• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.171-177
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• 2007

In this paper, an evaluation method of fracture toughness on interface cracks was investigated in friction welded dissimilar materials with interfacial edge cracks. To establish a reasonable strength evaluation method and fracture criterion, it is necessary to analyze stress intensity factor under the load and residual stress condition on friction welded interface between dissimilar materials. The friction welded specimens with an edged crack were prepared for analysis of stress intensity by using the boundary element method (BEM) and the fracture toughness. A quantitative fracture criterion for friction welded STS 304/SM 45C with interface crack is suggested by using stress intensity factor, F and the results of fracture toughness experiment.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.149-155
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• 2005

We have proposed an objective evaluation method using ESNR as the measure of approximation by the visual model, which coincides with MOS, a subjective evaluation method. For two-value images, we have used five kinds of modulation methods: 1) ordered dither, 2) least mean error, 3) pulse density low division, 4) simple two-value, and 5) random dither methods. The purpose of this paper is to investigate the validity of ESNR, by comparing the proposed method together with the existing representative methods such as PSNR and WSNR, with the subjective method MOS. The results of a series of experiments show that the ranking by MOS coincides with ESNR, though does not coincides with PSNR and WSNR.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.1
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• pp.1-8
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• 2003

There are many statistical evaluation methods, A more technical Perspective is needed in estimating the effect of the Manufacturing Process for improving the Productivity, Process network analysis is a technique which has the potentiality for a wire use to improve the manufacturing process which other techniques can't be used to analyze effectively. The concept of six sigma plan was developed and pursued by Motorola to improve the process control. The goals of six sigma plan are established on the foundation of customer satisfaction such as Quality, Cost Delivery and Service This paper presents how to improve the manufacturing process by statistical process control for the evaluation of six sigma level.

• Proceedings of the KWS Conference
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• 1995.04a
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• pp.118-122
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• 1995

The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic machinaries as mechanical industry is developed rapidly. The machining precision is asked for manufacturing the valve spools. They could be unstable in the quality by the conventional arc welding and they have a lot of technical problems in manufacturing because their shapes are generally small. By the Precision casting process such as lost wax process, the production cost will be increased. But by the friction welding technique, they will be able to be made without such problems. Furthermore, there is a few study on friction welding of such hydraulic valve spool steels and in-process real-time weld quality evaluation technique by acoustic emission. So that, the final purpose of this study is 1) the development of design and manufacturing technique of hydraulic or pneumatic valve spool by optimizing of friction welding, and 2) the development of in-process real-time weld quality evaluation technique by acoustic emission.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.149-151
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• 1997

Korea Water Resources Corporation (KOWACO) has used hard wired sequential control system for dams and SCADA / DCS for water supply offices. The control system, which consists of automatic control, communication and computer science, has to look for the security of operation and the quality of generated power and treated water. In this paper, we would like to propose the systematic evaluation of technical proposals such as purpose, method/procedure, evaluation criteria and report preparation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.3
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• pp.124-135
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• 2000

This paper presents reasonable evaluation technique to determine system configuration of underground distribution system. To set up reasonable evaluation for a certain object region, it is necessary for methodology to access accurately factors such as economics, reliability, customer interruption cost, implementation and flexibility about proposed various configuration of underground distribution system. But it is difficult to evaluate factors as above-mentioned since there is no criterion to assess them in our country. Accordingly, having completed the technical and economical analysis and customer interruption cost of various types of system, this paper presents the most reasonable results to get the optimal configuration of underground distribution system. Also, this paper presents possible methodology which can be applied other areas having a different load characteristics by application actually making a selection Myungdong as sample area.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.264-267
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• 2004

Wall thinning of carbon steel pipe components due to Flow-Accelerated Corrosion (FAC) is one of the most serious threats to the integrity of steam cycle piping systems in Nuclear Power Plants (NPP). Since the mid-1990s, secondary side piping systems in Korean NPPs have experienced wall thinning, leakages and ruptures caused by FAC. Korea Electric power Research Institute (KEPRI) and Korea Hydro & Nuclear Power Co., LTD. (KHNP) have conducted a study to develop the methodology for systematic pipe management and established the Korean Thinned Pipe Management Program (TPMP). To effectively maintain the integrity of piping system, FAC engineer should understand the criterions of the structural integrity evaluation and the safety margin assessment for the thinned pipe component. This paper describes the technical items of TPMP, and shows the example of the integrity evaluation and safety margin assessment for three thinned pipe component of a NPP.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.519-524
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• 2003

Systems engineering test and evaluation technology development program for (Korea) Express Tilting Train(TTX) system in progress is a national large system development program that is not only a large-size and complex but also multi-disciplinary in nature. For the TTX test and evaluation technology development, verification requirements that could verify system function and performance, should be derived from system specification. Hereafter, this could be listed as items of test. System engineering process establish traceability between items of test and system requirements. These tasks could be accomplished by the schema. Using the Core, a system engineering tool, TTX program could be database and similar other system could be developed effectively and efficiency

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.310-312
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• 2003

This paper discusses a GIS based decision support system that provides functions of prospect screening and evaluation in both technical aspects (Volume, structure, trap, reservoir and charge, etc.) and economic aspects (Net present value, Profit / investment Ratio, etc.). The decision support system has been tested in a virtual offshore exploration prospect to facilitate and improve the decision making process. The study represents a test bed for decision makers at all levels to establish prospect screening and evaluation guidelines that may be applicable to other related prospect investment issues.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.9-19
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• 2011

Most real world design evaluation and risk-based decision support combine quantitative and qualitative (linguistic) variables. Decision making based on conventional mathematics that combines qualitative and quantitative concepts always exhibit difficulty in modelling actual problems. The successful selection process for choosing a design/procurement proposal is based on a high degree of technical integrity, safety levels and low costs in construction, corrective measures, maintenance, operation, inspection and preventive measures. In this paper, a design decision support framework using a composite structure methodology grounded in approximate reasoning approach and evidential reasoning method is suggested for design evaluation of machinery space of a ship engine room at the initial stages. An illustrative example is used to demonstrate the application of the proposed framework.