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| Registros recuperados: 34 | |
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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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| Meyer, Stefan; Yu, Xiaohua; Abler, David G.. |
| Using Monte-Carlo simulation, , we compare the most popular demand systems including the LES, AIDS, BTL, QES, QUAIDS and AIDADS, and find that different models actually have different advantages in estimating different elasticities. Specifically, QES, AIDS and AIDADS models are the best in income, own-price and cross-price elasticities, respectively. Overall, AIDADS model has the best performance. The results indicate that the rank three models are not necessary always better than the rank two models. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Comparison; Demand Systems; Monte Carlo; AIDS; Consumer/Household Economics; Demand and Price Analysis; Research Methods/ Statistical Methods. |
| Ano: 2011 |
URL: http://purl.umn.edu/103736 |
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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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| 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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| Petrolia, Daniel R.. |
| Corn stover harvest and transport cost functions were estimated for two harvest operations for a proposed biomass-to-ethanol conversion facility located in southern Minnesota, USA. This work presents an alternative methodology to estimating corn stover quantities and harvest costs at the county level, taking into account county-specific yields, transportation distances, erosion constraints, machinery specifications, and other key variables. Monte Carlo simulation was also used to estimate the probability distribution of costs under alternative assumption on key parameters whose values vary widely in the literature. Marginal stover cost for 50MM gal/year of ethanol output was estimated at $54/dt ($0.77/gal ethanol) for the more intensive harvest method... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Biomass; Corn stover; Economics; Ethanol; Lignocellulose; Monte Carlo; Crop Production/Industries; Resource /Energy Economics and Policy. |
| Ano: 2006 |
URL: http://purl.umn.edu/14213 |
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| Kovacs, Sandor; Ertsey, Imre; Balogh, Peter. |
| In order to analyse risks and to choose from different decision-making strategies simulation models are often applied in several areas of animal breeding. We developed an improved Monte Carlo model for analysing laying hen breeding combined with Bayes statistics. On the basis of data from a company breeding broiler parents, our paper examines the technological and economic risks of breeding a laying-hen stock with a simulation program developed by our team. During modelling we take individual cost elements and the most significant factors (different forage costs, price of sold eggs, unsuitable eggs, installing day-old chicks and old animals) affecting returns into consideration. The results can be presented in tables and graphs for both sexes as well.... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Monte Carlo; Risk analysis; Chicken production; Bayessian statistics; Foraging; Livestock Production/Industries. |
| Ano: 2007 |
URL: http://purl.umn.edu/7798 |
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| Linacre, Nicholas A.; Thompson, Colin J.. |
| The successful management of transgenic technology is likely to depend on the economic behavioral response of farmers to the regulated use of transgenic crops. A well-studied example is the widespread use of Bt-corn, in the United States, and elsewhere, to control the European Corn Borer, a major corn pest. The extensive use of Bt-corn has led to concerns about the emergence of insect resistance. The United States Environment Protection Agency addressed this potential problem by developing an insect resistance management strategy, based, in part, on complex mathematical models using detailed biological assumptions about the population genetics and life history of the European Corn Borer. However, seed companies and others have sometimes used simpler... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Insect resistance; Monte Carlo; Bt-corn; Logistic growth; Environmental risk; Biotechnology; Environmental protection; Crop Production/Industries. |
| Ano: 2005 |
URL: http://purl.umn.edu/59239 |
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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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| Registros recuperados: 34 | |
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