• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.561-566
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• 2008

The EMU of maintenance technique or system is changing on a large scale. To subway operation beginning the breakdown was born and every that time after the fact repaired. But, recently before the breakdown of the subway occurs, repairs in advance with the preventive maintenance concept which was exchanged. However, the preventive maintenance is to readjust, cleaning, tighten and the oil the repetition by the worker simple experience. This study on introduces the EMU of maintenance method which applies a automatic inspection equipment from the study contributing which develops the preventive maintenance system.

• 한국정보통신학회논문지
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• 제23권7호
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• pp.869-874
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• 2019

노화에 의한 시스템의 예기치 않은 장애 발생은 예방 관리 기능을 수행함으로써 줄일 수 있으며, 이를 통해 시스템의 가용도를 높일 수 있다. 예방 관리 기법은 크게 시간 기반과 조건 기반의 두 가지로 나눌 수 있다. 시간 기반 방식은 정해진 시간 간격마다 수행되고, 조건 기반 방식은 시스템 상태가 특정 조건을 만족할 때 수행된다. 조건 기반 방식은 시간 기반 방식과 비교했을 때 예방 관리의 효율성을 향상시킬 수 있다는 장점이 있다. 본 논문은 노화 상태에서 일정 시간이 지난 후 예방 관리를 수행하게 되는 시스템을 분석할 수 있는 확률 모형을 제시한다. 제시한 모형은 현실적인 상황을 반영하여 비 마르코비안 모형으로 모델링한다. 해당 확률 모형을 수학적으로 해석하여 정상 상태에서의 시스템 가용도와 수익을 분석한다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권9호
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• pp.1397-1406
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• 2019

Objective: Feed energy required for pigs is first prioritized to meet maintenance costs. Additional energy intake in excess of the energy requirement for maintenance is retained as protein and fat in the body, leading to weight gain. The objective of this study was to estimate the metabolizable energy requirements for maintenance ($ME_m$) by regressing body weight (BW) gain against metabolizable energy intake (MEI) in growing pigs. Methods: Thirty-six growing pigs ($26.3{\pm}1.7kg$) were allotted to 1 of 6 treatments with 6 replicates per treatment in a randomized complete block design. Treatments were 6 feeding levels which were calculated as 50%, 60%, 70%, 80%, 90%, or 100% of the estimated ad libitum MEI ($2,400kJ/kg\;BW^{0.60}\;d$). All pigs were individually housed in metabolism crates for 30 d and weighed every 5 d. Moreover, each pig from each treatment was placed in the open-circuit respiration chambers to measure heat production (HP) and energy retained as protein ($RE_p$) and fat ($RE_f$) every 5 d. Serum biochemical parameters of pigs were analyzed at the end of the experiment. Results: The average daily gain (ADG) and HP as well as the $RE_p$ and $RE_f$ linearly increased with increasing feed intake (p<0.010). ${\beta}$-hydroxybutyrate concentration of serum tended to increase with increasing feed intake (p = 0.080). The regression equations of MEI on ADG were MEI, $kJ/kg\;BW^{0.60}\;d=1.88{\times}ADG$, g/d+782 ($R^2=0.86$) and $ME_m$ was estimated at $782kJ/kg\;BW^{0.60}\;d$. Protein retention of growing pigs would be positive while REf would be negative at this feeding level via regression equations of $RE_p$ and $RE_f$ on MEI. Conclusion: The $ME_m$ was estimated at $782kJ/kg\;BW^{0.60}\;d$ in current experiment. Furthermore, growing pigs will deposit protein and oxidize fat if provided feed at the estimated maintenance level.

• International Journal of Reliability and Applications
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• 제11권2호
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• pp.69-87
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• 2010

The optimal replacement problem was investigated for a multi-state deteriorated system for which the true internal state cannot be observed directly except when the system breaks down completely. The internal state was assumed to be monitored incompletely by a monitor that gives information related to the true state of the system. The problem was formulated as a partially observable Markov decision process. The optimal procedure was found to be a monotone procedure with respect to stochastic increasing ordering of the state probability vectors under some assumptions. Limiting the optimal procedure to a monotone procedure would greatly reduce the tremendous amount of calculation time required to find the optimal procedure.

• International Journal of Railway
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• 제1권2호
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• pp.59-63
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• 2008

The maintenance effect is a peculiar factor applied to repairable systems such as rolling stocks. Conventional statistical analysis for failure times takes into account one of the two following extreme assumptions, namely, the state of the system after maintenance is either as "good as new" (GAN, perfect maintenance model) or as "bad as old" (BAO, minimal maintenance model). Most of the papers concerning the stochastic behavior of railroad systems assume two types of maintenance: perfect and minimal maintenance. However, Lee, Kim & Lee (2008) analyzed the failure data of a door system in Metro EMU and the effect of preventive maintenance was imperfect. It is seen that the imperfect maintenance is of great significance in practice. This article describes how to deal with the maintenance effect in reliability studies of rolling stocks. Maintenance policies under imperfect maintenance are described and the method is proposed to evaluate their performance.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.260-264
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• 2005

This paper gives a basic information of live line maintenance technique of UHV T/L and introduce a technical background and trends of domestic and abroad. The importance of live line maintenance technology getting increased because the change of power system environment and maintenance conditions in korea. this paper explain the present state of the development of live line maintenance technique in korea and show a difference with advanced countries.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.328-330
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• 2007

Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. The state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect Maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

• Tuberculosis and Respiratory Diseases
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• 제76권1호
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• pp.1-7
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• 2014

Maintenance therapy has emerged as a novel therapeutic paradigm for advanced non-small-cell lung cancer (NSCLC). Maintenance therapy that aims to sustain a clinically favorable state after first-line chemotherapy has two strategies. Switch maintenance therapy entails switching to a new and non-cross-resistant agent in an alternating or sequential manner, on completion of first-line chemotherapy. Continuous maintenance therapy keeps ongoing administration of a component of the current regimen after four to six cycles of chemotherapy, if there is a stable disease, or better response. Both maintenance therapies can be continued, until disease progression. The potential evidence regarding maintenance therapy includes providing the opportunity to receive additional treatment, through sustaining tumor shrinkage, and delayed emergence of tumor-related symptom. Thus far, debates over the parameters used to predict the effectiveness of maintenance therapy, financial burden, and uncertainty of improving the quality of life exist. Despite many debates, maintenance therapy, which is currently recommended, has been disclosed to be beneficial.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1807-1813
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• 2018

In this paper, the fault line selection and location problems of single line-to-ground (SLG) fault in distribution network are addressed. Firstly, the adaptive filtering property for empirical mode decomposition is formulated. Then in view of the different characteristics showed by the intrinsic mode functions(IMF) under different fault inception angles obtained by empirical mode decomposition, the sign of peak value about the low-frequency IMF and the capacitance transient energy is chosen as the fault line selection criteria according to the different proportion occupied by the low-frequency components. Finally, the fault location is determined based upon the comparison result with adjacent fault passage indicators' (FPI) waveform on the strength of the interaction between the distribution terminal unit(DTU) and the FPI. Moreover, the logic nodes regarding to fault line selection and location are newly expanded according to IEC61850, which also provides reference to acquaint the DTU or FPI's function and monitoring. The simulation results validate the effectiveness of the proposed fault line selection and location methods.

• Journal of Platform Technology
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• 제8권4호
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• pp.3-10
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• 2020

승강기 유지보수 업체는 다양한 종류의 승강기 유지 보수를 담당하고 있어 승강기 제조사, 승강기 모델에 독립적인 승강기 원격 관제 시스템이 필요하다. 이를 위해 각 승강기에서 수집된 승강기 운행 데이터를 수신하여 데이터베이스에 전송할 수 있는 데이터 수집기가 필요하다. 본 논문에서는 중소 규모의 승강기 유지 보수 업체에서 활용할 수 있는 원격 관제 시스템의 데이터 수집기를 설계, 구현한다. 데이터 수집기는 승강기의 운행 상태를 전송하는 센서 모듈이 전송한 데이터 패킷을 수신하여, 데이터를 해석, 변환한 후 자체 개발한 API 를 이용하여 서버로 전송을 한다. 본 논문에서는 파이썬으로 구현한 데이터 수집기에 대해 기술하고, 실 운행 환경에 있는 승강기에 설치된 센서 모듈에서 전송한 데이터를 수신하고, API 서버로 전송하는 것을 화면에 표시된 로그를 통해 보인다.