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Registros recuperados: 25
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A Dynamic Optimisation Model of Weed Control AgEcon
Cacho, Oscar J.; Jones, Randall E..
It is argued in this paper that static approaches to weed management, where the benefits and costs are only considered within a single season, are inappropriate for assessing the economic benefits of weed control technologies. There are carryover effects from weed management as weeds that escape control in one season may reproduce and replenish weed populations in following seasons. Consequently, it is appropriate to view weed control in the context of a resource management problem where the goal is to determine the optimal inter-temporal level of weed control that maximises economic benefits over some pre-determined period of time. A dynamic optimisation model for weed control is presented. Using the tools of comparative static analysis and Pontryagin's...
Tipo: Working or Discussion Paper Palavras-chave: Weed control; Resource economics; Optimal control; Dynamic programming; Wild oats; Farm Management.
Ano: 2000 URL: http://purl.umn.edu/12902
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A Practical Algorithm for Multiple-Phase Control Systems in Agricultural and Natural Resource Economics AgEcon
Doole, Graeme J..
Many important problems in agricultural and natural resource economics concern an intertemporal choice between alternate dynamic systems. This significance has motivated a theoretical literature generalizing the necessary conditions of Optimal Control Theory to multiple-phase problems. However, gaining detailed insight into their practical management is difficult because general numerical solution methods are not available. This paper resolves this deficiency through the development of a flexible and efficient computational algorithm based on a set of necessary conditions derived for finite-time, multiple-phase systems. Its effectiveness is demonstrated in an application to a nontrivial crop rotation problem.
Tipo: Journal Article Palavras-chave: Crop management; Multiple-phase systems; Optimal control; Crop Production/Industries; Resource /Energy Economics and Policy.
Ano: 2009 URL: http://purl.umn.edu/50082
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An Optimization Model for the Banana Northern Prawn Fishery AgEcon
Valle de Souza, Simone; Gondro, Cedric; Cacho, Oscar J..
This study presents an optimal control model of the Banana Northern Prawn Fishery, one of the most important fisheries in Australia. The life cycle of this species involves migration between the sea, where the catch takes place, and the estuary, where post-larvae and juveniles develop. The model combines a stage-matrix population dynamics model and an economic model of sustainable catch. The controls involve the amount of effort allowed and the length of the fishing season. Life stages are defined in terms of prawn size, allowing catch revenue to be adjusted to the expected proportion of specific sized classes caught in a particular month of the year, hence providing a more realistic projection of profits when price is influenced by size. The model is...
Tipo: Conference Paper or Presentation Palavras-chave: Fisheries management; Australia; Optimal control; Profit maximisation; Banana prawns.; Resource /Energy Economics and Policy.
Ano: 2010 URL: http://purl.umn.edu/59173
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Analyzing the Economic Impact of Climate Change on Global Timber Markets AgEcon
Sohngen, Brent; Sedjo, Roger A.; Mendelsohn, Robert; Lyon, Kenneth S..
In this paper, we show how ecological and economic models can be linked to determine the economic impact of climate change on global timber markets. We begin by discussing some of the important issues relevant to global impact analyses such as this. We then outline our general modeling framework and discuss the particular models that will be used. Finally, we discuss some of the important issues involved with linking the two types of models.
Tipo: Working or Discussion Paper Palavras-chave: Climate change; Economic model; Timber; Timber market; Dynamic; Optimal control; Environmental Economics and Policy; Q10; Q23; Q24.
Ano: 1996 URL: http://purl.umn.edu/10462
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Approximating optimal numerical solutions to bio-economic systems: How useful is simulation-optimization? AgEcon
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
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COMMODITY R&D AND PROMOTION AgEcon
Richards, Timothy J.; Padilla, Luis.
Considerable evidence exists of high returns to public and private investment in commodity research and development programs. This study investigates the potential returns to product research, development, and marketing in a dynamic commodity-market model. Theoretical hypotheses derived from the solution to this model are tested in an empirical example of Washington apples. Estimation results show that, despite significant spillovers to research and promotion expenditure in this industry, there is nonetheless considerable latitude to increase annual sales.
Tipo: Journal Article Palavras-chave: Advertising; Commodity; Innovation; Optimal control; Poisson model; Research and development; Marketing; Research and Development/Tech Change/Emerging Technologies; L15; M37; Q13; Q16.
Ano: 2002 URL: http://purl.umn.edu/15083
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Cooperation, Spatial-Dynamic Externalities, and Invasive Species Management AgEcon
Epanchin-Niell, Rebecca S.; Wilen, James E..
Most terrestrial biological invasions occur in landscapes comprising numerous, independently managed properties. Thus, control of invasion spread generally depends on the choices of many managers, each deciding the extent to control invasions on their property. Here we develop a spatially-explicit, integrated model of invasion spread and human behavior to examine how people’s control choices under laissez-faire affect patterns of invasion spread and the total costs and damages imposed by an invader. We evaluate how characteristics of the bioeconomic and social system, including the extent of cooperation among managers, affect the divergence between socially optimal and private control efforts. We find that system-wide invasion externalities generally...
Tipo: Conference Paper or Presentation Palavras-chave: Biological invasions; Cross-boundary; Coordination; Spatial-dynamic processes; Spatial spread; Eradication; Containment; Negotiation; Optimal control; Cooperative management; Environmental Economics and Policy; Land Economics/Use; Public Economics; Resource /Energy Economics and Policy; Q; Q1; Q2; Q5; H4.
Ano: 2010 URL: http://purl.umn.edu/61371
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Dynamic Programming and Learning Models for Management of a Nonnative Species AgEcon
Eiswerth, Mark E.; van Kooten, G. Cornelis; Lines, Jeff M.; Eagle, Alison J..
Nonnative invasive species result in sizeable economic damages and expensive control costs. Because dynamic optimization models break down if controls depend in complex ways on past controls, non-uniform or scale-dependent spatial attributes, etc., decision support systems that allow learning may be preferred. We compare three models of an invasive weed in California’s grazing lands: (1) a stochastic dynamic programming model, (2) a reinforcement-based, experience-weighted attraction (EWA) learning model, and (3) an EWA model that also includes stochastic forage growth and penalties for repeated application of environmentally harmful control techniques. Results indicate that EWA learning models may be appropriate for invasive species management.
Tipo: Working or Discussion Paper Palavras-chave: Invasive weed species; Optimal control; Adaptive management; Environmental Economics and Policy; C73; Q57.
Ano: 2005 URL: http://purl.umn.edu/37015
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Heterogeneity among agent types and second-best management for non-market ecological services AgEcon
Fenichel, Eli P..
Second-best management affects different agent types differently, and heterogeneity among agents may create instances when only second best management is feasible. Capital-theoretic bioeconomic modeling often has imposed representative agent assumptions that may not capture this heterogeneity. Interactions between agent heterogeneity and second-best management have received little attention. Such heterogeneity is particularly important when management actions do not directly affect extensive margin decisions. We employ a microparameter model in a dynamic bioeconomic model to incorporate agent heterogeneity and intensive and extensive margin decisions for a nonmarket good, recreational fishing. The model yields qualitatively different management...
Tipo: Conference Paper or Presentation Palavras-chave: Entry-exit; Microparameter; Bioeconomics; Recreational fishing; Landing limits; Optimal control; Resource /Energy Economics and Policy; Q20; Q22; Q26.
Ano: 2009 URL: http://purl.umn.edu/48995
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Induced-Innovation and Invasive Species Management AgEcon
Kim, C.S.; Schaible, Glenn D.; Lewandrowski, Jan.
Public policy for managing invasive species has largely focused on preventive measures prior to detection (stage 1) and on the use of chemical/mechanical or biological control measures after the establishment and dispersion of the invasive species (stage 2). Optimal management policy depends both on the initial stock of the invasive species and on the costs associated with conventional control measures. However, little attention has focused on how an induced technology such as Bt corn and Bt cotton is developed and adopted by farmers (stage 3), or how it affects the manageability of economic and ecological damages from an invasive species. This analysis evaluates the optimal allocation of management resources between preventive and control measures for...
Tipo: Conference Paper or Presentation Palavras-chave: Invasive species; Preventive measures; Control measures; Induced technology; Hazard function; Optimal control; Comparative dynamic analysis; Environmental Economics and Policy; Production Economics.
Ano: 2010 URL: http://purl.umn.edu/60985
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Managing European Corn Borer Resistance to Bt Corn with Dynamic Refuges AgEcon
Secchi, Silvia; Hurley, Terrance M.; Hellmich, Richard L..
Genetically engineered Bt (Bacillus thuringiensis) corn provides farmers with a new tool for controlling the European corn borer (ECB). The high efficacy and potential rapid adoption of Bt corn has raised concerns that the ECB will develop resistance to Bt. The Environmental Protection Agency has responded to these concerns by requiring farmers to plant refuge corn. Current refuge requirements are based on models that do not consider the value of dynamically varying refuge in response to increased scarcity and diminished control over time or the importance of backstop technologies currently being developed. The purpose of this paper is to evaluate dynamically optimal refuge requirements with the arrival of alternative backstop technologies and to compare...
Tipo: Working or Discussion Paper Palavras-chave: Bt corn; Optimal control; Pesticide resistance; Crop Production/Industries.
Ano: 2001 URL: http://purl.umn.edu/18626
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Market-Based Instruments for the Optimal Control of Invasive Insect Species: B. Tabaci in Arizona AgEcon
Richards, Timothy J.; Ellsworth, Peter; Tronstad, Russell; Naranjo, Steve.
Invasive insect species represent perhaps one of the most significant potential sources of economic risk to U.S. agricultural production. Private control of invasive insect species is likely to be insufficient due to negative externality and weaker-link public good problems. In this study, we compare a system of Pigouvian taxes with tradable permits for invasive species control. While the emissions control literature shows that taxes are preferred to permits under cost uncertainty, invasive-species control involves correlated cost and benefit uncertainty. Hence, we expect a quantity-based system to be preferred. Monte Carlo simulations of optimal steady-state outcomes confirm our expectations.
Tipo: Journal Article Palavras-chave: Externalities; Invasive species; Optimal control; Permits; Spatial-temporal model; Taxes; Crop Production/Industries; Resource /Energy Economics and Policy.
Ano: 2010 URL: http://purl.umn.edu/97852
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Market-Based Instruments for the Optimal Control of Invasive Insect Species: B. Tabaci in Arizona AgEcon
Richards, Timothy J.; Ellsworth, Peter; Tronstad, Russell; Naranjo, Steve.
Invasive insect species represent perhaps one of the most significant potential sources of economic risk to U.S. agricultural production. Private control of invasive insect species is likely to be insufficient due to negative externality and weaker-link public good problems. In this study, we compare a system of Pigouvian taxes with tradable permits for invasive species control. While the emissions control literature shows that taxes are preferred to permits under cost uncertainty, invasive species control involves correlated cost and benefit uncertainty, so we expect a quantity-based system to be preferred. Monte Carlo simulations of optimal steady-state outcomes confirm our expectations.
Tipo: Conference Paper or Presentation Palavras-chave: Externalities; Invasive species; Optimal control; Permits; Spatial-temporal model; Taxes.; Environmental Economics and Policy; Public Economics; Risk and Uncertainty; H23; L51; Q28; Q57..
Ano: 2010 URL: http://purl.umn.edu/61189
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Modelling Environmental Effects of Agriculture: The Case of Organic Rye and Grey Partridge AgEcon
Miettinen, Antti; Huhtala, Anni.
Our optimal control model identifies economic reasons as to why farmland bird populations have dramatically declined in modern agricultural landscapes. By integrating recreational wildlife values into farm level decision-making on arable crop choice and herbicide use, we derive those economic instruments needed for creating suitable conditions for game bird species on farmland. Based on the Finnish data available on the grey partridge (Perdix perdix), we illustrate how the optimal acreage subsidy for organically-grown areas, herbicide tax rates and the hunting licence fee could be estimated in monetary terms. Finally, we discuss the benefits and costs of cultivating organic cereals which will enhance preservation of the grey partridge.
Tipo: Conference Paper or Presentation Palavras-chave: Environmental benefits; Grey partridge; Herbicides; Optimal control; Rye; Environmental Economics and Policy; Q57; Q18; H41.
Ano: 2005 URL: http://purl.umn.edu/24462
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Multiregional Invasive Species Management: Theory and an Application to Florida's Exotic Plants AgEcon
Kim, C.S.; Lee, Donna J.; Schaible, Glenn D.; Vasavada, Utpal.
This research develops a multiregional optimal control model that incorporates regional allocation of a public budget for controlling invasive plants when regionally differential recreation demand functions and species control costs are present. Our equimarginal condition for optimal budget allocation equates the relative marginal economic benefits per dollar spent across regions. The model was applied to Florida Public Conservation Land regions, and results indicate that the magnitude of an annual management budget affects its distribution among species management regions, but the size of the intrinsic growth rate does not affect the pattern of budget allocation among regions.
Tipo: Journal Article Palavras-chave: Budget allocation; Equimarginal condition; Florida invasive species; Invasive plants; Optimal control; B41; C02; Q51; Q57.
Ano: 2007 URL: http://purl.umn.edu/37141
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Optimal control of bacterial growth for the maximization of metabolite production ArchiMer
Yegorov, Ivan; Mairet, Francis; De Jong, Hidde; Gouze, Jean-luc.
Microorganisms have evolved complex strategies for controlling the distribution of available resources over cellular functions. Biotechnology aims at interfering with these strategies, so as to optimize the production of metabolites and other compounds of interest, by (re)engineering the underlying regulatory networks of the cell. The resulting reallocation of resources can be described by simple so-called self-replicator models and the maximization of the synthesis of a product of interest formulated as a dynamic optimal control problem. Motivated by recent experimental work, we are specifically interested in the maximization of metabolite production in cases where growth can be switched off through an external control signal. We study various optimal...
Tipo: Text Palavras-chave: Optimal control; Nonlinear dynamical systems; Mathematical modelling; Bacterial growth; Biotechnology.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00486/59791/63028.pdf
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Optimal Control of Brucellosis in Bison in the Yellowstone National Park Area AgEcon
Xie, Fang; Horan, Richard D..
Brucellosis is a highly infectious bacterial disease that causes infected females to abort their calves. It has caused devastating losses to U.S. farmers over the last century. The only known focus of Brucellosis left in the nation is wildlife such as bison and elk in the Greater Yellowstone Area. Vaccination and test-and-slaughter have been applied to brucellosis management in bison, and there has been discussion that a combination of both could potentially eradicate the disease in the Yellowstone National Park. However, there is no study on how to allocate resources between the two actions. This paper investigates the optimal allocation of these two selective management options, in a bioeconomic framework, when there are both existence and recreational...
Tipo: Conference Paper or Presentation Palavras-chave: Bioeconomics; Brucellosis; Disease ecology; Epidemiology; Optimal control; Susceptible-infected-recovered (SIR) model; Resource /Energy Economics and Policy.
Ano: 2010 URL: http://purl.umn.edu/61334
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Optimal feedback strategies for bacterial growth with degradation, recycling, and effect of temperature ArchiMer
Yegorov, Ivan; Mairet, Francis; Gouze, Jean-luc.
Mechanisms of bacterial adaptation to environmental changes are of great interest for both fundamental biology and engineering applications. In this work, we consider a continuous-time dynamic problem of resource allocation between metabolic and gene expression machineries for a self-replicating prokaryotic cell population. In compliance with evolutionary principles, the criterion is to maximize the accumulated structural biomass. In the model, we include both the degradation of proteins into amino acids and the recycling of the latter (ie, using as precursors again). On the basis of the analytical investigation of our problem by Pontryagin's maximum principle, we develop a numerical method to approximate the switching curve of the optimal feedback control...
Tipo: Text Palavras-chave: Bacterial growth; Chattering regime; Effect of temperature; Feedback strategy; Optimal control; Pontryagin's maximum principle; Protein degradation; Recycling; Resource allocation; Singular regime; Switching curve.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00434/54592/56057.pdf
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Permanence of Carbon Sequestered in Forests under Uncertainty AgEcon
Kim, C.S.; Lewandrowski, Jan; Sands, Ronald D.; Johansson, Robert C..
In this paper we examine the issue of permanence in the context of sequestering carbon through afforestation. We develop a dynamic nested optimal control model of carbon sequestration associated with the decision to afforest a tract of land given there are uncertainties associated with fire and insect/disease hazards. Conceptually, these potential hazards are similar in that their occurrence at any time t is uncertain and landowners can take specific actions – although generally different actions - in any time period t to reduce the probability of sustaining losses related to them. The hazards differ, however, in that fire represents a large loss in carbon at a moment in time, while insect/disease infestations are more likely to be reflected in a period...
Tipo: Conference Paper or Presentation Palavras-chave: Carbon sequestration; Uncertainty; Optimal control; Hazard function; Forestry; Permanence; Environmental Economics and Policy; Land Economics/Use.
Ano: 2011 URL: http://purl.umn.edu/103565
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Prevention, Eradication, and Containment of Invasive Species: Illustrations from Hawaii AgEcon
Burnett, Kimberly M.; Kaiser, Brooks A.; Pitafi, Basharat A.K.; Roumasset, James A..
Invasive species change ecosystems and the economic services such ecosystems provide. Optimal policy will minimize the expected damages and costs of prevention and control. We seek to explain policy outcomes as a function of biological and economic factors, using the case of Hawaii to illustrate. First, we consider an existing invader, Miconia calvescens, a plant with the potential to reduce biodiversity, soil cover, and water availability. We then examine an imminent threat, the potential arrival of the Brown treesnake (Boiga irregularis). The arrival of the snake in Guam has led to native bird extirpations, power outages, and health costs.
Tipo: Journal Article Palavras-chave: Invasive species; Bioeconomics; Optimal control; Miconia calvescens; Boiga; Resource /Energy Economics and Policy.
Ano: 2006 URL: http://purl.umn.edu/10178
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