As a system complexity increases and technology innovation progresses rapidly, leasing the equipment is considered as an important issue in many engineering areas. In practice, many engineering fields lease the equipment because it is an economical way to lease the equipment rather than to own the equipment. In addition, as the maintenance actions for the equipment are costly and need a specialist, the lessor is responsible for the maintenance actions in most leased contract. Hence, the lessor should establish the optimal maintenance strategy to minimize the maintenance cost. This paper proposes two periodic preventive maintenance policies for the leased equipment. The preventive maintenance action of policy 1 is performed with a periodic interval, in which their intervals are the same until the end of lease period. The other policy is to determine the periodic preventive maintenance interval minimizing total maintenance cost during the lease period. In addition, this paper presents two decision-making models to determine the preventive maintenance strategy for leased equipment based on the lessor’s preference between the maintenance cost and the reliability at the end of lease period. The structural properties of the proposed decision-making model are investigated and algorithms to search the optimal maintenance policy that are satisfied by the lessor are provided. A numerical example is provided to illustrate the proposed model. The results show that a maintenance policy minimizing the maintenance cost is selected as a reasonable decision as the lease term becomes shorter. Moreover, the frequent preventive maintenance actions are performed when the minimal repair cost is higher than the preventive maintenance cost, resulting in higher maintenance cost.

An aircraft engine is supposed to be used for a specified lifespan, and it is reused through the depot maintenance for a major overhaul when its cumulative service life reaches the lifespan. However, the depot maintenance takes a long time due to the complexity of its process, and thus to continuously operate aircraft, spare engines are required to substitute engines under renovation. Considering the limited capacity of the depot, the uniformity of the quantity and cycle of engines entering the depot maintenance provides an opportunity to the decrease of the spare engines and the improvement of aircraft availability. It is the purpose of engine life management. Furthermore, in establishing flight plans, the time for essential maintenance activities, such as pre/post-flight inspection, servicing, the preparation for next flight, has to guarantee. Especially, fighters additionally require much time for installing weapons for their mission. That is, the rearming procedure can be left out if the adjoining missions are identical. Otherwise, the rearming time is varyingly spent depending on the types of adjacent duties. Therefore, this study proposes the mathematical model for an aircraft-mission assignment considering engine life management and maintenance schedule, and it is formulated based on the time-space network. Moreover, to verify and validate the model, an example was developed by applying realistic aircraft operating environment and simulation to perform air operations for several days was fulfilled. The experimental results presented flight plans corresponding to the purpose of this study, such as engine life management and the assurance of maintenance time.

As a system complexity increases and technology innovation progresses rapidly, it tends to lease a system rather than own one. This paper deals with a decision-making model to determine the preventive maintenance strategy for leased equipment. Various maintenance options are presented and formulated via the non-homogeneous Poisson process. During the lease period, the preventive maintenance strategy that minimizes the total cost among the presented maintenance options is selected. A numerical example is provided to illustrate the proposed model.

연안정비사업이 수행된 만성리 해수욕장에 대해 주기적으로 측량된 해빈자료와 2016년 제18호 태풍 차바 내습시 관측된 강력한 해빈 변형외력으로부터 해빈변화가 현장관측자료를 기반으로 기술되었다. 만성리 해수욕장의 해빈은 양빈 이후 3개월에 걸쳐 자연외력에 반응된 안정 화가 서서히 진행되었으나 태풍 차바에 의해 그 안정화가 깨어졌으며, 태풍내습 2개월 후부터 다시 안정적인 해빈을 나타내어 양빈 1년 후까지 큰 변화가 나타나지 않았다. 태풍 차바 내습직후 만성리 해수욕장의 해안선은 도류제가 설치된 부근해빈과 잠제의 영향이 없는 해빈북측에서 주 로 해안선이 후퇴하였고, 잠제배후역에서 해안선이 전진하였다. 또한 태풍내습직후 해빈체적이 3,395㎥ 감소하였는데, 감소한 영역은 주로 잠제의 영향이 없는 해빈북측에 집중되었으며 잠제배후의 후빈역은 오히려 퇴적되었다. 따라서 만성리 해수욕장에서 수행된 연안정비사업은 파랑에 기 인한 표사이동이 지배적인 이곳에서 해빈보존에 상당히 기여하였다.

This paper suggests a specific model that could efficiently improve the interaction and the interface between MES(Manufacturing Execution System) server and POP(Point of Production) terminal through electronic document server and electronic pen, bluetooth receiver and form paper in disassembly and process inspection works. The proposed model shows that the new method by electronic document automation system can more efficiently perform to reduce processing time for maintenance work, compared with the current approach by handwritten processing system. It is noted in case of the method by electronic document automation system that the effects of proposed model are as follows; (a) While the processing time per equipment for maintenance by the current method was 300 minutes, the processing time by the new method was 50 minutes. (b) While the processing error ratio by the current method was 20%, the error ratio by the new method was 1%.

This research focuses on the condition of the coveralls that automobile maintenance workers wear. The objective of this survey is to conduct a thorough analysis on the quality of the coveralls and put forth suggestions for improving their quality. The research data were collected through interviews and the results are as follows. The participants in this research engage in a variety of types of maintenance work including oil changes and overall system checks and they usually wear extra-large-sized coveralls. The coveralls are generally worn during the winter for warmth and the company handles all purchasing and maintenance of the work clothes. Participants mentioned that certain parts of the clothes where they bend and stretch are cumbersome and areas around the knees and arms become easily tainted. They have also reported that although the coveralls are necessary, they are for the most part dissatisfied when it comes to the materials, design, and color. The participants have suggested that new coveralls would help to increase their work efficiency. As a result, it is concluded that the coveralls require much more development to meet the workers’ needs and improvements need to be made on the functionality, aesthetics, and symbolic aspects of the design.

This research focuses on the condition of the coveralls that automobile maintenance workers wear. The objective of this survey is to conduct a thorough analysis on the quality of the coveralls and put forth suggestions for improving their quality. The research data were collected through interviews and the results are as follows. The participants in this research engage in a variety of types of maintenance work including oil changes and overall system checks and they usually wear extra-large-sized coveralls. The coveralls are generally worn during the winter for warmth and the company handles all purchasing and maintenance of the work clothes. Participants mentioned that certain parts of the clothes where they bend and stretch are cumbersome and areas around the knees and arms become easily tainted. They have also reported that although the coveralls are necessary, they are for the most part dissatisfied when it comes to the materials, design, and color. The participants have suggested that new coveralls would help to increase their work efficiency. As a result, it is concluded that the coveralls require much more development to meet the workers’ needs and improvements need to be made on the functionality, aesthetics, and symbolic aspects of the design.

정보통신기술 고도화에 따라 스마트폰, 웨어러 블 기기, IoT 등 각종 정보통신기기를 통한 개인 정보의 처리가 일상적으로 이루어짐에 따라 대용 량의 데이터를 신속하고 다양하게 분석해서 유의 미한 통찰을 도출하는 빅데이터의 활용에 대한 사 회적 관심이 증가하고 있다. 특히 빅데이터는 이 용자의 행태정보를 기반으로 개인의 취향 등 이용 자가 직접적으로 제공하지 않은 정보까지 분석함 으로써 개인화된 맞춤형 서비스의 제공에 매우 유 용할 것으로 기대되고 있다. 그러나 이와 같은 행 태정보 기반의 빅데이터 처리는 수집 사실을 이용 자가 명확히 인지하기 어렵고, 분석 결과가 이용 자가 원치않는 민감한 정보일 수 있으며, 보다 유 의미한 결과 도출을 위해 외부의 정보와 결합하는 경우 식별 가능성이 높아지는 등 이용자의 프라이 버시 침해에 대한 우려 또한 높은 실정이다. 그러나 현행 개인정보보호 관련 법률은 빅데이 터의 주요 분석 대상인 행태정보와 같은 비정형 데이터의 처리가 아닌, 성명, 주민번호, 연락처 등 의 인적사항 중심의 정형 데이터에 대한 보호조치 중심으로 규정되어 있어 빅데이터를 위한 규제로 는 적합하지 않은 부분이 많다. 특히 행태정보의 활용이 활발한 온라인 광고 플랫폼에는 인적사항 에 대한 정보는 적재되지 않아 더욱 적합하지 않 다. 이와 관하여 방통위는 온라인 광고 가이드를 배포하였으나 기존 개인정보보호 법제가 수정되 지 않는 이상 근본적인 한계가 있다. 이에 동 논문에서는 빅데이터 사회에서의 개 인정보의 보호 및 활용에 대한 조화로운 균형을 위해 세 가지의 법제 개선 방안을 제시하였다. 첫 째, 개인정보의 법적 개념 및 정의를 수정해야 한 다. 개인 식별이 분명한 인적 사항 중심의 개인정 보와 개인 식별 가능성이 거의 없거나 낮은 행태 정보로 구분하여 규정하고 각각 다른 규제 체계 를 적용해야 한다. 둘째, 행태정보를 기반으로 빅 데이터를 분석한 경우 민감한 추론의 도출을 제 한해야 한다. 셋째, 행태정보 기반의 빅데이터 분 석 및 서비스 활용에 대한 이용자의 사후 통제권 을 보장해야 한다. 고도화된 정보통신사회에서 빅데이터의 분석은 사회적 효용을 위해서 필수불 가결하지만 현행 개인정보보호 법규 체계에는 보호와 활용 어느 한 쪽도 효과적으로 대응하지 못 하고 있으므로 개인정보 보호에 대한 인식 전환 이 필요하다.

가석방은 기간을 정하지 않은(부정기의) 조건부석방제도로, 자유형의 집행 중에 있는 자가 일정한 요건을 충족하는 경우 형기가 만료되기 전에 석방하는 제도이다. 가석방은 수형자 스스로의 개선노력을 유인하고 일정한 조건하에 자율적으로 사회의 구성원으로 잘 적응하여 재범방지와 사회복귀를 돕는 것으로 재사회화라는 교정의 목적과 부합한다. 우리나라는 1953년 형법을 제정하면서 가석방제도를 채택한 이래로, 1995년 개정형법에 의해 보호관찰과 결합시킴으로써 시설내처우에서 사회내처우로 전환된 형집행의 새로운 형태로 수형자의 개선과 사회복귀에 많은 성과를 거두고 있다. 그러나 현행 가석방의 경우 높은 형집행률과 낮은 가석방률로 인하여 가석방이 활성화되지 못하고 있으며, 이는 가석방 요건과 심사가 갖고 있는 문제로부터 초래된다고 지적되고 있다. 가석방 요건에 있어서는 주로 죄질과 형량에 기초한 일률적인 가석방, 실질적 심사사항의 주관성이 문제되며, 가석방 심사와 관련하여서는 수형자의 심사신 청권, 심사기관의 이원화, 불복제도 등이 문제된다고 할 수 있다. 가석방을 활성화하기 위한 구체적인 개선방안으로 가석방 요건 중 형집행기간을 선고형에 따라 다르게 하는 등 가석방 요건을 완화함과 동시에 일정한 경우에 직권에 의한 필요적 가석방 내지 수형자의 신청에 의한 가석방심사를 인정함으로써 수형자에게 가석방심사의 기회를 보장해주고, 이원화된 가석방심사기관을 일원화 및 상임화하며, 가석방심사위원회는 수형자의 가석방결정에 대한 이의신청기관으로 재구성할 것을 제안한다.

Recently as the manufacturers want competitiveness in dynamically changing environment, they are trying a lot of efforts to be efficient with their production systems, which may be achieved by diminishing unplanned operation stops. The operation stops and maintenance cost are known to be significantly decreased by adopting proper maintenance strategy. Therefore, the manufacturers were more getting interested in scheduling of exact maintenance scheduling to keep smooth operation and prevent unexpected stops. In this paper, we proposedan integrated maintenance approach in injection molding manufacturing line. It consists of predictive and preventive maintenance approach. The predictive maintenance uses the statistical process control technique with the real-time data and the preventive maintenance is based on the checking period of machine components or equipment. For the predictive maintenance approach, firstly, we identified components or equipment that are required maintenance, and then machine parameters that are related with the identified components or equipment. Second, we performed regression analysis to select the machine parameters that affect the quality of the manufactured products and are significant to the quality of the products. By this analysis, we can exclude the insignificant parameters from monitoring parameters and focus on the significant parameters. Third, we developed the statistical prediction models for the selected machine parameters. Current models include regression, exponential smoothing and so on. We used these models to decide abnormal patternand to schedule maintenance. Finally, for other components or equipment which is not covered by predictive approach, we adoptedpreventive maintenance approach. To show feasibility we developed an integrated maintenance support system in LabView Watchdog Agent and SQL Server environment and validated our proposed methodology with experimental data.

The objective of this study is to analyze the investment adequacy of the projects implemented according to the master plan on sewerage rehabilitation at Seoul. The planned and actually implemented ratio of invested money on sewage treatment plants (STPs) to sewers were compared in two temporal periods. Though the planned ratio of investment on STPs to sewers was 50:50 (in 2009-2020) , the actual implemented ratio in 2009-2013 was 34:66. Until 2020, the greater investment ratio on STPs to sewers should be made considering the necessity of coping with stricter legal compliance on advanced treatment, stormwater treatment and so on. The priority of the planned and partially implemented projects among four STPs and at each STP was evaluated. Considering only the performance indicator of reduced load of BOD, T-N, T-P per the capacity of each STP facility, the performance among four STPs was shown as Jung-Rang>Tan-Cheon>Seo-Nam>Nan-Ji. The reverse order of the performance results in the past may be considered for future investment priority, but the efficiency of operation implemented at each STP, deteriorated status of each STP, investment in the past and so forth should also be considered. As for the priority of projects conducted within each STP, projects related to legal compliance (such as advanced tertiary treatment, stormwater treatment, etc.) have highest priority. Odor-related project and inhabitant-friendly facility related projects (such as building park on STPs, etc.) has lower priority than water quality related projects but interactivity with end-users of sewerage should also be important.

진안의 대표적 관광지인 마이산 북부는 여러 개발 사업이 이루어지고 있으나, 종합적 개발계획이 필 요하고, 특히 기존 주차장부지와 상가지구를 대상으로 새로운 계획을 수립해야 할 시점이다. 본 연구에서는, 먼저, 마이산 북부지구를 대상으로 개발 관련 문헌조사와 현장조사를 통하여 현황 분석을 하였고, 개발 잠재력 및 장단점분석을 하였다. 이를 바탕으로, 마이산 북부지구의 전체적인 공간구성 개선방향에 대하여 제시하였고, 세부적으로 마이산 북부지구 중 이전 계획이 수립된 북부주차장 및 상가지구에 대 한 계획안으로 생태복원공원계획과 생활사전시관 및 명인명품전시관을 제시하였다.

진안의 대표적 관광지인 마이산 북부는 여러 개발 사업이 이루어지고 있으나, 종합적 개발계획이 필 요하고, 특히 기존 주차장부지와 상가지구를 대상으로 새로운 계획을 수립해야 할 시점이다. 본 연구에서는, 먼저, 마이산 북부지구를 대상으로 개발 관련 문헌조사와 현장조사를 통하여 현황 분석을 하였고, 개발 잠재력 및 장단점분석을 하였다. 이를 바탕으로, 마이산 북부지구의 전체적인 공간구성 개선방향에 대하여 제시하였고, 세부적으로 마이산 북부지구 중 이전 계획이 수립된 북부주차장 및 상가지구에 대 한 계획안으로 생태복원공원계획과 생활사전시관 및 명인명품전시관을 제시하였다.

A CCTV inspection method has been widely used to assess sewer condition and performance, but Korea lacks a proper decision support system for prioritizing sewer repair and rehabilitation (R&R). The objective of this paper is to introduce the results that we have developed in the Sewer Condition Assessment and Rehabilitation Decision-making (SCARD) Program using MS-EXCEL. The SCARD-Program is based on a standardized defect score for sewer structural and hydraulic assessment. Priorities are ranked based on risk scores, which are calculated by multiplying the sewer severity scores by the environmental impacts. This program is composed of three parts, which are decision-making for sewer condition and performance assessment, decision-making for sewer R&R priority assessment, and decision-making for optimal budget allocation. The SCARD-Program is useful for decision-makers, as it enables them to assess the sewer condition and to prioritize sewer R&R within the limited annual budget. In the future, this program logic will applied to the GIS-based sewer asset management system in local governments.

In order to manage essential parts that are required for the repairable parts services performed at the military maintenance depots, the United States Air Force developed the Repairability Forecasting Model (RFM). In the RFM, if the requirements of the parts are assumed to follow the normal probability distribution after applying means from the past data to the replacement rate and lead times, the chance of the AWP (Awaiting Parts) occurring is 50%. In this study, to counter the uncertainties of requirements and lead times from the RFM, the safety level concept is considered. To obtain the safety level for requirements, the binomial probability distribution is applied, while the safety level for lead time is obtained by applying the normal probability distribution. After adding this concept, the improved RFM is renamed as the ARFM (Advanced RFM), and by conducting the numerical stimulation, the effectiveness of the ARFM, minimizing the occurrence of the AWP, is shown by increasing the efficiency of the maintenance process and the operating rate of the weapon system.