Monthly Archives: November 2010

Dynamic Approach for Inter-cell Interference Control for LTE Networks

Vaska Georgieva, Pavlina Koleva, Vladimir Poulkov

Abstract: In this paper a dynamic approach to lCl mitigation is proposed by dividing the outage of
the cell into different zones. The approach is based on the model of Full Frequency Reuse system,
thus keeping the capacity of the system at its maximum. The major advantage of the method is the
aim for better utilization of the available frequency spectrum by allocating the most suitable
frequency resource to the user achieving better cell edge performance and improved throughput.
Simulations show that the effectiveness of the method depends on the traffic load of the system.
Even with traffic load of 80% the gain in signal-to-interference plus noise ratio is significant.

Keywords: LTE, Inter-cell Interference Control, Dynamic Frequency Reuse.

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Policy Based Resource Allocation in Wireless Networks Using a Cross-Layer Approach

Ivaylo Atanasov, Georgi Iliev, Vladimir Poulkov, Evelina Pencheva

Abstract: Policy-driven resource allocation provides for telecom operators great flexibility in
network resource management. In lP Multimedia Subsystem (IMS), policy and charging control
includes means for authorization and usage control of bearer resources intended for multimedia
traffic. The paper suggests a cross layer approach to resource allocation in wireless networks
which is based on lMS policy and charging control architecture. The approach bridges the quality of
service requirements of the application and physical layers. An extension of the protocol that is
used for policy and charging control is proposed without violating the existing protocol functionality.
The need for layer coordination is substantiated taking into account some existing methods for
throughput improvement and a new developed method for interference suppression. Delegating the
quality of service resource authorization in wireless networks to the IMS Iayer provides a number of
benefits such as session and service continuity.

Key words: cross layer design, multimedia service provisioning, wireless networks, resource
management, policies, throughput improvement

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Determination of the Geometric form of the Visible Faces and Objects in 3D Visual Scene

Maria Angelova

Abstract: The author proposes a system for a complete analysis of 3D visual scenes, which uses a
contour binary image of the scene with described segments and nodes as an input information An
important part of the analysis is the determination of the geometric form of the visible faces and
objects in the scene. The author is solving the problem by analysis of the structural-linguistic
descriptions derived for the visual scene. Appropriate heuristic classification rules are also defined.

Key words: closed contour, closing phrase, contour connected group of objects, 3D visual scene, visible object face

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Information Security of the e-Government Systems

Roumen Trifonov

Abstract: The paper makes an analysis of the information security statement of the information
systems in state administration regarding e-government development. View of the legal framework, e-governance and information security politics is done in this material. Pasportization of the information systems in state administration and implemented information security projects is presented. Conclusions and recommendations is made at the end of the paper.

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Designing and Building High Security Computer Networks

Georgi Naydenov, Petko Stoyanov

Abstract: In today’s networked era, as organizations increase their dependence on networks,
network security becomes more and more critical. Most networks do not have the proper degree of security. This article provides a comprehensive review of topics important to build secure network architectures. Security aspects of firewalls, router access lists and NAT, switch port security, VLANS and VPNs are analyzed. A brief comprehensive treatment of DMZs, intrusion detection and preventing systems (IDS/IPS) is presented. Finally. the article concludes recommending a general approach to acquire the proper degree of network security.

Keywords: Network Security Aspects, Information security

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OLAP Database Query Optimization

Daniela Gotseva, Veska Gancheva

Abstract: The investigations presented in this paper, are aimed to optimization of database that are used for storing data using OLAP cubes. The possibilities for optimal setting of SQL Server are presented. Some solutions for optimization of query to database are suggested.

Key words: database, database server, query, optimization, OLAP.

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Resource Discovery in Peer-to-Peer Network

Ognian Nakov, Plamenka Borovska,
Adelina Aleksieva-Petrova, Anastasios Profitis

Abstract: Peer-to-Peer is a wide and rapidly growing network model that a number of features
such as search, locate and provide different hardware resources for consumers. Multi-agent based systems are used in an increasing variety of applications, ranging from relatively small systems for personal assistance systems to industrial applications. This article provides an agent-based approach for resource discovery in peer-to-peer networks, effective resource planning through the implementation of matehieristical iterative algorithm with local search to move forward to generate the timetable. To develop agent-based applications is used JADE software in accordance with the FlPA specifications for interoperable intelligent multi-agent systems.

Key words: agent-based system, JADE, peer-to-peer, resource management, timetable.

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Spectral Analysis Based on Wavelet Transforms for Plastics Identification

Plamenka Borovska, Veska Gancheva, lvailo Georgiev, Orlin Ruev

Abstract: An approach for plastic identification using spectral analyses on the basis of wavelet transformation. A program system utilizing discrete wavelet transformation on the basis of Mallat algorithm is designed and implemented. The system use 3 basic functions – Haar, Daubechies, Coiflet, A number of experiments have been conducted and the conclusion is that the wavelet transformations are fast, reliable and with high accuracy. Best results are obtained using the wavelet basic function Haar.

Key words: wavelet transformation, plastic, identification, Coiflet, Daubechies, Haar.

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Resource Management in Dynamic Network Using Rerounting Tables

Plamenka Borovska, Ognian Nakov,
Adelina Aleksieva-Petrova, Petros Georgonikos

Abstract: Resource management is a complex process in a dynamic network which is an actual interest today. The main purpose of this paper is to improve performance in resource discovery in such type of network. The method of resource management is proposed based on mobile agents using rerouted tables. It allows a simultaneous request to different nodes to be implemented in parallel in the network.

Key words: agent, router, rerouting tables, resource management.

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Modeling and Tools for Computer Communication Networks

Plamenka Borovska, Halil Alkaf

Abstract: In this paper we present an overview of modern tolls for modeling and simulation of computer communication networks that are extremely important for scientific research, network design and scaling evaluation as well as for rapid network prototyping and education. A comparative analysis has been performed of methodologies for system evaluation in respect to networks. The concept and functional description of discrete event network simulators have been presented. The most important aspects of computer simulations as well as good popular practices for network simulation have been analyzed. The application aspects of the methodology for network performance research and evaluation on the basis of computer simulations are explored. A wide spectrum of contemporary network simulators has been presented.

Key words: discrete event simulation, network simulators, discrete event modeling and simulation tools.

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