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Using tools for modelling and solving agricultural problems under risk

COMPUTERS AND ELECTRONICS IN AGRICULTURE 1999年第2-3期22卷 187-197页

作者： Pecher, A Hahn, S Univ Newcastle Upon Tyne Fac Agr Dept Agr Econ & Food Mkt Newcastle Upon Tyne NE1 7RU Tyne & Wear England Univ Halle Wittenberg Fac Agr Inst Agr Econ & Rural Dev D-06099 Halle Germany

We present an opportunity to use a combination of computer based tools for generating risk functions, simulation, classical decision rules and linear programming (LP) as tools for decision making. This new approach is demonstrated by the use of an example which addresses the optimal assemblage of a pig fattening enterprise, whereby some basic data (e.g. prices, labour costs and average daily weight increases) are risk functions. Some coefficients, especially in the objective function (maximum gross margin) are stochastic values calculated with those 'risky' basic data. Various scenarios for different cases of risk behaviour are formulated and solved using decision rules. The optimal LP results are interpreted in deterministic and stochastic ways. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： correlation decision rules fattening pigs likelihood linear programming models risk functions simulation

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Survey of mathematical programming models in air pollution management

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 1997年第1期96卷 1-35页

作者： Cooper, WW Hemphill, H Huang, Z Li, S Lelas, V Sullivan, DW TEXAS NAT RESOURCES CONSERVAT COMMISS OFF AIR MONITORING OPERATAUSTINTX 78711 ADELPHI UNIV NEW YORKNY 11530

This paper surveys the current state of the literature in management science/operations research approaches to air pollution management, After introducing suitable background we provide some of the institutional and legal framework needed to understand the continuing regulatory efforts in United States. Attention is then turned to mathematical programming models ranging from fairly simple deterministic linear programs to quite sophisticated stochastic models which have appeared in the literature dealing with these topics, This is followed by extensions reflecting some of the work we have undertaken in association with the Texas Natural Resource Conservation Commission, a regulatory agency in Texas, Application and potential use of models is the central theme of this survey, Issues for future research are presented at the end and an extensive list of publications is provided in the references at the end of the article. Principal air quality issues of local, national, and international concern are listed below in increasing order of difficulty based on the number of different types of pollutants and problems in quantification of the risks the pollutants pose: 1. Stratospheric ozone depletion: one relatively easily controllable class of trace gases - ozone depleting chemicals, or ODCs, principally chloroflurocarbons (CFCs) - with relatively well quantified risks;2. Criteria pollutants: six common pollutants - ozone (O-3), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), lead (Pb), and particulate matter less than 10 microns in size (PM10) - regulated since 1970 in the U.S. and presenting relatively well quantified risks;3. Acid precipitation: two relatively easily controllable classes of trace gases - oxides of nitrogen (NOx) and oxides of sulfur (SOx) with relatively well quantified risks;4. Global warming/climate change: a few difficult to control trace gases - principally carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and CFCs - with hi

关键词： Optimization methods publications Integer programming models Pollutant mathematical programming linear programming models trace gases pollution management

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Understanding linear programming modeling through an examination of the early papers on model formulation

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OPERATIONS RESEARCH 1997年第3期45卷 341-356页

作者： Murphy, FH Panchanadam, V SCHNEIDER LOGIST INC GREEN BAYWI

We use the models of cognitive psychology and the early literature on linear programming models to understand how experts organize their thinking about models. We show that several different patterns appear in the way models are related to each other. This paper also is a kind of cognitive history of the formulation of linear programming models in the first decade after the invention of the field.

关键词： linear programming Cognitive models Economic models Semantic networks Physics Mathematical models linear programming models Semantic models Algebra

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How successful was Edwards' linear programming model for marmots?

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OECOLOGIA 1997年第3期112卷 331-332页

作者： OwenSmith, N Centre for African Ecology Department of Zoology University of the Witwatersrand Private Bag 3 Wits 2050 South Africa Fax: +339-3407 e-mail: norman@gecko.biol.wits.ac.za ZA

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A programming model and system infrastructure for real-time synchronization in distributed multimedia systems

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1996年第1期14卷 249-263页

作者： Blair, GS Coulson, G Papathomas, M Robin, P Stefani, JB Horn, F Hazard, L CTR NATL ETUD TELECOMMUN F-92131 ISSY MOULINEAXFRANCE

One of the major requirements of distributed multimedia applications is the need to maintain often complex, real-time synchronization constraints, More specifically, it is necessary to be able to manage arbitrary intra- and inter-media synchronization across activities in the distributed environment. Furthermore, it is important that such developments are integrated into emerging object-oriented standards for distributed computing. This paper presents an object-oriented programming model and associated implementation to meet these requirements. The main concepts behind the proposed approach are, firstly, the use of reactive objects for real-time control and synchronization and, secondly, quality of service controlled bindings for predictable communication between objects, The flexibility of the approach is demonstrated by three contrasting examples of real-time synchronization. The implementation extends the realtime capabilities of the Chorus micro-kernel by introducing the concepts of rtports, rthandlers and quality of service controlled connections, The paper demonstrates how reactive objects and bindings are realized on this infrastructure.

关键词： distributed multimedia system INFRASTRUCTURE Real time control Integer programming models real-time synchronization clock recovery MULTIMEDIA APPLICATION MULTI-MEDIA SYSTEM linear programming models Quality of service

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A 2N CONSTRAINT FORMULATION FOR THE CAPACITATED MINIMAL SPANNING TREE PROBLEM

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OPERATIONS RESEARCH 1995年第1期43卷 130-141页

作者： GOUVEIA, L UNIV LISBON DEPT STAT & OPERAT RESP-1699 LISBONPORTUGAL

In this paper we present a new formulation for the Capacitated Minimal Spanning Tree (CMST) problem. One advantage of the new formulation is that ii is more compact (in the number of constraints) than a well-known formulation. Additionally, we show that the linear programming relaxation of both formulations produces optimal solutions with the same cost. We present a brief discussion concerning valid inequalities for the CMST which are directly derived from the new formulation. We show that some of the new inequalities are nor dominated by some sets of facet-inducing inequalities for the CMST. We derive some Lagrangian relaxation-based methods from the new formulation and present computational evidence showing that reasonable improvements on the original linear programming bounds can be obtained if these methods are strengthened by the use of cutting planes. The reported computational results indicate that one of the methods presented in this paper dominates, in most of the cases, the previous best methods reported in the literature. The most significant improvements are obtained in the instances with the root in the corner.

关键词： Lagrangian function Optimal solutions linear programming Algorithms Heuristics Port capacity linear programming models Approximation Transmission lines Integers

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AN ALGORITHM TO GENERATE RADIAL BASIS FUNCTION (RBF)-LIKE NETS FOR CLASSIFICATION PROBLEMS

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NEURAL NETWORKS 1995年第2期8卷 179-201页

作者： ROY, A GOVIL, S MIRANDA, R Arizona State University USA

This paper presents a new algorithm for generating radial basis function (RBF)-like nets for classification problems. The method uses linear programming (LP) models to train the RBF-like net. Polynomial time complexity of the method is proven and computational results are provided for many, well-known problems. The method can also be implemented as an on-line adaptive algorithm.

关键词： RADIAL BASIS FUNCTION-LIKE NETS CLASSIFICATION PROBLEMS linear programming models

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USTED - A METHODOLOGY FOR A QUANTITATIVE-ANALYSIS OF LAND-USE SCENARIOS

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NETHERLANDS JOURNAL OF AGRICULTURAL SCIENCE 1995年第1期43卷 5-18页

作者： STOORVOGEL, JJ SCHIPPER, RA JANSEN, DM WAGENINGEN UNIV AGR DEPT DEV ECON6706 KN WAGENINGENNETHERLANDS

Scenarios are a useful tool to study the effects of changes in the socio-economic and/or biophysical environment on agricultural land use. For the analysis of these scenarios an operational methodology, denominated USTED, has been developed. The methodology is based on a linear programming model in combination with GIS, crop growth simulation models, and expert systems. The data requirements include quantitative descriptions of land use systems and technologies, attribute data on e.g. prices and chemical compositions, and georeferenced data on farms and soils. Sustainability is incorporated in the methodology by a limited number of quantified sustainability parameters. The linear programming model analyses, on the basis of different farm types, the effect of different scenarios on land use. Customized computer software (MODUS) operationalises the integration of the different models. The methodology is illustrated with a case study for the Neguev settlement in the Atlantic Zone of Costa Rica.

关键词： COSTA RICA GIS LAND USE SCENARIOS linear programming models SUSTAINABILITY

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OPTIMAL MIX OF TECHNOLOGIES FOR RURAL INDIA - THE IRRIGATION SECTOR

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INTERNATIONAL JOURNAL OF ENERGY RESEARCH 1991年第4期15卷 331-346页

作者： SINHA, CS KANDPAL, TC Tata Energy Research Institute 7 Jor Bagh New Delhi 110003 India Centre for Energy studies Indian Institute of Technology Hauz Khas New Delhi 110016 India

In India and other developing countries, irrigation has received particular attention for stimulating economic growth. Increase in agricultural productivity through better inputs is considered the key to economic development and self sufficiency. Considering the cost increases incurred by the state-run electricity utilities in rural electrification and the uncertainties pertaining to the supply and the price of liquid hydrocarbon fuels, it becomes imperative to identify other options for irrigation water pumping. Much work has been done in recent years in India and elsewhere on the use of alternative technologies for this purpose, and the present work attempts to develop a linear (mixed integer) model for determining the cost-effective technology options at the micro level. The energy required for irrigation is estimated. This is followed by a mathematical description of the developed model. The authors also discuss the technoeconomics of different energy resource and technology options for the irrigation sector. The technologies include solar photovoltaics, water pumping windmills, gasifier and biogas plants coupled to diesel engines operating in the dual-fuel mode, electric pumpsets, and diesel pumps in the independent mode. The developed model is solved for typical conditions that exist in India, and it is shown that there are conditions in which alternative energy technologies make economic sense.

关键词： RURAL ENERGY IRRIGATION DECENTRALIZED ENERGY TECHNOLOGIES linear programming models

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HEURISTIC SOLUTION PROCEDURES FOR A MIXED-INTEGER programming DISCRIMINANT MODEL

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MANAGERIAL AND DECISION ECONOMICS 1990年第4期11卷 255-266页

作者： RUBIN, PA MICHIGAN STATE UNIV GRAD SCH BUSINESS ADM E LANSING MI 48824 USA

Focuses on heuristic solution procedures for a mixed-integer programming discriminant model. Comparison between mixed-integer programming models and linear programming models' accuracy; Use of the Monte Carlo simu... 详细信息

关键词： Heuristics Discriminants linear programming Sample size Variable costs Zero linear programming models Integer programming

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