DSpace Collection: Volume 2 Number 2
http://hdl.handle.net/10525/19
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Towards Useful Overall Network Teletraffic Definitions
http://hdl.handle.net/10525/162
Title: Towards Useful Overall Network Teletraffic Definitions<br/><br/>Authors: Poryazov, Stoyan<br/><br/>Abstract: A detailed conceptual and a corresponding analytical traffic models of an overall (virtual) circuitswitching telecommunication system are used. The models are relatively close to real-life communicationsystems with homogeneous terminals. In addition to Normalized and Pie-Models Ensue Model and Denial Trafficconcept are proposed, as a parts of a technique for presentation and analysis of overall network traffic modelsfunctional structure; The ITU-T definitions for: fully routed, successful and effective attempts, and effective trafficare re-formulated. Definitions for fully routed traffic and successful traffic are proposed, because they are absentin the ITU-T recommendations; A definition of demand traffic (absent in ITU-T Recommendations) is proposed.For each definition are appointed: 1) the correspondent part of the conceptual model graphical presentation; 2)analytical equations, valid for mean values, in a stationary state. This allows real network traffic considered to beclassified more precisely and shortly. The proposed definitions are applicable for every telecommunicationsystem.Study of Queueing Behaviour in IP Buffers
http://hdl.handle.net/10525/164
Title: Study of Queueing Behaviour in IP Buffers<br/><br/>Authors: Mirtchev, Seferin<br/><br/>Abstract: It is unquestioned that the importance of IP network will further increase and that it will serve as aplatform for more and more services, requiring different types and degrees of service quality. Modernarchitectures and protocols are being standardized, which aims at guaranteeing the quality of service delivered tousers. In this paper, we investigate the queueing behaviour found in IP output buffers. This queueing increasesbecause multiple streams of packets with different length are being multiplexed together. We develop balanceequations for the state of the system, from which we derive packet loss and delay results. To analyze these typesof behaviour, we study the discrete-time version of the “classical” queue model M/M/1/k called Geo/Gx/1/k, whereGx denotes a different packet length distribution defined on a range between a minimum and maximum value.VoIP Traffic Shaping Analyses in Metropolitan Area Networks
http://hdl.handle.net/10525/154
Title: VoIP Traffic Shaping Analyses in Metropolitan Area Networks<br/><br/>Authors: Goleva, Rossitza; Goleva, Mariya; Atamian, Dimitar; Nikolov, Tashko; Golev, Kostadin<br/><br/>Abstract: This paper represents VoIP shaping analyses in devices that apply the three Quality of Servicetechniques – IntServ, DiffServ and RSVP. The results show queue management and packet stream shapingbased on simulation of the three mostly demanded services – VoIP, LAN emulation and transaction exchange.Special attention is paid to the VoIP as the most demanding service for real time communication.Traffic Offered Behaviour Regarding Target QOS Parameters in Network Dimensioning
http://hdl.handle.net/10525/163
Title: Traffic Offered Behaviour Regarding Target QOS Parameters in Network Dimensioning<br/><br/>Authors: Saranova, Emiliya<br/><br/>Abstract: We consider a model of overall telecommunication network with virtual circuits switching, in stationarystate, with Poisson input flow, repeated calls, limited number of homogeneous terminals and 8 types of losses.One of the main problems of network dimensioning/redimensioning is estimation of traffic offered in networkbecause it reflects on finding of necessary number of circuit switching lines on the basis of the consideration ofdetailed users manners and target Quality of Service (QoS). In this paper we investigate the behaviour of thetraffic offered in a network regarding QoS variables: “probability of blocked switching” and “probability of findingB-terminals busy”. Numerical dependencies are shown graphically. A network dimensioning task (NDT) isformulated, solvability of the NDT and the necessary conditions for analytical solution are researched as well.International Journal "Information Technologies and Knowledge" Vol.2 / 2008174The received results make the network dimensioning/redimensioning, based on QoS requirements easily, due toclearer understanding of important variables behaviour.The described approach is applicable directly for every (virtual) circuit switching telecommunication system e.g.GSM, PSTN, ISDN and BISDN. For packet - switching networks, at various layers, proposed approach may beused as a comparison basis and when they work in circuit switching mode (e.g. VoIP).Intelligent Car Parking Locator Service
http://hdl.handle.net/10525/161
Title: Intelligent Car Parking Locator Service<br/><br/>Authors: Ganchev, Ivan; O’Droma, Mairtin; Meere, Damien<br/><br/>Abstract: This paper presents an InfoStation-based multi-agent system facilitating a Car Parking Locator serviceprovision within a University Campus. The system network architecture is outlined, illustrating its functioningduring the service provision. A detailed description of the Car Parking Locator service is given and the systementities’ interaction is described. System implementation approaches are also considered.Formalization of Interaction Events in Multi-agent Systems
http://hdl.handle.net/10525/155
Title: Formalization of Interaction Events in Multi-agent Systems<br/><br/>Authors: Cheremisinov, Dmitry; Cheremisinova, Liudmila<br/><br/>Abstract: The problem of the description of interaction between spatially divided agents in the form of dialoguesis explored. The concept of processes synchronization is analyzed to formalize the specification of interaction atthe level of events constituting the processes. The approach to formalization of the description of conditions ofsynchronization when both the independent behavior and the communications of agents can be presented at alogic level is offered. It is shown, that the collective behavior of agents can be specified by the synthetic temporallogic that unites linear and branching time temporal logics.Modeling Optical Response of Thin Films: Choice of the Refractive Index Dispersion Law
http://hdl.handle.net/10525/152
Title: Modeling Optical Response of Thin Films: Choice of the Refractive Index Dispersion Law<br/><br/>Authors: Sharlandjiev, Peter; Stoilov, Georgi<br/><br/>Abstract: Determination of the so-called optical constants (complex refractive index N, which is usually a functionof the wavelength, and physical thickness D) of thin films from experimental data is a typical inverse non-linearproblem. It is still a challenge to the scientific community because of the complexity of the problem and its basicand technological significance in optics. Usually, solutions are looked for models with 3-10 parameters. Bestestimates of these parameters are obtained by minimization procedures. Herein, we discuss the choice oforthogonal polynomials for the dispersion law of the thin film refractive index. We show the advantage of theiruse, compared to the Selmeier, Lorentz or Cauchy models.Mathematical Model and Simulation of a Pneumatic Apparatus for In-Drilling Alignment of an Inertial Navigation Unit during Horizontal Well Drilling
http://hdl.handle.net/10525/160
Title: Mathematical Model and Simulation of a Pneumatic Apparatus for In-Drilling Alignment of an Inertial Navigation Unit during Horizontal Well Drilling<br/><br/>Authors: Djurkov, Alexander; Cloutier, Justin; Mintchev, Martin P.<br/><br/>Abstract: Conventional methods in horizontal drilling processes incorporate magnetic surveying techniques fordetermining the position and orientation of the bottom-hole assembly (BHA). Such means result in an increasedweight of the drilling assembly, higher cost due to the use of non-magnetic collars necessary for the shielding ofthe magnetometers, and significant errors in the position of the drilling bit. A fiber-optic gyroscope (FOG) basedinertial navigation system (INS) has been proposed as an alternative to magnetometer -based downholesurveying. The utilizing of a tactical-grade FOG based surveying system in the harsh downhole environment hasbeen shown to be theoretically feasible, yielding a significant BHA position error reduction (less than 100m over a2-h experiment). To limit the growing errors of the INS, an in-drilling alignment (IDA) method for the INS has beenproposed. This article aims at describing a simple, pneumatics-based design of the IDA apparatus and itsimplementation downhole. A mathematical model of the setup is developed and tested with Bloodshed Dev-C++.The simulations demonstrate a simple, low cost and feasible IDA apparatus.Smart Portable Fluorometer for Express-Diagnostics of Photosynthesis: Principles of Operation and Results of Experimental Researches
http://hdl.handle.net/10525/158
Title: Smart Portable Fluorometer for Express-Diagnostics of Photosynthesis: Principles of Operation and Results of Experimental Researches<br/><br/>Authors: Romanov, Volodymyr; Sherer, Volodimyr; Galelyuka, Igor; Sarakhan, Yevgeniya; Skrypnyk, Oleksandra<br/><br/>Abstract: In the Institute of Cybernetics of National Academy of Sciences of Ukraine the smart portablefluorometer for express-diagnostics of photosynthesis was designed. The device allows easy to estimate the levelof influence of natural environment and pollutions to alive plants. The device is based on real time processing ofthe curve of chlorophyll fluorescent induction. The principles of operation and results of experimental researchesof device are described in the article.General Regression Neuro–Fuzzy Network for Identification of Nonstationary Plants
http://hdl.handle.net/10525/165
Title: General Regression Neuro–Fuzzy Network for Identification of Nonstationary Plants<br/><br/>Authors: Bodyanskiy, Yevgeniy; Nataliya, Teslenko<br/><br/>Abstract: General Regression Neuro-Fuzzy Network, which combines the properties of conventional GeneralRegression Neural Network and Adaptive Network-based Fuzzy Inference System is proposed in this work. Thisnetwork relates to so-called “memory-based networks”, which is adjusted by one-pass learning algorithm.Advance of the Access Methods
http://hdl.handle.net/10525/156
Title: Advance of the Access Methods<br/><br/>Authors: Markov, Krassimir; Ivanova, Krassimira; Mitov, Ilia; Karastanev, Stefan<br/><br/>Abstract: The goal of this paper is to outline the advance of the access methods in the last ten years as well asto make review of all available in the accessible bibliography methods.Complex Protection System of Metadata-based Distributed Information Systems
http://hdl.handle.net/10525/159
Title: Complex Protection System of Metadata-based Distributed Information Systems<br/><br/>Authors: Kourilov, Denis; Lyadova, Lyudmila<br/><br/>Abstract: A description of architecture and approaches to the implementation of a protection system of metadatabasedadaptable information systems is suggested. Various protection means are examined. The systemdescribed is a multilevel complex based on a multiagent system combining IDS functional abilities with structureand logics protection means.ICT Security Management
http://hdl.handle.net/10525/153
Title: ICT Security Management<br/><br/>Authors: Schreurs, Jeanne; Moreau, Rachel<br/><br/>Abstract: Security becomes more and more important and companies are aware that it has become amanagement problem. It’s critical to know what are the critical resources and processes of the company and theirweaknesses. A security audit can be a handy solution. We have developed BEVA, a method to critically analysethe company and to uncover the weak spots in the security system. BEVA results in security scores for eachsecurity factor and also in a general security score. The goal is to increase the security score Ss to a postulatedlevel by focusing on the critical security factors, those with a low security score.Analysis of Information Security of Objects under Attacks and Processed by Methods of Compression
http://hdl.handle.net/10525/157
Title: Analysis of Information Security of Objects under Attacks and Processed by Methods of Compression<br/><br/>Authors: Polimirova-Nickolova, Dimitrina; Nickolov, Eugene<br/><br/>Abstract: In this paper a methodology for evaluation of information security of objects under attacks, processedby methods of compression, is represented. Two basic parameters for evaluation of information security ofobjects – TIME and SIZE – are chosen and the characteristics, which reflect on their evaluation, are analyzed andestimated. A co-efficient of information security of object is proposed as a mean of the coefficients of theparameter TIME and SIZE. From the simulation experiments which were carried out methods with the highestco-efficient of information security had been determined. Assessments and conclusions for future investigationsare proposed.