Volume 13 (2013): Issue 4 (December 2013)
The publishing of the present issue (Volume 13, No 4, 2013) of the journal “Cybernetics and Information Technologies” is financially supported by FP7 project “Advanced Computing for Innovation” (ACOMIN), grant agreement 316087 of Call FP7 REGPOT-2012-2013-1.

An estimation approach that allows recovering of the traffic state is proposed in this paper. The method used is based on numerical differentiation, which does not need any integration of differential equations and turns out to be quite robust with respect to perturbations and measurements noises. Numerical simulations, carried-out by using the so-called Cell Transmission Model (CTM) demonstrate the relevance of the proposed on-line estimation scheme.

The operation of a complex system like a transportation network is considered with respect to the opportunities to identify the application of autonomic properties. The autonomic features of self-properties are analyzed. A multilevel approach is suggested for the formalization of the transport operation. The integration of relevant optimization problems is also considered in the framework of a multilevel, hierarchical scheme of control. The application of bi-level formalism in the transportation systems gives quantitative assessment of the control processes in the traffic control system. The multilevel approach allows the increase of the solution space of a complex optimization problem with an additional traffic control variable, which in the classical optimal formalization participates with fixed parameters in the optimization problem. The benefit of the multilevel control approach is tested in a real network of crossroad sections.

This paper aims at developing a risk index based on real-data measurements, which can be used either off-line as an evaluation index during the evaluation process which leads to the dramatical reduction of the field test periods, or in real-time like: a safety monitoring tool (e.g. safety user warning system), or a multi-criterion function to be optimized in real time (safety index combined with a traffic index) within several control strategies, such as coordinated ramp metering, speed limit control, route guidance, etc.

: An essentially new class of repetitive fractional disturbance absorptive filters in disturbances absorbing control systems is proposed in the paper. Systematization of the standard repetitive fractional disturbance absorptive filters of this class is suggested. They use rational approximations of the operators for fractional integration in the theory of fractional calculus. The paper discusses the possibilities for repetitive absorbing of the disturbances with integer order filters and with fractional order filters. The results from the comparative analysis of their frequency characteristics are given below.

Analytical deriving has been realized to obtain the second order Payne model from the first order Lighthil-Witham-Richards model.

The aim of this paper is to propose an approach for quality assessment and efficiency of the web-based system for distance learning. This system has useful options for on-line creation and use of Web-based courses by other medical disciplines in Medical University - Sofia. The results of the assessment will be used to improve the functionality of the processes in the system to meet the user requirements.

The necessity of new approaches for structural synthesis of mechanical systems, which directly identify a limited number of structures that carry a potential for solving the technical problems and meet the specific requirements for the design of mechanical systems, mainly for specialised robots, is specified. The identified five types of kinematic chains (primary, parallel, secondary, additional and subsidiary), with different functionality, allow the synthesis of manipulators structures according to the defined goal tasks and specific functional requirements for hybrid systems, in particular specialised industrial robots. Two mechatronic approaches for functional structural synthesis of mechanical systems of industrial robots, where the main manipulation mechanism is a path generator, were introduced. A limited number of structures that meets the set of objectives and technical requirements to design mechanisms, is directly determined. Emphasis is placed on the tasks of passive (mechanical) control of manipulation systems associated with specialized robotics. Two mechatronic approaches for functional structural synthesis of mechanical systems of industrial robots, where the main manipulation mechanism is a motion generator, are introduced. A limited number of structures is directly defined that meets the set of technical objectives and requirements for the designed mechanisms. Emphasis is placed on the tasks of passive control of the manipulation systems associated with the specialized robotics.

The proteins are one of the most important part of the organisms. They are complex macromolecules that perform a vital function in all living beings. They are composed of a chain of amino acids. The biological function of a protein is determined by the way it is folded into a specific 3D structure, known as native conformation. The protein folding problem is a fundamental problem in computational molecular biology. The high resolution 3D structure of a protein is the key to the understanding and manipulating of its biochemical and cellular functions. Protein structure could be calculated from knowledge of its sequence and our understanding of the sequence-structure realizations. Various methods have been applied to solve the protein folding problem. In this paper the protein is represented like a sequence over a 3-letter alphabet according to the specific functions of amino acids. After that the folding problem is defined as an optimization problem. Our protein model is multifunctional. It can be used to predict the 3D structure of the protein from its amino acid sequence. The model can predict the changes in the protein folding when several amino acids are mutated. A protein can be constructed by it with the needed 3D folding. In this paper we have concentrated on predicting protein folding changes when some amino acids are mutated.

Mobile agent technology has become an important approach for the design and development of distributed systems. Currently, there is little research regarding the efficiency of mobile agent-based monitoring of the server resource. Based on the Mobile-C library, a mobile agent-based system called Mobile Agent- Based Server Resource Monitoring System (MABSRMS) is presented. In MABSRMS mobile agents can call low level functions in binary dynamic or static libraries, and thus can monitor server resource conveniently and efficiently. The experiment was conducted in a university computer center with hundreds of computer workstations and 15 server machines. The experiment uses the MABSRMS to detect system resources, such as available hard disk space, CPU usage and main memory usage. The experiment shows that the mobile agent-based monitoring system is a practical way to monitor server resources in large scale distributed computer centers.

In rough set theory, the number of all reducts for a given decision table can be exponential with respect to the number of attributes. This paper investigates the problem of determining the set of all reductive attributes which are present in at least one reduct of an incomplete decision table. We theoretically prove that this problem can be solved in polynomial time. This result shows that the problem of determining the union of all reducts can be solved in polynomial time, and the problem of determining the set of all redundant attributes which are not present in any reducts can also be solved in polynomial time.

In the process of inter-domain handover, according to the partner-based hierarchical mobile IPv6 protocol (PHMIPv6), the longer configuration time for a new care-of-address may cause an interrupt in the current wireless connections and cause higher handover latency and packet loss rate. This paper proposes an improved handover mechanism based on PHMIPv6, named B-CDHO. A fPN and bPN are defined respectively in B-CDHO as cooperative relay nodes during the handover process. fPN can get the new care-of-address instead of a mobile terminal before the handover triggers and bPN can avoid connection interrupt if the prehandover time is longer. The analysis and simulation results both show that B-CDHO can reduce the handover latency and packet loss in comparison to HMIPv6 and PHMIPv6 in case the pre-handover delay is longer.

The output voltage of Solid Oxide Fuel Cell (SOFC) is usually changed with the temperature and hydrogen flow rate. Since the fuel cell can generate a wide range of voltages and currents at the terminals, as a consequence, a constant DC voltage and function cannot be maintained by itself as a DC voltage power supply source. To solve this problem, a simple SOFC electrochemical model is introduced to control the output voltage. The Sliding Mode Control (SMC) is used to control the output voltage of the DC-DC converter for maintaining the constant DC voltage when the temperature and hydrogen flow rate are changed. By the simulation results it can be seen that the SMC technique has improved the transient response and reduced the steady state error of DC voltage.