Krassimira Genova

An approximate algorithm for nonlinear integer programming

Abstract This paper suggests an approximate algorithm, designed to solve nonlinear integer problems. This algorithm belongs to the class of component algorithms of feasible integer directions. The search for a feasible integer direction is done on the basis of a linear approximation of the objective function and the constraints at the integer points under consideration. Theoretical analysis is presented, as well as experimental investigation, using the algorithm for test examples taken from the literature.

An algorithm of internal feasible directions for linear integer programming

Abstract An approximate algorithm for solving pure integer problems is examined. The algorithm belongs to the class of component algorithms using feasible integer directions. The basic characteristics of the algorithm are analyzed. Testing on an IBM/PC/AT personal computer is carried out. The proposed algorithm is compared with other well known approximate algorithms.

TRASY -- An automated system for real-time control of the industrial truck haulage in open-pit mines

Abstract The control of truck haulage in open-pit mines is an essential problem in the production process of the mines. We describe an automated system for real-time control of the haulage vehicles in terms of the underlying models and solution procedures and we report on the experiences with the system in a real industrial environment.

A prototype of a web-based decision support system for building models and solving optimization and decision making problems

A prototype of a Web-based software system for optimization and multiple criteria decision making, applicable to business, research and learning purposes is presented. The system facilitates the construction of mathematical models and the solution of some popular real optimization and decision making problems. It has user friendly interface designed for different groups of users. The system software is accessible from anywhere by means of a standard browser and an Internet connection.

Generalized Scalarizing Model GENS in DSS WebOptim

A web-based Decision Support System WebOptim for solving multiple objective optimization problems is presented. Its basic characteristics are: user-independent, multisolver-admissibility, method-independent, heterogeneity, web-accessibility. Core system module is an original generalized interactive scalarizing method. It incorporates a number of thirteen interactive methods. Most of the known scalarizing approaches (reference point approach, reference direction approach, classification approach etc.) could be used by changing the method’s parameters. The Decision Maker (DM) can choose the most suitable for him/her form for setting his/her preferences: objective weights, aspiration levels, aspiration directions, aspiration intervals. This information could be changed interactively by the DM during the solution process. Depending on the DM’s preferences form the suitable scalarizing method is chosen automatically. In this way the demands on the DM’s knowledge and experience in the optimization methods area are minimized.

A Reference Neighbourhood Interactive Method for Solving a Class of Multiple Criteria Decision Analysis Problem

Abstract An interactive method intended to solve multiple criteria decision analysis problems with a large number of discrete alternatives and a few criteria is proposed in the paper. The decision-maker (DM) sets his/her local preferences in terms of desired or acceptable changes in the criteria values for some criteria and the desired or acceptable change of directions for a few of the remaining criteria. A small ordered set of relatively “close” alternatives is defined with the help of a scalarizing problem. If required by the DM, this set is ranked by a formal procedure on the basis of the local intra- and intercriteria information provided by him/her. The ranked set is presented to the DM who selects the most preferred alternative or enters his/her new preferences for improving the current alternative. The software realization of the interactive method proposed is included in an experimental decision support system called MultiChoice for solving multicriteria analysis problems.

Linear multicriteria decision support system

The paper presents a multicriteria decision support system, designed to model and solve linear problems of multicriteria optimization. The system is developed on the basis of an interactive classification-based algorithm, which allows the decision makers describe their local preferences with the help of desired and acceptable levels, directions and intervals of change in the values of a part or of all the criteria.The structure and the users interface of the system are described.