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Ochrona odgromowa obiektów budowlanych i ich wyposażenia. Telekomunikacja i Techniki Informacyjne, 2013, nr 1-2
Get PDFCelem artykułu jest zwrócenie uwagi na specyficzne zagadnienia związane z ochroną obiektów budowlanych i ich wyposażenia przed oddziaływaniem wyładowań piorunowych. Poruszono też kwestie związane z normalizacją w ochronie odgromowej, istniejącym chaosem prawnym, nieodpowiednią reakcją urzędów państwowych, brakiem profesjonalizmu oraz ignorancją instalatorów i inspektorów nadzoru. Omówiono także zagadnienia związane z wrażliwością obiektów i wyposażenia na wyładowania piorunowe, wybiórczością piorunów przez zwody oraz bezpiecznym odprowadzaniem prądu wyładowania do ziemi
Assessing Coastal Sustainability: A Bayesian Approach for Modeling and Estimating a Global Index for Measuring Risk, Journal of Telecommunications and Information Technology, 2013, nr 4
Get PDFIntegrated Coastal Zone Management is an emerging research area. The aim is to provide a global view of different and heterogeneous aspects interacting in a geographical area. Decision Support Systems, integrating Computational Intelligence methods, can be successfully used to estimate useful anthropic and environmental indexes. Bayesian Networks have been widely used in the environmental science domain. In this paper a Bayesian model for estimating the Sustainable Coastal Index is presented. The designed Bayesian Network consists of 17 nodes, hierarchically organized in 4 layers. The first layer is initialized with the season and the physiographic region information. In the second layer, the first-order indexes, depending on raw data, of physiographic regions are computed. The third layer estimates the second-order indexes of the analyzed physiographic regions. In the fourth layer, the global Sustainable Coastal Index is inferred. Processed data refers to 13 physiographic regions in the Province of Trapani, western Sicily, Italy. Gathered data describes the environmental information, the agricultural, fisheries, and economical behaviors of the local population and land. The Bayesian Network was trained and tested using a real dataset acquired between 2000 and 2006. The developed system presents interesting results
Quasi-Offline Fair Scheduling in Third Generation Wireless Data Networks, Journal of Telecommunications and Information Technology, 2013, nr 3
Get PDFIn 3G wireless data networks, network operators would like to balance system throughput while serving users fairly. This is achieved through the use of fair scheduling. However, this approach provides non-Pareto optimal bandwidth allocation when considering a network as a whole. In this paper an optimal offline algorithm that is based on the decomposition result for a double stochastic matrix by Birkhoff and von Neumann is proposed. A utility max-min fairness is suggested for the derivation of a double stochastic matrix. Using a numerical experiment, new approach improves the fairness objective and is close to the optimal solution
Cooperative Games with Incomplete Information for Secondary Base Stations in Cognitive Radio Networks, Journal of Telecommunications and Information Technology, 2013, nr 3
Get PDFCognitive radio (CR) technology is considered to be an effective solution for enhancing overall spectrum efficiency. Using CR technology fully involves the providing of incentives to Primary Radio Networks (PRNs) and revenue to the service provider so that Secondary Base Stations (SBSs) may utilize PRN spectrum bands accordingly. In this paper, a cooperative games with incomplete information for SBSs in a CR network is presented. Each SBS can cooperate with neighboring SBSs in order to improve its view of the spectrum. Moreover, proposed game-theory models assume that the devices have incomplete information about their components, meaning that some players do not completely know the structure of the game. Using the proposed algorithm, each SBS can leave or join the coalition while maximizing its overall utility. The simulation results illustrate that the proposed algorithm allows us to reduce the average payoff per SBS up to 140% relative to a CR network without cooperation among SBSs
Analysis of the System with Vacations under Poissonian Input Stream and Constant Service Times, Journal of Telecommunications and Information Technology, 2013, nr 3
Get PDFIn the paper approximate formulas for the mean waiting times and the buffer dimensioning in the system with vacations fed by the stream of Poissonian type with constant service times is shown. Furthermore, in the considered system the time intervals of the availability/not-availability of the service are constant and are run alternately according to the assumed cycle. More precisely, presented approach begin with derivation of the mean waiting times and, on the basis of this, the required buffer size for guaranteeing the losses less than predefined value is estimated. The accuracy of the presented analytical formulas is on a satisfactory level. The formulas were used for the System IIP dimensioning
Minimizing Cost of Network Upgrade for Overlay Multicast – Heuristic Approach, Journal of Telecommunications and Information Technology, 2013, nr 3
Get PDFA rapid increase of the Internet users and traffic at the rate of 31% in years 2011–2016 contributes to emerging of new approaches to the content distribution. Among other approaches, the overlay multicasting seems to be one of the most interesting concepts according to relatively low deployment costs and large scalability. In this paper, the authors formulate a new incremental multicast overlay design problem. In particular, authors assumed that the overlay network is to be upgraded due to an increase of the number of participating users and the need to improve the streaming quality. However, the existing multicast tree structure is assumed to remain fixed. The goal was to minimize the cost of the upgrade, represented in euro/month. To achieve it, for each peer participating in the transmission, a link type offered by one of the ISPs was selected and overlay trees were constructed, rooted at the source of the content. The authors also present a new heuristic algorithm to efficiently solve this problem. According to experiments, the biggest factor influencing the upgrade cost and determining possible streaming quality values that the system can be upgraded to is the initial tree structure
Enhancement of Speech Communication Technology Performance Using Adaptive-Control Factor Based Spectral Subtraction Method, Journal of Telecommunications and Information Technology, 2013, nr 2
Get PDFThis paper presents speech enhancement technique based on Spectral Subtraction (SS) method. SS is a renowned noise reduction technique that works on the principle that noise spectrum estimate over the entire speech spectrum can be subtracted from the noisy signal. On the contrary, most of the noise encountered in the real-world conditions is majorly colored. Unlike Additive White Gaussian Noise (AWGN), colored noise does not affect the speech signal uniformly over the entire spectrum. To mitigate effects of colored noise on the processed signal, we propose a Multi-Band Spectral Subtraction (MBSS) method using novel Adaptive-Control Factor (ACF). The spectrum is divided into frequency sub bands based on a nonlinear multi-band frame and various signal-to-noise ratios (SNRs) are considered. The proposed scheme results in better system performance with quality signal and unlike the basic SS method. It mitigates the effects of anomaly known as “musical” tones artifacts in the processed signal thatresult in residual noise and speech distortion. The computational complexity involved is minimal. Furthermore, simulation results show that the proposed algorithm removes more colored noise without removing the relatively low amplitude speech signal over the entire speech spectrum. Subjective listening tests, with clean speech signals and different noise levels, show discernable performance of our proposed method when compared with the conventional SS approach
Connecting for Surgery: The Belgian Use Case on the Legal Aspects of the Digital Operating Room, Journal of Telecommunications and Information Technology, 2013, nr 1
Get PDFTelecommunications technology is making its way into operating rooms by new developments in e-health. However, conflicts arise with existing legal principles regarding data protection. This paper deals with key elements of the interactions between data protection and evolution in e-health. The scope will be the digital operating room, where different health services and activities converge through networked technology, raising a number of privacy-related issues. For instance, the patient’s health records and tools for recording surgical procedures could be integrated within the same platform, potentially leading to sensitive personal data linkage. Also the possible duration and reason of storage of surgical recordings, is a matter that remains largely unresolved in current practice. First, this paper will analyze the data exchanges of the digital operating room. As these will include personal patient data, it must be assessed whether and how the European framework on data protection can apply. Second, the regulatory regime of the manufacturers of the devices of the digital operating room will be analyzed. Can the current legal framework relating to e-health provide for suitable regulation for such devices? Drawing from experience gained in research projects, this paper aims to provide practical answers to often theoretical questions
ID Layer for Internet of Things Based on Name-Oriented Networking, Journal of Telecommunications and Information Technology, 2013, nr 2
Get PDFObject and service identification is considered as one of the main challenges in the field of Internet of Things (IoT), which can be solved by the introduction of the so called ID (IDentifier) layer. The objective of this layer is to expose IoT objects and services offered by them, to users. Common approach for ID layer is to create it in overlay manner, on the top of existing network. This paper presents a novel architecture of the ID layer, which is characterized by embedding ID layer functionality into the network plane. Moreover, this approach takes advantage of the Name-Oriented Networking (NON) paradigm. To gain easy access to the IoT objects and services, as well as native support for multicast service, human readable ID-based unified addressing with hierarchical structure was exploited. Additionally, in-network caching of forwarded IoT data, inherited from the NON, helps to reduce total network load and supports applications during collaboration with energy-constrained sensors. Such sensors may enter sleep mode to save energy and then the network nodes can serve requests for sensing data, arrived from applications, by using data stored in nodes’ cache. The paper shows the concept of NON-based ID layer and describes functional architecture of network node paying attention on modules and mechanisms related with ID layer functionality. Primary ID layer processes, i.e., object/service registration, resolution and data forwarding are explained in detail. Moreover, the ID-aware network node was implemented on Linux-based platform and tested to check its forwarding characteristics. The tests showed the performance of the of ID network node in data plane operations, which are the more sensitive for scalability issues
Recurrent Method for Blocking Probability Calculation in Switching Networks with Overflow Links, Journal of Telecommunications and Information Technology, 2013, nr 1
Get PDFThis article presents a new recurrent method for modelling multi-service switching networks with overflow links. In the proposed method, the blocking probability for a given stage of the switching network is determined on the basis of the characteristics of the preceding stage. A particular attention is given to a possibility of a considerable reduction of the internal blocking probability of the switching network that would result from an application of additional overflow links between neighbouring switches of the first stage of the network. The results of the analytical modelling of selected multi-service switching networks with overflow links in the first stage are compared with the results of the simulation experiments. The study confirms the accuracy of all the adopted theoretical assumptions in the proposed analytical model of the multi-service switching network