• 산업경영시스템학회지
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• 제8권11호
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• pp.35-43
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• 1985

In this paper we will concentrate on the Quality Control Policy which should be enforced as a part of the Total Quality Control considers the global concepts, the establishment Procedures, and the evolution and operation of Quality control policy to achieve effectively it. For enforcement of the Qualify control policy shall be focused for considerations : (1) suggestion of the optimum control policy (2) suggestion of a comprehensive plan and promoting method quality control (3) suggestion of matters that need special consideration at the time of decision of a comprehensive management of control policy thereof. (4) A comprehensive Proposal (5) suggestion of a plan for progress of the Quality control system and the supplementary plan In the future, accordingly, establishment d its own policy control level is desirably more reasonable, and the Total Quality Control System that employes the control efficiency of periodical and systematic and rationalization and radical reform of the enterprise management problem as the restrictive conditions must be applied for quality control system.

• 한국경영과학회지
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• 제8권2호
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• pp.9-25
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• 1983

A new approach to cross impact analysis using probabilistic system dynamics(PSD) is presented in this article. The previous models using PSD consist of system dynamics models as a basis which are interacting with cross impact analysis (CIA) sectors. In this model, the policy impact analysis part is separated from the CIA sectors and is constituted an independent subsectors of the model. The policy subsector is designed to separate the policy impact and provide feedback both to the system dynamics base model and cross impact analysis sectors. The new technique is applied to the forecasting, assessment and policy formulation of air pollution in Seoul metropolitan area in 2,000. The results show that the new tool consider policy effects more effectively than the previous PSD models.

• 보건행정학회지
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• 제11권4호
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• pp.129-151
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• 2001

This study was conducted to describe trends of health services research (HSR) in Korea since 1968 and analyse the relevance of HSR to changes in health policy. Research methods are as follows: firstly, HSR articles were selected from 4 HSR related journals implicitly. Secondly, classification system of HSR was developed and then applied to previously selected papers in order to describe research trends. Finally, the frequency rankings of articles in research areas were compared with rankings in order of the importance of research area rated by experts. As a resesult, HSR articles have increased with time and three main research areas are health programme, health care financing, and health care organization/management. And many articles have been related to the efficiency and quality of health care since 1990. It seems HSR articles had little relevance to changes in health policy and policy environment. Especially, the recently disputed policy topic, namely the separation of prescription from disposing, has not received little attention since 1990. These findings suggest there is an urgent need for the reflection on HSR direction in Korea.

• 디지털융복합연구
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• 제11권11호
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• pp.435-441
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• 2013

본 논문은 빅데이터 서비스를 위한 커버로스 보안 인증 방안과 정책에 대해 살펴보았다. 빅데이터 서비스 환경에서 하둡 기반의 보안기술에 대한 문제점에 대해 분석하였다. 또한 커버로스 보안 인증체계의 적용 문제를 고려할 때 미국의 상용 분야에서 발생하고 있는 주요 내용을 중심으로 적용 정책을 분석하였다. 커버로스 정책 적용과 관련하여, 미국은 크로스플랫폼 상호운용성 지원, 자동화된 커버로스 설정, 통합 이슈, OTP인증, 싱글사인온, ID 등 다양한 적용에 대한 연구가 이루어지고 있다.

• Journal of applied mathematics & informatics
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• 제8권1호
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• pp.199-212
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• 2001

We consider a k-out-of-n system with repair under T-policy. Life time of each component is exponentially distributed with parameter $\lambda$. Server is called to the system after the elapse of T time units since his departure after completion of repair of all failed units in the previous cycle or until accumulation of n-k failed units, whichever occurs first. Service time is assumed to be exponential with rate ${\mu}$. T is also exponentially distributed with parameter ${\alpha}$. System state probabilities in finite time and long run are derived for (i) cold (ii) warm (iii) hot systems. Several characteristics of these systems are obtained. A control problem is also investigated and numerical illustrations are provided. It is proved that the expected profit to the system is concave in ${\alpha}$ and hence global maximum exists.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• 산업경영시스템학회지
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• 제33권2호
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• pp.97-104
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• 2010

Using the known result of the expected busy period for the triadic Min (N, T, D) operating policy applied to a controllable M/G/1 queueing model, its upper and lower bounds are derived to approximate its corresponding actual value. Both bounds are represented in terms of the expected busy periods for the dyadic Min (N, T), Min (N, D) and Min (T, D) and simple N, T and D operating policies. All three input variables N, T and D are equally contributed to construct such bounds for better approximations.

• 한국신뢰성학회지:신뢰성응용연구
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• 제1권1호
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• pp.35-46
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• 2001

Replacement policy of a degradation system is investigated by incorporating the loss function. Loss function is defined by the deviation of the value of quality characteristic from its target value, which determines the loss cost. Cost function is comprised of the inspection cost, replacement cost and loss cost. Two cost minimization problems are formulated : 1)determination of an optimal inspection period given the state for the replacement and 2)determination of an optimal state for replacement under fixed inspection period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function and inspection cost, respectively As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspection cost is observed to be insensitive. This study can be applied to the replacement policy of a degradation system which has to produce the quality critical product.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권3호
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• pp.188-196
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• 2017

Purpose: The purpose of this research is to determine optimal replacement age using non-informative prior information and Bayesian method. Methods: We propose a novel approach using Bayesian method to determine the optimal replacement age in block replacement policy by defining the prior probability with data on failure time and repair time. The Marcov Chain Monte Carlo simulation is used to investigate the asymptotic distribution of posterior parameters. Results: An optimal replacement age of block replacement policy is determined which minimizes cost and nonoperating time when no information on prior distribution of parameters is given. Conclusion: We find the posterior distribution of parameters when lack of information on prior distribution, so that the optimal replacement age which minimizes the total cost and maximizes the total values is determined.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권4호
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• pp.316-324
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• 2017

Purpose: The purpose of this study is to determine the replacement cycle applied age replacement policy by reliability analysis based on railway vehicle contactor's failure history data. Method: We performed reliability analysis based on railway vehicle contactor's failure history data. We found a suitable distribution by goodness of fit test and predicted the reliability through estimation of scale & shape parameter. Considering cost information we determined the replacement cycle that minimize the opportunity cost. Result: Suitable distribution was the Weibull and scale parameter & shape parameter are estimated by reliability analysis. The replacement cycle was predicted and MTTF, $B_6$ percentile life were suggested additionally. Conclusion: We confirmed that failure rate type of railway vehicle contactor is degradation model having a time dependent characteristic and examined the replacement cycle in our country's operating environment. We expect that this study result contribute to railway operation agency for maintenance policy decision.