• 한국가스학회지
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• 제14권5호
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• pp.13-18
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• 2010

본 연구는 9% 니켈강재식 LNG 저장탱크용 통합제어안전관리시스템을 개발하고자 한다. 새로운 통합제어안전관리 시스템은 기존의 측정 및 제어시스템에 비해 압력, 변위, 하중을 측정할 수 있는 장치를 추가하였다. 또한, 측정된 데이터는 새로운 제어장치와 안전관리 시스템에 의해 통합되고 분석하는 프로세스를 동시적으로 진행하는 것이다. 초대형 완전밀폐식 LNG 저장탱크의 안전성과 효율성을 증가시키기 위해 통합제어안전관리시스템은 압력계이지를 추가하고, 내부탱크의 외측벽과 스티프너, 톱거더의 용접지역, 코너 프로텍션 탱크의 외측벽에 새로운 변위센서/압력센서를 설치하였다. 변위센서와 하중센서는 내부탱크와 코너 프로텍션 탱크의 9% 니켈강재 구조물에 대한 파손징후를 제공할 수 있고, 내부탱크로부터 누설되는 LNG를 감시할 수 있다. 기존의 누설센서는 내부탱크와 코너 프로텍션 사이의 단열지역에 설치한 누설감지기에 의해 경고신호가 접수될 때까지도 9% 니켈강재 탱크의 파괴에 대한 적절한 정보를 제공하지 못한다는데 문제가 있다. 따라서, 새로운 통합제어안전관리시스템은 온도, 압력, 변위, 하중, LNG의 밀도 데이터를 수집하고 분석하기 위한 것으로, 탱크시스템의 안전성과 내부탱크의 누설을 제어하기 위한 시스템이다. 또한, 디지털 데이터는 9% 니켈강재로 제작한 탱크의 안전성에 관련된 변위와 하중, LNG의 액위와 밀도, 쿨다운 공정, 누설, 압력 등을 제어하기 위해 측정한다.

• 한국안전학회지
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• 제32권6호
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• pp.81-88
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• 2017

This study deals with the optimal design of a hybrid control system composed of a combination of active control system and passive control system for effective seismic performance improvement of two adjacent structures. The proposed hybrid control system adopts a configuration of installing an active control device in one building and connecting two adjacent structures with a passive control device so that the one-side active control force can be bi-directionally applied to both buildings through the passive connecting devices. In order to derive the optimal performance of the proposed system, the design parameters of the passive and active control systems were searched using the genetic algorithm. Numerical simulations of 10-story and 8-story buildings have been performed to verify the effectiveness of the proposed technique. For the purpose of comparison, the conventional independent control system with two identical active control systems being installed separately for each structure was also optimally designed and its seismic response has been evaluated as well. From the comparative results of the two control systems, it is demonstrated that the proposed hybrid control system requires larger control force for its one-side active control device than the conventional independent control system does for each of both-side active devices, but quite less than the total control force required for both-side devices of the independent control system, while maintaining similar seismic performance. Therefore, the proposed system is more economical and reliable than the conventional independent control system with two identical active devices.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.460-467
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• 2010

In this study, the parameters of the feedwater control system (FWCS) of the OPR1000 type nuclear power plant (NPP) are optimized by response surface methodology (RSM) in order to acquire better level control performance from the FWCS. The objective of the optimization is to minimize the steam generator (SG) water level deviation from the reference level during transients. The objective functions for this optimization are relationships between the SG level deviation and the parameters of the FWCS. However, in this case of FWCS parameter optimization, the objective functions are not available in the form of analytic equations and the responses (the SG level at plant transients) to inputs (FWCS parameters) can be evaluated by computer simulations only. Classical optimization methods cannot be used because the objective function value cannot be calculated directely. Therefore, the simulation optimization methodology is used and the RSM is adopted as the simulation optimization algorithm. Objective functions are evaluated with several typical transients in NPPs using a system simulation computer code that has been utilized for the system performance analysis of actual NPPs. The results show that the optimized parameters have better SG level control performance. The degree of the SG level deviation from the reference level during transients is minimized and consequently the control performance of the FWCS is remarkably improved.

• 품질경영학회지
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• 제46권3호
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• pp.411-424
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• 2018

Purpose: The purpose of this study is to improve submarine TACM launcher system safety device performance. Methods: In this study, EPLD(Electrically Programmable Logic Device) control and time sharing method to the safety device actuator motor and discrete signal processor in launch control panel were used to resolve unusual performance of safety system. Results: The result of this study are as follows; First, sporadic stopping of safety device actuator motor due to insufficient In-Rush current was resolved. Second, repeat of safety device condition as lock & release due to chattering for motor activating was resolved. Third, simultaneous release function for safety device actuator was available. Conclusion: The unusual performance of function for submarine TACM launcher system was overcame by applying EPLD control and time sharing method. The suggestions were proved by performance test in the pressure chamber. The results of this study enhanced survivability of ${\bigcirc}{\bigcirc}{\bigcirc}$ class submarine from enemy torpedo.

• 대한안전경영과학회지
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• 제12권3호
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• pp.1-11
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• 2010

Establishing a framework, to explain the path to safety accidents considering major safety management factors such as physical conditions including on-site activities and workplace, as well as human factors as to labor, supervisors, or managers, would be effective as the basis to control project's risks by preventing disasters. Therefore, this study aimed to clarify the mechanism in safety management and disaster occurrence. In order to accomplish the purpose, it identified and classified the factors related to accidents, reviewed the causal relationships among them, and suggested the influence diagram. The results of this research are expected to contribute to reinforcing the preventive management, and facilitating the development of integrated site control system based on safety risks.

• 한국안전학회지
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• 제37권3호
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• pp.45-51
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• 2022

This paper focuses on a recently proposed asymmetric base-isolation coupling control system (ABiCS) for the vibration control of adjacent twin buildings. The ABiCS consists of inter-story diagonal dampers, a connecting damper between the two buildings, and a seismic isolation device at the base floor of one building. To investigate the control characteristics of ABiCS, a parametric study was performed by numerically simulating the 20-story twin buildings. In the parametric study, the control capacities of the inter-story diagonal dampers, connecting damper, and seismic isolation device were considered as varying parameters. The parametric study results indicate that the connecting damper between the two buildings reduces the responses of both buildings only at optimal or near-optimal capacity. In addition, adjusting the stiffness of the base isolation is found to be the most effective method for improving seismic performance and achieving cost-effectiveness. Accordingly, we presented a scenario-based performance improvement approach in which reducing the stiffness of the base isolation device could be an effective technique to improve the seismic performance of both buildings. However, note that checking the maximum allowable displacement of the base isolation device is essential.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1008-1011
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• 1996

Most control systems of power plants are using classical PID controllers for their process control. In order to get the desired control performances, the correct tuning of PID controllers is very important. Sometimes, it is necessary to retune PID controllers after the change of system operating condition and system design change, etc. Commercial auto-tuning controllers such as relay feedback controller can be used for this purpose. However, using these controllers to the safety-critical systems of nuclear power plants may be cause of unsafe operation, because they are using test signals for tuning. A new system identification auto-tuning method without using test signal has been developed in this paper. This method uses process input/output signals for system identification of unknown control process. From the model information of control process which was obtained from system identification approach, the optimal PID parameters can be calculated. The method can be used in the safety-critical systems because it is not using test signals during system modeling process.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.2070-2074
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• 2008

It is necessary to develop the requirement management system that could trace hazards and manage safety requirements for risk control of railway accident as low as reasonably practicable. In this paper, the requirement management system for control of railway accident risk is introduced. The requirement management system is containing the railway system configuration and safety activity related with identified hazards. The system shall be used to derive safety requirements for risk controland support the traceability of hazards on railway's operation & management. In the future, the system will be applied in the areas such as risk assessment and management, performing safety assurance and revising national regulations etc. for continuous safety improvement in the railway.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.1007-1008
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• 2005

• 한국식품위생안전성학회지
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• 제32권3호
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• pp.179-186
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• 2017

수입식품 안전관리 확보와 효율성 제고를 위한 목적으로 국가식품안전관리체계 평가도구를 활용하여 수출국의 국가식품안전관리체계 현황을 평가하고 이를 자국의 수입식품안전관리에 활용하는 방안에 대한 논의가 미국을 중심으로 진행되고 있다. 본 연구는 미국의 평가도구와 도구를 활용한 평가사례를 비교조사하고, 관계 전문가의 의견을 검토하여 시사점을 도출하였다. 미국 FDA가 개발한 식품안전관리체계 평가도구는 외국의 식품안전 전문성을 이용하여 수입식품 안전성을 확보하기 위하여 마련되었으며, 평가도구는 10개 기준으로 구성되어 외국의 전반적인 식품안전관리 수준을 판단할 수 있도록 고안되어 있다. FDA는 평가도구를 활용하여 뉴질랜드와 캐나다를 대상으로 평가를 실시하였으며 두나라 모두 미국의 식품안전관리체계와 동등한 것으로 인정하였다. 전문가 인터뷰에서는 국가식품안전관리체계 평가를 통해 수입 전 위생평가와 수입식품의 국경검사 빈도관리에 활용함으로써 수입식품 안전관리에 있어 국가예산의 효율적인 배분과 대국민 신뢰도 향상에 기여할 것이며, 향후 국가식품안전관리체계 평가에 대한 활용도 제고를 위해서는 국제적인 조화와 전문가 예산의 확보도 중요하다는 의견을 제시하였다. 미국의 평가도구 조사 분석과 전문가 인터뷰를 토대로 도출한 시사점으로는 국가식품안전관리체계 평가 논의의 국제적 흐름에 능동적으로 대응할 필요가 있으며, 국가식품안전관리체계 평가도구를 활용하여 국내 식품안전관리체계를 검토하는 것이 가능할 것이다. 아울러 식품안전관리체계 평가결과는 수출입 안전관리에도 활용할 수 있을 것으로 보이며, 이러한 국제흐름에 따라 향후에는 우리나라 자체 국가식품안전관리체계 평가도구를 개발하는 방안도 고려할 필요가 있다.