• Journal of the Korean Society of Safety
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• v.17 no.3
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• pp.61-65
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• 2002

A study on the characteristics of electric shock in fresh water due to the leakage of submerged electric facility is conducted by using a reduced scale model at a scale of 1:10 in laboratory. Electric potential as a function of distance from leakage source, type of the leakage source, magnitude of the source voltage, submerged depth and diameter of a copper rod electrode is measured. On the basis of safety standard, separation for guarantee of safety is determined by the measured potential. Also supposing that body resistance is 500［$\Omega$］, the human reaction was estimated by calculating body current for some shock duration. Thus, in this paper, the hazard of the electric shock is assessed by introducing representative safety factors, body voltage and body current due to leakage source.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.82-84
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• 2000

통화시간에 대한 할인율 적용 혹은 짧은 통화에 요금을 부과하지 않은 정책 등 마케팅활동의 효과분석 및 마케팅전략을 수립하는데 있어서 통화시간 분석은 매우 중요하다. 기존연구들은 설명변수의 도입이 편리한 비례위험함수(proportional hazard function) 을 활용해 왔다. 그러나 이 방법은 추정이 용이하지 않다는 약점을 갖고 있다. 특히 통화행태를 설명하기위해 다양한 설명변수를 도입하는 경우, 기존에 상용화된 통계패키지로 추정하는데 한계점을 갖고 있다. 본 연구에서는 추정의 용이성에 초점을 맞추어, 실무자들이 손쉽게 통화시간에 대한 마케팅 노력의 효과를 분석할 수 있는 분석방법론을 제시하고, 제시된 분석방법을 이용하여 판촉활동 (요금할인)이 통화대기시간과 통화시간에 미치는 영향을 실증분석 하고 있다.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.289-303
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• 1992

Investigation of the environmental impact of widespread pesticide use has revealed a virtue/vice relationship. Although many pesticides perform their function and disappear without harm to the environment, others persist beyond their useful purpose and cause direct of indirect hazard to man, domestic animals and wildlife. Concurrently, many pests have rapidly adjusted to chemical control practices through changes in behavior that avoid exposure to pesticides of throuth genetic selection for populations resistant to the toxicants. The prospect of losing control over insect herbivores and desease vectors and returning to the days of global hunger and disease is unthinkable. Fortunately, from basic studies of insect and plant biology many opportunities for the development of safe, selective and environmentally pacific strategies for insect pest management are being realized.

• Journal of the Korean Society for Railway
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• v.8 no.5
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• pp.470-476
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• 2005

RCM developed by American air industry in early 1960, its process is most realistic for some physical assets and it permits the system to maintain given function status through decision of demand about optimum maintenance. Therefore, many industries have selected RCM technique and have carried out RCM in order to solve many problems concerning maintenance management as improvement of reliability and availability of facilities, removal of hazard element about break down and retrenchment of maintenance cost. Through the execution of RCM, we can solve actual problems. And finally we will be able to develop more and more maintenance activities with RCM notion. In this study, we will consider the application of KTX-RCM which is set up with basic theory of RCM and constructed to improve vehicle safety, availability and regularity of KTX, linking with CMMS(Computerized Maintenance Management System).

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.135-142
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• 2007

The service running of driverless rail vehicle has been required by various social and commercial issue. Currently, the new domestic line between Bu-san and Gim-hae is plan to be provided the LRV(Light Rail Vehicle) with driverless operation firstly in domestic service. These driverless vehicle have some major properties to make it lower the operating and maintenance cost, however on the other side, it unavoidably raise some potential hazard to make it lower the passenger safety because it is hard to take care immediately in emergency state during vehicle running. Therefore it is highly requested that we should consider various conditions at design stage to manufacture and operate the safest vehicle. Therefore, in this paper, we will survey the design concept of vehicle interior facilities based on the previous experience, (1) The difference of interior facilities between normal and driverless vehicle, (2) design and operational concept of passenger side door function to find out best application for domestic line driverless vehicle.

• Journal of Dairy Science and Biotechnology
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• v.31 no.2
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• pp.195-200
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• 2013

The ripening of cheese allows for the development of characteristic taste and flavour, nutritional substances, bio-active components and texture, helping to improve quality. Many different microbiological, biochemical and nutritional changes occur during the process depending on the quality of raw milk, added cultures and enzymes, as well as specific processing and ripening conditions. During the ripening lactose is hydrolyzed to lactic, propionic and acetic acid, helping to reduce potential effects of the problem of lactose intolerance. Fat is hydrolyzed to butyric, propionic and conjugated linoleic acid, which function as bio-active substances. Protein is hydrolyzed to different peptides and amino acids which all show various bio-activities. However, errors of cheese ripening can happen and affect the quality of the product. To guarantee good quality cheese the process needs to be managed carefully with the right microbes used and ensuring cleanliness of processing facilities, staff, ventilation and hazard analysis and critical control points (HACCP). Research into and controlling of ripening technology is crucial for producing high quality cheeses.

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.60-70
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• 1997

Since, human error is a major factor contributing to disaster during start-up of operation in Boiler plant. it is necessary to develop an automation system which prevent mode of operation that are known to be dangerous and to bring a loss of energy. The aim of this study is to suggest a model for the computer-aided synthesis of operation sequence as a part of automation system for start-up operation. Synthesis is accomplished by the formation of a hierarchical network of goals which decide sequence of operations. Hierarchical Network is formed by using method which upper goals ( i.e. upper operation al situation) are classified by the function of themselves into lower goals (i.e. lower operational situation). Knowledge for deciding operation sequence is generated by putting In order the knowledge of hazard operation and energy management.

• Journal of the Korean Statistical Society
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• v.26 no.4
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• pp.429-443
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• 1997

We consider the problem of obtaining several types of simultaneous confidence bands for the survival curve under the additive risk model. The derivation uses the weak convergence of normalized cumulative hazard estimator to a mean zero Gaussian process whose distribution can be easily approxomated through simulation. The bands are illustrated by applying them from two well-known clinicla studies. Finally, simulation studies are carried outo to compare the performance of the proposed bands for the survival function under the additive risk model.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.73-78
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• 2005

This paper considers a preventive maintenance policy following the expiration of renewing warranty, Most preventive maintenance models assume that each PM costs a fixed predetermined amount regardless of the effectiveness of each PM. However, it seems more reasonable to assume that the PM cost depends on the degree of effectiveness of the PM activity. In this paper we consider a periodic preventive maintenance policy following the expiration of renewing warranty when the PM cost is an increasing function of the PM effect. The optimal number and period for the periodic PM policy with effect dependent cost that minimize the expected cost rate per unit time over an infinite time span are obtained.

• Journal of Korean Society for Quality Management
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• v.19 no.2
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• pp.117-124
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• 1991

In this paper, it is assumed that a system is composed of an essential unit and a nonessential unit. During the running of the system, an essential unit is replaced at periodic replacement time T or at nth failure of essential unit whichever occurs first. Nonessential unit is replaced at its failure and at the replacement of essential unit. This paper derive optimal replacement period which minmises the total expected cost for replacement. The unimodality of totoal maintenance cost function is proved under the assumption that hazard rate of each component is continuous and monotone increasing failure rate(IFR). Based on this condition, it is shown that the optimal replacement period is finite and unique.