• 응용통계연구
• /
• 제26권1호
• /
• pp.151-162
• /
• 2013

중고제품 특히 고가인 중고품에 대한 점증하는 수요로 인하여 그러한 제품에 대한 보증과 보전정책이 최근 제품의 신뢰성을 향상시키기 위해 연구되고 있다. 이 논문에서는 사용한 년 수 x에서 고객에 의해서 구입된 중고제품에 대한 주기적인 유지보수모형을 연구하였다. 구입할 때 판매자는 제품의 고장율을 줄이기 위해서 그리고 각각의 유지보수가 수행되고 난 이후에 신뢰성을 향상시키기 위해서 정해진 보증기간을 제공한다. 만일 연속적인 유지보수 사이에서 고장이 일어난다면 단지 최소수리가 행해진다. 보증정책에 대해서 보증기간동안에 주기적인 유지보수 점검과 더불어 각 고장에 관해서는 무상 비재생수리를 한다. 따라서 이러한 보증정책 하에서 보증기간에 일어난 모든 유지보수와 수리비용은 판매자에게 부과된다. 제안된 주기적인 유비보수 계획에 대해서 보증기간 동안에 판매자에게 부과된 기대 총비용을 계산하기 위한 모형과 판매자의 측면에서 총기대보증비용을 최소화하기 위한 각 유지보수에서 고장율의 최적향상수준을 유도한다. 또한 제안된 방법들에 근거해서 최적향상수준에 대한 수치적인 결과를 제시한다.

• 대한산업공학회지
• /
• 제25권1호
• /
• pp.47-55
• /
• 1999

This paper develops an efficient heuristic algorithm for scheduling workforce level that can accommodate all the requested maintenance jobs. Each job has its own release and due dates as well as man-day requirement, and must be scheduled in a non-interrupted time interval, namely, without preemption. Duration of each job is not fixed, but to be determined within given specific range. The objective is to minimize workforce level to complete all the requested maintenance jobs. We show that the problem can be seen as a variant of the two-dimensional bin-packing problem with some additional constraints. A non-linear mixed integer programming model for the problem is developed, and an efficient heuristic algorithm based on bin-packing algorithms is proposed. In order to evaluate goodness of the solution obtained from the proposed algorithm, a scheme for getting a good lower bound for the optimum solution is presented and analyzed. The computational experiment shows that the proposed algorithm performs quite satisfactorily.

• 한국항공운항학회지
• /
• 제18권2호
• /
• pp.46-53
• /
• 2010

In the aspect of the nature of aircraft maintenance work on divisible tasks carried out by a wide range of operation and expertise, any information transmission problems will not only cause a threat to flight safety but also reduce productivity by keeping the team from fulfilling its mission of delivering aircraft with airworthiness. In this regard, this study firstly identify the current status of information of aircraft maintenance and factors disturbing information transmission. Then, this article also find out the level of information culture of the AMT(Aircraft Maintenance Technicians) and problems in using information. Finally, suggestions on the model of the positive information culture in a field of aircraft maintenance through efficient use of the information including safety will be followed.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
• /
• pp.72-73
• /
• 2019

As the physical functions of school buildings and the changes in the functions of educational facilities due to social change are increasing, the demand for fundamental and long-term measures for the maintenance of educational facilities is expanding. However, depending on the function of the facility, the maintenance work has been carried out only when it is directly related to the safety problem, or when the request of the school facility manager is requested, rather than supporting preventive maintenance. In this study, we investigate the maintenance process of educational facilities and propose a method to manage the maintenance process of the educational facilities in the unit of space for establishing an efficient maintenance management system.

• 디지털융복합연구
• /
• 제8권1호
• /
• pp.1-10
• /
• 2010

2004년부터 정부는 기존 산업의 고도화를 위해 RFID/USN활용 지원사업을 단계적으로 추진해 왔다. 최근들어 일부 대기업을 중심으로 RFID/USN활용 성과들이 확인되고 있으나, 추가적인 산업정책 및 지원을 위한 기본적인 정책 자료가 부족한 실정이다. 이에 2008년도 시행된 27개의 시범사업을 대상으로 실 수혜기관의 만족도를 조사하여 RFID/USN의 구축단계, 활용단계(기술적 품질), 활용단계(업무적 품질), 그리고 유지보수단계 등 4단계에서의 만족도를 평가하고, 시사점을 도출하고자 하였다. 연구 결과, RFID/USN 기술의 안정성은 상당한 수준에 도달하였으나. 활용 및 확산을 위한 유지보수단계의 만족도가 가장 낮게 나타났다. 정책적 시사점으로 태그 및 기기의 저렴한 제공, 서비스 신뢰성 및 지속성을 위한 유지보수 컨소시엄 구성, RFID/USN 활용을 위한 수혜기업의 내부역량 강화 등 RFID/USN 유지보수 단계의 구체적인 정책지원등을 제시하였다.

• 한국IT서비스학회지
• /
• 제14권3호
• /
• pp.67-84
• /
• 2015

Software is more diverse and complex and the level of importance for the maintenance of application software to securely operate software is also gradually increasing in proportion. The calculation method for maintenance cost of application software applied in Korea public enterprises is involved in the range of 10 to 15% of development cost, depending on the Software Project Cost Estimation Guide. Moreover, as most software maintenance cost estimation procedures do not take into consideration of the risk factors related of maintenance, it can be seen as a main cause for the occurrence of maintenance related accidents. This study proposes a maintenance cost estimate model that takes into consideration of the risks related to the software maintenance activities to improve and resolve issues arising from the estimation of maintenance cost. In doing so, maintenance risk factors are analyzed and a risk index is derived through the analysis of risk levels based on the risk factors. Based on such analysis, a maintenance cost estimate method which reflects the maintenance risk index was established.

• 품질경영학회지
• /
• 제29권3호
• /
• pp.39-48
• /
• 2001

Preventive maintenance(PM) is an action taken on a repairable system while it is still operating, which needs to be carried out in order to keep the system at the desired level of successful operation. In this paper, we consider a Bayesian approach to determine an optimal periodic preventive maintenance policy. When the failure time is Weibull distribution with uncertain parameters, a Bayesian approach is established. Some numerical examples are presented for illustrative purpose.

• 한국강구조학회 논문집
• /
• 제18권6호
• /
• pp.677-686
• /
• 2006

본 논문에서는 생애주기비용뿐만 아니라 생애주기성능 조건을 함께 고려하여 열화되는 교량의 최적 유지관리 전략 수립을 위한 보다 실제적이고 현실적인 방법을 제안하였다. 교량의 성능 및 비용과 관련된 다중목적 조합 최적화 문제인 교량 유지관리 시나리오 집합의 생성을 위해 유전자 알고리즘을 적용하였으며, 다중목적함수에 대한 최적의 균형 잡힌 유지관리 시나리오의 선정이 가능한 기법을 제안하였다. 최적 유지관리 시나리오는 부재수준뿐만 아니라 교량 시스템 수준에서도 생성 가능하도록 하였다. 실제 공용중인 교량에 적용하여 제안된 방법의 실 적용성을 검증하고 분석하였다. 제안된 방법은 기존의 유지관리방법의 한계를 극복하고, 실질적인 예방유지관리체계의 도입을 위한 교량 유지관리 의사결정에 활용될 수 있을 것으로 기대된다.

• The Journal of Korean Physical Therapy
• /
• 제1권1호
• /
• pp.15-25
• /
• 1989

The purpose of this study was to determine the factors influencing the standing balance of independent ambulatory hemiparetic patients. The subjects of this study were 30 hemiparetic patients (18 males, 12 females) being treated as admitted or out patients at Severance Hospital Medical Center, all of whom agreed to participate in the study. In order to assure the statistical significance of the results, the paired t-test aid a Pearson's correlation were applied at the .05 level of significance. The results were as follows. 1. The difference in maintenance time of standing balance on a stable and unstable support surface was significant at the .05 level. 2. The difference in maintenance time of standing balance according to the control of visual and acoustic stimuli was significant at the .05 level. 3. The presence or absence of passive joint motion sense influenced the standing balance maintenance time. 4. There was no significant difference in the maintenance standing balance of the sound tower leg standing conditions according to spasticity, but the paretic lower leg standing conditions were significantly different (p<.05). This type of evaluation should be more widely used in the field of evaluating standing balance with hemiparetic patients. However, more extensive study and reports on various factors of standing balance are needed.

• 상하수도학회지
• /
• 제29권3호
• /
• pp.305-317
• /
• 2015

The function failure of present major facilities is likely to lead to failure of related systems and/or whole facilities, increasing the necessity for protection of infrastructures, main structures, and major industrial facilities. In addition, safe and efficient management for urban infrastructure (waterworks and sewerage facilities, electricity, telecommunications, roads, etc) installed in the basement or on large cities grounds at various public areas is required. Recently in response to this demand, efforts for vitalizing asset management are being made such as enacting related laws and developing asset management system in the U.S., Australia, Europe and other advanced countries with the concept for a new maintenance. In our county, identifying maintenance system problems such as aging and rapid increasing of existing infrastructures and decision-making about updating maintenance is required for systematic and organizational maintenance. In this study, by comparing and observing the LOS(Level of Service) of each countries' waterworks and risk-based LOS, we suggest the direction of future urban water infrastructure management systems for more effective management.