Journal Issue: 1/2012

The first Issue in the year 2012 of the journal ICCST is out. In the Issue you can read about the state of the art Bulgarian scientific researches by the leading researchers in the following subject areas: Process Control, Comunication technologies, Pattern Recognition, Signal Processing Itelligent System Control, Image and Spectral Analyses and more.

Possibilities Application of Fractional Operators in Industrial Control

Authors: E. Nikolov.

One essentially new class of fractional ML-DTC control systems is proposed in the work. It is configured through combinations of strategy repetitive control, dead-time compensation control and fractional control. Repetitive control is an effective strategy for periodic disturbances suppression by filtering their influence into the control system, assuming that the period of disturbances is known. The use of fractional dead-time compensators in the systems gives advantages in quality control of i...

Analysis and Evaluation of Errors in Training and Testing of Recognition Systems

Authors: Chavdar Iv. Damyanov.

The choice of measures for evaluating the quality of recognition systems and classifiers is an object of attention of researchers from various areas of application: Bioinformatics, Educational Testing, Machine Learning and different Measurement Techniques. The problem of how to choose objective measures for evaluating the quality of classifiers is not trivial, and there is no universal solution. Up to now, different measures of evaluating the quality of classifiers have been used in the engineer...

PID Control Systems with Maximum Gain Margin

Authors: L. Tomov, Ts. Slavov and E. Garipov

Novel sub-optimal easy to apply tuning rules for maximum gain margin control are derived for PID controllers. The approximated solutions obtained after optimization and simplification by Symbolic Toolbox of MATLAB are compared with well-known design methods.

PAPR Reduction of OFDM Signals Using Modified Partial Transmit Sequences

Authors: Mihail P. Iliev, Borislav Y. Bedzhev, Viktor V. Hadzhivasilev, and Stoyan S. Yordanov

Partial transmit sequences (PTS) is an effective technique for reducing the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing signals. However, the conventional PTS technique requires an exhaustive searching of the optimal phase factors over the all possible combinations of values. Due to this reason the computational complexity increases exponentially with the number of the sub-blocks and it is difficult the conventional PTS to be used in practical systems. With r...

Modeling and Simulation of a Handover Priority Scheme with RESTART

Authors: Dimitar Radev , Elena Ivanova, Rostislav Raev and Svetla Radeva

The processes of changing the channel associated with the current connection while a call is in progress is under consideration. The estimation of dropped calls is received with modelling and simulation of handover with three level priority scheme. Blocking calls at base station channels and handover queues overflow is simulated with RESTART. The simulation algorithm is worked out and simulation program is realized on Visual C++. Simulation results are shown.

Method for Synthesis of Signals Possessing Ideal Periodic Autocorrelation Function and Small Alphabet

Authors: Borislav Y. Bedzhev, Mihail P. Iliev, Stoyan S. Yordanov , Viktor V. Hadzhivasilev

A key role for the present wireless communications plays the families of signals with low periodic correlation (LPC). With regard in the paper a new method for synthesis of signals, possessing both ideal periodic autocorrelation function (IPACF) and small alphabet, is presented. The method is based on a modification of the maximal length sequences (M – sequences) and increases significantly the density of the set of the possible signal lengths. Besides, the method can be developed for synt...

Intelligent System for Control of Biological Wastewater Treatment Based on Benchmarking of Cases

Authors: Kosta Boshnakov, Zdravko Georgiev

The topic of the present work is the increasing of supervisory control efficiency of biological wastewater treatment through Case-Based Reasoning. For the purpose periodical benchmarking of the cases in concrete clusters is applied by using Data Envelopment Analysis. Modification of the classical R4 cycle of Case-Based Reasoning is implemented. Example of benchmarking of cases done by data envelopment is presented.

Implementation and Experimental Studies of Broadband Transmission Line Transformers

Authors: Boyan Karapenev.

This paper presents a method of implementation and experimental results obtained from studies of broadband transmission line transformers in the frequency response of their used ferrite toroidal cores with coefficients of resistant ratio nz 1:1, 4:1 and 1:4. Some transformers are practically implemented with 3 and 5 twists per 1 cm of pair copper enamelled wires with ferrite toroidal cores manufactured by the firm Amidon FT82-xx and FT114-xx of materials 77, 61 and 43. The obtained results &ndas...

Design of a Collocated Robust Controller for a Flexible-Link Manipulator

Authors: Georgi Lehov, Petko Petkov

Tip-position control problem of a single-link flexible manipulator moving in the horizontal plane in the presence of parametric uncertainties is considered in this paper. A collocated two-degree-of-freedom robust controller using joint angle feedback only is designed via the µ-synthesis. The analysis shows that the robust controller ensures very good tip motion performance and efficiently suppresses the elastic vibrations during fast motions of the manipulator for wide ranges of uncertaint...

Using Kendall’s Coefficient of Concordance to Identifying PhD Research Problems in University of Ruse

Authors: Georgi Krastev, Tsvetozar Georgiev, Evgeniya Georgieva, Silian Arsov

In this report is examined a preliminary investigation of some problems which the PhD students from the University of Ruse meet during their research work. A methodology of the investigation is proposed and a special questionnaire including 17 statements is developed. In the conducted survey 37 PhD students participated. A calculations and data analysis are made, the obtained results are shown and the corresponding conclusions are done.

Complex Assessment of Dairy Products using Color Images and Spectral Analyses

Authors: Emanuil Dimitrov, Mirolyub Mladenov

The paper provides an overview and analysis of known methods and solutions for quality assessment of dairy products based on color images and NIR spectral analysis. The main features of quality, safety, and healthiness of Bulgarian white brine cheese and Bulgarian kashkaval are specified. An overview of the possibilities for express and non-destructive assessment of basic dairy products quality features by color images and spectral analysis is done. It is made a proposal of a complex assessment ...