• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.237-246
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• 1999

An important problem in process adjustment using feedback is how often to sample the process and when to apply an adjustment. Schemes designed to minimize the overall cost. The cost taken the frequency with which they require observations to be made, and the resulting overall length of time between adjustment. In this article, the process adjustment which is based on the adaptive EWMA forecasts are derived. An example is presented to improve confirm standard varation through the analysis of a data series.

• Journal of Korean Society for Quality Management
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• v.44 no.4
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• pp.869-881
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• 2016

Purpose: The objective of this study is to verify the economic validation of quality management integrated train freight car by analyzing economic evaluation indicators such as benefit and cost, net present value, and inter rate of return. Methods: First, we itemize benefit and cost field by reviewing literatures; Benefit consists of 1)Safety, 2)Operation, and 3)Maintenance; Cost consists of 1)Set-up fee, 2)Wireless internet fee, and 3)Cloud storage using fee. Second, based on these estimated values, we conduct an economic evaluation analysis. Among them, benefit and cost, net present value, and internal rate of return are selected. Results: As a result, all estimated values are highly over criterion of economic validity($$B/C{\geq}_-1$$, $$NPV{\geq}_-0$$, $$IRR{\geq}_-R$$); 1)benefit over cost ratio is 28.22, 2)Net present value is 8,121.66million KRW, and 3)Internal rate of return value is 2272%. Conclusion: The findings of this study will help making a decision when train industry adopts IoT technology for improving the effectiveness.

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.104-111
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• 2023

Rolling stock maintenance, which focuses on preventive maintenance, is typically implemented considering the potential harm that may be inflicted to passengers in the event of failure. The cost of preventive maintenance throughout the life cycle of a rolling stock is 60%-75% of the initial purchase cost. Therefore, ensuring stability and reducing maintenance costs are essential in terms of economy. In particular, private railroad operators must reduce government support budget by effectively utilizing railroad resources and reducing maintenance costs. Accordingly, this study analyzes the reliability characteristics of components using field data. Moreover, it resolves the problem of determining an economical replacement interval considering the timing of scrapping railroad vehicles. The procedure for determining the optimal replacement interval involves five steps. According to the decision model, the optimal replacement interval for the onboard signal device components of the "A" line train is calculated using field data, such as failure data, preventive maintenance cost, and failure maintenance cost. The field data analysis indicates that the mileage meter is 9 years, which is less than the designed durability of 15 years. Furthermore, a life cycle in which the phase signal has few failures is found to be the same as the actual durability of 15 years.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.2
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• pp.21-31
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• 2015

The world air transport industry has grown steadily with quantitative expansion. The volume of air transport in the world is skyrocketing with the open-sky trend. Air passengers from or to South Korea has shown 5% of annual growth for the last couple of decades which caused South Korea now ranking in 18th in the World for air transport market size. Quantitative expansion of Air transport affects in policy making of air transport operators, such as airports, airlines or authorities, directly and indirectly. Especially, Aviation Safety field should be supported by policy regime with the growth of air transport volume, assured resources for continuous monitoring is standing out as a vital factor. This study is to estimate social costs caused by aviation accidents and investment costs for aviation safety by airports, airlines and authorities as operators. Estimated investment costs for aviation safety verified by comparing and analysing them. Precedent studies were reviewed to refer research methodology to calculate aviation accident costs and safety costs of operators. Safety costs of operators was calculated with literature researches and interview surveys among professionals of each operators in rational range.

• International Journal of Concrete Structures and Materials
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• v.3 no.2
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• pp.103-110
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• 2009

Concrete carbonation is a cause of problems in concrete structures, so it needs to be estimated. And concrete cover is designed to protect structures from this damaging. Usually the cover thickness is considered based on the limit states design codes in which the important target is the reliability safety index. However, it is not clear that whether the safety index determined is optimal or not with respect to the cost. The codes are mainly proceeded quantitatively (i.e. making a safe structure) while the economic aspects are only considered qualitatively. So the reliability-based design considering life cycle cost (LCC) is called for, and here the focus is on the advanced analysis solution to optimize the reliability safety regarding LCC.

• KIEAE Journal
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• v.13 no.1
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• pp.159-165
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• 2013

Recently buildings are being constructed on the downtown area. In most building construction sites on the downtown area, the need for adequate material inventories are critical in order to avoid project delays and cost increases due to inappropriate deliveries of key materials. However immoderate material inventories cause increasing inventory cost. Therefore, we need a proper management material inventories. This research re-establishes the existing safety stock and analyzes relationship between safety stock and service level. It suggests an economical re-order point based on safety stock considering service level, various demand and delivery time.

• Journal of the Korean Professional Engineers Association
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• v.34 no.5
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• pp.77-81
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• 2001

The industrial accident in subway of late is increasingly coming to the front as a serious problem of society because a scale of industrial accident is a large size, and powerfulness, while the percent of accident is decreasing as a result of industrial facilities with the largeness of equipment, automation, and high horse-powering. In this paper, a study on the estimation of accident loss prevention cost and risk analysis in subway construction is proposed as an alternative to the techniques currently used in the general construction projects safety. Then the concept of risk evaluation using a risk assessment model is presented to drive value of risk and numerical example for risk analysis. A means for this does grasp the importance of educational factor by way of analyzing the causes of accident through statistical data of labor department, emphasizing the necessity and the importance of safety education, being helpful to act safety by decreasing insecure activity which ranks the majority of accident causes with putting the education program, form, method into practice that are suitable for a place of business.

• Journal of the Korea Institute of Building Construction
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• v.15 no.3
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• pp.339-349
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• 2015

A large-scale research project to develop a robot-based automated building construction system for steel structures was successfully conducted in South Korea. This paper discusses the results of the real-scale test and the key lessons gained from the testing process. The system was assessed in terms of system productivity, construction cost, quality control, and safety improvements. While the productivity of the automated system showed an improvement of about 9.5%, the construction cost was about six times higher than that of the conventional method. The field test also indicated that the automated system requires more on-site quality control measures. However, because the system can eliminate the causes of various safety accidents, safety levels might be expected to be improved significantly. It is expected that this paper will provide knowledge and insight for developing new systems, and the results of the real-scale test might be useful for other researchers and similar research projects in the future.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.1-4
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• 2002

A automatic production system was developed for high productivity and safety. The semi-progressive die was unfavorable for more productivity, safety, material extravagance and incongruent high-speed production. Developed progressive die is suitable for the high production and guarantee triple production by acceptance of three array type for automobile adjust plate. We adopt Pro-$Engineer{\circledr}$ for three dimensional computer aided design suitable for the disassembly and assembly evaluation. The conclusion of this study is as follow. First, press die parts solid modeling system is built by using Pro-$Engineer{\circledr}$ through this research and verified allowable tolerance and possibility of assembly and disassembly of parts. Therefore we can reduce die manufacturing time and cost. Second, We produce 1000 units pet hot coil 1ton by traditional method, but we can acomplish material saving effect about 12% as 120 units in case of new progressive die. Fourth, we acomplished manufacturing cost curtailment effect more than 20% in comparison with traditional method.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.143-155
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• 2016

Recently, a massive loss of life and property is occurring in Korea due to traffic accidents, with the rapid increase in cars. For improvement of traffic safety, the Korea Transportation Safety Authority intensively analyzes accident data in local governments with low traffic safety index, performs a field investigation to extract problems and offers local governments improvements for problems, by conducting the 'Special Survey of Actual Conditions of Traffic Safety' each year, starting 2008. But local governments cannot strongly push forward the improvement projects due to the limited budget and the uncertainty of the improvement plan effects. Therefore, this study suggested a model which applied the Utility concept to the AHP theory, in order to efficiently decide a priority of the improvement plans in accident black spots in consideration of the limited budget of local governments. The number of accidents in each spot for improvement and accident severity, traffic volume, pedestrian volume, the improvement project cost and the accident reduction effect were chosen as evaluation factors for deciding a priority, and data about the improvement plan costs and the accident reduction effects, traffic accidents and traffic volume in the spots to undergo the special research on the real condition of traffic accident in the past were collected from the existing studies. Then, regression analysis was carried out and the Utility Curve of each evaluation factor was computed. Based on the AHP analysis findings, this study devised a priority decision method which calculated the weight and the utility function of each evaluation factor and compared the total utility values. The AHP analysis findings showed that among the evaluation factors, accident severity had the biggest importance and it was followed by the improvement plan cost, the number of accidents, the improvement effect, traffic volume and pedestrian volume. The calculated utility function shows a rise in utility, as the variables of the 5 evaluation factors; the number of accidents, accident severity, the improvement plan effect, traffic volume and pedestrian volume increase and a fall in utility, as the variables of the improvement plan cost increase, since the improvement plan cost is included in the budget spent by a local government.