Institute of Electron Technology
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2189 research outputs found
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Subcarrier Gain Based Power Allocation in Multicarrier Systems, Journal of Telecommunications and Information Technology, 2014, nr 1
Get PDFThe Orthogonal Frequency Division Multiplexing (OFDM) transmission is the optimum version of the multicarrier transmission scheme, which has the capability to achieve high data rate. The key issue of OFDMsystem is the allocation of bits and power over a number of subcarriers. In this paper, a new power allocation algorithm based on subcarrier gain is proposed to maximize the bit rate. For OFDM systems, the Subcarrier Gain Based Power Allocation (SGPA) algorithm is addressed and compared with the standard Greedy Power Allocation (GPA). The authors demonstrate by analysis and simulation that the proposed algorithm reduces the computational complexity and achieves a near optimal performance in maximizing the bit rate over a number of subcarrier
Quality of Variable Bitrate HD Video Transmission in New Generation Access Network, Journal of Telecommunications and Information Technology, 2014, nr 1
Get PDFArticle presents influence of multiplying variable bitrate high definition (HD) video streams in an access network link on Quality of Service (QoS). The aim of a conducted study is to define key parameters influencing Quality of Experience (QoE). Numerous simulations were performed and indicators like packet loss, delay, jitter, frame loss and bandwidth utilization were observed. Moreover, two independent algorithms were used to indicate QoE values of video streams. These are SwissQual VQuadHD and Telchemy VQMon applications which provided credible full reference and no reference algorithms, respectively. In the article evaluation of accuracy of no reference algorithm is performed. In future work it is planned to build analytic model of VBR video transmission and to undertake more thorough research of transmitting multiplied HD video streams in an access network using various QoS policies and optimizing size of buffer
An Agent-Based Collaborative Platform for the Optimized Trading of Renewable Energy within a Community, Journal of Telecommunications and Information Technology, 2014, nr 4
Get PDFCities are increasingly recognized for their ability to play a catalytic role in addressing climate and energy challenges using technologically innovative approaches. Since energy used in urban areas accounts for about 40% of total EU energy consumption, a change of direction towards renewable energy is necessary in order to alleviate the usage of carbonized electricity and also to save money. A combination of IT and telecommunication technologies is necessary to enable the energy and resources saving. ICT based solutions can be used to enable energy and money saving not only for a single building, but for the whole community of a neighborhood. In this paper a model for the energy cost minimization of a neighborhood together with an agent-based interaction model that reproduces the proposed formal representation is presented. Furthermore the authors present a prototype implementation of this model and first experimental tests
Ubiquity of Client Access in Heterogeneous Access Environment, Journal of Telecommunications and Information Technology, 2014, nr 3
Get PDFWith popularization of mobile computing and diverse offer of mobile devices providing functionality comparable to personal computers, the necessity of providing network access for such users cannot be disputed. The requirement is further reinforced by emergence of general purpose mobile operating systems which provide their full functionality only with network connectivity available and popular XaaS (Everything as a Service) approach. In this situation and combined with the fact that most Internet-based services are able to function efficiently even in best effort environment, requirement of ubiquity of network access becomes one of the most important elements of today’s computing environment. This paper presents a general overview of the the vast group of mechanisms and technologies utilized in modern attempts to efficiently provide ubiquity on network access in heterogeneous environment of today’s access systems. It starts with division of users interested in ubiquitous network access into broad groups of common interest, complete with their basic requirements and access characteristics, followed by a survey of both already popular and new wireless technologies suitable to provide such access. Then a general discussion of most important challenges which must be addressed while attempting to fulfill the above goal is provided, addressing topics such as handover control and mobility management
FTTH Network Optimization, Journal of Telecommunications and Information Technology, 2014, nr 4
Get PDFFiber To The Home (FTTH) is the most ambitious among optical technologies applied in the access segment of telecommunications networks. The main issues of deploying FTTH are the device price and the installation cost. Whilst the costs of optical devices are gradually decreasing, the cost of optical cable installation remains challenging. In this paper, the problem of optimization that has practical application for FTTH networks is presented. Because the problem is Non-deterministic polynomial-time hard (NP-hard), an approximation algorithm to solve it is proposed. The author has developed the algorithm in a C# program in order to analyze its performance. The analysis confirms that the algorithm gains near-optimal results with acceptable time consumption. Therefore, the algorithm to be applied in a network design tool for FTTH network planning is proposed
Comparative Study of Supervised Learning Methods for Malware Analysis, Journal of Telecommunications and Information Technology, 2014, nr 4
Get PDFMalware is a software designed to disrupt or even damage computer system or do other unwanted actions. Nowadays, malware is a common threat of the World Wide Web. Anti-malware protection and intrusion detection can be significantly supported by a comprehensive and extensive analysis of data on the Web. The aim of such analysis is a classification of the collected data into two sets, i.e., normal and malicious data. In this paper the authors investigate the use of three supervised learning methods for data mining to support the malware detection. The results of applications of Support Vector Machine, Naive Bayes and k-Nearest Neighbors techniques to classification of the data taken from devices located in many units, organizations and monitoring systems serviced by CERT Poland are described. The performance of all methods is compared and discussed. The results of performed experiments show that the supervised learning algorithms method can be successfully used to computer data analysis, and can support computer emergency response teams in threats detection
Transmit Diversity in the Downlink for the TETRA-TEDS System, Journal of Telecommunications and Information Technology, 2014, nr 1
Get PDFAbstract—In the paper a proposal for the improvement of performance for the TETRA Enhanced Data System (TEDS) employing transmit diversity based on two antennas in the downlink is described. The key idea of the considerations relies on using the spacerequency coding algorithm. The proposal described required some relatively simple changes to the existing TEDS’s Single Input Single Output (SISO) interface but the original number of payload and signaling symbols in the normal downlink burst is preserved. The simulation results obtained indicate a significant improvement in performance. The Eb/No parameter could be reduced from 5 to 8 dB with respect to Frame Error Rate (FER), compared to a single antenna transmission for the same FER = 10−3
Robust Audio Watermarks in Frequency Domain, Journal of Telecommunications and Information Technology, 2014, nr 2
Get PDFIn this paper an audio watermarking technique is presented, using log-spectrum, dirty paper codes and LDPC for watermark embedding. This technique may be used as a digital communication channel, transmitting data at about 40 b/s. It may be also applied for hiding a digital signature, e.g., for copyright protection purposes. Robustness of the watermarks against audio signal compression, resampling and transmitting through an acoustic channel is tested. In this paper an audio watermarking technique ispresented, using log-spectrum, dirty paper codes and LDPCfor watermark embedding. This technique may be used asa digital communication channel, transmitting data at about40 b/s. It may be also applied for hiding a digital signature,e.g., for copyright protection purposes. Robustness of the watermarks against audio signal compression, resampling andtransmitting through an acoustic channel is tested