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Characteristics of moored ship oscillations due to long-period waves

30th International Conference on Coastal engineering, ICCE 2006

作者： Uzaki, Ken-Ichi Matsunaga, Nobuhiro Nishii, Yasuhiro Ikehata, Yoshito Kishira, Yasuharu Marine Environment and Engineering Department Port and Airport Research Institute 3-1-1 Nagase Yokosuka Kanagawa 239-0826 Japan Department of Earth System Science and Technology Kyushu University 6-1 Kasuga-koen Kasuga Fukuoka 816-8550 Japan Research Section Sanyo Consultants Co. Ltd. 3-14-7 Kyomachi Kokurakita Kitakyushu Fukuoka 802-8534 Japan Department of Civil Engineering Faculty of Engineering 1727 Ichigi Oita Oita 870-0397 Japan Fukuoka Branch Taiyo-kiso Co. Ltd. 4-1-29 Tenjin Chuo Fukuoka Fukuoka 810-0001 Japan

ISBN: (纸本)9789812706362

In the Port of Shibushi in Japan, problems arise due to long-period oscillations of moored ships when there is a typhoon located far offshore. To investigate the detailed processes of these oscillations and develop effective countermeasures, image processing, wave observations and numerical simulations were conducted. The image processing results showed obvious surging motions of large cargo vessels with a period of about 60-70 s. The results of wave observations showed the existence of waves with long periods of 60-70 s. Numerical simulations revealed that such long-period waves were generated when the peak period of incident waves was set to 120 s as observed. These findings show that small-scaled harbor oscillations occur inside the port. © 2007 World Scientific Publishing Co. Pte. Ltd.

关键词： Image processing

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Dynamical Properties of a Plastic Neural Network Model for Tinnitus Therapy and Inhibition of Oscillation Using Noise Stimulus

Dynamical Properties of a Plastic Neural Network Model for T...

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29th Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBS 2007), vol.6

作者： Ken'ichi Fujimoto Hirofumi Nagashino Yohsuke Kinouchi Ali A. Danesht Abhijit S. Pandya School of Health Sciences Faculty of Medicine University of Tokushima Tokushima Japan Department of Life System Institute of Technology and Science University of Tokushima Tokushima Japan Department of Communication Sciences and Disorders Florida Atlantic University Boca Raton FL USA College of Engineering and Computer Science Florida Atlantic University Boca Raton FL USA

Tinnitus is the perception of phantom sounds in the ears or in the head. Sound therapy techniques for tinnitus have been proposed. To account for mechanisms of tinnitus generation and the clinical effects of sound therapies from the viewpoint of neural engineering, we have proposed a plastic neural network model for the human auditory system. We found that this model has a bistable state, i.e., a stable oscillatory state and a stable equilibrium (non-oscillatory) state coexist at a certain parameter region. We also found that the oscillation can be inhibited by supplying sinusoidal stimulus, which is hypothesized as sound for treatment of tinnitus, to the model. By hypothesizing that the oscillation and the equilibrium correspond to generation and inhibition of tinnitus, respectively, we reported that these phenomena could explain the fact that the habituated human auditory system temporarily halts perception of tinnitus following sound therapy. This paper describes dynamical properties of the model and inhibition of the oscillation for two kinds of noise stimuli which correspond to sound for treatment of tinnitus in clinical. Through numerical simulations we found that adequate noise stimulus can inhibits the oscillation.

关键词： Plastics Neural networks Medical treatment Acoustic noise Humans Auditory system Imaging phantoms Ear Neural engineering Numerical simulation

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Pb-free BGA Solder Joint Reliability Improvement with Sn3.5Ag Solder Alloy on Ni/Au Finish

Pb-free BGA Solder Joint Reliability Improvement with Sn3.5A...

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IEEE/CHMT(CPMT) International Electronics Manufacturing technology Symposium

作者： Eu Poh Leng Min Ding Wayne Lindsay Sheila Chopin Ibrahim Ahmad Azman Jalar Freescale Semiconductor Malaysia Sdn Bhd Petaling Jaya Malaysia Freescale Semiconductor Inc. Austin TX USA Faculty of Engineering Department of Electrical Electronics & System National University of Malaysia Bangi Selangor Darul Ehsan Malaysia Faculty of Science and Technology National University of Malaysia Bangi Selangor Darul Ehsan Malaysia

In this work, Sn3.5Ag solder alloy was being studied for the purpose of Pb-free solder joint reliability improvement over conventional Sn3.8AgO.7Cu solder balls on Ball Grid Array (BGA) packages with Ni/Au pad finishing. The study was carried out in different levels. At individual solder joint level, Sn3.5Ag showed no intermetallic brittle failure in cold ball pull test even up to 6times multiple reflow and 168 hrs high temperature storage for TBGA & TePBGA, and 504 hrs high temperature storage for PBGA Spanish Oak. In contrast, 70-100% of the failure mode of SAC387 was brittle failure. At package level, Sn3.5Ag survived 8~10x more drop cycles than SAC387 in tray drop and packing drop tests. These results indicate that the mechanical strength of Sn3.5Ag on Ni/Au pad is considerably stronger than that of SAC387. The difference in mechanical strength between the two alloys was correlated to their microstructures. At the same time, board level solder joint reliability tests such as thermal cycling and mechanical bend test were carried out. Sn3.5Ag showed better or similar performance as SAC387.

关键词： Soldering Gold alloys Nickel alloys Testing Intermetallic Temperature Electronics packaging Microstructure Stress Semiconductor device reliability

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Inhibition of negative differential resistance in modulation-doped n-type GaxIn1−xNyAs1−y∕GaAs quantum wells

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Physical Review B 2007年第20期75卷 205316-205316页

作者： Y. Sun M. P. Vaughan A. Agarwal M. Yilmaz B. Ulug A. Ulug N. Balkan M. Sopanen O. Reentilä M. Mattila C. Fontaine A. Arnoult Department of Electronic System Engineering University of Essex Wivenhoe Park Colchester CO4 3SQ United Kingdom Faculty of Arts & Science Department of Physics Akdeniz University Antalya Turkey Micro and Nanosciences Laboratory Helsinki University of Technology P.O. Box 3500 Helsinki 02015 Finland Laboratory for Analysis and Architecture of System 7 Avenue du Colonel Roche 31077 Toulouse Cedex 4 France

We present the results of hot-electron momentum relaxation studies for longitudinal transport in modulation doped GaxIn1−xNyAs1−y∕GaAs quantum wells. Experimental results show that the high field drift velocity saturates at a value close to 1×107cm∕s with no evidence for negative differential resistance or instabilities. Experimental results are compared with a simple theoretical model for transport taking into account the effect of nonequilibrium phonon production. Model calculations indicate that enhanced momentum scattering for electrons with nondrifting hot phonons may be the cause for the reduction in drift velocity.

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The Effect of Ni Thickness on Mechanical Strength of Pb-free BGA Spheres on Selectively Plated Ni/Au Finish

The Effect of Ni Thickness on Mechanical Strength of Pb-free...

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IEEE/CHMT(CPMT) International Electronics Manufacturing technology Symposium

作者： Eu Poh Leng Min Ding Joah Rayos Ibrahim Ahmad Azman Jalar Cui Cheng Qiang Freescale Semiconductor Malaysia Sdn. Bhd. Petaling Jaya Malaysia Freescale Semiconductor Inc. Austin TX USA Faculty of Engineering Department of Electrical Electronics & System National University of Malaysia Malaysia Faculty of Science and Technology National University of Malaysia Bangi Selangor Darul Ehsan Malaysia Compass Technology Co Limited New Territories Hong Kong China

As the world is changing to Pb-free solder per EU ROHS Directive, the higher reflow temperature requirement for Pb- free solder has demanded better substrate metal trace to solder mask adhesion to prevent delamination problem. Hence, selective Ni/Au plating process becomes more appealing in the fabrication of substrates to support Pb-free Semiconductor BGA product packaging. However, the set back of selective plating substrate is weaker Pb-free solder joint that leads to higher brittle fracture rate induced by shocking/knocking activities during assembly, test and shipping. In this work, Tape BGA (TBGA) substrates with 3 different Ni thicknesses (range from 2 to 10 mum) were built and attached with Sn3.8Ag0.7Cu Pb-free spheres. Mechanical tests were performed on 2 different levels to examine the strength of the solder joint. On solder joint level, cold ball pull (CBP) and ball shear were used to evaluate the adhesion strength of individual solder joint at Time Zero, after 6 times multiple reflow, and after 168 hours of high temperature storage. The brittle fracture failure rate from this test is believed to have correlation to the missing ball rate in the field. On package level, the tray drop test and packing drop test were conducted to provide a close resemblance to real handling and shipping conditions. Cross-sectioning and SEM investigation were carried out to obtain information on the morphology of intermetallic layer as well as solder mask opening profile. Based on this study, it is determined that the thickness of the Ni needs to be over a certain value (~5.5 mum for Tape BGA) to achieve optimum mechanical strength. By increasing the Ni thickness, the mechanical strength of the thicker Ni solder joint is expected to increase by at least 15% as shown in CBP result, with 3 to 4 times higher resistance against brittle fracture during handling and shipping as demonstrated by tray and packing drop-till-fail test result using center pedestal support trays.

关键词： Gold Testing Soldering Substrates Temperature Adhesives Delamination Fabrication Semiconductor device packaging Lead

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Fairness and utilization in multipath network flow optimization

Fairness and utilization in multipath network flow optimizat...

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2006 IEEE International Conference on Industrial Informatics, INDIN'06

作者： Ishida, Tatsuo Ueda, Kengo Yakoh, Takahiro Center for System Integration Engineering School of Integrated Design Engineering Keio University Department of System Design Engineering Faculty of Science and Technology Keio University

ISBN: (纸本)0780397010

Multipath routing is expected to improve the degree of control in network flow managements. Therefore, multicriteria designs will become indispensable for the next generation of multipath routing algorithms and protocols. This paper shows a theoretical approach to multipath routing problems as a multi-objective optimization of network flows. Two objectives, total link utilization and bandwidth fairness for connections, are introduced into an objective formulation which is solved with a nonlinear programming solver. The numerical analysis shows that drastic fairness improvement can be achieved with small decline of utilization. Compared to standard multipath routing, this approach of bandwidth fair multipath routing can achieve a variance of bit-rate for all connections of 0.0123% with a decline of utilization of 11.4%. In case of single path, a variance of 0.0168% with decline of utilization of 39.7% can be achieved. Finally, the controllability of multipath routing is discussed. © 2006 IEEE.

关键词： Broadband networks

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CONTROL system design CONSIDERING A TRADEOFF BETWEEN EVALUATED UNCERTAINTY RANGES AND CONTROL PERFORMANCE

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Asian Journal of Control 2008年第1期1卷

作者： Y. Wakasa Y. Yamamoto Dept. of Applied Analysis and Complex Dynamical Systems Graduate School of Informatics Kyoto University Kyoto Japan. Yuji Wakasa was born in Okayama Japan in 1968. He received the B.S. and M.S. degrees in engineering from Kyoto university Japan in 1992 and 1994 respectively. From 1994 to 1998 he was a Research Associate in the Department of Information Technology Okayama University. Since April 1998 he has been a Research Associate in the Graduate School of Informatics Kyoto University. His current research interests include robust control and control system design via mathematical programming. Yutaka Yamamoto received his B.S. and M.S. degrees in engineering from Kyoto University Kyoto Japan in 1972 and 1974 respectively and the M.S. and Ph.D. degree in mathematics from the University of Florida in 1976 and 1978 respectively. From 1978 to 1987 he was with Department of Applied Mathematics and Physics Kyoto University and from 1987 to 1997 with Department of Applied System Science. Since 1998 he is a professor at the current position. His current research interests include realization and robust control of distributed parameter systems learning control sampled-data systems and digital signal processing. Dr. Yamamoto is a receipient of the Sawaragi memorial paper award (1985) the Outstanding Paper Award of SICE (1987) Best Author Award of SICE (1990) the George Axelby Outstanding Paper Award of IEEE CSS in 1996 Takeda Paper Prize of SICE in 1997. He is a Fellow of IEEE. He was an associate editor of Automatica. He is currently an associate editor of IEEE Transactions on Automatic Control Systems and Control Letters and Mathematics of Control Signals and Systems. He is a member of the IEEE the Society of Instrument and Control Engineers (SICE) and the Institute of Systems Control and Information Engineers.

This paper presents a design method of control systems such that a designer can flexibly take account of tradeoffs between evaluated uncertainty ranges and the level of control performance. The problem is reduced to a BMI problem and approximately solved by LMIs. The convergence of the proposed approximation is proved in a modified sense. A numerical example shows the effectiveness of the proposed method in comparison with the standard robust control.

关键词： Control system design LMI BMI tradeoff curves

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A controller design method of bilateral control system

A controller design method of bilateral control system

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作者： Tsuji, Toshiaki Natori, Kenji Nishi, Hiroaki Ohnishi, Kouhei Department of System Design Engineering Faculty of Science and Technology Keio University Yokohama Japan Keio University Japan Keio University Yokohama Japan

Haptic sense is indispensable for skillful operation in a telerobotic system. Bilateral control attracts considerable interest because it transfers the haptic sense to a remote place. Although it is simply composed of two manipulators, its design is complicated. This study proposes an idea that provides a new framework on design of a bilateral control system. The idea is to design the bilateral control system based on a "function", a minimum component of a system role. It enables simple and explicit design for various tasks. The features of the proposed method provide a way to design an adjustable system. Experimental results show the validity of the proposed method.

关键词： Control system analysis

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Iterative tuning of feedforward and feedback controllers with physical parameter identification for two-mass system

IEEJ Transactions on Electronics, Information and Systems

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IEEJ Transactions on Electronics, Information and systems 2006年第4期126卷 533-541+15页

作者： Nilkhamhang, Itthisek Sano, Akira Graduate School of Science and Technology Keio University 3-14-1 Hiyoshi Yokohama 223-8522 Japan Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Yokohama 223-8522 Japan Keio University Japan Department of System Engineering Keio University Japan Department of System Design Keio University Japan

This paper proposes a novel algorithm for iterative tuning of a completely unknown two-mass torsional motor system. The command generator tracking (CGT) theory is used to formulate a feedforward controller that consists of a reference model and input generator, which can clarify the relationship between the controller parameters and the two-mass model parameters. The relationship is used to construct physical model parameter estimates, which are shown to converge to true values as the output error is minimized. The proposed tuning process is conducted by utilizing these estimates at each iteration to approximate a system transfer function. This allows the analytical calculation of controller gradients needed for conducting Iterative Feedback Tuning (IFT), without having to perform additional experiments for gradient estimation. The effectiveness of the proposed method in achieving trajectory tracking and identification of all physical parameters is demonstrated via experimentation.

关键词： Feedback control

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Stability Feeler: A tool for analysis of polytopic polynomials

IEEJ Transactions on Electronics, Information and Systems

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IEEJ Transactions on Electronics, Information and systems 2006年第11期126卷 1311-1317+7页

作者： Matsuda, Tadasuke Kawabata, Keishi Mori, Takehiro Department of Electronics and Information Science Faculty of Engineering and Design Kyoto Institute of Technology Goshokaidocho Sakyo-ku Kyoto 606-8585 Japan Kyoto Institute of Technology Japan

Stability analysis of a linear uncertain polynomial system in real parameter space is one of central themes of recent control theory. It is generally very difficult to analyze the stability of such a system because the number of its characteristic polynomials to be analyzed becomes enormous. A parallelotope of polynomials is a typical type of uncertain polynomials. Though a number of analysis methods for such a parallelotope are at our hand, they mainly focus on stability check of given polynomials and hardly give information on how for the certain interested parameter can be extended for stability. To solve this problem, we propose a novel tool for stability analysis called "Stability Feeler". This concept leads to an algorithm which determines D-stability intervals along a given line in the polynomial coefficient space. With the tool, stability problems of parallelotopes can be successfully resolved. Two numerical examples are shown to support this concept.

关键词： Control theory

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