• International Journal of Safety
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• 제6권2호
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• pp.27-32
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• 2007

For last several decades with the achievement of fast economic development, the electrical fires occupies over 30 percent of total fire incidents almost every year in Korea and not decreased in spite of much times and efforts. Electrical fire cause diagnostics are to confirm a cause for the fire by examination of fire scene. Cause diagnosis methods haven't been systematized yet, because of limits for available information, investigator's biased knowledge, etc. Therefore, in order to assist the investigators and to find out the exact causes of electrical fires, required is research for an electrical fire cause diagnosis system using DB, computer programming and some mathematical tools. The electrical fire cause diagnosis system has two functions of DB and electrical fire cause diagnosis. The cause diagnosis is conducted by a case-based reasoning on a case base and rule-based reasoning on a rule base. For the diagnosis with high reliability, a mixed reasoning approach of a case-based reasoning and fuzzy rule-based reasoning has been adopted. The electrical fire cause diagnosis system proposes the electrical fire causes inferred from the diagnosis processes, and possibility of the causes as well.

• 한국안전학회지
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• 제29권2호
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• pp.12-17
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• 2014

This paper is aimed to analyze the characteristics of simultaneous voltage, current and temperature signals for poor connection on electrical connector. In order to attain this purpose, detected were the current and voltage signals on electric wire with series arc, named arc signals, and also monitored were the changes of RMS, instantaneous value of waveform in time domain and temperature value with video. Two states are made normal state over $5kgf{\cdot}cm$ and poor connections state below $0.5kgf{\cdot}cm$ by screw gage. In the voltage signal case, the voltage drop was increased with which the current was increased. In the current signal case, poor connections at the time interval 1~4A all showed "shoulder", as distinct difference from the normal state shown waveform pattern. In the temperature signal case, poor connections are twice at 1A and five times at 4A in the normal state. The temperature continues insulation of electrical wiring and connector can be carbonized. The results of this study will be effectively used in developing the preventive devices and system for electric fire by poor connections.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 사면안정 학술발표회
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• pp.213-220
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• 2000

Numerical modeling of cut slope has some limits in simulating the real slopes. In the case of 2D analysis of slope stability, it is assumed that slope is simply straight even when it is concave or convex in plan view. In this study, 3D analysis in curved shape slopes has been conducted for the comparison with 2D analysis in terms of failure mode and factor of safety. For this, 3D analysis by FLAC3D was compared with 2D analysis in plane strain condition and axi-symmetric model condition by FLAC. It was also observed how safety factors of slopes were affected by the variation of the tensile strength and cohesion, which are important variables to decide whether the slope fails or not. 2D analysis of concave slopes under plane strain condition showed much smaller safety factors by 16-40 % errors depending on the radius of curvature of slopes, compared to the more realistic values from 3D analysis. In case of convex slopes, the lower values by 7-10 % has been reported. 2D analysis of axi-symmetric model showed also smaller safety factors by 6-10 % and by 2-4 %, in case of concave and convex slopes, respectively. Such results are expected to contribute to the better understanding of failure process and could be applied for improved design of slopes.

• 정보과학회 논문지
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• 제43권6호
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• pp.662-667
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• 2016

차량 내 전기전자제어시스템이 급격히 증가하면서 이로 인한 안전사고가 이슈로 부각되고 있다. 그러므로 차량의 안전성을 확보하기 위해서는 개발 초기에 PHA, HAZOP 등을 활용하여 위험원을 식별하고, 이를 예방하기 위한 안전 메커니즘이 구현되어야 한다. 특히, HAZOP은 가이드워드 기반의 체계적인 방식으로 널리 활용되고 있다. 하지만, 시스템이 제공하는 최상위 기능으로부터 오동작을 찾아내기 때문에, 동작 과정상의 위험원을 충분히 식별하지 못한다. 또한 충분히 식별되지 않은 위험원으로부터 안전 요구사항을 정의하기 때문에 테스트케이스 설계에도 제한이 있다. 이에 본 연구에서는 시스템의 동작과정 정의에 유용한 사용사례 기술서와 HAZOP을 적용한 위험원 식별 그리고 안전 요구사항 기반의 테스트케이스 설계 방안을 제안한다. 본 연구의 효용성을 검증하기 위해 차량의 스마트키 제어시스템 사례를 제시하고, 기존 HAZOP 기반의 위험원 분석 결과와 비교한다. 본 연구를 적용하는 조직은 시스템 개발 초기에 위험원 및 안전 요구사항을 충분히 식별하고, 테스트케이스를 설계함으로써 개발 비용을 줄이고, 시스템 품질을 높일 수 있을 것으로 기대한다.

• 에너지공학
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• 제23권4호
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• pp.223-229
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• 2014

본 연구는 시뮬레이션 툴을 이용해 HCNG 연료의 폭발 특성에 대하여 고찰하였다. 충전소의 대량 가스누출로 인한 증기운 폭발과 저장용기 폭발에 의한 피해 범위를 예측하였다. HCNG 충전소에서 증기운 폭발이 발생할 경우 충전소 내부에 50~200kPa의 폭발압력이 형성되었다. 저장용기가 폭발할 경우 수소의 경우 과압이 미치는 거리는 59m, 복사열이 미치는 거리는 75m로 측정되었다. CNG의 경우 과압이 미치는 거리는 89m, 복사열이 미치는 거리는 144m로 예측되었다. 수소와 CNG를 혼합한 30%HCNG의 경우 과압이 미치는 거리는 81m, 복사열이 미치는 거리는 130m로 예측되었다. 폭발과압 및 복사열이 미치는 피해거리는 CNG가 가장 높게 나타났으며 HCNG는 CNG와 수소의 사이에 위치하였다.

• 한국안전학회지
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• 제34권1호
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• pp.90-97
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• 2019

This study is aiming to compare stair ascent transportation speed and physical burden of evacuation supporters according to the types of stair ascent transportation for vulnerable people experimentally. In this study, we measured heart rate of the supporters to indicate physical burden during the transportation. The subjects of this experiment were male students, age of 20-26. Experimental conditions were the ways of stair transportation and the weight of vulnerable people. The types of stair transportation were giving a piggyback ride and carrying a wheelchair. Each experimental trial was video-recorded for measurement of ascent speed and observing supporters movement. As a result of the experiment, as for the ascent transportation speed by piggyback ride from the first floor to the fourth floor, the average speed of the light case is 31 seconds and for the heavy case is 43 seconds. When it comes to the average speed of wheelchair transportation's average speed the light case is 1 minute and 11 seconds and the heavy case is 1 minute and 49 seconds. Therefore, it was indicated that when the weight of a vulnerable people is lighter, the transportation speed is faster. The heart rates of evacuation supporters are different depending on transportation methods or individual's condition but as repetitive transportation increases, they tend to reach the maximum heart rates.

• 한국자동차공학회논문집
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• 제16권6호
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• pp.1-9
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• 2008

The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situation including the worst case such as rollover, spin-out and so on. Although the known NHTSA J-turn and Fish-hook steering maneuvers are applied for the vehicle performance assessment, they aren't enough to estimate other possible worst case scenarios. Therefore, it is crucial for us to verify the various worst cases including the existing severe steering maneuvers. This paper includes the procedure to search for other useful worst case based upon the existing worst case scenarios mentioned above and its application in simulation basis. The only human steering angle is selected as a design parameter here and optimized to maximize the index function to be expressed in terms of either roll angle or yaw rate. The obtained scenarios were enough to generate the worst case to meet NHTSA worst case definition (ex.2-inch wheel lift). Additionally, as an application, the worst case steering maneuver is acquired for the vehicle to operate with a simple ESP system. It has been concluded that the new procedure in this paper is adequate to create other feasible worst case scenarios for a vehicle system both with an intelligent safety control system and without it.

• Journal of Ship and Ocean Technology
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• 제4권4호
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• pp.1-18
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• 2000

The paper describes a formalisation of a Design for Safety methodology in an integrated envi-ronment, outlines early developments of a software tool, and presents the results of an appli-cation of the methodology to a case study. The approach adopted attempts link safety per-formance prediction through the utilisation of appropriate technical tools, safety assessment deriving from risk-based methodologies and disparate design activities and issues. Black-board systems have been utilised as the platform in the development of the integrated design environment, allowing safety assessment to become an integral part of the design process. Finally, the case study addresses the application of the developed methodology to three dif-ferent arrangements of a conventional passenger Ro-Ro vessel, with the aim to demonstrate the validity of the process and methodology adopted. The findings are presented and dis-cussed, and recommendations given for the way forward.

• 대한안전경영과학회지
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• 제10권3호
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• pp.55-62
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• 2008

This is to prevent accidents that can be caused during the process of hospital logistics and accidents in relation to the traceability of medical wastes. And this is also to set up the logistic management system of medical wastes is hospital where the safety of patients shall to regard as the first priority. through these case studies effective operating plans shall be provided.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2007년도 추계학술대회
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• pp.85-95
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• 2007

It compared subcontractor with contractor that are wages, the labor hour and labor condition of the work environment back are inferior relative. The subcontractor which basically the contract workers evade the dangerous process or the difficult work, the dirty work back what is called 3D the case which does to keep a business is many. so With life it will be threatened consequent health directly. The possibility where the subcontractor will be exposed to danger work came to be high. Together the reason of subcontract at managing the big business the case which becomes accomplished in objective, about lower the immediacy safety&health problem, subcontractor assigned workers is the actual condition only it could not be deteriorated more in public finance of the supply and enterprise and technical ability insufficiency. Consequently it prevents the subcontract which danger work is insensitive from this research and immediacy of the subcontract workers who is weak hygiene circumstance complement the plan it will be able to secure the immediacy safety&health subcontract workers, substantially to prepare in the hazard subcontract proprietor.