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DRY AND WET ETCHING WITH (111) SILICON FOR HIGH-PERFORMANCE MICRO AND NANO SYSTEMS

International Journal of Computational engineering Science 2003年第2期4卷 181-187页

作者： DONG-IL "DAN" CHO BYOUNG-DOO CHOI SANGWOO LEE SEUNG-JOON PAIK SANGJUN PARK JAEHONG PARK YONGHWA PARK JONGPAL KIM IL-WOO JUNG School of Electrical Engineering and Computer science ERC-NBS ISRC ASRI Seoul National University San 56-1 Shinlim-dong Kwanak-ku Seoul 151-742 Korea Now with Samsung Advanced Institute of Technology. Now with Samsung Electronics Co. Ltd.

Etching with (111) silicon is relatively new, but it represents very exciting opportunities in micro and nano system applications. By combining wet and dry anisotropic etching, high-precision, actuatable micro and nano structures can be fabricated in single-crystalline silicon. This paper reviews several relevant (111) microfabrication results reported in the literature. Among these, a single-mask process that we call sacrificial bulk micromachining (SBM) is reviewed in detail. Various electrical isolation methods as well as a number of applications to micro and nano systems are presented.

关键词： Micro and nano systmes SBM process (111) silicon

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A new isolation method for single crystal silicon MEMS and its application to z-axis microgyroscope

A new isolation method for single crystal silicon MEMS and i...

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International Electron Devices Meeting (IEDM)

作者： Sangjun Park Jongpal Kim Donghun Kwak Hyoungho Ko W. Carr J. Buss Dong-il Cho School of Electrical Engineering and Computer Science ERC-NBS ASRI ISRC Seoul National University Seoul South Korea New Jersey Microsystem Inc. Newark NJ USA Office of Naval Research Arlington VA USA

This paper presents a new method for electrically isolating the released high-aspect ratio single crystal silicon MEMS structures. In this method, horizontal dielectric layers are implanted at arbitrary depths in any desired region of a wafer, using the Sacrificial Bulk Micromachining (SBM) process. A z-axis microgyroscope is fabricated by the proposed method. The measured noise-equivalent angular rate resolution is 0.0074/spl deg//sec, the input range is larger than /spl plusmn/ 50/spl deg//sec, and the measured bandwidth is 7.3 Hz. The proposed method achieves electrical isolation with excellent mechanical stability, and is free from the footing phenomenon.

关键词： Silicon Micromechanical devices Etching Dielectrics Micromachining Application software Mechanical variables measurement Electric variables measurement Noise measurement Electrodes

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Robust delay estimation for internet multimedia applications

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Joint International Workshops on Interactive Distributed Multimedia Systems and Protocols for Multimedia Systems, IDMS/PROMS 2002

作者： Park, Kyung-Joon Jeon, Won Jong Nahrstedt, Klara BĄSar, Tamer Choi, Chong-Ho School of Electrical Engineering and Computer Science and ASRI Seoul National University Seoul151-742 Korea Republic of Department of Computer Science University of Illinois at Urbana-Champaign IL United States Department of Electrical and Computer Engineering and Coordinated Science Laboratory University of Illinois at Urbana-Champaign IL United States

ISBN: (纸本)9783540001690

Traffic estimation and modeling has been a crucial issue in many research areas of communication networks. For example, intermediate routers in networks estimate the rate of packet flows via queue size information in order to maximize throughput and provide fairness between flows. Also, many senders in the end system such as multimedia applications estimate end-to-end delay between a sender and a receiver to reduce dropping probability of packet. In this position paper, we propose a robust adaptive estimation scheme for Internet multimedia applications. The proposed scheme adopts an autoregressive (AR) model for the process and identifies the parameters of the AR process via a robust identification algorithm. This robust identification algorithm usually leads to better performance when the noise is correlated and/or nonstationary, and it is also more robust to modeling uncertainties. Here, we consider the problem of end-to-end delay estimation for audio playout mechanisms. We rigorously formulate the proposed scheme in the realm of audio playout mechanisms and give some preliminary simulation result which shows effectiveness of the proposed scheme. Even though we apply the proposed scheme to the estimation of end-to-end delay in audio applications, the scheme itself is very general and we expect that it can be applied to many other estimation problems in Internet multimedia applications. ©Springer-Verlag Berlin Heidelberg 2002

关键词： Uncertainty analysis

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Search space reduction in ordinal optimization for performance evaluation of DEDS

Search space reduction in ordinal optimization for performan...

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IEEE Conference on Decision and Control

作者： Kyung-Joon Park Chong-Ho Choi School of Electrical Engineering & Computer Science and ASRI Seoul National University Seoul South Korea

ISBN: (纸本)0780370619

Simulation plays a vital role in analyzing DEDS. However, using simulation to analyze complex systems can be time-consuming and expensive. Particularly, in the case of precise performance evaluation, computing budget, time constraint, and pseudo-random number generator limitations can become prohibitive. Ordinal optimization is an effective approach for improving the efficiency of simulation and optimization of DEDS. However, the ordinal optimization approach does not pay much attention to the problem of large search space. In the paper, for the reduction of search space, we propose a combined approach, ordinal optimization with orthogonal arrays. With this approach, the problem of large search space in stochastic optimization can become more manageable. Consequently, the proposed method can be more efficient for the reduction of simulation burden compared to the conventional ordinal optimization method.

关键词： Computational modeling computer simulation Analytical models Performance analysis Time factors Stochastic processes System performance Optimization methods Calculus Differential equations

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Logical evolution method for learning Boolean functions

Logical evolution method for learning Boolean functions

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IEEE International Conference on Systems, Man and Cybernetics

作者： Myoung Soo Park Jin Young Choi School of Electrical Engineering & Computer Science ASRI Seoul National University Seoul South Korea

In this paper, we present a new learning algorithm, referred to as the logical evolution (LE) method. To learn a Boolean function, the LE method uses not only new information in the given training examples but also old information learned in the past. By using only one network to learn many functions, old information can be re-used for learning new problems efficiently. In this paper, we present the network structure and the learning algorithm of LE and analyse its properties. Its learning capability is also shown by means of two experiments.

关键词： Boolean functions Algorithm design and analysis Decision trees Neural networks Induction generators computer science Learning systems Tree data structures

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Nonlinear adaptive guidance considering target uncertainties and control loop dynamics

Nonlinear adaptive guidance considering target uncertainties...

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American Control Conference (ACC)

作者： Jin Young Choi DongKyoung Chwa Heum-Pil Cho School of Electrical Engineering ASRI Seoul National University Seoul South Korea Electrical and Computer Engineering University of Texas Austin Austin USA

Proposes a nonlinear adaptive guidance law. The fourth order state equation for an integrated guidance and control loop is formulated considering target uncertainties and control loop dynamics. The state equation is further changed into the normal form by nonlinear coordinate transformation. A nonlinear adaptive guidance law is proposed to compensate the uncertainties in both target acceleration and control loop dynamics. The proposed law adopts the sliding mode control approach with adaptation for unknown bound of uncertainties. The present approach can effectively solve the existing guidance problem against target maneuver and the limited performance of the control loop. We provide stability analyses and demonstrate the effectiveness of our scheme through simulations.

关键词： Adaptive control Programmable control Uncertainty Sliding mode control Nonlinear equations Acceleration Missiles Navigation Control systems Stability analysis

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A robust control for engine and transmission systems: Enhancement of shift quality

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JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing 2001年第3期44卷 697-707页

作者： Yang, Kyung-Jinn Hong, Keum-Shik Cho, Dong-Il Department of Mechanical and Intelligent Systems Engineering Graduate College Pusan National University 30 Changjeon-dong Kumjeong-ku Pusan 609-735 Korea Republic of School of Mechanical Engineering Pusan National University 30 Changjeon-dong Kumjeong-ku Pusan 609-735 Korea Republic of School of Electrical Engineering and Computer Engineering ASRI Seoul National University San 56-1 Shinlim-dong Kwanak-ku Seoul 151-742 Korea Republic of

In this paper, a robust integrated control for engine and automatic transmission systems is investigated. The modeling of powertrain system is split into five subparts including an engine, a torque converter, an automatic transmission, clutch torque generation, and a drivetrain. For improving the ride quality, a two-stage control strategy, torque phase and inertia phase, is proposed. During the torque phase, the slip in first gear is maintained to near zero, while the reaction carrier speed and turbine speed during the inertia phase are controlled to track their desired speeds. The reaction carrier speed is adjusted by the second clutch torque, and the turbine speed is controlled by engine throttle angle and spark advance. Due to the uncertainty and unmodelled dynamics of the system, the uniform ultimate boundedness of the error signals is assured by applying the Lyapunov stability analysis. Simulation results are provided.

关键词： Robustness (control systems)

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Static anti-reset windup method for saturating control systems with multiple controllers and multiloop configuration

Static anti-reset windup method for saturating control syste...

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American Control Conference (ACC)

作者： Jong-Koo Park Chong-Ho Choi School of Electrical & Computer Engineering Sung Kyun Kwan University Suwon South Korea School of Electrical Engineering ASRI and ERC-ACI by KOSEF Seoul National University South Korea

ISBN: (纸本)0780338324

Presents an anti-reset windup (ARW) compensation method for saturating control systems with multiple controllers and/or multiloop configuration. The proposed ARW method is motivated by the concept of equilibrium point. The design parameters of the ARW scheme is derived explicitly by minimizing a reasonable performance index. In the event of saturation, the resulting dynamics of the compensated controller reflects the dynamics of a linear closed-loop system. The proposed method guarantees the total stability of resulting control systems under a certain condition.

关键词： Control systems Windup Stability Performance analysis Process control Process design Design methodology Control nonlinearities Linear systems Degradation

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Dynamical anti-reset windup method for saturating control systems with multiple controllers and multiloop configuration

Dynamical anti-reset windup method for saturating control sy...

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IEEE Conference on Decision and Control

作者： Jong-Koo Park Chong-Ho Choi School of Electrical & Computer Engineering Sung Kyun Kwan University Suwon South Korea School of ElectricalEngineering ASRI and ERC-ACI by KOSEF Seoul National University South Korea

ISBN: (纸本)0780341872

Presents a dynamical anti-reset windup (ARW) compensation method for saturating control systems with multiple controllers and/or multiloop configuration. By regarding the difference of controller states in the absence and presence of saturating actuators as an objective function, the dynamical compensator which minimizes the objective function is derived in an integrated fashion. The proposed dynamical compensator is a closed form of the plant and controller parameters. The resulting dynamics of the compensated controller reflects the linear closed-loop system. The proposed method guarantees the total stability of the resulting system. The effectiveness of the proposed method is illustrated by applying it to a servo motor control system.

关键词： Control systems Windup Actuators Stability Servomechanisms Motor drives Nonlinear control systems Control nonlinearities System performance Process control

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