• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1075-1076
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• 2006

The wide spread of DC electric railway systems such as urban rapid transits including heavy rail and light rail transits has significant ramification as the stray currents from return conductor rails can cause the electrochemical interference, that is, the electrolytic corrosion of both rails and outside underground metallic infrastructures. The immature understanding of either the railway authority who is responsible for establishing the necessary provisions at the design stage or the affected parties makes it difficult to prepare the optimum range of solutions for the long-pending interference problem. In advanced countries, however, numerous assessment studies have been carried out on the stray current interference, by which protective standards and regulations are provided under the collaboration and agreement of the related parties. In this paper, we introduce a european standard from IEC, namely, "IEC 62128-2:2003 railway applications-fixed installations -part 2: protective provisions against the effects of stray currents caused by d.c. traction systems" and a "Code of Practice" produced by Victorian electrolysis committee (VEC) based on "Electricity Safety Act 1998" and "Electricity safety (stray current corrosion) regulations 1999" of Victoria state, Australia.

• Proceedings of the Safety Management and Science Conference
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• 2013.11a
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• pp.615-623
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• 2013

오늘날 기술의 발전으로 시스템들은 점차 대형화 복잡화 되어가고 있다. 이처럼 점차 대형화 복잡화 되어가고 있는 시스템들은 더욱 커진 사고 및 고장에 대한 위험을 내재하게 된다. 또한 대형 복합 시스템에서 발생하는 사고 및 고장은 바로 큰 재산피해나 인명피해와 직결 될 수 있다. 따라서 체계적인 안전관리의 필요성이 점차 커지고 있다. 이에 대응하여 철도, 항공, 해양 등의 산업에서는 각 산업에 적합한 안전관리체계를 수립하려 노력하고 있으며, 표준 및 매뉴얼을 제정하여 보급에 앞장서고 있다. 또한 시스템에서 전장품 및 소프트웨어가 차지하는 비중이 커지면서 기능안전이 안전분야의 이슈가 되고 있다. 이에 따라 IEC 61508, ISO 26262, IEC 61511 등 기능안전관련 표준들이 제정되어 기능안전을 달성하기 위한 기반을 제공하고 있다. 한편 국내 철도산업에서도 철도안전법의 재정을 기점을 철도 산업전반에 걸쳐 많은 환경변화가 이뤄지고 있고 이에 대응하기 위해 철도 안전시스템을 바탕으로 한 안전관리체계를 구축하였다. 한편 다양한 운영체계를 갖고 있는 철도시설 및 운영기관이 존재하는 국가 철도 안전관리체계의 안전규제를 체계화하기 위해서는 체계적인 요구사항의 분석에 따른 시스템 아키텍처의 설정이 요구되고 있다. 이러한 아키텍처의 설정은 현재에 대한 분석과 미래의 철도안전시스템의 특성을 구조화하여 향후 비전을 프레임워크로 표현함으로서 구현이 가능해진다. 본 논문에서는 현재의 안전관리체계의 도입 배경 및 도입 현황에 대해서 분석하고, 최근 기존의 안전관리체계와 더불어 최근에 안전분야에서 이슈가 되고 있는 기능안전 표준을 반영한 안전관리체계의 구축을 위해 안전관리체계에 대한 아키텍처를 구현하고자 하며 이때, 모델링을 바탕으로 한 접근을 제시한다.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.450-456
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• 2009

In accordance with the development of recent computer technology, the dependency of railway signaling system on the computer software is being increased further, and accordingly, the testing for the safety and reliability of railway signaling system software became more important This thesis suggested automated an analysis tool for S/W metrics on this railway signaling system, and presented its result of implementation. The analysis items in the implemented tool had referred to the international standards in relation to the software for railway system, such as IEC61508 and IEC 62279. This automated analysis tool for railway signaling system can be utilized at the assessment stage for railway signaling system software also, and it is anticipated that it can be utilized usefully at the software development stage also.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.263-272
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• 2009

Nowadays, lots of software that have similar functions is being produced. Hence it is getting more important to select the best and suitable software for each individual or company. Moreover, there are few trustworthy materials regarding to the objective procedure and criteria for the best evaluation of the software quality. To overcome these problems, benchmarking has been carried out. However, benchmarking is also confronting the limit of quality evaluation verification due to the difficult of the objectification of the major test items. To solve these problems, some others try to evaluate the quality of software using objective criteria of evaluation based on ISO/IEC standards. Nevertheless, this method using these defined evaluation items and criteria may result in not very reliable outcome. Therefore, this paper offers the evaluation items reflected in the characteristics of each software in order to prove the validity of the proposed method. Moreover, the objective and quantitative criterion which analyzes and reflects the organization characteristics using AHP methodology is applied to the experiment and performance evaluation. Hence we expect that the proposed method provides the needs of the re-establishment of software quality evaluation criteria and the improvement of process in terms of management.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.79-86
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• 2008

H.264/AVC is the newest international video coding standard developed by the joint ITU-T and ISO/IEC standards organizations. This newest video coding standard offers much higher coding efficiency than the H.261, H.263 and MPEG-4. But it has high computing complexity and high H/W resources wasting problem. This paper described the two unit parallel pipeline structure. This new structure comparing with standard model decreased the computing complexity of 67% and the H/W resources waste of 3%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.815-825
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• 2015

DNP3(Distributed Network Protocol) is one of the most representative protocols which is used in SCADA(Supervisory Control and Data Acquisition) system. IEC 62351 is listing the integrity, confidentiality, availability and non-repudiation or accountability as the security requirement. However, IEEE Std. 1815 that is DNP3 standards does not define a mechanism for non-repudiation or accountability. In this paper, we propose a non-repudiation of origin technique about the sender of critical ASDU and implement the proposed scheme using software such as OpenSSL and SCADA source code library.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1E
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• pp.38-44
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• 2010

This paper is based on our comments and proposed amendments to the documents, Annex A, Phantom for determining Maximum Depth of Penetration, and Annex B, Local Dynamic Range Using Acoustical Test Objects 87/400/CDV. IEC 61391-2 Ed. 1.0 200X, prepared by IEC technical Committee 87; Ultrasonics. The documents are concerned with the influence of microstructure of reference target material on the ultrasonic backscattering. Previous works on the attenuation due to backreflection and backscattering of reference target materials are reviewed. The drawback to the use of ungraded stainless steel and metallic materials without microstructural data such as, crystal structure, basic acoustic data of sound velocity and attenuation, grain size, roughness and elastic constants has been discussed. The analysis suggested that the insightful conclusion can be made by differentiating the influence arising from target size and microstructure on the backscattering measurements. The microstructural parameters are associated with physical, geometrical, acoustical and mechanical origins of variation with frequency. Further clarification of such a diverse source mechanisms for ultrasonic backscattering would make the target material and its application for medical diagnosis and therapy simpler and more reliable.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.533-538
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• 2005

In this paper we identity the hazard using HAZOP study for ATSRX which is a subsystem of the ATP system, and we study a safety management method for the mitigation of the risk to the acceptable level. ATSRX is a device that make a train which has a ATP system operate in ATS line. For this ATSRX send a induction signal with ATS system to vehicle controller. Thus ATSRX can be said a safety equipment that makes a train operate safely. In order to identify the hazard for the internal faults in ATSRX system, we employ HAZOP study method which is recommended as hazard identification in IEC 62278, RAMS requirements in railway signal, and also it provide the detail activity in IEC 61882. Thus, in this paper we perform HAZOP study based on ATSRX related standards and using the assessment of the identified hazard we study a method to guarantee the system safety through the change of the design to mitigate the risk to the acceptable level.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.251-261
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• 2006

FMEA(Failure Mode and Effects) is a procedure for the analysis of a system to identify the potential failure modes, and their effects and causes to reduce or mitigate the critical effects of the system. Recently, FMEA is used in various industries and it is specialized in each industry. For instance, MIL-1629a in Military industry, SAE-J1739 in Automotive industry and other industry are using specialized FMEA method. Though Railroad industry requires the high reliability system, it does not have the FMEA method which is specialized to them. So in this paper, we examined the MIL-1629a, SAE-J1739, IEC-60812 and compared those standards. Furthermore, we propose the FMEA method that is specialized to the railroad system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.76-83
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• 2008

The neutral current is made of both the load unbalanced current and the 3rd harmonic. The 3rd harmonic which is the source of the main neutral current is generated from the loads using bridge rectifier circuits on their input produce currents. TV, computer and monitor which are belong to IEC 61000-3-2 Class D are the main 3rd harmonic current sources. In order to show the affect of the distribution system by these disturbances, this paper has studied the current standards of the Korea Electric and considers the problem of the neutral common.