• Title/Summary/Keyword: Safety-critical System

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Estimator Design for Road Friction Coefficient and Body Sideslip Angle for Use in Vehicle Dynamics Control Systems (차량 동역학 제어기를 위한 노면 마찰계수 및 차체 미끄럼각 추정기 설계)

  • 박기홍;허승진;백인호;이경수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.2
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    • pp.176-184
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    • 2001
  • The VDC(Vehicle Dynamics Control) is a control system whose target is to improve vehicle stability under critical motion. The system has a good potential of becoming a standard active safety unit in passenger vehicles since it can be implemented on top of the ABS/TCS system with little extra cost. This, however, is possible only when the signals that the VDC system demands can be obtained with sufficient accuracy. In this research, estimators for the road friction coefficient and body sideslip angle have been designed. The two variables have great influence upon performance of the VDC system but not directly measurable. For the estimator design, the Newton method and the nonlinear observer theory have been exploited. The performance of the estimator have been verified via simulations on critical driving conditions.

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Human Factors Design Review of CFMS for Improving the Safety of Nuclear Power Plant (원전의 안전성 제고를 위한 CFMS의 인간공학적 설계 검토)

  • 이용희;정광태
    • Journal of the Korean Society of Safety
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    • v.12 no.4
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    • pp.201-208
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    • 1997
  • In order to improve the safety of nuclear power plant, we performed a human factors review for the CFMS(Critical Function Monitoring system) design of nuclear power plant. Three works were performed in this study. In first work, we developed human factors engineering program plan(HFEPP) and human factors engineering verification and validation plan (HFE-V & V plan) to effectively perform CFMS design and review. In second work, we identified human engineering discrepancies(HEDs) for CFMS design through human factors design review and proposed those resolutions. In the third work, we developed the evaluation and management methodology for identified KEDs. Methodology developed in this study can be used in other complex system as well as in CFMS design review.

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Fault Detection Signal for Mechanical Seal of Centrifugal Pump (원심펌프용 메커니컬 씰 결함 검출 신호 특성)

  • Jeoung, Rae-Hyuck;Lee, Byung-Kon
    • Journal of the Korean Society of Safety
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    • v.27 no.3
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    • pp.20-27
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    • 2012
  • Mechanical seals are one of main components of high speed centrifugal pumps. So, it is very important to detect the faults (scratch, notch, indentation, wear) of mechanical seals since the damage of seal can cause a critical failures or accidents of machinery system. In the past, many researchers mainly performed to detect the seal fault using the time signals measured from sensors. Recently, studies are focused on the development of on-line real time monitoring system. But study on the feature parameters used for fault detection of mechanical seals has a little been performed. In this paper, we showed feature parameters extracted from accelerated and acoustic signals by using the discrete wavelet transform (DWT), alpha coefficient, statistical parameters. And also verified the possibility for fault detection of mechanical seal.

A Study of Plans for systemizing Railway System Safety Technology Tree (철도시스템안전 기술트리 체계화 방안에 관한 연구)

  • Hong Seon-Ho;Cho Yeon-Ok
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.623-629
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    • 2005
  • A technical road map is one of critical research methods which include mid/long term strategies and objectives. There are many of projects conducted using this road map. A technical tree is used at the step of planning of the projects. This research was aimed at reviewing previous systems for conducting researches for and a basis required for improving railway safety in the future by finding out inconsistency arising from physical WBS, which is methodology of defining in existing railway technical trees. In the process of this research, we considered differences between systems safety and prevention as well as natures of them using the established technical tree, and set up plans for improving technical tree to secure railway safety as an integrated system.

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Investigation of the various properties of several candidate additives as buffer materials

  • Gi-Jun Lee;Seok Yoon;Taehyun Kim;Seeun Chang
    • Nuclear Engineering and Technology
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    • v.55 no.3
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    • pp.1191-1198
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    • 2023
  • Bentonite buffer material is a critical component in an engineered barrier system (EBS) for disposing high-level radioactive waste (HLW). The bentonite buffer material protects the disposal canister from groundwater penetration and releases decay heat to the surrounding rock mass; thus, it should possess high thermal conductivity, low hydraulic conductivity, and moderate swelling pressure to safely dispose the HLWs. Bentonite clay is a suitable buffer material because it satisfies the safety criteria. Several additives have been suggested as mixtures with bentonite to increase the thermal-hydraulic-mechanical-chemical (THMC) properties of bentonite buffer materials. Therefore, this study investigated the geotechnical, mineralogical, and THMC properties of several candidate additives such as sand, graphite, granite, and SiC powders. Datasets obtained in this study can be used to select adequate additives to improve the THMC properties of the buffer material.

A Study on Safety Evaluation Methods for Electric Multiple Units (도시철도차량의 안전진단평가 기법에 관한 연구)

  • Chung J.D.;Han S.Y;Park K.J.;Park O.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.374-377
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    • 2005
  • Automobile is in charge of most transportation system in modern urban city. However, in fact, cause of problem of road state, environment, and the other reasons, urban transit system is using as Mass Transit nowadays. Nevertheless Urban transit system is considering many kind of safety fact of that system which is increasing continuously nowadays, it occurs various train accident. This paper describes 3D Dimensional Measurement(EDM testing) and tensile testing results of carbody structure for crashed EMU(Electric Multiple Units). Tensile tests were performed on two different types of specimens in order to evaluate the strength changes before and after damages, obtained from plastic deformed area and nondeformed region of the crashed EMU. And Structural analysis of EMU was performed for the criteria of safety assessment. Structural analysis using commercial I-DEAS software provided important information on the stress distribution and load transfer mechanisms as well as the amount of damages during rolling stock crash. The testing results have been used to provide the critical information for the criteria of safety diagnosis.

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The development standard research for railway safety software (철도 안전 소프트웨어를 위한 개발 기준 연구)

  • Lee, Young-Jun;Kim, Jang-Yoel;Cha, Kyung-Ho;Cheon, Se-Woo;Lee, Jang-Soo;Kwon, Ki-Choon;Jung, Ui-Jin
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.968-973
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    • 2007
  • The systems such as the railway control system, satellite control system and nuclear power plant control system are the safety critical systems because the failure of them could lead to risk significant events. These softwares of digital systems must follow the life cycle process from the beginning of software development to guarantee their safety and reliability. The NRC(Nuclear Regulatory Commission) Reg Guide of nuclear fields, the RTCA/DO-178B standard which is used to acquire the certification for software in industrial aero field in European Union and United State, the DEF STAN 00-55 standard for the safety of electronic weapon in England, the IEC 601-1-4 for medical equipment and the IEC 62279 for railway system recommended the development life cycle. This paper introduces the development process and compares each other. Also it indicates applicable development criteria for the software of systems related to railway fields and describes the detailed procedure of development criteria. We describe the procedure to make the software development criteria in nuclear filed. For the software development related to railways, the process from plan phase to maintenance phase must be satisfied. The safety and reliability is guaranteed through these standards.

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A SCM System Selection Problem using AHP Technique based on Benefit/Cost Analysis (편익/비용분석 기반의 AHP 기법을 이용한 SCM 시스템 선정 모델)

  • Seo, Kwang-Kyu
    • Journal of the Korea Safety Management & Science
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    • v.11 no.2
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    • pp.153-158
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    • 2009
  • An optimal selection problem of SCM system is one of the critical issues for the company's competitiveness and performance under global economy. This paper presents a hierarchy model consisted of characteristic factors for introducing SCM system and an AHP (Analytic Hierarchy Process) based decision-making model for SCM system evaluation and selection. The proposed model can systematically construct the objectives of SCM system selection to meet the business goals. This paper focuses on selecting an optimal SCM system considering both all decision factors and sub-decision factors of a hierarchy model. Especially, the benefit/cost analysis is applied to choose SCM system. A case study shows the feasibility of the proposed model and the model can help a company to make better decision-making in the SCM system selection problem.

A Study on the Temporary Storage Facility for Mitigating the Leakage Accident (누출 사고 완화를 위한 임시 저장 시설에 관한 연구)

  • Song, Hyeon Oh;Lee, Chang Jun
    • Journal of the Korean Society of Safety
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    • v.35 no.3
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    • pp.1-5
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    • 2020
  • The leakage accident from a storage tank in an oil refinery plant occurred in April 2014 and the total loss is KRW 18 billion. This accident has prompted many companies to develop their own mitigation system to minimize the loss of the leakage accident. The aim of this study is to design the temporary storage facility system for dealing with leakage accidents. The basic concept of this system is that the leakage fluid of a hazardous material flows into a temporary storage tank and this is transferred to a spare tank by a pump as avoiding the overflow of a temporary storage tank. In order to design this system, the leakage velocity and quantity according to time series should be evaluated. In addition, a proper pump capacity should be determined to avoid repeating the pump switching on and off frequently. In this study, the benzene tank is selected to verify the efficacy of this system. This study can play a critical role to provide a guideline for designing a new system.

Practical Application of HACCP Concepts in Korea -Using the Canadian Food Safety Enhancement Program- (국내에서의 HACCP 개념의 실용화에 관한 연구 -캐나다 FSEP를 중심으로-)

  • ;Scott A. McEwen
    • Journal of Food Hygiene and Safety
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    • v.14 no.1
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    • pp.104-114
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    • 1999
  • This study was conducted to find out the proper ways of implementation of Hazard Analysis Critical Control Point (HACCP) concepts applicable to the current Korean food inspection system. The following recommendations are based on an in-depth review of the Canadian Food Safety Enhancement Program (FSEP), which is one of the leading HACCP programs adapted to the food industry. Since 1997, the HACCP system has been voluntarily applied to meat processing plants in Korea in accordance with the Food Protection Law. But the guidelines are obscure and inadequate to expand to the diversity of food plants, and are therefore only applied to a limited number of plants of small scale enterprise. For these reasons, it is necessary to prepare an enhanced food safety control program focused not only on the HACCP plants but also on the non-HACCP plants. The national program should be the fundamental framework of a food safety control policy enforced by all the relevant authorities. The Prerequiste Program of Canadian Food Inspection Agency and Sanitation Standard Operating Procedures (SSOP) of FSIS are good example programs for the non-HACCP plants. These programs, which are a major part of the HACCP system, could easily be adapted to the Korean food industry. To improve the current HACCP implementation guideline, it is necessary to develop a detailed implementation manual, generic HACCP model, training program, and an audit program.

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