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A Study of Wireless Sensor Networks to Comprehend their Relevance to Different Applications, Journal of Telecommunications and Information Technology, 2020, nr 2
Full text linkWireless sensor networks (WSNs) have experienced enormous growth, both in terms of the technology used and their practical applications. In order to understand the features of WSNs that make the solution suitable for a specific purpose, one needs to be aware of the theoretical concepts behind and technological aspects of WSNs. In this paper, the significance of WSNs is illustrated, with a particular emphasis placed on their demands and on understanding researchrelated problems. A review of the literature available is presented as well. Detailed discussions concerning sensor node architecture, different types of sensors used and their relevance for various types of WSNs is presented, highlighting the need to achieve application-specific requirements without degrading service quality. Multipath and cluster-based routing protocols are compared in order to analyze QoS requirements they are capable of satisfying, and their suitability for different application areas is reviewed. This survey highlights the performance of different routing protocols, therefore providing guidelines enabling each of the routing techniques to be used, in an efficient manner, with factors such as specific network structure, protocol operation and routing path construction taken into consideration in order to achieve better performanc
A New Parameterized Model for Determining Quality of Online Video Service Using Modern H.265/HEVC and VP9 Codecs, Journal of Telecommunications and Information Technology, 2020, nr 4
Full text linkThis paper describes a new measurement method (VS model) for determining the quality of online video services relying on modern H.265/HEVC and VP9 codecs. The said method has been developed on the basis of VQuad-HD curves (according to ITU-T J.341). This model does not refer to signal analysis, but protocol analysis instead. The parameters used are: type of video codec, encoding rate, transport technique, packet loss and burst size. The method may be implemented quickly and easily, which is one of the great advantages when using this method to measure Qo
Electromagnetic Scattering of Inhomogeneous Plane Wave by Ensemble of Cylinders, Journal of Telecommunications and Information Technology, 2020, nr 3
Full text linkThe interaction between an ensemble of cylinders and an inhomogeneous plane wave is introduced and is determined, in the present paper, through a rigorous theoretical approach. Scattered electromagnetic field generated by an indefinite number of infinite circular cylinders is analyzed by the application of the generalized vector cylinder harmonics (VCH) expansion. The exact mathematical model relied upon to represent this scenario considers the so-called complex-angle formalism reaching a superposition of vectorial cylindrical-harmonics and Foldy-Lax Multiple scattering equations (FLMSE) to account for the multiscattering process between the cylinders. The method was validated by comparing the numerical results obtained with the use of the finite element method and a homemade Matlab cod
An Expert System for Automatic Classification of Sound Signals, Journal of Telecommunications and Information Technology, 2020, nr 2
Full text linkIn this paper, we present the results of research focusing on methods for recognition/classification of audio signals. We consider the results of the research project to serve as a basis for the main module of a hybrid expert system currently under development. In our earlier studies, we conducted research on the effectiveness of three classifiers: fuzzy classifier, neural classifier and WEKA system for reference data. In this project, a particular emphasis was placed on fine-tuning the fuzzy classifier model and on identifying neural classifier applications, taking into account new neural networks that we have not studied so far in connection with sounds classification method
First and Second Order Characteristics of a Wireless Three-hop Relay Channel with the Presence of Rayleigh Fading, Journal of Telecommunications and Information Technology, 2020, nr 2
Full text linkIn this paper, a wireless three-hop relay communication system operating in a Rayleigh multipath fading environment is analyzed. The output signal from such a system is a product of signal envelopes from all sections, meaning that it is actually a product of three random variables (RVs) with Rayleigh distribution. We considered here the first-order characteristics: probability density function (PDF), cumulative distribution function and outage probability (OP). Then, the moments and amount of fading (AoF) were derived in the closed forms. The second order characteristics we present include the following: level crossing rate (LCR) and average fade duration (AFD). A few graphs are given to show the impact of the specific parameters of the wireless three-hop relay syste
V2X Communications for Platooning: Sensor Inaccuracy Aspects, Journal of Telecommunications and Information Technology, 2020, nr 2
Full text linkPlatooning is a future approach to autonomous driving in which vehicle-to-vehicle and vehicle-to-infrastructure communications play an important role. Tests performed in the past showed that a significant reduction in fuel consumption is possible when cars are traveling in a dense platoon formation. To increase the level of their awareness of the surrounding objects and to maintain a very short distance to the preceding vehicle, highly reliable on-board sensors are required. This paper discusses the impact of sensor inaccuracy on the performance and behavior of and autonomous vehicle platoon that makes use of wireless communications supported by context information from various databases and map
A Comparison Study of DASH Technique by Video Streaming over IP with the Use of RTP and HTTP Protocols, Journal of Telecommunications and Information Technology, 2020, nr 1
Full text linkToday’s Internet knows no bounds. New applications are marketed every single day. Many of them incorporate video sequences. These must be transported over the Internet quickly (often in real time). However, the Internet has not been designed for live communications and, regrettably, this may become apparent all too quickly. Countermeasures are required in the form of new, efficient transport techniques facilitating online video services. MPEG-DASH is one of such modern techniques. But how good is this new technique really? This paper delves into the matter. The paper contains an analysis of the impact that the new technology exerts on the quality of video streaming over IP networks. It also describes a new numerical tool – QoSCalc (DASH-HTTP) which has been used to analyze MPEG-DASH under different use scenarios. The results are presented graphically and their interpretation is provide
Transmission of Disaster Warnings via Control Channels in Cellular Networks, Journal of Telecommunications and Information Technology, 2020, nr 4
Full text linkAccording to United Nations reports, natural disasters caused, worldwide, approximately 100,000 deaths and affected 175 million people each year between 2004 and 2013. To reduce those numbers, countries around the globe have made specific arrangements enabling them to warn the population about imminent disasters, in order to evacuate the area in due time. But providing such warnings in areas where no Internet access is available poses a great challenge. In this paper, we proposed a method to transmit early warning messages via UMTS cellular networks, while relying on spare extensions of control channels (FACH). The results obtained are validate based on their comparison with theoretical considerations and are also benchmarked against the 3GPP standard. The results show that messages may be sent faster than with the use of the 3GPP standar
Application of Graph Theory Algorithms in Non-disjoint Functional Decomposition of Specific Boolean Functions, Journal of Telecommunications and Information Technology, 2020, nr 3
Full text linkFunctional decomposition is a technique that allows to minimize Boolean functions that cannot be optimally minimized using other methods, such as variable reduction and linear decomposition. A heuristic method for finding nondisjoint decomposition has been proposed lately. In this paper, we examine how the usage of different graph theory techniques affects the computation time and the quality of the solution obtained. In total, six different approaches were analyzed. The results presented herein prove the advantages of the proposed approaches, showing that results obtained for standard benchmark M-out-of-20 functions are better than those presented in previous publication. Results obtained for randomly generated functions prove that time complexity and scalability are significantly better when using the heuristic graph coloring algorithm. However, quality of the solution is worse, in genera
Fuzzy-based Description of Computational Complexity of Central Nervous Systems, Journal of Telecommunications and Information Technology, 2020, nr 3
Full text linkComputational intelligence algorithms are currently capable of dealing with simple cognitive processes, but still remain inefficient compared with the human brain’s ability to learn from few exemplars or to analyze problems that have not been defined in an explicit manner. Generalization and decision-making processes typically require an uncertainty model that is applied to the decision options while relying on the probability approach. Thus, models of such cognitive functions usually interact with reinforcement-based learning to simplify complex problems. Decision-makers are needed to choose from the decision options that are available, in order to ensure that the decision-makers’ choices are rational. They maximize the subjective overall utility expected, given by the outcomes in different states and weighted with subjective beliefs about the occurrence of those states. Beliefs are captured by probabilities and new information is incorporated using the Bayes’ law. Fuzzy-based models described in this paper propose a different – they may serve as a point of departure for a family of novel methods enabling more effective and neurobiologically reliable brain simulation that is based on fuzzy logic techniques and that turns out to be useful in both basic and applied sciences. The approach presented provides a valuable insight into understanding the aforementioned processes, doing that in a descriptive, fuzzy-based manner, without presenting a complex analysi