Institute of Electron Technology
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Enhancing Security of Advanced Metering Infrastructure by Introducing Threshold Attendance Protocol , Journal of Telecommunications and Information Technology, 2014, nr 2
Get PDFThe industry pushes towards Smart grid systems in order to resolve current limitations of the unidirectional legacy power grid infrastructure. By introducing Advanced Metering Infrastructure (AMI) as an integral part of the Smart grid solution, the utility company obtains an invaluable tool to optimize its network, lower the operational costs, and improve quality of service. Unfortunately, introducing two-way communication poses a security risk to the power grid infrastructure. In this paper the authors consider a Threshold Attendance Protocol (TAP) acting in a reverted security paradigm. Its main idea is to keep the network load at a predictable level at all times. To achieve that, TAP in AMI environment is embedded and the solution using real-life simulation parameters is validated
Możliwe scenariusze zmian i rozwoju rynku telewizyjnego w Polsce. Telekomunikacja i Techniki Informacyjne, 2014, nr 1-2
Get PDFArtykuł porusza istotną tematykę rozwoju ogólnodostępnych mediów elektronicznych w Polsce, szczególnie w kontekście dyskusji na temat tzw. drugiej dywidendy cyfrowej. Przedstawia aktualny stan rynku telewizyjnego w kontekście zmian wywołanych cyfryzacją telewizji naziemnej i dyskutuje możliwe scenariusze rozwoju tej części rynku w Polsce
Design of a Superconducting Antenna Integrated with a Diplexer for Radio-Astronomy Applications, Journal of Telecommunications and Information Technology, 2014, nr 3
Get PDFThis paper presents the design of a compact frontend diplexer for radio-astronomy applications based on a self complementary Bow-tie antenna, a 3 dB T-junction splitter and two pass-band fractal lters. The whole diplexer structure has been optimized by using an evolutionary algorithm. In particular the problem of the diplexer design is recast into an optimization one by dening a suitable cost function which is then minimized by mean of an evolutionary algorithm namely the Particle Swarm Optimization (PSO). An X band diplexer prototype was fabricated and assessed demonstrating a good agreement between numerical and experimental results
Normalized Gaussian Approach to Statistical Modeling of OFDM Signals, Journal of Telecommunications and Information Technology, 2014, nr 1
Get PDFThis article concerns modeling of statistical properties of OFDM signals with the help of “normalized Gaussian” model, proposed by Kotzer et al. In this paper there is provided an extended formulation of the model, supplemented by an expression for probability density, extending possible applications of the model in theoretical works. Numerical results for verification of the model are provided and a more accurate alternative is suggested
Review of Simulators for Wireless Mesh Networks, Journal of Telecommunications and Information Technology, 2014, nr 3
Get PDFThe research of computer networks construction of models that reect the current audited environment to carry out practical research is extremely difficult and often involves significant costs. Hence, the popularity of simulation tools that help developers to determine as early as at the stage of the simulation whether a given solution can be deployed in a real network. However, over time many different simulation tools have been developed, each with different characteristics, different uses, different strengths and weaknesses. It is the task of the researcher then to select, before starting the actual research, one of the available simulators in accordance with the needs and adopted criteria of evaluation. In the article the authors present issues related to the simulation tools and the main advantages of simulation as well as their drawbacks. To help researchers select an appropriate simulation environment, the authors present statistical information gathered during a literature survey of a number of research articles from the most popular publishers in which the selected simulators were used in initial system design
DVB-T Channels Measurements for the Deployment of Outdoor REM Databases, Journal of Telecommunications and Information Technology, 2014, nr 3
Get PDFIn this paper the analysis of the spectrum occupancy in the TV band is provided based on the outdoor measurements campaigns carried out in Poznań, Poland in 2013 and 2014. The goal of this work is to discuss the stability and other important features of the observed spectrum occupancy in the context of outdoor Radio Environment Maps database deployment. Reliable deployment of these databases seems to be one of the critical points in practical utilization of the TV White Spaces for cognitive purposes inside buildings and in densely populated cities. The results obtained for outdoor scenario are briefly compared with the previous measurements conducted indoors in Barcelona, Spain, and in Poznań, Poland
Design and Development of Miniature Dual Antenna GPS-GLONASS Receiver for Uninterrupted and Accurate Navigation, Journal of Telecommunications and Information Technology, 2014, nr 4
Get PDFGlobal Positioning System (GPS), Global Navigation Satellite System (GLONASS), and GPS-GLONASS receivers are commonly used for navigation. However, there are some applications where a single antenna interface to a GPS or GPS-GLONASS receiver will not suffice. For example, an airborne platform such as an Unmanned Aerial Vehicles (UAV) will need multiple antennae during maneuvering. Also, some applications will need redundancy of antenna connectivity to prevent loss of positioning if a link to satellite fails. The scope of this work is to design a dual antenna GPS-GLONASS navigation receiver and implement it in a very small form-factor to serve multiple needs such as: provide redundancy when a link fails, and provide uninterrupted navigation even under maneuvering, also provide improved performance by combining data from both signal paths. Both hardware and software architectures are analyzed before implementation. A set of objectives are identified for the receiver which will serve as the benchmarks against which the receiver will be validated. Both analysis and objectives are highlighted in this paper. The results from the tests conducted on such a dual antenna GPS-GLONASS receiver have given positive results on several counts that promise a wider target audience for such a solution
Regulacja bodźcowa w telekomunikacji. Telekomunikacja i Techniki Informacyjne, 2014, nr 1-2
Get PDFArtykuł stanowi zarys problematyki regulacji bazującej na wynikach, regulacji pułapem cenowym w kontekście transformowania sektora telekomunikacyjnego z tego opartego na podejściu monopolistycznym do podejścia opartego na konkurencji (deregulacji). Zaprezentowane treści obejmują cechy charakterystyczne regulacji bazującej na wynikach, regulacji pułapem cenowym, mechanizm tej regulacji, oraz rolę wiarygodności regulacyjnej w procesie konstrukcji planów regulacyjnych opartych na silnych bodźcach
Gradient-Based Algorithms in the Brachistochrone Problem Having a Black-Box Represented Mathematical Model , Journal of Telecommunications and Information Technology, 2014, nr 1
Get PDFTrajectory optimization problems with black-box represented objective functions are often solved with the use of some meta-heuristic algorithms. The aim of this paper is to show that gradient-based algorithms, when applied correctly, can be effective for such problems as well. One of the key aspects of successful application is choosing, in the search space, a basis appropriate for the problem. In an experiment to demonstrate this, three simple adaptations of gradient-based algorithms were executed in the forty-dimensional search space to solve the brachistochrone problem having a blackbox represented mathematical model. This experiment was repeated for two different bases spanning the search space. The best of the algorithms, despite its very basic implementation, needed only about 100 iterations to find very accurate solutions. 100 iterations means about 2000 objective functional evaluations (simulations). This corresponds to about 20 iterations of a typical evolutionary algorithm, e.g. ES(μ,l )
Comparative Study between Several Direction of Arrival Estimation Methods , Journal of Telecommunications and Information Technology, 2014, nr 1
Get PDFIn this paper a comparative study, restricted to one-dimensional stationary case, between several Direction of Arrival (DOA) estimation algorithms of narrowband signals is presented. The informative signals are corrupted by an Additive White Gaussian Noise (AWGN), to show the performance of each method by applying directly the algorithms without pre-processing techniques such as forward-backward averaging or spatial smoothing