• 한국안전학회지
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• 제29권3호
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• pp.56-63
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• 2014

This study proposes a new control approach for efficient vibration suppression of two identical adjacent structures. The conventional control approach of two adjacent structures is to interconnect the two structures with passive, semi-active or active control devices. However, when the two adjacent structures are identical to each other, their dynamical behaviors such as frequency and damping properties are also the same. In this case, the interconnected control devices cannot exhibit the dissipative control forces on the both structures as expected since the relative displacements and velocities of the devices become close to zero. In other words, the interconnection method does not work for the twin structures as enough as expected. In order to solve this problem, we propose several new control approaches to effectively and efficiently reduce the identically-fluctuating responses of the adjacent structures with minimum control efforts. In order to demonstrate the proposed control systems, the proposed several control systems are optimally designed and their control performances are compared with that of the conventional optimal control system where each TMD(tuned mass damper) is installed in each structure for independent control purpose. The simulated results show that one of the proposed control systems(System 04) is able to guarantee enhanced control performance compared with the conventional system.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.573-584
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• 2016

최근 철도 열차제어시스템은 최첨단 기술로 인한 무선통신기반 개발의 수요와 이에 따른 환경의 다변화, 설계 정보의 복잡성, 시스템 설계에 대한 추적성 등 여러 요인으로 인해 모델기반 설계와 안전에 대한 쟁점도 증가하고 있다. 이에 따라 기존의 열차제어시스템에서 다루는 지상 설비 설계에 대한 모델기반 설계와 단계별 안전 활동 강화의 필요성 역시 강조되고 있다. 이를 해결하기 위해서 본 논문에서는 먼저 열차제어시스템에 대한 효과적인 개발을 위하여 모델기반 설계를 수행하였고 이는 SysML(System Modeling Language)을 활용하여 표현하였다. 열차제어시스템의 안전성 향상을 위하여 설계 모델을 활용할 수 있는 시험 시나리오를 생성하였다. 생성한 시험 시나리오에 모델기반 설계를 수행한 차상중심 열차제어시스템을 적용하여 사례 연구를 수행하였고 이에 대한 결과를 분석하여 본 연구의 활용 가능성을 입증하였다. 본 연구의 결과를 토대로 안전성 향상 접근에 대한 시험 활동 재정립을 통해 개선함으로써 향후 모델을 기반 설계로 수행된 열차제어시스템 개발시 개념설계에서 발생할 수 있는 비용 및 시간을 절감 시킬 수 있을 것으로 기대된다.

• 한국식품영양학회지
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• 제27권3호
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• pp.447-457
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• 2014

A research was conducted on Seoul regional elementary, middle, and high school nutritionists to study about their perception of HACCP control standards & performance conditions and sanitation & safety inspection, to seek for more efficient methods of school meals' sanitation system settlement. All surveys were distributed and collected via email. A total of 305 survey papers were collected, and out of these, 300 school results were analyzed. As for CCP 1 performance conditions, 43.3% of the nutritionist put emphasis on temperature control for cooking duration and 71.0% said that they manage both temperature and PHF food control. In CCP 2 stage, 65.8% of the nutritionists maintained the food's temperature, and 56.7% documented the recordings after cooking. A total of 79.3% of the schools scored above 90 points on school meal sanitation & safety inspection, 3.72 points on necessity for revisions, 3.38 points on objectivity, and 3.34 points on reliability. As for these results, a clear CCP control criteria as well as training must be set. Also, because the necessity of revision for sanitation & safety inspection is higher than reliability and objectivity, appropriate complementary measures must be taken.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1195-1201
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• 2011

Since the release of safety standard IEC 61508 which defines functional safety of electronic safety-related systems, SIL(Safety Integrity Level) certification for railway systems has gained lots of attention lately. In this paper, we propose a new design technique of the computer board for train control systems with high reliability and safety. The board is designed with TMR(Triple Modular Redundancy) using a certified SIL3 Texas Instrument(TI)'s TMS570 MCU(Micro-Controller Unit) to guarantee safety and reliability. TMR for the control device is implemented on FPGA(Field Programmable Gate Array) which integrates a comparator, a CAN(Controller Area Network) communication module, built-in self-error checking, error discriminant function to improve the reliability of the board. Even if a malfunction of a processing module occurs, the safety control function based on the proposed technique lets the system operate properly by detecting and masking the malfunction. An RTOS (Real Time Operation System) called FreeRTOS is ported on the board so that reliable and stable operation and convenient software development can be provided.

• 한국안전학회지
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• 제19권1호
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• pp.44-48
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• 2004

The smoke and toxic gases generated from the building fires are proved to cause human death. Therefore, the necessity and significance of smoke control have been emphasized, and lots of studies for developing improved smoke management system have been carried out. In this study, the experiments were conducted to evaluated a function and performance in newly developed smoke management system using mechanical pressurization. As a result of this experiment, the differential pressure was 40Pa${\sim}$60Pa and the air velocity through the door was 0.7m/s between safety zone and fire zone. The functional pressure control equipment which could make proper pressure and maintain differential pressure between safety zone and fire zone was developed. And it will give a lot of helps to evacuation activity for peoples in building and fire fighting.

• 한국가스학회지
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• 제8권1호
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• pp.30-36
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• 2004

최근 들어 가장 경제적인 에너지원 중의 하나인 가스의 사용이 확대되고 있으나 안전관리 미숙으로 수많은 가스사고가 발생하고 있다. 가스사고의 중요한 원인은 현행 가스안전제어시스템이 수동제어 매카니즘에 크게 의존하는데 있다 본 논문에서는 현장의 가스농도감지에서부터 차단밸브 제어까지 일련의 핵심적인 기능을 컴퓨터에 의해 자동화하고, 통합적으로 관리하기 위한 프로토 타입을 설계하고 구현하였다. 이러한 자동화 시스템은 디지털 네트워크로 연결되기 때문에 원격 제어가 가능하다는 특징이 있다. 특히, 본 논문에서 제안한 자동화 안전 시스템은 가스누출에 대한 상황파악 및 이에 대한 대처가 실시간대에 이루어지기 때문에 사고의 위험성과 피해를 대폭적으로 경감할 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.594-601
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• 2000

Communication Based Train Control System supports the easy maintenance ＆ management and also have the capability to send more informations than the existing one but is less expensive. Tolerance against fault/failure and reliable data transmission are very important issues with this system since it has the responsibility of man's safety. In this paper, we suggested the schemes to support the reliable transmission quality and fault safety. Also we verified through simulation.

• 한국기계기술학회지
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• 제20권6호
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• pp.929-935
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• 2018

This paper develops a flow control block for a hydraulic system of a tunnel boring machine. The flow control block is a necessary component to ensure stability in the operation of the hydraulic system. In order to know the pressure distribution of the flow control block, the flow analysis was performed using the ANSYS-CFX. It was confirmed that the pressure and flow rate were normally supplied to the hydraulic system even if one of the four ports of the flow control block was not operated. In order to evaluate the structural stability of the flow control block, structural analysis was performed using the ANSYS WORKBENCH. As a result, the safety factor of the flow control block is 1.54 and the structural stability is secured.

• 한국안전학회지
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• 제25권6호
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• pp.75-80
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• 2010

본 논문에서는 일반용 전기설비 중에서 전기안전관리의 사각지대로 분류되는 보안등 전기설비를 대상으로 전기안전요소들을 계측하고 원격 모니터링 할 수 있는 보안등 원격점검시스템을 개발하였다. 단말기에서 센싱하는 누설전류는 위상차 측정법을 이용한 저항성분 누설전류(Igr) 측정 알고리즘을 이용하였으며, 계측데이터 전송을 위한 중계기와 MMI에서 모니터링 할 수 있는 시스템을 제작하였으며, Igr 누설전류 검출 알고리즘의 타당성을 확인하기 위해 실험실 기반의 성능시험으로 누설전류의 안정도를 확인하였다.

• 한국안전학회지
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• 제18권2호
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• pp.40-45
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• 2003

To evaluate the smoke control systems, the large eddy simulation turbulence model based Fire Dynamics Simulate was applied to a 2m $\times$ 2m $\times$ 2.4m room with an opening. The smoke removal rate was investigated for three different smoke control systems: ventilation, extraction and pressurization. When the opening was closed, the smoke removal rates of the smoke control systems were almost the same as expected. The pressurization system showed a lower smoke removal rate compared with the other two smoke control systems for the room with the opening, and hence the pressurization system might not be efficient for a place with large openings. It was shown that the lower extraction flowrate is, the longer time the ventilation system requires to remove smoke. From these results, the ventilation system is recommended for subway stations where several large openings exist.