Level

Date

 Not chosen  

 20.4.2006 

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.

 Not chosen  

 20.4.2006 

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. Extra options and features can result in unmanageable complexity. For computer security purposes, program modularization is of a paramount importance and it seems to be the only way how to properly cope with complexity. Internal consistency of the whole program should be frequently checked via assertions. They are the best way to check parameter validity coming from other program units e.g. modules. Especially each module must distrust everything else coming from other modules and/or from the user. Frequently used code optimizations are classicly leading to some sort of redundant code options and features and thus indirectly causing a useless code complexity. Extensive testing of programs is necessary for finding possible bugs in programs. However it does not locate security holes in the system. Standard software implementation techniques are completely inadequate in the production of a secure code. Consequently an introductory programming course as a college course should be taught in parallel with introductory security of computer systems, since it is too late to teach it as an elective at the end of computer science curriculum. In general, security of computer systems and programming should not be separated as two different and separate disciplines instead they should be integrated together.

 Not chosen  

 20.4.2006 

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 elements of the system are characterized by their cost, estimated average up and down times, productivity rates and buffers capacities. The reliability is defined as the ability to satisfy the consumer demand which is represented as a piecewise cumulative load curve. The proposed meta-heuristic is used as an optimization technique to seek for the optimal design configuration. The advantage of the proposed AS approach is that allows machines and buffers with different parameters to be allocated.

 Not chosen  

 20.4.2006 

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. Simulation tests under load disturbances and parameter uncertainties are provided to evaluate the consistency and performance of the proposed control technique.

 Not chosen  

 20.4.2006 

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.

 Not chosen  

 20.4.2006 

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.