Institute of Electron Technology
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Nowelizacja pakietu regulacyjnego dla rynku komunikacji elektronicznej Unii Europejskiej - ramy prawne, dostęp i zezwolenia. Biuletyn Informacyjny Instytutu Łączności, 2010, nr 1
Get PDFW numerze 1/2010 "Biuletynu Informacyjnego Instytutu Łączności" omówiono podstawowe propozycje zmian w dyrektywach ramowej, o dostępie i o zezwoleniach, które były przedmiotem dyskusji w trakcie nowelizacji pakietu regulacyjnego 2002. Przypomniano pierwotne propozycje Komisji, a następnie przedstawiono stanowisko poszczególnych organów Unii Europejskiej, ze szczególnym uwzględnieniem Parlamentu Europejskiego, w procesie legislacyjnym. Wskazano propozycje dotyczące ochrony inwestycji i konkurencji infrastrukturalnej, problematyki współdziałania organów unijnych i regulatorów krajowych w procedurach regulacyjnych, nowej polityki w zarządzaniu częstotliwościami radiowymi oraz ochrony użytkowników. Na zakończenie rozważań scharakteryzowano zatwierdzone zmiany w analizowanych dyrektywach
Iris Recognition System Based on Zak-Gabor Wavelet Packets, Journal of Telecommunications and Information Technology, 2010, nr 4
Get PDFThe paper proposes a new iris coding method based on Zak-Gabor wavelet packet transform. The essential component of the iris recognition methodology design is an effective adaptation of the transformation parameters that makes the coding sensitive to the frequencies characterizing ones eye. We thus propose to calculate the between-to-within class ratio of weakly correlated Zak-Gabor transformation coefficients allowing for selection the frequencies the most suitable for iris recognition. The Zak-Gabor-based coding is non-reversible, i.e., it is impossible to reconstruct the original iris image given the iris template. Additionally, the inference about the iris image properties from the Zak-Gabor-based code is limited, providing a possibility to embed the biometric replay attack prevention methodology into the coding. We present the final prototype system design, including the hardware, and evaluate its performance using the database of 720 iris images
A Framework for Evaluationof Communication Bandwidth Market Models, Journal of Telecommunications and Information Technology, 2010, nr 2
Get PDFThe article presents a method of analysis of market-based models for resource allocation in communication networks. It consists of several stages: classification of a market model, generation of input data, data adaptation to a tested model, test calculations and, finally, presentation and interpretation of results. A set of general criteria to assess various models has been proposed. Tests are run using dedicated computer applications, data is stored in open XML-based format originated in the multicommodity market model. Network topologies are derived from the SNDlib library
Routing Misbehavior Detection in MANETs Using 2ACK, Journal of Telecommunications and Information Technology, 2010, nr 4
Get PDFThis paper proposes routing misbehavior detection in MANETs using 2ACK scheme. Routing protocols for MANETs are designed based on the assumption that all participating nodes are fully cooperative. However, due to the open structure and scarcely available battery-based energy, node misbehavior may exist. In the existing system, there is a possibility that when a sender chooses an intermediate link to send some message to a destination, the intermediate link may pose problems such as, the intermediate node may not forward the packets to destination, it may take very long time to send packets or it may modify the contents of the packet. In MANETs, as there is no retransmission of packets once it is sent, care must be taken not to loose packets. We have analyzed and evaluated a technique, termed 2ACK scheme to detect and mitigate the effect of such routing misbehavior in MANETs environment. It is based on a simple 2-hop acknowledgment packet that is sent back by the receiver of the next-hop link. 2ACK transmission takes place for only a fraction of data packets, but not for all. Such a selective acknowledgment is intended to reduce the additional routing overhead caused by the 2ACK scheme. Our contribution in this paper is that, we have embedded some security aspects with 2ACK to check confidentiality of the message by verifying the original hash code with the hash code generated at the destination. If 2ACK is not received within the wait time or the hash code of the message is changed then the node to next hop link of sender is declared as the misbehaving link. We simulated the routing misbehavior detection using 2ACK scheme to test the operation scheme in terms of performance parameters
Large-Signal RF Modeling with the EKV3 MOSFET Model, Journal of Telecommunications and Information Technology, 2010, nr 1
Get PDFThis paper presents a validation of the EKV3 MOSFET model under load-pull conditions with high input power at 5.8 GHz, as well as S-parameter measurements with low input power up to 20 GHz. The EKV3 model is able to represent coherently the large- and small-signal RF characteristics in advanced 90 nm CMOS technology. Multifinger devices with nominal drawn gate length of 70 nm are used
Ochrona środowiska przed elektromagnetycznym promieniowaniem niejonizującym. Telekomunikacja i Techniki Informacyjne, 2010,nr 3-4
Get PDFOpisano oddziaływanie pola elektromagnetycznego pochodzącego z różnych źródeł na organizm człowieka i skalę zagrożeń dla zdrowia. Przeanalizowano zasady określania wartości dopuszczalnych pola w Polsce i na świecie dla ogółu społeczeństwa i osób pracujących w otoczeniu źródeł pola. Przedstawiono działalność Instytutu Łączności w dziedzinie kompatybilności elektromagnetycznej i pomiarów pola dla celów BHP i ochrony środowiska
Jakość usługi głosowej w sieciach Telekomunikacyjnych. Telekomunikacja i Techniki Informacyjne, 2010, nr 1-2
Get PDFDokonano przeglądu najważniejszych obiektywnych metod porównawczych, stosowanych przy ocenie jakości mowy transmitowanej we współczesnych sieciach telekomunikacyjnych. Wyszczególniono i zbadano wpływ czynników degradujących jakość mowy transmitowanej w wybranych sieciach oraz przedstawiono ogólny proces testowania jakości mowy transmitowanej. Zaproponowano optymalne i akceptowane przez użytkowników wartości wskaźnika jakości mowy
Speech Segmentation Algorithm Based on an Analysis of the Normalized Power Spectral Density, Journal of Telecommunications and Information Technology, 2010, nr 4
Get PDFThis article demonstrates a new approach to speaker independent phoneme detection. The core of the algorithm is to measure the distance between normalized power spectral densities in adjacent, short-time segments and verify it based on velocity of changes of values of short-time signal energy analysis. The results of experiment analysis indicate that proposed algorithm allows revealing a phoneme structure of pronounced speech with high probability. The advantages of this algorithm are absence of any prior information on a signal or model of phonemes and speakers that allows the algorithm to be speaker independent and have a low computation complexity
Face Tracking and Recognition with the Use of Particle-Filtered Local Features, Journal of Telecommunications and Information Technology, 2010, nr 4
Get PDFA consistent particle filtering-based framework for the purpose of parallel face tracking and recognition from video sequences is proposed. A novel approach to defining randomized, particle filtering-driven local face features for the purpose of recognition is proposed. The potential of cumulating classification decisions based on the proposed feature set definition is evaluated. By applying cumulation mechanisms to the classification results determined from single frames and with the use of particle-filtered features, good recognition rates are obtained at the minimal computational cost. The proposed framework can operate in real-time on a typical modern PC. Additionally, the application of cumulation mechanisms makes the framework resistant to brief visual distortions, such as occlusions, head rotations or face expressions. A high performance is also obtained on low resolution images (video frames). Since the framework is based on the particle filtering principle, it is easily tunable to various application requirements (security level, hardware constraints)