• Journal of IKEEE
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• v.20 no.4
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• pp.449-453
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• 2016

Failures would occur because of the hostile nature environment in Wireless Sensor Networks (WSNs) which is deployed randomly. Therefore, considering faults in WSNs is essential when we design WSN. This paper classified fault model in the sensor node. Especially, this paper proposed new error correcting code scheme and fault recovery algorithm in the CH(Cluster Head) node. For the range of the small size information (<16), the parity size of the proposed code scheme has the same parity length compared with the Hamming code, and it has a benefit to generate code word very simple way. This is very essential to maintain reliability in WSN with increase power efficiency.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.1
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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.

• Proceedings of the KSR Conference
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• 2008.06a
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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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• v.50 no.8
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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.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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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.

• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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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.

• The Journal of the Convergence on Culture Technology
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• v.4 no.3
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• pp.221-226
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• 2018

Special-purposed vehicles are customized according to the user's requirements. When these vehicles are out of oder, they are costly and time consuming to repair. In order to solve these problems, we want to remotely check whether the vehicle is abnormal and remotely identify the fault area, thereby shortening the repair cost and the repair period. In this study, the faulty part of the electric control part is automatically identified, and it is immediately grasped through the user's mobile phone application and an instant fault code is notified to the car manufacturer for quick and smooth fault repair. In order to realize this, we want to build a system that uses the technology of IoT to determine the fault area according to the items required in the field of the special purpose vehicle and notify the manufacturer of the fault on its own.

• Proceedings of the KSR Conference
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• 2010.06a
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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.

• New & Renewable Energy
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• v.9 no.2
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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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• 2005.06a
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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.