Institute of Electron Technology
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LDAOR - Location and Direction Aware Opportunistic Routing in Vehicular Ad hoc Networks, Journal of Telecommunications and Information Technology, 2016, nr 1
Get PDFRouting in Vehicular Ad hoc Networks (VANETs) has found significant attention because of its unique features such as lack of energy constraints and high-speed vehicles applications. Besides, since these networks are highly dynamic, design process of routing algorithms suitable for an urban environment is extremely challenging. Appropriate algorithms could be opportunistic routing (OR) where traffic transmission is performed using the store-carry-forward mechanism. An efficient OR mechanism, called Location and Direction Aware Opportunistic Routing (LDAOR), is proposed in this paper. It is based on the best neighbor node selection by using vehicles positions, vehicles directions, and prioritization of messages from buffers, based on contact histories and positions of neighbor nodes to destination. In LDAOR, when multiple nodes make contact with a carrier node, the closest neighbor node to destination is selected as the best forwarder. However, when only one node makes contact with the carrier node, the message is delivered to it if it moves toward the destination. Using the ONE simulator, the obtained performance evaluation results show that the LDAOR operates better than conventional OR algorithms. The LDAOR not only increases delivery rate, but also reduces network overhead, traffic loss, and number of aborted messages
Quantifying the Suitability of Reference Signals for the Video Streaming Analysis for IPTV, Journal of Telecommunications and Information Technology, 2016, nr 1
Get PDFIP networks are indispensable nowadays and they are some of the most efficient platforms. The constantly growing number of users and new services in these networks – the largest being the Internet – require a satisfactory quality of service from any application they use. So, determining the QoS in real-time services is particularly important. This work shows how to quantify the suitability of reference signals for analyzing the quality of video streaming in IPTV. The assessment relies on two different algorithms: PEVQ and VQuad-HD. Three different reference signals – two real ones and an artificial one – are used in this study, and a numerical measurement system is used, which simulates mean network impairments. These measurements provide valuable information for determining the QoS of actual IPTV services in practice
System SIRS jako unikalne źródło wiedzy na temat projektów budowy regionalnych sieci szerokopasmowych, Telekomunikacja i Techniki Informacyjne, 2016, nr 1-2
Get PDFW artykule zaprezentowano użytkowe aspekty Systemu Informatycznego o Regionalnych Sieciach Szerokopasmowych (SIRS). W opisie funkcjonalności systemu skoncentrowano się na tych, które są najważniejsze i najczęściej wykorzystywane przez administrację publiczną. Podkreślono unikalny charakter niektórych danych – m.in. interaktywnych map dotyczących dokumentacji powykonawczej, czy wykorzystanych narzędzi z grupy Business Intelligence weryfikujących poprawność danych. Całość opatrzono wnioskami z analizy danych zbieranych i przechowywanych w systemie
Link Quality and Energy Aware Geographical Routing in MANETs using Fuzzy Logics, Journal of Telecommunications and Information Technology, 2016, nr 3
Get PDFIn literature, varieties of topology and geographical routing protocols have been proposed for routing in the MANETs. It is widely accepted that the geographical routings are a superior decision than topological routings. Majority of geographical routing protocols assume an ideal network model and choose the route that contains minimum number of hops. However, in reality, nodes have limited battery power and wireless links are additionally unreliable, so they may highly affect the routing procedure. Thus, for reliable data transmission, condition of the network such as link quality and residual energy must be considered. This paper aims to propose a novel multi-metric geographical routing protocol that considers both links-quality and energy metric along with progress metric to choose the next optimal node. The progress is determined by utilizing greedy as well as compass routing rather than pure greedy routing schemes. To combine these metrics, fuzzy logics are used to get the optimal result. Further, the protocol deals with “hole” problem and proposes a technique to overcome it. Simulations show that the proposed scheme performs better in terms of the packet delivery ratio, throughput and residual energy than other existing protocols
Graph-based Forensic Analysis of Web Honeypot, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFHoneypot still plays an important role in network security, especially in analyzing attack type and defining attacker patterns. Previous research has mainly focused on detecting attack pattern while categorization of type has not yet been-comprehensively discussed. Nowadays, the web application is the most common and popular way for users to gather information, but it also invites attackers to assault the system. Therefore, deployment of a web honeypot is important and its forensic analysis is urgently required. In this paper, authors propose attack type analysis from web honeypot log for forensic purposes. Every log is represented as a vertex in a graph. Then a custom agglomerative clustering to categorize attack type based on PHP-IDS rules is deployed. A visualization of large graphs is also provided since the actual logs contain tens of thousands of rows of records. The experimental results show that the proposed model can help forensic investigators examine a web honeypot log more precisely
Call Blocking Probabilities of Multirate Elastic and Adaptive Traffic under the Threshold and Bandwidth Reservation Policies, Journal of Telecommunications and Information Technology, 2016, nr 1
Get PDFThis paper proposes multirate teletraffic loss models of a link that accommodates different service-classes of elastic and adaptive calls. Calls follow a Poisson process, can tolerate bandwidth compression and have an exponentially distributed service time. When bandwidth compression occurs, the service time of new and in-service elastic calls increases. Adaptive calls do not alter their service time. All calls compete for the available link bandwidth under the combination of the Threshold (TH) and the Bandwidth Reservation (BR) policies. The TH policy can provide different QoS among service-classes by limiting the number of calls of a service-class up to a predefined threshold, which can be different for each service-class. The BR policy reserves part of the available link bandwidth to benefit calls of high bandwidth requirements. The analysis of the proposed models is based on approximate but recursive formulas, whereby authors determine call blocking probabilities and link utilization. The accuracy of the proposed formulas is verified through simulation and found to be very satisfactory
An Efficient Early Iteration Termination for Turbo Decoder, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFTurbo code finds wide applications in mobile communication, deep space communication, satellite communication and short-range communication despite its high computational complexity and iterative nature. Realizing capacity approaching turbo code is a great achievement in the field of communication systems due to its efficient error correction capability. The high computational complexity associated with the iterative process of decoding turbo code consumes large power, introducing decoding delay, and reducing the throughput. Hence, efficient iteration control techniques are required to make the turbo code more power efficient. In this paper, a simple and efficient early iteration termination technique is introduced based on absolute value of the mean of extrinsic information at the component decoders of turbo code. The simulation results presented clearly show that the proposed method is capable of reducing the average number of iterations while maintaining performance close to that of fixed iteration termination. The significant reduction in iteration achieved by the method reduces decoding delay and complexity while maintaining Bit Error Rate performance close to standard fixed iteration turbo decoder
Energy-saving Algorithms for the Control of Backbone Networks: A Survey, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFThe rapid growth of energy demand by wired IP networks can be mitigated on hardware and software levels. While upgrading to more efficient transmission media still brings biggest savings, we take a look here at power-saving algorithms that combine the capability of setting networking equipment in arbitrary energy states which, combined with profound knowledge of the network traffic matrix, leads to considerable complex optimization problem formulations. Alternatively, lightweighted heuristic approaches are presented, built on much simpler network model but still capable to perform energy-efficient traffic engineering
Preconditioned Conjugate Gradient Method for Solution of Large Finite Element Problems on CPU and GPU, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFIn this article the preconditioned conjugate gradient (PCG) method, realized on GPU and intended to solution of large finite element problems of structural mechanics, is considered. The mathematical formulation of problem results in solution of linear equation sets with sparse symmetrical positive definite matrices. The authors use incomplete Cholesky factorization by value approach, based on technique of sparse matrices, for creation of efficient preconditioning, which ensures a stable convergence for weakly conditioned problems mentioned above. The research focuses on realization of PCG solver on GPU with using of CUBLAS and CUSPARSE libraries. Taking into account a restricted amount of GPU core memory, the efficiency and reliability of GPU PCG solver are checked and these factors are compared with data obtained with using of CPU version of this solver, working on large amount of RAM. The real-life large problems, taken from SCAD Soft collection, are considered for such a comparison
Similarity Index based Link Prediction Algorithms in Social Networks: A Survey, Journal of Telecommunications and Information Technology, 2016, nr 2
Get PDFSocial networking sites have gained much popularity in the recent years. With millions of people connected virtually generate loads of data to be analyzed to infer meaningful associations among links. Link prediction algorithm is one such problem, wherein existing nodes, links and their attributes are analyzed to predict the possibility of potential links, which are likely to happen over a period of time. In this survey, the local structure based link prediction algorithms existing in literature with their features and also the possibility of future research directions is reported and discussed. This survey serves as a starting point for beginners interested in understanding link prediction or similarity index algorithms in general and local structure based link prediction algorithms in particular