Algorithmical and topological methods of fault tolerance assurance

Special interest in designing, constructing and exploitation of fault tolerant systems is connected with the need of attending to critical infrastructure systems. In this paper we focus on presentation and analysis of the requirements demanded on the context of fault tolerance assurance in the critical infrastructure systems. Especially, we take into consideration algorithmical and topological methods of fault tolerance assurance

A novel approach to fault tolerant multichannel networks designing problems

This work presents solution of a bus interconnection network set designing task on the base of a hypergraph model. In order to do this the interconnection network is presented as a multipartite hypergraph. A system with virtual bus connections functioning in an environment of common physical channel was analyzed, which is characteristic of the networks based on the WDM technology. The mathematical reliability model was proposed for two modes of system functioning: with redundancy of communication subsystem and division of communication load. As solution estimation criteria the expected changes of processing efficiency changes were used as also a communication delay change criteria and system reliability criteria. The designing task solution is searched in a Pareto set composed of Pareto optima. The selection procedure of a specific solution in the case of its equivalency in relation to a vector goal function was presented

Operating system efficiency evaluation on the base of measurements analysis with the use of non-extensive statistics elements

The major goal of this article was to evaluate the efficiency of Linux operating systemusing statistical self-similarity and multifractal analysis. In order to collect the necessary data, thetools available in Linux such as vmstat, top and iostat were used. The measurement data collected withthose tools had to be converted into a format acceptable by applications which analyze statistical selfsimilarityand multifractal spectra. Measurements collected while using the MySQL database systemin a host operating system were therefore analyzed with the use of statistical self-similarity and allowedto determine the occurrence of long-range dependencies. Those dependencies were analyzed with theuse of adequately graduated diagrams. Multifractal analysis was conducted with the help of FracLabapplication. Two methods were applied to determine the multifractal spectra. The obtained spectrawere analyzed in order to establish the multifractal dependencies

Designing of multichannel optical communication systems topologies criteria optimization

This paper presents the issues necessary to solve in the designing process of multichannel optical communication systems topologies. The main design assumption is the acceptance of mul-tichanneling in communication system realization. In particular, the basics of designing physical and logical topologies are shown. Also cost aspects of physical and logical topologies realization are shown

Performance Analysis of VPN Remote Access Tunnels

The purpose of the study is to analyze the efficiency of communication with the serverusing the methods of secure remote access, as well as checking and comparing the quality of servicesprovided by the server depending on the method of secure remote connection. The article focuses onVPN technology implemented in the latest Windows Server 2012 R2 operating system

Long-range dependencies in reading memory pages in the man-computer system interaction

The modern computer systems consist of many interdependent subsystems. There are two possible approaches to their analysis. The first one is based on the idea of reductionism proposed by Descrates[1] and can be considered as a still ruling paradigm in the case of computer science and engineering. The second one can be related to the still new idea of the complex systems approach, where in order to understand the behaviour of such systems one needs to have the knowledge about the behaviour of system components and also, that is more important, how they act together [2, 3, 4, 5, 6, 7, 8]. This specific paradigm change can be even shown in the case of the idea of Turing machines and new approach for consideration in the case of interactive processing – even the opinion that “the computer engineering is not a mathematical science” was presented [9]. It should be noted that the Turing machine is a mathematical idea [10] while its implementations are the physical ones [11], but if the physical nature of computer systems was indicated, there is a need to have an appropriate physical (thermodynamical) basis for deliberations in such a case. In [12] it has been shown that the analysis of processes in the computer systems can be based on non-extensive thermodynamics. However, this analysis considers only spatial correlations, meanwhile in this paper we will focus on time dependencies leading to a long-memory effect. The paper is divided into 5 sections. In Section 2 the conception of the hierarchical structure of memory system in the computer is presented. This proposal was given in [11] where its influence on computer thermodynamics was discussed. In Section 3 there is a short survey about long-range dependencies whereas Section 4 discusses practical usage of theoretical considerations. The last section concludes the paper

Computer network traffic analysis with the use of statistical self-similarity factor

The optimal computer network performance models require accurate traffic models, which can capture the statistical characteristic of actual traffic. If the traffic models do not represent traffic accurately, one may overestimate or underestimate the network performance. The paper presents confirmation of the self-similar nature of the selected protocols in the computer network communication layer. It shows that the good measure of self-similarity is a Hurst factor

Simulation of reconfiguration problems in sensor networks using OMNeT++ software

The paper presents a comparative analysis of reallocation algorithms in a structure of wireless sensor network in the event of a failure of network nodes. The article contains detailed research results of wireless sensor networks technology, with particular emphasis on thte network-layer protocols - routing protocols. In the research the simulation environment OMNeT++ was used to study the properties of reconfiguration and reallocation problems in the wireless sensor networks

Models of multichannel interconnection systems

This work begins with presentation of modern teleinformatic systems functional problems. The authors indicate the necessity of using the multichannel communication technologies. Next, the building and exploitation costs analysis of interconnection systems was shown. Methodology of including designing system exploitation costs during the designing process was proposed. In the last part of the work the model allowing to design teleinformatic systems with expanded interconnection network more efficient was presented

Sensor network infrastructure for intelligent building monitoring and management system

The aim of this study was to present that it is possible to design and implement an efficient and functional intel-ligent building management system based on free tools, own project and self-realization of sensor network sys-tem which may be a low cost alternative to commercial ones. The paper presents the designed system consisting of implemented devices on the basis of sensor network technology and own hardware project in a building manage-ment system. At the application level there was designed and implemented the building management system which allows communication between the sensors, data exchange between the sensors and the database as well as the system parameters visualization panel used for intelligent building monitoring