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  • The task of determining the optimal reactivity distributed information processing systems at a fixed cost of their downtime

    In this article, in terms the language of queuing networks, the problem is formulated finding the optimal value the average response time of the system to the requests all users for distributed information processing systems implemented on the basis of the file-server architecture, two-level and three-level client-server architecture with a fixed cost of downtime, including the cost downtime for users, the cost of downtime for a data transmission channel and the cost downtime for service nodes. An algorithm for solving this optimization problem is presented.

    Keywords: distributed information processing system, file-server architecture, two-level client-server architecture, three-level client-server architecture state space, average system response time, loss cost, stationary probabilities

  • Mathematical model of optimal placing information resources is solved on distributed information systeme on the basis of three-lewel client server arhitecture without cosidering the influence of blocings

    Using a device of close homogeneous exponential queueing networks (QN) a mathematical model of an distributed information system functiouning for solving the problem of getting integral indexis on the basis of local computing network on the basis of three- level client server arhitecture. The base correlation for transitione matrix probabilities constraction and intensitiese of service at the network nodes are given.The peculiarity of the model being worked out is in making a selective choice of information at the database servers and via the channel of communication not the full data base is transmitted but some separate parts of it, which satisfy the conditions of SQL-request search.

    Keywords: Distributed information system, distributed data base, local computing system, mass service network, conceptual model, exponential law of distributing the random value, stationary probability, mark process, the global balance equation, system reaction tim

  • Software implementation of models of optimal allocation of information resources

    This article describes the stages of implementing the program to solve the task of calculating the average response time of a distributed information processing system to user requests and an algorithm for the optimal distribution of information relations over the nodes of a distributed information processing system implemented on the basis of a file server architecture and a two-tier client server architecture, with and without locks. The procedure for constructing the initial data for modeling is described: the elements of the matrix of the initial distribution of information resources (relations) over the nodes of the distributed information processing system, the elements of the matrix of information interrelation between the requests of users of the distributed information processing system and the information resources themselves, the elements of the matrix of probabilities for generating queries by users. A procedure has been developed and programmed to significantly simplify the calculation of the normalizing constant, and accordingly the average response time of the system to user requests. The results of numerical experiments are presented

    Keywords: Distributed information processing system, file-server architecture, two-level client-server architecture, nonlinear combinatorial optimization, generator of equiprobable choice, Jordan-Gauss method, normalized constant, average reaction time of the syste

  • Heuristic algorithm for solving the problem of optimal allocation of information resources .

    In this article to solve the problem of optimal distribution of information resources over the nodes of distributed inorganic system according to the criterion of minimum of the medium time, the response of the system to the requests of the users an original heuristic algorithm is proposed that uses the notion of databases as points of a mulltidimensional space, but about nodes in which these bases are placed as clasters. The resuts of numerical experiments are presennted depending on the architecture of the distributed system used and on the method of ensuring data integrity. Numerical experiments showed rather high efficiency of the proposed algorithm.

    Keywords: Distributed information system, distributed data base, local computing system, mass service network, non-lineare combinatorial optimization, query generation, a matrix of probabilities for generating queries by users, a matrix for distributing relations a

  • Mathematical model of functioning distributed infomatione systeme on the basis of three-lewel client server arhitecture .

    Using a device of close homogeneous exponential queueing networks (QN) a mathematical model of an distributed information system functiouning for solving the problem of getting integral indexis on the basis of local computing network on the basis of three- level client server arhitecture. The base correlation for transitione matrix probabilities constraction and intensitiese of service at the network nodes are given.The peculiarity of the model being worked out is in making a selective choice of information at the database servers and via the channel of communication not the full data base is transmitted but some separate parts of it, which satisfy the conditions of SQL-request search.

    Keywords: Distributed information system, distributed data base, local computing system, mass service network, conceptual model, exponential law of distributing the random value, stationary probability, mark process, the global balance equation, system reaction tim