• Communications for Statistical Applications and Methods
• /
• 제17권6호
• /
• pp.755-765
• /
• 2010

혼합분포의 분류문제에서 비용함수를 고려한 분류점은 최소 기대비용이라는 측면에서 최적이다. 비용에 관한 어떠한 정보가 주어지지 않은 경우에 ROC곡선을 이용하여 분류정확도 측도인 전체정확도와 진실율이 최대일 때의 분류점에 대응하는 기대비용에서의 비용비율을제안하고, 최소 기대비용의 비용비율과의 관계를 설명한다. 그리고 비용곡선을 이용하여 분류정확도 측도들에 기반하는 최소 기대비용에서의 비용비율을 제안하였고 이 비용비율은 대표적인 두 종류의 분류정확도가 최대일 때의 기대비용에 대한 비용비율들 사이에 존재하며, 최소 기대비용에서의 비용비율에 수렴하는 것을 발견하였다. 본 연구는 기대비용과 정규화된 기대비용을 최소화할 때의 비용비율과 분류정확도가 최대일 때의 비용비율들의 관계를 토론한다.

• 한국경영과학회지
• /
• 제15권1호
• /
• pp.63-72
• /
• 1990

This problem in this paper concerns the determination of safety stock for multi-echelon invenetory system. In this model the criterion is to minimize system safety stock subject to a service level constraint and expected annual total cost. Then, safety stock is determined by minimizing expected annual total cost and satisfying given service level. This expected annual total cost is obtained by expected total inventory holding cost plus the expected total stockout cost. Numerical example is given in a three-echelon inventory system. The results obtained by the use of the Hill Algorithm.

• 한국농공학회논문집
• /
• 제49권6호
• /
• pp.93-101
• /
• 2007

In general, geotechnical properties have many uncertain aspects, thus probabilistic analysis have been used to consider these aspects. It is, however, quite difficult to select an appropriate target probability for a certain structure or construction process. In this study, minimum expected cost design method based on probabilistic analysis is suggested for design of vertical drains generally used to accelerate consolidation in soft clayey soils. A sensitivity analysis is performed to select the most important uncertain parameters for the design of vertical drains. Monte Carlo simulation is used in sensitivity analysis and probabilistic analysis. Total expected cost, defined as the sum of initial cost and expected additive cost, varies widely with variation of input parameters used in design of vertical drain systems. And probability of failure to get the minimum total expected cost varies under the different design conditions. A minimum value of total expected cost is suggested as a design value in this study. The proposed design concept is applicable to unit construction process because this approach is to consider the uncertainties using probabilistic analysis and uncertainties of geotechnical properties.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제12권2호
• /
• pp.57-66
• /
• 2012

In this paper, we consider the periodic preventive maintenance model for a repairable system following the expiration of replacement-repair warranty. Under this preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• International Journal of Reliability and Applications
• /
• 제12권2호
• /
• pp.117-122
• /
• 2011

In this paper, we suggest the optimal replacement policy following the expiration of repair warranty when the cost of minimal repair depends on the age of system. To do so, we first explain the replacement model under repair warranty. And then the optimal replacement policy following the expiration of repair warranty is discussed from the user's point of view. The criterion used to determine the optimality of the replacement model is the expected cost rate per unit time, which is obtained from the expected cycle length and the expected total cost for our replacement model. The numerical examples are given for illustrative purpose.

• 한국의상디자인학회지
• /
• 제17권3호
• /
• pp.169-182
• /
• 2015

The purpose of this study was to analyze narcissism, clothing expected benefits, and make-up expected benefits of female college students and investigate the relationships of them. To achieve the purposes, a questionnaire was conducted to 322 from September 21 to October 30, 2014. The final data was analyzed with spss 18.0 program. The results were follows. First, It was found that narcissism were classified 4 factors of success-oriented narcissism, others-defensive narcissism, recognition-oriented narcissism, appearance-fascinated narcissism. Second, It was found that clothing expected benefits were classified 6 factors and make-up expected benefits were classified 4 factors. Third, there were significant differences of narcissism by major, clothing purchase cost and cosmetic purchase cost. Forth, there were significant differences of clothing expected benefits and make-up expected benefits by major, clothing purchase cost and cosmetic purchase cost. Fifth, there were significant relations of narcissism, clothing expected benefits, and make-up expected benefits of female college students. Thus, it was found that narcissism were related to clothing expected benefits and make-up expected benefits.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제12권4호
• /
• pp.255-263
• /
• 2012

This paper considers the cost analysis from the manufacturer's point of view for renewing replacement and non-renewing repair warranty(RRNRW) of a repairable system. To do so, we consider the renewing replacement and non-renewing repair warranty, which is proposed by Jung(2011). To analysis the expected warranty cost from the manufacturer's perspective for renewing replacement and non-renewing warranty, we obtain the expected total warranty cost and the expected warranty length which are very important information for the manufacturer. Finally, the numerical examples are presented for illustrative purpose.

• Journal of the Korean Data and Information Science Society
• /
• 제14권4호
• /
• pp.889-901
• /
• 2003

In this paper, we consider the optimal replacement policies following the expiration of the combination warranty. The combination warranty can be divided into the renewing combination warranty and the non-renewing combination warranty. The criterion used to determine the optimal replacement period is the overall value function based on the expected cost and the expected downtime. Thus, we obtain the expected cost rate per unit time and the expected downtime per unit time for our model. And then the overall value function suggested by Jiagn and Ji(2002) is applied to obtain the optimal replacement period. The numerical examples are presented for illustrative purpose.

• Journal of the Korean Data and Information Science Society
• /
• 제17권3호
• /
• pp.743-752
• /
• 2006

This paper considers a Bayesian approach to replacement policy model with minimal repair. We use the criterion based on the expected cost and the expected downtime to determine the optimal replacement period. To do so, we obtain the expected cost rate per unit time and the expected downtime per unit time, respectively. When the failure time is Weibull distribution with uncertain parameters, a Bayesian approach is established to formally express and update the uncertain parameters for determining an optimal maintenance policy. Especially, the overall value function suggested by Jiagn and Ji(2002) is applied to obtain the optimal replacement period. The numerical examples are presented for illustrative purpose.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제6권3호
• /
• pp.195-203
• /
• 2006

This paper deals with cost analysis model in periodic maintenance policy. The repair policy with minimal repair is considered as follow : as the occurrence of failure between minimal repair and periodic interval time, unit is replaced by a new unit before the periodic maintenance time comes. Then total expected cost per unit time is calculated according to time delta t in a view of customer's. The total expected costs are included repair and usage cost : operating, fixed, minimal repair, periodic maintenance and new unit expected cost. Numerical example is shown in which failure time of item has Normal distribution.