Volume 06

This volume of Journal of Cybernetics and Informatics (JCI) focuses on modelling, optimization, process control and application of information technologies in practice. The included papers study the topics of multicriterial synthesis in hybrid control structures, genetic algorithm applications, software safety and reliability and production planning and control. The application part of this volume concentrates on the implementing conventional and soft techniques in drive control and in other industrial fields.

This article deals with importance of safety issues in computer programming. Secure software can only be designed with security as a primary goal. To achieve that we would have to redesign our computer systems with security in our mind including entire computer environment, e.g. hardware, programming languages and, of course, operating systems. In software development process the quality of resulting computer code should be the most important aspect during the whole program development process. Simplicity of the code in computer programs pays off.

In this paper, a direct field-oriented induction motor drive with a sliding mode controller (SMC) is presented. The (SMC) technique finds its stronger justification in the utilization problem of a robust nonlinear control law to model uncertainties. The used control algorithm is sliding mode associated with a particular function "sat" to limit chattering effects that presents a serious problem to applications of variable structure systems.

This paper uses an ant system (AS) meta-heuristic optimization method to solve the problem of structure optimization of series-parallel production systems. In the considered problem, redundant machines (elements) and buffers in process are included in order to attain a desirable level of reliability. A procedure which determines the minimal cost system configuration is proposed. In this procedure, multiple choices of producing machines and buffers are allowed from a list of product available in the market.

The existing methods of multicriterial synthesis of logistics systems (LS) have been developed and improved according to the complex of technical and economic indications. Capabilities of procedures of scale evaluation and evaluation of the coordination of expert opinion have been expanded, what increased the efficiency of problems solutions on LS synthesis with the quantity and quality criteria.

This paper aims at demonstrating possibilities of genetic algorithms application in speed controller design for a vector control of induction motor. The basic procedure to develop a genetic algorithm is described and the examples of its application using different quality criterions are introduced. Then a possibility to consider various disturbances in calculating optimal controller parameters, e.g. change of load torque is analysed. Finally, a possibility to use genetic algorithm for a design of parameters of IP speed controller is described.