• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.240-246
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• 2022

This study was conducted to develop a domestic product for a flow control valve for a hydrogen refueling station, and a domestic prototype was manufactured and the durability performance evaluation was conducted through comparison with an imported products. The stress generated by the internal pressure was checked and safety was confirmed using a commercial structural analysis program, ABAQUS, in accordance with the withstand pressure test standards. In addition, after identifying the weak areas the fatigue life was predicted through a commercial software, fe-safe. This fatigue analysis showed that the hydrogen gas repeated test criteria were satisfied.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.361-366
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• 2002

The deterioration of concrete structure due to corrosion of the reinforcement has created big financial losses on the overall industries. The volume expansion of the corrosion products causes internal pressure to concrete wall around reinforcing bar. If the maximum principal stress induced by internal pressure exceeds the tensile strength of the concrete at any point of time, a crack forms at any point of material. Therefore, in terms of life assessment of concrete structure, it is very important to predict the amount of corrosion products which induces initial concrete cracking. With this objective, this paper proposes the critical amount of corrosion products at interface between reinforcement and concrete using finite element analysis. If an actual survey of corrosion rates could be made, the model might supply information for condition assessment of existing concrete structure. As the mechanical properties of corrosion product and instantaneous geometry of corroded steel are considered in the analysis, the value obtained will be more realistic.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.107-113
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• 2001

Consumer Product compounds are used in homes and disposed in wastewater where they typically receive waste treatment. After treatment, sludge and effluent are released to the environment resulting in the potential exposure of terrestrial and aquatic organisms to these compounds. To ensure the environmental safety of these compounds, the environmental risk posed by chemicals released into the environment must be assessed. A reasonable, consistent and cost-effective method to conduct environmental risk assessments and to prioritize testing of these chemicals is needed which addresses risk to organisms residing in the terrestrial and aquatic compartments of the environment. This paper provides a fundamental understanding of the technical basis of environmental risk assessment using the major surfactant(i.e., LAS) used in the laundry detergent industry worldwide as a case study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.324-327
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• 2001

This paper shows an example of the Design Review and Common-Cause Failure (CCF) Modeling of mechanical Parts. Reliability should be continuously monitored during the entire period of design. Design Review is the procedure to improve the reliability for the product. We proposed the reliability assessment and design review method. CCF Model is the general dependent model considering the failure mode effects several component simultaneously. This study considers the computation of the network with dependent components. It is important that CCF model is applied for mechanical pars.

• Ocean Systems Engineering
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• v.8 no.2
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• pp.119-166
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• 2018

The assessment of the potential for the design of marine renewable energy systems is reviewed and the current situation for marine renewable energy is promising. The most studied forms of marine renewable energy are ocean wind energy, ocean wave energy and tidal energy. Wind turbine generators include mostly horizontal axis type and vertical axis type. But also more exotic ideas such as a kite design. Wave energy devices consist of designs converting wave oscillations in electric power via a power take off equipment. Such equipment can take multiple forms to be more efficient. Nevertheless, the technology alone cannot be the only step towards marine renewable energy. Many other steps must be overcome: policy, environment, manpower as well as consumption habits. After reviewing the current conditions of marine renewable energy development, the authors analyzed the key factors for developing a strong marine renewable energy industry and pointed out the huge potential of marine renewable energy.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.193-198
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• 2005

According to the ISO 14040(1997), Life Cycle Assessment is not the tool only focusing on the emissions from the manufacturing processes of a product, but the tool also expressing environmental adverse impact quantitatively through products entire life cycle (i.e. raw material acquisition, manufacturing, transportation, use, and end-of-life stage). Because the LCA for EMUs(Electrical Multiple Units), however, requires astronomical time and cost for collecting big amount of data. it is inevitable to bring in the simplified LCA methodology, In this study, we introduced standardized methodology of LCA in the world, and found appropriate S-LCA methodology for EMUs. Furthermore, we recommended how to evaluate the environmental impact of EMUs in detail and precisely, using the S-LCA.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.589-593
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• 2007

Due to sustainable development, international environmental regulations have been reinforced continuously. Especially, Kyoto protocol related to energy consumption affects to national production system seriously. Even if railroad is the most environmental- friendly transportation, it is necessary to improve its environment. Life cycle assessment (LCA) is a representative tool to evaluate the environment impacts of a product. In the EU's railroad companies, the recycling efficiency and the waste emissions of rolling stocks have improved considering their environment impacts with LCA from a design step. Also, the LCA system of Korean electric motor units has been developed to build an environmentally sound railroad as one of national transportation core technology R&D projects. Therefore, the introduction of LCA will be required to decrease environmental impacts released from rolling stocks in the future.

• The Journal of the Korean life insurance medical association
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• v.26
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• pp.41-53
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• 2007

In the course of insurance claim administration, medical experts' opinions are called medical claim reviews. They are classified into two main categories: medical verification and counsel for claim staff. Medical verification compare between product coverage and the insured's physical condition. Medical counsel for claim staff is advice for claim staff when they have a question about medical knowledge to make a claim decision. A common example of medical verification is insurance coding of pituitary apoplexy. Some clinicians have insisted that the ICD coding of pituitary apoplexy is l63 of cerebral infarction, but the exclusion criteria of I code show that neoplasm is coded as C00 to D48. Thus, pituitary apoplexy must be coded as D33. An example of medical counsel for claim staff is interpretation of some medical conditions. It is divided into UCR(usual, customary, and reasonable) assessment, assessment of causality, and so on. Disability evaluation is another subject of medical counsel for claim staff. The final claim decision must be made by claim staff because only the claim staff have the authority of claim decision. Medical claims review is only an expert's opinion.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.29-36
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• 2005

In oder to generate various shock signals in a field study, a passenger car was driven at several speeds over road profiles that included a number of half sine shaped bumps of various heights. A triaxial SAE pad sensor was mounted on the front passenger seat to measure the acceleration signals which might produce subjective discomfort. The measured accelerations were correlated with the subjective assessments of 14 subjects. The magnitude of subjective discomfort was found to be proportional to the VDV and also the peak to peak of the frequency weighted acceleration signal.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.13 no.21
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• pp.29-41
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• 1990

An assessment of risk in industrial and urban environments is essential in the prevention of accident and in the analysis of situations which are hazardous to public health and safety. The risk imposed by a particular hazard increases with the likelihood of occurence of the event, the exposure and the possible consequence of that event. In a traditional approach, the calculation of a quantitative value of risk is usually based on an assignment of numerical values of each of the risk factors. Then the product of the values of likelihood, exposure and consequences called risk score is derived. However vagueness and imprecision in mathematical quantification of risk are equated with fuzziness rather than randomness. In this paper, a fuzzy set theoretic approach to risk analysis is proposed as an alternative to the techniques currently used in the area of systems safety. Then the concept of risk evaluation using linguistic representation of the likelihood, exposure and consequences is introduced. A risk assessment model using approximate reasoning technique based on fuzzy logic is presented to drive fuzzy values of risk and numerical example for risk analysis is also presented to illustrate the results.