Systems and Means of Informatics scientific journal
Volume 24, Issue 3, 2014
MATHEMATICAL SOFTWARE TOOLS FOR ANALYTICAL MODELING IN STOCHASTIC SYSTEMS WITH COMPLEX NONLINEARITIES
Abstract: New mathematical software tools in "IDStS" are developed for differential stochastic systems (DStS) with Wiener and Poisson noises with complex finite, differential, and integral nonlinearities and hereditary StS (HStS) reducible to DStS. Algorithms of analytical modeling based on the normal approximation method (NAM) and the statistical linearization method (SLM) are given. Numeral and symbolic algorithms for NAM (SLM) are developed in MATLAB for typical nonlinearities in DStS. Test examples are given. Special attention is paid to the problems of analytical modeling in HStS with complex nonlinearities based on NAM and SLM.
Keywords: analytical modeling; complex finite differential and integral nonlinearities; complex irrational nonlinerarites; differential stochastic system with Wiener and Poisson noises; mathematical software tool "IDStS;" method of normal approximation; method of statistical linearization; hereditary stochastic systems reducible to differential
SECURE ARCHITECTURE OF DISTRIBUTED SYSTEMS
Abstract: Distributed components of an enterprise information system (IS) interact among themselves through a network, providing information about production activity of an enterprise or an organization. There is a class of vulnerabilities creating threats to correct and safe execution of the functions of IS. Often, hackers look for vulnerabilities using a malicious code which independently extends between hosts of IS while getting to the least protected nodes. Let V be the set of components of the distributed IS and E be the set of possible interactions between components, then G = (V, E) is the architecture of the distributed IS. The following decomposition of architecture of the distributed IS is considered as a hierarchy of architecture of classes of components. The architecture of the network of the distributed IS represents the bottom level of decomposition. The following levels of hierarchy are the architecture of applications and the architecture of information technologies. The top level of hierarchy is the architecture of the distributed IS. Architectural threats are the transit through hosts of the malicious code and information leakage through information technologies. Secure architecture is such architecture which within available means reduces risks of implementation of architectural threats. The architecture of IS is secured if there are no direct interactions between high- risky and high-valuable components. Necessary and sufficient conditions of existence of secure architecture of a distributed IS are found. It is defined under what condition it is possible to insert new tasks or information technologies to a distributed IS or to make other changes safely.
Keywords: information security of a distributed system; virtual system; risks; valuable information resources; architecture of a distributed information system
COVERT CHANNELS ON THE WIRELESS NETWORKS OF THE STANDARD 802.11
Abstract: The paper studies the possibility of building a covert channel using the header of the 802.11 standard frame and some features of functioning of wireless networks based on these standards. To construct a covert channel, the principles of a wireless network, the connection and disconnection processes of wireless clients, and the structure of the network frame have to be described. To confirm the possibility of using the header of the network frame and the mechanism of deauthentification of a wireless client for covert communication, the paper describes the layout, which includes the necessary hardware and software, and experiments. The experimental results confirm the possibility of building covert channels in 802.11 wireless networks. Authors propose a way of using covert channels described in the article as well as the methods of eliminating them.
Keywords: computer science; computer networks; wireless networks; information security; covert channels
FUSED MULTIPLY-ADD: METHODOLOGICAL ASPECTS
Abstract: The paper presents approaches to designing self-timed (ST) equipment and analyzes conditions of in-system integration of synchronous and ST units in a supercomputer network taking the ST Fused Multiply-Add (FMA) unit as an example. Self-timed FMA complies with the IEEE 754 Standard and performs either one double precision FMA operation or one or two single precision operations simultaneously under three operands. It utilizes the ST-ternary encoding and the 65-nanometer CMOS (complementary metal-oxide-semiconductor) technology as the implementation basis. Depending on realization, it works with asynchronous or synchronous environment and provides not less than 1 GFlops performance with latency not more than 6 ns with respect to input data arrival.
Keywords: self-timed circuit; supercomputer; fused multiply-add; adder; pipeline; energy efficiency
SELF-TIMED FUSED MULTIPLY-ADD UNIT: PRACTICAL IMPLEMENTATION
Abstract: Paper presents the results of designing Speed-Independed Fused Multiply-Add (SIFMA) variants compliant with the IEEE 754 Standard. SIFMA performs either one double precision FMA operation or one or two single precision operations simultaneously under three operands. SIFMA was designed for the standard 65-nanometer CMOS (complementary metall-oxide- semiconductor) technology. It uses both a standard cell library and a self-timed cell library designed in IPI RAS. One SIFMA variant operates with a synchronous environment, while another works with an asynchronous environment.
Keywords: self-timed circuit; ternary coding; multiplier; adder; subtracter; pipeline; indication
MODERN TRENDS IN EVOLUTION OF INTEGRATED NETWORK PROCESSOR
Abstract: The article points out the increasing role of programmable integrated network processors (INP) in developments of up-to-day packet switches, routers, and various devices for network infrastructure. The article gives an analysis of recent trends in INP architecture evolution and distinguishes different programmability levels and the most significant INP macroarchitecture components.
Keywords: integrated network processor; multicore processor; macroarchitecture; virtual pipeline; queue manager; high speed serial interfaces
TWO-PARAMETRIC ANALYSIS OF MAGNETIC-RESONANCE IMAGES BY THE MAXIMUM LIKELIHOOD TECHNIQUE IN COMPARISON WITH THE ONE-PARAMETRIC APPROXIMATION
Abstract: The paper considers a method of the two-parametric analysis of magnetic-resonance image's data which allows getting a joint estimation of both the useful signal and the noise within the image being analyzed on the basis of the maximum likelihood principle. This technique presents an essentially new approach to data processing in the conditions of the Rice distribution and can be efficiently used in information technologies for solving a wide range of tasks connected with the Rician signals' filtering. Solving the two-parametric task is based on measured samples' data only and is not connected with a priori suppositions concerning the noise value which inevitably limit the precision of the one-parametric method. By means of computer simulation, a comparative analysis of the traditional one-parametric method and the elaborated two- parametric method is made for estimation of the useful component of the signal forming the magnetic-resonance image. The statistical data for the shift and the spread of the sought-for signal and noise parameters are calculated. The advantages of the two-parametric technique of data analysis are shown.
Keywords: Rice distribution; likelihood function; maximum likelihood method; noise dispersion; signal-to-noise ratio
PROPERTIES OF WINDOW DISPERSION OF MYOGRAM AS A STOCHASTIC PROCESS
Abstract: Nowadays, the research of brain activity is conducted by many scientists. One of the approaches is the method of caused potentials: the testee repeats some actions, his brain activity and some additional signals are registered and then are analysed in order to detect necessary dependences. A number of works of the author and his collegues consider algorithms of localization of reference points in a myogram (and some other signals) corresponding to the movement beginnings in the experiment in which a person makes movements by a hand finger. Accuracy of localization of these points is critical for further processing of magnetoencephalogram. The paper covers some theoretical aspects of these algorithms such as models of a myogram and its window dispersion as stochastic processes.
Keywords: window dispersion; myogram; magnetoencephalogram
EXPERIMENTAL RESEARCH OF LABORATORY PROTOTYPE OF AN ARTIFICIAL HETEROGENEOUS SYSTEM FOR DIAGNOSIS OF ARTERIAL HYPERTENSION
Abstract: The paper contains the results of imitation of Virtual medical consultation for arterial hypertension diagnostics (functional hybrid system) by means of MATLAB 7 - Simulink and model experiments. The paper introduces the results of testing models from heterogeneous model field: functional modules for electrocardiogram recognition, for investigation of the module analyzing the data of daily monitoring of arterial pressure, and for classification of a patient's state of health; and also, technological modules for experimental utility estimation of symptomatic information for making a diagnosis by means of genetic algorithms. Experiments with laboratory prototype showed the opportunity of decreasing the threshold of "disguised and negotiating diagnosis" of arterial hypertension from 70% to 20% by using it in practice in medical and preventive treatment facilities of wide profile.
Keywords: laboratory prototype of virtual medical consultation; arterial hypertension; neural networks; genetic algorithms; fuzzy systems; functional hybrid intelligent system
THE PECULIARITIES OF NOMENCLATURE AND SPARE COMPONENTS QUANTITY COMPOSITION FOR SECURED AUTOMATED INFORMATION SYSTEMS
Abstract: Organizational and methodological problems of providing reliability for automation means complexes of secured automated information systems based on analysis, generalization, and evaluation of experience of supervisions on their operations are considered. The article shows some factors which determine lead-up and operational time of maintenance and repairs concerning electronic components. The suggestions regarding the structure of the spare parts list and the components quantity and their utilizations during repair work organization as like as four-level hierarchical structure are justified by the authors. Calculations of stock necessity of spare parts at the object are presented. Finally, there is an example of real calculations regarding quantity of necessary spare parts stock to achieve conditions of reliability.
Keywords: Secured Automated Information System; reliability; hardware failures; hierarchical principles; spare parts list; system recovery; sufficiency of spare parts parameter
THE PECULIAR PROPERTIES OF DOCUMENTATION DEVELOPMENT FOR SECURED AUTOMATED INFORMATION SYSTEMS
Abstract: The peculiar properties of documentation development for secured automated information systems (AIS) considering requirements of existing regulatory and technical base and experience of systems installation at customer's sites are described. The main system-technical and organizational problems concerning content of secured AIS documentation arising during implementation are determined. The paper suggests a systematic approach to presentation of secured AIS documentation content that is sufficient for development, deployment, and operation of secured AIS with necessary quality. The paper determines specialties of secured AIS and offers exact list of papers of working documentation developed for AIS. Finally, it is shown that suggested approaches are sufficiently effective for stuff education. The results are tested in practice in the process of creation and installation of several secured AIS.
Keywords: automated information system; working, development, and operational documentation
MONITORING OF INFORMATION SECURITY AS A CLOUD SERVICE
Abstract: The article considers aspects and issues of information security monitoring through systems SIEM (Security information and event management) as a service. Service is provided by the cloud data center. Quality assurance monitoring services in the cloud requires some modification of the traditional procedure of collecting and processing data in SIEM. Using specialized mediations primary data collection allows receiving comparable quality of monitoring of information security between local and clouding SIEM.
Keywords: SIEM; cloud; cloud service; monitoring of information security; virtualization
AUTOMATED INFORMATION SYSTEM FOR TELECOMMUNICATION NETWORK COMPLEX MONITORING
Abstract: The development of an information system for monitoring the status of a star topology corporate network is considered. Base requirements of the system are specified. The system uses the SMNP (Simple Network Management Protocol) and NetFlow protocols. The system software platform is developed using open standards and technologies. It consists of a set of specialized computer modules integrated with the Zabbix system. The modules provide comprehensive analysis of the network status data under a single user interface. A raw and processed data archiving system is described that provides for maximum processing speed in both operational observations and retrospective data analysis. An example of using the developed program tools is given based on the Regional Computer Network of FEB RAS.
Keywords: corporate telecommunication network; information system; network monitoring; SNMP; NetFlow; Zabbix; protocol; database management
SYSTEMATIZATION OF KNOWLEDGE ABOUT PROGRAMMABLE TASKS
Abstract: The article describes basics of the methodology for systematization of symbolic models of programmable tasks intended for development of systems of knowledge about tasks. This methodology is based on the results achieved in development and research of systems of computer-aided software design. The TSM-complex (Task S-Modeling) for description of models of arbitrary objects in human-machine environment (s-environment) is used for formalized representation of tasks. The tasks are represented as constructive objects (s-tasks) having certain types of relations and rules of design. S-task specification includes formulation, systems of mandatory and adjusting rules for solving, algorithms, sets of programs, and test cases. Descriptions of program applications include information about operating systems, hardware requirements, etc.
Keywords: s-modeling; task constructive object; s-task graph; system of knowledge about tasks
USING HASH FUNCTION FOR INCREASING SPEED OF WORK OF THE SOFTWARE FOR MORPHOLOGICAL ANALYSIS OF RUSSIAN TEXTS
Abstract: The paper considers the problem of increasing efficiency of morphological analysis of Russian texts. The software system for morphological analysis is described, including the set of morphological characteristics and the algorithms of work. The paper mentions the software systems solving the problem of log^-semantic analysis of natural language texts in which the software system for morphological analysis found application. Features of the system are discussed from the point of view of occupied memory and work speed. The way of storage of morpholexical information using hash functions is suggested which provides high speed of access. The difficulties arising during realization of such approach are discussed and possible solutions are considered. The paper describes the structure of information arrays of the new version and the search algorithms realized in it. The paper also describes a subsystem for putting in and updating morphological information. Specific parameters of the new realization of the software system for morphological analysis and information on speed of work acceleration in comparison with the previous version are given. The paper discusses opportunities of development of the new version of the software system for morphological analysis and of transferring the suggested approach to other components of the linguistic processor.
Keywords: morphological analysis; hash function; linguistic processor; log^- semantic analysis of natural language texts
ON LOGISTICS OF MOBILE ELECTRONIC TEXTBOOKS IMPLEMENTATION AND USE
Abstract: Taking into consideration the current situation of supply of broadband access in the schools in Russia, based on reviews in international and national publications regarding introduction of electronic textbooks, the authors identify a number of issues inherent to this process, inhibiting its successful implemen-tation and needing a proper resolution. The authors introduce the concept of ideal availability of an electronic textbook, based on which the authors suggest a number of ways of distribution of electronic textbooks. The authors introduce the notion of lifecycle of an electronic textbook, which helps to identify the pro-cesses of modernization and of creation of new textbooks. The authors also clarify the meaning of the notion of mobility of an electronic textbook. As a result, the authors managed to coin a prototype of an electronic textbook, which, when realized, allows minimizing its dependence on availability of broadband access. Therefore, this solution differs from its analogues both in Russia and globally.
Keywords: electronic textbooks; logistics; life cycle
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