+48 22 5128 100  

Szachowa 1,
04-894 Warszawa

Journal of Telecommunications and Information Technology (JTIT) - 3/2016

Krzysztof Borzycki
[ Bibtex Plain ]
Priya Mishra, Charu Gandhi and Buddha Singh
Link Quality and Energy Aware Geographical Routing in MANETs using Fuzzy Logics
In 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.
[ Bibtex Plain ]
Grzegorz Zalewski and Włodzimierz Ogryczak
Comparison of Selected Fair-optimization Methods for Flow Maximization between Given Pairs of Nodes in Telecommunications Network
Dimensioning 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.
[ Bibtex Plain ]
Paweł Białoń
A Practical Approach to Trac Engineering using an Unsplittable Multicommodity Flow Problem with QoS Constraints
The paper presents a practical approach to calculating intra-domain paths within a domain of a content-aware network (CAN) that uses source routing. This approach was used in the prototype CAN constructed as a part of the Future Internet Engineering project outcome. The calculated paths must satisfy demands for capacity (capacity for a single connection and for aggregate connections using the given path are considered distinctly) and for a number of path-additive measures like delay, loss ratio. We state a suitable variant of QoS-aware unsplittable multicommodity ow problem and present the solving algorithm. The algorithm answers to the needs of its immediate application in the constructed system: a quick return within a short and fairly predictable time, simplicity and modi ability, good behavior in the absence of a feasible solution (returning approximately-feasible solutions, showing how to modify demands to retain feasibility). On the other hand, a certain level of overdimensioning of the network is explored, unlike in a typical optimization algorithm. The algorithm is a mixture of: (i) shortest path techniques, (ii) simpli ed reference-level multicriteria techniques and parametric analysis applied to aggregate the QoS criteria (iii) penalty and mutation techniques to handle the common constraints. Numerical experiments assessing various aspects of the algorithm behavior are given.
[ Bibtex Plain ]
Mateusz Krzysztoń and Ewa Niewiadomska-Szynkiewicz
Heavy Gas Cloud Boundary Estimation and Tracking using Mobile Sensors
This paper addresses issues concerned with design and managing of monitoring systems comprised of mobile wireless sensing devices (MANETs). The authors focus on self-organizing, cooperative and coherent networks that maintain a continuous communication with a central operator and adopt to changes in an unknown environment to achieve a given goal. The attention is focused on the development of MANET for heavy gas clouds detection and its boundary estimating and tracking. Two strategies for constructing the MANET are described, in which sensors explore the region of interest to detect the gas cloud, create temporary network topology and finally, cover the cloud boundary, and track the moving cloud. The utility and efficiency of the proposed strategies has been justified through simulation experiments.
[ Bibtex Plain ]
Saleh Seyedzadeh, Majid Moghaddasi and Siti B. A. Anas
Variable-Weight Optical Code Division Multiple Access System using Different Detection Schemes
In this paper a Variable Weight OCDMA (VWOCDMA) system using KS code with Direct Decoding (DD), Complementary Subtraction (CS) and AND subtraction detections is proposed. System performance is analyzed using mathematical approximation and software simulation. In mathematical analysis, the effects of Phase-Induced Intensity Noise, shot noise and thermal noise are taken into account. Bit Error Rate of different users is plotted as a function of received optical power per chip with varying the bit rates and number of active users. It has been shown that for different bit rates and number of users, system using DD has better performance than the system applying CS and AND detection. Using DD scheme, the number of active users are 100 while this value is 27 and 25 in case of using CS and AND detection, respectively, when the received optical power per chip is –10 dBm.
[ Bibtex Plain ]
Janusz H. Klink, Maria J. Podolska and Tadeus Uhl
Concept for a Measurement Management System for Access Service to the Internet
This paper describes the problems associated with the provision of quality of service over an access connection to the Internet, i.e. the Internet Access Service (IAS). The paper has something of an overview character. Following a comprehensive introduction to the subject of “Changing Network Technologies” the paper focuses on the topic “Quality of IAS” in the light of regulatory directives of the European Parliament and the latest recommendations of ITU-T and ETSI. The focus will then shift to “Measurement Points and Measurement Scenarios for Determining QoS”. This topic will be described in detail and illustrated with several graphics. The final chapter has a pronounced scientific character and contains, among other things, a suggestion for a so-called Measurement Management System (MMS) to aid the design, execution and evaluation of efficient, automatic QoS measurements in networks.
[ Bibtex Plain ]
Andrzej Wilczyński, Agnieszka Jakóbik and Joanna Kołodziej
Stackelberg Security Games: Models, Applications and Computational Aspects
Stackelberg games are non-symmetric games where one player or specified group of players have the privilege position and make decision before the other players. Such games are used in telecommunication and computational systems for supporting administrative decisions. Recently Stackleberg games became useful also in the systems where security issues are the crucial decision criteria. In this paper authors briefly survey the most popular Stackelberg security game models and provide the analysis of the model properties illustrated in the realistic use cases.
[ Bibtex Plain ]
Paweł Kobojek and Khalid Saeed
Application of Recurrent Neural Networks for User Verification based on Keystroke Dynamics
Keystroke dynamics is one of the biometrics techniques that can be used for the verification of a human being. This work briefly introduces the history of biometrics and the state of the art in keystroke dynamics. Moreover, it presents an algorithm for human verification based on these data. In order to achieve that, authors’ training and test sets were prepared and a reference dataset was used. The described algorithm is a classifier based on recurrent neural networks (LSTMand GRU). High accuracy without false positive errors as well as high scalability in terms of user count were chosen as goals. Some attempts were made to mitigate natural problems of the algorithm (e.g. generating artificial data). Experiments were performed with different network architectures. Authors assumed that keystroke dynamics data have sequence nature, which influenced their choice of classifier. They have achieved satisfying results, especially when it comes to false positive free setting.
[ Bibtex Plain ]
Mateusz Trokielewicz and Ewelina Bartuzi
Cross-spectral Iris Recognition for Mobile Applications using High-quality Color Images
With the recent shift towards mobile computing, new challenges for biometric authentication appear on the horizon. This paper provides a comprehensive study of cross-spectral iris recognition in a scenario, in which high quality color images obtained with a mobile phone are used against enrollment images collected in typical, near-infrared setups. Grayscale conversion of the color images that employs selective RGB channel choice depending on the iris coloration is shown to improve the recognition accuracy for some combinations of eye colors and matching software, when compared to using the red channel only, with equal error rates driven down to as low as 2%. The authors are not aware of any other paper focusing on cross-spectral iris recognition is a scenario with near-infrared enrollment using a professional iris recognition setup and then a mobile-based veri cation employing color images.
[ Bibtex Plain ]
Michał Wroński
Faster Point Scalar Multiplication on Short Weierstrass Elliptic Curves over Fp using Twisted Hessian Curves over Fp2
This article shows how to use fast Fp2 arithmetic and twisted Hessian curves to obtain faster point scalar multiplication on elliptic curve ESW in short Weierstrass form over Fp. It is assumed that p and #ESW(Fp) are different large primes, #E(Fq) denotes number of points on curve E over field Fq and #Et SW (Fp) Fp), where Et is twist of E, is divisible by 3. For example this method is suitable for two NIST curves over Fp: NIST P-224 and NIST P-256. The presented solution may be much faster than classic approach. Presented solution should also be resistant for side channel attacks and information about Y coordinate should not be lost (using for example Brier-Joye ladder such information may be lost). If coefficient A in equation of curve ESW : y2 =x3+Ax+B in short Weierstrass curve is not of special form, presented solution is up to 30% faster than classic approach. If A=−3, proposed method may be up to 24% faster.
[ Bibtex Plain ]
Rudy Yuwono, Endah Budi Purnomowati and Mohamad Yasir Amri
Curved-Pentagonal Planar Monopole Antenna for UHF Television Broadcast Receiving Antenna
A 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.
[ Bibtex Plain ]
Ryszard Strużak, Terje Tjelta and José P. Borrego
On Radio-Frequency Spectrum Management
This article review lessons learned from the uses of radio-frequency (RF) spectrum at national and international scales. Its main purpose is to stimulate debate on how to allow new wireless systems to operate, and to reduce the chronic apparent shortage of RF spectrum. The article aims at a better understanding of the mechanisms behind spectrum management and their pertinence to the public interest. The main contributions if the article are:
• Considering RF spectrum management as a construct that structures radio services and, at the same time, distributes wealth and power;
• Highlighting major doctrines of RF spectrum management;
• Promoting spectrum management directly by its users;
• Promoting cooperation and transparency.
The several parts of the paper include the evolution of spectrum exploitation, and a foreseeable future by taking a closer look at major dilemmas and challenges. The paper ends with general comments and conclusions.
[ Bibtex Plain ]