A. A. Abaidulin PROBLEMS OF INCREASING EFFICIENCY OF TELECOMMUNICATION SYSTEMS OPERATION IN EMERGENCY SITUATIONS

A. A. Abaidulin PROBLEMS OF INCREASING EFFICIENCY OF TELECOMMUNICATION SYSTEMS OPERATION IN EMERGENCY SITUATIONS

The analysis of emergency situations, both in Russia and abroad, has shown the necessity of creating conditions for coordinated interaction of various logistics services of Civil Defense (CD) with other ministerial and departmental authorities. In providing such conditions, the status and efficiency of CD control system operation in localization and liquidation of the consequences of emergency situations, the ability of this system to interact with its counterparts in other ministries, departments and services, are of special importance.

The analysis of control system status demonstrates that communication systems, computer-aided control and decision-making systems of various departments, in general, have weak interconnection, both organizationally and technically. This has a negative influence on the efficiency of implementation of functional target tasks by CD services. Therefore, there arises a necessity of creation and introduction of systems, complexes of computer-assisted control and communication, which would ensure solution of these problems.

Specifics of the tasks of CD services presuppose their deployment in regions devoid of any stationary telecommunication systems. This creates additional demand of mobility and efficiency of the organizational and technical structure of computer-aided control and communication systems. It is necessary to note that the above problems because of a number of circumstances can not be resolved quickly, and require integrated study.

The paper contains the results of research of the following problems:

• 
  optimization of the structure of mobile integrated message-switching centers;
  
• 
  design of the structure of mobile computer-aided control and decision-making system;
  
• 
  design of interaction protocols of communication facilities and computer-aided control systems;
  
• 
  software structure of the automated mobile message-switching centers is presented;
  
• 
  results of research of increasing efficiency of decision making by computer-aided control systems and of implementation of these decisions;
  
• 
  optimization of frequency spectrum selection for operation of various communication facilities and complexes has been conducted.
  

A. A. Abaidulin, Yu. I. Beresnev SIMULATION OF INFORMATION PROTECTION SYSTEMS IN DISTRIBUTED INFORMATION PROCESSING NETWORKS

Along with development of telecommunications technology and creation of distributed information processing networks (IPN) based on the above technology, the problems of information security become more and more urgent.

IPN information protection systems (IPS) are complex systems, having multi-level character, complexity of infological links, and a great number of indeterminancies existing in these systems [1].

In order to design IPS and research their operation, it is necessary to build models, which would correspond to existing IPN and describe the process of information protection with sufficient completeness. One of the most reasonable approaches to formalizing processes of IPS operation is to use Petri nets and their problem-oriented extensions. The models built on the basis of Petri nets apparatus as well as their implementation algorithms, are oriented on various classes of information processing networks. They allow to take into account topological features and specifics of information processing network verification methods.

The structure of Petri nets represents a bipartite multigraph and consists of a set of positions and transitions. The oriented arcs connect positions and transitions, where some arcs are directed from positions to transitions, and others - from transitions to positions. The set of positions can determine a set of system conditions, while transitions represent some actions and processes, taking place in the system. The oriented arcs determine input and output positions of this or that transition. Petri nets marking is used to determine the order of launching this or that transition. It can have different functional meaning, that is why the concept of polychromatic marking is introduced [2]. By means of marking it is possible to represent this or that resource of a system being simulated.

Thus, in terms of Petri nets it is possible to describe IPS operation in sufficient detail. The main purpose of IPS analysis, interpreted in terms of Petri nets, is to determine the presence or absence of various properties of a process being simulated.

Petri nets possess certain properties, including security, boundedness, keeping quality, activity, accessibility, coverability [2]. On the basis of the analysis of a simulation object as to conformity to the above-stated properties, it is possible to draw a conclusion on the necessity of reconfiguring a project or an existing system.

The Petri net methods set can be used both for designing IPS and for the analysis of an existing system.

The system constructed is simulated by a Petri net, and then the model is analyzed. Any difficulties encountered during the analysis indicate defects of the given system. In order to correct them, it is necessary to modify the project. Then the modified project is again simulated and analyzed. Simulation and analysis process is repeated until a positive result is reached.

In Fig. 1, a fragment of the description of a local area network (LAN) user authentification subsystem in terms of Petri nets is shown.

1. 
   L. M. Ukhlinov. Problems of Data Security in Information Processing Networks. // Open Systems. -1995. – No. 3 (11). - Pages 12-14.
   
2. 
   D. L. Peterson. The Theory of Petri Nets and System Simulation.-Moscow: Mir, 1984, 264 pages