• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.325-330
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• 2018

In this paper, we investigated the impedance method for searching fault detection point in case of an accident in the AC electric railway AT feeding system. For this purpose, simulation circuit modeling and prototype hardware are made based on the known numerical analysis. As a result of simulation modeling of the feeding system based on the numerical analysis of the impedance method confirmed that the modeling was properly implemented with an average error rate of 0.07%. Also, as a result of fault event by hardware simulator, it was confirmed that the breaker operation time is shortened and the fault current is decreased while the voltage is close to the supply voltage in the transient state as the point of the fault accident moves away from the substation(SS).

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1487-1496
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• 2013

In this paper, a novel algorithm for PD localization in power transformers based on wavelet de-noising technique and energy criterion is proposed. Partial discharge is one of the main failures in power transformers. The localization of which could be very useful for maintenance systems. Acoustic signals due to a PD event are transient, irregular and non-repetitive. So wavelet transform is an efficient tool for this signal processing problem that gives a time-frequency demonstration. First, different wavelet based de-noising methods are analyzed. Then, a reasonable structure for threshold value determining and applying manner on signals is presented. Evaluated errors are good evidences for choices. Next, applying the elimination low energy frequency bands is discussed and developed as a de-noising method. Time differences between signals are used for PD localization. Different ways in time arrival detection are introduced and a novel approach in energy criterion method is presented. At the end, the quality of algorithm is verified through the different assays in lab.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.173-176
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• 2009

본 논문에서는 영상 정보와 오디오 정보 분석을 이용하여 TV 골프 방송 프로그램에서 중요 이벤트 구간을 검출하고 요약 하는 알고리즘을 제안한다. 제안하는 알고리즘에서는 입력되는 TV 골프 동영상을 영상 신호와 오디오 신호로 분리한 후에, 연속적인 오디오 스트림을 내용 기반의 오디오 구간으로 분류한 뒤 오디오 이벤트 구간을 검출하고, 이와 병렬적으로 영상정보에서 선수들의 플레이 장면을 검출한다. 플레이 장면 검출에 있어서는 방송 환경이나 날씨 등의 변화하는 다양한 조건에 대해 플레이 장면에 대한 오프라인 모델과 함께 경기 내에서 발생한 온라인 모델에 대한 학습을 혼합 적용함으로써 검출 성능을 높였다. 오디오 신호로부터 관중들의 박수소리와 스윙 사운드를 통해 검출된 오디오 이벤트와 플레이 장면은 이벤트 장면 검출 및 요약본 생성을 위해 사용된다. 제안된 알고리즘은 멀티 모달 정보를 이용하여 이벤트 구간 검출을 수행함으로써 중요 이벤트 구간 검출의 정확도를 높일 수 있었고, 검출된 이벤트 구간에 대한 요약본 생성을 통해 골프 경기를 시청하는 사용자가 원하는 부분을 빠르게 브라우징하여 시청하는 것이 가능하여 높은 사용자 만족도를 얻을 수 있었다.

• Journal of KIISE:Information Networking
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• v.32 no.5
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• pp.574-582
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• 2005

Localization in wireless sensor networks is essential to important network functions such as event detection, geographic routing, and information tracking. Localization is to determine the locations of nodes when node connectivities are given. In this paper, centroid approach known as a distributed algorithm is extended to a centralized algorithm. The centralized algorithm has the advantage of simplicity. but does not have the disadvantage that each unknown node should be in transmission ranges of three fixed nodes at least. The algorithm shows that localization can be formulated to a linear system of equations. We mathematically show that the linear system have a unique solution. The unique solution indicates the locations of unknown nodes are capable of being uniquely determined.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.73-76
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• 2015

최근 스마트 단말을 통한 유해 콘텐츠의 보급이 확산되면서 스마트 단말에서 유해 콘텐츠를 차단하기 위한 소프트웨어의 필요성이 증가하고 있다. 이에 본 논문에서는 안드로이드 기반 스마트 단말에서 실행 이벤트의 분석을 통하여 유해 콘텐츠를 탐지 할 수 있는 방법을 제안한다. 본 논문에서는 안드로이드기반 스마트 단말에서 스트리밍 서비스가 실행되는 구조 및 관련 실행 이벤트들의 연관성을 분석하였으며, 분석 결과를 토대로 스마트 단말에서 유해 콘텐츠의 실행 여부를 판단할 수 있는 소프트웨어를 개발하였다.

• Korean Journal of Adult Nursing
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• v.26 no.5
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• pp.573-583
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• 2014

Purpose: Cardiac arrest has multiple characteristics that need to be approached as an integrated method according to the various changes in the body system. This study was performed to develop a useful guideline for early detection of cardiac arrest by revealing the attributes of cardiac arrest through a concept analysis. Methods: This study was conducted according to the Walker and Avant's concept analysis method. Systematic literature review and in-depth interview with nurses who experienced cardiac arrest situation were conducted. Based on the literature reviews and in-depth interviews with nurses, the attributes and the empirical referents of the concept of cardiac arrest were elicited. Results: The definable attributes of cardiac arrest were 1) loss of consciousness, 2) abnormal respiratory condition, 3) abnormal cardiovascular signs. Cardiac arrest was found to occur by several antecedents such as cardiac problem, non-cardiac problem, or general problem, whereas ischemia and re-perfusion injury, which can lead to multiple organ failure and death, were derived as consequences. Conclusion: In this study, the concept analysis eliciting attributes and empirical referents is found to be useful as a guideline for understanding and managing cardiac arrest. Based on these findings, clinical providers are expected to make a precise and rapid decision on cardiac arrest and respond quickly, which may increase survival rate of the patients underwent the arrest event.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.672-677
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• 2010

Recently, the efficient management system for large-scale sensor data has been required due to the increasing deployment of large-scale sensor networks. In this paper, we propose a cloud-based sensor data management system with low cast, high scalability, and efficiency. Sensor data in sensor networks are transmitted to the cloud through a cloud-gateway. At this point, outlier detection and event processing is performed. Transmitted sensor data are stored in the Hadoop HBase, distributed column-oriented database, and processed in parallel by query processing module designed as the MapReduce model. The proposed system can be work with the application of a variety of platforms, because processed results are provided through REST-based web service.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.95-100
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• 2009

Nowadays there are many studies and there's huge development about USN/RFID which have great developmental potential to many kinds of applications. More and more real time application apply USN/RFID technology to identify data collect and locate objects. Wide deployment of USN/RFID will generate an unprecedented volume of primitive data in a short time. Duplication and redundancy of primitive data will affect real time performance of application. Thus, security applications must filter primitive data and correlate them for complex pattern detection and transform them to events that provide meaningful, actionable information to end application. In this paper, we design a ECA Rule system for security monitoring of exhibition. This system will process USN/RFID primitive data and event and perform data transformation. It's had applied each now in exhibition hall through this study and efficient data transmission and management forecast that is possible.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.248-251
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• 1992

In this paper, the RedMAP, i.e. a redundant Mini-MAP system for high reliability is proposed. Redundancy is implemented for LLC, MAC, and Physical layer of ISL-Mini -MAP. The detection of error of the network, the broadcasting of the error event, and the network change sequence are three major functions for the dualized Mini-MAP system. The abnormal operation of the network is mainly detected indirectly with the function of the TBC( token bus controller). The time delay to be required for the change of the networks must be minimized. With the RedMAP, we can achieve successful transmission only with short additional recovery time.

• Journal of Integrative Natural Science
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• v.8 no.2
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• pp.128-134
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• 2015

This paper focuses on the applicability of a continuous monitoring method on trace sulfur compounds in the ambient air by TD and GC/PFPD. The target compounds for monitoring include H2S(hydrogen sulfide), Methyl mercaptan, Dimethyl Sulfide, and Dimethyl disulfide. The result of QA/QC on monitoring instruments satisfies all the standards of Odor Measurement and Analysis Method, showing that the reproductivity of the compounds by concentration is within 10%, linearity is above 0.98 of a correlation efficient, method detection limit is 0.16 ppb by MM standard, and recovery rate is over 70%. Monitoring was conducted for two years from March 2006 to February 2008. As a result of the monitoring, the average concentration of H2S was 0.08 ppb, with the maximum concentration at 16.15 ppb. The result indicates that it is reasonable to do continuous monitoring as there appears a spontaneous event of high concentration by the condition of the site during monitoring odor-causing substances. Therefore, it is suggested that the continuous monitoring method used in this paper is appropriate to identify the characteristics of sudden occurrence and concentration variations of sulfur compounds.