Narcis Behlilovic

Analysis of Effect of Some Parameters of Symmetrical-Copper-Twisted-Pair on Quality of ADSL Service

This paper is analyzing how some symmetrical-cooper-twisted-pair parameters take effect to of ADSL services. The treated parameters are insulation resistance, hop resistance and attenuation (on several significant frequencies). As the parameter of quality of service the bit-rate (both up-stream and down-stream bit-rate) is used. The testing transmission line is twisted pair placed in low-band telecommunication cable, with variable length (up to 8000 meters), and with 0.4 mm conductor diameter. We treated two types of low-band telecommunications cables-cable with paper-based insulation and lead-shield (approximately 25 years old), and cable with polyethylene-based insulation and aluminium-shield (2.5 years old). Basic theory of electrical loops is given at begin, measurements results and conclusion follow after that

Comparation of QoS parameters of received IPTV signals, using different compression algorithms for streaming Live or Stored AV Materials

Importance of digitalization of AV (audio/video) signals, produced in TV studios, has been recognized long time ago, and in many countries, TV studios abandoned old analog transmission, leaving place for digital signal transmission. In Bosnia and Herzegovina, TV studios are still producing and broadcasting analog PAL signal, but according to recommendation, they should switch to DVB before 2012. Because of the actuality of this problem, the main idea of this paper was to make appropriate hardware and software solution for digitalization of PAL signal, acquired on the output of analog cameras or stored on tapes in studios, and its transmission over IP based network, together with application on client side. Using developed solutions on server and client sides, different types of compression and container formats are tested, in order to recommend TV stations the solution for producing digital AV signals with the best quality for end users, in future DVB network.

An example of improvement of access network triple-play ability by local loop shortening

This paper presents an example of improvement of access network ability to provide triple-play service with satisfied QoE. The improvement is made by copper twisted pair local loop shortening. The local loop shortening is done on real buried copper access network in the rural area. A comparison of parameters before and after loop shortening is shown. Some parameters of the physical layer defined in Recommendation ITU-T G.997.1, such as code violation, forward error correction code and the number of seconds with corrected errors on the observed loops are used for comparison. Of course, the quantities like up/down bit rate, line attenuation, SNR margin, etc. are also analysed. All of experiments are done by observing triple-play services in real ADSL2+ environment.

CryptoStego — A novel approach for creating cryptographic keys and messages

This paper proposes a cryptographic key establishment method based on set of images shared by sender and receiver. The method is simple, fast and secure. We call it CryptoStego. Possible key sizes are virtually limitless. Proposed method is implemented in C programming language. The implementation is compared with (A)RC4 stream cipher, by comparing CPU time and memory occupation by both algorithms. The results of comparison are presented. Intel VTune Amplifier XE 2011 was used as measuring tool.

Symbol Error Probability Analysis of L-Branch Maximal-Ratio Combiner for Generalized eta-mu Fading

Maximal-Ratio Combiner (MRC) performances in fading channels have been of interest for a long time, which can be seen by a number of papers concerning this topic. Most of these papers treat Rayleigh, Nakagami-m, Hoyt, Rice or Weibull fading. This paper treats symbol error probability (SEP) performances of MRC in presence of generalized eta-mu fading. In this paper, we will present eta-mu fading model, and expressions for SEP of the L-branch MRC output. SEP will be treated for a broad class of modulation types and for non-coherent type of detection. SEP performances of the MRC will be presented via Monte Carlo simulations and theoretical expressions.

Research of symmetrical copper based twisted pair near active ADSL service parameters properties

This paper researches changing of some basic parameters of symmetrical copper based twisted pair which is near the other twisted pair where active ADSL service exists. Analyzed parameters are: attenuation, signal to noise ratio, wideband noise and characteristic impedance. Analyzed subject is one pair in cable whose capacity is 100 x 2 x 0.4, with foamed polyethylene insulation and laminated polyethylene sheath. Existing ADSL service is sent through the different pairs in the observe cable and changes of the treated pair parameters are measured depending on the distance of the existing ADSL service from it. Obtained results are compared among themselves and with the parameters which are obtained in absence of ADSL service.

Euclidean Distance-Based QoS Metric for Dynamic MAP Selection in HMIPv6 Network

This paper proposes metrics based on QoS preferences of MNs, and QoS abilities of MAPs, in order to perform a simulative evaluation of the Hierarchical Mobile IPv6 (HMIPv6) network implementation with QoS-aware dynamic MAP selection. The chosen metric meets the desired level of QoS, while retaining MAP load balance, while the DiffServ mechanism ensured the required QoS for HMIPv6 network implementation with QoS-aware dynamic MAP selection.

Analysis of impact of adjacent local loops on some significant DSL transceivers parameters

This paper analyses the behaviour of the adjacent ten DSL local loops in the copper based twisted pair cable with foamed polyethylene insulation. Some parameters of the physical layer defined in Recommendation ITU-T G.997.1, such as code violation, forward error correction code and the number of seconds with corrected errors on the observed DSL lines are analysed. Also, this paper analyses the values of some electrical parameters on those same DSL lines. Based on the values of observed parameters, possibility of simultaneous operation of adjacent DSL lines, even that they carry triple-play services is shown.

Numerical model for calculation of parameters of cathodic protection system with galvanic anodes

This paper presents the use of coupled BEM/FEM method by the numeric calculations of protection current/potential distribution when the cathodic protection system with galvanic anodes is applied. Cathodic protection (CP) system is very efficient system for protection of underground metal object from corrosion. The most important phase by installing the CP system is to optimally and correctly defines the distribution of the protection current. There are many correlation related factors that influence the dimensioning of CP elements and the time of their design. The distribution of protection current/potential in systems of cathodic protection is governed by the Laplace equation, with the usage of corresponding predefined boundary conditions. Field data are obtained during the installation of the system and periodical field measurements during the exploitation of cathodic protection system with galvanic anodes. In this paper, acquired field data are compared to the values that were obtained using numerical calculations. Deviations between these data are negligible. Values of protection current/potential are most influenced by values of soil resistivity between anode and cathode surface.

Comparing randomness on various video and Audio Media File types

This paper analyses randomness in various video and audio media file types, like: Joint Photographic Experts Group (JPEG), Waveform Audio File Format (WAV), Flash video (FLV), high-quality, free and open video format for the web (WEBM) and MPEG-1 Audio Layer 3 (MP3). Analysis is done by executing different statistical test. Statistical tests are usually used for testing different both True Random Number Generators (TRNG) and Pseudo-Random Number Generators (PRNG), but we use them in this paper to analyse various media file types instead of TRNGs and PRNGs output results. Proposed methods for analysing are implemented in C programming language, by using one part of ENT (pseudo random number sequence test program) and making additional scripts for faster processing. Comparison of randomness is done by comparing different file types and accompanying results of statistical tests with each other. The results of comparison are presented.