Papers by Ivan Mustakerov
ABSTRACT The increasing competitiveness in manufacturing industry is forcing manufacturers to see... more ABSTRACT The increasing competitiveness in manufacturing industry is forcing manufacturers to seek effective processing schedules. The paper presents an optimization manufacture scheduling approach for dependent details processing with given processing sequences and times on multiple machines. By defining decision variables as start and end moments of details processing it is possible to use straightforward variables restrictions to satisfy different technological requirements and to formulate easy to understand and solve optimization tasks for multiple numbers of details and machines. A case study example is solved for seven base moldings for CNC metalworking machines processed on five different machines with given processing order among details and machines and known processing time's duration. As a result of linear optimization task solution the optimal manufacturing schedule minimizing the overall processing time is obtained. The manufacturing schedule defines the moments of moldings delivery thus minimizing storage costs and provides mounting due-time satisfaction. The proposed optimization approach is based on real manufacturing plant problem. Different processing schedules variants for different technological restrictions were defined and implemented in the practice of Bulgarian company RAIS Ltd. The proposed approach could be generalized for other job shop scheduling problems for different applications.
The paper presents an evaluation of the time needed for the development of an e-Learning course a... more The paper presents an evaluation of the time needed for the development of an e-Learning course as an essential part of e-Learning development costs. Two quantitative methods are proposed: one-factor regression analysis method and modified parametrical modeling method. The parametrical modeling method is extended by introducing of a set of more precise indicators together with their respective weight coefficients. The application of these methods can be used as preliminary planning of the e-Learning course development costs.
Expert Systems With Applications, 2011
The paper describes a conceptual approach for development of educational Web-based e-testing syst... more The paper describes a conceptual approach for development of educational Web-based e-testing system. The system aims to improve the effectiveness of the learning process by providing features for flexible adjusting of the testing process. The tutors and learners can interact with the e-testing system by choosing different options for testing -easy questions, advanced questions, sequential or shuffle order, random generated questions within given range. The e-testing system can be used by students for self-testing or by tutors for official examination. When used for official examination the test results information is sent to the examiner by e-mail. The system files are stored on the server-side and are accessible through Webbrowser. A prototype of e-testing system illustrating the proposed approach is developed by means of HTML and JavaScript languages. It was used for ''C Programming Language'' course students self-testing and official examination. The experimental results demonstrated that the implementation of the proposed approach is quite helpful to facilitate the understanding and implementation of teachers' attitudes toward Web-based e-testing tools application.
Applied Mathematical Modelling, 2009
The paper describes a generalized optimization method for night vision devices (NVDs) design taki... more The paper describes a generalized optimization method for night vision devices (NVDs) design taking into account stochastic external surveillance conditions -ambient light illumination, atmosphere transmittance, contrast between target and background and target type. The main idea of the presented method is optimizing of the NVD design process by optimal choice of the optoelectronic channel modules -objective, image intensifier tube, ocular and electrical battery power supply while considering the influence of the external surveillance conditions uncertainty. For that goal a stochastic nonlinear mixed-integer multicriteria optimization problem is formulated and solved. The problem solution gives the optimal modules combination and some preliminary estimation about the operational characteristics of the designed NVD -working range (consistent with the uncertainty of the external surveillance conditions), weight, price and electrical batteries power supply operational duration. An illustrative numerical example based on the optimal choice from sets of objectives, image intensifier tubes, oculars and electrical batteries types is solved. The described method increases the effectiveness of the NVD design.
ABSTRACT The problem of technical devices evaluation and choosing is not easy decision making pro... more ABSTRACT The problem of technical devices evaluation and choosing is not easy decision making process. The technological development and the availability of many different technical solutions with different performance parameters specify complex combinatorial choice problems. The night vision devices (NVD) have become quite popular recently and are an example of complex technical choice with conflicting performance parameters. The paper describes important NVD parameters that should be considered and a multicriteria optimization approach for smart NVD choice. The proposed approach uses popular weighted sum method to comply with different user preferences by defining relative weights among NVD parameters considered as objective functions. The practical applicability of the proposed approach has been demonstrated by some case study examples of choosing night vision goggles satisfying different user preferences. Real set of devices offered on Internet are used to formulate and solve optimization tasks reflecting user's preferences. The proposed multicriteria choice approach can be used for all types of night vision devices and other technical devices also to make a smart choice corresponding to decision-makers preferences and restrictions.
... 1 Introduction The advance of information and communication technologies makes e-learning the... more ... 1 Introduction The advance of information and communication technologies makes e-learning the focus of the modern education society. ... The current paper describes a new framework approach for low cost developing of customized Web-based multimedia e-learning system ...
Renewable Energy, 2010
The paper addresses the problem associated with the optimal wind park design. A combinatorial opt... more The paper addresses the problem associated with the optimal wind park design. A combinatorial optimization model for wind turbines type and number choice and placement considering the given wind conditions and wind park area is developed. The wind park investment costs and the total power relation as function of wind turbines number and type are used as optimization criteria. The optimization problem is formulated as a single criterion mixed-integer nonlinear discrete combinatorial task. The different wind park conditions are introduced into optimization tasks formulation as variables relations and restrictions. Two basic wind directions cases are taken into consideration -uniform and predominant wind directions for two wind park area shapes -square and rectangular. The developed wind park design approach was tested numerically by solving of different optimization tasks formulations based on wind turbines real parameters data. The numerical testing shows the applicability of the developed optimization approach. Using it will help to find mathematically reasoned wind turbines choice as contradiction to the heuristic approaches.
Uploads
Papers by Ivan Mustakerov