• Journal of Construction Engineering and Project Management
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• v.3 no.3
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• pp.23-34
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• 2013

As climate change and environmental pollution become one of the biggest global issues today, new renewable energy, especially solar photovoltaic (PV) system, is getting great attention as a sustainable energy source. However, initial investment cost of PV system is considerable, and thus, it is crucial to predict electricity generation accurately before installation of the system. This study analyzes the loss ratio of solar photovoltaic electricity generation from the actual PV system monitoring data to predict electricity generation more accurately in advance. This study is carried out with the following five steps: (i) Data collection of actual electricity generation from PV system and the related information; (ii) Calculation of simulation-based electricity generation; (iii) Comparative analysis between actual electricity generation and simulation-based electricity generation based on the seasonality; (iv) Stochastic approach by defining probability distribution of loss ratio between actual electricity generation and simulation-based electricity generation ; and (v) Case study by conducting Monte-Carlo Simulation (MCS) based on the probability distribution function of loss ratio. The results of this study could be used (i) to estimate electricity generation from PV system more accurately before installation of the system, (ii) to establish the optimal maintenance strategy for the different application fields and the different season, and (iii) to conduct feasibility study on investment at the level of life cycle.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.638-645
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• 2007

Computers are increasingly being introduced into safety and reliability critical systems. The safe and reliable operation of these systems cannot be taken for granted. Malfunctions of these systems can have potentially catastrophic consequences and they have already been involved in serious accidents. Software fault prevention, fault tolerance, fault removal and fault forecasting are the techniques to be used, implemented and verified for embedded software in critical systems as the contributors to safety and reliability of the software. To use them when developing a software product, a relationship must be established between them and the development processes, the methods and techniques to be used to develop software, as well as with the different product architectures. Railroad signaling system software is a safety-critical embedded software with realtime and high reliability requirements. The primary purpose of the safety management is to prevent the loss of lives or physical damages arising from potential hazards in the railroad signaling system. This study provides a systematic approach to analysis of potential hazards for their management during the system life cycle to assure the identification and definition of the most appropriate hazards.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.212-219
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• 2012

This study focus on what methods of MOT are needed and utilized to solve a technical problem in the MOT leading company. We first classified the MOT methods by project life cycle and R&D job quality based on the several discussion with working group. In order to study, the survey was carried out by 168 experts working on MOT practices. Our main research findings are as follows. The level of utilized MOT methods was above average because MOT sector was beginning to represent an increasing share of total R&D business. But the satisfaction level on the MOT majors was below average. The more utilized MOT methods in practices were 'environment analysis and opportunity research,' 'business feasibility,' 'roadmapping,' 'portfolio,' 'technology tree,' 'scheduling,' 'risk management,' 'six sigma,' 'design of experiment,' 'quality control,' 'cost analysis' etc. And the subjects of product realization process were also needed to MOT practice such as 'design for reliability,' 'design for cost,' 'design for performance,' 'design for safety' deeply involved to product quality. Finally, the capability requested to University students were 'problem define and solving,' 'technology planning and strategy,' 'creative thinking.'

• Journal of Korean Society for Quality Management
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• v.39 no.4
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• pp.507-515
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• 2011

MIL-HDBK-217 has played a pivotal role in reliability prediction of electronic equipments for more than 30 years. Recently, RIAC developed a new methodology $217Plus^{TM}$which officially replaces MIL-HDBK-217. Sensitivity analysis of the 217Plus component models to various parameters has been performed and meaningful observations have been drawn in this study. We first briefly reviewed the $217Plus^{TM}$ methodolog and compared it with the conventional model, MIL-HDBK-217. We then performed sensitivity analysis $217Plus^{TM}$ component models to various parameters. Based on the six parameters and an orthogonal array selected, we have performed indepth analyses concerning parameter effects on the model. Our result indicates that, among various parameters, operating temperature and temperature rise during operation have the most significant impacts on the life of a component, and thus a design robust to high temperature is the most importantly required. Next, year of manufacture, duty cycle, and voltage stress are weaker but may be significant when they are in heavy load conditions. Although our study is restricted to a specific type of diodes, the results are still valid to other cases. The results in this study not only figure out the behavior of the predicted failure rate as a function of parameters but provide meaningful guidelines for practical applications.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.431-436
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• 2005

In this paper, we design and implement modules for disk backup using the backup devices in SAN clusters. The proposed backup modules provide device management features that manage a number of backup devices and groups backup devices into logical units called pools in SAN clusters. It also supports pre/post script to process additional actions for users during backup and restore processing, and provides life cycle management for backup data.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.638-641
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• 2006

In this paper, A calculating cost method of maintenance and repair for bridge which is built up by new construction technique named Up-Down Precast Concrete(UDPSC). After 2000, 109 Bridges which are using UDPSC technique have been built up, 37 bridges's construction work are processing, and 194 designs are presented for construction. Because this technology has developed recently, there are few field data for analyzing the maintenance and repair cost. Therefore, the maintenance and repair cost is computed using Construction and Transportation Ministry's guide line for computation and former research's data.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.221-238
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• 2015

Purpose: In this study, A reliability assurance model (or reliability program) is proposed to evaluate the reliability of an armed vehicle. The reliability assurance is performed through the reliability-centered activities during its life cycle of development/design, production, deployment, maintenance, and disposal. Methods: By reflecting the current situations of korea defense industry, a reliability assurance model is built up based on the benchmarking results of world leading companies' best practices in same fields. Results: The proposed reliability program of armed vehicles, which is based on the reliability program of ANSI/GEIA-STD 0009, uses DMAIC process of the six sigma methodology from design phase to testing and evaluation phase. Conclusion: This research is supposed to develop reliability program of armed vehicles by integrating DFSS, DFR and reliability growth process.

• Journal of Korean Society for Quality Management
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• v.41 no.3
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• pp.395-404
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• 2013

Purpose: Technology readiness assessment(TRA) used as a standard readiness assessment tool in the acquisition program of weapon system has some limitations in the comprehensive understanding of the complex system. Therefore, this research is intended to suggest a holistic maturity assessment method for the acquisition of high quality weapon system. Methods: Technology readiness level(TRL), manufacturing readiness level(MRL), integration readiness level(IRL) and system readiness level(SRL) developed to assess system maturities in the various aspects are compared and analyzed to draw an improvement avenue for the current readiness assessment method. Results: TRL, MRL, IRL and SRL have large differences in their maturity targets during the acquisition life cycle: technological performance, manufacturing capability, interface between components and total system, respectively. They complement one another's shortcomings Conclusion: To achieve a successful acquisition of high quality weapon system, multi-dimensional readiness assessment is required. Therefore, comprehensive readiness assessment using TRL, MRL, IRL and SRL will contribute to the acquisition of high quality weapon system through the accurate maturity information of overall system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.311-314
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• 2001

The Military made an investment continuously in facilities construction since the Korea War but, a lot of Military-Facilities Construction have overlooked a long terms plan and detailed examination. The deteriorated facilities that becomes more than about 20 years of the military possession facilities is account about $25\%$ and these are real condition that is not achieving the function properly. Early Deterioration of Military-Facilities bring about waste of national defense cost, environmental pollution and so on. These are not very desirable for nations, societies and environment. Therefore, this study presented maintenance improvement of the Military Facilities for of a long life-cycle of Facilities

• Journal of Digital Convergence
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• v.15 no.9
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• pp.211-221
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• 2017

The semiconductor industry develops and maintains software embedded in computer-controlled tools and facilities, to process and manufacture high-tech products. Upgrading embedded softwares for semiconductor processing robots and machinery is one of the basic activities that must be performed in order to maintain product quality and integrity. Maintenance and enhancement of embedded software consume a major portion of the total life cycle cost of a system. However, the area has been given little attention in the literature. 502 maintenance and enhancement cases, related to embedded softwares in wafer processing machines, were selected at random for analysis. Practical implications are also discussed.