• Journal of Applied Reliability
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• v.9 no.1
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• pp.59-69
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• 2009

LEDs have rapidly replaced old light devices such as incandescent or fluorescent lamps, and have been widely applied in general lighting, signals, automobile, signs and others. Since LEDs are for both indoor and outdoor use, temperature and humidity inevitably affect its reliability. We explain the result of the degradation life test on LEDs, and guide to reliability analysis procedure. Analysis on reliability measures are performed by Weibull++6 program, and a common shape parameter of Weibull distribution on the LED is suggested. Also, we make a description of reliability analysis procedures for the degradation data using collected test data from degradation tests. Reliability analysis procedures are consisted of estimating degradation models and failure time, verifying of distribution and parameters of the distribution, and estimating of reliability measures. Finally, this paper suggests reliability analysis method for light characteristics on LEDs.

• International Journal of Reliability and Applications
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• v.15 no.2
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• pp.111-123
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• 2014

A new class of bivariate distributions is derived by specifying its conditionals as the exponential and gamma distributions. Some properties and relations with other distributions of the new class are studied. In particular, the estimation of parameters is considered by the methods of maximum likelihood and pseudolikelihood of a special case of the new class. An application using a real bivariate data is given for illustrating the flexibility of the new class in this context, and, also, for comparing the estimation results obtained by the maximum likelihood and pseudolikelihood methods.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.3
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• pp.179-186
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• 1993

We derive the arbitrary time point system size distribution of M/ $G^{B}$1 queue in which late arrivals are not allowed to join the on-going service. The distribution is given by P(z) = $P_{4}$(z) $S^{*}$ (.lambda.-.lambda.z) where $P_{4}$ (z) is the probability generating function of the queue size and $S^{*}$(.theta.) is the Laplace-Stieltjes transform of the service time distribution function. We also derive the distribution of the service siez at arbitrary point of time. time.

• Journal of the Korean Operations Research and Management Science Society
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• v.11 no.1
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• pp.44-50
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• 1986

In this paper, we find optimal policy for the (Q, r) inventory model under the lead time uncertainty. The (Q, r) inventory model is such that the fixed order quantity Q is placed whenever the level of on hand stock reaches the reorder point r. We first develop the single level inventory model as the basis for the analysis multi-level distribution systems. The functional problem is to determine when and how much to order in order to minimize the expected total cost per unit time, which includes the set up, inventory holding and inventory shortage cost. The model, then, is extended to the multi-level distribution system consisting of the factory, warehouses and retailers. In this case, we also find an optimal policy which minimizes the total cost of the contralized multi-level distribution system.

• Journal of Korean Library and Information Science Society
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• v.33 no.2
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• pp.303-321
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• 2002

Government agency information has steadily increased as the role of government has expanded, and information provided by the government is increasingly a significant source for the public's understanding of government policy. Further, this information is an important resource for academic research oriented toward national development. However, in South Korea the distribution system for government information is far from ideal. This paper critiques that system It begins with a short history of Korean government Publishing policy, followed by a more detailed look at recent publishing trends. It then goes on to describe the legal, institutional, and technical aspects of Korean government's distribution of its information, focusing on weaknesses that prevent information from reaching those who desire or need it.

• Journal of the Korean Applied Science and Technology
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• v.30 no.3
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• pp.431-443
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• 2013

Sulfur content of diesel fuel has been cut down to under 10 ppm ULSD (ultra low sulfur diesel) level by environmental regulation with the aim of reducing exhaust emissions. This review discusses the methods and principles of sulfur reduction in diesel and presents an overview of new approaches for ultra-deep desulfurization. The deep HDS (hydrodesulfurization) problems of diesel streams is exacerbated by the inhibiting effect of co-existing aromatics, nitrogen compounds and $H_2S$. The new approaches to deep desulfurization includes non-HDS type processing schemes such as adsorptive, extractive and oxidative desulfurization.

• Journal of Distribution Science
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• v.12 no.10
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• pp.47-56
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• 2014

Purpose - This study aims to eradicate and halt the continuous life cycle of corruption. Only when ethical management policies are implemented can the business ethics system be effective and transparent. Research design, data, and methodology - The analyses and legislative measures designed by these organizations and countries were based on solid research, uncovered during my visits and interviews conducted with businessmen in those countries. Results - The main focus of in this study is as follows: First, to introduce the programs of UN, OECD, OAS, USA, and Asian countries noted for business ethics and transparency policies; Second, to define each function and problem of these countries' anti-corruption systems, including the U.S. federal government, and to examine Chinese trends. Conclusions - Ethical managements are necessary to improve business ethics. This study suggests four related areas for the purpose of discouraging bribery and corruption; these are improving global corporate governance standards, increasing financial transparency, improving good governance in the public service of the OECD member countries, and focusing on not only the supply side but also the demand side of the corruption market.

• Journal of Distribution Science
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• v.10 no.12
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• pp.19-24
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• 2012

Purpose - This paper discusses the heterogeneous fixed fleet vehicle routing problem with pick-up and delivery (HFFVRPPD), for vehicles with different capacities, fixed costs, and travel costs. Research Design, data, methodology - This paper made nine assumptions for establishing a mathematical model to describe HFFVRPPD. It established a practical mathematical model, and because of the non-deterministic polynomial-time hard (NP-hard), improved the traditional simulated annealing algorithm and tested a new algorithm using a certain scale model. Result - We calculated the minimum cost of the heterogeneous fixed fleet vehicle routing problem (HFFVRP) with a single task and, on comparing the results with the actual HFFVRP for the single task alone, observed that the total cost of HFFVRPPD reduced significantly by 46.7%. The results showed that the new algorithm provides better solutions and stability. Conclusions - This paper, by comparing the HFFVRP and HFFVRPPD results, highlights certain advantages of using HFFVRPPD in physical distribution enterprises, such as saving distribution vehicles, reducing logistics cost, and raising economic benefits.

• Journal of Nutrition and Health
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• v.31 no.1
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• pp.72-79
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• 1998

This study was intended to figure out the difference of the blood lipids, insulin and nutrients intake by fat distribution among the obese young male in Korean. Twenty-eight male college students participated in this study, whose to find out body fat distributions were classified on the basis of Waist /hip ratio (WHR) into three groups-upper body type (UBTM), intermediate body type(IBTM) and lower body type (LBTM). To conduct this study, anthropometric measurements , blood pressure, serum lipids and insulin levels, and daily nutrients intake were analized . The results are as follows : The three body type groups showed significant differences each other in waist circumference(p<0.05), WTR(p<0.001) and body fat percentage (p<0.05). Also they showed significant difference each other in the daily construction in the daily energy intake. But they did not show significant differences in the blood pressure, serum lipids and insulin levels. From the above results, we could concluded that the body fat distribution in obese the young men could affect nutrients intake pattern.

• Journal of Distribution Research
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• v.2 no.1
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• pp.183-195
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• 1997

The liberalization of Korean distribution market will undoubtedly lead to some erosion of market share of indigenous distributors in PC GMS(General Merchandising Store) & all the industries, but to our surprising, the benefits of rationalization of distribution, high qualities & low prices, strengthened competitiveness of indigenous retailers far outweigh the costs. The aim of this paper is to present some basic executive ideas for achieving a more global competitiveness in the 21st century. That is, successful market responsiveness in our distributors & firms will first of all require Dynamic Supply Chain Management at the base of information infrastructure to obtain the best competitive power. Secondly, in practical perspectives, distributors & firms needs to learn precise analysis on the basis of customer needs & wants as well as flexible thinking & proactive attitudes with respect to an freezing markets. In conclusions, win-win strategy in the competition for existence has to retain continuous & close relationship between cooperation and coordination.