Leoneed Kirilov

A Survey of Solving Approaches for Multiple Objective Flexible Job Shop Scheduling Problems

Abstract Many real life scheduling problems can be formulated as Flexible Job Shop Scheduling Problems (FJSSPs) which simultaneously optimize several conflicting criteria. A typical feature of such problems is their high computational complexity. The purpose of this paper is to provide a review of the techniques, developed to solve multiple objective FJSSPs during the last decade. These techniques could be classified into two groups: approaches with application of mathematical models and heuristic approaches. Usually hybrid metaheuristic algorithms are proposed for large dimensional real life problems and they outlay the tendency for the future developments of efficient solution approaches for multiple objective FJSSPs.

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.

Web-based decision support system in regional water resources management

Decision support systems (DSS) have a great theoretical potential as tools for the identification of optimal water resource management regimes in river catchments, thus helping policy makers to bring the principles of integrated water resources management into practice. The paper considers a WEB-based approach to DSS construction to help water resources management. The operational system and technical architectures of DSS in water resources management are briefly described on the grounds of the necessary functionality that has to ensure such system. The main elements of such system are presented for management of surface water in a river catchment.

Multiple Criteria Approach to Solving Problems of Metal Building-Up by Welding

Abstract The problem of process optimizing of metal building-up by welding is investigated. A multiple criteria model with four objectives is suggested. To model the process parameters, a planned experiment has been carried out. The interactive satisfying trade-off method (STOM) of Nakayama is used to solve the model.

A lexicographic ordering approach in multiple criteria decision support

A method for solving nonlinear Multiple Criteria Decision Support Problems (MCDSP) is presented. The dialog with the Decision Maker (DM) is in terms of aspiration levels in the objective space. In the phase of computation, a lexicographic problem is used to generate a number of efficient points. The proposed method gives the possibility to the DM to investigate the whole efficient set, including the improperly efficient points.

Simulated Annealing Method for Metal Nanoparticle Structures Optimization

The goal of this paper is to develop an efficient method to search for metal and bimetal nanoparticle structures with the lowest possible potential energy. This is a global optimization problem. In computational complexity theory, global optimization problems are NP-hard, meaning that they cannot be solved in polynomial time. Because of the severe difficulty of finding the global minimum, the simulated annealing algorithm was selected as main strategy. At the first step we use the lattice Monte Carlo method with different lattices. Then we relax the resulting nanoparticle structures at low temperature within molecular dynamics, choosing one of them as approximation of the global minimum. The numerical solution of an optimal cluster structure of Ag (200) shows the efficiency of the proposed method.

An extension of flexible job shop problem (FJSP) and method for solving

The problem of scheduling arises in many real life situations. The job shop scheduling problem is very often used model and very actively studied. Two main formulations are used: job shop problem (JSP) and flexible job shop problem (FJSP). FJSP is more complex and more adequate model than JSP. A generalization of FJSP is presented in this paper. A heuristic method is proposed to solve it, using the make-span as objective function.

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.

Computer modeling of watershed runoff with data for the Mesta river

An investigation of a computer model for rainfall runoff process of the Mesta river watershed is presented in this paper. The model is based on the HEC-HMS (Hydrologic Modeling System) software. Different methods incorporated in HEC-HMS are analyzed and the suitable ones for constituting an adequate hydrologic model of the Mesta river are selected. The final model consists of eleven basic elements of the subbasin type. An analytical approach for reporting on the influence of the snow precipitation over the runoff is suggested. Also a way to model the daily data on the basis of cumulative monthly data is discussed.