeling; Movement; Population density; Simulation; Time scale.
Ano: 2005

Adaptive Harvesting in a Multiple-Species Coral-Reef Food Web
Provedor de dados: 7
Autores: Kramer, Daniel B; Michigan State University; dbk@msu.edu.
The utility of traditional bio-economic harvest models suffers from their dependence on two commonly used approaches. First, optimization is often assumed for harvester behavior despite system complexity and the often neglected costs associated with information gathering and deliberation. Second, ecosystem interactions are infrequently modeled despite a growing awareness that these interactions are important. This paper develops a simulation model to examine the consequences of harvesting at two trophic levels in a coral-reef food web. The model assumes adaptive rather than optimizing behavior among fishermen.  The consequences of changing economic, biological, and social parameters are examined using resilience as an evaluative framework. Three general...
Tipo: Peer-Reviewed Reports
Palavras-chave: Fisheries; Resource economics; Coral reefs; Resilience; Adaptive behavior; Food web; Simulation.
Ano: 2008

DEFORMATION OF PEACHES SUBMITTED TO CYCLIC LOADING USING THE DISCRETE ELEMENT METHOD
Provedor de dados: 70
Autores: Pinto,Eduardo M.; Ferraz,Antonio C. de O.
ABSTRACT This study aimed to use and validate a simple contact force model that describes the behavior of peaches stored in a wooden box, loaded cyclically, by using the discrete element method. The Kelvin-Voigt contact force model was used and the cyclic loading in the simulation was performed with an amplitude of 1 mm and frequency of 12 Hz for time intervals of 3600, 5400, and 7200 s. The laboratory test was performed with a peach box attached to a vibrating table by applying the same excitation conditions used in the simulation. For validation, model results were compared with those from the laboratory test by using deformation values of fruits in the contact regions. To measure this deformation, we adapted the methodology for determining the radius of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Modeling; Simulation; Post-harvest; Prunus persica (L.) Batsch.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000300434

Application of simulated annealing in simulation and optimization of drying process of Zea mays malt
Provedor de dados: 70
Autores: Benvenga,Marco A. C.; Araújo,Sidnei A. de; Librantz,André F. H.; Santana,José C. C.; Tambourgi,Elias B.
Kinetic simulation and drying process optimization of corn malt by Simulated Annealing (SA) for estimation of temperature and time parameters in order to preserve maximum amylase activity in the obtained product are presented here. Germinated corn seeds were dried at 54-76 °C in a convective dryer, with occasional measurement of moisture content and enzymatic activity. The experimental data obtained were submitted to modeling. Simulation and optimization of the drying process were made by using the SA method, a randomized improvement algorithm, analogous to the simulated annealing process. Results showed that seeds were best dried between 3h and 5h. Among the models used in this work, the kinetic model of water diffusion into corn seeds showed the best...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulated annealing; Zea mays; Drying curves; Optimization; Simulation.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000500012

Mechanical properties of grain in silos for simulation designs
Provedor de dados: 70
Autores: Lopes Neto,José P.; Nascimento,José W. B. do; Marques,Jordânio I.; Costa,Carlos A. da.
ABSTRACT For the calculation of silos structures it has been used new methods and computational tools that require mechanical properties knowledge that are still unknown for most storable materials, especially grains. In this context, we aimed to determine the mechanical properties of rice and beans grains with moisture contents of 10, 12, and 14% by applying four compressive loads (5, 10, 15 and 20). The determined mechanical properties were Poisson's ratio (ν), Modulus of Elasticity (E), and the dilatancy angle (ψ). The procedure consisted in the application of the load in compression cell, adapted from MOLENDA &amp; STASIAK, aiming to simulate loading and unloading of silos. We observed that the Poisson's ratio calculated for both loading and unloading,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Poisson’s coefficient; Compression; Modulus of elasticity; Silos; Simulation.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400573

NEURO-FUZZY MODELING OF EYEBALL AND CREST TEMPERATURES IN EGG-LAYING HENS
Provedor de dados: 70
Autores: Lins,Ana C. de S. S.; Lourençoni,Dian; Yanagi Júnior,Tadayuki; Miranda,Isadora B.; Santos,Italo E. dos A.
ABSTRACT Considering the challenges faced by poultry farming, this study aimed to develop a neuro-fuzzy model to predict eyeball and crest temperatures of egg-laying hens based on environmental conditions (dry bulb temperature and relative humidity). To develop the models and simulations, Matlab’s Fuzzy Toolbox® (Anfisedit) was used. Different configurations were used for each of the several neuro-fuzzy models developed. Eyeball temperature (ET) and chicken crest temperature (CCT) were simulated from the developed neuro-fuzzy models, and the obtained results were validated with the variables collected experimentally with the aid of recorder sensors and an infrared thermographic camera. The proposed neuro-fuzzy models allow the accurate estimation of ET and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Neuro-fuzzy; Thermography; Poultry farming; Simulation; Artificial intelligence.
Ano: 2021
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162021000100034

Computer tools applied to analysis of solar water heaters
Provedor de dados: 70
Autores: Altoé,Leandra; Oliveira Filho,Delly; Carlo,Joyce C.; Monteiro,Paulo Marcos de B.
The simulation programs are important tools to analyze the different energetic alternatives, including the use of renewable energy. The objective of this study was to analyze comparatively the different computer tools available for modeling of solar water heaters. Among the main simulation software of solar thermal systems, there are: RETScreen International, EnergyPlus, TRNSYS, SolDesigner, SolarPro, e T*SOL. Among the tools mentioned, only EnergyPlus and RETScreen International are free, but they allow obtaining interesting results when applied together. The first one has a detailed module of energy analysis of solar water heaters, while the second one provides an detailed economic feasibility study and an assessment of emissions of greenhouse gases....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Solar energy; Water heating.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000500018

CALIBRATION AND TESTING OF CS-CROPGRO MODEL FOR COMMON BEANS
Provedor de dados: 70
Autores: Santos,Miquéias G. Dos; Faria,Rogério T. De; Palaretti,Luiz F.; Dantas,Geffson De F.; Dalri,Alexandre B.; Lopes,Adriano Da S.
ABSTRACT: Simulation models of crop growth enable estimating crop yield and water balance components with low cost and high precision. This study aimed to calibrate and evaluate the performance of the CS-CROPGRO model for common beans under the conditions of Jaboticabal city (SP), Brazil. The model was calibrated and tested with data previously collected from two experiments conducted in 2002 and 2003. In these experiments, treatments corresponded to two irrigation scheduling methods (tensiometers and class A pan evaporation) and two cropping systems (conventional and no-till). For calibration, data from the experiment carried out in 2002 were used. For testing, we used data from the experiment conducted in 2003. By using the genetic coefficients...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; DSSAT; Phaseolus vulgaris; Irrigation; Planting system.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000601239

VALIDATION OF A HEATING SYSTEM IN THE FARROWING HOUSE USING A CFD APPROACH
Provedor de dados: 70
Autores: Damasceno,Flávio A.; Oliveira,Carlos E. A.; Saraz,Jairo A. O.; Schiassi,Leonardo; Oliveira,Jofran L. de.
ABSTRACT The current heating system for piglets in the farrowing usually uses incandescent lamps and, in some cases, heated floors with electric resistances, which in most cases generates a high energy cost. Thus, the implantation of systems that use renewable energies in the heating of piglets can allow the thermal comfort of the animals without reducing the productive development. The objective of this research was to evaluate a computer model in Computational Fluid Dynamics (CFD), which predicts surface temperature in the heating system of a farrowing house. The study was conducted during the summer season on the swine sector of Federal University of Lavras, Brazil. For this study, a prototype solar heater using alternative materials (ASWH) was...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Swine; Computational modelling; Simulation.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000400471

A DISCRETE STOCHASTIC MODEL TO DETERMINE FOOD QUALITY BY USING SIMULATION: A STRAWBERRY CASE STUDY
Provedor de dados: 70
Autores: González-Hernández,Isidro J.; Granillo-Macías,Rafael; Rondero-Guerrero,Carlos; Martínez-Flores,José L.
ABSTRACT The agri-food supply chain (AFSC) sets a series of challenges in the production, storage, distribution, and transportation processes, as the market's requirements for fresh food combine food quality and safety attributes. This research suggests a discrete event modeling to study the behavior of food quality in all supply chains (SCs) in terms of temperature and time variables in a stochastic manner. The ProModel software was used to simulate strawberry quality in the SC, considering a distribution route to export the fruit from Mexico to the United States. The suggested model together with a computer simulation analyzes the fruit quality from two perspectives: with and without a cold chain (CC). The obtained results revealed that in the case of CC...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agri-food supply chain; Discrete and stochastic model; Food quality; Simulation.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000600747

Effects of maintenance management procedures in sugarcane mechanic harvesting system equipment
Provedor de dados: 70
Autores: Faria,Luís F. F.; Silva,João E. A. R.
ABSTRACT The aim of this study was to evaluate the effects of modifying the maintenance programming of equipment used in sugarcane mechanical harvesting, by transferring actions that can be planned to periods when machines are inactive due to meal breaks and other working shift transitions stoppages. A simulation model was developed to represent the maintenance procedures of combines, haulouts, and other vehicles used by a harvest team. Scenarios were tested using alternatives for interventions such as refueling, lubrication and harvester blade replacement, enabling strategies to be focused towards better utilization of cutting, loading, and transport (CLT) system equipment. As a result, it was possible to remove one combine and two haulouts, while...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agricultural machinery; Breakdowns; Simulation.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162015000601187

Estimating the effects of population size and type on the accuracy of genetic maps
Provedor de dados: 74
Autores: Ferreira,Adésio; Silva,Marcia Flores da; Silva,Luciano da Costa e; Cruz,Cosme Damião.
Based on simulation studies, it was shown that the type and size of experimental populations can exert an influence on the accuracy of genetic maps. A hypothetical genome map (one chromosome with nine equidistant molecular markers) was generated for the following population types: F2 with dominant and co-dominant markers, backcrossing, recombinant inbred lines (RIL) and double-haploid. The population sizes were 50, 100, 150, 200, 500 and 1000 individuals and 100 simulations were made for each population. The inaccuracies of the populations with the lowest number of individuals were shown by inversions in the order of the markers and the establishment of more than one linkage group in up to 38% of the simulations, depending on the population type. Stress...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Experimental populations; Mapping; Simulation; Markers.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100033

Impacto bioeconômico da introdução de período de monta em sistemas de gado de corte no Brasil Central.
Provedor de dados: 14
Autores: ABREU, U. G. P. de; CEZAR, I. M.; TORRES, R. de A.
O cenário futuro da bovinocultura de corte indica claramente a necessidade de avanço dos sistemas de produção em direção da intensificação. Neste contexto, um dos primeiros passos para aumentar a eficiência no sistema de cria de bovinos de corte é a adoção do período de monta (PM), Entretanto, torna-se importante avaliar o impacto produtivo e econômico dessa tecnologia no sistema de produção como um todo. Os efeitos da implantanção de um PM são vários. Para essa análise, selecionaram-se os seguintes efeitos: (a) redução da taxa de mortalidade de bezerros de 10% para 4%; (b) redução touro: vaca de 1:25 para 1:33, isto é, de 4% para 3%; (c) aumento da taxa de natalidade das vacas de 65% para 75%; e (d) redução na mão-de-obra permanente de vaqueiros. Avaliar...
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Bovino de corte; Estação de monta; Aspecto econômico; Brasil Central; Breeding seasons; Farming sistems; Management; Simulation; Economic situation; Central Brazil.; Manejo; Reprodução; Simulação; Sistema de Produção.; Beef cattle; Reproduction.
Ano: 2002
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/325381

Suplementação alimentar de vacas de cria: quando e por que fazer?
Provedor de dados: 14
Autores: AMARAL, T. B.; CORRÊA, E. S.; COSTA, F. P.
Monitoramento do estado nutricional do rebanho. Suplementar antes ou após o parto? Categorias prioritárias a serem suplementadas. Recomendações para a suplementação. Simulação da suplementação estratégica em um sistema de produção.
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Bovino de corte; Suplementação; Supplements; Simulation; Brazilian savannas.; Análise Econômica; Cerrado; Nutrição Animal; Reprodução Animal; Vaca.; Simulação; Animal reproduction; Animal nutrition; Economic analysis.; Beef cattle; Cows.
Ano: 2005
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/316667

Modelos de simulação em pesquisa aplicada aos sistemas de produção na agropecuária.
Provedor de dados: 14
Autores: BROCKINGTON, N. R.; ZOCCAL, R.; VEIL, J. M.
Os modelos e exemplos de seu uso na pesquisa leiteira; Analises de pastagens alternativas na pecuária leiteira.
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Pesquisa aplicada; Simulation; Systems; Production; Simulação; Sistema de Produção; Agriculture; Research.
Ano: 1988
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/93883

Modelos de simulação e suas possíveis aplicações no estudo econômico do biodiesel.
Provedor de dados: 14
Autores: KINPARA, D. I.
This paper introduces the system simulation technique and looks for potential application in the biodiesel agribusiness. The simulation basics are presented. It's described the components of a simulation model, the models classification and the model construction process. Some uses in decision making and agricultural problems are shown. The decision making models search for possibilities while scientific models search for probabilities. The agricultural models have a high degree of uncertainty. In biodiesel agribusiness, this uncertainty is represented by its nationwide market, the long-run decision making, high investments and deep and diffuse social and environmental impacts. A simulation model study would be able to quantify the tradeoffs between the...
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Modelagem matemática; Agroenergia; Simulation; Agroenergy.; Desenvolvimento Rural; Simulação.; Biodiesel; Mathematical models; Rural development.
Ano: 2005
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/570355

Produção de carne de qualidade em pastagem: alternativas para o sistema físico da Embrapa Gado de Corte.
Provedor de dados: 14
Autores: CORRÊA, E. S.; COSTA, F. P.; CEZAR, I. M.; MACEDO, M. C. M.; EUCLIDES FILHO, K.; EUCLIDES, V. P. B.; ZIMMER, A. H.
A Embrapa Gado de Corte trabalha com modelos físicos de produção desde 1983. O último sistema implantado incluía a cria, recria e engorda de animais Nelore, sendo os machos suplementados em pasto na primeira seca e terminados em confinamento na segunda seca, com 24 meses de idade. Encerrada essa etapa, iniciou-se discussão para definir o novo sistema a implementar. Combinando duas taxas de lotação das pastagens (1,8 e 1,32 UA/ha) e diferentes estratégias de suplementação no período seco (ração concentrada e sal protéico), seis sistemas alternativos (e um sistema tradicional tomado como referência) foram então delineados e avaliados por meio de simulações com uma planilha eletrônica que permite projetar o desenvolvimento de uma fazenda em um horizonte de...
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Bovino de corte; Aspecto econômico; Simulation; Economic situation.; Modelo de Simulação; Sistema de Produção.; Beef cattle; Farming systems.
Ano: 2003
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/325800

Análise de investimento de programas de melhoramento de pastagem para a produção de gado de corte no Cerrado.
Provedor de dados: 14
Autores: MONTEIRO, L. A.; CHUDLEIGH, P. D.; GARDNER, A. L.
Descrição do modelo. Suposições referentes ao sistema tradicional. Estrutura do modelo. Dados. Validação. Programa de computador. Experimentação. Resultados e discussão. Proporção de pastagem melhorada na fazenda e idade de venda de macho. Taxa de estabelecimento da pastagem cultivada. Método para aumentar o numero de vacas de cria. Método para aumentar o tamanho do rebanho. Compra de vacas velhas para engordar durante a estação chuvosa. Prioridade para o uso da pastagem melhorada.
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Bovino de corte; Modelo; Aspecto econômico; Brasil; Sown pasture; Brazilian savannas; Production; Model; Simulation; Economic situation.; Cerrado; Pastagem Cultivada; Produção; Simulação.; Brazil; Beef cattle.
Ano: 1981
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/319643

Controlpec 1.0: controle financeiro simplificado para a fazenda de pecuária de corte.
Provedor de dados: 14
Autores: COSTA, F. P.; CORRÊA, E. S.
A maioria dos produtores de gado de corte não realiza adequadamente o controle de receitas e despesas de sua atividade. Como a lucratividade da pecuária de corte tem se reduzido pela queda no preço de seus produtos e pela alta nos custos de produção, tal função tornou-se crucial para aqueles que querem se manter no negócio. Para atender essa demanda, a Embrapa Gado de Corte desenvolveu, em ambiente Excel, o Controlpec 1.0, uma ferramenta simples e de fácil utilização pelos produtores. Com base no movimento financeiro da fazenda são gerados relatórios que consolidam despesas, receitas e margens econômicas da atividade, tendo em conta o plano de contas definido pelo usuário. Os resultados são expostos para cada mês do ano e para todo o ano.
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Bovino de corte; Controle; Brasil; Zootechny; Farm systems; Simulation; Control; Costs.; Administração Rural; Análise Econômica; Custo; Programa de Computador; Planejamento; Zootecnia.; Computer software; Economic analysis; Beef cattle; Farm management; Brazil; Planing.
Ano: 2006
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/326285

Aperfeicoamento e calibracao de aparelhos coletores de enxurrada para a medicao de perdas de solo, agua e nutrientes em estudos com simulador de chuva.
Provedor de dados: 14
Autores: RESCK, D. V. S.
bitstream/item/84019/1/bolpd-19.pdf
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E)
Palavras-chave: Calibracao; Medida; Simulation; Losses.; Água; Chuva; Conservação; Enxurrada; Equipamento; Manejo; Nutriente; Perda; Simulação; Solo.; Equipment; Rain; Measurement; Nutrients; Soil; Runoff; Water.
Ano: 1983
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/549445

Adaptação do modelo STICS ao balanço hídrico da sequência milho-milheto em sistema de plantio direto no cerrado brasileiro.
Provedor de dados: 14
Autores: SILVA, F. A. M. da; SCOPEL, E.; PINTO, H. S.; ASSAD, E. D.; CORBEELS, M.
bitstream/CPAC-2009/26890/1/p2005_66.pdf
Tipo: Fôlder / Folheto / Cartilha (INFOTECA-E)
Palavras-chave: Maize; Simulation; Growth.; Balanço Hídrico; Cerrado; Crescimento; Milho; Rendimento; Simulação; Zea Mays.; Crop yield; Water balance.
Ano: 2006
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/569497

Análise do uso de técnicas de aprendizado interativo e de suas possibilidades no contexto da pesquisa agropecuária e transferência de tecnologia.
Provedor de dados: 14
Autores: FONSECA, R. B.
bitstream/item/79552/1/doc-305.pdf
Tipo: Documentos (INFOTECA-E)
Palavras-chave: Jogo educativo; Educational game; Training; Simulation; Interactive learning.; Educação.; Education.
Ano: 2011
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/953445

Simulating the effect of regulatory systems in a fishery - An application to the French driftnet albacore fleet
Provedor de dados: 5
Autores: Guyader, Olivier.
With a thin economic component, most bio-economic models of fisheries fail to assess the effects of the regulation systems on firms. In order to analyse the short term consequences of different management schemes, a simulation model is applied to the French driftnet albacore fleet: licence allocation with driftnet regulation, individual quotas, and individual transferable quotas without any input control. Vessel technology is estimated by using the data collected, and groups of vessels are distinguished according to criteria of performance. We present the adjustment within firms and between groups under different scenarios (limited entry with and without driftnet regulation, individual quotas and individual transferable quotas allocation), and we compare...
Tipo: Text
Palavras-chave: Albacore tuna; Dolphin; Driftnet; Fisheries; ITQ; Licence; Quasi-rent; Quota price; Quotas; Regulation; Simulation.
Ano: 2002
URL: https://archimer.ifremer.fr/doc/00244/35523/34036.pdf

How to genetically increase fillet yield in fish: Relevant genetic parameters and methods to predict genetic gain
Provedor de dados: 5
Autores: Vandeputte, Marc; Fraslin, Clemence; Haffray, Pierrick; Bestin, Anastasia; Allal, Francois; Kocour, Martin; Prchal, Martin; Dupont-nivet, Mathilde.
Fillet yield (i.e. the proportion of edible muscle in a fish) is a key economic trait for species sold as fillets. Its genetic improvement is complicated by several of its characteristics 1) it is a ratio trait, 2) its numerator (fillet weight) and denominator (body weight) are strongly correlated (correlations in the range 0.89-0.99), 3) it offers little phenotypic variation and 4) it cannot be measured on alive breeding candidates. In a former study, we showed that it could be improved by selection, especially with three selection indices, fillet yield, residual fillet weight and a ratio-specific linear index. However, it is well known that the heritability of ratio traits does not permit a reliable prediction of genetic gains. As predictability of...
Tipo: Text
Palavras-chave: Aquaculture; Genetics; Heritability; Selection; Linear index; Residual fillet weight; Selection response; Simulation; Processing yields.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00612/72378/71390.pdf

Survey of stochastic models for wind and sea state time series
Provedor de dados: 5
Autores: Monbet, Valérie; Ailliot, P; Prevosto, Marc.
The knowledge of sea state and wind conditions is of central importance for many offshore and nearshore operations. In this paper, we make a complete survey of stochastic models for sea state and wind time series. We begin with methods based on Gaussian processes, then non-parametric resampling methods for time series are introduced followed by various parametric models. We also propose an original statistical method, based on Monte Carlo goodness-of-fit tests, for model validation and comparison and this method is illustrated on an example of multivariate sea state time series. (C) 2006 Elsevier Ltd. All rights reserved.
Tipo: Text
Palavras-chave: Model validation; Simulation; Nonlinear time series; Wind; Sea state.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2679.pdf

Understanding patterns and processes in models of trophic cascades
Provedor de dados: 5
Autores: Heath, Michael R.; Speirs, Douglas C.; Steele, John H.
Climate fluctuations and human exploitation are causing global changes in nutrient enrichment of terrestrial and aquatic ecosystems and declining abundances of apex predators. The resulting trophic cascades have had profound effects on food webs, leading to significant economic and societal consequences. However, the strength of cascades-that is the extent to which a disturbance is diminished as it propagates through a food web-varies widely between ecosystems, and there is no formal theory as to why this should be so. Some food chain models reproduce cascade effects seen in nature, but to what extent is this dependent on their formulation? We show that inclusion of processes represented mathematically as density-dependent regulation of either consumer...
Tipo: Text
Palavras-chave: Bottom-up; Density dependence; Food chain; Food web; Harvesting; Model; Predator-prey; Simulation; Top-down.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00171/28249/26505.pdf

Optimization of a survey using spatially balanced sampling: a single-year application of clam monitoring in the Arcachon Bay (SW France)
Provedor de dados: 5
Autores: Kermorvant, Claire; Caill-milly, Nathalie; D'Amico, Frank; Bru, Noelle; Sanchez, Florence; Lissardy, Muriel; Brown, Jennifer.
Bivalves are important components of benthic marine and freshwater ecosystems throughout the world. One of the most exploited bivalves used for human consumption is manila clam (Venerupis philippinarum). In Arcachon Bay (SW France), commercial fishers and scientists have developed a monitoring survey to estimate clam stocks to assist in implementing a sustainable management strategy. The survey design that is currently used is based on standard stratified random sampling (StRS). The survey has been undertaken every 2 years since 2006. Each survey costs approximately (sic) 50 000, with funding provided by similar to 20% of the commercial fishers. The survey is quite expensive, given that this resource is managed mostly at a regional level. In 2016 for...
Tipo: Text
Palavras-chave: Venerupis philippinarum; Bivalve; Simulation; Survey; Arcachon Bay; GRTS.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00410/52102/52808.pdf

Impact des mesures de gestion sur la dynamique de la pêcherie pélagique du golfe de Gascogne : Quelles certitudes ? Quels descripteurs ?
Provedor de dados: 5
Autores: Lehuta, Sigrid.
Quantitative evaluations of management measure impact on resource and fleet viability are required to provide diagnostics and feed decision process. Fisheries are complex systems where numerous dynamics interact at various spatial and temporal scales. This complexity and the difficulty to observe marine systems are responsible for the high uncertainty surrounding fishery functioning that makes it hard to identify adequate management measures. The increasing consideration of uncertainties in diagnostics argues in favor of robust management measures rather than optimal management measures. Identifying robust management measures requires the development of models that account for complexity and uncertainty in the description and prediction of management...
Tipo: Text
Palavras-chave: Modélisation; Pêcherie mixte; Gestion des pêcheries; Incertitudes; Simulation; Analyse de sensibilité; Indicateurs; Gestion spatialisée; ISIS-Fish; Modeling; Mixed fisheries; Fishery management; Uncertainty; Simulation; Sensitivity analysis; Indicators; Spatialised management; ISIS-Fish.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00025/13630/10712.pdf

Les pêcheries mixtes de langoustine et merlu du Golfe de Gascogne, modélisation bio-économique et simulation des procédures de gestion
Provedor de dados: 5
Autores: Charuau, Anatole.
Fishing crayfish on the gulf's mudflats is a traditional business practised by 450 boats of 12 to 18 metres in length and employs 2,500 sailors. In the north of the gulf, this activity is exclusive, in the south, immature hake are also caught, because the crayfish areas coincide, in part, with the nurseries of the northern stock of this species.   Management of these fisheries, called mixed, of crayfish and hake is one of the greatest problems of the Gulf of Gascony. All assessments tend to show the responsibility of the crayfish boats in the future of the hake stock. The solution is likely to pass through a generalised increase of the 80 mm meshing that would lead, eventually, the hake stock yield to its maximum, but would eliminate a great many trades...
Tipo: Text
Palavras-chave: Mixed fisheries; Bio economical modelisation; Bay of Biscay; Simulation; Prawn; Hake; Fishing fleet strategy; Fishing assessment; Pecherie mixre; Golfe de Gascogne; Modele bio economique; Simulation; Langoustine; Merlu; Stratégie des flottilles; Gestion des pêcheries.
Ano: 1988
URL: http://archimer.ifremer.fr/doc/1988/rapport-2569.pdf

Study of the manoeuvrability and security of a trawl gear
Provedor de dados: 5
Autores: Marichal, Dominique; Vincent, Benoit.
A complete method is presented for determining the static and dynamic behaviour of a fishing gear. The net, which is very flexible, is modelised by a set of rigid bars. The hydrodynamic forces, applied to each bar, are determined by combining and generalizing the Landweber and Morison hypothesis. A CFD method is used to calculate the forces on trawl doors. The fundamental principle of dynamics is completed with length equations expressing the elasticity of the bars. It leads to a set of second order non-linear differential equations, which is solved using a Runge-Kutta method. We will now present a few examples of the various applications of our works : the study of the trawl gear equilibrium in a uniform flow, an example of manoeuvrability (gyration of...
Tipo: Text
Palavras-chave: Runge Kutta; Elasticity; Simulation; Model; Trawl doors; Hydrodynamic; Fishing gear; Runge Kutta; Elasticite; Simulation; Modèle; Panneaux de chalut; Hydrodynamique; Engin de pêche.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-4612.pdf

Méthodologie pour une simulation des transformations granulométriques de sables de la zone d'avant-côte
Provedor de dados: 5
Autores: Barusseau, Jp; Diouf, Mb; De La Bardonnie, M; El Ghandour, N.
The grain-size of mature coastal sands changes rapidly in response to the variation of the energy regime which provokes either erosion or deposition of fractions of the textural assemblage. Whatever the dynamic conditions, questions of paramount importance such as the size of grain populations transported simultaneously, the most common size of the grains in movement and the grain-size range of the sediment fraction involved ape still poorly understood. The present paper deals with an attempt to describe this fraction without any consideration of the processes responsible for the observed changes. A major problem results from the fact that the distribution of the mobilized fraction cannot be known and described by direct comparison between the initial and...
Tipo: Text
Palavras-chave: Granulométrie; Fraction mobile; Modélisation; Simulation; Grain-size; Mobile fraction; Modelling; Simulation.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00325/43619/43919.pdf

Dynamical modelling of a reactive extrusion process: Focus on residence time distribution in a fully intermeshing co-rotating twin-screw extruder and application to an alginate extraction process
Provedor de dados: 5
Autores: Baron, Regis; Vauchel, Peggy; Kaas, Raymond; Arhaliass, Abdellah; Legrand, Jack.
The context of this study is the modelling of reactive extrusion process based on an alginate extraction protocol. Residence Time Distribution (RTD) is one important part to predict the kinetics of reactive compounds. A simple model is proposed to predict RTD in fully intermeshing co-rotating twin-screw extruders without reaction. This model, which can be easily extended to reactive case in a future work, is based on the extension of an axial dispersion model, including control parameters (screw speed and flow rate) and geometrical parameters (screw profile and die design). Simulations were performed for various operating and geometrical conditions so as to illustrate possibilities offered by the proposed model. Validation was conducted for two different...
Tipo: Text
Palavras-chave: Alginate; Extraction; Extrusion; Mathematical modelling; Residence time distribution; Simulation; Laminaria digitata.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00005/11592/8985.pdf

Coastal zones inventory by high resolution satellites
Provedor de dados: 5
Autores: Loubersac, Lionel.
The development of tools for assessing impacts on coastal environments is a reality. These impact assessments need both baseline and monitoring studies. Satellite remote sensing data would be useful for coastal inventories (baselines) and monitoring if high spatial and temporal resolutions are yield compatible. An overview of the various sensors that could be used is presented. The constraints linked to the different resolutions are exposed. An example based on Spot simulated data and trends are developed.
Tipo: Text
Palavras-chave: Milieu littoral; Télédétection; Méthode satellite; Haute résolution; Surveillance; Cartographie; Analyse composante principale; Simulation; Zone côtière; SPOT; Coastal environment; Remote sensing; Satellite methods; High-resolution methods; Monitoring; Cartography; Principal components analysis; Simulation.
Ano: 1983
URL: http://archimer.ifremer.fr/doc/00143/25379/23517.pdf

Estimating effective population size of large marine populations, is it feasible?
Provedor de dados: 5
Autores: Marandel, Florianne; Lorance, Pascal; Berthele, Olivier; Trenkel, Verena; Waples, Robin S.; Lamy, Jean-baptiste.
stainable exploitation of marine populations is a challenging task relying on information about their current and past abundance. Fisheries‐related data can be scarce and unreliable making them unsuitable for quantitative modelling. One fishery independent method that has attracted attention in this context consists in estimating the effective population size (Ne), a concept founded in population genetics. We reviewed recent empirical studies on Ne and carried out a simulation study to evaluate the feasibility of estimating Ne in large fish populations with the currently available methods. The detailed review of 26 studies found that published empirical Ne values were very similar despite differences in species and total population sizes (N). Genetic...
Tipo: Text
Palavras-chave: Census population size; Effective population size; Fish; Linkage disequilibrium; Management; Simulation.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00470/58162/60678.pdf

Modelling axisymmetric codends made of hexagonal mesh types
Provedor de dados: 5
Autores: Priour, Daniel.
Codends are the rear parts of trawls, which collect the catch and where most of the selectivity process occurs. Selectivity is the process by which the large sh are retained while the small ones are released. The codends applied in many sheries often consist of only one type of mesh. Therefore it is reason- able to consider these codends as being axisymmetric. Their shapes depend mainly on the volume of catch, on the shape of meshes (diamond, square, hexagonal) and on the number of meshes along and around the codend. The shape of the codends is of prime importance in order to understand the se- lectivity process. This paper presents a model of deformation of codends made up of hexagonal meshes. Two types of hexagonal meshes have been investigated: the T0...
Tipo: Text
Palavras-chave: Codends; Hexagonal meshes; Trawl selectivity; Simulation; Twine tensions; Catch force.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00215/32597/31061.pdf

An evaluation of multi-annual management strategies for ICES roundfish stocks
Provedor de dados: 5
Autores: Kell, L; Pilling, G; Kirkwood, G; Pastoors, M; Mesnil, Benoit; Korsbrekke, K; Abaunza, P; Aps, R; Biseau, Alain; Kunzlik, P; Needle, C; Roel, B; Ulrich, Clara.
Current scientific management objectives for ICES roundfish stocks are to ensure conservation of the biological resource and do not explicitly consider economic or social objectives. For example, there are currently no objectives to maximize the sustainable yield or to reduce variability in total allowable catches (TACs). This is despite the fact that the current system can result in wide annual fluctuations in TAC, limiting the ability of the fishing industry to plan for the future. Therefore, this study evaluated management strategies that stabilized catches by setting bounds on the interannual variability in TACs. An integrated modelling framework was used, which simulated both the real and observed systems and the interactions between system...
Tipo: Text
Palavras-chave: Whiting; TAC; Simulation; Saithe; Population modelling; North Sea; Management; Limiting variations; Harvest strategies; Hake; Haddock; Evaluation; Cod; Bounds.
Ano: 2006
URL: https://archimer.ifremer.fr/doc/2006/publication-3694.pdf

Comparison of synthetic turbulence approaches for blade element momentum theory prediction of tidal turbine performance and loads
Provedor de dados: 5
Autores: Togneri, Michael; Pinon, Grégory; Carlier, Clement; Choma Bex, Camille; Masters, Ian.
Turbulence is a crucial flow phenomenon for tidal energy converters (TECs), as it influences both the peak loads they experience and their fatigue life. To best mitigate its effects we must understand both turbulence itself and how it induces loads on TECs. To that end, this paper presents the results of blade element momentum theory (BEMT) simulations of flume-scale TEC models subjected to synthetic turbulent flows. Synthetic turbulence methods produce three-dimensional flowfields from limited data, without solving the equations governing fluid motion. These flowfields are non-physical, but match key statistical properties of real turbulence and are much quicker and computationally cheaper to produce. This study employs two synthetic turbulence generation...
Tipo: Text
Palavras-chave: BEMT; SEM; Sandia; Tidal turbines; Turbulence; Simulation.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00501/61248/64828.pdf

A bio-economic analysis of experimental selective devices in the Norway lobster (Nephrops norvegicus) fishery in the Bay of Biscay
Provedor de dados: 5
Autores: Raveau, Adriana; Macher, Claire; Mehault, Sonia; Merzereaud, Mathieu; Le Grand, Christelle; Guyader, Olivier; Bertignac, Michel; Fifas, Spyros; Guillen Garcia, Jordi.
Several fleets with various fishing strategies operate as a mixed fishery in the Bay of Biscay. Among the main fleets, bottom trawlers target Norway lobster (Nephrops norvegicus) and, together with gillnetters, they also catch hake (Merluccius merluccius). Trawling leads to average-size catches that are below the minimum landing size (MLS); such catches are discarded since they cannot be sold. These discards result in negative impacts on stock renewal, as most of them do not survive. This also results in an economic loss for both bottom trawlers and gillnetters since these discards represent a future loss of rent. This study, based on the 2009 and 2010 selectivity experiments at sea, assesses the short- and long-term bio-economic impacts of four...
Tipo: Text
Palavras-chave: Demersal trawl fishery; Bio-economic analysis; Selectivity; Simulation; Selective device; Nephrops norvegicus; Merluccius merluccius; Atlantic Ocean.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00110/22135/19774.pdf

Consequences of bias in age estimation on assessment of the northern stock of European hake (Merluccius merluccius) and on management advice
Provedor de dados: 5
Autores: Bertignac, Michel; De Pontual, Helene.
The results of a pilot tagging study on hake (Merluccius merluccius), conducted in the northern part of the Bay of Biscay in 2002, indicate that growth rates for this stock may be currently underestimated because of biased estimates of age. The impact that such a bias may have on the stock dynamics and the trends of the key population parameters, recruitment, spawning-stock biomass (SSB), and mortality are investigated. Assuming new growth parameters, a new age-length key is derived and used to produce and catch-at-age data and abundance indices, which are then used to assess the stock. Bias in estimating age affects the absolute levels of fishing mortality and stock biomass estimates, and also impacts the trend in SSB. However, trends in fishing mortality...
Tipo: Text
Palavras-chave: Tagging; Stock assessment; Simulation; Management; Growth; European hake; Age estimation.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2824.pdf

Bioeconomic modelling of English Channel fisheries and their technical interactions : presentation of the simulation model BECHAMEL (BioEconomic CHAnnel ModEL)
Provedor de dados: 5
Autores: Ulrich, Clara; Le Gallic, Bertrand; Dunn, Matthew R.
This paper presents the structure and examples of results from a bioeconomic model that stimulates the fisheries of the English Channel. The main purpose of the model is to study the consequences of various management alternatives on the economic situation of UK, French and Belgian fleets fishing in the area, and on exploited resources. Considering the large number of technical interactions, the whole Channel may be regarded as one large multi-country, multi-gear and multi-species fishery. The model describes this feature through the link between three entities : fleets, "métiers", and species caught. The empirical basis of the model is composed of UK, French and Belgian data concerning stocks, fleets and landings, and two economic sample surveys of UK and...
Tipo: Text
Palavras-chave: Bioeconomic modelling; English Channel fisheries; Multi species; Multifleet; Simulation.
Ano: 1999
URL: https://archimer.ifremer.fr/doc/00502/61353/64971.pdf

Towed Gear Optimisation, application to trawls
Provedor de dados: 5
Autores: Roullot, Jean; Vincent, Benoit.
IFREMER has been developing and commercialising scientific software to help the conception and optimisation of any kind of trawl. This software named DynamiT makes available a "virtual flume tank" where tests can be achieved without any constraint due to scale effects or other limitation when physically testing out. DynamiT has been used numbers of times to simulate and optimise trawls by different net makers and by IFREMER. The software is based on the resolution of the mechanics (structure and hydrodynamic) equations of a model describing the actual trawl and its rigging. The "user friendly" interface allows the user to iterate "modification and observations" cycles to reach an optimised state of the fishing gear. The process can be used to reduce the...
Tipo: Text
Palavras-chave: Hydrodynamic; Fuel consumption; Simulation; Model; DynamiT; Software; Fishing; Hydrodynamique; Consommation de carburant; Simulation; Modèle; DynamiT; Logiciel; Pêche.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-4613.pdf

Approche de la circulation residuelle en Baie de Seine
Provedor de dados: 5
Autores: Lehir, P; Salomon, J; Leprovost, C; Chabertd'Hieres, G; Mauvais, J.
By taking into account salinity measurements and consequently mean residence time, current measurements, tidal computation with a 2-D model and wind induced currents provided by a 3-D model, a global diagram of residual flow in Seine Bay is given. Main patterns are exhibited: density currents in the eastern part of the bay, off the Seine Estuary, wind induced circulation, especially along the coast and over the Channels, and tidal residual patterns induced by topography.
Tipo: Text
Palavras-chave: Simulation; Modelling; Wind driven circulation; Bottom topography; Density gradients; Water masses; River discharge; Haline circulation; Salinity gradients; Tidal currents; Residual flow.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/acte-1263.pdf

Symbolic Analysis of Plankton Swimming Trajectories: Case Study of Strobilidium sp. (Protista) Helical Walking under Various Food Conditions
Provedor de dados: 5
Autores: Vandromme, Pieter; Schmitt, François G.; Souissi, Sami; Buskey, Edward J.; Strickler, J. Rudi; Wu, Cheng-han; Hwang, Jiang-shiou.
The swimming behavior of the ciliate Strobilidium sp. was recorded using cinematographic techniques. A density of 20 ciliates/ml was used under 4 experimental food conditions: 121, 625, 3025, and 15,125 cells/ml of the dinoflagellate Gymnodinium sp. In total, 100 trajectories per experiment were recorded and analyzed. We classified this ciliate’s swimming trajectories into categories we called “helix”, “non-helix”, and “break”. These swimming states were identified using automated recognition of helices, based on values of swimming trajectory angles. We performed a symbolic analysis of the succession of swimming states which enabled discrimination between food concentration experiments, and provided a more-complete characterization of the swimming...
Tipo: Text
Palavras-chave: Protista; Plankton behavior; Swimming states; Symbolic dynamics; Simulation.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00070/18171/15730.pdf

Combining sensitivity and uncertainty analysis to evaluate the impact of management measures with ISIS-Fish: marine protected areas for the Bay of Biscay anchovy (Engraulis encrasicolus) fishery
Provedor de dados: 5
Autores: Lehuta, Sigrid; Mahevas, Stephanie; Petitgas, Pierre; Pelletier, Dominique.
Spatio-seasonal explicit simulation models can predict the impact of spatial management measures on marine fish populations and fishing activities. As fisheries are complex systems, fisheries simulation models are often complex, with many uncertain parameters. Here, the methodology is provided to deliver fishery diagnostics within an uncertainty context using a complex simulation tool. A sensitivity analysis of the model is performed on model outputs using partial least-squares to identify the most sensitive parameters. The impact of several management measures is then simulated using a statistical simulation design taking into account the uncertainty of the selected sensitive parameters. This approach was applied to the Bay of Biscay anchovy stock using...
Tipo: Text
Palavras-chave: Bay of Biscay anchovy; Marine protected area; Sensitivity analysis; Simulation; Uncertainty analysis.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00011/12234/9281.pdf

Approche experimentale du comportement d'une plaque composite sous effet d'un choc perforant
Provedor de dados: 5
Autores: Paris, P; Genin, D; Hamelin, P.
Our purpose in this paper is to study the behaviour of composite materials reinforced by glass satin weave 8 fabric under the impact of a projectile. The first part of this paper deals with experimental tests carried out using a servo-hydraulic machine. The hydraulic ram can be programmed to impact the specimen at any desired velocity between a few tenths of a millimetre per minute and 20 m/s. In the second part, these experimental results are compared with the numerical results of bidimensional finite difference code AUTODYN. This program allows the numerical simulation of the penetration of composite plates by projectiles.
Tipo: Text
Palavras-chave: Ship technology; Collisions; Materials testing; Simulation; Mathematical models; Numerical analysis; Composite materials; Essai de choc; Réponse dynamique; Simulation numérique; Plaque composite; Impact.
Ano: 1992
URL: http://archimer.ifremer.fr/doc/1992/acte-1045.pdf

Ocean-Atmosphere Coupling in the Monsoon Intraseasonal Oscillation: A Simple Model Study
Provedor de dados: 5
Autores: Bellon, Gilles; Sobel, Adam H.; Vialard, Jerome.
A simple coupled model is used in a zonally symmetric aquaplanet configuration to investigate the effect of ocean-atmosphere coupling on the Asian monsoon intraseasonal oscillation. The model consists of a linear atmospheric model of intermediate complexity based on quasi-equilibrium theory coupled to a simple, linear model of the upper ocean. This model has one unstable eigenmode with a period in the 30-60-day range and a structure similar to the observed northward-propagating intraseasonal oscillation in the Bay of Bengal/west Pacific sector. The ocean-atmosphere coupling is shown to have little impact on either the growth rate or latitudinal structure of the atmospheric oscillation, but it reduces the oscillation's period by a quarter. At latitudes...
Tipo: Text
Palavras-chave: Madden julian oscillation; Tropical circulation model; Sea surface temperature; Asian summer monsoon; Convective perturbations; Walker circulation; Radiation budget; Indian ocean; Variability; Simulation.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/00185/29637/27987.pdf

Modeling energy flow in a large Neotropical reservoir: a tool do evaluate fishing and stability
Provedor de dados: 83
Autores: Angelini,Ronaldo; Agostinho,Angelo Antonio; Gomes,Luiz Carlos.
Recently, there is an increasing perception that the ecosystem approach gives important insights to support fisheries stock assessment and management. This paper aims to quantify energy flows in the Itaipu Reservoir (Brazil) and to simulate increase of the fishing effort of some species, using Ecopath with Ecosim software, which could allow inferences on stability. Therefore, two steady-state Itaipu models were built (1983-87 and 1988-92). Results showed that: a) there are no differences between models, and results on aging trends do not vary over time indicating that fishery does not alter the ecosystem as a whole; b) results of fisheries simulations are approximate to mono-specific stock assessment for the same species and periods; c) many authors...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ecopath; Food web; Fisheries; Ecosystem; Simulation.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252006000200011

The kinetic analysis and simulation of hardening in bread made by the yudane dough method
Provedor de dados: 19
Autores: Tsuboi, Kazumasa; Ohara, Ami; Matsushita, Koki; Yamada, Daiju; Santiago, Dennis Marvin; Kawakami, Sakura; Koaze, Hiroshi; Yamauchi, Hiroaki.
Pullman type white breads with or without Yudane dough at 10 and 20% (w/w, flour base) were made by the no first fermentation method. Yudane dough was prepared by mixing boiling water and flour at a 1:1 ratio. The breads were stored at various temperature conditions and then subjected to analyses of bread hardening (temporal changes in hardness), hardening rate constant of bread (HRC), and simulation of hardening behavior using a hardening model. The results were as follows: The hardening of all breads slowed with the increase in storage temperature. The hardening of breads made with Yudane dough (Yudane breads) was slower than that without Yudane dough (Control) at any storage temperature. The HRC of all breads sharply decreased with the increase in...
Palavras-chave: Bread; Temperature; Hardening; Kinetic model; Simulation.
Ano: 2017
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4484

The effect of the Mbita Causeway on water currents in the region of Rusinga Channel, Winam Gulf, Lake Victoria: a 3D modelling study with ELCOM
Provedor de dados: 20
Autores: Romero, J.R.; Khisa, P.
The Mbita Causeway in Kenya was constructed in the early 1980’s to link Rusinga Island to the mainland to facilitate the transport of people, goods, and services to the island. One of the effects of the Causeway was to permanently block a secondary connection between Rusinga Channel and the offshore waters of Lake Victoria. This secondary channel may have served as a substantial pathway of exchange between Winam Gulf and Lake Victoria prior to the Causeway. There has been considerable scientific and political debate as to whether decreased flushing within the two bays on either side of the Causeway has occurred and led to poorer lake water quality since the construction of the barrier. In Apr.-May 2005 an intensive field investigation was undertaken to...
Tipo: Proceedings Paper
Palavras-chave: Hydrodynamics; Water quality; Channel flow; Development projects; Simulation; Modelling; Flushing; Environmental effects; Water currents; Inland water environment; Hydrodynamics; Http://aims.fao.org/aos/agrovoc/c_3723.
Ano: 2006
URL: http://hdl.handle.net/1834/1473

Numerical Simulation of the Influence of Mean Sea Level Rise on Typhoon Storm Surge in the East China Sea.
Provedor de dados: 20
Autores: Gao, Zhigang; Han, Shuzong; Liu, Kexiu; Zhrng, Yunxia; Yu, Huaming.
In this paper, ECOMSED (Estuarine Coastal Ocean Model with sediment transport) model is employed to simulate storm surge process caused by typhoon passing across East China Sea in nearly years. Capability of ECOMSED to simulate storm surge is validated by comparing model result with observed data. Sensitivity experiments are designed to study the influence of sea level rise on typhoon storm surge. Numerical experiment shows that influence of mean sea level rise on typhoon storm surge is non-uniform spatially and changes as typhoon process differs. Maybe fixed boundary method would weaken the influence of mean sea level rise on storm surge, and free boundary method is suggested for the succeeding study.
Tipo: Journal Contribution
Palavras-chave: Simulation; Sea level.
Ano: 2008
URL: http://hdl.handle.net/1834/5878

Estimacion de corrientes marinas en el Golfo de Batabano
Provedor de dados: 20
Autores: Arriaza Oliveros, L.; Simanca Cardenas, Y.; Rodas Fernández, L.; Milian, D.
The simulation operational tool known as SIMulación de COrrientes (SIMCO) is a part of a methodology to forecast marine currents into cuban shelf. This tool is based on a lineal model. Gulf of Batabanó is an almost closed shallow water body whit flat bottom, that includes a surface of 20 850 km2 and its average depth is about 6 m. This work offers the results of such a comparison between the results of the application of SIMCO to Gulf of Batabanó and current measurements. SIMCO is a good representation of the marine currents inside of the gulf, the overestimation mean error is equal to 3.8 cm/s for the south boundary of gulf when SIMCO run whit a kind of horizontal resolution of 2 nm and the overestimation errors decreases when the horizontal resolution...
Tipo: Conference Material
Palavras-chave: Ocean currents; Models; Simulation; Ocean currents; Models; Simulation; Http://aims.fao.org/aos/agrovoc/c_12883; Http://aims.fao.org/aos/agrovoc/c_4881; Http://aims.fao.org/aos/agrovoc/c_5209.
Ano: 2006
URL: http://hdl.handle.net/1834/2228

Simulation numérique du transport des sables sous l'effet des vents dans le Golfe de Tunis
Provedor de dados: 20
Autores: Koutitonsky, V.; Mouldi, Brahim; Bejaoui, B.; Sammari, Ch.
La dynamique sédimentaire le long de littoral est étroitement liée à la direction et à l’intensité des courants littoraux engendrés par les vents, les vagues et la marée. L’objectif de cette étude est de simuler numériquement la circulation et le transport des sédiments non cohésifs (sables) le long du littoral du golfe de Tunis sous l’effet unique des vents. Plusieurs directions des vents ont été imposées au modèle hydrodynamique MIKE21-HD tout en gardant  une vitesse constante de 7 m.s-1. Les courants stationnaires générés par ces vents ont ensuite servi à forcer le modèle de transport de sédiments non cohésifs MIKE21-ST. En supposant que la quantité de sable disponible est illimitée, les simulations montrent que les taux du transport de sédiment du côté...
Tipo: Journal Contribution
Palavras-chave: Nearshore currents; Sand; Sediment transport; Simulation; Water circulation; Winds; Sand; Simulation; Water circulation; Winds; Http://aims.fao.org/aos/agrovoc/c_6779; Http://aims.fao.org/aos/agrovoc/c_5209; Http://aims.fao.org/aos/agrovoc/c_8314; Http://aims.fao.org/aos/agrovoc/c_8401.
Ano: 2007
URL: http://hdl.handle.net/1834/4256

Evaluación de los índices de abundancia para corvina rubia (Micropogonias furnieri) y pez palo (Percophis brasiliensis) obtenidos mediante modelos lineales generales: simulaciones de Monte Carlo y análisis de las interacciones con el factor año
Provedor de dados: 20
Autores: Rico, M.R.; Hernández, D.R.; Carozza, C.R.
Assessment of abundance indexes for whitemouth croaker (Micropogonias furnieri) and brazilian flathead (Percophis brasiliensis) obtained with general linear models: Monte Carlo simulation and analysis of the interactions with the “year” factor. The effect of interactions with the year factor on the annual index of relative abundance obtained with general linear models applied to the cath per unit of effort data of whitemouth croaker and brazilian flathead commercial fleet was evaluated applying the Monte Carlo simulation. Levels on the relative percentage of variance explained by the interactions with the year factor (%RVEAÑO) were determined, above which loss of proportionality between the relative abundance series given by the index and the real series...
Tipo: Journal Contribution
Palavras-chave: Stock assessment; Abundance; Catch/effort; Simulation; Commercial species; Coastal fisheries.
Ano: 2013
URL: http://hdl.handle.net/1834/5503

Determinación de tamaños de muestra en la pesquería de alfonsino, merluza de cola y besugo, zona centro sur.
Provedor de dados: 20
Autores: Young, Z.
1. Introducción En el marco del Programa de Seguimiento se continúo con la revisión y determinación de tamaños de muestra para estimar una serie de indicadores biológicos en las pesquerías demersales de la zona centro sur del país. En este estudio se entrega el soporte de determinación de tamaño de muestra para estimar la distribución de talla de la captura, la talla media, la proporción sexual y proporción de ejemplares bajo talla de referencia correspondiente a alfonsino (Beryx splendens), merluza de cola (Macruronus magellanicus) y besugo (Espigonus crassicaudus). 2. Métodos 2.1 Datos El conjunto de datos seleccionados y utilizados en la simulación debe ser lo suficientemente grande como para suponer que en él se recoge el rango de variabilidad real...
Tipo: Working Paper
Palavras-chave: Size; Sampling; Simulation; Sampling; Simulation; Size; Http://aims.fao.org/aos/agrovoc/c_6774; Http://aims.fao.org/aos/agrovoc/c_5209; Http://aims.fao.org/aos/agrovoc/c_7093.
Ano: 2006
URL: http://hdl.handle.net/1834/1509

Ecología trófica de la merluza común (Merluccius hubbsi) del Mar Argentino. Parte 3. Consumo anual de alimento a nivel poblacional y su relación con la explotación de las pesquerías multiespecíficas.
Provedor de dados: 20
Autores: Prenski, L.B.; Angelescu, V.
The English contents gives a general view on the topics treated in this contribution developed mainly on the basis of a quantitative and ecological analysis of trophic relationships in the Argentinian Continental Shelf, in which common hake and its food species are involved (anchovy, mictophids, small fishes, squids and macrozooplankton crustaceans). The most original part consist in the application of bioenergetic and simulation models for estimating the annual food consumption by individuals and by stocks of common hake during 1970-1987, considering at the same time, the effects of commercial catches on the stockbiomasses in predator-prey relationships. From this point of view three trophic-fishery relationships are evident, namely: "Common...
Tipo: Journal Contribution
Palavras-chave: Trophic relationships; Food consumption; Mathematical models; Simulation; Biomass; Food consumption; Simulation; Biomass; Mathematical models; Http://aims.fao.org/aos/agrovoc/c_3016; Http://aims.fao.org/aos/agrovoc/c_5209; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_24199.
Ano: 1993
URL: http://hdl.handle.net/1834/2557

Sensitivity analysis of the AquaCrop parameters for rainfed corn in the South of Brazil
Provedor de dados: 86
Autores: Martini,Luiz Carlos Pittol.
Abstract: The objective of this work was to perform a sensitivity analysis of the main input parameters required for the AquaCrop water balance model, using biomass and grain yield data of a rainfed-simulated corn crop, obtained along the climate data series of 1987-2016 in the South of Brazil. The levels of soil-water stress and the depths of maximum effective rooting were the input parameters that most affected the biomass and grain yields simulated by the model, followed by the crop coefficient, water-use efficiency, soil water storage capacity, and contribution of groundwater to water availability in the root zone. The parameters crop cycle duration, plant density, pattern of soil-water extraction, and field surface practices showed little or no impact...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Crop model; Drought; Simulation; Soil-water balance; Soil-water stress.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018000800934

Sample size for full-sib family evaluation in sugarcane
Provedor de dados: 86
Autores: Leite,Mauro Sergio de Oliveira; Peternelli,Luiz Alexandre; Barbosa,Márcio Henrique Pereira; Cecon,Paulo Roberto; Cruz,Cosme Damião.
The objective of this study was to determine the minimum number of plants per plot that must be sampled in experiments with sugarcane (Saccharum officinarum) full-sib families in order to provide an effective estimation of genetic and phenotypic parameters of yield-related traits. The data were collected in a randomized complete block design with 18 sugarcane full-sib families and 6 replicates, with 20 plants per plot. The sample size was determined using resampling techniques with replacement, followed by an estimation of genetic and phenotypic parameters. Sample-size estimates varied according to the evaluated parameter and trait. The resampling method permits an efficient comparison of the sample-size effects on the estimation of genetic and phenotypic...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Saccharum officinarum; Cane breeding; Simulation; Statistical methods; Variance components.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009001200002

Impact of increasing mean air temperature on the development of rice and red rice
Provedor de dados: 86
Autores: Lago,Isabel; Streck,Nereu Augusto; Alberto,Cleber Maus; Oliveira,Felipe Brendler; Paula,Gizelli Moiano de.
The objective of this study was to assess the development response of cultivated rice and red rice to different increases in minimum and maximum daily air temperatures, in Santa Maria, Rio Grande do Sul State, Brazil. One hundred years climate scenarios of temperatures 0, +1, +2, +3, +4, and +5ºC, with symmetric and asymmetric increases in minimum and maximum daily air temperatures were created, using the LARS-WG Weather Generator, and a 1969-2003 database. Nine cultivated rice genotypes (IRGA 421, IRGA 416, IRGA 417, IRGA 420, BRS 7 TAIM, BR-IRGA 409, EPAGRI 109, EEA 406 and a hybrid), and two red rice biotypes (awned black hull-ABHRR, and awned yellow hull-AYHRR) were used. The dates of panicle differentiation (R1), anthesis (R4), and all grains with...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Oryza sativa; Global warming; Phenology; Simulation; Weeds.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008001100001

VALUE OF SOCIAL CAPITAL TO MID-SIZED NORTHERN PLAINS FARMS
Provedor de dados: 31
Autores: Gustafson,   Cole R.
As farms increase in size, operators face the decision of remaining loyal to local merchants or obtaining volume discounts from distant input suppliers.  When farmers bypass local merchants and buy inputs in volume, they often realize price discounts but forego many services including credit forebearance.  When farmers buy locally, they pay higher prices, which decreases profits and increases financial risk, but generates social capital which can be drawn upon during periods of economic adversity.  A theoretical model of farm financial risk evaluates borrower behavior in light of cash flow constraints, volume discounts, and social capital.  Results delineate financial risks involved and value of social capital.
Tipo: Conference Paper or Presentation
Palavras-chave: Capital; Financial risk; Simulation; Social; Stochastic; Agricultural Finance.
Ano: 2005
URL: http://purl.umn.edu/19169

Decision Support System for Evaluating Rural Water Supply Infrastructure Scenarios
Provedor de dados: 31
Autores: Stoecker,   Arthur L.; Sanders,   Dee Ann; Whitacre,   Brian E.
This paper seeks to develop a methodology that will be useful for rural water districts in assessing the future of their water systems infrastructure.  In particular, the use of free water simulation software and publicly available data on population, roads, and terrain present rural water systems with the opportunity to analyze their existing distribution system and forecast where problems are likely to occur.  This methodology will allow various alternatives (such as consolidation with a neighboring system, or pipe upgrades) to be evaluated and the costs of implementing these alternatives to be explored.  Finally, different avenues for funding the associated costs can be summarized and presented to the community, including the steps needed to apply for...
Tipo: Conference Paper or Presentation
Palavras-chave: Rural Water; Infrastructure; Simulation; EPANET; Community/Rural/Urban Development; R53; R58.
Ano: 2009
URL: http://purl.umn.edu/56526

PROCUREMENT RISKS AND STRATEGIES TO IMPROVE QUALITY CONSISTENCY IN WHEAT SHIPMENTS
Provedor de dados: 31
Autores: Wilson,   William W.; Dahl,   Bruce L.
Consistency of functional characteristics in wheat is a concern confronting buyers and sellers.  This research analyzes the cost and risk of different procurement strategies for importers.  A stochastic simulation model is used to determine the  probability of a functional characteristic being satisfied subject to quality targets and costs for alternative purchase strategies (purchase by protein only, variety, location, variety by location, or functional tests).  Joint probabilities of meeting specifications and costs were determined for the alternative purchase strategies.  Stochastic dominance was used to determine which purchase strategies dominate others, and stochastic efficiency was utilized to determine the degree of preference.  Results indicate...
Tipo: Working or Discussion Paper
Palavras-chave: Buying Strategies; Location; Variety; Functional Characteristic Tests; Costs; Risks; Simulation; Stochastic Dominance; Crop Production/Industries; Risk and Uncertainty.
Ano: 2007
URL: http://purl.umn.edu/23498

Production Inefficiency in Fed Cattle Marketing and the Value of Sorting Pens into Alternative Marketing Groups Using Ultrasound Technology
Provedor de dados: 31
Autores: Koontz,   Stephen R.; Hoag,   Dana L.; Brethour,   John R.; Walker,   Jodine L.
The cattle industry batch markets animals in pens. Because of this, animals within any one pen can be both underfed and overfed. Thus, there is a production inefficiency associated with batch marketing. We simulate the value of sorting animals through weight and ultrasound measurements from original pens into smaller alternative marketing groups. Sorting exploits the production inefficiency and enables cattle feeding enterprises to avoid meat quality discounts, capture premiums, more efficiently use feed resources, and increase returns. The value of sorting is between $15 and $25 per head, with declining marginal returns as the number of sort groups increases.
Tipo: Journal Article
Palavras-chave: Cattle feeding; Production efficiency; Simulation; Sorting; Value-based marketing; Ultrasound; Agribusiness; Livestock Production/Industries; Marketing; Research and Development/Tech Change/Emerging Technologies; C15; D21; D23; Q12.
Ano: 2008
URL: http://purl.umn.edu/47266

THE AGRICULTURAL POLICY SIMULATOR (AGRIPOLIS) – AN AGENT-BASED MODEL TO STUDY STRUCTURAL CHANGE IN AGRICULTURE (VERSION 1.0)
Provedor de dados: 31
Autores: Happe,   Kathrin; Balmann,   Alfons; Kellermann,   Konrad.
A central criticism common to agricultural economic modelling approaches for policy analy-sis is that they do not adequately take account of a number of characteristic factors of the agri-cultural sector. This concerns aspects like the immobility of land, heterogeneity of farms, in-teractions between farms, space, dynamic adjustment processes as well as dynamics of struc-tural change. In brief, modelling the complexity of the system has not been at the centre of interest. In terms of modelling complex economic systems, an agent-based modelling ap-proach is a suitable approach to quantitatively model and understand such systems in a more natural way. In the same way, this applies to the modelling of agricultural structures. In par-ticular, agent-based...
Tipo: Working or Discussion Paper
Palavras-chave: Agent-based systems; Multi-agent systems; Policy analysis; Structural change; Simulation; Agentenbasierte Systeme; Politikanalyse; Dynamische An-passungsprozesse und Strukturwandel. Kurz; Multi-Agentensysteme; Struktur-wandel; Agricultural and Food Policy; Q12; Q15.
Ano: 2004
URL: http://purl.umn.edu/14886

VALUING AGRICULTURAL MORTGAGE-BACKED SECURITIES
Provedor de dados: 31
Autores: Stokes,   Jeffrey R.; Brinch,   Brian M.
A model to value Federal Agricultural Mortgage Corporation (Farmer Mac) agricultural mortgage-backed securities (AMBS) is developed and numerically solved.  The results suggest prepayment penalties currently being used by Farmer Mac reduce yields on AMBS considerably.  Even with prepayment penalties, it can be advantageous for profit maximizing mortgagors to optimally prepay or even default on agricultural mortgages.  The model is used to quantify prepayment and default risk by valuing the embedded options in the mortgages.  Monte Carlo simulation is also used to determine the probability to optimal prepayment given the term structure assumption used to develop the model.
Tipo: Journal Article
Palavras-chave: Agricultural mortgage-backed securities; Default; Dynamic programming; Simulation; Prepayment; Agricultural Finance; G13; G21.
Ano: 2001
URL: http://purl.umn.edu/15459

A Whole Farm Analysis of the Influence of Auto-Steer Navigation on Net Returns, Risk, and Production Practices
Provedor de dados: 31
Autores: Shockley,   Jordan M.; Dillon,   Carl R.; Stombaugh,   Timothy S.
A whole farm economic analysis was conducted to provide a detailed assessment into the economic, risk, and production implications due to the adoption of auto-steer navigation. It was determined that auto-steer navigation was profitable for a grain farmer in Kentucky with net returns increasing up to 0.90% ($3.35/acre). Additionally, the technology could be used in reducing production risk. Adoption of the technology also alters production practices for optimal use.
Tipo: Journal Article
Palavras-chave: Economics; Farm management; Mean-variance; Precision agriculture; Simulation; Farm Management; Risk and Uncertainty; C61; C63; D81; Q12; Q16.
Ano: 2011
URL: http://purl.umn.edu/100640

THE USE OF BIOPHYSICAL AND EXPECTED PAYOFF PROBABILITY SIMULATION MODELING IN THE ECONOMIC ASSESSMENT OF BRUSH MANAGEMENT ALTERNATIVES
Provedor de dados: 31
Autores: Schumann,   Keith D.; Conner,   J. Richard; Richardson,   James W.; Stuth,   Jerry W.; Hamilton,   Wayne T.; Drawe,   D. Lynn.
Woody plant encroachment restricts forage production and capacity to produce grazing livestock.  Biophysical plant growth simulation and economic simulation were used to evaluate a prescribed burning range management technique.  Modeling systems incorporated management practices and costs, historical climate data, vegetation and soil inventories, livestock production data, and historical regional livestock prices.  The process compared baseline non-treatment return estimates to expected change in livestock returns resulting from prescribed burning.  Stochastic analyses of production and price variability produced estimates of greater net returns resulting from use of prescribed burning relative to the baseline.
Tipo: Journal Article
Palavras-chave: Biophysical simulation; Prescribed burning; Range management; Simulation; Land Economics/Use.
Ano: 2001
URL: http://purl.umn.edu/15452

SOME ECONOMIC ASPECTS OF THE HUNGARIAN BIOFUEL PROGRAMS
Provedor de dados: 31
Autores: Lakner,   Zoltan; Szabo-Burcsi,   Dora; Mago,   Laszlo.
The use of renewable materials in energy production is gaining in importance all over the world. The production of bioethanol and biodiesel is an important element of the agricultural strategy of numerous countries, even though the economic and environmental impact of these projects is subject to significant debates. Our paper analyses the welfare effects of the Hungarian bioethanol programme, as well as the economic feasibility of the projects. It can be demonstrated that the Hungarian bioethanol programme will cause a rather marginal increase in agricultural prices.  The cost of bioethanol production is estimated between 470 and 630 €/m3, influenced by numerous factors. This estimate is in line with the average European values. The possibilities for...
Tipo: Journal Article
Palavras-chave: Comparative analysis; Simulation; Return on investment; Welfare economics; Beruházás-gazdaságosság; Összehasonlító vizsgálat; Jóléti elemzés; Szimuláció.; Agricultural and Food Policy; Environmental Economics and Policy.
Ano: 2010
URL: http://purl.umn.edu/99205

INCOME DISTRIBUTIONAL IMPACTS OF TRADE POLICIES IN A MULTI-MARKET FRAMEWORK: A CASE IN PAKISTAN
Provedor de dados: 31
Autores: Hudson,   Darren; Ethridge,   Don E.
The impacts of using export taxes as a price control in a multi-market framework are explored using the cotton and yarn sectors in Pakistan as examples. Results show that the export tax on cotton increased domestic consumption and decreased exports of cotton in Pakistan, transferring income from cotton producers to yarn spinners and the government. There was a social loss to Pakistan in the cotton sector. The export tax on cotton increased domestic yarn production, consumption, exports, and incomes of yarn spinners, but resulted in a large transfer (social loss) out of the yarn sector.
Tipo: Journal Article
Palavras-chave: Cotton; Export tax; Simultaneous equations; Simulation; Policy; International Relations/Trade.
Ano: 2000
URL: http://purl.umn.edu/15398

System Approach for Evaluating Locally Grown Produce Issues
Provedor de dados: 31
Autores: Berruto,   Remigio; Busato,   Patrizia.
The potential advantages of locally grown produce are mainly related to the coexistence of production and consumption in the same area. These advantages are: reduced transportation, freshness, better taste, easy traceability, transparency, food safety, environmental sustainability and community development. Despite these positive aspects, the money spent for locally grown produce represents only a small percentage of the total money spent for fresh produce purchases. On the other hand, interest is growing for furnishing produce to local produce schools, hospitals and public institutions. The supply chains of locally grown produce are classified into direct marketing distributions (farmers’ markets, CSAs, roadside stands, on-farm stores) and indirect...
Tipo: Book
Palavras-chave: System approach; Locally grown; Supply–chain; Fruits and vegetables; Logistics; Simulation; Agribusiness; Agricultural and Food Policy; Farm Management; Food Consumption/Nutrition/Food Safety.
Ano: 2009
URL: http://purl.umn.edu/58713

Agricultural policy (AP2011) Reform and the WTO: Potential Impacts on Swiss Agriculture
Provedor de dados: 31
Autores: Ferjani,   Ali.
This article analyses the impact of the planned Swiss package of agricultural policy measures AP2011 and the tariff reductions scheduled as part of the WTO Doha Round, with special emphasis on effects in the dairy and meat sector. The simulations are carried out using an extended partial equilibrium model. This article discusses the anticipated impact of changing structural conditions on production, processing, consumption, prices and exports in the milk market. If account is taken of the Bilateral Agreements between Switzerland and the EU providing for liberalisation of the common cheese market, raw milk production increases by 10.5 %, whereas the milk price shows a significant drop to around 60 centimes per kilogram of milk. The abolition of subsidies...
Tipo: Conference Paper or Presentation
Palavras-chave: Partial equilibrium model; Simulation; AP2011; WTO; Dairy industry; Agricultural and Food Policy; International Relations/Trade; Livestock Production/Industries.
Ano: 2008
URL: http://purl.umn.edu/6638

Analyzing Crop Revenue Safety Net Program Alternatives and Impacts on Producers and Program Costs
Provedor de dados: 31
Autores: Jansen,   Jim A.; Lubben,   Bradley D.; Stockton,   Matthew C.
This study evaluates the policy effects of alternative program designs for federal revenue-based farm income safety net programs.  Eight representative farms across Nebraska are used to stochastically simulate the financial impact of changing the current farm crop revenue-based safety net with a state revenue trigger against potential alternative programs involving guarantees at the district, county, or farm level.  Results indicate that decreasing the aggregation of the revenue guarantee increases expected farm-level payments and program costs for the revenue-based safety net.
Tipo: Presentation
Palavras-chave: Agricultural policy; Farm bill; Farm programs; Government payments; Representative farms; Risk management; Simulation; Agricultural and Food Policy; Farm Management; Risk and Uncertainty; Q12; Q18.
Ano: 2012
URL: http://purl.umn.edu/119784

ACCOUNTING FOR SPATIAL CHARACTERISTICS OF WATERSHEDS IN EVALUATING WATER POLLUTION ABATEMENT POLICIES
Provedor de dados: 31
Autores: Qiu,   Zeyuan; Prato,   Anthony A.
This study evaluates three agricultural nonpoint pollution abatement policies: regulating the spatial pattern of agricultural activities, ambient tax, and abatement tax/subsidy.  All three policies incorporate spatial characteristics of agricultural emission loading and movement for an agricultural watershed in the Midwest.  The effects of spatial variation in natural conditions and landscape features on agricultural emissions and crop yield are evaluated using a newly developed biophysical simulation model and experimental data.  While the policies are equally cost effective in reducing agricultural nonpoint source pollution, their implementation feasibility is quite different.
Tipo: Journal Article
Palavras-chave: Atrazine; Environmental policy; Nonpoint pollution; Simulation; Watershed management; Water quality; Environmental Economics and Policy.
Ano: 1999
URL: http://purl.umn.edu/15135

The Relative Performance of In-Sample and Out-of-Sample Hedging Effectiveness Indicators
Provedor de dados: 31
Autores: Dahlgran,   Roger A.
Hedging effectiveness is the proportion of price risk removed through hedging. Empirical hedging studies typically estimate a set of risk minimizing hedge ratios, estimate the hedging effectiveness statistic, apply the estimated hedge ratios to a second group of data, and examine the robustness of the hedging strategy by comparing the hedging effectiveness for this "out-of-sample" period to the "in-sample" period. This study focuses on the statistical properties of the in-sample and out-of-sample hedging effectiveness estimators. Through mathematical and simulation analysis we determine the following: (a) the R2 for the hedge ratio regression will generally overstate the amount of price risk reduction that can be achieved by hedging, (b) the properly...
Tipo: Conference Paper or Presentation
Palavras-chave: Out-of-sample; Post sample; Hedging; Effectiveness; Forecasts; Simulation; Agribusiness; Agricultural Finance; Demand and Price Analysis; Farm Management; Financial Economics; Marketing; Research Methods/ Statistical Methods; Risk and Uncertainty.
Ano: 2009
URL: http://purl.umn.edu/53042

Optimal Marketing Strategies for Southeastern Cattle Producers
Provedor de dados: 31
Autores: Pruitt,   J. Ross; Riley,   John Michael.
Tipo: Conference Paper or Presentation
Palavras-chave: Hedging; Cattle; Simulation; Expected Utility; Agribusiness; Farm Management; Livestock Production/Industries; Marketing; Q13.
Ano: 2009
URL: http://purl.umn.edu/98849

An Economic Assessment of the BSE Crisis in Canada: Impact of Border Closure and BSE Recovery Programs
Provedor de dados: 31
Autores: Weerahewa,   Jeevika; Meilke,   Karl D.; Le Roy,   Danny G.
This article assesses the economic consequences of three alternative government responses to the BSE crisis in Canada: 1) expansion in slaughter capacity; 2) partial destruction of the cattle herd; and 3) deficiency payments. Each of these policies is evaluated under four different border situations: 1) autarky; 2) free trade in young beef only; 3) free trade in young beef and cattle; and 4) complete free trade. The results of the policy analysis are quite sensitive to the border assumptions, making it impossible to select a “best” policy without perfect foresight with respect to the timing and the extent of the border opening.
Tipo: Journal Article
Palavras-chave: BSE; Cattle and beef; Partial equilibrium model; Simulation; Trade ban; International Relations/Trade; Livestock Production/Industries.
Ano: 2008
URL: http://purl.umn.edu/6176

CAP-reform and the provision of non-commodity outputs in Brandenburg
Provedor de dados: 31
Autores: Happe,   Kathrin; Damgaard,   Martin; Osuch,   Amanda; Sattler,   Claudia; Zander,   Peter; Uthes,   Sandra; Schuler,   Johannes; Piorr,   Annette.
This paper presents an attempt to model the response of selected farms to decoupled direct payments and the associated impact on the provision of a defined set of non-commodity outputs (NCO’s) using a combined modelling approach consisting of the AgriPoliS and MODAM models. AgriPoliS focuses on the socio-economic dimension of multifunctionality at the individual farm and regional levels and explicitly models heterogeneous farms (in size, location and efficiency) within a competitive and dynamic environment. The linear-programming model MODAM allows a detailed representation of production processes and their impact on the environmental dimension of multifunctionality at the farm level. We simulate the impact of a uniform area payment and a fully decoupled...
Tipo: Journal Article
Palavras-chave: Decoupling; Multifunctionality; Non-commodity outputs; Modelling; Simulation; Policy analysis; Ecological indicators; Agricultural and Food Policy; Land Economics/Use.
Ano: 2006
URL: http://purl.umn.edu/97193

Simulation of Alternative Marketing Strategies for U.S. Cotton
Provedor de dados: 31
Autores: Elrod,   Christopher P.; Robinson,   John R.C.; Richardson,   James W.
Three marketing strategies (selling a put option, cash sale at harvest, and cash sale in June) are simulated based on historical values and ranked based on certainty equivalents for a representative irrigated and dryland cotton farm Scenario analysis is also used to compare varying yield values.
Tipo: Conference Paper or Presentation
Palavras-chave: Simulation; Marketing; Cotton; Risk; Marketing; Research Methods/ Statistical Methods.
Ano: 2008
URL: http://purl.umn.edu/6885

IFECO – Modelling the Agro-Fuel Chain for Energy Cogeneration
Provedor de dados: 31
Autores: Rosa,   Franco.
Policy makers are searching for viable strategies to produce alternative energies; the agricultural sector can become an important supplier of renewable energy. The paper will develop the IFECO (integrated farm energy cogeneration) approach, a conceptual model of farm though as it were an "island economy"a a net energy exporter as the energy output exceeds the direct energy (cultivation, cropping, plant protection, transport, harvesting, storage) and indirect energy (fertilizer, pesticide, machinery, plantationforce, others) used in sunflower cultivation. IFECO is based on the cogeneration that is the production of different energies from a single agricultural commodity to achieve the three targets that make this project sustainable: i) economic...
Tipo: Conference Paper or Presentation
Palavras-chave: IFECO; Renewable energy; Biodiesel; Cogeneration; Sunflower; Simulation; Agribusiness; Resource /Energy Economics and Policy.
Ano: 2007
URL: http://purl.umn.edu/6578

Feasible Fumigant-Herbicide System Alternatives to Methyl Bromide for Bell Pepper Producers
Provedor de dados: 31
Autores: Byrd,   Mark M.; Escalante,   Cesar L.; Fonsah,   Esendugue Greg; Wetzstein,   Michael E.
With the current methyl bromide (MeBr) system for producing Georgia’s peppers being phased out, alternative fumigant and herbicide systems for producers are analyzed. Using stochastic dominance analyses, two alternatives exceeding MeBr’s yield and financial efficiency were identified. A programming model, incorporating simulation-optimization techniques, generated optimal production and financial plans. Results indicate potential economic viability under alternative systems vis-à-vis the traditional MeBr production system. The Telone II and Chloropicrin combination with Metham potassium may offer a viable substitute for MeBr.
Tipo: Journal Article
Palavras-chave: Fumigant; Herbicide; Methyl bromide; Multi-period programming; Optimization; Simulation; Stochastic dominance; Agribusiness; Crop Production/Industries.
Ano: 2007
URL: http://purl.umn.edu/62283

The Impacts of Farm Size and Economic Risk on No-Till Rice Whole-Farm Profitability
Provedor de dados: 31
Autores: Watkins,   K. Bradley; Hignight,   Jeffrey A.; Anders,   Merle M.
This study evaluated the impacts of farm size and stochastic return variability on no-till (NT) rice profitability at the whole-farm level. Mixed integer programming was used to determine optimal machinery complements, fuel consumption, and machinery labor requirements for conventional till (CT) and NT rice-soybean farms of 1200, 2400, and 3600 acres in size. Crop yields, market prices, and prices for key production inputs were simulated to construct stochastic whole-farm net returns for each farm size under CT and NT management, and both first and second degree stochastic dominance analysis were used to rank cumulative distribution functions of whole-farm returns according to specified risk preferences. The results indicate NT farms exhibit second degree...
Tipo: Conference Paper or Presentation
Palavras-chave: Mixed integer programming; No-till; Profitability; Rice; Risk; Simulation; Stochastic dominance; Whole-farm; Farm Management; Production Economics; Risk and Uncertainty.
Ano: 2011
URL: http://purl.umn.edu/98733

Enhancing Learning via the Internet: The Internet Agricultural Bank Simulation Game
Provedor de dados: 31
Autores: Briggeman,   Brian C.; Detre,   Joshua D.; Doye,   Damona G.; Lansford,   Notie H., Jr.
The Oklahoma Agricultural Bank Simulation Game (Ag Bank Sim) is a software based, experiential learning tool through which participants historically have learned key financial, economic, and banking lessons. The game offers a “real world” experience in which management decisions affect institutions interacting in a geographic market, enhancing understanding of the complex, competitive environment within which commercial banks operate. A new Internet version of the game has been developed, allowing participants to play Ag Bank Sim in a virtual environment. This poster highlights features of the game and reports results of pre and post tests of undergraduate students playing the game at Louisiana State University and Oklahoma State University in the spring...
Tipo: Conference Paper or Presentation
Palavras-chave: Banking; Simulation; Experiential learning; Agricultural Finance; Financial Economics; Teaching/Communication/Extension/Profession.
Ano: 2010
URL: http://purl.umn.edu/61409

ECONOMIC INCENTIVES FOR PST ADOPTION BY MIDWEST HOG PRODUCERS
Provedor de dados: 31
Autores: Richardson,   James W.; Anderson,   David P.; Peel,   Derrell S.; Phillips,   Mike.
A whole-farm simulation model is used to analyze the impacts of PST adoption on representative farms in Missouri and Indiana. Farmers who do not adopt experience lower average annual net cash farm incomes than adopters. Lower feed prices and/or an average PST/feed response decrease the incentive adopt. Payment of a 5 percent carcass merit premium (CMP) and/or higher grain prices greatly increase the economic incentive to adopt.
Tipo: Journal Article
Palavras-chave: Carcass merit premium; PST; Simulation; Livestock Production/Industries.
Ano: 1993
URL: http://purl.umn.edu/15032

Simulated Analysis of Drought's Impact on Different Cow-Calf Production Systems
Provedor de dados: 31
Autores: Stockton,   Matthew C.; Wilson,   Roger K.
Five representative firm level stochastic simulation models were constructed using historical production cost, cattle prices, weather information and scientifically collected production data from the Gundmendson Sandhills Laboratory operated by University of Nebraska. The five hundred iterative results indicate inclusion of crop residual grazing as a viable drought mitigation tool.
Tipo: Conference Paper or Presentation
Palavras-chave: Drought Mitigation; Firm Level; Residual Grazing; Simulation; Stochastic; Livestock Production/Industries.
Ano: 2007
URL: http://purl.umn.edu/34981

Financial and Risk Management Assistance: Decision Support for Agriculture
Provedor de dados: 31
Autores: Klose,   Steven L.; Outlaw,   Joe L.
The Financial and Risk Management (FARM) Assistance program created by Texas Cooperative Extension is a strategic analysis service offered to farmers and ranchers in Texas.  The program serves as an example of large-scale, focused programming by extension agencies, as well as the implementation of technical stochastic simulation methods for use on the farm.
Tipo: Journal Article
Palavras-chave: Decision information; Decision support system; Extension programming; Farm level analysis; Outreach; Simulation; Q16; Q12; C15; D83.
Ano: 2005
URL: http://purl.umn.edu/43516

Evaluation of Risk Management Methods for Satsuma Mandarin
Provedor de dados: 31
Autores: Lindsey,   Jeanne K.; Duffy,   Patricia A.; Nelson,   Robert G.; Ebel,   Robert C.; Dozier,   William A.
Simulation of production budgets were used to compare net discounted returns and the distribution of returns under alternative risk-mitigation scenarios.  Results indicate that the combination of freeze protection and crop insurance increases expected net discounted 20-year returns while decreasing the downside risk.  Break-even prices ranged from $.257 to $.289 per pound.  Crop insurance returns were constant across price.
Tipo: Conference Paper or Presentation
Palavras-chave: Satsuma oranges; Freeze protection; Crop insurance; Production budget; Simulation; Crop Production/Industries; Farm Management; Risk and Uncertainty; C63; D81; Q12.
Ano: 2009
URL: http://purl.umn.edu/46754

The Cattle Price Cycle: An Exploration in Simulation
Provedor de dados: 31
Autores: Stockton,   Matthew C.; Van Tassell,   Larry W.
The simulation of commodity prices has been undertaken using a myriad of techniques, with some omitting the cyclical component and others ignoring the presence of inter-temporal relationships expressed as autoregressive errors. This study examines the periodicity of cattle prices and the modeling of the cattle cycle for simulation purposes. The AIC criterion is used to determine lengths of various cycles to be included in a harmonic model, with a chained modeling approach providing the best representation of the cattle cycle.
Tipo: Conference Paper or Presentation
Palavras-chave: Cattle Price cycle; Harmonic model; Simulation.
Ano: 2007
URL: http://purl.umn.edu/37564

Do-it-yourself shuffling and the number of runs under randomness
Provedor de dados: 31
Autores: Smeeton,   Nigel; Cox,   Nicholas J.
A common class of problem in statistical science is estimating, as a benchmark, the probability of some event under randomness. For example, in a sequence of events in which several outcomes are possible and the length of the sequence and number of outcomes of each type known, the number of runs gives an indication of whether the outcomes are random, clustered, or alternating. This note explains and illustrates a simple method of random shuffling that is often useful. We show how the conditional probability distribution of the number of runs may be derived easily in Stata, thus yielding p-values for testing the null hypothesis that the type of outcome is random. We also compare our direct approach with that using the simulate command.
Tipo: Journal Article
Palavras-chave: Alternation; Categorical data; Clustering; Conditional distribution; Forvalues; P-value; Permutation; Run; Sequence; Simulate; Simulation; Research Methods/ Statistical Methods.
Ano: 2003
URL: http://purl.umn.edu/116095

Introducing Different Land Uses (Irrigated and Non-Irrigated) in Policy Analysis Modelling for Mediterranean Countries
Provedor de dados: 31
Autores: Casado,   Jose Maria; Gracia,   Azucena.
The arable crop sector in Spain is highly dependent of the Community subsidies and account for 33% of total transfers received by the Community.  Then, it is expected that the introduction of the Single Farm Payment (SFP) will drive important changes in the arable crop production in Spain.  The quantitative assessment of the SFP impacts on the arable crop sector in Spain is the overall objective of this paper.  To achieve this goal, an econometric, dynamic, multi-product and partial equilibrium commodity model has been built disaggregating between irrigated and non-irrigated land use for cereals called Spanish Econometric Simulation of Agricultural Policies (SESAP).  Results indicated that the introduction of the SFP has only induced considerable changes...
Tipo: Conference Paper or Presentation
Palavras-chave: CAP reform; Partial equilibrium model; Policy modelling; Irrigated agriculture; Simulation; Land Economics/Use; Q12; Q18.
Ano: 2006
URL: http://purl.umn.edu/25709

Grain Marketing Strategies Within and Across Lifetimes
Provedor de dados: 31
Autores: Peterson,   Hikaru Hanawa; Tomek,   William G.
To reconcile the discrepancy between the efficient market hypothesis and grain marketing recommendations by advisory services and extension programs, simulated prices from an efficient market are used to compare performance of marketing practices over the long run and in individual 40-year periods. We find that an efficient market can generate diverse price behavior within finite samples, allowing for strategies that are inferior on average to perform relatively better, as frequently as half of the time in an average 40-year lifetime. Lifetime returns of strategies show considerable overlap, suggesting extremely low confidence in recommendations made based on short samples.
Tipo: Journal Article
Palavras-chave: Commodity storage model; Efficient market; Finite sample; Grain marketing; Long run; Rational expectations; Simulation; Crop Production/Industries; Marketing.
Ano: 2007
URL: http://purl.umn.edu/8598

FORWARD SHIPPING OPTIONS FOR GRAIN BY RAIL: A STRATEGIC RISK ANALYSIS; SUMMARY
Provedor de dados: 31
Autores: Priewe,   Steven R.; Wilson,   William W.
Grain hauling railroads began offering shipping alternatives in the late 1980s that have made transportation decisions more strategic. Shippers now confront alternatives ranging from nearby and unguaranteed ordering to various durations of forward and guaranteed shipment.  A dynamic stochastic simulation model was developed to analyze grain shipping and merchandising strategies that integrate these alternatives.
Tipo: Working or Discussion Paper
Palavras-chave: Railroads; Grain merchandising; Logistics; Simulation; Risk analysis; Crop Production/Industries.
Ano: 1997
URL: http://purl.umn.edu/23256

EMPLOYMENT IN BIOTECHNOLOGY IN GERMANY
Provedor de dados: 31
Autores: Menrad,   Klaus.
Paper prepared for presentation at the 8th ICABR International Conference on Agricultural Biotechnology: International Trade and Domestic Production Ravello (Italy), July 8 to 11th, 2004
Tipo: Conference Paper or Presentation
Palavras-chave: Biotechnology; Employment; Germany; Application industries; Simulation; Labor and Human Capital; E24; J21.
Ano: 2004
URL: http://purl.umn.edu/91012

Simulation of factors impeding water quality trading market performance
Provedor de dados: 31
Autores: Smith,   Craig M.; Peterson,   Jeffrey M.; Leatherman,   John C.
Over the past several decades, market-based approaches to natural resource management have received increased attention as a means to cost-effectively achieve environmental quality goals. Following on what has been hailed a success for reducing air pollution, water quality trading (WQT) has more recently been seen as the next great opportunity for reducing water pollution, especially for nutrient loading. Numerous trading programs have been pilot tested and/or adopted in states throughout the nation, with more than 70 programs now in operation (Breetz et al., 2004).  WQT would allow multiple contributors to surface water degradation to determine how best to meet an overarching collective goal related to pollution reduction. WQT takes advantage of...
Tipo: Conference Paper or Presentation
Palavras-chave: Water quality trading; Market based; Trading ratio; Information levels; Point source; Nonpoint source; Simulation; Environmental Economics and Policy; Resource /Energy Economics and Policy.
Ano: 2010
URL: http://purl.umn.edu/61125

The potential impact of markets for irrigation water in Italy and Spain: a comparison of two study areas
Provedor de dados: 31
Autores: Pujol,   Joan; Raggi,   Meri; Viaggi,   Davide.
The viability of irrigated systems in Southern Europe is closely linked to efficient institutional settings and water-allocation mechanisms. A significant, although not widely used, mechanism for water allocation is an intra-sectorial water market. The objective of this paper is to evaluate to what extent water markets may contribute to the improvement of the efficiency of water allocation and to the profitability of irrigated agriculture. The related issues of water allocation among farm types and farm specialisation are also addressed. The analysis is based on a basin-level linear programming model, comparing the situation with and without a market. It includes both fixed and variable transaction costs and estimates their combined effects on market...
Tipo: Journal Article
Palavras-chave: Water trading; Natural resource management; Simulation; Water management and policy; Linear programming; Irrigation; Resource /Energy Economics and Policy.
Ano: 2006
URL: http://purl.umn.edu/116971

Approximating optimal numerical solutions to bio-economic systems: How useful is simulation-optimization?
Provedor de dados: 31
Autores: Börner,   Jan; Higgins,   Steven Ian; Scheiter,   Simon; Kantelhardt,   Jochen.
For applications in agricultural economics, complex ecological systems are often oversimplified to the extent that ecologists rarely consider model results valid. Recursive optimization of complex systems represents an alternative, but requires strong assumptions regarding time preference and uncertainty. In this paper we explore the implications of merely approximating “true” optima of complex dynamic optimization problems using a technique called simulation-optimization. We develop a standard discrete renewable resource use problem and solve it numerically using both simulation-optimization and non-linear mathematical programming. We subsequently introduce non-linearity and uncertainty and graphically compare the performance of simulation-optimization...
Tipo: Conference Paper or Presentation
Palavras-chave: Optimal control; Simulation; Ecological economic systems; Interdisciplinary modeling; Environmental Economics and Policy; Research Methods/ Statistical Methods.
Ano: 2009
URL: http://purl.umn.edu/51407

Changes in Management Can Improve Returns from Cambodian Upland Crops
Provedor de dados: 31
Autores: Farquharson,   Robert J.; Sareth,   Chea; Somrangchittra,   Chapho; Martin,   Robert J.; Haigh,   Bruce M; Scott,   J. Fiona; Sopheap,   Ung.
Farming systems research for wet-season non-rice upland crops in Cambodia is being conducted with the overall aim of poverty reduction and food security for farmers in the Provinces of Battambang and Kampong Cham. Some of these cash crops exhibit low and variable incomes, especially when grown in the early wet season. Cambodian farmers may borrow money to buy crop inputs and often sell their produce to companies and traders from neighbouring countries, hence they are price takers. Some new crop technologies are evaluated which relate to soil and crop fertility management interacting with climatic factors. The DSSAT crop simulation model is used to predict outcomes from alternative management strategies. Bio-economic analyses are conducted to assess the...
Tipo: Conference Paper or Presentation
Palavras-chave: Upland crops; Cambodia; Technology; Economics; Simulation; Risk; Crop Production/Industries.
Ano: 2006
URL: http://purl.umn.edu/25602

The Farm Level Impacts of Replacing Current Farm Programs with a Whole Farm Revenue Program
Provedor de dados: 31
Autores: Raulston,   J. Marc; Richardson,   James W.; Outlaw,   Joe L.; Knapek,   George M.
This study evaluates the farm level economic impacts of implementing a whole farm revenue insurance program in lieu of current government program payments on agricultural producers in major production areas of the United States.  Realizing a multitude of viable options exist, this study demonstrates one way a whole farm revenue coverage program could work at the farm level and makes comparisons between the current baseline situation and alternative levels of revenue coverage implementation.
Tipo: Conference Paper or Presentation
Palavras-chave: Agricultural policy; Simulation; Representative farms; Government payments; Crop insurance; Revenue coverage; Agricultural and Food Policy.
Ano: 2011
URL: http://purl.umn.edu/98785

Agricultural Trade and Freshwater Resources
Provedor de dados: 31
Autores: Reimer,   Jeffrey J.
Approximately 75% of all water used by humans goes towards food production, much of which is traded internationally.  This study formally models how this works in the case of crop agriculture, making use of recent advances in international trade theory and new data on the productivity by which countries use water for crop agriculture.  The strength of the model lies in its ability to predict, when there is a shock to the system, how trade between pairs of specific countries changes for products that use water intensively.  In one application of the model, international trade in final products is shown to be a means for countries to deal with short- and long-run shocks to water resources that are too big for one country to handle by itself in isolation.  In...
Tipo: Presentation
Palavras-chave: Climate change; Simulation; Trade liberalization; Water; Agricultural and Food Policy; Crop Production/Industries; International Development; International Relations/Trade; Resource /Energy Economics and Policy; F11; F18; Q25; Q54.
Ano: 2012
URL: http://purl.umn.edu/123944

IMPACT OF NATIONAL GENERIC DAIRY ADVERTISING ON DAIRY MARKETS, 1984-95
Provedor de dados: 31
Autores: Kaiser,   Harry M.
The impacts of generic dairy advertising on retail, wholesale, and farm dairy markets are estimated in this study at the national level.  The results indicate that generic dairy advertising had a major impact on retail, wholesale, and farm markets for the dairy industry.  The main conclusion of the study is that farmers are receiving a high return on their investment in generic dairy advertising, i.e., an average rate of return of $3.40 for every dollar invested over the period 1984-95.  Moreover, the return on investment in advertising was higher in the most recent year, almost double the average for the previous 11 years.
Tipo: Journal Article
Palavras-chave: Dairy; Generic advertising; Industry econometric model; Simulation; Livestock Production/Industries; Marketing.
Ano: 1997
URL: http://purl.umn.edu/15059

A UNIFIED APPROACH TO SENSITIVITY ANALYSIS IN EQUILIBRIUM DISPLACEMENT MODELS: COMMENT
Provedor de dados: 31
Autores: Griffiths,   William E.; Zhao,   Xueyan.
It is pointed out that the Chebychev confidence intervals and maximum p-values advocated by Davis and Espinoza for sensitivity analysis of equilibrium displacement models are unnecessary. Desired probability intervals and probabilities can be accurately estimated without resorting to gross approximations.
Tipo: Working or Discussion Paper
Palavras-chave: Simulation; Probability distributions; Empirical quantiles; Research Methods/ Statistical Methods.
Ano: 1999
URL: http://purl.umn.edu/12950

Forecasting Wheat Output and Profits from Cropping Systems Using Simulation Models in Uasin Gishu, Kenya
Provedor de dados: 31
Autores: Nyangweso,   P.M.; Odmori,   Paul Okelo; Mapelu,   M.Z.; Odhiambo,   Mark O.
Simulation models have been used successfully to forecast productivity of cropping systems under various weather, management and policy scenarios. These models have helped farmers make efficient resource allocation decisions. However, in Kenya simulation models have not been used extensively and more specifically in modeling large scale cropping systems. The study aimed at forecasting productivity and profitability of wheat cropping systems in Uasin Gishu district, Kenya. Both primary and secondary data were used. Both time series and cross-sectional data for variables of interest were collected and complemented by a survey of 20 wheat farmers who were systematically selected to verify information obtained from secondary sources. Cropping Systems...
Tipo: Journal Article
Palavras-chave: Wheat; Cropping system; Simulation; Forecasting; Productivity; Profits; Crop Production/Industries.
Ano: 2010
URL: http://purl.umn.edu/95960

FORWARD SHIPPING OPTIONS FOR GRAIN BY RAIL: A STRATEGIC RISK ANALYSIS
Provedor de dados: 31
Autores: Priewe,   Steven R.; Wilson,   William W.
Grain hauling railroads began offering shipping alternatives in the late 1980s that have made transportation decisions more strategic. Shippers now confront alternatives ranging from nearby and unguaranteed ordering to various durations of forward and guaranteed shipment.  A dynamic stochastic simulation model was developed to analyze grain shipping and merchandising strategies that integrate these alternatives.
Tipo: Working or Discussion Paper
Palavras-chave: Railroads; Grain merchandising; Logistics; Simulation; Risk analysis; Crop Production/Industries; Marketing.
Ano: 1997
URL: http://purl.umn.edu/23414

Evaluating the Potential of Whole-Farm Insurance Over Crop-Specific Insurance Policies
Provedor de dados: 31
Autores: Bielza,   Maria; Garrido,   Alberto.
Since 1996, different formats of whole-farm insurance (WFI) have been launched in North America and Spain. Their rationale is to pool all farm's insurable risks into a single policy that provides cheaper coverage against the farm's revenue losses. We evaluate the gains of moving from a situation of full insurance coverage delivered by crop-specific policies to WFI. Based on the records of individual farmers gathered by the Spanish Agricultural Insurance Agency (ENESA), we select two representative farms in Valencia that have consistently purchased insurance during 1993-2004 for three crops (apricots, plums and wine grapes). WFI is designed to deliver exactly the same expected revenue than does the combined effects of three crop-specific multiple-peril...
Tipo: Conference Paper or Presentation
Palavras-chave: Agricultural insurance; Whole-farm insurance; Simulation; Crop risks; Spanish agriculture; Risk and Uncertainty; Q14; G; Q18.
Ano: 2006
URL: http://purl.umn.edu/25421

ESTIMATING THE EFFECTS OF FACTORS INFLUENCING GRID PRICING REVENUE
Provedor de dados: 31
Autores: Schroeder,   Ted C.; Coffey,   Brian K.; Brester,   Gary W.
Beef carcasses, carcass premiums, carcass discounts, and grain prices are simulated.  Random carcasses are priced according to random sets of market conditions defining a distribution of total and net revenues.  Sensitivity analysis is performed to determine the total effect on revenue and net revenue of managing any of the interrelated carcass traits.  Keywords: grid pricing, risk, simulation
Tipo: Conference Paper or Presentation
Palavras-chave: Grid pricing; Risk; Simulation; Livestock Production/Industries.
Ano: 2002
URL: http://purl.umn.edu/36604

The Effect of Changing Government Subsidy Programs: An Analysis of Revenue at the Farm level
Provedor de dados: 31
Autores: Coble,   Keith H.; Thomas,   Sarah E.; Miller,   J. Corey.
Producer revenue is simultaneously simulated for several hundred county-specific representative farms.  The effects of current and alternative commodity programs are analyzed.  In particular, two variations of revenue-triggered programs similar to plans proposed by the National Corn Growers Association are evaluated.
Tipo: Conference Paper or Presentation
Palavras-chave: Risk; Commodity policy; Simulation; Agricultural and Food Policy; Risk and Uncertainty; Q180.
Ano: 2007
URL: http://purl.umn.edu/34931

Evaluation of political control instruments for the Swiss alpine region
Provedor de dados: 31
Autores: Calabrese,   Chiara; Mack,   Gabriele.
This paper analyses different direct payments system for the Swiss alpine region based on the multi-agent model SWISSland. Moreover, the future demand and management of the alpine pastures are simulated under different scenarios until 2020. In the model, agents are representing existing summer farms and are able to interact with each other. The results imply that the current direct payment system for the Swiss alpine region is effective and able to maintain a stable development until 2020. Since the land management in the alpine region is the activity that provides public goods, it would be reasonable to enforce payments that maximize the area of summered land. A change to contributions coupled to the surfaces could achieve the desired management of the...
Tipo: Conference Paper or Presentation
Palavras-chave: Multi-agent models; Policy analysis; Simulation; Alpine region; Agricultural and Food Policy; C16; Q18.
Ano: 2011
URL: http://purl.umn.edu/99370

Public Goods, Hysteresis, and Underinvestment in Food Safety
Provedor de dados: 31
Autores: Richards,   Timothy J.; Nganje,   William E.; Acharya,   Ram N.
Despite the economic damage inflicted by a foodborne disease outbreak, firms at all points in the supply chain appear to be reluctant to invest in the necessary food safety technologies and practices. We argue that these investments are subject to both hysteretic and public good effects, and construct a theoretical model of food safety investment, calibrated to describe the 2006 E. coli outbreak in California spinach. Both effects are found to induce delays in food safety investments, but the public good effect dominates. We suggest a number of policy options that improve incentives to contribute to the public good.
Tipo: Journal Article
Palavras-chave: Food safety; Hysteresis; Investment; Public goods; Real options; Simulation; Food Security and Poverty.
Ano: 2009
URL: http://purl.umn.edu/57627

Standard and Shuffled Halton Sequences in a Mixed Logit Model
Provedor de dados: 31
Autores: Staus,   Alexander.
Modeling consumer choice in different areas has lead to an increase use of discrete choice models. Probit or Multinomial Logit Models are often the base of further empirical research of consumer choice. In some of these models the equations to solve have no closed-form expression. They include multi-dimensional integrals which can not be solved analytically. Simulation methods have been developed to approximate a solution for these integrals. This paper describes the Standard Halton sequence and a modification of it, the Shuffled Halton sequence. Both are simulation methods which can reduce computational effort compared to a random sequence. We compare the simulation methods in their coverage of the multi-dimensional area and in their estimation results...
Tipo: Working or Discussion Paper
Palavras-chave: Simulation; Mixed logit; Halton sequence; Consumer/Household Economics; Food Consumption/Nutrition/Food Safety; C15; C25.
Ano: 2008
URL: http://purl.umn.edu/93856

CLIMATE CHANGE SENSITIVITY ASSESSMENT ON UPPER MISSISSIPPI RIVER BASIN STREAMFLOWS USING SWAT
Provedor de dados: 31
Autores: Jha,   Manoj K.; Arnold,   Jeffrey G.; Gassman,   Philip W.; Gu,   Roy.
The Soil and Water Assessment Tool (SWAT) model was used to assess the impacts of potential future climate change on the hydrology of the Upper Mississippi River Basin (UMRB). Calibration and validation of SWAT were performed on a monthly basis for 1968-87 and 1988-97, respectively; R2 and Nash-Sutcliffe simulation efficiency (E) values computed for the monthly comparisons were 0.74 and 0.65 for the calibration period and 0.81 and 0.75 for the validation period. The impacts of eight 20-year (1971-90) scenarios were then analyzed, relative to a scenario baseline. A doubling of atmospheric CO2 concentrations was predicted to result in an average annual flow increase of 35 percent. An average annual flow decrease of 15 percent was estimated for a constant...
Tipo: Working or Discussion Paper
Palavras-chave: Climate change; Flow; Hydrology; Simulation; Spatial patterns; Watershed; Environmental Economics and Policy.
Ano: 2004
URL: http://purl.umn.edu/18419

IMPACTS OF WITHIN-FARM SOIL VARIABILITY ON NITROGEN POLLUTION CONTROL COSTS
Provedor de dados: 31
Autores: Vandyke,   Laura S.; Bosch,   Darrell J.; Pease,   James W.
The effects of considering variable within-farm soil runoff and leaching potential on costs of reducing nitrogen losses are analyzed for a Virginia dairy.  Manure applications may cause nitrogen losses through runoff and leaching because of factors such as uncertain nitrogen mineralization.  Farmers can reduce nitrogen control costs by applying manure on soils with less nitrogen loss potential.  Ignoring within-farm soil variability may result in overstating the farm's costs of reducing nitrogen losses.
Tipo: Journal Article
Palavras-chave: Economic costs; Linear programming; Manure; Nitrogen; Nutrient management; Simulation; Soil variability; Environmental Economics and Policy.
Ano: 1999
URL: http://purl.umn.edu/15139

Measurement of Farm Credit Risk: SUR Model and Simulation Approach
Provedor de dados: 31
Autores: Yan,   Yan; Barry,   Peter J.; Paulson,   Nicholas D.; Schnitkey,   Gary D.
The study addresses problems in measuring credit risk under the structure model, and then proposes a seemingly unrelated regression model (SUR) to predict farms’ ability in meeting their current and anticipated obligations in the next 12 months. The empirical model accounts for both the dependence structure and the dynamic feature of the structure model, and is used for estimating asset correlation using FBFM data for 1995-2004. Farm credit risk is then predicted by copula based simulation process with historical default rates as benchmark. Results are reported and compared to previous studies on farm default.
Tipo: Conference Paper or Presentation
Palavras-chave: Credit Risk Measurement; Seemingly Unrelated Regression Model; Simulation; Agribusiness; Agricultural Finance; Farm Management; Research Methods/ Statistical Methods; Risk and Uncertainty.
Ano: 2009
URL: http://purl.umn.edu/49222

AN EX ANTE ASSESSMENT OF INVESTMENTS IN TEXAS GRAPEFRUIT UNDER UNCERTAINTY
Provedor de dados: 31
Autores: Elmer,   Nicole A.; Thurow,   Amy Purvis; Johnson,   Jason L.; Rosson,   C. Parr, III.
The Dixit-Pindyck model was applied to examine the hypothesis that uncertainty associated with grapefruit production costs and returns is an important determinant of Texas grapefruit growers' investment behavior.  Freezes, price variability, and the effects of expanded trade were analyzed as risk factors.  An investment decision rule based on a net-present value calculation would approve a 25-year commitment to a 20-acre grapefruit grove, given a 6-percent discount rate.  The modified hurdle rate, calculated using an ex ante version of the Dixit-Pindyck model, is 24 percent.  The major source of the risk borne by Texas grapefruit investors is from freezes, rather than from expanded trade.
Tipo: Journal Article
Palavras-chave: Citrus; Ex ante analysis; Dixit-Pindyck model; Freezes; Investment; Simulation; Texas; Trade; Crop Production/Industries.
Ano: 2001
URL: http://purl.umn.edu/15451

Grain Sorghum International Trade: U.S.-Mexico Simulation and Estimation Model
Provedor de dados: 31
Autores: Liu,   Bing; Malaga,   Jaime E.
An econometric international supply/demand/trade simulation and forecast sorghum model in a partial equilibrium framework is built in this research paper to quantify the effects of key exogenous variables on the U.S.-Mexico sorghum trade. A forecast baseline is also established by using the validated model and values of exogenous variables provided by FAPRI to project the level of endogenous variables over the period of 2009 to 2017. Impacts of plausible alternative scenarios for key exogenous variables are simulated from 2009 to 2017.
Tipo: Conference Paper or Presentation
Palavras-chave: Sorghum; International Trade; Simulation; Estimation; International Relations/Trade.
Ano: 2010
URL: http://purl.umn.edu/56434

Machinery-Sharing Contractual Issues and Impacts on Cash Flows of Agribusinesses
Provedor de dados: 31
Autores: Wolfley,   Jared L.; Mjelde,   James W.; Klinefelter,   Danny A.; Salin,   Victoria.
Contractual arrangements for joint machinery ownership between independent agribusinesses are explored. A two-farm economic simulation model of locations in Texas, Colorado, and Montana is developed to provide insight associated with sharing combines. Important variables include combine size (efficiency), yield losses resulting from untimely access to equipment, the penalty structure for untimely delivery, and cost-sharing and depreciation deductions claimed between producers. Combine sharing is risk-reducing in most cases. The gains to both parties are lowest when harvesting periods overlap. While the value of sharing is positive under many scenarios, benefits from sharing are small relative to total farm revenue.
Tipo: Journal Article
Palavras-chave: Combines; Machinery sharing; Risk; Simulation; Agribusiness; Agricultural Finance.
Ano: 2011
URL: http://purl.umn.edu/105536

Power by simulation
Provedor de dados: 31
Autores: Feiveson,   A.H.
This paper describes how to write Stata programs to estimate the power of virtually any statistical test that Stata can perform. Examples given include the t test, Poisson regression, Cox regression, and the nonparametric rank-sum test.
Tipo: Journal Article
Palavras-chave: Power; Simulation; Random number generation; Postfile; Copula; Sample size; Research Methods/ Statistical Methods.
Ano: 2002
URL: http://purl.umn.edu/115955

THE EFFECT OF THE NEW SINGLE FARM PAYMENT IN IRRIGATED AGRICULTURE: THE CASE OF SPAIN
Provedor de dados: 31
Autores: Gracia,   Azucena; de Magistris,   Tiziana; Casado,   Jose Maria.
The aim of the paper is to provide an econometric, dynamic, multi-product and partial equilibrium model for the Spanish agriculture able to analyse the effects of the SFP and subsequent reforms in both the irrigated and non-irrigated cultivation. In the case of the EU Mediterranean countries, irrigated agriculture is very relevant because farmers in irrigated land get higher productivity and returns. However, irrigation is also the source of a number of environmental concerns, such as over-abstraction of water from subterranean aquifers, irrigation driven erosion, soil salinisation, etc.. The new decoupling direct payments from production will reduce many of the incentives to intensive production. The developed model is called Spanish Econometric...
Tipo: Conference Paper or Presentation
Palavras-chave: CAP reform; Partial equilibrium model; Policy modelling; Irrigated Agriculture; Simulation; Agricultural and Food Policy; Land Economics/Use; Research Methods/ Statistical Methods.
Ano: 2008
URL: http://purl.umn.edu/6590

PHOSPHORUS-BASED NUTRIENT MANAGEMENT PLANNING ON DAIRY/POULTRY FARMS: IMPLICATIONS FOR ECONOMIC AND ENVIRONMENTAL RISKS
Provedor de dados: 31
Autores: Yang,   Xiao; Bosch,   Darrell J.; Nordberg,   Tone; Wolfe,   Mary Leigh.
The effects of phosphorus (P)-based nutrient management plans on economic and environmental risks of dairy and dairy-poultry farms in Virginia were evaluated.  Phosphorus-based nutrient management plans can greatly reduce P runoff risk but also reduce farmers' returns.  P-based plans cause greater reductions in returns and P runoff on the dairy-poultry farm than on the dairy only farm.
Tipo: Conference Paper or Presentation
Palavras-chave: Nutrient runoff; Cost; Mathematical programming; Simulation; Watershed; Environmental Economics and Policy; Livestock Production/Industries.
Ano: 2000
URL: http://purl.umn.edu/21756

Forecasting the consumption effect of taxing foods containing saturated fat
Provedor de dados: 31
Autores: Hansen,   Aslak H.
The purpose of the current paper is to explain how one can forecast the effect of an elected tax on saturated fat on the demand for butter. The tax is to take affect from the first of January 2010 in Denmark. The tax is supposed to affect the consumption of saturated fat and especially high consuming households are of interest. Quantile regression is thus better suited than mean regression. Interest centre on at risk groups with larger consumption, but we are also interested in a simple measure that measure the total effect of the tax change, i.e. the unconditional quantile. The former can easily be obtained from the quantile regression while it is proposed to use simulations in the latter case. In mean regression a close form formula for calculating the...
Tipo: Conference Paper or Presentation
Palavras-chave: Quantile Regression; Simulation; Healthy Diet; Public Policy.; Agricultural and Food Policy.
Ano: 2009
URL: http://purl.umn.edu/58153

Location and Spatial Pricing in Agricultural Markets
Provedor de dados: 31
Autores: Graubner,   Marten; Balmann,   Alfons; Sexton,   Richard J.
Agricultural markets often feature significant transport costs and spatially distributed production and processing which causes spatial imperfect competition. Spatial economics considers the firms’ decisions regarding location and spatial price strategy separately, usually on the demand side, and under restrictive assumptions. Therefore, alternative approaches are needed to explain, e.g., the location of new ethanol plants in the U.S. at peripheral as well as at central locations and the observation of different spatial price strategies in the market. We use an agent-based simulation model to analyze location and spatial pricing in a general model under multi-firm competition, two-dimensional space, and a continuum of potential price strategies. The...
Tipo: Conference Paper or Presentation
Palavras-chave: Spatial competition; Location; Price discrimination; Oligopsony; Simulation; Industrial Organization; Research Methods/ Statistical Methods; C63; Q11; R32.
Ano: 2010
URL: http://purl.umn.edu/61225

Viability of the Raw Cotton Production in Spain After the Decoupling of the Subsidies
Provedor de dados: 31
Autores: Arriaza Balmón,   Manuel; Gomez-Limon,   Jose Antonio; Gonzalez,   Jose; Ruiz,   Pedro.
Considering the latest reform of the EU's Cotton Regulation of 29th April 2004, which will come into force in the 2006/07 season, we analyse its impact on the cotton production sector of Andalusia. The decoupling of subsidies implies that producers will be entitled to 65 percent of the amount received in the reference period (three years) irrespective of the crop chosen to grow. The remaining 35 percent (slightly higher) is paid as cotton are a payment. In this research, first from a survey carried out in 2004 we obtained six groups of producers using fact or analysis and cluster analysis. Then, based on this characterization, we assess the impact of two policy scenarios: (a) the implementation of the reform without any additional measures, and (b) the...
Tipo: Conference Paper or Presentation
Palavras-chave: Cotton; Spain; Mid-Term Reform; Simulation; Multi-Criteria Decision Making; Agricultural and Food Policy; Crop Production/Industries.
Ano: 2006
URL: http://purl.umn.edu/25445

THE POSSIBILITIES OF APPLYING HISTORIC SIMULATION FOR ASSESSING THE PROFITABILITY OF INVESTMENTS
Provedor de dados: 31
Autores: Peter,   Beata.
The above methods of assessment are based on different methodological and mathematical approaches; therefore, they yield slightly different results, which can be used to complement each other and thus gain a more complex picture about the risk of the investment. Calculating break-even points and sensitivity assessment are simple variance calculation methods with differing frameworks or backgrounds. The basis of decision is NPV, as the break even points of the various factors do not come complete with clearly defined rules and cut-off points for accepting or rejecting an investment. This is especially true for the dynamic payback period, which discriminates against long-term investments. Conclusions about the risk of the investment can be drawn if expected...
Tipo: Journal Article
Palavras-chave: Risk factors; Risk assessment methods; Simulation; Agricultural Finance; Financial Economics.
Ano: 2007
URL: http://purl.umn.edu/58906

Procurement Strategies to Improve Quality Consistency in Wheat Shipments
Provedor de dados: 31
Autores: Wilson,   William W.; Dahl,   Bruce L.
Consistency of functional characteristics in wheat is a concern confronting buyers and sellers. This research analyzes the cost and risk of different procurement strategies for importers. A stochastic simulation model is used to determine the probability of functional characteristics being satisfied subject to quality targets and costs for alternative purchase strategies. Stochastic efficiency was employed to identify purchase strategies that dominate others and to determine the extent of preference. As more specific characteristics are incorporated into a contract, results indicate that the probabilities of meeting end-use requirements increase
Tipo: Journal Article
Palavras-chave: Buying strategies; Costs; Functional characteristic tests; Location; Risks; Simulation; Stochastic efficiency; Variety; Crop Production/Industries; International Relations/Trade.
Ano: 2008
URL: http://purl.umn.edu/36708

Forecasting Demand for Rural Electric Cooperative Call Center
Provedor de dados: 31
Autores: Kim,   Taeyoon; Kenkel,   Philip L.; Brorsen,   B. Wade.
This research forecasts peak call volume to allow a centralized call center to minimize staffing costs. A Gaussian copula is used to capture the dependence among nonnormal distributions. Peak call volume can be easily and more accurately predicted using the marginal probability distribution with the copula function than without using a copula. The modeling approach allows simulating adding another cooperative. Ignoring the dependence that the copula includes, causes peak values to be underestimated.
Tipo: Conference Paper or Presentation
Palavras-chave: Call center data; Empirical distribution; Extreme value theory; Forecasting; Gamma distribution; Gaussian copula; Simulation; Agribusiness; Demand and Price Analysis; Research Methods/ Statistical Methods.
Ano: 2009
URL: http://purl.umn.edu/46809

Estructura de preferencias de los consumidores de vino y actitudes hacia los vinos con Denominacion de Origen. El caso de Castilla-La Mancha
Provedor de dados: 31
Autores: Bernabeu,   Rodolfo; Olmeda,   Miguel; Diaz,   Monica.
El trabajo ha cubierto un doble objetivo, por un lado se ha determinado la importancia relativa de los atributos del vino que influyen en la conformación de las preferencias de los consumidores de Castilla-La Mancha, y por otro se ha analizado la actitud de los consumidores hacia los vinos con certificación de Denominación de Origen (D.O.) más importantes de Castilla-La Mancha (D.O. La Mancha y D.O. Valdepeñas), con respecto al más conocido en el ámbito nacional (D.O. Rioja). Como resultado del primer objetivo, los atributos más relevantes son el precio, el color (tinto, blanco), la certificación y el origen, por este orden, y del segundo objetivo, se obtiene que la D.O. La Mancha y la D.O. Valdepeñas son percibidas como de vinos más baratos, de consumo...
Tipo: Journal Article
Palavras-chave: Designation of origin; Consumer behaviour; Conjoint Analysis; Simulation; Positioning brands; Consumer/Household Economics; M31; Q13.
Ano: 2005
URL: http://purl.umn.edu/28772

Analyses of Generic Dairy Advertising, 1984-97
Provedor de dados: 31
Autores: Blisard,   Noel; Blayney,   Donald P.; Chandran,   Ram; Allshouse,   Jane E.
Generic advertising raised fluid milk sales about 6.0 percent, or 18.1 billion pounds, between September 1984 and September 1997. Sales of cheese rose by about 6.8 billion pounds (milk equivalent) in the same period because of increased generic advertising. An assessment of 15 cents per hundredweight of milk sold commercially, mandated by the Dairy and Tobacco Adjustment Act of 1983, funded the advertising. Activities of the National Fluid Milk Processor Promotion Board also contributed to increased milk sales over the past year. Gross returns to dairy farmers between September 1984 and September 1997 were estimated to increase by $3.44 for each dollar spent on generic advertising.
Tipo: Report
Palavras-chave: Cheese; Fluid milk; Advertising; Demand; Entry; Exit; Distributed lag; Econometrics; Simulation; Elasticities; Milk Processor Education Program; Livestock Production/Industries; Marketing.
Ano: 1999
URL: http://purl.umn.edu/33554

Advanced Biofuel Production in Louisiana Sugar Mills: an Application of Real Options Analysis
Provedor de dados: 31
Autores: Darby,   Paul M.; Mark,   Tyler B.; Detre,   Joshua D.; Salassi,   Michael E.
In order to more fully study the risks and uncertainty involved in cellulosic ethanol production, we examine a simulated plant in South Louisiana using Real Options Analysis
Tipo: Conference Paper or Presentation
Palavras-chave: Real options; Risk; Uncertainty; Cellulosic ethanol; Energy cane; Sorghum; Bagasse; Simulation; Agribusiness; Agricultural Finance; Production Economics; Resource /Energy Economics and Policy; Risk and Uncertainty; Q42; Q14; Q16; D81; G31.
Ano: 2011
URL: http://purl.umn.edu/103747

Bio-ethanol Production from Wheat in the Winter Rainfall Region of South Africa: A Quantitative Risk Analysis
Provedor de dados: 31
Autores: Richardson,   James W.; Lemmer,   Wessel J.; Outlaw,   Joe L.
Contrary to developments in other parts of the world, South Africa has not developed a bio-ethanol industry. The objective was to quantify the risks and economic viability of a wheat based bio-ethanol plant in the winter rainfall region of South Africa. Monte Carlo simulation of a bio-ethanol plant was used to quantify the risk that investors will likely face. Under the Base scenario a 103 million liter bio-ethanol plant would not offer a reasonable chance of being economically viable. Alternative price enhancing policies were analyzed to determine policy changes needed to make a bio-ethanol plant economically viable in the region.
Tipo: Journal Article
Palavras-chave: Biofuels; Ethanol; Risk analysis; Simulation; Economic viability; Simetar; SERF; Crop Production/Industries; Resource /Energy Economics and Policy.
Ano: 2007
URL: http://purl.umn.edu/8192

Estimating the Fair Insurance Premium for Dungeness Crab Yields in the Western U.S. Coast
Provedor de dados: 31
Autores: Liu,   Chia-Lan; Richardson,   James W.; Leatham,   David J.
The Dungeness is a popular food and the most commercially important crab in the western states in the U.S. Like all agricultural production, the crab fisherman face yield risks and must manage these risks. In addition to weather risk, crab fisherman may experience low yields if the crabs are over fished in previous years. Farmers for many traditional agricultural crops can purchase crop insurance to insure against low yields. However, crab fishermen at this time do not have this option. The purpose of this paper is to estimate a fair insurance premium based on the historical yields of the Dungeness crab. This information can then be used in risk/return models for crab fishing to determine if it would be optimal for fisherman to purchase crop insurance. An...
Tipo: Conference Paper or Presentation
Palavras-chave: Dungeness Crab; Fair Insurance Premium; Simulation; Agricultural and Food Policy; Agricultural Finance; Risk and Uncertainty.
Ano: 2011
URL: http://purl.umn.edu/103424

Hedge Effectiveness Forecasting
Provedor de dados: 31
Autores: Dahlgran,   Roger A.; Ma,   Xudong.
This study focuses on hedging effectiveness defined as the proportionate price risk reduction created by hedging. By mathematical and simulation analysis we determine the following: (a) the regression R2 in the hedge ratio regression will generally overstate the amount of price risk reduction that can be achieved by hedging, (b) the properly computed hedging effectiveness in the hedge ratio regression will also generally overstate the amount of risk reduction that can be achieved by hedging, (c) the overstatement in (b) declines as the sample size increases, (d) application of estimated hedge ratios to non sample data results in an unbiased estimate of hedging effectiveness, (e) application of hedge ratios computed from small samples presents a significant...
Tipo: Conference Paper or Presentation
Palavras-chave: Out of sample; Post sample; Hedging; Effectiveness; Forecasts; Simulation; Agricultural Finance.
Ano: 2008
URL: http://purl.umn.edu/37604

Mitigating Cotton Revenue Risk Through Irrigation, Insurance, and Hedging
Provedor de dados: 31
Autores: Barham,   E. Hart Bise; Robinson,   John R.C.; Richardson,   James W.; Rister,   M. Edward.
This study focuses on managing cotton production and marketing risks using combinations of irrigation levels, put options (as price insurance), and crop insurance. Stochastic cotton yields and prices are used to simulate a whole-farm financial statement for a 1,000 acre furrow irrigated cotton farm in the Texas Lower Rio Grande Valley under 16 combinations of risk management strategies. Analyses for risk-averse decision makers indicate that multiple irrigations are preferred. The benefits to purchasing put options increase with yields, as they are more beneficial when higher yields are expected from applying more irrigation applications. Crop insurance is strongly preferred at lower irrigation levels.
Tipo: Journal Article
Palavras-chave: Cotton; Crop insurance; Irrigation; Options; Puts; Risk; Simulation; Stochastic efficiency with respect to a function; Farm Management; Risk and Uncertainty; D81; Q12; Q15.
Ano: 2011
URL: http://purl.umn.edu/117946

Planning the Sustainable Agro-fuel Supply Chain
Provedor de dados: 31
Autores: Rosa,   Franco.
The agricultural sector is receiving a great deal of attention for topics of general interest as the security, multifunctional activities, alternative uses of crops in food/feed/fuel, reduction in GHG (Green House Gas) emission, LCA (Life Cycle Assessment). The EU policies are directed to implement sustainable local agro-food systems, and the AFSC (agro-fuel supply chain) represent the central issue in planning agricultural commodities to be used for fuel production performed in a space-time dimension. In this paper it is presented a methodology of regional planning the AFSC supported by empirical evidences in the region FVG (Friuli Venezia Giulia). The reference crop is the Mais largely cultivated in this region and now used to satisfy food-feedstock-fuel...
Tipo: Presentation
Palavras-chave: Planning AFSC; Regional development plan; Multifunctional approach; Agri-food supply chain; Simulation; Resource /Energy Economics and Policy.
Ano: 2012
URL: http://purl.umn.edu/124130

Use of a Producer Survey to Reconcile Differences in Experiment Station Yield Estimates
Provedor de dados: 31
Autores: Duke,   Jason C.; Epplin,   Francis M.
Average producer practice reveals that the expected returns are greater from dual-purpose wheat grown for both forage and grain than for grain-only wheat. Variety trials report an 11 bushel per acre yield advantage and hence economic advantage for grain-only. Research was conducted to reconcile the inconsistency.
Tipo: Conference Paper or Presentation
Palavras-chave: Direct elicitation method; Dual-purpose; Simulation; Stocker steers; Survey; Triangular distribution; Wheat; Farm Management; Livestock Production/Industries; Q10; Q12.
Ano: 2010
URL: http://purl.umn.edu/56436

A Risk Analysis of Converting CRP Acres to a Wheat-Sorghum-Fallow Rotation
Provedor de dados: 31
Autores: Williams,   Jeffery R.; Llewelyn,   Richard V.; Pendell,   Dustin L.; Schlegel,   Alan J.; Troy,   Dumler.
This study examines the economic potential of producing a wheat (Triticum aesitivum) and grain sorghum (Sorghum bicolor (L.) Moench) rotation with three different tillage strategies compared to the Conservation Reserve Program (CRP) in a semi-arid region.  This research uses stochastic efficiency with respect to a function (SERF) to determine the preferred management strategies under various risk preferences and utility-weighted certainty equivalent risk premiums.  Yields, input rates, and field operations from an experimental field in western Kansas are used to calculate net returns for each tillage strategy.  Although current net returns to crop production using reduced tillage and no-tillage strategies are higher than CRP, risk analysis indicates CRP...
Tipo: Conference Paper or Presentation
Palavras-chave: Conservation Reserve Program; Conservation tillage; Simulation; Sorghum; Wheat; Risk; Agricultural and Food Policy; Crop Production/Industries; Farm Management; Land Economics/Use; Risk and Uncertainty.
Ano: 2008
URL: http://purl.umn.edu/45985

Impact of Fuel Price Increases on Texas Crops
Provedor de dados: 31
Autores: Eggerman,   Chris R.; McMahon,   Sarah A.; Richardson,   James W.; Outlaw,   Joe L.
Replaced with revised version of paper 02/02/06.
Tipo: Conference Paper or Presentation
Palavras-chave: Crop model; Simulation; Input-output model; Resource /Energy Economics and Policy; C53; Q10.
Ano: 2006
URL: http://purl.umn.edu/35303

IN-PATIENT FLOW ANALYSIS USING PROMODEL (TM) SIMULATION PACKAGE
Provedor de dados: 31
Autores: Elbeyli,   Sema; Krishnan,   Palaniappa.
This paper emphasizes the basic modeling approach of general in-patient flow in a major hospital in the East Coast region. Simulation was used to analyze the inpatient flow. The first objective of this study was to determine the bottlenecks for in-in-patient flow. In order to understand the general in-patient flow, some emphasis was also given to the other units such as Medical-Surgical, Telemetry, Intensive Care Units (ICU), etc. Second objective was to study the impact of bed availability on the waiting time of admitted patients in ED before being transferred to assigned beds in other units of the hospital. A preliminary model was developed and validated based on the data collected for the selected time periods (busy four months). Different “what-if”...
Tipo: Working or Discussion Paper
Palavras-chave: Simulation; In-patient flow; Health science; Health Economics and Policy.
Ano: 2000
URL: http://purl.umn.edu/15827

Maximum likelihood estimation of generalized linear models with covariate measurement error
Provedor de dados: 31
Autores: Rabe-Hesketh,   Sophia; Skrondal,   Anders; Pickles,   Andrew.
Generalized linear models with covariate measurement error can be estimated by maximum likelihood using gllamm, a program that fits a large class of multilevel latent variable models (Rabe-Hesketh, Skrondal, and Pickles 2004). The program uses adaptive quadrature to evaluate the log likelihood, producing more reliable results than many other methods (Rabe-Hesketh, Skrondal, and Pickles 2002). For a single covariate measured with error (assuming a classical measurement model), we describe a “wrapper” command, cme, that calls gllamm to estimate the model. The wrapper makes life easy for the user by accepting a simple syntax and data structure and producing extended and easily interpretable output. The commands for preparing the data and running gllamm can...
Tipo: Journal Article
Palavras-chave: Covariate measurement error; Measurement model; Congeneric measurement model; Factor model; Adaptive quadrature; Nonparametric maximum likelihood; NPMLE; Latent class model; Empirical Bayes; Simulation; Wrapper; Sensitivity analysis; Gllamm; Cme; Research Methods/ Statistical Methods.
Ano: 2003
URL: http://purl.umn.edu/116185

WELFARE EFFECTS OF ECO-LABEL PROLIFERATION: TOO MUCH OF A GOOD THING?
Provedor de dados: 31
Autores: Lohr,   Luanne.
Given that existing food eco-labels are still not well defined in consumers' experience, there is potential for new labels to generate more confusion.  Consumers incur fixed costs to learn about a label's meaning.  Market shares for existing certifications may be eroded by perceptions that new products are good substitutes for them.  The eco-label certifier must respond with information that reduces these costs or lose consumer and producer confidence in the label.  Using a model of spatial competition in attribute space, the effect of search costs and educational expenditures on market share and price for competing certifiers is simulated.  The results show that educational spending and/or improvements in efficiency of educational spending increase market...
Tipo: Working or Discussion Paper
Palavras-chave: Eco-labeling; Market segmentation; Organic agriculture; Product differentiation; Search costs; Simulation; Spatial competition; Environmental Economics and Policy; Marketing.
Ano: 1998
URL: http://purl.umn.edu/16642

VALUE OF SOCIAL CAPITAL TO MID-SIZED NORTHERN PLAINS FARMS
Provedor de dados: 31
Autores: Gustafson,   Cole R.
As farms increase in size, operators often face the difficult decision of remaining loyal to local merchants or obtaining volume discounts from more distant input suppliers.  When farmers bypass local merchants and buy inputs in volume from a wholesaler, they often realize a price discount but forego many services including credit forebearance.  In essence, when farmers buy locally, they pay higher prices, which decreases profits and increases financial risk, but generates social capital which can be drawn upon during periods of economic adversity later in the form of credit forebearance.   A theoretical model of farm financial risk evaluates borrower behavior in light of cash flow constraints, volume discounts, and social capital.  Monte-carlo simulation...
Tipo: Working or Discussion Paper
Palavras-chave: Social; Capital; Financial risk; Simulation; Stochastic; Farm Management; Institutional and Behavioral Economics.
Ano: 2004
URL: http://purl.umn.edu/23677

RISK AND SITE FACTORS AFFECTING POTENTIAL NITROGEN DELIVERY IN THE VIRGINIA COASTAL PLAIN
Provedor de dados: 31
Autores: Peng,   Wei; Bosch,   Darrell J.
The effects of cropland slope, distance to surface water, farmers' risk attitudes, and farmers' nitrogen (N) fertilizer applications on potential N delivery to streams and costs of reducing N delivery were evaluated for a representative Virginia peanut-cotton farm.  Target MOTAD and generalized stochastic dominance were used to select preferred plans for different levels of risk aversion.  Costs of reducing N delivery were lower on farms where fields were located close to surface water, where N was overapplied relative to extension fertilizer recommendations, and where the operator was risk averse.  Cropland slope had less effect on cost of reducing N delivery relative to other factors.
Tipo: Journal Article
Palavras-chave: Cost; Nonpoint source pollution; Risk programming; Simulation; Stochastic dominance; Targeting; Environmental Economics and Policy.
Ano: 2001
URL: http://purl.umn.edu/15287

Risk-Adjusted Comparison of Conservation Reserve Program Payments Versus Production Payments for a Corn-Soybean Farmer
Provedor de dados: 31
Autores: Ibendahl,   Gregory A.
Conservation reserve program (CRP) payments amount to several billion dollars annually.  Payments are allocated to both remove land from production and to help farmers pay for conservation improvements.  However, research examining whether farmers increase their utility with CRPs is limited.  This paper uses simulation analysis and certainty equivalents to compare farming income to payments under the CRP.  Farming income is a combination of crop production and government payments as specified in the 2002 Farm Bill.  This analysis focuses on farms in three different counties in Kentucky.  Results indicate that CRPs are good choices for many farmers.
Tipo: Journal Article
Palavras-chave: Certainty equivalents; Conservation; CRP; Government payments; Risk; Simulation; Q15; Q18; Q16; C15.
Ano: 2004
URL: http://purl.umn.edu/43391

OPTIMIZING COMPLEX BIOECONOMIC SIMULATIONS USING AN EFFICIENT SEARCH HEURISTIC
Provedor de dados: 31
Autores: Kazmierczak,   Richard F., Jr.
For simulation to be truly useful for investigating many problems in agricultural economics, non-simplifying optimization techniques need to be employed.  General methods for simulation optimization that do not inhibit system characterization or analysis are available, and they would appear to provide much of the mathematical and optimizing rigor demanded by economists.  This paper describes the theory and algorithm of a robust and efficient simulation optimization approach, the Complex Method.  An example of implementing the algorithm is illustrated using a pest management problem.
Tipo: Working or Discussion Paper
Palavras-chave: Simulation; Optimization; Complex Method; Hill-climbing; Research Methods/ Statistical Methods.
Ano: 1996
URL: http://purl.umn.edu/31661

Entry, Exit, and Structural Change in Pennsylvania's Dairy Sector
Provedor de dados: 31
Autores: Stokes,   Jeffrey R.
Data on the number of Pennsylvania dairy farms by size category are analyzed in a Markov chain setting to determine factors affecting entry, exit, expansion, and contraction within the sector. Milk prices, milk price volatility, land prices, policy, and cow productivity all impact structural change in Pennsylvania's dairy sector. Stochastic simulation analysis suggests that the number of dairy farms in Pennsylvania will likely fall by only 2.0 percent to 2.5 percent annually over the next 20 years, indicating that dairy farming in Pennsylvania is likely to be a significant enterprise for the state in the foreseeable future.
Tipo: Journal Article
Palavras-chave: Dairy; Maximum entropy; Farm size; Markov chain; Simulation; Farm Management; Industrial Organization.
Ano: 2006
URL: http://purl.umn.edu/10218

Strategies for the Agro-food Sector
Provedor de dados: 31
Autores: Rosa,   Franco.
The agro-food sector is receiving a great deal of attention for topics of general interest as the food quality, security and safety, alternative uses of crops in food/feed/fuel, growing concern for GHG (Green House Gas) emission, LCA (Life Cycle Assessment), energy consumption. In the EU policies directed to implement sustainable local agro-food systems, the AFSC (agro-food supply chain) is emerging as the central issue in planning integrated farm-food activities performed in a space-time dimension. In this paper it is presented a methodology of regional planning the AFSC supported by empirical evidences about the region FVG (Friuli Venezia Giulia). The reference product is the Mais a crop largely cultivated in the region. A composite information system is...
Tipo: Presentation
Palavras-chave: Planning procedure; Regional development plan; Multifunctional approach; Agri-food supply chain; Simulation; Agribusiness; Farm Management; Food Consumption/Nutrition/Food Safety.
Ano: 2011
URL: http://purl.umn.edu/122023

An Economic Risk Analysis of No-till Management for the Rice-Soybean Rotation System used in Arkansas
Provedor de dados: 31
Autores: Hristovska,   Tatjana; Watkins,   K. Bradley; Anders,   Merle M.
Arkansas is the top domestic rice producer, representing nearly half of total U.S. rice production. Sediment is one of the major pollutants in rice producing areas of Arkansas. In order to mitigate this problem no-tillage management is often recommended. No-tillage is not well understood by farmers who believe that no-till is less profitable due to lower yields offsetting cost savings. This study evaluates the profitability and variability of no-till in the typical rice-soybean rotation used in Arkansas rice production. Crop yields, prices and prices for key production inputs (fuel and fertilizer) are simulated for the rotation, and net return distributions for rice, soybean and the two-year rotation are evaluated for no-till and conventional till using...
Tipo: Presentation
Palavras-chave: Simulation; Rice-soybean; No tillage-profitability; Risk analysis; Environmental Economics and Policy; Farm Management; Resource /Energy Economics and Policy.
Ano: 2012
URL: http://purl.umn.edu/119676

Hedging Price Risk in the Presence of Crop Yield and Revenue Insurance
Provedor de dados: 31
Autores: Mahul,   Olivier.
The demand for hedging against price uncertainty in the presence of crop yield and revenue insurance contracts is examined for two French wheat farms. The rationale for the use of options in addition to futures is first highlighted through the characterization of the first-best hedging strategy in the expected utility framework. It is then illustrated using numerical simulations. The presence of options is shown to allow the insured producer to adopt a more speculative position on the futures market. Futures are shown to be performing, in terms of willingness to receive. Options are weakly performing when futures markets are unbiased, while they are more performing when futures markets are biased.
Tipo: Conference Paper or Presentation
Palavras-chave: Crop insurance; Hedging; Producer welfare; Simulation; Risk and Uncertainty.
Ano: 2002
URL: http://purl.umn.edu/24881

Risk Classification in Animal Disease Prevention: Who Benefits from Differentiated Policy?
Provedor de dados: 31
Autores: Niemi,   Jarkko K.; Lyytikainen,   Tapani; Sahlstrom,   Leena; Virtanen,   Terhi; Lehtonen,   Heikki.
Risk classification of livestock farms can help stakeholders design and implement risk management measures according to the possessed risk. Our goal is to examine how differently pig farms may contribute to the societal costs of an animal disease outbreak, how valuable this information is to different stakeholders, and how it can be used to target risk management measures. We show that the costs of an outbreak starting from a certain farm can be quantified for the entire sector using bio-economic models. In further studies, this quantified risk can be differentiated so that farms and slaughterhouses internalise the full cost of risk in production decisions and inhibit animal densities, animal contact structures or other characteristics which pose a threat...
Tipo: Conference Paper or Presentation
Palavras-chave: Risk classification; Animal disease; Simulation; Dynamic programming; Partial-equilibrium; Losses; Agricultural and Food Policy; Agricultural Finance; Livestock Production/Industries; Risk and Uncertainty.
Ano: 2009
URL: http://purl.umn.edu/49307

Private Decisions and Public Goods: Trade-Offs in the Conservation Programs in the New Farm Bill: Discussion
Provedor de dados: 31
Autores: Davis,   Todd D.
The 2002 Farm Bill creates several opportunities for landowners to adopt management practices that protect and improve soil and water quality.  Landowners considering enrollment in conservation programs must compare the monetary and nonmonetary costs and benefits from removing land from production agriculture.  The overall purpose of this invited paper session was to improve the understanding of the factors affecting a landowner’s decision to enroll in conservation programs.  Papers addressed the environmental benefits of conservation programs and compared the returns to enrolling in conservation programs to the returns from production agriculture.
Tipo: Journal Article
Palavras-chave: Certainty equivalents; Conservation; Econometrics; Government payments; Risk; Simulation; Q18; Q16; C15; C31.
Ano: 2004
URL: http://purl.umn.edu/43417

Agent-Based Modelling and Sensitivity Analysis by Experimental Design and Metamodelling: An Application to Modelling Regional Structural Change
Provedor de dados: 31
Autores: Happe,   Kathrin.
This paper presents the application of the sensitivity analysis techniques Design of Experiments (DOE) and metamodelling to the agent-based model AgriPoliS, which is a spatial and dynamic simulation model of regional structural change. DOE and metamodelling provide a more systematic analysis of results of complex simulation models. When summarising the results, it becomes clear that interest rates, technical change and managerial ability influence average economic land rent the most.
Tipo: Conference Paper or Presentation
Palavras-chave: Simulation; Design of experiments; Metamodelling; Structural change; Research and Development/Tech Change/Emerging Technologies; C9; C15.
Ano: 2005
URL: http://purl.umn.edu/24464

Optimization of the sampling scheme for maps of physical and chemical properties estimated by kriging
Provedor de dados: 90
Autores: Pereira,Gener Tadeu; Souza,Zigomar Menezes de; Teixeira,Daniel De Bortoli; Montanari,Rafael; Marques Júnior,José.
The sampling scheme is essential in the investigation of the spatial variability of soil properties in Soil Science studies. The high costs of sampling schemes optimized with additional sampling points for each physical and chemical soil property, prevent their use in precision agriculture. The purpose of this study was to obtain an optimal sampling scheme for physical and chemical property sets and investigate its effect on the quality of soil sampling. Soil was sampled on a 42-ha area, with 206 geo-referenced points arranged in a regular grid spaced 50 m from each other, in a depth range of 0.00-0.20 m. In order to obtain an optimal sampling scheme for every physical and chemical property, a sample grid, a medium-scale variogram and the extended Spatial...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Geostatistics; Sugar cane.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000500002

Biophysical and economic models for assessing impacts of change on grazingland ecosystems
Provedor de dados: 91
Autores: Souza Neto,José de; Conner,James R.; Stuth,Jerry W.
PHYGROW, a hydrologic-based forage simulation model, was parameterized to represent a typical South Texas ranch engaged in the production of cattle and meat goats with an indigenous population of white-tailed deer. Forage production and associated stocking rates for two cattle:goat ratios were simulated with POPMIX for 20 years. Two ten-year weather scenarios, one representing normal conditions (30% drought years) and one representing dryer weather conditions (50% drought years) were analyzed. Management decision rules (ASPC) were developed for the region to produce estimates of annual animal production and operating costs for the enterprises on each of the four scenarios. These performance and cost data were then used as input into FLIPSIM, a firm level...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Model integration; Economic impacts; Grazingland ecosystems; Management strategies.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662001000100025

Soil water balance simulated by CROPGRO-Drybean model for edaphoclimatic conditions in Maringá
Provedor de dados: 91
Autores: Dallacort,Rivanildo; Freitas,Paulo S. L. de; Faria,Rogério T. de; Gonçalves,Antonio C. A.; Jácome,Aleksandra G.; Rezende,Roberto.
The performance of the CROPGRO-Drybeans model for the prediction of soil water balance, as well as growth components and bean crop yield, was assessed using data from two field experiments conducted at the State University of Maringá Irrigation Technical Center, Paraná - Brazil, (latitude 23º27'S, longitude 51º57' and altitude 542 m), during the 2005 and 2006 growing season. The model simulations correlated well with measured soil moisture (r &gt; 0.7) for both experiments. However, there were high discrepancies between measured and simulated soil moisture values on the days after rainfall. In addition, it was found that the model exaggerates the effect of water stress during the flowering phase, which leds to underprediction (19 and 29%) of crop yield.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Water stress; Soil moisture; Simulation.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662010000400002

Nitrogen efficiency in wheat yield through the biopolymer hydrogel
Provedor de dados: 91
Autores: Mamann,Ângela T. W De; Silva,José A. G. da; Scremin,Osmar B.; Mantai,Rubia D.; Scremin,Ari H.; Dornelles,Eldair F.
ABSTRACT Nitrogen use efficiency in wheat biomass and grain yields can be favored by the biopolymer hydrogel. The objective of the study was to analyze the use of the biopolymer hydrogel applied to the seed in the optimization of fertilizer-N on wheat biomass and grain yields, under different conditions of agricultural year and succession systems of high and reduced release of residual-N. In the study, two experiments were conducted, with different farming systems, soybean/wheat and maize/wheat, one to quantify the biomass yield rate and the other to determine grain yield. The experiments were conducted in the years 2014 and 2015, in a randomized block design with four replicates in a 4 x 4 factorial scheme, corresponding to hydrogel doses (0, 30, 60 and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Triticum aestivum; Simulation; Farming systems; Water stress.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017001000697

Water distribution from medium-size sprinkler in solid set sprinkler systems
Provedor de dados: 91
Autores: Prado,Giuliani do.
ABSTRACT The study aimed to evaluate the water distribution from a medium-size sprinkler working in solid set sprinkler systems. Water distribution radial curves from the sprinkler operating under four nozzle diameter combinations (4.0 x 4.6; 5.0 x 4.6; 6.2 x 4.6 and; 7.1 x 4.6 mm) and four working pressures (196; 245; 294 and 343 kPa) were evaluated on the sprinkler test bench of the State University of Maringá, in Cidade Gaúcha, Paraná, Brazil. The sixteen water distribution curves were normalized and subjected to clustering analysis (K-Means algorithm), identifying the occurrence of normalized distribution curves with three different geometric shapes. A computer algorithm, in Visual Basic for Applications in Excel spreadsheet, was developed to simulate...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Distribution curve; Simulation; Distribution uniformity.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000300195

Base temperature and simulation model for nodes appearance in cape gooseberry (Physalis peruviana L.)
Provedor de dados: 94
Autores: Salazar,Melba Ruth; Jones,James W.; Chaves,Bernardo; Cooman,Alexander; Fischer,Gerhard.
Data was analyzed on development of the solanaceen fruit crop Cape gooseberry to evaluate how well a classical thermal time model could describe node appearance in different environments. The data used in the analysis were obtained from experiments conducted in Colombia in open fields and greenhouse condition at two locations with different climate. An empirical, non linear segmented model was used to estimate the base temperature and to parameterize the model for simulation of node appearance vs. time. The base temperature (Tb) used to calculate the thermal time (TT, ºCd) for node appearance was estimated to be 6.29 ºC. The slope of the first linear segment was 0.023 nodes per TT and 0.008 for the second linear segment. The time at which the slope of node...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Nodes; Simulation; Thermal time; Base temperature; Cape gooseberry.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452008000400004

Ant colony algorithm for analysis of gene interaction in high-dimensional association data
Provedor de dados: 96
Autores: Rekaya,Romdhane; Robbins,Kelly.
In recent years there has been much focus on the use of single nucleotide polymorphism (SNP) fine genome mapping to identify causative mutations for traits of interest; however, many studies focus only on the marginal effects of markers, ignoring potential gene interactions. Simulation studies have show that this approach may not be powerful enough to detect important loci when gene interactions are present. While several studies have examined potential gene interaction, they tend to focus on a small number of SNP markers. Given the prohibitive computation cost of modeling interactions in studies involving a large number SNP, methods need to be develop that can account for potential gene interactions in a computationally efficient manner. This study adopts...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Genome; Simulation; SNP.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982009001300011

Turix, a dynamic mechanistic model for feed evaluation
Provedor de dados: 96
Autores: Vargas-Villamil,Luis Manuel; Ku-Vera,Juan Carlos; Vargas-Villamil,Felipe; Medina-Peralta,Salvador; Avila-Vales,Eric José; Aranda-Ibañez,Emilio Manuel; Avendaño-Reyes,Leonel.
The objective of this study was to use the Turix model (a new mechanistic dynamic model that can be used for feed evaluation under tropical conditions), along with in situ and in vitro sugar cane experimental data from a previous study, to evaluate sugar cane kinetics through estimation of three parameters associated with ruminal bacterial growth: kM,SmL, the substrate uptake; kLM, the bacterial growth from intermediate metabolite; and Y VFAP,FS, the products related to volatile fatty acid yield. Values of these parameters for the whole sugar cane and its neutral detergent fiber (NDF) and acid detergent fiber (ADF) fractions were: a) kM, SmL, 16.20, 50.47 and 21.97 mL h-1 (mg M)-1 ; b) kLM, 96.00, 543.00 and 1,680.00 h-1 ; and, 1.02, 0.40 and 0.23 g g-1 ,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Model fitting; Parameter estimation; Ruminant; Simulation; Sugar cane.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982013000400009

Simulation of Holstein and Jersey profitability by varying milk price payment system
Provedor de dados: 96
Autores: Cunha,Daniel de Noronha Figueiredo Vieira da; Pereira,José Carlos; Campos,Oriel Fajardo de; Gomes,Sebastião Teixeira; Braga,José Luis; Martuscello,Janaina Azevedo.
The objective of the study was to compare through simulation Holstein and Jersey breed herds, considering the farm size, zootechnical and economic indexes and profitability of the activity, by using different systems of bonus payment for milk price based in percentage of fat and protein in the milk. The comparisons were made, initially, disregarding the bonus payment for milk price based on the increase in the fat and protein percentage in milk. After that, the profitability of the activity was compared considering bonus payment for milk price of the Jersey breed herd, for each unit increment in fat and protein percentage in milk above those obtained with the Holstein breed herd. Finally, the profitability of the activity was compared by using the bonus...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dairy cattle; Milk fat; Milk protein modeling; Simulation.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010000400028

Models of protein and amino acid requirements for cattle
Provedor de dados: 96
Autores: Tedeschi,Luis Orlindo; Fox,Danny Gene; Fonseca,Mozart Alves; Cavalcanti,Luigi Francis Lima.
Protein supply and requirements by ruminants have been studied for more than a century. These studies led to the accumulation of lots of scientific information about digestion and metabolism of protein by ruminants as well as the characterization of the dietary protein in order to maximize animal performance. During the 1980s and 1990s, when computers became more accessible and powerful, scientists began to conceptualize and develop mathematical nutrition models, and to program them into computers to assist with ration balancing and formulation for domesticated ruminants, specifically dairy and beef cattle. The most commonly known nutrition models developed during this period were the National Research Council (NRC) in the United States, Agricultural...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Modeling; Nutrition; Prediction; Ruminants; Simulation.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982015000300109

Endogamy and genetic variability in selective mating using distribution of extremes
Provedor de dados: 96
Autores: Jangarelli,Marcelo; Euclydes,Ricardo Frederico.
The objective of this study was to evaluate selective mating using distribution of extremes, among other mating strategies, on its ability to decrease the endogamy and the loss of genetic variability. The genetic simulation system (Genesys) was used to simulate two genomes (each one with a single characteristic whose distinction was the value of heritability) and the base and original populations. Each initial population was submitted to assisted selection by markers for ten consecutive generations. For evaluation of strategies, the estimated parameters were phenotypic value, endogamy and additive genetic variance, in different family sizes, for both characteristics. In all scenarios combining heritability and family sizes, the selective mating was...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Additive genetic variance; Selection assisted by markers; Selective genotyping; Simulation.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982012000500010

A Mathematical model for the cold storage of agricultural products
Provedor de dados: 124
Autores: Meneghetti,Carlos Renato; Tizzei,Alexandre; Cappelli,Nelson Luis; Umezu,Claudio Kiyoshi; Bezzon,Guilherme.
Studies of control strategies for refrigeration systems observe, among other variables, the dynamic behavior of temperature and the consumption of electrical energy. Aiming to contribute to these studies, this work presents the proposal and validation of a mathematical model for the cooling system of a cold-storage unit. The model approximates the dynamics and interdependence of the variables, to first-order systems with time delay and the summation of effects. The input variables available are the frequency of compressor activation and the thermal load imposed on the unit, and as output variables, the air temperature both at the evaporator inlet and at the centre of the chamber, as well as the electrical power consumed by the compressor. The results...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Variable rotation; Simulation; Agricultural products-storage; Electrical energy-consumption.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902013000200010

Principles of crop modelling and simulation: II. the implications of the objective in model development
Provedor de dados: 63
Autores: Dourado-Neto,D.; Teruel,D.A.; Reichardt,K.; Nielsen,D.R.; Frizzone,J. A.; Bacchi,O.O.S.
With the purpose of presenting to scientists the implications of the objective in model development and a basic vision of modeling, with its potential applications and limitations in agriculture, an integration of crop modeling professionals with agricultural professionals is suggested. Models mean modernization of the information, of the measurement process and of an efficient way to learn more about complex systems. They are one of the best mechanisms of transforming information in useful knowledge and of transferring this knowledge to others. One of the problems that impede a larger progress in modeling is the lack of communication between modelers and a frequent appearance of modelers without a global vision of reality.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Crop modeling; Simulation.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161998000500009

Calibration and test of the cropgro-dry bean model for edaphoclimatic conditions in the savanas of Central Brazil
Provedor de dados: 63
Autores: Meireles,Elza Jacqueline Leite; Pereira,Antonio Roberto; Sentelhas,Paulo Cesar; Stone,Luis Fernando; Zimmermann,Francisco José Pfeilsticker.
Simulation models are important tools for the analysis of cultivated systems to estimate the performance of crops in different environments. The CROPGRO- model (DSSAT) was calibrated and validated using Carioca bean (Phaseolus vulgaris L.) to estimate yield and the development of the crop, sown in three row spacings (0.4, 0.5, and 0.6 m) and two fertilization rates (300 and 500 kg ha-1 of 4-30-16 N-P-K), in Santo Antônio de Goiás, GO, Brazil. To calibrate the model a combination of the genetic coefficients that characterize the phenology and morphology of the dry bean crop was used to obtain the best possible fit between predicted and observed anthesis and physiological maturity dates, leaf area index (LAI), total dry matter (TDM), yield components, and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: DSSAT; Dry bean; Simulation.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000400016

Choosing components in the additive main effect and multiplicative interaction (AMMI) models
Provedor de dados: 63
Autores: Dias,Carlos Tadeu dos Santos; Krzanowski,Wojtek Janusz.
The additive main effect and multiplicative interaction (AMMI) models allows analysts to detect interactions between rows and columns in a two-way table. However, there are many methods proposed in the literature to determine the number of multiplicative components to include in the AMMI model. These methods typically give different results for any particular data set, so the user needs some guidance as to which methods to use. In this paper we compare four commonly used methods using simulated data based on real experiments, and provide some general recommendations.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Two-way table; Principal components; Simulation.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000200009

Principles of crop modelling and simulation: III. modeling of root growth and other belowground processes, limitations of the models, and the future of modeling in agriculture
Provedor de dados: 63
Autores: DOURADO-NETO,D.; TERUEL,D. A.; REICHARDT,K.; NIELSEN,D.R.; FRIZZONE,J. A.; BACCHI,O.O.S.
The first models of temporal variation of root systems appeared over 20 years ago. The complex architectural geometry of root systems; the wide range in size and diameter and the rapid growth and decomposition of finest roots; the different physiological activity of roots of different ages; the complex microbial processes occurring at the root-soil interface; the symbiotic relationships in the rhizosphere; the variable soil environment (physical, chemical and biological) in which roots develop are the challenges of quantifying the root growth. The models are not simple mechanisms to archive information in order to produce forecasts. Modeling represents a better way of synthesizing knowledge about different components of a system, summarizing data, and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Crop modeling; Simulation.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161998000500010

Ballistic model to estimate microsprinkler droplet distribution
Provedor de dados: 63
Autores: Conceição,Marco Antônio Fonseca; Coelho,Rubens Duarte.
Experimental determination of microsprinkler droplets is difficult and time-consuming. This determination, however, could be achieved using ballistic models. The present study aimed to compare simulated and measured values of microsprinkler droplet diameters. Experimental measurements were made using the flour method, and simulations using a ballistic model adopted by the SIRIAS computational software. Drop diameters quantified in the experiment varied between 0.30 mm and 1.30 mm, while the simulated between 0.28 mm and 1.06 mm. The greatest differences between simulated and measured values were registered at the highest radial distance from the emitter. The model presented a performance classified as excellent for simulating microsprinkler drop...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Irrigation; Modeling; Simulation.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000400025

Neural networks for predicting breeding values and genetic gains
Provedor de dados: 63
Autores: Silva,Gabi Nunes; Tomaz,Rafael Simões; Sant'Anna,Isabela de Castro; Nascimento,Moysés; Bhering,Leonardo Lopes; Cruz,Cosme Damião.
Analysis using Artificial Neural Networks has been described as an approach in the decision-making process that, although incipient, has been reported as presenting high potential for use in animal and plant breeding. In this study, we introduce the procedure of using the expanded data set for training the network. Wealso proposed using statistical parameters to estimate the breeding value of genotypes in simulated scenarios, in addition to the mean phenotypic value in a feed-forward back propagation multilayer perceptron network. After evaluating artificial neural network configurations, our results showed its superiority to estimates based on linear models, as well as its applicability in the genetic value prediction process. The results further...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Genetic value; Statistics; Simulation; Artificial intelligence; Training strategy.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162014000600008

Principles of crop modeling and simulation: I. uses of mathematical models in agricultural science
Provedor de dados: 63
Autores: Dourado-Neto,D.; Teruel,D. A.; Reichardt,K.; Nielsen,D.R.; Frizzone,J. A.; Bacchi,O.O.S.
Modeling techniques applied to agriculture can be useful to define research priorities and understanding the basic interactions of the soil-plant-atmosphere system. Using a model to estimate the importance and the effect of certain parameters, a researcher can notice which factors can be most useful. The modeler should define his objectives before beginning his work and construct a model that fulfills the proposed objectives.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Crop modeling; Simulation.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161998000500008

Economic optimization of the number of recipients in bovine embryo transfer programs
Provedor de dados: 63
Autores: Beltrame,Renato Travassos; Barioni,Luis Gustavo; Maestri,Breno Dala; Quirino,Celia Raquel.
Purchase and maintenance of recipient females account for a large proportion of the costs and determine the number of calves that can be produced in an embryo transfer program. However, the large variability of embryo production by the donors and the need to purchase and synchronize the recipients before knowing the number of embryos collected make it difficult for the decision maker to identify the ideal number of recipient females to allocate. An ex-ante evaluation to determine the optimal number of recipient females was carried out through a sensitivity analysis for the ratio between the number of recipients and donors in a simulation model. The variability for the number of embryos collected was accounted for by applying the Monte Carlo simulation...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Monte Carlo; Mathematical model; Simulation; Cost estimation; Estrus synchronization.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162007000300002

Variance additivity of genetic populational parameter estimates obtained through bootstrapping
Provedor de dados: 63
Autores: Carlini-Garcia,Luciana Aparecida; Vencovsky,Roland; Coelho,Alexandre Siqueira Guedes.
Studying the genetic structure of natural populations is very important for conservation and use of the genetic variability available in nature. This research is related to genetic population structure analysis using real and simulated molecular data. To obtain variance estimates of pertinent parameters, the bootstrap resampling procedure was applied over different sampling units, namely: individuals within populations (I), populations (P), and individuals and populations simultaneously (I, P). The considered parameters were: the total fixation index (F or F IT), the fixation index within populations (f or F IS) and the divergence among populations or intrapopulation coancestry (theta or F ST). The aim of this research was to verify if the variance...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Population structure; Resampling; Molecular markers; Natural populations; Simulation.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000100015

Mathematical modeling and simulation of hourly precipitation through rectangular pulses - doi: 10.4025/actasciagron.v33i4.7052
Provedor de dados: 1
Autores: Uggioni, Edison; Universidade do Extremo Sul Catarinense; Back, Álvaro José; Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina; Vieira, Hamilton Justino; Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina.
The recorded historical series of precipitation are usually available for short periods of time and with many failures. The use of mathematical modeling to simulate rainfall is a tool used to circumvent this problem and to simulate the operation of water systems in different scenarios. The present study applies mathematical modeling to the hourly pluviometric precipitation data simulation.  A pluviographical data set from October 1980 to December 2007 was used in the study.  Precipitation data sets were obtained through daily pluviometric digitalization from the Meteorologic Station of Epagri at Urussanga, in southern Santa Catarina, Brazil (latitude 28º 31’ S and longitude 48º 19’ W).  To simulate the hourly rain series, the stochastic model was modified...
Tipo: Pesquisa aplicada
Palavras-chave: 5.03.02.00-0 Hydrology; Rainfall; Simulation; Probability; Stochastic models engenharia de Água e Solo Hydrology; Rainfall; Simulation; Probability; Stochastic models.
Ano: 2011
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/7052

Predição de valores genéticos utilizando inferência bayesiana e frequentista em dados simulados - doi: 10.4025/actascianimsci.v32i3.7862
Provedor de dados: 2
Autores: Carneiro Júnior, José Marques; Embrapa Acre; Assis, Giselle Mariano Lessa de; Embrapa Acre; Euclydes, Ricardo Frederico; Universidade Federal de Viçosa; Martins, Williane Maria de Oliveira; Embrapa Acre; Wolter, Priscila Ferreira; Embrapa Acre.
Dados simulados foram utilizados para comparar as metodologias Eblup e Bayesiana, em dados com homogeneidade de variâncias, heterogeneidade de variância genética e heterogeneidade de variância genética e ambiental. Para obtenção dessas estruturas foram feitos descartes estratégicos dos valores genéticos aditivos e ambientais de acordo com o tipo de heterogeneidade e o nível de variabilidade desejada (alta, média ou baixa), sendo utilizados dois tamanhos de população (grande e pequena). Para a metodologia Bayesiana foram utilizados três níveis de informação a priori: não informativo, pouco informativo e informativo. A presença da heterogeneidade de variâncias causa problemas para a seleção dos melhores indivíduos, principalmente se a heterogeneidade estiver...
Tipo: Simulação de dados
Palavras-chave: 5.04.02.00-5 heterogeneidade de variâncias; Componentes de variância; Simulação; Informação a priori Genética e Melhoramento dos Animais Domésticos heterogeneity of variance; Variance components; Simulation; Priori information.
Ano: 2010
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/7862

Development of a functional approach in a grassland vegetation - DOI: 10.4025/actascianimsci.v30i2.4679
Provedor de dados: 2
Autores: Sosinski Junior, Enio Egon; UFRGS; Carrère, Pascal; Institut National de la Recherche Agronomique; Louault, Frédérique; Institut National de la Recherche Agronomique; Soussana, Jean-François; Institut National de la Recherche Agronomique.
To improve our understanding of grassland dynamics under different levels of utilization, a functional description of the vegetation was introduced in a deterministic model. The selected traits and their parameterization were based on the results of a long-term experiment in which temperate grasslands were managed for 12 years with three levels of herbage use: high, medium and low. The integration of functional attributes of the community species within the model’s parameters can be seen as a new step in the study of the grassland ecosystem. With this tool, it is possible to decrease the number of interconnections in the system and consequently decrease the complexity. In this work a, functional definition of three different grassland communities was...
Palavras-chave: 5.04.04.00-8    Pastagem e Forragicultura extensification; Grassland vegetation; Models; Simulation; Functional attributes; Vegetation communities.
Ano: 2008
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/4679

Evaluation of FEM modelling for stress propagation under pressure wheel of corn planter
Provedor de dados: 111
Autores: Khodaei, M.; Fattahi, S. H. Fattahi; Navid, H.
Seeds need a certain range of pressure in the soil bed to germinate and grow ideally. Usually pressure from machinery wheels applies more pressure and prevents seed ideal germination. A finite element model (FEM) was developed to investigate stress propagation in the soil. The pressure wheel of corn planter with 4 km/h speed was chosen to analyze the stress in a sandy-loamy soil. A real corn planter tire was modeled with its mechanical characteristics and imported into ABAQUS/Explicit environment. Frictional contact (based on Mohr-coulomb theory) was used for the soil-tire interaction. The soil was considered as an elastic-perfectly plastic material. Drucker-Prager model was used for soil behavior in plastic region. To evaluate the stress under pressure...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agricultural Machinery stress distribution; Soil; Tire; ABAQUS/Explicit; Simulation.
Ano: 2016
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3772

COMPUTATIONAL FLUID DYNAMICS AND PERFORMANCE EVALUATION OF A CHIMNEY SOLAR DRYER FOR CHILLI PEPPER
Provedor de dados: 111
Autores: Kumi, Francis.
The postharvest losses of agricultural produce in Ghana and other developing countries is high. Efforts to promote shelf-life extension of the fresh produce is centred around temperature and moisture management. Moisture control by drying is suited to a number of crops as it inhibits microbial decay and physiological processes of deterioration. However, there are often inefficient drying infrastructure in developing countries. Thus, the focus of this research was to structurally modify a chimney solar dryer originally designed by the Horticulture Innovation Laboratory of the University of California, Davis and include sea pebbles in the collector base to enhance its heating system and drying performance.  A computational fluid dynamics analysis using ANSYS...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chimney; Dryer; Computational fluid dynamics; Simulation; Moisture content.
Ano: 2022
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7005

Computational Modeling of Trombe Wall Solar Chick Brooding House for Optimal Poultry Production
Provedor de dados: 111
Autores: Ohagwu, Chukwuemeka Jude; Okonkwo, Ifeanyi Wilfred; Mbah, Godwin Christopher Ezike; Njoku, Howard Okezie.
Computational modeling, simulation and validation were carried out on Trombe wall solar chick brooder used for optimal poultry production. Predictive linear differential equations based on physical, mathematical principles and relationships governing thermo-physical properties of the components of the brooder were formulated, discretized and expressed in their finite different forms using SCILAB 5.5.2. T-test statistics was carried out on predicted and measured mean data: temperature of Trombe wall glaze (TG1), temperature of pebble glaze (TG2), temperature of the pebble bed bin (Tp), temperature of the brooding room (TBr), and temperature of the Trombe wall outer surface (Tw (outer surface))then separated using Levene test for equality. The model...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Computational modeling; Passive Trombe wall solar chick brooder; Simulation; Validation; Poultry production.
Ano: 2021
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/6833

Assessment of the CERES-Rice model for rice production in Ibadan, Nigeria
Provedor de dados: 111
Autores: Christopher Oluwakunmi Akinbile; FUTA.
CERES-Rice model was used to simulate growth and yield of a new rice variety in Nigeria with the attention on rates of water application, one major factor that retards crop’s grain yield. The rates were full irrigation (100%ET), medium (75% ET), average (50% ET) and low (25% ET) irrigation intervals. The NEw RIce for AfriCA (acronym for NERICA) 2 variety was grown at the International Institute for Tropical Agriculture (IITA), Ibadan, Nigeria. Experimental agronomic values of parameters such as plant height, root depth, canopy shading, Leaf area index (LAI), biomass and grain yield in relation to water use were obtained and compared with simulated modelled values from CERES and the results were subjected to statistical analysis. The model predicted...
Palavras-chave: Agricultural Engineering; Soil and Water Conservation Engineering Rice; Model; Water; Simulation; Production; Food security.
Ano: 2013
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2405

Steady-state simulation of the seawater greenhouse condenser
Provedor de dados: 111
Autores: Al-Ismaili, Abdulraim M.; Weatherhead, Edward K.
This paper presents an integrated steady-state model simulating the condenser of the seawater greenhouse in Oman. The developed model is capable of predicting the outlet air temperature and humidity, the outlet seawater temperature and the condensation rate. Validation experiments showed a good conformity between the predicted and measured values within the calibration ranges at high and low air flowrates. The mean predictive error (PE) for the predicted condensation rate was 15.25 and 22.67 ml/min at high and low flowrates, respectively and the index of agreement (IA) was 0.96 and 0.98, respectively. The model also accurately predicted the outlet humidity ratio with PE values of -0.00006 and -0.00018 kg/kg for high and low air flowrates, respectively and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agricultural engineering  greenhouses Humidification-dehumification; Seawater greenhouse; Condenser; Simulation.
Ano: 2018
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4644

Spatial Analysis For Simulation The Changing Of Inland Water Depth: A Case Study In The Mekong Delta, Vietnam
Provedor de dados: 111
Autores: Minh, Vo Quang; Quang, Truong Chi; Diep, Nguyen Thi Hong; Diem, Phan Kieu.
Vietnam is one of the most affected countries by the global sea-level rise, in which the Mekong Delta is the most heavily impacted area due to the low-lying position. By combining spatial geostatistics and Kriging interpolation techniques to delineate the elevation maps with the assumption of inland water level increasing under sea-level rise by interpolating 967 elevations geo-rectified data from the topographic map at 1/250,000 scale. The inland water level maps with different inundated inland water level scenarios from 0.2 to 2.8m were delineated.The result showed that the exponential model selected for interpolation of elevation data, distance A0 = 585.900 meters; coefficiency R2 = 0,985; and Residue Sum of Square RSS = 0,0011; which were suitable and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Elevation; Flooding; Spatial interpolation.
Ano: 2022
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7477

AQUACULTURAL SYSTEM MANAGEMENT TOOL II: ANALYTICAL AND MANAGERIAL CAPABILITY
Provedor de dados: 111
Autores: Anyadike, Chinenye Chukwuemeka; Mbajiorgu, Constantine Crowner; Ajah, Genesis Nnaemeka.
One of the major objectives for developing ecosystem models is their application as tools of analysis for complex systems which otherwise would be difficult to analyze using conventional tools such as field experimentation and inventory monitoring. In view of this, the AQUASMAT model, which was developed based on existing ecosystem models theories and coded using the C-sharp language, was used to conduct a modeling study on a static concrete fish tank, to demonstrate its managerial and analytical capabilities. The input variables for model execution were site specific parameters, fish/feed parameters, water quality parameters and management options from selected fish farm in Nigeria. The model simulation was for concrete tanks with surface area of 1 m2 and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil; Water Resources and Aquacultural Engineering AQUASMAT; Simulation; Analytical; Managerial; Capability; Water quality; Inter-relationships.
Ano: 2017
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4308

Feed forward neural network and its reverse mapping aspects for the simulation of ginger drying kinetics
Provedor de dados: 111
Autores: Choudhary, Arun Kumar; Chakraborty, Sourav; Kumari, Sonam; Hazarika, Manuj K.
In the present study, simulation and modeling features of hot air based ginger drying kinetics were investigated by applying artificial neural system (ANN) and its reverse mapping aspects. Mapping of moisture ratio (MR) of the drying process as a function of temperature of drying (TD), slice thickness (ST) and drying time (DT) was accomplished based on the ANN architecture. A tale strategy of reverse neural system was built up to anticipate the drying process of ginger slices under given TD and ST for desired moisture content. Further, proportional odd displaying (POM) approach was applied for the tangible assessment of the dried samples. The ANN architecture, 3-5-1 was chosen as the best for modeling drying behavior of the ginger slices. Simulation of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ginger drying; ANN; Reverse ANN; Proportional odd modeling; Simulation.
Ano: 2022
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7373

Effect of Site Specific Weather Conditions on the Energy Consumption of a High Temperature Continuous Flow Corn Dryer
Provedor de dados: 111
Autores: de la Torre, Diego Antonio.
The estimation of drying energy consumption is important for grain elevators and the grain processing industry in order to compute the drying cost and also for properly planning the energy supply during the drying season. It is also important for making energy policies related to agriculture. Locations with different weather should have different drying performances but this effect was not sufficiently studied in previous research. The main goal of this study was to determine the energy requirement for drying yellow dent corn with a continuous flow high temperature dryer for ten locations in Argentina with different weather conditions. The study was carried out using historical weather data of ten locations scattered through the corn producing region of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Grain postharvest; Grain drying grain drying; Simulation; Energy balance; Energy losses; Ambient temperature.
Ano: 2014
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2962

Simulation of tensile tests of hemp fibre using discrete element method
Provedor de dados: 111
Autores: Chen, Ying; Sadek, Mohammad A.; Guzman, Leno; Lague, Claude; Landry, Hubert.
Abstract: Tensile strength is an important property of hemp fibre, because it determines the mechanical strength of fibre-based products such as biocomposites.  Commercial discrete element software, Particle Flow Code in Three Dimensions (PFC3D), was used to develop a numerical model which simulates tensile tests of hemp fibre.  The model can predict the tensile properties (such as strength and elongation) of a hemp fibre. In the model, a virtual hemp fibre was defined as a string of spherical balls, held together by cylindrical bonds implemented in PFC3D.  To calibrate the model, tensile data was collected for both unretted and retted hemp fibres using a commercial Instron testing system.  The average fibre diameter was 0.34 mm for the unretted fibre and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bioprocessing; Machinery Hemp; Fibre; PFC3D; Tensile; Strength; Elongation; Simulation.
Ano: 2014
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2455

Validation of simulated dynamic behavior of sprayer boom in SOLIDWORKS through actual field experiments
Provedor de dados: 111
Autores: Pashaee, Payam.
Dynamic behavior of agricultural implements has always been a challenging topic for researchers. In precision farming, precise control of the agricultural implements is a very important task. To study the dynamics of agricultural implements, Researchers conduct field experiments as well as laboratory tests. These methods are very costly and the measurements are usually associated with some errors. Providing well-controlled experimental conditions in practice is very difficult, if not impossible. In this article, the capability of the SolidWorks in simulation and predicting the dynamic behavior of a conventional sprayer boom is discussed. To validate the results, field tests were conducted using a conventional sprayer boom. The results showed that there was...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Boom sprayers; SolidWorks; Dynamic behavior.
Ano: 2023
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/5509

Integrated approach for prediction of centrifugal fertilizer spread patterns
Provedor de dados: 111
Autores: Marinello, Francesco; Pezzuolo, Andrea; Gasparini, Franco; Sartori, Luigi.
The present paper proposes a numerical approach for prediction of behavior of those fertilizers spreaders based on centrifugal disc functioning. In particular results from finite element multi-body simulations provided by commercial software are used in order to define boundary conditions of field tests carried out concurrently. Results are then integrated into a mathematical model to rapidly generate distribution charts and distribution diagrams.Such integrated approach can be implemented to effectively calibrate a theoretical model which provide simulations on different machine settings conditions: as a final point simulations allow fast testing of different distribution conditions, helping definition of those which minimize the variability of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Fertilizer; Spreader; Distribution.
Ano: 2017
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4177

Simulation of negative pressure behavior using different shapes and positions of pressure inlet and seed hole diameters using ANSYS-CFX to optimize the structure of a pneumatic metering device designed for wheat
Provedor de dados: 111
Autores: Satti, Yasir Hassan; Liao, Qingxi.
Abstract: the pneumatic precision metering device for wheat was innovated, designed and tested under laboratory conditions. Very good results were then obtained according to the precision seeding criteria based on quality of feed index (QFI), miss index (MIS) and multiple index (MULI). To optimize the structure of the design for gas stability before manufacturing, ANSYS-CFX was involved. Gas behavior was simulated under different shapes and positions for pressure inlet along with different seed hole diameters. According to the structure determined in ANSYS-CFX, the seed hole of 1.8 mm and cylindrical shape of pressure inlet was found to be the best among others, accordingly the deice was then manufactured and tested under laboratory and field conditions....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Precision metering device; Negative pressure behavior.
Ano: 2014
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3048

Genetic Population Structure and Allele Surfing During Range Expansion in Dynamic Habitats
Provedor de dados: 42
Autores: BRAGA,ROSANA T.; RODRIGUES,JOÃO F.M.; DINIZ-FILHO,JOSÉ A.F.; RANGEL,THIAGO F.
Abstract: Expanding populations may loss genetic diversity because sequential founder events throughout a wave of demographic expansion may cause “allele surfing”, as the alleles of founder individuals may propagate rapidly through space. The spatial components of allele surfing have been studied by geneticists, but have never been investigate on dynamic and shifting habitats. Here we used an individual-based-model (IBM) to study how interactions between different habitat restoration scenarios and biological characteristics (dispersal capacity) affect the spatial patterns of the genetic structure of a population during demographic expansion. We found that both habitat dynamics and dispersal capacity, as well as their interaction, were the drivers of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Allele surfing; Dispersal; Habitat suitability; Individual-based-model; Simulation.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000300607

Short and long period optimization of drug doses in the treatment of AIDS
Provedor de dados: 42
Autores: CAETANO,MARCO A. L.; YONEYAMA,TAKASHI.
Numerical optimization techniques are useful in solving problems of computing the best inputs for systems described by mathematical models and when the objectives can be stated in a quantitative form. This work concerns the problem of optimizing the drug doses in the treatment of AIDS in terms of achieving a balance between the therapeutic response and the side effects. A mathematical model describing the dynamics of HIV viruses and CD4 cells is used to compute the short term optimal drug doses in the treatments of patients with AIDS by a direct method of optimization using a cost function of Bolza type. The model parameters were fitted to actual published clinical data. In order to simplify the numerical procedures, the control law is expressed as a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Modeling; Simulation; Drugs; Treatment; AIDS.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000300002

Corn performance with late sowing in Planalto Catarinense, Brazil, simulated with CERES-maize model
Provedor de dados: 52
Autores: Cardoso,Célio Orli; Soccol,Olívio José.
This work had the objective to investigate the delay effects in the sowing date on corn establishment, cycle duration and yield through the computer simulations using CERES-Maize model, in order to help agrarian producers from the Mountainous Area of Santa Catarina, Brazil to take better decisions on it. The computer simulations showed that: 1)the risks on corn establishment increased due to the delay of sowing during the studied years; 2) in some years, its cycles were drastically affected for the lower temperatures; 3) the cycle durations were longer when confronted with the low temperatures; 4) corn income decreased when the cycles were confronted with the low temperatures, water deficiency and low solar radiation; 5) potential incomes averaged 4944 kg...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Simulation; Mathematical Model; Sowing date.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000400002

Stochastic modeling for a better approach of the in vitro observed growth of colon adenocarcinoma cells
Provedor de dados: 52
Autores: Ruiz-Gómez,Miguel J.; Ruiz-Gómez,Antonio; Martínez Morillo,Manuel.
The definition of a stochastic model that reflects the cell growth and the use of computer software could be very useful in modelling the cell behaviour due to the possibility to introduce alterations in biology parameters to obtain different growth patterns without the use of laboratory material. Human colon adenocarcinoma cells were cultured and a growth curve was made by daily count of the cell number. Pielou modelling was applied for stochastic simulation of deterministic growth, making stochastic the cell division, the death rates and the transition time between division and death, by using different probabilities. A greater growth was produced when the cell division rate increased, considering the density dependence constant. In contrast, a lower...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Colon carcinoma; Cell growth; Stochastic; Deterministic; Simulation.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000300006

Modeling, simulation, and analysis of a reactor system for the generation of white liquor of a pulp and paper industry
Provedor de dados: 52
Autores: Andreola,Ricardo; Jorge,Regina Maria Matos; Santos,Onélia Aparecida Andreo dos; Jorge,Luiz Mario de Matos.
An industrial system for the production of white liquor of a pulp and paper industry, Klabin Paraná Papéis, formed by ten reactors was modeled, simulated, and analyzed. The developed model considered possible water losses by the evaporation and reaction, in addition to variations in the volumetric flow of lime mud across the reactors due to the composition variations. The model predictions agreed well with the process measurements at the plant and the results showed that the slaking reaction was nearly complete at the third causticizing reactor, while causticizing ends by the seventh reactor. Water loss due to slaking reaction and evaporation occurred more pronouncedly in the slaker reactor than in the final causticizing reactors; nevertheless, the lime...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Slaker reactor; Causticizing reactor; White liquor; Mathematical modeling; Simulation.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000100024

Estimation of population profiles of two strains of the fly Megaselia scalaris (Diptera: Phoridae) by bootstrap simulation
Provedor de dados: 57
Autores: MANZATO,A. J.; TADEI,W. J.; CORDEIRO,J. A.
Based on experimental population profiles of strains of the fly Megaselia scalaris (Phoridae), the minimal number of sample profiles was determined that should be repeated by bootstrap simulation process in order to obtain a confident estimation of the mean population profile and present estimations of the standard error as a precise measure of the simulations made. The original data are from experimental populations founded with SR and R4 strains, with three replicates, which were kept for 33 weeks by serial transfer technique in a constant temperature room (25 ± 1.0°C). The variable used was population size and the model adopted for each profile was a stationary stochastic process. By these simulations, the three experimental population profiles were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bootstrap; Megaselia; Populations; Simulation; Population size.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-71082000000300006

Can course format influence the performance of students in an advanced cardiac life support (ACLS) program?
Provedor de dados: 56
Autores: Garrido,F.D.; Romano,M.M.D.; Schmidt,A.; Pazin-Filho,A.
Advanced cardiac life support (ACLS) is a problem-based course that employs simulation techniques to teach the standard management techniques of cardiovascular emergencies. Its structure is periodically revised according to new versions of the American Heart Association guidelines. Since it was introduced in Brazil in 1996, the ACLS has been through two conceptual and structural changes. Detailed documented reports on the effect of these changes on student performance are limited. The objective of the present study was to evaluate the effect of conceptual and structural changes of the course on student ACLS performance at a Brazilian training center. This was a retrospective study of 3266 students divided into two groups according to the teaching model:...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Advanced cardiac life support; Cardiac arrest; Simulation.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000100004

Characterization of genetic coefficients of durum wheat (Triticum turgidumL. ssp. durum)'Llareta-INIA' and 'Corcolén-INIA'
Provedor de dados: 117
Autores: Garrido,Marco; Román,Luis; Silva,Paola; Castellaro,Giorgio; García de Cortázar,Víctor; Acevedo,Edmundo.
The genetic coefficients, representative of a crop, are necessary to use growth models; in many cases the range of the species is known, but there are no specific values for varieties. Durum wheat (Triticum turgidumL. ssp. durum)'Llareta-INIA' and 'Corcolén-INIA' were sown under irrigation in the experiment station Antumapu of the Universidad de Chile on 29 June 2007, 19 May 2009, and 15 June 2010 in order to determinate four genetic coefficients: developmental thermal time, phyllochron (PHLN), extinction coefficient (k), and radiation use efficiency (RUE), and to evaluate the performance of these coefficients. Thermal times to anthesis and from anthesis to physiological maturity were 652 and 541 °C d, respectively. Two PHLN values were found, 46.6 °C d...
Tipo: Journal article
Palavras-chave: Simulation; Thermal time; Radiation use efficiency; Extinction coefficient.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392013000200002

ECONOMICAL AND FINANCIAL ANALYSIS OF AVIARIES FOR THE INTEGRATION OF BROILERS UNDER CONDITIONS OF RISK
Provedor de dados: 64
Autores: Simões,Danilo; Ribeiro,João Paulo; Gouveia,Pedro Rodrigo; Santos,Josiane Corrêa dos.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agribusiness; Production cost; Monte Carlo method; Simulation; Net present value.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542015000300240

Alternative to Tukey test
Provedor de dados: 64
Autores: Batista,Ben Dêivide de Oliveira; Ferreira,Daniel Furtado.
ABSTRACT In order to search for an ideal test for multiple comparison procedures, this study aimed to develop two tests, similar to the Tukey and SNK tests, based on the distribution of the externally studentized amplitude. The test names are Tukey Midrange (TM) and SNK Midrange (SNKM). The tests were evaluated based on the experimentwise error rate and power, using Monte Carlo simulation. The results showed that the TM test could be an alternative to the Tukey test, since it presented superior performances in some simulated scenarios. On the other hand, the SNKM test performed less than the SNK test.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Type I error rate; Simulation; Range; Midrange; MidrangeMCP package.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542020000100240