• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2724-2731
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• 2014

As the future national defense plan of government focus on advanced weapon system, military maintenance facility becomes more important. However, military maintenance facility has been managed by director's experience and simple mathematical calculation until now. Thus, the optimization for the management of military maintenance facility is suggested by more scientistic and logical methods in this study. The study follows the procedure below. First, simulation is designed according to the analysis of military maintenance facility. Second, independent variable and dependent variable are defined for optimization. Independent Variable includes the number of maintenance machine, transportation machine, worker in the details of military maintenance facility operation, and dependent variable involves total maintenance time affected by independent variable. Third, warmup analysis is performed to get warmup period, based on the simulation model. Fourth, the optimal combination is computed with evolution strategy, meta-heuristic, to enhance military maintenance management. By the optimal combination, the management of military maintenance facility can gain the biggest effect against the limited cost. In the future, the multipurpose study, to analyze the military maintenance facility covering various weapon system equipments, will be performed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.335-338
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• 2023

국방 무기체계의 운용유지를 위해서는 숙련자에 의한 신뢰성있는 정비 지원이 필요하다. 특히, 고도의 기술력을 바탕으로 연구/제작된 해군 무기체계를 유지하기 위해서는 이와같은 정비 지원이 무엇보다 중요하다. 해군에서는 효과적인 정비지원을 위해 수개의 정비지원부대를 조직하여 운용하고 있다. 원활한 정비지원부대의 운용을 위해 다년간 기술력을 축적한 정비인원의 중도 이탈을 예방하는 것이 요구되므로, 본 논문에서는 머신러닝을 적용하여 해군 정비지원부대의 퇴직자 예측 모델을 제안하였다. 정비인력의 만족도와 관계가 있을 것으로 예상되는 봉급, 특근율 등을 변수로 사용하였고, F1 Score를 통해 모델의 성능을 평가한 결과 0.7이상의 높은 성능을 보였다. 이 모델을 통해 조기 퇴직이 예상되는 그룹의 공통 개선소요를 파악하여 사전 조치가 가능할 것으로 판단하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.125-132
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• 2012

Busan metropolitan city faced with very low completion rate of residential environment improvement projects. Main reason is to designate proposed residential environment improvement areas without careful analysis of the possibilities of the improvement project completion. This study aims to clarify and analyze the phase characteristics of residential environment improvement process by using 12 variables representing 5 locational characteristics such as place factors, topological factors, size factors, location condition factors and regulation factors. From results of the analysis, this study finds that business floor area ratio, improvement type and site size affect significantly the completion rate of residential redevelopment projects. However, business floor ratio, improvement type, width of frontage road and slope are significant variables to affect the completion rate of residential rebuilding projects.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.263-269
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• 2012

Condition-based maintenance (CBM) has been used as a useful concept for optimizing maintenance plan and decreasing maintenance cost in several kinds of plant sites. This study introduced an example that developed an integrated management system for maintenance parameters and hydraulic turbine of hydro-power plant in order to improve its maintenance system as applying CBM techinique. The integrated management system consists of three parts. One is a hardware part including PDA inspection system and several kind of precision measuring instruments. Another is a vibration monitoring system on hydraulic turbine. The other is a software part that takes charge of making hierarchy tree of maintenance parameters and their inspection route, managing accumulated database, assessing health condition of components, and supporting interface with other enterprise management system. The system has been installed at Chuncheon Hydro-power plant for test and demonstration. It is expected that the system can contribute database construction for diagnostics and prognostics on facility health condition and systematic accumulation of know-how on operation and maintenance of plant.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.574-581
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• 2012

Condition-based maintenance(CBM) has been used as a useful concept for optimizing maintenance plan and decreasing maintenance cost in several kinds of plant sites. This study introduced an example that developed an integrated management system for maintenance parameters and hydraulic turbine of hydro-power plant in order to improve its maintenance strategy as applying CBM techinique. The integrated management system consists of three parts. One is a hardware part including PDA inspection system and several kind of precision measuring instruments. Another is a vibration monitoring system on hydraulic turbine. The other is a software part that takes charge of making hierarchy tree of maintenance parameters and their inspection route, managing accumulated database, assessing health condition of components, and supporting interface with other enterprise management system. The system has been installed at Chuncheon hydro-power plant for test and demonstration. It is expected that the system can contribute database construction for diagnostics and prognostics on facility health condition and systematic accumulation of know-how on operation and maintenance of plant.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.48-48
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• 2003

가스터빈 핵심부품은 모두 고온고압의 열악한 환경에서 사용되므로 정기적으로 열화상태를 파악하여 신품으로의 교체 또는 재생 정비해야 한다. 그러나 국내의 재생 정비기술의 낙후로 인해 재생 가능한 고가의 부품까지 폐기, 교체함으로써 발전원가 상승의 주 요인이 되고 있다. 본 연구에서는 발전용 GT 블레이드 재료인 IN738LC 및 GTD111 판상시편에 대하여 다양한 용접 방법과 변수로 PTA 육성용접하였으며, 각 변수에 따른 미세조직 변화를 관찰하고 모의결함 시편에 대해 기계적 물성을 평가하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.257-262
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• 2008

This study presents a detailed analysis of aircraft engine maintenance cost based on the relationships between engine performance and geometric parameters. Some trend equations based on the engine performance and maintenance database were developed for the estimation of shop-visit interval, work-scope, man-hours, material cost and Life Limited Part cost. The results show that this approach can give a more reasonable and detailed estimation of engine maintenance cost than older empirical methods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.2135-2146
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• 2013

Most researches about residential improvement projects deal with different process phase in order to examine important affecting variables. The main purpose of this study is to identify influential change of locational variables according to the process of residential improvement projects. Generally the residential improvement project consists of four phases such as site designation, project committee approval, residents association establishment and final project approval. The discriminant and correlation analyses are employed to examine the changes of locational variables by each phase of the project process. In residential redevelopment projects, the finding shows that locational variables in the final project approval phase act differently from those in the other phases. On the other hand, the variables act similarly among the four phases in the case of residental rebuilding projects although the significant level of discriminant analysis result, in the site destination phase, is relatively low significance. Therefore, there is no difference among the project process phase to examine to what extent of the residential improvement projects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.337-347
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• 2018

The government has been operating residential improvement projects through the "Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents" as a type of a remedial measure for deteriorated residential areas. However, in recent years, the residential improvement projects have experienced difficulties due to the effects of various factors including the slowdown in economic growth. After observing the depression in a number of projects, various studies have been carried out to investigate the causality and improve the promotion of the residential improvement projects. In the trend of research, this study aims to analyze the effects of land and building characteristics on the improvement projects of Busan Metropolitan City. The dependent variables of the study represent different phases of improvement project as specified in the "Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents". The independent variables represent land and building characteristics which refer to the criteria used in the designation process of maintenance area according to the act. The empirical analysis uses the ordered logit model. The results from the analysis suggest that geographical condition, factors related to the number of union members, factors related to the parcel price and condition of a location have impact on the promotion of the improvement project. The results of the analysis show that majority of the factors are related to the economic feasibility of the projects. Residential improvement project is a part of urban planning projects that rehabilitates deteriorated residential environment, and it is closely associated with the quality of life of public. Accordingly, we hope that such projects are reasonable and take effective approach to those with urgent needs rather than to focus on profitability. Also, potential administrative and economical loss should be avoided by taking necessary planning measures in advance.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.859-866
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• 2022

Active disturbance rejection control is a method in which the disturbance is removed from the controller by estimating the state variable using the Luenberger observer. The Luenberger observer is estimated by defining a nonlinear term including disturbance with constant characteristics in a steady state as a state variable. It can be shown that the speed tracking performance is improved by compensating the estimated state variable to the PI controller and the IP controller. The disturbance removal performance of the tracking control can be confirmed by observing that the estimated state error is within 1.9 [%] in the case of load fluctuation and the steady-state state tracking error converges to zero.