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Efficient Channel Assignment technique providing priority to Emergency Calls in Wireless Cellular Security Networks

WSEAS Transactions on Communications 2006年第1期5卷 84-91页

作者： Ioannou, K. Dimitriadou, E. Ioannou, A. Panoutsopoulos, I. Garmpis, A. Kotsopoulos, S. Wireless Telecommunication Laboratory Department of Electrical and Computer Engineering University of Patras Rion 26500 Patras Greece OTE S.A. Messolonghi 30200 Greece Department of Applied Informatics in Management and Economy Technological Educational Institution of Messolonghi Messolonghi 30200 Greece

In this paper is presented a new efficient Channel Assignment technique. The philosophy of this technique is that provides priority to Emergency Calls in Wireless Cellular Security Networks. The new technique is based on a two-layer cellular architecture The lower layer of the proposed architecture is based on a microcellular solution, for absorbing the traffic loads of both the handoff and new calls of Emergency Calls (EC). The higher layer is based on a macro-cell umbrella solution, for absorbing the traffic load of the handoff and new calls of the Non Emergency Calls (NEC). The simulation results show that using the optimum number of channels in each layer, the QoS of EC and the Handoff Blocking Probability of NEC in a congested area where an extreme event was happened is optimized, having the minimum negative effect on the New Call Blocking Probability of the NEC.

关键词： Wireless telecommunication systems

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ROBUST STABILITY CHECKING OF A CLASS OF LINEAR INTERVAL FRACTIONAL ORDER SYSTEM USING LYAPUNOV INEQUALITY

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IFAC Proceedings Volumes 2006年第11期39卷 89-94页

作者： Hyosung Ahn YangQuan Chen Igor Podlubny Center for Self-Organizing and Intelligent Systems (CSOIS) Department of Electrical and Computer Engineering Utah State University Logan UT 84322-4160 USA Department of Applied Informatics and Process Control Technical University of Kosice B. Nemcovej 3 04200 Kosice Slovak Republic

This paper provides a new analytical robust stability checking method of fractional-order linear time invariant interval uncertain system. This paper continues the authors’ previous work (Chen et al., 2005a) where matrix perturbation theory was used. For the new robust stability checking, Lyapunov inequality is utilized for finding the maximum eigenvalue of a Hermitian matrix. Through numerical examples, the usefulness and the effectiveness of the newly proposed method are verified.

关键词： Fractional order linear dynamic systems robust stability interval linear time invariant systems interval matrix

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Average Row Thresholding Method for Mammogram Segmentation

Average Row Thresholding Method for Mammogram Segmentation

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： A.A. AbuBaker R.S. Qahwaji M.J. Aqel M.H. Saleh School of Informatics University of Bradford Bradford West Yorkshire UK EMIC school of Informatics University of Bradford Bradford West Yorkshire UK University of Bradford Bradford West Yorkshire UK Electrical and Computer Engineering Department University of Applied Science University Jordan

Two novel threshold techniques are proposed for image segmentation which is a very critical task in any image processing. The two methods are based in scanning each image row by row and to find the proper threshold value. A modification of this method is developed to find the threshold value by average. The two methods are implemented on a mammogram and accordingly, a comparison between the two methods is carried out

关键词： Image segmentation Entropy Histograms Image processing Image edge detection informatics Digital images Image analysis Neural networks Fuzzy neural networks

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A new tree based call admission control for wireless networks

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WSEAS Transactions on Systems 2006年第3期5卷 504-509页

作者： Ioannou, K. Pylarinos, J. Louvros, S. Panoutsopoulos, I. Kougias, I. Garmpis, A. Kotsopoulos, S. Wireless Telecommunication Laboratory Department of Electrical and Computer Engineering University of Patras Rion 26500 Patras Greece Department of Communications Systems and Networks Technological Educational Institution of Messolonghi Nafpaktos 30300 Greece Department of Applied Informatics in Management and Economy Technological Educational Institution of Messolonghi Messolonghi 30100 Greece

Microcellular solutions in wireless networks increase the network traffic control as a result of frequent handover behavior. This paper proposes a two layer wireless call admission control to optimize the forced termi... 详细信息

关键词： Wireless telecommunication systems

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Experimental performance evaluation of the emerging WiMAX technology

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WSEAS Transactions on Information Science and Applications 2006年第2期3卷 322-327页

作者： Agapiou, G. Vali, D. Charalambakis, D. Georgiadis, P. Plakidis, E. Rorris, P. Ioannou, K. Garmpis, A. Mobile and Radio Communications Research Laboratories OTE S.A. Athens Greece Wireless Telecommunication Laboratory Department of Electrical and Computer Engineering University of Patras Rion 26500 Patras Greece Department of Applied Informatics in Management and Economy Technical Education Institute of Messologi Messologi Greece

The increasing demand for wireless broadband service offering in long distances is the major drive behind the emergence of the WiMAX technology. WiMAX is targeted to providing high bit data rates to the end users in a wireless manner, any time, in any location, even in harsh environmental conditions and at an acceptable quality. This paper presents the experimental results of a WiMAX system that follows the specifications of IEEE 802.16-2004 standard. Throughput and Bit Error Rate (BER) measurements, as well as voice and video service experiments are carried out, leading to useful conclusions for the performance evaluation of the WiMAX system under test and the WiMAX technology in general.

关键词： Wireless telecommunication systems

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Throughput and interference measurements in copper wires of xDSL type modems

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WSEAS Transactions on Information Science and Applications 2006年第2期3卷 352-357页

作者： Agapiou, G. Doukoglou, T. Georgiadis, P. Georgakopoulos, G. Plakidis, E. Rorris, P. Ioannou, K. Ioannou, A. Garmpis, A. Mobile and Radio Communications Research Laboratories OTE S.A. Athens Greece Wireless Telecommunication Laboratory Department of Electrical and Computer Engineering University of Patras Rion 26500 Patras Greece Department of Applied Informatics in Management and Economy Technical Education Institute of Messologi Messologi Greece

Crosstalk is an important factor that needs to be considered and study its effects in copper wires, especially when voice communication takes place. Its presence has proven to be an impaired factor in the performance of communication services. This paper measures the isolation losses and the crosstalk losses as a function of the frequency and the length of the copper wires. It also presents throughput results from modems designed in the context of an EU financed project that can provide a symmetric 100 Mbps over two pairs for reach up to 500m (5 times the existing reach of 100-BASE-T systems).

关键词： Modems

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Low HRV entropy is strongly associated with myocardial infarction

Low HRV entropy is strongly associated with myocardial infar...

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作者： Lau, Stephan Haueisen, Jens Schukat-Talamazzini, Ernst G. Voss, Andreas Goernig, Matthias Leder, Uwe Figulla, Hans-R. Institute of Computer Science Friedrich Schiller University Jena Jena Germany Biomagnetic Center Jena Friedrich Schiller University Jena Jena Germany Department of Medical Engineering University of Applied Sciences Jena Jena Germany Institute of Biomedical Engineering and Informatics Technical University of Ilmenau Ilmenau Germany Clinic of Internal Medicine I Friedrich Schiller University Jena Jena Germany Biomagnetic Center Jena Friedrich Schiller University Jena Erlanger Allee 101 07747 Jena Germany

Heart rate variability (HRV) is a marker of autonomous activity in the heart. An important application of HRV measures is the stratification of mortality risk after myocardial infarction. Our hypothesis is that the information entropy of HRV, a non-linear approach, is a suitable measure for this assessment. As a first step, to evaluate the effect of myocardial infarction on the entropy, we compared the entropy to standard HRV parameters. The entropy was estimated by compressing the tachogram with Bzip2. For univariate comparison, statistical tests were used. Multivariate analysis was carried out using automatically generated decision trees. The classification rate and the simplicity of the decision trees were the two evaluation criteria. The findings support our hypothesis. The meanNN-normalized entropy is reduced in patients with myocardial infarction with very high significance. One entropy parameter alone exceeds the discrimination strength of multivariate standards-based trees. ©2006 by Walter de Gruyter.

关键词： Cardiology

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Variable Forgetting Factor-Based Friction Compensation Method of Precision Stages

Variable Forgetting Factor-Based Friction Compensation Metho...

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SICE Annual Conference

作者： Shigeki Goka Seiji Hashimoto Kiyoshi Ohishi Takeo Ishikawa Shuichi Adachi Koji Kosaka Hiroshi Kubota Tadahiro Ohmi Department of Electronic Engineering Gunma University Gunma Japan Department of Electrical Engineering Nagaoka University of Technology Niigata Japan Department of Applied Physics and Physico-Informatics Keio University Kanagawa Japan Tech Concierge Kumamoto Kumamoto Japan Department of Electrical and Computer Engineering Kumamoto University Kumamoto Japan Future Information Industry Creation Center University of Tohoku Miyagi Japan

This paper presents the nonresonant ultrasonic motor (SPIDER)-driven precision stage control based on an adaptive identification method with a variable forgetting factor (VFF). SPIDER-driven stage has a strong non-linearity due to the frictional drive mechanism. Focusing on the VFF, dynamical change of frictional property is detected. Therefore, fast and precise friction compensation can be performed based on the VFF. The validity of both the identification and compensation methods is verified through experiments

关键词： Friction Leg Electronics industry Actuators Position measurement Industrial electronics Physics computing computer industry Industrial control Electric variables control

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Building a multimedia next generation network

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WSEAS Transactions on Communications 2006年第2期5卷 225-230页

作者： Raptis, L. Kagklis, D. Patikis, Y. Hatzilias, G. Zervos, N. Zahariadis, T. Crhonis, D. Ioannou, K. Garmpis, A. Department of Electrical Engineering and Computer Science National Technical University of Athens 9 Heroon Polytechniou 15773 Zographou Athens Greece Ellemedia Technologies Ltd. 223 Syggrou Av. GR-17121 Athens Greece Hellenic Telecommunications Organization S.A. 99 Kifissias Ave. 151 24 Athens Greece Wireless Telecommunication Laboratory Department of Electrical and Computer Engineering University of Patras Rion 26500 Patras Greece Department of Applied Informatics in Management and Economy Technological Educational Institution of Messolonghi Messolonghi 30100 Greece

The last years, the voice and the Internet access services have become a commodity, having as a result the offering from network providers, both fixed and mobile, a bunch of services. These developments are posing new requirements to existing networks, which are circuit based, and an evolution path is needed towards next generation networks, which allows the provision of multimedia services with guarantee quality of service. Mobile operators are facing the greatest challenges, since they have to reform their networks in order to provide data and multimedia services and the definition of the IP multimedia Subsystem (IMS) framework is one step towards that direction. The purpose of this paper is to shed light on significant issues, in terms of network architecture and protocols of multimedia next generation networks,,allowing the definition of an evolution scenario of existing networks towards next generation multimedia networks.

关键词： Telecommunication services

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Efficient SIE/VIE scattering analysis of ferroelectric inhomogeneous materials with high permittivity for microwave applications

Efficient SIE/VIE scattering analysis of ferroelectric inhom...

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European Conference on Antennas and Propagation, EuCAP

作者： Georgios K. Avdikos Theodore Zervos Hristos T. Anastassiu Nikolaos K. Uzunoglu School of Applied Mathematics and Physics National and Technical University of Athens Zografou Greece National Centre for Scientific Research Demokritos Institute of Informatics and Telecommunications Athens Greece Communications and Networks Design & Development Department Hellenic AeroSpace Industry SA Viotia Greece School of Electrical and Computer Engineering National and Technical University of Athens Zografou Greece

Ferroelectric materials have been gaining much interest over the last decades due to the unique operational characteristics they demonstrate, when a dc electric field is applied. This paper investigates the scattering analysis of electromagnetic waves from materials with high permittivity that follows a linear spatial variation along one axis. The surface integral equation (SIE) and volume integral equation (VIE) methods are invoked to compute the currents and the radar cross section (RCS). The number of unknowns for the VIE is, as expected, larger than for the SIE method. The RCS and the induced current are associated in such a way that one can approximate the linear variation with relatively few elements (unknowns).

关键词： Ferroelectric materials Permittivity Electromagnetic scattering Radar scattering Integral equations Electromagnetic analysis Radar cross section Linear approximation Dielectric materials Microwave antenna arrays

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