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Registros recuperados: 34 | |
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Zavala-Pineda,M. Jesica; Salas-González,J. María; Leos-Rodríguez,J. Antonio; Sagarnaga-Villegas,L. Myriam. |
En este estudio se destaca la relevancia de los estudios prospectivos en el diseño de una política agropecuaria diferenciada para México y en la identificación de los efectos potenciales de políticas sectoriales diferenciadas. Por tanto, el objetivo del estudio fue analizar la viabilidad económica de unidades representativas de producción (URP) porcícola en los estados de Jalisco, Sonora y Guanajuato. La técnica de paneles se usó para modelar 15 URP con la participación de 137 productores, con granjas similares en tecnología, escala, sistema de producción, ubicación geográfica y mercado de destino del producto. Mediante consensos se identificó la información técnica y financiera relevante para construir el Año Base 2008. Con esta información y empleando el... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Análisis prospectivo; Monte Carlo; Paneles; Simulación; Transferencias gubernamentales. |
Ano: 2012 |
URL: http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1405-31952012000700008 |
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Miyajima, Ricardo Hideaki; Tonin, Rodrigo Petrongari; Fenner, Paulo Torres; Simões, Danilo. |
Os custos da colheita florestal, de forma abrangente, podem ser definidos como a quantificação econômica dos fatores produtivos, determinados em sua maioria pelo modal utilizado. Todavia, um elemento presente no conhecimento dos custos desses modais é a incerteza nas estimativas, devido ao conjunto de fatores envolvidos ou da insuficiência de informações. À vista disso, objetivou-se neste estudo construir um modelo estocástico, a partir da produtividade operacional de um trator florestal skidder empregado na extração de Eucalyptus sp., para quantificar os riscos técnico-econômicos por meio da simulação de Monte Carlo. A análise técnico-econômica teve como premissa o estudo de tempos e métodos, seguida da estimativa do custo horário do trator florestal... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Colheita florestal; Custos de extração; Monte Carlo; Silvicultura; Tempos e métodos. |
Ano: 2017 |
URL: http://revistas.ufpr.br/biofix/article/view/56339 |
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Xavier,Ana Carolina Freitas; Blain,Gabriel Constantino; Morais,Marcos Vinicius Bueno de; Sobierajski,Graciela da Rocha. |
ABSTRACT The selection of an appropriate nonstationary Generalized Extreme Value (GEV) distribution is frequently based on methods, such as Akaike information criterion (AIC), second-order Akaike information criterion (AICc), Bayesian information criterion (BIC) and likelihood ratio test (LRT). Since these methods compare all GEV-models considered within a selection process, the hypothesis that the number of candidate GEV-models considered in such process affects its own outcomehas been proposed. Thus, this study evaluated the performance of these four selection criteria as function of sample sizes, GEV-shape parameters and different numbers candidate GEV-models. Synthetic series generated from Monte Carlo experiments and annual maximum daily rainfall... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Monte Carlo; GEV; MIROC5; Downscaling. |
Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052019000400606 |
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Silva,Roberta Bessa Veloso; Ferreira,Daniel Furtado. |
Conduziu-se este trabalho com o objetivo de avaliar os riscos de se tomar decisões erradas (erro tipo I e erro tipo II), com o aumento da diferença entre as variâncias populacionais, por meio de simulação computacional, utilizando-se o teste t de Student com o número de graus de liberdade sendo aproximado pelas alternativas de Satterthwaite (1946), valor mínimo υ = min (n1 - 1, n2 - 1) e pelo método de bootstrap. Duas populações foram geradas, e a variância da população 1 foi igual a um (σ21), e a da população 2 foi especificada em função da razão σ22/σ21, a qual assume os valores 1, 2, 8 e 16. Usando essas abordagens diferentes para o teste t, avaliaram-se as taxas de erro tipo I e tipo II. Todos os critérios controlaram adequadamente a taxa de erro tipo... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Erros tipo I e tipo II; Monte Carlo; Bootstrap. |
Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542003000100023 |
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Ferreira,Daniel Furtado. |
Sisvar is a statistical analysis system with a large usage by the scientific community to produce statistical analyses and to produce scientific results and conclusions. The large use of the statistical procedures of Sisvar by the scientific community is due to it being accurate, precise, simple and robust. With many options of analysis, Sisvar has a not so largely used analysis that is the multiple comparison procedures using bootstrap approaches. This paper aims to review this subject and to show some advantages of using Sisvar to perform such analysis to compare treatments means. Tests like Dunnett, Tukey, Student-Newman-Keuls and Scott-Knott are performed alternatively by bootstrap methods and show greater power and better controls of experimentwise... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Monte Carlo; Type I error; Power. |
Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542014000200001 |
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Heymans, Johanna Jacomina; Coll, Marta; Link, Jason S.; Mackinson, Steven; Steenbeek, Jeroen; Walters, Carl; Christensen, Villy. |
Ecopath with Ecosim (EwE) models are easier to construct and use compared to most other ecosystem modelling techniques and are therefore more widely used by more scientists and managers. This, however, creates a problem with quality assurance; to address this we provide an overview of best practices for creating Ecopath, models. We describe the diagnostics that can be used to check for thermodynamic and ecological principles, and highlight principles that should be used for balancing a model. We then highlight the pitfalls when comparing Ecopath models using Ecological Network Analysis indices. For dynamic simulations in Ecosim we show the state of the art in calibrating the model by fitting it to time series using a formal fitting procedure and... |
Tipo: Text |
Palavras-chave: Ecopath with Ecosim; Ecological network analysis; Ecosystem modelling; Ecosystem-based management; Monte Carlo; Time series fitting. |
Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00626/73763/74237.pdf |
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Huang, Ju-Chin; Smith, V. Kerry. |
This paper argues that the widespread belief that discrete contingent valuation (CV) questions yield substantially larger estimates of the mean (and the median) willingness to pay (WTP) for nonmarket environmental resources in comparison to estimates from open-ended CV questions is unfounded. A set of Monte Carlo experiments estimate the factors influencing the performance of WTP estimates based on discrete response models. Most of the error in the WTP estimates arises from the specification errors that are common in most of the empirical models used in the literature. These experiments suggest models based on choices where WTP is dominated by non use (or passive use) values are likely to have smaller errors than where large use values influence these... |
Tipo: Working or Discussion Paper |
Palavras-chave: Discrete response contingent valuation; Monte Carlo; Non-market valuation; Financial Economics; C93; D12; Q2. |
Ano: 1997 |
URL: http://purl.umn.edu/10546 |
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Bryant, Henry L.; Bessler, David A.. |
We describe a means of rejecting a null hypothesis concerning observed, but not deliberately manipulated, variables of the form H0: A -/-> B in favor of an alternative hypothesis HA: A --> B, even given the possibility of causally related unobserved variables. Rejection of such an H0 relies on the availability of two observed and appropriately related instrumental variables. While the researcher will have limited control over the confidence level in this test, simulation results suggest that type I errors occur with a probability of less than 0.15 (often substantially less) across a wide range of circumstances. The power of the test is limited if there are but few observations available and the strength of correspondence among the variables is weak.... |
Tipo: Conference Paper or Presentation |
Palavras-chave: Causality; Monte Carlo; Observational data; Hypothesis testing; Research Methods/ Statistical Methods. |
Ano: 2011 |
URL: http://purl.umn.edu/103238 |
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Marsh, Thomas L.. |
Wheat for food use is conceptualised as an input into flour production and demand is derived from an industry profit function to quantify price responsiveness and economic substitutability across wheat classes. Price and substitution elasticities are estimated for hard red winter, hard red spring, soft red wheat, soft white winter and durum wheat. In general, hard red winter and spring wheat varieties are much more responsive to their own price than are soft wheat varieties and durum wheat. Substitution elasticities indicate that hard red winter and hard red spring wheat are economic substitutes for milling purposes. |
Tipo: Article |
Palavras-chave: Elasticities; Like product; Monte Carlo; Wheat by class; Crop Production/Industries; Food Consumption/Nutrition/Food Safety. |
Ano: 2005 |
URL: http://purl.umn.edu/118503 |
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Tumusiime, Emmanuel; Brorsen, B. Wade; Mosali, Jagadeesh; Johnson, Jim; Locke, James; Biermacher, Jon T.. |
The parameters of yield response functions can vary by year. Past studies usually assume yield functions are nstochastic ‘‘limited’’ stochastic. In this study, we estimate rye– ryegrass yield functions in which all parameters are random. The three functional forms considered are the linear response plateau, the quadratic, and the Spillman-Mitscherlich. Nonstochastic yield models are rejected in favor of stochastic parameter models. Quadratic functional forms fit the data poorly. Optimal nitrogen application recommendations are calculated for the linear response plateau and Spillman-Mitscherlich. The stochastic models lead to smaller recommended levels of nitrogen, but the economic benefits of using fully stochastic crop yield functions are small because... |
Tipo: Journal Article |
Palavras-chave: Cereal rye–ryegrass; Monte Carlo; Nitrogen; Random parameters; Stochastic plateau; Production Economics; Q10; C12; D24. |
Ano: 2011 |
URL: http://purl.umn.edu/117949 |
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Batz, Michael B.; Albers, Heidi J.; Avalos-Sartorio, Beatriz; Blackman, Allen. |
Shade-grown coffee provides a livelihood to many farmers, protects biodiversity, and creates environmental services. Many shade-coffee farmers have abandoned production in recent years, however, in response to declines in international coffee prices. This paper builds a farmer decision model under price uncertainty and uses simulation analysis of that model to examine the likely impact of various policies on abandonment of shade-coffee plantations. Using information from coastal Oaxaca, Mexico, this paper examines the role of various constraints in abandonment decisions, reveals the importance of the timing of policies, and characterizes the current situation in the study region. |
Tipo: Working or Discussion Paper |
Palavras-chave: Coffee farming; Decision analysis; Numerical modeling; Monte Carlo; Price variability; Crop Production/Industries; O13; Q17; Q12; Q23; Q24. |
Ano: 2005 |
URL: http://purl.umn.edu/10511 |
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Kaiser, Johannes. |
This article concerns the nonparametric Fisher–Pitman tests for paired replicates and independent samples. After outlining the theory of exact tests, I derive Monte Carlo simulations for both of them. Simulations can be useful if one deals with many observations because of the complexity of the algorithms in regard to sample sizes. The tests are designed to be a more powerful alternative to the Wilcoxon signed-rank test and the Wilcoxon–Mann–Whitney rank-sum test if the observations are given on at least an interval scale. The results gained by Monte Carlo versions of the tests are accurate enough in comparison to the exact versions. Finally, I give examples for using both supplemented tests. |
Tipo: Article |
Palavras-chave: Permtest1; Permtest2; Nonparametric tests; Monte Carlo; Permutation tests; Research Methods/ Statistical Methods. |
Ano: 2007 |
URL: http://purl.umn.edu/119284 |
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Registros recuperados: 34 | |
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