• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.616-624
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• 2015

Flashover of power transmission line insulators due to contamination is a major threat to the reliable operation of power system. This paper deals with the analysis of leakage current characteristics of polymeric insulator using S-Transform technique in order to develop a better diagnostic tool to identify the surface condition of outdoor polymeric insulators. In this work, experiments were carried out on 11 kV silicone rubber insulator under AC voltage at different pollution levels. Moving average technique was adopted to find the trend followed by LC peak at different relative humidity conditions. S-Transform was used to find the relationship between energy and frequency content of the leakage current signal with respect to increase in pollution level over a period of time. From the S-Transform time-frequency contour analysis, point of transition to severe arcing due to increase in pollution and its thershold limit were evaluated. Reported results show that the surface condition of insulators could be easily identified from the S-Transform time-frequency analysis of leakage current signals.

• 한국시스템다이내믹스연구
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• 제10권2호
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• pp.53-79
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• 2009

The main purpose of this study is to find what steps are needed for a system for CO2 emissions trading to be formulated as government policy, using System Thinking approach. First, this paper analyzed Korean newspapers to consider the social issue regarding CO2 emissions trading. There were more articles related to international issues than domestic ones before 2008. This trend, however, became reversed from January 2008, which means that consideration of CO2 emissions trading has been discussed as a domestic social issue from 2008. Second, it analyzed speeches by former president Roh Moo-Hyun and current president Lee Myung-bak. In particularly, President Lee Myung-bak declared "Low Carbon and Green Growth" as a new growth engine and a Korea's vision of the future national development. Third, it examined which government agencies, including departments and committees, are pursuing policies regarding climate change, global warming, and CO2 emissions trading. Most policy has originated in the Ministry of Environment, although policy alternatives have been proposed in other agencies including the Ministry of Knowledge Economy. The study concludes that the political consideration has played a major role in the policy agenda-setting process of the CO2 emissions trading in Korea.

• 대한의용생체공학회:의공학회지
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• 제35권6호
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• pp.219-226
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• 2014

This study is to develop a basic life support (BLS) app using the android based smartphone and to evaluate the function of the app. Suggested app contains chest compression feedback function, the map of automated external defibrillator (AED), direct emergency call and the basic knowledge of BLS. Using the accelerometer of the smartphone, we implemented a real-time algorithm that estimates the chest compression depth and rate for high quality cardiopulmonary resuscitation (CPR). The accuracy of algorithm was evaluated by manikin experiment. We made contents which were easy to learn the BLS for the layperson and implemented a function that provides the AED location information based on the user's current location. From the manikin experiment, the chest compression depth and rate were no significant differences between the manikin data and the app's feedback data (p > 0.05). Developed BLS app was uploaded on Google Play Store and it was free to download. We expected that this app is useful to learn the BLS for the layperson.

• 한국통신학회논문지
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• 제18권8호
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• pp.1213-1225
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• 1993

하이퍼미디어 시스템은 멀티미디어 정보를 검색하고 제시하기 위하여 링크를 이용한 브라우징과 탐색항해 도구를 이용한다. 본 연구에서 설계·구현한 시스템은 보다 효율적인 탐색항해를 지원하기 위하여 계층적 그룹과 지역 맵 도구를 제공한다. 특히, 클러스터링 기법을 적용하여 클러스터 트리를 형성하고 이를 이용하여 항해시 필요한 지식을 제공하는 방법을 제 안하고 있다. 또한 탐색 과 브라우징 기능을 통합함으로써 하이퍼미디어 시스템의 정보검색기능과 사용자 인터페이스를 높이도록 설계하였다. 본 하이퍼미디어시스템을 백과사전, 참고문헌정보, 전자사전, 전자책등의 분야에 적용할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.398-403
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• 1993

A rule based fuzzy expert system to self-tune PID controllers is proposed in this paper. The proposed expert system contains two rule bases, where one is responsible for "Long term tuning" and the other for "Incremental tuning". The rule for "Long term tuning" are extracted from the Wills'map and the knowledge about the implicit relations between PID gains and important long term features of the output response such as overshoot, damping and rise time, etc., while 'Incremental tuning" rules are obtained from the relations between PID gains and short term features, error and change in error. In the PID control environment, the proposed expert system operates in two phases sequentially. In the first phase, the long term tuning is performed until long term features meet their desired values approximately. Then the incremental tuning tarts with PID gains provided by the long term tuning procedure. It is noticeable that the final PID gains obtained in the incremental tuning phase are only the temporal ones. Simulation results show that the proposed rule base for "Long term tuning" provides superior control performance to that of Litt and that further improvement of control performance is obtained by the "Incremental tuning'.ance is obtained by the "Incremental tuning'.ing'.

• 한방재활의학과학회지
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• 제24권4호
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• pp.111-116
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• 2014

Objectives The purpose of this study is to analyze research trends on the Korean medical treatment of wrist ganglion and to develop the way of treatment. Methods We searched the papers with a key word of 'wrist ganglion' in Korean database (NDSL, KISS, Korean traditional knowledge portal) and Pubmed. Results Total 5 studies were found. Major treatment method was the acupuncture including electroacupuncture, pharmacopuncture and acupotomy. Minor treatments were moxibustion, wet cupping, herbal medicine and percutaneous aspiration. Conclusions Various treatment methods were used for curing wrist ganglion and they were effective. To map out the systemic treatment of Korean medicine on wrist ganglion, more clinical reports are needed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1477-1491
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• 2017

Inspired by the multi-scale nature of hippocampal place cells, a biologically inspired model based on a multi-scale spatial representation for goal-directed navigation is proposed in order to achieve robotic spatial cognition and autonomous navigation. First, a map of the place cells is constructed in different scales, which is used for encoding the spatial environment. Then, the firing rate of the place cells in each layer is calculated by the Gaussian function as the input of the Q-learning process. The robot decides on its next direction for movement through several candidate actions according to the rules of action selection. After several training trials, the robot can accumulate experiential knowledge and thus learn an appropriate navigation policy to find its goal. The results in simulation show that, in contrast to the other two methods(G-Q, S-Q), the multi-scale model presented in this paper is not only in line with the multi-scale nature of place cells, but also has a faster learning potential to find the optimized path to the goal. Additionally, this method also has a good ability to complete the goal-directed navigation task in large space and in the environments with obstacles.

• 한국전자통신학회논문지
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• 제8권2호
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• pp.249-253
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• 2013

본 논문에서는 그린 IT 분야에 대한 특허 정보를 이용하여 분야별 기술 경쟁력 분석과 분야에 적용되는 기술의 다양성 및 분야간 유사도를 분석하였다. 이를 위해 그린 IT를 전기 전자기들의 에너지소모량의 절감 및 IT기술을 기반으로 전력 소비를 줄이는 친환경적인 기술을 개발하는 분야로 범위를 한정하여, 절전기기 및 시스템, 조명제어시스템, 스마트 전력관리시스템, 클라우드 컴퓨팅, 그린하우스/에코시스템으로 한정하여 특허 분석을 수행하였다. 그 결과 절전기기 및 시스템 분야의 기술개발이 가장 활발히 이루어지고 있는 것으로 나타났다. 기술분야 간 기술적 유사도의 경우, 절전기기 제어 및 시스템분야와 클라우드 컴퓨팅 분야와 기술적으로 유사한 것으로 나타났으며, 조명제어시스템과 그린하우스/에코시스템 및 스마트 전력 관리 시스템이 기술적으로 유사한 것으로 분석되었다.

• 정보처리학회논문지B
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• 제13B권1호
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• pp.1-6
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• 2006

단백질의 기능 예측 모델은 guilt-by-association 개념을 바탕으로 단백질-단백질 상호작용 맵을 이용하고 있다. 이 방법은 목표 단백질이 기능이 알려진 단백질과 상호작용이 없는 경우 기능 예측이 불가능하다. 본 논문에서는 단백질 기능 예측 모델을 K-class 다중 분류 문제로 재 정의하고 단백질-단백질 상호작용 데이터 및 단백질의 알려진 속성 등을 학습 모델에 이용한 단위신경망의 설계와 응용을 제안한다. 제안하는 모델은 Yeast 단백질 데이터의 기능 예측에서 단백질-단백질 상호작용 데이터를 이용하는 방법에 비해 분류 예측율에서 우수한 성능을 보였으며 또한 상호작용이 밝혀지지 않은 단백질의 기능 예측을 할 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.853-858
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• 2001

The knowledge of flame structure is essential for control of combustion instability phenomena. Some results of an experimental study on mechanism of naturally occurring combustion oscillations with a single dominant frequency are presented. Tests were conducted in a laboratory-scale dump combustor at atmospheric pressure. Sound level meter was used to track the pressure wave inside the combustor. The observed instability was a longitudinal mode with a frequency of $\sim341.8Hz$. Instability map was obtained at the condition of inlet temperature of $360^{\circ}C$, mean velocities of $8.5\sim10.8m/s$ and well premixed mixture. It showed that combustion instability was susceptible to occur in the lean conditions. In this study, unstable flame was observed from stoichiometric to 0.7 in overall equivalence ratio. At selected unstable conditions, phase-resolved OH chemiluminescence images were captured to investigate flame structure with various mean velocities. As mean velocity is increased, the flame grows and global heat release was changed. Due to these effects, combustion instability can be maintained at more lean air-fuel ratio. Also, these results give an insight to the controlling mechanism for an increasing heat release at maximum pressure.