Wyniki wyszukiwania - Biblioteka Nauki

1

Fitness-distance analysis of a car sequencing problem

100%

Kubiak M. , Jaszkiewicz A. , Kominek P.

Foundations of Computing and Decision Sciences

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2006

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tom Vol. 31, No. 3-4

263-276

EN

The paper describes a fitness-distance analysis of a car sequencing problem. It defines 5 similarity measures for solutions of the problem, describes computational experiments and provides values of determination coefficients between fitness and similarity, which are an indicator of fitness-distance correlation (or 'big valley'). The analysis reveals certain correlations of fitness and two types of similarity for 4 of 5 types of available instances. This results might motivate such designs of metaheuristics for these types of instances which would exploit the structure in fitness landscapes.

2

Optimisation of crop rotations : A case study for corn growing practices in forest-steppe of Ukraine

100%

Romashchenko M. , Bohaienko V. , Shatkovskyi A. , Saidak R. , Matiash T. , Kovalchuk V.

Journal of Water and Land Development

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2023

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tom no. 56

194--202

EN

The formation of optimal crop rotations is virtually unsolvable from the standpoint of the classical methodology of experimental research. Here, we deal with a mathematical model based on expert estimates of “predecessor-crop” pairs’ efficiency created for the conditions of irrigation in the forest-steppe of Ukraine. Solving the problem of incorporating uncertainty assessments into this model, we present new models of crop rotations’ economic efficiency taking into account irrigation, application of fertilisers, and the negative environmental effect of nitrogen fertilisers’ introduction into the soil. For the considered models we pose an optimisation problem and present an algorithm for its solution that combines a gradient method and a genetic algorithm. Using the proposed mathematical tools, for several possible scenarios of water, fertilisers, and purchase price variability, the efficiency of growing corn as a monoculture in Ukraine is simulated. The proposed models show a reduction of the profitability of such a practice when the purchase price of corn decreases below 0.81 EUR∙kg-1 and the price of irrigation water increases above 0.32 EUR∙m-3 and propose more flexible crop rotations. Mathematical tools developed in the paper can form a basis for the creation of decision support systems that recommend optimal crop rotation variations to farmers and help to achieve sustainable, profitable, and ecologically safe agricultural production. However, future works on the actualisation of the values of its parameters need to be performed to increase the accuracy.

3

Combined optimisation and MCDA based solution of the tram depot location problem

51%

Sawicki P. , Sawicka H.

Archives of Transport

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2021

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tom Vol. 60, iss. 4

88--103

EN

This paper deals with an issue of technical facilities location in a public transport system. The decision problem is formulated as a selection of the most advantageous alternative, i.e. the location of a new tram depot among the already existing facilities of this type. The selection is preceded by the evaluation of the alternatives. The assessment is not a trivial task, because there are many groups of interest with usually contradictory points of view. Therefore, the evaluation of the new tram depot locations should represent different aspects, e.g., economical, technical, environmental, and organizational. To handle such a complex decision problem the authors propose a methodology, which is a composition of the optimisation and multiple criteria evaluation techniques. The developed methodology is experimentally applied to the selection of one out of five tram depot locations in the public transport system of the city of Poznan, Poland. All the computational experiments are performed by means of optimization and multiple criteria decision aiding (MCDA) methods and tools, i.e. a linear optimization engine Solver Premium Platform and AHP method with its application AHORNsimple. The calculations are the basis for recommending the location of a new depot in the central part of the transport system network, which is a reasonable solution taking into account, e.g. the proximity of the main railway line, the possibility of triple distribution of the transport means from depot. The proposed methodology of the decision problem solution gives also an opportunity to create the hierarchy of considered tram depot locations as well as to compare the position in the ranking of the best solution with the existing one. Since the proposed methodology assumes the selection of the most suitable MCDA method to the problem under consideration and the decision maker’s preferences, it guarantees that the result of analysis becomes reliable and the decision aiding process is credible.

4

Declarativity in modelling and problem solving

51%

Niederliński A.

Control and Cybernetics

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2000

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tom Vol. 29, no 1

325-339

EN

The paper discusses a new trend in the modelling software for combinatorial and mixed combinatorial-continuous decision problems. The trend, aiming at solving those problems by the simple activity of properly describing them, is best exemplified by a constantly inereasing spectrum of Constraint Logic Programming (CLP) languages. The first such language was Prolog. After a short historical survey concentrating mainly on Prolog, main characteristics of a modern, commercially successful CLP language - CHIP - are presented, discussed and illustrated. The CLP approach to problem solving is compared with traditional Operation Research approaches.