• Membrane and Water Treatment
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• 제8권2호
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• pp.137-147
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• 2017

A water treatment utility in South Korea operates a large system of pressurized hollow fiber membrane (PHFM) modules. The optimal selection of membrane module for the full scale plant was critical issue and carried out using Risk-based Life Cycle Cost (RbLCC) analysis based on the historical data of operation and maintenance. The RbLCC analysis was used in the process of decision-making for replacing aged modules. The initial purchasing cost and the value at risk during operation were considered together. The failure of modules occurs stochastically depending on the physical deterioration with usage over time. The life span of module was used as a factor for the failure of Poisson's probability model, which was used to obtain the probability of failure during the operation. The RbLCC was calculated by combining the initial cost and the value at risk without its warranty term. Additionally, the properties of membrane were considered to select the optimum product. Results showed that the module's life span in the system was ten years (120 month) with safety factor. The optimum product was selected from six candidates membrane for a full scale water treatment facility. This method could be used to make the optimum and rational decision for the operation of membrane water purification facility.

• 한국전자거래학회지
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• 제1권1호
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• pp.93-116
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• 1996

This study aims to develop an approach to construct IWSDB for National Defense CALS. Along with the introduction of Korean version of CALS conception, it is essential to analyze the national defense system with a new information technology for the construction of IWSDB. A long-tenn goal of CALS is to construct fully Integrated Data Environment (IDE) and establish IWSDB for the application of CALS conception to the life cycle management of weapon system. IWSDB is a set of databases that contain digital data. It supports common interface of data objects and databases throughout the life cycle management of weapon system, including design, engineering, analysis, manufacturing, operation, and logistics. etc. The goal of this study is threefold. First, we propose a right direction for the establishment of Integrated Data Environment. For the integrated database technology, we use the five schema architecture and the distributed object oriented technology that will lead to the "share of data." Second, we present the most effective IWSDB architecture for defense CALS, which will provide the efficient data sharing by business process modeling. Third, we suggest that IWSDB should be constructed based on the process which is related to the acquisition and logistics of weapon system for the national defense, and at the same time it should be implemented with GITIS for government agencies and CITIS for the industries in order to obtain the efficient data sharing.

• 전기학회논문지
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• 제56권10호
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• pp.1763-1769
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• 2007

To improve the cycle-life and efficiency of an energy storage system for HEV, a dynamic control system consisted of a switch between a battery and an ultracapacitor module is proposed, which is appropriate for mild hybrid vehicle with 42V power net. The switch can be controlled based on the status of the battery and the ultracapacitor module, and a control algorithm that could largely decrease the number of high charging current peak is also implemented. Therefore the cycle life of the battery can be improved such that it is suitable for a mild hybrid vehicle with frequent engine start-stop and regenerative-braking. Also, by maximizing the use of the ultracapacitor, the system efficiency during high current charging and discharging operation is improved. Finally, this system has the effects that improves the efficiency of energy storage system and reduces the fuel consumption of a vehicle. To verify the validity of the proposed system, this paper presented cycles test results of different energy storage systems: a simple VRLA battery, hybrid energy Pack (HEP, a VRLA battery in Parallel with Ultracapacitor) and a HEP with a switch that controlled by energy management system (EMS). From the experimental result, it was proved the effectiveness of the algorithm.

• 한국CDE학회논문집
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• 제16권3호
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• pp.197-206
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• 2011

Shipbuilding is a complex industry which contains a lot of knowledge, technology, and utilities. Hence, the necessity of the PLM (Product Life-cycle Management) system which manages life-cycle information of marine product has been increased. So, many studies related to shipbuilding PLM have been preceded, and there are some cases to be built. To implement collaboration and concurrent engineering of ship designing and manufacturing, interoperability of product data in heterogeneous system is required. Also, sharing and reusing knowledge are important for innovation of business process and productivity of enterprises. Even though many studies related interoperability of product data are going on in varies domain, the application to shipbuilding is deficient. This paper proposes a methodology for management and interconnection of BOM data based on ontology in heterogeneous PLM system of shipbuilding. Using Prot$\'{e}$g$\'{e}$-OWL, we built simple domain ontology of shipbuilding industry, and then, we integrated product information of shipbuilding BOM which is represented with different ontologies. We verified possibility of integration of shipbuilding BOM in heterogeneous PLM, using ontology.

• 품질경영학회지
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• 제40권3호
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• pp.278-285
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• 2012

Purpose: Weapon systems have the long life cycle unlike the consumer product. Thus, the reliability of weapon system is improved during the life cycle through the steady technical change. In this paper, we deal with the method of evaluating the reliability of weapon system with the field failure data. Methods: Especially, we present how to gather the field failure data and evaluate the reliability through the case of K-series weapon system. To evaluate reliability, the reliability growth model is used and the result is discussed. Results: It is steadily improved the reliability of K-series weapon system deployed from 2000 to 2004. The frequency of the failures that affect the mission is largely reduced and MTBMF(mean time between mission failure) is also improved. Conclusion: We can guess the trend of the reliability of weapon system with the field data through this study. Furthermore, it can be used to improve the reliability and make maintenance policy.

• 품질경영학회지
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• 제45권3호
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• pp.349-364
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• 2017

Purpose: The purpose of this study is to analyze quality control strengthening pilot project in development stages of weapon systems which ensures zero-defect. In order to achieve that, we propose collaboration support system between related organizations. Methods: First, we analyze how quality control methods has been developed from reviewing the preliminary study in commercial and defense industry. Then, we suggest improvement plans for quality control in defense industry and propose a pilot study which able to improve the recognized problems. Results: The results of this study ensures the participants in defense industry recognize the importance of quality control and form a consensus by sharing a case study. Finally, we propose the standardized work process by utilizing manual and manpower dispatching. Conclusion: As a result, this study clarifies the scope and role of relevant organizations to achieve the defense quality assurance in the total life cycle(TLC). Also, this paper guides the collaboration system between the relevant organization which differs from the commercial industry currently divided into development-production-quality.

• 산업경영시스템학회지
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• 제35권3호
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• pp.173-179
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• 2012

The purpose of this paper is to examine the effects on reliability of equipment or product which spends a great deal of its time in the dormant condition. Many systems experienced periods of dormancy throughout their life cycle, such as periods of operational storage where the system waits, ready for use. The design of such systems must account for how these period of dormant effects system performance. The methodology for predict and analysis was developed to support the evaluation of dormant modes of operation of systems and subsystems. For proper handling of the dormant environment, issues relating to dormant failures need to be taken into consideration from design stage of the lifecycle. Furthermore, the relevant environmental concerns that need to be taken into consideration depend on the environmental factors associated with each different target environment. This paper will look at dormant reliability, the possible dormant reliability models and the methodology on life cycle reliability which has different dormant phase.

• 한국건설관리학회논문집
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• 제8권3호
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• pp.159-167
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• 2007

항만구조물의 계획 및 설계과정에서 VE/LCC분석을 통한 최적의 경제적인 의사결정이 더욱더 요구되고 있는 추세이나, 최근의 VE/LCC 설계자료를 분석해 보면 항만구조물의 열화성능에 대한 확률적 불확실성을 고려한 포괄적인 분석은 충분히 이루어지지 않은 실정이다. 본 연구에서는 퍼지 신뢰성 이론을 도입하여 항만구조물 중 방파제의 열화성능을 평가한 후 퍼지 신뢰성 해석에 따른 생애주기 비용으로 가치를 분석할 수 있는 VE/LCC 분석 모델을 개발하였고, 분석모델의 신뢰성과 활용성을 향상시키기 위한 측면에서 실제 대상 구조물에 적용한 결과, 기존의 확정론적 방법에서 고려되지 않는 데이터의 불확실량과 주관적 가치분석을 본 연구의 퍼지론적 방법에서 보다 합리적으로 반영할 수 있었고, 가치지향적 설계대안의 선정과 생애주기비용의 평가 및 유지관리조치를 위한 예산의 분배 등에 유리한 방법으로 평가되었다.

• 한국컴퓨터정보학회논문지
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• 제19권2호
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• pp.233-241
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• 2014

본 논문에서는 "Co-word" 특허분석방법과 "기술로드맵(technique road-map)" 그리고 특허활성화 라이프 사이클그래프 및 추세분석을 활용하여 ITS(Intelligent Transportation System)의 미래녹색기술에 대해 예측한다. 분석 결과 미래의 ITS 녹색 기술 분야의 발달로 탄소배출 절감 효과가 발생하기 때문에 환경 보호에 도움을 줄 것으로 예측 되었으며, 미래의 ITS 녹색 기술은 fuel saving 분야에 대한 성장이 클 것으로 예상되었다. 또한 fuel saving 분야는 미래의 IT 기술과의 융합으로 인해 더욱 실용적인 기술 분야로 발전할 수 있을 것으로 예측 되었다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.917-920
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• 2007

우리나라의 민간투자 사업은 잦은 제도변경으로 많은 혼란을 격고 있지만, 2005년 1월 사회기반시설의 민간투자법 개정으로 공공서비스시설을 대중에게 제공할 수 있는 새로운 민간투자방식은 BTL(Build Transfer Lease)이 국내건설시장에 도입되었다. BTL사업은 계획에서 유지관리까지 사업의 수명주기 전 과정을 대상으로 포괄적 형태의 사업을 수행하는 것으로 사업자의 역할과 수행능력에 따라 사업의 성패가 좌우 된다. 따라서, 본 연구에서는 효율적인 BTL사업의 추진에 필요한 명확한 시스템 기준을 분석하여 사업수행의 정확성을 검증할 수 있는데 그 목적이 있다.