• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.299-306
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• 1999

The ${\mu}$-processor based-controlled system is widely used in railway signaling system. The railway signaling systems are highly required safety and reliability. It is necessary to have a fault-tolerant and fail safe concept in ${\mu}$-processor based railway signaling system. In this paper, several architectures and circuits of fault-tolerant computer system is reviewed. The basic concept of the fault-tolerant computer system will be adapted total self checking, strong fail safe, fault display circuit, logic testing circuit and system switching concepts.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.157-165
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• 2001

In the brake systems, it is important to reduce the rear brake pressure in order to secure the safety of the vehicle in braking. So, there was some research that reduced and controlled the rear brake pressure exactly like a LSPV and a ELSPV. However, the previous research has some weaknesses: the LSPV is a mechanical system and its brake efficiency is lower than the efficiency of ELSPV, But, the cost of ELSPV is very higher so its application to the vehicle is very difficult. Additionally, when a fail appears in the circuit which controls the valves, the fail results in some wrong operation of the valves. But, the previous researchers didn't take the effect of fail into account. Hence, the efficiency of them is low and the safety of the vehicle is not confirmed. So, in this paper we develop a new economical pressure modulator that exactly controls brake pressure and confirms the safety of the vehicle in any case using a direct adaptive fuzzy controller.

• 한국안전학회지
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• 제39권1호
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• pp.33-40
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• 2024

This study analyzes the impact of regular preventive maintenance (PM) on reducing the failure rate and occurrence of falling accidents of industrial overhead doors. A reliable safety device model with an additional safety device, which is installed to replace a defective one, is proposed. The research methodology involves collecting breakdown and falling accident records, comparing and analyzing data before and after regular PM implementation, and experimenting with two types of retrofittable safety devices. Key findings are as follows. 1. Regular PM implementation significantly reduces the failure rate of old overhead doors. 2. A parallel structured model with two alternative safety devices can minimize falling accident risks. The study's contributions include the following. 1. The positive impact of PM on extending overhead door lifespan is quantified. 2. A general safety device model that can be retrofitted and used as replacement with a fail-safe function is proposed.

• 한국통신학회논문지
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• 제17권11호
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• pp.1279-1289
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• 1992

고장 방지 시스템은 하드웨어나 소프트웨어의 여분 (Redundancy)을 이용하여 신뢰도(Reliability) 및 안전도(Safety)를 향상 시킨다. 시스템의 대상 영역(application areas)에 따라 고장 마스크(fault mask), 고장검출(fault detection), 고장 확인(fault identification)등의 기법을 선택하여 이용한다. 본 연구에서는 최소의 하드웨어와 소프트웨어의 여분을 이용하는 DMR(Double Modular Redundancy) 시스템을 대기 모듈(standby module)과 Fail-safe 모듈로 동작 시킬때 신뢰도와 안전도의 특성을 비교 제시한다. 또한 자기 진단 프로그램의 과도 오류 방지 능력에 대한 시스템의 MTTF를 비교함으로서 과도 오류를 취급하는 효과적인 방법을 제시하였다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2000년도 추계 학술발표회 논문집
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• pp.79-82
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• 2000

필터 집진기는 집진효율, 내열, 그리고 내화학성이 우수하기 때문에 고온 정밀집진 또는 부식성 가스의 집진을 위하여 매우 유용한 장치이다. 그러나 세라믹이나 금속 필터를 사용하는 필터 집진기는 운전 시에 필터의 파손에 대한 잠정적인 우려가 있기 때문에 이를 극복하고 시스템의 신빙성을 100% 확보하는 것이 궁극적인 과제로 인식되고 있다. 고온 세라믹 필터의 활용이 가장주목시 되고있는 IGCC 집진의 경우 석탄가스화 및 탈황 과정에서 발생되는 분진을 고온고압에서 제거하여 가스터빈을 보호하는 공정으로써 운전중에 필터가 파손되면 그 부분으로 분진가스가 급격히 빠져나가 큰 분진 입자가 가스터빈으로 유입되고 심한 경우에는 파손된 필터의 파편이 여기에 동반될 수 있다.(중략)

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2001년도 춘계학술대회
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• pp.67-75
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• 2001

Circuitry to be connected to a Telecommunication Network consists of SELV CIRCUITS or TNV CIRCUITS. So International Standards, like as ITU-T Recommendation K.11, UL 1950, CSA C22.2 950 have been taken to reduce the risk that the Overvoltages from the power lines and from electrictraction lines, that may be received from the telecommunication network. Legal requirements may exist regarding permission to connect equipment having PTC components to a telecommunication network. Surge suppressors that bridge the insulation shall have a minimum d.c. sparkover voltage of 1.6 times the rated voltage or 1.6 times the upper voltage of the tared voltage range of the equipment. If left in place during electric strength testing of insulation, they shall not be damaged. In this work, The Conception ＆ Fail-Mode Analysis of PTC components for Over-Current Protection is proposed. It guarantees the protection for PL Claim about this Subject.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권1호
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• pp.1-9
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• 2000

In this paper, a design method of fault-tolerance is presented for the nuclear digital control systems composed of software and hardware. As a quantitative design method measure of fault-tolerance, we used Reliability, Availability and Safety. To implement the proposed fault-tolerance, a prototype system has been devised for the digital control systems and a quantitative method of 'Markovian Model' is applied. The results provide the appropriate degree of redundancy and diversity, and fail-safe.

• 한국안전학회지
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• 제6권1호
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• pp.5-13
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• 1991

Fail-safe design of machine elements or structural members is very aim of the whole mankind. Fracture occurs generally from cracks that exist originally or produced from flaws. The most important job we have to do is to make stopping or decreasing the crack growth rate. For fail-safe design variable thickness plates have been used as structural members in practical engineering services. In this paper, optimum design of CT type plate with varlng thickness is studied with the theoritical analysis. The theoritical analysis was based on the stress concentration and nominal stress analysis. From the study, the optimum design curve was determined for use of designing of such structures using the computer analysis program of optimum design.

• 한국자동차공학회논문집
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• 제20권6호
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• pp.83-91
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• 2012

In recent days, the study on hybridization of the heavy-duty is going on, actively. Especially, the improvement of fuel economy can be maximized in the intra-city bus because it drives the fixed route. For developing the hybrid electric intra-city bus, optimized control strategy which is possible to be applied with real vehicle is necessary. If the real-time control strategy is developed based on the HILS, it is possible to verify the real-time ability and fail-safety function which has the vehicle stay in safe state when the functional errors are occurred. In this study, the HILS system of series hybrid electric intra-city bus is developed to verify the real time control strategy and the fail-safety functions. The main objective of the paper is to build the HILS system for verifying the control strategy (rule-based control) which is implemented to reflect the Dynamic Programming results and fail-safety functions.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.433-436
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• 2007

We analyzed the sloped ground safety factor, which is not presented in the design specification, using a computational analysis program L-Pile Plus 13.8. To achieve this we chose a required parameter set and a level ground safety factor presented in the design specification, and then determined its values comparing with the change of the safety factor according to the parameter. Using these parameters, we estimated the sloped ground safety factor for the slope of 35 degrees considering the improvement value of the slope presented in the design specification. As a result of this analysis, we obtained the smaller safety factor by about 0.7 times than the case of the level ground and verified that a number of concrete poles fail to assure 1 degree of the safety factor. We, therefore, concluded that an adjustment of the embedment depth is required in the case of the sloped ground.