• 전자공학회논문지S
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• 제35S권2호
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• pp.70-78
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• 1998

Spike detection in long-term EEG monitoring forepilepsy by wavelet transform(WT), artificial neural network(ANN) and the expert system is presented. First, a small set of wavelet coefficients is used to represent the characteristics of a singlechannel epileptic spikes and normal activities. In this stage, two parameters are also extracted from the relation between EEG activities before the spike event and EEG activities with the spike. then, three-layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained from the first stage. Spikes are identified in individual EEG channels by 16 identical neural networks. Finally, 16-channel expert system based on the context information of adjacent channels is introducedto yield more reliable results and reject artifacts. In this study, epileptic spikes and normal activities are selected from 32 patient's EEG in consensus among experts. The result showed that the WT reduced data input size and the preprocessed ANN had more accuracy than that of ANN with the same input size of raw data. Ina clinical test, our expert rule system was capable of rejecting artifacts commonly found in EEG recodings.

• 한국게임학회 논문지
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• 제2권1호
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• pp.77-83
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• 2002

의료분야에 게임이 적용되는 사례가 늘고 있다. 본 게임은 게임을 즐기는 사용자의 심박동의 미세한 변화(HRV:heart rate variability)를 파형분석하여 MP(mental stress)와 PH(physical stress) 상태를 모니터링한 후 호흡(respiration)의 조절을 통해 자율신경체계의 질병을 예방하기 위한 목적으로 개발되었다. 기존의 지속적인 반복작용을 통한 단순한 트레이닝이 아닌 게임고유의 특징인 상호작용성(interaction)을 높여 사용자가 지루함이나 거부감을 느끼지 않고 접근이 용이한 스트레스이완프로그램(SRP:stress relaxation program)이라는데 의미가 있다.

• Journal of Mechanical Science and Technology
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• 제17권10호
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• pp.1411-1422
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• 2003

The detection of free spaces between obstacles in a scene is a prerequisite for navigation of a mobile robot. Especially for stereo vision-based navigation, the problem of correspondence between two images is well known to be of crucial importance. This paper describes multi-range approach of area-based stereo matching for grid mapping and visual navigation in uncertain environment. Camera calibration parameters are optimized by evolutionary algorithm for successful stereo matching. To obtain reliable disparity information from both images, stereo images are to be decomposed into three pairs of images with different resolution based on measurement of disparities. The advantage of multi-range approach is that we can get more reliable disparity in each defined range because disparities from high resolution image are used for farther object a while disparities from low resolution images are used for close objects. The reliable disparity map is combined through post-processing for rejecting incorrect disparity information from each disparity map. The real distance from a disparity image is converted into an occupancy grid representation of a mobile robot. We have investigated the possibility of multi-range approach for the detection of obstacles and visual mapping through various experiments.

• 한국생산제조학회지
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• 제21권4호
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• pp.651-657
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• 2012

In many control fields high position performance is essentially required in reducing the over-shoot phenomena which is produced by improving the quick response in starting and in minimizing the variation of the response characteristic on disturbance and load variation In this paper, the design method for a position control is suggested for constructing the PI-PD controllers by using an internal PD feedback loop in PI and PD control system. Applying this method to the position control system used a DC servo motor as a driver, the transfer PI and PD controllers are designed simultaneously and the coefficients of these controllers are determined by using the transfer function of a plant and a proportional coefficient from mathematical technique. From the result of computer simulation in PI-PD control system by applying this control technique, we can verify the usefulness of this method in rejecting of over-shoot of starting, compensating of response variation on the load variation, and shorting the settling time.

• 한국정보통신학회논문지
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• 제4권3호
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• pp.619-625
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• 2000

많은 제어기법들이 이산시간영역제어계의 제어성능을 개선시키기 위해서 제안되고 있다. 위치제어계에서 일반적으로 제어기의 출력이 제어대상의 입력으로 사용된다. 그러나 불필요한 잡음이 제어기의 출력에 포함된다. 그러므로 이러한 잡음을 제거하기 위해서 전치보상기를 사용할 필요가 있다. 본 논문에서 전치보상기를 갖는 확대 I-PD 제어계를 구성하였고 이 전치보상기와 I-PD 제어기를 신경망으로 설계하였다. 그리고 전치보상기와 I-PD제어기의 계수들이 계의 응답특성들이 어떤 조건 하에서 변할 때 계의 희망하는 응답이 되도록 자동적으로 조정되도록 하였다.

• 전기학회논문지
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• 제56권1호
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• pp.214-221
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• 2007

This paper presents a myoelectric hand prosthesis(MHP) with two degree of freedom(2-DOF), which consists of a mechanical hand, a surface myoelectric sensor(SMES) for measuring myoelectric signal, a control system and a charging battery. The actuation for the 2-DOF hand functions such as grasping and wrist rotation was performed by two DC-motors, and controlled by myoelectric signal measured from the residual forearm muscle. The grip force of the MHP was automatically changed by a mechanical automatic speed reducer mounted on the hand. The skin interface of SMES was composed of the electrodes using the SUS440 metal in order to endure a wet condition due to the sweat. The sensor was embedded with a amplifier and a filter circuit for rejecting the offset voltage caused by power line noises. The control system was composed of the grip force sensor, the slip sensor, and the two controllers. The two controllers were made of a RISC-type microprocessor, and its software was executed on a real-time kernel. The control system used Force Sensing Resistors, FSR, as slip pick-ups at the fingertip of a thumb and the grip force information was obtained from a strain-gauge on the lever of the MHP. The experimental results were showed that the proposed control system is feasible for the MHP.

• 한국항공운항학회지
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• 제18권3호
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• pp.77-83
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• 2010

"The prohibition of careless or reckless flight" is the regulation specified not only in the national air law but ICAO ANNEX and FAR. This article(item) has not been categorized properly unlike other items and the question such as why this is described as a fundamental and essential act can be answered only by the party subjected to administrative measures in case of Korea and this kind of violation is so rare that it is not easy to understand the legal meaning and the function of the term, "The prohibition of careless or reckless flight" In case of U.S where aviation cases are common, the distinction between the term "careless" or "reckless" operation depends on whether to recognize the given situation. Some incidents happened by failing to aware NOTAM, violating ATC, or T/W landing where a pilot did not recognize the violation itself are considered to be "Careless" flight. Others such as low altitude high speed flight, approximate flight, Rejecting ATC instruction where a pilot intends to or is remiss in safety are regarded as "Reckless" flight. For pilots who are required to take the highest level of care from preparing for flight to stopping engines or completely disembarking passengers from a plane, the clear understanding of the most basic concept of "careless" or "reckless" flight should be emphasized for the safe flight and it is the time for the authorities to set a standard for proper measures by definite legal interpretations.

• The Journal of Asian Finance, Economics and Business
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• 제7권3호
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• pp.127-135
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• 2020

The paper aims to examine whether business cycles affect the link between financial development and bank risk, measured by Zscore and non-performing loans to total loans in six Southeast Asian countries, namely Indonesia, Philippines, Malaysia, Singapore, Thailand and Vietnam. This study uses a sample of 95 listed commercial banks over a 15-year period between 2004 and 2018 in the six Southeast Asian countries. This study employs panel OLS regression and modifications to tackle issues such as endogeneity and heteroscedasticity. The results show that the impact of stock market development (the ratio of the market capitalization to GDP) on Zscore is significantly positive, whereas its effect on non-performing loans is significantly negative. The findings suggest that financial development, in terms of stock market capitalization, improves banks' Zscores and reduces their level of non-performing loans, suggesting that financial development on average reduces bank risk. The impact of business cycle is insignificant towards bank risk, thus rejecting both counter- and pro-cyclical hypotheses, except for the case of risk indicator of loan loss provisions. Examining the joint effect of the business cycle and financial development on bank risk, we find that the phase of business cycles generally does not moderate the link between financial development and bank risk.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.358-361
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• 1997

This paper describes a multichannel epileptic seizure detection algorithm based on wavelet transform(WT), artificial neural network(ANN) and expert system. First, through the WT, a small number of wavelet coefficients is used to represent the single channel epileptic spike. Next, 3-layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained above. Finally, 16 channel expert system which is based on clinical experience is introduced as a artifact rejection and reliable detection. The suggested algorithm was implemented on personal computer(PC). Two main events i.e., epileptiform and normal activities, were selected from 32 person's EEGs(normal: 20, seizure disorder: 12) in consensus among experts. The result was that WT reduced data input size and ANN detected 97 of the 100 EEGs containing definite spike - sensitivity of 97%. Expert rule system was capable of rejecting a wide variety of artifacts commonly found in EEG recordings. It also reduced false positive detections of ANN.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2087-2092
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• 2005

Using disturbance observer (DOB) is effective in enhancing the performance of dynamic system in the presence of disturbances. Recently the definition of disturbance has been expanded to modeling uncertainty including parameter variation, internal disturbance. Various structures of DOB have been proposed to improve sensitivity of system for better disturbance rejection performance. However in the case of improvement of sensitivity function, it tends to bring poor transient response due to cross-coupling and phase lag. Furthermore it could be very sensitive to measurement noise due to increased peak of complementary sensitivity function. In this paper, a dual disturbance observer (Dual-DOB) is proposed to reduce the effect of such cross-coupling. It is possible for us to improve the sensitivity function with additional external DOB with hardly affecting complementary sensitivity function. Thus it is able to have robustness against measurement noise. Since we are able to design DOBs of internal and external loop independently, we could prevent transient response quality from degrading while improving the sensitivity function. The proposed Dual-DOB is applied to a commercial optical disk drive tracking servo system. The experimental result shows that the Dual-DOB is an effective method in rejecting the disturbance as well as improving the tracking performance.