• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.19 no.38
• /
• pp.77-83
• /
• 1996

The design of multi -echelon distribution system is need for appropriate inventory control strategy considering for systematic tradeoff between trunk cost in central warehouse and inventory cost in regional warehouse. This study presents a method of the efficient inventory control of multi-echelon distribution system through partial leadtime management.

• Proceedings of the Korean Society for Information Management Conference
• /
• 1995.08a
• /
• pp.41-44
• /
• 1995

Twenty six databases relevant to ‘trade’ have been searched to test for a Bradford's law of scatter. Citations in the databases adhere to the linearity of Bradford's distribution, however, they show that the concentration of citations in core databases is not as great as being expected.

• Korean Management Science Review
• /
• v.22 no.2
• /
• pp.99-107
• /
• 2005

Recently, Tang and Chanson proposed a minimum cost distribution model for replicated Web contents subject to an expiration-based consistency management. Their model is a progress in that it can consider multiple replicas via the network of servers located on the Web. The proposed greedy heuristic, however, has an undesirable feature that the solution tends to converge a local optimum at an early stage of the algorithm. in this paper, we propose an algorithm based on a simple idea of preventing the early local convergence. The new algorithm provides solutions whose cost are, on the average, 27$\%$ lower than in the previous algorithm.

• Journal of Korean Society for Quality Management
• /
• v.22 no.1
• /
• pp.162-168
• /
• 1994

In this paper we develop an unconditional method for inferences on the shape parameter of a gamma distribution. A simple numerical implementation of this unconditional method is developed; this is a computer program that takes the observed data as input and produces the confidence distribution function for the shape parameter, which in turn provides approximate observe significance levels and confidence intervals for that parameter, as output. These approximations are extremely accurate even for very small sample size and numerically simple and easy to obtain.

• Proceedings of the Safety Management and Science Conference
• /
• 2007.04a
• /
• pp.295-307
• /
• 2007

This paper introduces statistical test principles, statistical procedures and tests for exponential distribution. This paper also shows compliance test plans for success ratio and constant failure rate, and goodness-of-fit tests for Weibull distribution. Moreover, this paper presents procedures for comparision of two constant failure rates, and dependability of products containing reused parts.

• Journal of Korean Society for Quality Management
• /
• v.14 no.1
• /
• pp.39-46
• /
• 1986

This paper considers two sided tests for exponential null distribution against NBUE or NWUE alternative in life testing. The main results concern the strong consistency of two proposed statistics, one being similar to Kolmogorov - Smirnov statistic, the other similar to Cramer-Von Mises statistic. Also obtained are the asymtotic null distribution and the exact Bahadur slope of the statistic similar to Kolmogorov-Smirnov.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1993.10a
• /
• pp.24-30
• /
• 1993

When modeling a complex system we use an event tree to analyze propagation of failure. An event tree cannot represent the statistical interrelationships among parameters, but it can be represented as a statistically identical influence diagram so that parameter updating can be easily performed. After updating parameters we can calculate posterior distribution of the failure rate for each path. But exact distribution requires considerably complex numerical integration. We propose an approximation method to calculate the posterior and derive the predictive distribution of the time to next failure. Finally we introduce the system which implements our methodology.

• Journal of the Korea Safety Management & Science
• /
• v.2 no.2
• /
• pp.71-83
• /
• 2000

This paper presents accelerated life tests for Type I censoring data under probabilistic stresses. Probabilistic stress, $S_j$, is the random variable for stress influenced by test environments, test equipments, sampling devices and use conditions. The hazard rate, ,$theta_j$, is the random variable of environments and the function of probabilistic stress. Also it is assumed that the general stress distribution is uniform, the life distribution for the given hazard rate, $\theta$, is exponential and inverse power law model holds. In this paper, we obtained maximum likelihood estimators of model parameters and the mean life in use stress condition.

• Journal of the Korean Society of Food Culture
• /
• v.11 no.2
• /
• pp.235-242
• /
• 1996

Sanitary management practices from 8 packaged meals (Dosirak) manufacturing establishments were surveyd during production and distribution and their microbiological quality of dosirak items marketed in CVS were analyzed. Correlation coefficients were calculated to deternine significant relationships between sanitary management practices and microbiological quality of packaged meals. The results of self evaluation on sanitary management practices indicated 'doing practice well' in personnel and equipment sanitation management but time-temperature control management were practiced satisfactorily only about 55% as compared with the managerial standard guidelines. Significant relationships between the status of actual sanitary management practices and microbiological quality of Dosirak items were not found, but general status of microbiological quality of Dosirak items revealed positive relationship with the size of operational structure and the status of time-temperature control management practices.

• Proceedings of the Safety Management and Science Conference
• /
• 2000.05a
• /
• pp.249-263
• /
• 2000

This paper considers an algorithm using Johnson transformation to calculate process capability index for non-normal distribution. Johnson transformation is well known as one of methods transforming the data with non-normal distribution to normal data.