Institute of Electron Technology
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Estimation of Network Disordering Eff ects by In-depth Analysis of the Resequencing Bu ffer Contents in Steady-state, Journal of Telecommunications and Information Technology, 2016, nr 1
Get PDFThe paper is devoted to the analytic analysis of resequencing issue, which is common in packet networks, using queueing-theoretic approach. The authors propose the mathematical model, which describes the simplest setting of packet resequencing, but which allows one to make the first step in the in-depth-analysis of the queues dynamics in the resequencing buffer. Specifically consideration is given to N-server queueing system (N > 3) with single infinite capacity buffer and resequencing, which may serve as a model of packet reordering in packet networks. Customers arrive at the system according to Poisson flow, occupy one place in the buffer and receive service from one of the servers, which is exponentially distributed with the same parameter. The order of customers upon arrival has to be preserved upon departure. Customers, which violated the order are kept in resequencing buffer which also has infinite capacity. It is shown that the resequencing buffer can be considered as consisting of n, 1 ≤ n ≤ N −1, interconnected queues, depending on the number of busy servers, with i-th queue containing customers, which have to wait for i service completions before they can leave the system. Recursive algorithm for computation of the joint stationary distribution of the number of customers in the buffer and servers, and each queue in resequencing buffer are being obtained. Numerical examples, which show the dynamics of the characteristics of the queues in resequencing buffer are given
Veri fication of Staff Pro ficiency in the Calibration Laboratory on Voltage, Frequency, Resistance and Capacity Measurements , Journal of Telecommunications and Information Technology, 2016, nr 4
Get PDFThe Laboratory of Electrical, Electronic and Optoelectronic Metrology is accredited by the Polish Center of Accreditation for nearly two decades. Over time, the requirements of proficiency verification are growing continuously. In order to satisfy higher and higher of reliability demands the most promising staff proficiency verification estimators were examined for voltage, frequency, resistance and capacity measurements. The article presents measurement systems used for verification, analysis of results or simulations, and shows conclusion for selecting the best solution
Properties of the Multiservice Erlang's Ideal Gradings, Journal of Telecommunications and Information Technology, 2016, nr 1
Get PDFThe design and optimization process of modern telecommunications networks is supported by a range of appropriate analytical models. A number of these models are based on the Erlang’s Ideal Grading (EIG) model, which is a particular case of non-full-availability groups. A possibility of the application of the EIG model results from the fact that telecommunications systems show properties and features distinctive to non-full-availability systems. No detailed studies that would decisively help determine appropriate conditions for the application of the EIG model for modeling of other non-full-availability groups, that would be models corresponding to real telecommunications systems, have been performed. Therefore, this article attempts to find an answer to the following question: what are the prerequisite conditions for the application of the EIG model and when the model can be reliably used
Telekomunikacja i Techniki Informacyjne, 2016, nr 1-2
Get PDFW artykule przedstawiono analizę realizacji projektów w ramach działań POIG, RPW i RPO poprzez pryzmat rozmieszczenia liczby i środków finansowych (wartości ogólnej oraz kwoty dofinansowania UE), zarówno na terenie całego kraju, regionów, jak i poszczególnych województw w latach 2012–2015. Podjęto próbę oceny, czy i w jakim stopniu, postęp w realizacji projektów i zaangażowane środki finansowe wpłynęły już na poprawę wybranych wskaźników charakteryzujących rozwój społeczeństwa informacyjnego oraz, czy zmiana liczby podmiotów gospodarczych (głównie z sektora mikro-, małych i średnich przedsiębiorstw) realizujących projekty w ramach kategorii interwencji 10–15 miała wpływ na zmiany poziomu bezrobocia w analizowanym okresie. Artykuł stanowi również uzupełnienie informacji przedstawionych w artykułach dotyczących narzędzi wspierających realizację Agendy 2020, które powstały w Instytucie Łączności w ramach kończącego się projektu „System Informacyjny o Infrastrukturze Szerokopasmowej i portal Polska Szerokopasmowa” (SIPS)
Comparison of Selected Fair-optimization Methods for Flow Maximization between Given Pairs of Nodes in Telecommunications Network, Journal of Telecommunications and Information Technology, 2016, nr 3
Get PDFDimensioning of telecommunications networks requires the allocation of the ows (bandwidth) to given trac demands for the source-destination pairs of nodes. Unit ow allocated to the given demand is associated with revenue that may vary for di erent demands. Problem the decision-making basic algorithms to maximize the total revenue may lead to the solutions that are unacceptable, due to "starvation" or "locking" of some demand paths less attractive with respect to the total revenue. Therefore, the fair optimization approaches must be applied. In this paper, two fair optimization methods are analyzed: the method of ordered weighted average (OWA) and the reference point method (RPM). The study assumes that ows can be bifurcated thus realized in multiple path schemes. To implement optimization model the AMPL was used with general-purpose linear programming solvers. As an example of the data, the Polish backbone network was used
Forecasting Stock Price using Wavelet Neural Network Optimized by Directed Arti ficial Bee Colony Algorithm, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFStock prediction with data mining techniques is one of the most important issues in finance. This field has attracted great scientific interest and has become a crucial research area to provide a more precise prediction process. This study proposes an integrated approach where Haar wavelet transform and Artificial Neural Network optimized by Directed Artificial Bee Colony algorithm are combined for the stock price prediction. The proposed approach was tested on the historical price data collected from Yahoo Finance with different companies. Furthermore, the prediction result was found satisfactorily enough as a guide for traders and investors in making qualitative decisions
Radio Photonic Systems for Measurement of Instantaneous Radio Frequency with Amplitude-phase Modulation of Optical Carrier, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFIn this article questions related to the development instantaneous radio frequency measurement system based on application in them original ways of the amplitude-phase modulation transformation of single-frequency optical carrier by a radio signal in symmetric two-frequency and measuring “frequency-amplitude” transformation in fiber Bragg grating with special profile are considered. Such systems have broad prospects for use in telecommunications, military systems and for environmental monitoring
Curved-Pentagonal Planar Monopole Antenna for UHF Television Broadcast Receiving Antenna, Journal of Telecommunications and Information Technology, 2016, nr 3
Get PDFA planar monopole antenna is an aerial, which the radiating element is perpendicular to the ground plane. It has five equal curvy sides and works at Ultra High Frequency (UHF) band of terrestrial broadcast 478–806 MHz. The curvy sides are made of five equal trimmed ellipses and separated 72o each ellipse to another, form pentagonal shape. Optimizations are obviously necessary to gain the antenna performance at the desired frequency range. The dimensions to optimize this antenna performance are the length of the sides, the offset of curvature, the antenna height from the ground plane, and the ground plane size. Optimization process is done by simulating the proposed antenna with calculated designs using Computer Simulation Technology (CST) Studio Suite 2015 software. The optimized antenna design then fabricated with a 75 W coaxial line fed, measured, and results: Voltage Standing Wave Ratio (VSWR) range of 1.05–1.28, antenna gain at 600 MHz is 15.33 dBi, elliptical polarized, and omnidirectional. With these features, this antenna should satisfy the requirements of UHF television broadcasting
DS-UWB and TH-UWB Energy Consumption Comparison, Journal of Telecommunications and Information Technology, 2016, nr 1
Get PDFThe energy consumption of the wireless communication systems is starting to be unaffordable. One way to improve the power consumption is the optimization of the communication techniques used by the communication networks and devices. In order to develop an energy efficient UWB multi-user communication system, the choice of modulation and multi access technique is important. This paper compares two Ultra-wideband multi-user techniques, i.e. the DS-UWB and the TH-UWB in the case of the Nakagami-m fading channel. For the DS-UWB technique, the orthogonal (T-OVSF, ZCD) and non-orthogonal (Kasami) codes are used. For TH-UWB, authors consider different modulations (PPM, PSM, PAM). This comparison allows choosing the best solution in terms of energy consumption, data rate and communication range. Two different studies are realized to find the most efficient technique to use. In the first study, the same number of users for the different type of codes (data rate values) is chosen and the total energy consumption for several distances and path-loss coefficient is computed. In the second one, the multiusers effects (same data rate) for various values of distances and path-loss are evaluated
Hybrid Models for the OWA Optimization, Journal of Telecommunications and Information Technology, 2016, nr 4
Get PDFWhen dealing with multicriteria problems, the aggregation of multiple outcomes plays an essential role in finding a solution, as it reflects the decision-maker's preferencerelation. The Ordered Weighted Averaging (OWA) operator provides a exible preference model that generalizes many objective functions. It also ensures the impartiality and allow to obtain equitable solutions, which is vital when the criteria represent evaluations of independent individuals. These features make the OWA operator very useful in many fields, one of which is location analysis. However, in general the OWA aggregation makes the problem nonlinear and hinder its computational complexity. Therefore, problems with the OWA operator need to be devised in an efficient way. The paper introduces new general formulations for OWA optimization and proposes for them some simple valid inequalities to improve efficiency. A hybrid structure of proposed models makes the number of binary variables problem type dependent and may reduce it signicantly. Computational results show that for certain problem types, some of which are very useful in practical applications, the hybrid models perform much better than previous general models from literature