• 전기전자학회논문지
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• 제20권4호
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• pp.449-453
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• 2016

열악한 자연환경에 무작위로 배포되는 무선센서 네트워크(Wireless Sensor Networks : WSNs)의 센서 노드(node)에서의 고장은 필수적으로 발생하며, 무선센서 네트워크의 설계시 고려되어야 할 핵심과제이다. 본 논문에서는 센서노드에서 발생 가능한 고장모델을 분류하였다. 특히 CH(Cluster Head) 노드에 고장이 발생할 경우 고장을 복구 가능한 새로운 코드방식을 제안하고, 고장 복구 알고리즘을 제시하였다. 제안한 코드 방식은 기존 해밍코드대비 정보길이 16비트 이하에서 동등한 크기의 패리티 비트를 가지며, 코드 발생이 아주 간단한 장점을 가진다. 이것은 전력효율을 높이면서 WSN의 안정성을 유지하는 데 매우 중요하다.

• 전기학회논문지P
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• 제65권1호
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• pp.41-46
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• 2016

It has been proven that the dissolved gas analysis (DGA) is the most effective and convenient method to diagnose the transformers. The DGA is a simple, inexpensive, and non intrusive technique. Among the various diagnosis methods, IEC 60599 has been widely used in transformer in service. But this method cannot offer accurate diagnosis for all the faults. This paper proposes a fault diagnosis method of oil-filled power transformers using IEC code based neuro-fuzzy model. The proposed method proceeds two steps. First, IEC 60599 method is applied to diagnosis. If IEC code can't determine the fault type, neuro-fuzzy model is applied to effectively classify the fault type. To demonstrate the validity of the proposed method, experiment is performed and its results are illustrated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.952-963
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• 2008

The collection of KTX trainset fault code is made by DEP software. We can improve software function and update data after understanding DEP software function and software structure. For the improvement of trainset function and its performance, the same improvement of performance and structure change as DEP software, which collects and analyzes train's fault information, are required. Accordingly, we made a research for functional strucfure of KTX fault code collection software, STR3F, variable declaration through Script.rxr file and code analysis method and proceeded research for realizing more improved user environment of DEL software and fault analysis method.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1306-1313
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• 2018

The randomness and incipient nature of certain faults in reactor systems warrant a robust and dynamic detection mechanism. Existing models and methods for fault diagnosis using different mathematical/statistical inferences lack incipient and novel faults detection capability. To this end, we propose a fault diagnosis method that utilizes the flexibility of data-driven Support Vector Machine (SVM) for component-level fault diagnosis. The technique integrates separately-built, separately-trained, specialized SVM modules capable of component-level fault diagnosis into a coherent intelligent system, with each SVM module monitoring sub-units of the reactor coolant system. To evaluate the model, marginal faults selected from the failure mode and effect analysis (FMEA) are simulated in the steam generator and pressure boundary of the Chinese CNP300 PWR (Qinshan I NPP) reactor coolant system, using a best-estimate thermal-hydraulic code, RELAP5/SCDAP Mod4.0. Multiclass SVM model is trained with component level parameters that represent the steady state and selected faults in the components. For optimization purposes, we considered and compared the performances of different multiclass models in MATLAB, using different coding matrices, as well as different kernel functions on the representative data derived from the simulation of Qinshan I NPP. An optimum predictive model - the Error Correcting Output Code (ECOC) with TenaryComplete coding matrix - was obtained from experiments, and utilized to diagnose the incipient faults. Some of the important diagnostic results and heuristic model evaluation methods are presented in this paper.

• 한국공간정보시스템학회 논문지
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• 제11권2호
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• pp.13-18
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• 2009

This paper presents the implementation procedure of encoding and decoding algorithms for Tornado code that can provide fault tolerance for storage and transmission system. The degree distribution satisfying heavy tail distribution is produced. Based on this distribution, a good random irregular bipartite graph is attained after plenty of trails. Such graph construction is proved to be efficient, and the experiments also demonstrate that the implementation obtains good performance in terms of decoding overhead.

• 한국초전도ㆍ저온공학회논문지
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• 제14권4호
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• pp.36-40
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• 2012

This paper presents an experimental and numerical study on current limiting characteristics of a fault current controller (FCC). The FCC consists of an AC/DC power converter, a superconducting coil, and a control unit. Even though some previous researches proved that the FCC could adjust the fault current level, the current limiting characteristics by the superconducting coil should be investigated for design of the coil. In this paper, four kinds of model coils were tested; 1) air core, 2) iron core without any bias, 3) reversely magnetized core (RMC) using permanent magnets, and 4) RMC using an electromagnet. Based on a comparative study, it is confirmed that a RMC by an electromagnet (EM) could increase the effective inductance of the coil. In this paper, a numerical code to simulate the HTS coil with RMC was developed. This code can be applied to design the HTS coil with active reversely magnetized bias coil.

• 문화기술의 융합
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• 제4권3호
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• pp.221-226
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• 2018

특수목적 차량은 일반적으로 사용자의 요구에 따라 주문 제작된다. 이러한 차량들이 고장을 일으키는 경우에는 수리비용 및 시간이 많이 든다. 이러한 문제점들을 해결하고자 차량의 이상여부를 원격으로 점검하고 고장부위를 원격에서 파악하여 수리비용 및 수리 기간을 단축하고자 한다. 본 연구에서는 전기제어부의 고장부위를 자동으로 판별하고 이를 사용자의 휴대폰앱을 통하여 바로 파악하여 즉각적인 고장코드를 특장차 제조사측에 통보하여 고장수리를 빠르고 원활하게 하고자 한다. 이를 구현하기 위하여 IoT 사물인터넷의 기술을 이용하여 특수목적의 차량 분야의 현장에서 요구되는 항목에 따라 고장부위를 스스로 판단하고 기기 자체적으로 제작사측에 고장여부를 알려주는 시스템을 구축하고자 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1255-1261
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• 2010

An operating information and fault recode of train is very important information for safety driving and maintenance. And these information is increased and need high speed as the number of trains is increased. Wireless LAN or CDMA network is efficient to report more complicated and various information from vehicle to server in control center. Existing wireless transmission system has weakness due to transmission system is separated with TDCS and standalone. At first, standalone system needs space to be installed and cost is increased. And data transmission capacity and speed is limited by complicated structure that transmission system receive data thru serial communication like RS232 and then data transmission system send data to server in control center. This article is study to develop embedded & wireless fault code transmission device to be installed in TDCS to overcome weakness of space and to have more cost effective and simple structure. It is adapted 802.11b/g WiFi for wireless communication and OS is used embedded Linux that can easily implement wireless communication environment and ensure TCP/IP communication’s security. We also implement simple server to test wireless communication between embedded & wireless fault code transmission device and server in control center.

• 신재생에너지
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• 제9권2호
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• pp.51-57
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• 2013

The Grid code is being strengthen as increase of renewable energy ratio. Especially, the grid connection regulations are continuously being updated for stable operation of power grids. Static grid support and Dynamic grid support must make an accurate measure at Grid connected point because they needs control algorithm individually. It has to exactly measure voltage including switching ripple at the output of the inverter generating system. In addition, it is necessary to have an accurate voltage measurement when the situation rapidly changing the grid impedance is caused by the input of serial impedance of transformer and line impedance as well as Grid Fault Device. In this paper, We propose a new detection method of grid voltage to calculate accurately the r.m.s voltage of the grid connection point along the standard required by the low voltage regulation. We verified performance through simulation grid fault device.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1239-1243
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• 2005

A multipath mitigation method using the fault detection and isolation technique is proposed for the CDGPS. The base station is assumed to be immune to the effect of the multipath. With this reasonable assumption, the effect of multipath in moving station is mitigated. For that, the double difference measurement is produced, and then another additional difference between code pseudorange and acclumulated carrier phase is calculated. The test statistic is constituted with those differences. The hypothesis testing is applied to that test statistic. The proposed test statistic makes use of the effect of multipath in code pseudoranges and it does not use time differences. Therefore the detection ability for multipath is improved in most environments. However, the increased number of differences makes the measurement noises larger. The performance of the method is compared with that of the conventional parity space method with code pseudorange.