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International Conference on Telecommunications Energy (INTELEC)

作者： A. Katsuki T. Matsumoto Department of Computer Science and Electronics Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Fukuoka Japan

The powered terminal in most wire communication systems needs to separate AC signals and DC supply power in its input part connected to the communication lines. Well-known separators usually utilize a combined circuit of inductors and capacitors. When the lowest frequency of the signal is low, the inductance becomes high and the size of the inductor increases. Our original communication system consists of low-power DC-DC converters. Because a converter in the powering terminal operates not only as power supply but also as transmitter, it is preferable that the electronic choke be bidirectional. A new balanced-type low-loss electronic choke having small inductors and an amplifier is proposed in this paper.

关键词： Inductors Wire Power supplies Particle separators Circuits Capacitors Frequency Inductance DC-DC power converters Transmitters

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Optical waveguide coupler fabrication based on time variation ion-exchange technique

Optical waveguide coupler fabrication based on time variatio...

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2004 IEEE International Conference on Semiconductor electronics, ICSE 2004

作者： Leong, Kok Swee Shaari, Sahbudin IEEE SPIE Faculty of Electronics and Computer Engineering Kolej Universiti Teknikal Kebangsaan Malaysia 75450 Ayer Keroh Melaka Malaysia Photonics Technology Laboratory Institute of Micro-Engineering and Nanoelectronics Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia

ISBN: (纸本)0780386582

Optical power transfer in a planar waveguide directional coupler is dependent on the geometry and refractive indices of the two waveguides. A method for fabricating optical directional couplers using ion-exchange Ag +/K+/Ca+ processes is presented, where the time of ion-exchange process is used to control the ratio of output power at the two output ports at a fixed temperature of 300C. As far as the device geometry is still in single-mode regime, this method eliminates the need for high-resolution lithography for producing exact geometry of the device. © 2004 IEEE.

关键词： Ion exchange

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Enhancement of stents using interference of low-frequency ultrasonic echo signals

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Journal of Medical Ultrasonics 2004年第2期31卷 67-73页

作者： Ohashi, Gosuke Ohya, Akihisa Tobise, Kazimobu Akiyama, Iwaki Faculty of Engineering Shizuoka University Hamamatsu Japan Institute of Information Sciences and Electronics University of Tsukuba Tsukuba Japan Shoryo Electronic Corporation Kamakura Japan Faculty of Engineering Shonan Institute of Technology Fujisawa Japan Image Processing and Vision Research Laboratory Department of Electrical and Computer Engineering University of California at Santa Barbara Santa Barbara CA 93106-9560 United States

Purpose. We set out to enhance the imaging of stents used for coronary coarctation surgery without imaging the reticulation of the stent. Because the stent is a reticulated structure, there is a relation between ultrasound wavelength and the interstice reticulation that produces the echo. Methods. First we performed computer simulation by ultrasound frequency of transmitted signals to analyze this relation. Then, instead of controlling the transmitted wave, we processed the returned signals through a band-pass filter because of the difficulty of controlling the transmitted waves of diagnostic ultrasound equipment. Following this, we conducted experiments on an agar gel phantom containing a stent to verify the effectiveness of this method. Results. The simulation confirmed that the stent was apparent when the ultrasonic wavelength equaled the product of an integer and twice the interval of the reticulation of the stent. Application of a band-pass filter of 0.8 to 1.5MHz to the waveform returned from the agar gel phantom containing the stent. Conclusions. The effectiveness of this method in depicting the stent was confirmed. © The Japan Society of Ultrasonics in Medicine 2004.

关键词： Interference Received waveform Signal processing Stent Ultrasonic echography

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Non-symmetric Mach-Zehnder interferometer wavelength filter

Non-symmetric Mach-Zehnder interferometer wavelength filter

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2004 IEEE International Conference on Semiconductor electronics, ICSE 2004

作者： Kok, Swee Leong Shaari, Sahbudin IEEE SPIE Faculty of Electronics and Computer Engineering Kolej Universiti Teknikal Kebangsaan Malaysia 75450 Ayer Keroh Melaka Malaysia Photonics Technology Laboratory Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia

ISBN: (纸本)0780386582

A non-symmetrical Mach-Zehnder configuration with corrugated waveguide at one of its arm which acts as an interferometer is presented. The interference output intensity of the input light power depends on the operating wavelength, hence acting as a wavelength filter. The function of this wavelength filter is demonstrated by beam propagation method within range from 1000nm to 1800nm. © 2004 IEEE.

关键词： Beam propagation method

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A new task scheduling method for distributed programs which require memory management in grids

A new task scheduling method for distributed programs which ...

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Workshops on Applications and the Internet (SAINT)

作者： H. Koide Y. Oie Department of Artificial Intelligence Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Fukuoka Japan Department of Computer Science and Electronics Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Fukuoka Japan

In the grid applications, it is very likely that object oriented languages, like Java and Ruby, are employed as well as large-scale semi-structured data like XML. However, their inherent dynamic memory management has to suspend the execution of all the tasks running on processors when it is invoked. This adversely affects the grid computing severely unless the task scheduling system can avoid it with some special mechanism. We propose a new task scheduling method, referenced to as CP/MM, which can efficiently schedule tasks for applications requiring memory management. The underlying concept is to consider the cost due to memory management when the task scheduling system allocates ready coarse grain tasks, or macro-tasks, to processors. We have developed three task scheduling modules including an implementation of CP/MM into a task scheduling system is implemented on Java RMI (remote method invocation) communication infrastructure. Moreover, we evaluate the fundamental performance of CP/MM in two ways. The first is the performance evaluation of CP/MM which is applied to a small but practical test application program on a PC cluster. The second is the performance evaluation for test programs which have many tasks with complicated dependency relations on the test bed system consisting of computers on our two campuses located at a distance of approximately 32 km. These experimental results show that CP/MM can successfully prevent high priority macro-tasks from being affected by the garbage collection arising from the memory management, so that CP/MM can efficiently schedule distributed programs whose critical paths are relatively long.

关键词： Memory management Processor scheduling Grid computing Large-scale systems computer networks Java Application software computer science XML Data engineering

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Distributed denial of service detection using TCP/IP header and traffic measurement analysis

Distributed denial of service detection using TCP/IP header ...

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International Symposium on Communications and Information Technologies (ISCIT)

作者： L. Limwiwatkul A. Rungsawang National Electronics and Computer Technology Center Klong Luang Pathum Thani Thailand Massive Information & Knowledge Engineering Department of Computer Engineering Faculty of Engineering Kasetsart University Bangkok Thailand

Recently, the detection of distributed denial of service (DDoS) and the discovery of DDoS attacking signature used the mean of traffic measurement analysis at protocol level. This technique is not suited to find the signatures of DDoS attack, which is formless. Also, DDoS is in general the combination of different forms of denial of service (DoS). As a result, it is difficult to find the exact signature of attack. Moreover, it is very difficult to distinguish the difference between an unusual high traffic which is caused by the attack, and the flash crowds which normally occur when a huge number of users use the target machine at the same time. In fact, this difference should only be observed from analyzing the data in the packet header. In this paper, we propose to discover the DDoS attacking signature by analyzing the TCP/IP packet header against the well defined rules and conditions, and distinguish the difference between normal and abnormal traffic. We here observe three groups or delegates of DDoS attacking, i.e., ICMP flood, UDP flood and TCP SYN flood, and present convincing preliminary experiments.

关键词： computer crime TCPIP Floods Knowledge engineering Protocols Bandwidth Internet IP networks Electronic mail Data analysis

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Dual-band miniaturized microstrip fractal antenna for a small GSM 1800 + UMTS mobile handset

Dual-band miniaturized microstrip fractal antenna for a smal...

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Mediterranean Electrotechnical Conference (MELECON)

作者： J. Guterman A.A. Moreira C. Peixerio Faculty of Electronics and Information Technology Warsaw University of Technology Poland Department of Electrical and Computer Engineering Instituto Superior Técnico Lisboa Portugal

A novel microstrip GSM1800 + UMTS dual-band antenna based on a Koch fractal shaped patch element is presented. The antenna has been developed to be used in small handsets of future multi-standard mobile communication systems. The fractal miniaturization technique has been combined with a patch inverted F antenna (PIFA) structure. The effect of a small ground plane has been taken into account. The antenna prototype has been fabricated and tested. Good agreement has been obtained between numerical simulations and experimental results providing validation of the design procedure.

关键词： Dual band Microstrip antennas Fractal antennas GSM 3G mobile communication Mobile handsets Mobile antennas Telephone sets Mobile communication Prototypes

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Ground plane size effects on a microstrip patch antenna for small handsets

Ground plane size effects on a microstrip patch antenna for ...

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International Conference on Microwaves, Radar and Wireless Communications

作者： R. Urban C. Peixeiro Faculty of Electronics and Information Technology Warsaw University of Technology Poland Department of Electrical and Computer Engineering Instituto Superior Tecnico Technical University of Lisbon Portugal

This work describes the research carried out on small microstrip patch antennas for small handsets. The objective is to study the effects of a small ground plane on a planar inverted-F antenna bandwidth and gain. A wide-band antenna, to be used in mobile communication systems and wireless local area networks applications, has been selected. An antenna prototype has been designed, fabricated and tested. Good agreement has been obtained between theoretical and experimental results.

关键词： Microstrip antennas Patch antennas Telephone sets Bandwidth Broadband antennas Mobile antennas Mobile communication Wireless LAN Prototypes Testing

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Triple-band miniaturized fractal planar inverted-F antenna for a small mobile terminal

Triple-band miniaturized fractal planar inverted-F antenna f...

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International Conference on Microwaves, Radar and Wireless Communications

作者： J. Guterman A.A. Moreira C. Peixeiro Faculty of Electronics and Information Technology Warsaw University of Technology Poland Department of Electrical and Computer Engineering and Institute for Telecommunications Instituto Superior Technico Lisboa Portugal

A novel triple-band microstrip patch antenna with a Koch pre-fractal edge and a U-slot is proposed for use in the GSM 1800, UMTS and HiperLAN2 bands. A remarkable miniaturization is archived making use of a fractal patch inverted-F antenna (PIFA) structure: a patch of 0.17/spl lambda/ has been designed. The multiband behaviour has been obtained by broadening the lower frequency resonance of the fractal patch to cover GSM 1800 and UMTS, and inserting a U-slot dimensioned for the HiperLAN2 band. The effect of small ground plane has been taken into account. The results confirm that the antenna meets the requirements of multi-standard mobile terminal application.

关键词： Fractals Mobile antennas Microstrip antennas 3G mobile communication Telephone sets Shape Wireless LAN Frequency Patch antennas Resonance

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A noise elimination procedure for wavelet-based printed circuit board inspection system

A noise elimination procedure for wavelet-based printed circ...

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Asian Control Conference

作者： Z. Ibrahim S.A.R. Al-Attas O. Ono M.M. Mokji Department of Electrical and Electronics Engineering School of Science and Technology Meiji University Japan Department of Microelectronics and Computer Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia Malaysia

Image difference operation is frequently used in automated printed circuit board (PCB) inspection system as well as in many other image processing applications. The previously proposed wavelet-based PCB inspection approach also incorporated the point-to-point image difference operation as part of its algorithm. Unfortunately, during the implementation, this operation brings along the unwanted noise due to misalignment and uneven binarization. Thus, this paper proposes a method to eliminate, if possible, or to reduce as much as possible such noise during the computation of defect detection. The results of applying the proposed method showed a significant improvement during the real-time inspection of printed circuit boards.

关键词： Circuit noise Printed circuits Inspection Noise reduction Logic testing Microelectronics Image processing Application software Morphological operations Wavelet transforms

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