• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.407-409
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• 2001

도시철도 공사, 지하철 공사, 철도청 등 각각의 운영기관이 독자적으로 정보화를 추진함으로서 국가적으로 중복투자 및 예산이 낭비되고 각 시스템간 호환성이 부족하여 정보를 공유할 수 없어 비효율적인 시스템 구축이 이루어지고 있는 실정이며 표준화된 정보의 부재 및 부정확한 표준에 의한 업무의 비효율성이 가중되고 사고예방 및 신속한 복구지원을 통한 대국민 안전서비스 제공 및 열차운행의 안전성 확보에 미흡한 실정이다. 본 논문은 국내 도시철도분야를 세계적인 경쟁력을 가진 분야로 육성하고 수명주기비용(Life Cycle Cost)을 최소화 및 최적화하여 경제성을 극대화시킨 도시철도 정비유지체계 정보화 시스템의 개발 및 시범적용을 위해 정보전략계획 (ISP)을 수립하기 이전에 수행한 선행연구 결과이다.

• IE interfaces
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• v.16 no.1
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• pp.27-33
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• 2003

The maintenance cost in K Steelworks has been continuously increased in proportion to the production cost. However, there seems to be a possibility of reducing cost through the optimization of maintenance actions. The failure types of the equipment in steelworks ate various with different failure cost. Thus the failure rate and cost of each type of failures should be considered simultaneously when the optimum maintenance period is to be determined. It is considered that the equipment undergoes periodic replacement and a specified number of incomplete preventive maintenance actions are performed during a replacement period. Assuming that the time to failure follows a Weibull distribution, the parameters of the failure rate are estimated using the maximum likelihood estimation. The optimal replacement period is determined to minimize the average cost per unit time. As the result of analysis it is suggested that the existing maintenance period for a hot-rolling equipment can be extended significantly.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2432-2434
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• 2003

노내 중성자 분포 측정 설비는 원자로 내부의 중성자 분포를 측정하는 설비로서 원자로 내부를 이동하는 검출기의 구동 메커니즘 제어와 측정 데이터 취득을 위한 제어시스템이 요구된다. 이 설비는 발전소 건설 당시 도입되었던 제어시스템으로 운전되고 있으나 노후되어 디지털 제어시스템으로의 설비 개선 연구가 착수 되었다. 개발된 제어시스템은 산업표준 Programmable Logic Controller 및 소프트웨어 기반으로 설계되어 기능개선, 설계변경 및 예비품 확보에 유연하게 대처할 수 있고, 진보된 검출기 구동 메커니즘 제어와 검출기 데이터 취득 기능을 통하여 측정 작업의 완전 자동화가 가능하다. 특히, 다양한 진단 기법을 통하여 작업상황 및 설비의 상태를 파악하여 필요한 보호기능과 경보기능을 제공함으로써 설비의 안정적 운영과 정비가 편리하다. 현재 개발된 시스템은 고리1호기에 설치되어 주기적으로 노내 중성자 분포 측정 작업을 수행하고 있다.

• Journal of Applied Reliability
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• v.18 no.2
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• pp.184-191
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• 2018

Purpose: The purpose of this study is to propose a method to calculate the optimal preventive maintenance cycle of radar used in the aviation weapon system of ROKAF. Methods: A hybrid model is used to estimate the optimal preventive maintenance cycle in a system that can perform condition based predictive maintenance (CBPM) through continuous diagnosis. The failure data of the radars operating in the military were used to calculate the reliability. Results: According to the research results, the reliability threshold of the radar began to decrease after 5 flights, and decreased rapidly after 12 flights. Since the second check, costs have continued to decline. Conclusion: A method is proposed to determine the cycle of optimal preventive maintenance of radar within operational budget through modeling results between reliability limit and cost for radar. The results can be used to determine the optimal preventive maintenance cycle and frequency of various avionics equipment.

• Journal of Aerospace System Engineering
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• v.11 no.3
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• pp.39-46
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• 2017

Required military demands for high reliability of weapons systems throughout stages of life cycles as high technologies combined with weapons systems, research and development continue to drive costs upwards. However, for studies on reliability of national defense weapons systems, empirical research is limited because of a lack of interest or limitations relative to data collection. This study proposes a collection process relative to field operating specifications, based on data relative to experience and management collected by visiting vessels onsite, that operate weapons systems. In addition, after drawing the operating MTBF of the launching system for the Haeseong guided missile launcher, this study compared and analyzed that with values predicted during development and identifies parts with low operating values as compared to predicted values. Results of this study relative to maintenance support troops and weapon systems development companies will contribute to maintaining operational deployment of the launching system of the Haeseong guided weapons system.

• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.79-101
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• 2008

This study is for improvement of repair part demand forecasting method of Republic of Korea Air Force aircraft. Recently, demand prediction methods are Weighted moving average, Linear moving average, Trend analysis, Simple exponential smoothing, Linear exponential smoothing. But these use fixed weight and moving average range. Also, NORS(Not Operationally Ready upply) is increasing. Recommended method of Box-Jenkins' ARIMA can solve problems of these method and improve estimate accuracy. To compare recent prediction method and ARIMA that use mean squared error(MSE) is reacted sensitively in change of error. ARIMA has high accuracy than existing forecasting method. If apply this method of study in other several Items, can prove demand forecast Capability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.7
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• pp.679-683
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• 2016

Boilers of large-sized coal-fired power plants are being operated under very poor conditions such as continuous operation or repeating of start-up and shutdown for a stable supply of electricity. Thus periodic inspection and maintenance are required to ensure reliability of operation. The loads of existing scaffolding systems for the maintenance of boilers are concentrated in the lower parts structurally, which may cause a serial collapse of the overall scaffolding system when there are problems in some members. Therefore, in this study, a safe furnace scaffolding system is developed by dispersing the loads in the upper part, as well as minimizing the hazards of serial collapsing. In addition, for cases where the direct installation of furnace scaffolding is challenging owing to the structure of the boiler tube, a lifting system for the installation of furnace scaffolding is developed so that furnace scaffolding can be supported to secure the integrity of the power generating facility.

• Journal of Legislation Research
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• no.53
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• pp.9-59
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• 2017

Recently, the aspect of regulating the legal system in North Korea has increased in quantity and shows the improvement of the evaluation of the lack of systematic consistency in the past. North Korean legislation has been negatively criticized for its lack of function and role of the legislative body and ambiguity of the legal system. In particular, the newly adopted "Legislation Law" in relation to the revision of the legislative system of North Korea contains important and clear contents to understand the legislative system and procedures of North Korea. The contents of the "Legislation Law" can be found a glimpse of the process by which the framework and procedures of the North Korean legislative process are organized more systematically. The North Korean legislation provides legal and institutional grounds for promoting internal and external policies under the Kim jong-un's regime. North Korea is focused on the nuclear issue, so there is limited information on other areas. In light of this, the purpose of this study is to examine the legislative theory and system of North Korea, and outline the theoretical basis of North Korea's emphasis on strengthening socialist judicial life, the socialist legal system, and the state theory of socialist rule of law. In addition, it can be analysed the content of actual legal reform in light of North Korea's legislative theory and system. In the study, it will examine the legislative system of North Korea and its characteristics by examining the legislative process and legislative process of North Korea. Moreover, it can be compared the contents of the Legislative Law of China with the legislative process of the DPRK and examine its characteristics. We will look at the challenges to the legislative system in North Korea and look into the future direction of the legislation. Kim jong-un's announcement of the revised legislation until recently through the publication of the 2016 Supplementary Codes is an important data for the current state of the North Korean legislation. This is because it confirms the content of the laws and regulations already known through "Democratic Chosun(a newspaper issued by North Korea Cabinet)'s statutory interpretation." However, in the case of laws and regulations related to the North Korean political system, it is still a remnant of the lagging legislation that the announcement is delayed, or it remains undisclosed or confidential. North Korean laws are developed and changed according to the changes of the times. In particular, the contents of the maintenance of foreign investment and the foreign economic law system and related internal legal system are found to change in accordance with the development direction of the socioeconomic system. If the direction of Kim jong-un's regime is to be expanded to the path of reform and opening up in the economic sector, the revision of the related laws and regulations will accelerate. Securing the transparency and objectivity of the North Korean legislative process and procedures will help to broaden the understanding of the inter-Korean legal system and to seek institutional measures for inter-Korean integration. In the future, in-depth research on the North Korean legal system will be emphasized as a basis for ultimately forming a unified Korea's legal system.

• Journal of the Korean Institute of Gas
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• v.10 no.3 s.32
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• pp.13-19
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• 2006

As a way of improving the safety of the facilities, the risk based-inspection (RBI) was executed for the chemical facilities by using K-RBI program, which has been developed based on the API-581 based resource document (BRD). As the result of the evaluation, we found the level of the process safety management (PSM) for the applied plant, quantitative risk of the applied process, risk of static facilities and pipes, and the damage mechanism of the facilities. Thus, we could suggest a proper inspection frequency using the calculated risk of the process and the status of the facilities. The applied plant achieved a reduced inspection cost by an extension of the inspection frequency, improved productivity, improved reliability of the facilities, and a computerized history management.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.881-887
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• 2011

In this paper, age exploration of ${\bigcirc}{\bigcirc}$ anti-ship missiles which were deployed on RoKN ships were analysed using parametric estimation method. Additionally, Life distribution and failure pattern of ${\bigcirc}{\bigcirc}$ anti-ship missile were analysed by using field data such as collected inspection, fail, maintenance record for 6 years. Storage failure and MTBF of missile and components were analysed by using reliability analysis s/w Weibull++ v7. The results were compared with maintenance policy including periodic inspection and MTBF which were analysed during development phase. Finally, the suggested methodology using field data analysis of oo anti-ship missile will be applied on re-estabilishment of maintenance policy of ${\bigcirc}{\bigcirc}$ anti-ship missile for TLCSM(Total Life Cost System Management) effectively.