• 한국군사과학기술학회지
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• 제17권4호
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• pp.404-412
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• 2014

We proposed a design method for squib current supply & interlock circuits in guided-missile fire control systems. In order to design squib current supply circuits, various missile squib loads including line resistance and squib devices have to be considered in advance minimizing probability of redesign of circuits and reducing the development cost by implementing the most proper squib current supply circuit. Also, we presented a hardware interlock logic instead of the commonly used software safety logic to improve the safety of guided-missile fire control systems. The proposed squib interlock circuit enhances safety requirements of guided-missile fire control systems. We confirmed that simulation and measurement results of the proposed design method are the same as theoretical analysis results.

• 산업경영시스템학회지
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• 제41권1호
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• pp.94-101
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• 2018

With the development of industrial technology and science, production and manufacturing facilities have been enhanced and improved, and the importance of the safety of workers has also been regulated and limited by various safety management methods. As a way to secure the safety of the workers from the production facility, the fail-safe and fool-proof methods are now being applied. Any possible insecure behavior and unsafe conditions can be removed by adopting the standards and specifications that are now secure the safety of workers and equipment. This research analyzes EN ISO 13849-1 international and European standards during CE certification. In order to secure acceptable reduced risks, the risk assessment process of ISO 12100 and the processes for reducing its risk are applied. In the current ISO 13849-1 standard, the criteria for the required performance level PLr (Required Performance Level) for the applicable risk and safety functions through the risk assessment are subjective and not subdivided. Therefore, the evaluation criteria are likely to cause judge's judgement error due to qualitative judgement. This research focuses on evaluation and acceptable performance level setting for the safety circuit of the equipment. We propose an objective and specific evaluation criteria to secure safety, and the proposed evaluation criteria are applied to the case study of the safety circuit for the equipment. In order to secure the safety of the entire safety circuit, the improvement of the MTTFd and DC level related to the SRP/CS (Safety-Related Parts of Control Systems)' lifetime is required for the future research.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.171-174
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• 2005

The circuit simulation analysis and diagnosis methods are used to instruments in detail when they give apparently abnormal readings. In this paper, a new simulator through an analysis of the important circuits modeling under severe accident conditions has been designed, the realization for a body work instead of the two sorts of the Labview & Pspice as an one order command in the Labview program. The program can be shown the output graph form the circuit modeling as an order commend. The procedure for the simulator design was divided into two design steps, of which the first step was the diagnosis methods, the second step was the circuit simulator for the signal processing tool. It has three main functions which are a signal processing tool, an accident management tool, and an additional guide from the initial screen.

• 한국안전학회지
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• 제13권2호
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• pp.22-29
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• 1998

The natural convection cooling of simulated electronic chips located on a printed circuit board(PCB) has been studied by Computer Aided Engineering(CAE). In CAE, 3-dimensional finite element model of simulated electronic chip was made to accomplish heat transfer analysis at each design stage of a printed circuit boards for thermal optimization. The simulated electronic chips are installed protrudent from the plate about 3mm. The materials the plates are epoxy and aluminum. The results show that the chip with relatively high heat generation rates should not be close to each other. It is found, as well that cooling effect for the aluminum plate is superior to the epoxy plate and location of maximum temperature is significantly influenced by the structure variation of PCB. In developing PCB and electronic chips, it's recommended that CAE is very useful to estimate to the distribution of temperature.

• 한국안전학회지
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• 제37권1호
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• pp.12-19
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• 2022

Circuit breakers are a crucial factor in ensuring the safety of a Direct Current (DC) grid. One type of DC circuit breaker, the Z-source DC circuit breaker (ZCB), uses a thyristor, which is a type of semiconductor switch. In the event of a fault in the circuit, the ZCB isolates the fault by generating a zero crossing current in the thyristor. The thyristor quickly and actively isolates the fault while generating a zero crossing current, but thyristor switch cannot control turn-off and the allowable current is lower than the current of the mechanical switch. Therefore, it is best to use a mechanical switch with a high allowable current capacity that is capable of on/off control. Due to the slow reaction time of mechanical switches, they may not isolate the fault during the zero crossing current time interval created by the existing circuit. In this case, the zero crossing current time can be increased by using the property that hinders the rapid change in the current of the inductor. This paper will explore whether adding system inductance to increase the zero crossing current time interval is a solution to this problem. The simulation of changing inductor and capacitor (LC) of the circuit is repeated to find an optimal change in the zero crossing current time according to the LC change and provides an inductor and capacitor range optimized for a specific load. The inductor and capacitor range are expected to provide optimization information in the form LC values for future applications of ZCB's using a mechanical switch.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.331-337
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• 2016

Purpose: The purpose of this study is the analysis of the failure mechanisms effect of circuit design characteristics of the ballast for LED Lamp Methods: Recently, electronic circuit of ballasts for LED lamp are being occurred on various failure mechanisms (whiskers, ion migration, heat dissipation problem, switching element damage) because electronic ballast circuit design characteristics are becoming more and more diverse. Results: we analysis failure mechanisms that occurs in accordance with the circuit design characteristics The ballast for LED lamp were divided into three different types (Type A, Type B, Type C) considering circuit design characteristics (thermal design, PCB patten spacing, element material) and it was experimented in the acceleration test conditions ($85^{\circ}C$, 85% R.H). Conclusion: We confirmed that failure mechanism of the ballast for LED Lamp had occurred differently in accordance with the circuit design characteristics.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.188-194
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• 2000

This study is about fault detection and fault area detection of LV circuit in Cab Cubicle system which have control of train to keep safety in High Speed Train. LV circuit is operated with diagnosis system like safety system. In this paper, we suggest a design and an implementation method to detect fault or to detect fault area automatically about LV circuit. The implemented system is tested successfully after implementation of some function. We expect reduction to diagnosis area or repair time by fault area module

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.602-609
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• 2000

This study is concerned with analysis and reliability evaluation of LV circuit in Cab Cubicle system which controls train to keep safety in High Speed Train. LV circuit is operated with diagnosis system as safety system. In this paper, we suggest a design and an implementation method to analyze LV circuit or trace fault area in LV circuit. This simulator uses 28 package modules and examines input and output by equations. So, user can trace where is fault area. The implemented system can be expected to be useful for long term test and evaluation of circuit in high speed train systems. We expect reduction to diagnosis area or repair time by this simulator.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.195-201
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• 2000

In this paper propose the new method on desig ESJ(Electrical Separation Joint) of Jointless Track Circuit. ESJ has a capability to saparate track signal electrically but enable connected a track section physically. So It is more proper to high-speed line. Because that demand a critical traveling safety and convient taking a train. In spite of existing ESJ of Jointless Track Circuit, UM7l, S-bond, According to new pole-zero placement and desgining tuining-unit It is possible to prove a independence of track-section and track-signal in new ESJ design of this paper

• 한국재난정보학회 논문집
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• 제19권4호
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• pp.844-850
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• 2023

연구목적: 본 논문은 백열전구를 이용하여 단락보호 전원공급 장치를 개발하고, 이를 학습 교구로 활용하는 연구에 관한 것이다. 전기 안전과 에너지 절약을 동시에 고려한 이 연구는 교육과 산업 분야에서 중요한 응용 가능성을 가지고 있다. 백열전구를 활용한 단락보호 전원공급 장치는 기존의 전원공급 장치와 비교하여 안전성과 효율성을 향상시키는데 도움이 되며, 학습 교구로 학습자들에게 전기 안전 교육을 제공함으로써 실생활에서의 전기 안전 지식을 습득하는데 기여한다. 연구방법: 백열전구를 사용하여 단락보호 전원공급 장치를 개발하고 개발된 장치의 성능 평가 및 안전성 확인을 통해 학습 교구로 활용할 수 있는 새로운 전원공급장치를 제작 한다. 결론:백열전구를 활용한 단락보호 전원공급 장치의 개발과 학습 교구로의 응용 가능성을 탐구한 연구이다. 이를 통해 전기 안전과 에너지 절약에 기여할 수 있는 혁신적인 솔루션을 제시하였으며, 교육 분야와 산업 분야에서의 응용 가능성을 열어놓았다. 이러한 연구는 전기 안전 및 에너지 관리 분야에서의 연구와 교육에 기여할 것으로 기대된다.