SESSION 6 OTHER APPLICATIONS OF INTERACTIVE SYSTEMS

SESSION 6 OTHER APPLICATIONS OF INTERACTIVE SYSTEMS

Robert Löw, Jeanne Stynes, Ingo Stengel, Aidan McDonald DISTRIBUTED HIERARCHICAL DIRECTORY SERVICE FOR ENTERPRISE COMPUTING

In large enterprises the efficient administration of employees information is very difficult. It is very costly to keep and to look after such information. Keeping information at places, where they are used, promise simplification of care and higher actuality.

Indeed these information are needed not only locally but also in the whole trust. Several systems have been used to process employee information. It is the goal of this paper to give a view on the integration of information holding infrastructures to a single infrastructure / service.

All applications should be able, using standardised techniques, to handle employee information. After a detailed requirement analysis, considering the rising security problems, this paper will show the different approaches to solve this problem, with their specific advantages and disadvantages. It will discuss the central directory service approach versus the distributed directory service. After that we will point out the concept of our approach, the distributed hierarchical directory service (DHDS). Using existing standards (LDAP / X.500) it will provide location transparency (an application does not need to know where the requested information is stored) and a flexible and expandable information infrastructure. The DHDS is a combination of the central and the distributed directory service. It integrates existing information infrastructures (e.g. the network information service (NIS)).

Using a prototypical implementation, the discussed solution is evaluated at the moment on its functionality in large financial enterprises.

B.G.Ibrahimov Intellectual Terminal Complexes in the Information-Computer Communication Networks

At present development of information-computer communication networks ICCN based on the new computer technologies, monomedia, multimedia, Frame Relay ATM (Asynchronous Transfer Mode) and ISDN issues of establishing Intellectual Terminal Complexes ITC for interactive exchange of speech and non-speech information obtains a large actuality. Transmission from one regime into the other one is automatically carried out during the work process with the help of RTP protocol working in the regime of multimedia, which was realized under the base of terminal element of management by applying expert system.

It is known [1,2] that ICCN is made under the base of ITC by using expert system for the collective use of sources of interactive exchange, division and processing of information. ITC - multifunctional and intellectual types of terminals. ICCN was build by the module device-program principle by applying hybrid expert systems providing high effect of system, interactive digital multimedia services. Investigating composition of the physical structure of ICCN consists of communications network, ITC and communication channels (CC). Algorithm of functioning ICCN is explained in [2] and it is represented in the form of open mass services system (MSS) for the investigation of probable-time characteristics.

In order to solve this problem in the given work issues of optimal functioning ITC in ICCN are revised.

It was defined that the scheme and model of MSS ICCN and its physical structure is describe by the following graphics:

T=(T_k, N_k), T_k={1,2,…,N}, N_k={N_ij}, i, j=1,…,N, ij,

where T_k - great number of nodes, which is ITC, N_k - border means CC.

Under the base of this graphics, the analyze shows that optimal functioning of ICCN under the base of ITC is characterized by the effective use of TC and CC which are optimized both by two parameters as an average time delay T_sz, and given economical expenses Q_c, which is described as follows:

max max [T_sz, Q_c] min

Here with analyze and synthesis of ICCN shows that for the optimization of structure and characteristics of system should follow the below-mentioned conditions: T_i (x) min, in condition that T_i (x) < T_доп, Q_ci (x) min_, in condition that Q_ci (x)< Q_доп. In this case the whole function may be recorded in the following way:

T (x)=minmax T_i (x)/T_доп, Q_c (x)=minmax Q_ci (x)/ Q_доп,

where T (x) - an average time delay of system; Q_c (x) - given economical expenses for ICCN; T_доп - maximal allow meaning of an average time delay of system; Q_доп - maximal allow meaning of given economical expenses.

After it two main characteristics T_i (x) and Q_ci (x) are reviewed for the rational investigation of ITC in ICCN. Under the base of it they optimized characteristics in the form of function are recorded by the following way:

F (T, Q_c)=minmax [T_i (x)/T_доп, Q_ci (x)/ Q_доп]

Now let’s review mathematical models for the formalized description of ICCN under the base of ITC which characterizes information processing realized into data communication network with commutation of packets (CP) and there was fixed that MSS is M/G/1. Let us assume that ITC and (1, 2, …, N) N_k communications channels which are interpreted as MSS M/G/1 and M/M/1. Nodes of ITC implement the operations for the commutation of packets, collection-dispatch of packets, information processing, including their editing, buffering, election of routes and etc. Two streams of traffic enter into each node: external with intensity _i from ITC connected to this node and internal with intensity _j from other nodes of ICCN. Serving discipline is “FIFO”. There are turns to the communications channels. Delays are appearing during the transmission of traffic data. In this case, intensity of packets in ICCN is defined by the following expression:

Under the base of physical structure and model of functioning ITC in ICCN, an average time of delay in the network is summarized from the delays in the nodes of ITC and communications channels which are defined as follows:

where N_k - number CC, external from i-m of nodes; T_ij (cc) - an average time delays of CC between i-m and j-m nodes; T_i (тс) - an average time delays of in the ITC i-m of nodes; _ij - summarized intensity of packets between i-m and j-m of nodes communications.

So, the results of investigations and analyze show that optimal functioning of ITC in ICCN allows to promote the efficiency of electronic mail system X.400, FR services, services for the interactive exchange of video-information, interactive speech and processing of the documents under the base of multimedia services, interactive video service.

References

1. 
   Kleinrock L. Computing Systems with Queues. Moscow. : Mir. 1979-pp. 600.
   
2. 
   Ibrahimov B.G. Effectiveness and noise Stability Terminal Complexes System Telecommunications. Baku, “ELM” . 1998- pp. 256 .