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Registros recuperados: 15
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A Stochastic Differential Equation for Modeling the “Classical” Probability Distributions AgEcon
Hertzler, Greg.
Stochastic differential equations are a flexible way to model continuous probability distributions. The most popular differential equations are for non-stationary Lognormal, non-stationary Normal and stationary Ornstein-Uhlenbeck distributions. The probability densities are known for these distributions and the assumptions behind the differential equations are well understood. Unfortunately, the assumptions do not fit most situations. In economics and finance, prices and quantities are usually stationary and positive. The Lognormal and Normal distributions are nonstationary and the Normal and Ornstein-Uhlenbeck distributions allow negative prices and quantities. This study derives a stochastic differential equation that includes most of the classical...
Tipo: Conference Paper or Presentation Palavras-chave: Research Methods/ Statistical Methods.
Ano: 2003 URL: http://purl.umn.edu/57891
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AN OPTIMAL CONTROL MODEL FOR INTEGRATED WEED MANAGEMENT UNDER HERBICIDE RESISTANCE AgEcon
Gorddard, Russell J.; Pannell, David J.; Hertzler, Greg.
The presence of weeds which have developed resistance to chemical herbicides is a problem of rapidly growing importance in Australian agriculture. We present an optimal control model of herbicide resistance development in ryegrass, the weed for which resistance is most commonly reported. The model is used to select the optimal combination of chemical and non-chemical control measures taking account of the trade off between short term profits and the long term level of herbicide resistance. Results indicate that given the threat of resistance there are benefits from integrating a combination of chemical and non-chemical control measures. The optimal strategy is found to include a declining herbicide dosage as resistance develops, with compensatory increases...
Tipo: Journal Article Palavras-chave: Research and Development/Tech Change/Emerging Technologies.
Ano: 1995 URL: http://purl.umn.edu/22858
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COORDINATING PRODUCTION AND DISPOSAL OF COMMODITY STOCKPILES WITH APPLICATION TO AUSTRALIA'S WOOL INDUSTRY AgEcon
Hertzler, Greg.
Following the dismantling of a price-support program, a central bureaucracy is left with a commodity stockpile to dispose. It happened with wheat and feed grains in the U.S. in 1986 and wool in Australia in 1991. It soon may happen in Europe with grains, manufactured dairy products and other commodities which have supported prices. Obvious policies include privatising the stockpile, disposing of the stockpile by a central bureaucracy and quarantining the stockpile from the market. Each policy imposes constraints on disposal based, perhaps, on judgments of political acceptability to producers and government. In this article, optimal rules for production and disposal are derived and solved and a new policy is proposed. Then the model is applied to the...
Tipo: Journal Article Palavras-chave: Demand and Price Analysis; Productivity Analysis.
Ano: 1994 URL: http://purl.umn.edu/22427
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Damaged Goods: A resource depletion model of addictive consumption AgEcon
Tregeagle, Daniel; Harris, Michael; Hertzler, Greg.
Economic research on the consumption of harmful goods focuses principally on the addictive nature of consumption rather than its impacts on health, despite medical research showing that consumers primarily consider health effects when making decisions about addictive behaviour. In this paper, the standard rational addiction model is recast in terms of a resource depletion problem, where the resource in question is a depletable stock of health, and the time horizon is finite. Analysis of the prototype health depletion model finds two types of consumption path, one that is compatible with the results from rational addiction and one that is not. Several extensions to the prototype model are explored.
Tipo: Conference Paper or Presentation Palavras-chave: Resource /Energy Economics and Policy.
Ano: 2011 URL: http://purl.umn.edu/100723
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Dynamic Contingent Valuation and Choice Modelling for Ecosystem Services AgEcon
Hertzler, Greg.
Non market valuation and bio economic modelling are combined in a dynamic model of ecosystem services. A mathematical proof demonstrates that the imputed price of natural capital contains all non market values and that scarcity rent is the total value of ecosystem services. A dynamic demand system, including characteristics is derived. New methods are developed for dynamic welfare analysis and both revealed and stated preference methods are proposed for estimating the price of natural capital. Estimation is simple if we avoid surveying consumers who degrade the ecosystem and instead consult owners who accrue the scarcity rent and conserve for the future.
Tipo: Conference Paper or Presentation Palavras-chave: Non market valuation; Ecosystem services; Lancaster demand; Welfare analysis; Analytical solutions; Demand and Price Analysis; Environmental Economics and Policy; Research Methods/ Statistical Methods; Q57; Q51; Q56.
Ano: 2008 URL: http://purl.umn.edu/6024
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DYNAMICALLY OPTIMAL AND APPROXIMATELY OPTIMAL BEEF CATTLE DIETS FORMULATED BY NONLINEAR PROGRAMMING AgEcon
Hertzler, Greg.
Cattle purchasing, feeding, and selling decisions are described by a free-time optimal control model. The nutrient constraints of the National Research Council and a recently published dry matter intake constraint augment the model and make it nonlinear in the feed ingredients, the daily gain, and the weight of the cattle. Optimal feeding programs are calculated by nonlinear programming under two scenarios: first, when the feedlot has excess capacity and, second, when animals must be sold to make room in the feedlot before more can be purchased. An approximately optimal feeding program is calculated by nonlinear programming and is all but identical to the dynamically optimal programs.
Tipo: Journal Article Palavras-chave: Livestock Production/Industries.
Ano: 1988 URL: http://purl.umn.edu/32165
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Livestock Dynamics: An Old Problem and Some New Tools AgEcon
MacAulay, T. Gordon; Hertzler, Greg.
A problem encountered in the econometric estimation of dynamic models of livestock systems is dynamic instability during simulation of models. In the case of systems where economic decisions are involved in the breeding and the slaughter of animals it is possible for parameters to be obtained which generate dynamic instability. In the paper, a simple representation of the dynamics of a livestock system is examined using techniques of dynamic analysis. The dynamic stability of such models depends fundamentally on the parameters determining the births and deaths and thus the relative flows in and out of the stock of animals. In some situations very narrow stability ranges for the values of the parameters are observed.
Tipo: Presentation Palavras-chave: Dynamic models; Beef herd; Dynamic instability; Dynamic processes; Livestock Production/Industries.
Ano: 2000 URL: http://purl.umn.edu/123699
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Managing and Sharing the Risks of Drought in Australia AgEcon
Carter, Chris; Crean, Jason; Kingwell, Ross S.; Hertzler, Greg.
Tipo: Conference Paper or Presentation Palavras-chave: Resource /Energy Economics and Policy.
Ano: 2006 URL: http://purl.umn.edu/25319
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Measuring Social Welfare: A Dog’'s Hind Leg Possibility Postulate AgEcon
Hertzler, Greg.
Our current methods of analysing policies and the distributions of wealth insure that society is on an efficient frontier. This is not the same as a social optimum. To choose the optimal point on the frontier we need a social welfare function. Following the ordinal revolution in demand theory, a large body of research concluded that social welfare functions don't exist. The intensity of people's preferences cannot be observed and hence interpersonal comparisons are essentially impossible. This paper argues that the intensity of people's preferences can be observed and could be incorporated into a social welfare function.
Tipo: Conference Paper or Presentation Palavras-chave: Social welfare; Welfare analysis; Demand systems; Duality; Dynamic optimisation; Consumer/Household Economics; D60; D63.
Ano: 2007 URL: http://purl.umn.edu/10386
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Modelling Farm Households in a Spatial Context: Vietnamese Agriculture AgEcon
MacAulay, T. Gordon; Hertzler, Greg.
In this paper a model is developed which brings together elements of the household models, spatial trading systems and demand systems with elements of production and income risk. Some of the implications of the design are analysed. The design is focussed on the problem faced by Vietnamese farm households as they face land use policy changes which will allow for the possibility of land consolidation, reduced input subsidies and increased market risk.
Tipo: Presentation Palavras-chave: Consumer/Household Economics; Farm Management.
Ano: 2000 URL: http://purl.umn.edu/123701
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Optimal Dynamic Management of Agricultural Land-Uses: An Application of Regime Switching AgEcon
Doole, Graeme J.; Hertzler, Greg.
The capacity of global agricultural production to meet increased demand for food from population growth and wealth accumulation is threatened by extensive land degradation. Nonetheless, previous research has focused primarily on the dynamic implications of input management and ignored land-use choice. This paper extends this theory through an examination of the intertemporal management of agricultural land through the use of non-crop inputs, such as fertilizer, and land uses that either degrade or restore productivity. The need to consider the relative total asset value of alternative crops over time is demonstrated. Moreover, higher output prices for degrading crops are shown to increase their relative value, motivating the later adoption of substitutes....
Tipo: Journal Article Palavras-chave: Crop sequences; Land degradation; Regime switching; International Development; Production Economics; Q15; Q24.
Ano: 2011 URL: http://purl.umn.edu/100643
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The impact of price and yield risk on the bioeconomics of reservoir aquaculture in north Vietnam AgEcon
Petersen, Elizabeth H.; Hertzler, Greg; Schilizzi, Steven.
A bioeconomic model of reservoir aquaculture in northern Vietnam is used to investigate the impacts of price and yield risk on the level, variability and skewness of expected net revenue and utility. Prices and yields are assumed to follow lognormal and beta distributions, respectively. Net revenue follows a generalized gamma distribution and is found to be very risky compared with similar enterprises elsewhere, mainly due to the relatively high yield risk. This represents the nascent nature of the industry in Vietnam and the opportunity for efficiency improvements. Increasing production capacity (through increasing reservoir size, stocking density, production cycle length and harvest rate) are found to increase profits and decrease the variability of...
Tipo: Conference Paper or Presentation Palavras-chave: Bioeconomic modelling; Price risk; Yield risk; Aquaculture; Vietnam; Resource /Energy Economics and Policy.
Ano: 2007 URL: http://purl.umn.edu/10422
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The Precautionary Principle in Practice: How to Write a Call Option on the Environment AgEcon
Hertzler, Greg.
Tipo: Presentation Palavras-chave: Environmental Economics and Policy.
Ano: 2000 URL: http://purl.umn.edu/123660
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Valuing Western Australia’s Recreational Fisheries AgEcon
Zhang, Jing; Hertzler, Greg; Burton, Michael P..
Australia by using the data from the newly finished National Survey of Recreational Fishing (2000/2001)(NSRF). There are a number of findings. 1. Socio-economic characteristics of anglers didn’t affect their catch of high quality fish (prize fish, reef fish or key-sport fish) as much as their catch of low quality fish (table fish and butter fish). 2. For a given trip, anglers were willing to pay $1.63, $26.03, $1.03 and $0.53 for the first prize fish, reef fish, key-sport fish or butter fish caught, respectively. 3. The top four valuable fishing sites in the survey period were Geraldton, Esperance, Albany and Broome, with annual access values of $6.45 million, $4.52 million, $3.47 million and $2.47 million, respectively. 4. The per trip estimates are of...
Tipo: Conference Paper or Presentation Palavras-chave: Recreational fishing; Random utility model; Non-market valuation; Production Economics; Research Methods/ Statistical Methods.
Ano: 2003 URL: http://purl.umn.edu/58275
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Weather Derivatives and Yield Index Insurance As Exotic Options AgEcon
Hertzler, Greg.
This paper develops methods to quantify weather derivatives and yield index insurance. These are exotic options that differ from financial options in several ways. The underlying random variable is not a price but a quantity such as millimeters of rainfall. Instead of option "pricing", a method must be developed for option "quantifying". Financial options are tradable. Weather derivatives and yield index insurance are not. Instead of being priced continuously, these are quantified once when the contract is written. As a result, they are less flexible. Financial options are linear. The probability distribution of an option is easily found from the probability distribution of the underlying price. Yield index insurance is a contract written on a non-linear...
Tipo: Conference Paper or Presentation Palavras-chave: Financial Economics.
Ano: 2004 URL: http://purl.umn.edu/58705
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