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Interaction Between GSM Handset Helical Antenna and User's Head: Theoretical Analysis and Experimental Results

Environmentalist 2005年第2期25卷 215-221页

作者： A. Alexiou P. Kostarakis V. N. Christofilakis T. Zervos A. A. Alexandridis K. Dangakis C. Soras V. V. Petrović B. M. Kolundžija A. R. Dordević Physics Department University of Ioannina Ioannina Greece National Centre for Scientific Research “Demokritos” Institute of Informatics and Telecommunications Athens Greece Department of Electrical & Computer Engineering University of Patras Patras Greece Faculty of Electrical Engineering University of Belgrade Belgrade Serbia

The performance of a cellular phone commercial helical antenna at 900~MHz band, both in free space and in the presence of a human head phantom was studied. Numerical simulation of the phone model for the latter case has been performed giving 3D radiation diagrams. The effect of the phantom head on radiation diagrams is presented. The relative amount of the EM power absorbed in the head was obtained for several distances of the phone. Measurements were carried out in a RF anechoic chamber using standard horn antennas and a calibrated measuring system. Absolute radiation patterns of the antenna gain were obtained in the three principal planes. Significant reduction of the absorbed power could be achieved just by moving the phone 1 cm away from the head.

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An ESR meter for high frequencies

An ESR meter for high frequencies

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Sixth International Conference on Power Electronics and Drive Systems, PEDS 2005

作者： Amaral, Acácio M. R. Cardoso, A. J. Marques Polytechnic Institute of Coimbra ISEC/IT Department of Informatics and Systems Rua Pedro Nunes - Quinta da Nora P - 3030 -199 Coimbra Portugal University of Coimbra FTCUC/IT Department of Electrical and Computer Engineering Pólo II - Pinhal de Marrocos P - 3030 -290 Coimbra Portugal

ISBN: (纸本)0780392965

This paper presents a laboratory method that can be used to determine the intrinsic value of the equivalent series resistance (ESR) of electrolytic capacitors. One of the most critical problems of switch mode DC-DC converter designers is the ESR, which introduces a high A.C. component in the output voltage. Thus, the knowledge of this value at the converter operating conditions is fundamental to predict the output response of the converter. To validate this technique some experimental and simulated results are presented. © 2005 IEEE.

关键词： Electric resistance

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An experimental technique for estimating the aluminum electrolytic capacitor equivalent circuit, at high frequencies

An experimental technique for estimating the aluminum electr...

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2005 IEEE International Conference on Industrial Technology, ICIT 2005

作者： Amaral, Acácio M. R. Cardoso, A. J. Marques Polytechnic Institute of Coimbra ISEC Department of Informatics and Systems Rua Pedro Nunes - Quinta da Nora P - 3030 -199 Coimbra Portugal University of Coimbra FCTUC / IT Department of Electrical and Computer Engineering Pólo II - Pinhal de Marrocos P - 3030 - 290 Coimbra Portugal

ISBN: (纸本)0780394844

This paper presents an experimental technique that allows the determination of the equivalent circuit of an aluminium electrolytic capacitor. The impedance of these electrolytic capacitors changes with frequency, becoming approximately equal to a resistance near their resonance frequency. This resistance, the equivalent series resistance (ESR), becomes one of the most critical problems of static converters, which operate near the resonant frequency of the capacitor. The ESR leads to a significant increase in the alternating (AC) component of the output voltage, requiring a constant action of the control system. To validate this technique some experimental and simulated results are presented. © 2005 IEEE.

关键词： Equivalent circuits

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Searching for meaningful feature interactions with backward-chaining rule induction

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6th International Symposium on Intelligent Data Analysis, IDA 2005

作者： Fisher, Doug Edgerton, Mary Tang, Lianhong Frey, Lewis Chen, Zhihua Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN 37235 United States Department of Pathology Vanderbilt University Medical Center United States Department of Biomedical Informatics Vanderbilt University Medical Center United States Vanderbilt Ingram Cancer Center Vanderbilt University Medical Center United States

ISBN: (纸本)3540287957

Exploring the vast number of possible feature interactions in domains such as gene expression microarray data is an onerous task. We propose Backward-Chaining Rule Induction (BCRI) as a semi-supervised mechanism for biasing the search for plausible feature interactions. BCRI adds to a relatively limited tool-chest of hypothesis generation software, and it can be viewed as an alternative to purely unsupervised association rule learning. We illustrate BCRI by using it to search for gene-to-gene causal mechanisms. Mapping hypothesized gene interactions against a domain theory of prior knowledge offers support and explanations for hypothesized interactions, and suggests gaps in the current domain theory, which induction might help fill. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Information theory

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Planar homography: accuracy analysis and applications

Planar homography: accuracy analysis and applications

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IEEE International Conference on Image Processing

作者： S. Negahdaripour R. Prados R. Garcia Department Electrical and Computer Engineering University of Miami Coral Gables FL USA Computer Vision and Robotics Group Department of Electronics Informatics and Automation University of Girona Spain

Projective homography sits at the heart of many problems in image registration. In addition to many methods for estimating the homography parameters (R.I. Hartley and A. Zisserman, 2000), analytical expressions to assess the accuracy of the transformation parameters have been proposed (A. Criminisi et al., 1999). We show that these expressions provide less accurate bounds than those based on the earlier results of Weng et al. (1989). The discrepancy becomes more critical in applications involving the integration of frame-to-frame homographies and their uncertainties, as in the reconstruction of terrain mosaics and the camera trajectory from flyover imagery. We demonstrate these issues through selected examples.

关键词： Cameras Robotics and automation Image reconstruction Layout Equations Application software computer vision Robot vision systems informatics Heart

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engineering and technology aspects of an e-government architecture based on Web services

Engineering and technology aspects of an e-government archit...

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European Conference on Web Services (ECOWS)

作者： B. Meneklis A. Kaliontzoglou C. Douligeris D. Polemi Department of Informatics University of Piraeus Piraeus Greece School of Electrical & Computer Engineering National and Technical University of Athens Athens Greece

In order for e-government to be successful there is a strong requirement for approaches that are based on widely accepted technical standards and formal design methods. In this paper, we describe the architecture of the eMayor platform, a Web services based platform that is built as a holistic service framework for the deployment and delivery of e-government enterprise services for European municipalities. The design of the platform is based on the ISO/RM-ODP standard. The goal of the paper is to present both a general architectural overview of the platform and its services, along with the engineering and technology aspects of the architecture as instances of the engineering and technology viewpoints of the RM-ODP standard.

关键词： Electronic government Service oriented architecture Web services Design engineering ISO standards Paper technology Buildings Business communication informatics computer security

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A recurrent fuzzy-neural filter for real-time separation of lung sounds

A recurrent fuzzy-neural filter for real-time separation of ...

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International Joint Conference on Neural Networks (IJCNN)

作者： P.A. Mastorocostas J.B. Theocharis Department of Informatics & Communications Technological Educational Institute of Serres Serres Greece Department of Electrical & Computer Engineering Aristotle University of Thessaloniki Thessaloniki Greece

This paper presents a recurrent filter that performs real-time separation of discontinuous adventitious sounds from vesicular sounds. The filter uses two dynamic fuzzy neural networks, operating in parallel, to perform the task of separation of the lung sounds, obtained from patients with pulmonary pathology. Extensive experimental results, including fine/coarse crackles and squawks, are given, and a performance comparison with a series of other models is conducted, underlining the separation capabilities of the proposed filter and its improved performance with respect to its competing rivals.

关键词： Filters Lungs Fuzzy neural networks Electronic mail Pathology Least squares methods Fuzzy systems informatics Communications technology Educational technology

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A Robust BPCS-Steganography against the Visual Attack

A Robust BPCS-Steganography against the Visual Attack

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International Conference on Information, Communications and Signal Processing

作者： M. Niimi H. Noda B. Segee Department of Systems Innovation and Informatics Kyushu Institute of Technology Lizuka Japan Electrical & Computer Engineering Department University of Maine Orono ME USA

This paper discusses a visual attack to BPCS-Steganography (Bit-Plane Complexity Segmentation-Steganography) and presents a countermeasure. BPCS categorizes each small block within cover images into either a "noise-like region" or an "informative region" by means of the binary-image feature called complexity and replaces noisy blocks with the binary patterns mapped from the bit sequences of secret data. The binary patterns must be complex because it is replacing complex regions. If the binary patterns to be inserted are simple, then the logical operation called conjugate operation is applied that transforms a simple pattern to a complex pattern. We need to keep, for each block, the flag called a conjugation flag representing whether or not conjugation had been applied to correctly extract the embedded information. In the case where the conjugation flags must be embedded within cover images, we are unable to use the complexity thresholding for the embedding of the flags. Thus the flags must be embedded into a fixed area. To this effect it is easy to recognize unnatural patterns on the LSB plane of stego-images. It can be used as a signature or a distinguishing mark between natural images and images with information embedded by BPCS. We propose secure BPCS which is robust against the visual attack. It is realized by assigning the meaning of the conjugation flag to a pixel of each block and making the specific rule to embed and extract it

关键词： Robustness Steganography Data mining Image segmentation Technological innovation informatics Pattern recognition Art Digital images Humans

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Edge detection in multispectral remote sensing images

Edge detection in multispectral remote sensing images

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International Conference on Recent Advances in Space Technologies (RAST)

作者： T. Sirin M.I. Saglam I. Erer M. Gokmen O. Ersoy Informatics Institute Advanced Technologies in Engineering Computer Science and Engineering Istanbul Technical University Istanbul Turkey Informatics Institute Advanced Technologies in Engineering Istanbul Technical University Istanbul Turkey Faculty of Electrical and Electronic Engineering Electronics and Communication Department Istanbul Technical University Istanbul Turkey Faculty of Electrical and Electronic Engineering Computer Engineering Department Istanbul Technical University Istanbul Turkey School of Electrical and Computer Engineering Purdue University West Lafayette IN USA

In this paper, we discuss edge detection by first using a clustering algorithm followed by a known edge detection filter such as Canny or generalized edge detector (GED). We developed a new clustering method called Self-Organizing Global Ranking (SOGR). Comparative results with multispectral satellite images including SOGR, SOM and K Means clustering methods are discussed. The results show that the two-stage algorithms are better than single stage edge detector algorithms.

关键词： Image edge detection Remote sensing Clustering algorithms Detectors Filters Clustering methods Laplace equations informatics Image segmentation Biomembranes

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Investigation of EMC in high-speed on-chip transmission lines by a new hybrid quasi-static finite difference-FEM technique

Investigation of EMC in high-speed on-chip transmission line...

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IEEE International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology

作者： T.V. Yioultsis T.I. Kosmanis I.T. Rekanos T.D. Tsiboukis Department of Electrical and Computer Engineering Aristotle University of Thessaloniki Thessaloniki Greece Department of Informatics and Communications Technological Educational Institute of Serres Serres Greece

In this paper we present a new computational technique to investigate wave phenomena and EMC/EMI interactions in high speed transmission lines and interconnects on the chip level. The proposed time-domain method is based on the very different nature of the electromagnetic problem in the conductors and semiconductors, compared to the insulating media that separate conducting regions and fill the intermediate volume. Therefore, the purely static problem in the regions filled with silicon oxide is totally separated from the diffusion problem in the conducting regions. The latter one is solved by means of a simple and efficient DuFort-Frankel technique using finite differences, while the static problem is dealt with by means of a finite element method with coarse meshing, since outside the conductors the field variations are much less intense. In each time step, the problems in the two regions are appropriately coupled by means of proper interface conditions.

关键词： Electromagnetic compatibility Transmission lines Finite difference methods Conductors Insulation Conducting materials Integrated circuit interconnections Time domain analysis Silicon Circuit simulation

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