• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.1
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• pp.41-53
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• 2016

Static repositioning is a well-known and commonly used strategy to maximize customer satisfaction in public bike-sharing systems. Repositioning is performed by trucks at night when no customers are in the system. In models that represent the static repositioning problem, the decision variables are truck routes and the number of bikes to pick up and deliver at each rental station. To simplify the problem, the decision on the number of bikes to pick up and deliver is implicitly included in the truck routes. Two relocation-based local search algorithms (1-relocate and 2-relocate) with the best-accept strategy are incorporated into a variable neighborhood search (VNS) to obtain high-quality solutions for the problem. The performances of the VNS algorithm with the effect of local search algorithms and shaking strength are evaluated with data on Tashu public bike-sharing system operating in Daejeon, Korea. Experiments show that VNS based on the sequential execution of two local search algorithms generates good, reliable solutions.

• Proceedings of the Korean Society for Quality Management Conference
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• 2004.04a
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• pp.576-582
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• 2004

This research addresses the customers' reaction on enterprise CRM(customer relationship management) activities. Most of companies adopt CRM solution expecting revenue generation through customers' repurchasing, while customers accept to provide their personal information expecting some benefit from companies. Previous studies pointed out that many commercial organizations had difficulties yet to meet their goal of CRM due to lack of internal strategies. Moreover, the researches were focused only on companys' point of view. However, this paper finds the reason why companies' expectation does not fit and suggests the way to reduce mutual gap of expectation for successful CRM.

• Journal of the Korean Statistical Society
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• v.30 no.4
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• pp.613-635
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• 2001

This paper proposes a skewed multivariate probit model for analyzing a correlated binary response data with covariates. The proposed model is formulated by introducing an asymmetric link based upon a skewed multivariate normal distribution. The model connected to the asymmetric multivariate link, allows for flexible modeling of the correlation structure among binary responses and straightforward interpretation of the parameters. However, complex likelihood function of the model prevents us from fitting and analyzing the model analytically. Simulation-based Bayesian inference methodologies are provided to overcome the problem. We examine the suggested methods through two data sets in order to demonstrate their performances.

• Journal of the Korean Statistical Society
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• v.7 no.1
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• pp.27-43
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• 1978

This paper deals with the problem of obtaining a minimum cost acceptance sampling plan for destructive testing. The cost model is constructed under the assumption that the sampling procedure takes the following form; 1) lots rejected on the first sample are acreened with a non-destructive testing, 2) the screening is assumed to be imperfect, and therefore, after the screening, a second sample is taken to determine whether to accept the lot of to scrap it. The usual sampling procedures for destructive testing can be regarded as special cases of the above one. Utilizing Hald's Bayesian approach, procedures for finding the global optimal sampling plans are given. However, when the lot size is large, the global plan is very different to obtain even with the aid of an electronic computer. Therefore a method of finding suboptimal plan is suggested. An example with uniform prior is also given.

• Journal of Plant Biotechnology
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• v.36 no.4
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• pp.301-308
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• 2009

Higher agricultural commodity prices are a particular concern for food importing countries like Korea that has a very low self-sufficiency ratio. Korean people eat approximately 4.5 million metric tons of rice each year, which is met without a problem by domestic production. The domestic production of corn and soybean which are important raw materials for commercial food processing and livestock feed is only minimal. Demands of corn and soybean in Korea are approximately 7.2 million and 1.3 million metric tons per year, respectively. Since Korean consumers are reluctant to accept biotech (GM) foods, Korean food processors are fighting an up-hill battle in purchasing non-biotech (non- GM) crops which are becoming scarce.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.53-60
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• 2008

Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.535-546
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• 1992

The molten carbonate fuel cell(MCFC) has been under Intensive development for the last decade as a second generation fuel cell. The advantages of the MCFC over the phophoric acid fuel cell are higher efficiency, its ability to accept CO and $H_2$ as a fuel, lower material costs, and high operating temperature making internal reforming possible. These features, along with low atmospheric emissions, will open up a significant market as an attractive means of developing highly efficient power plant. This article reviews a status of the MCFC research and development, a principle of the MCFC, and cell and stack technology including the status of electrodes, matrices and electrolytes. Several technical difficulties which must be resolved to be commercialized art mainly focused.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.257-277
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• 2017

This study was conducted to suggest policy implications of providing public function of organic farming. Define the difficulties of rice farmers to provide public utility of organic farming. We estimated the amount of the farmers would like to receive for the practice of organic agriculture using choice experiment methods. By evaluating individual economic values through WTA estimates, its meaningful to grasp farmers preference for organic farming practice and conversion. These results could be used as useful data for future organic agriculture policy. For the expansion of organic farming, it is required to evaluate correct and accurate economic value and reflect this in policy.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.691-693
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• 2005

In a sender-initiated load balancing algorithm, a sender continues to send unnecessary request messages for load transfer until a receiver is found while the system load is heavy. Therefore, it yields many problems such as low cpu utilization and system throughput because of inefficient inter-processor communications until the sender receives an accept message from the receiver in this environment. This paper presents an approach based on evolutionary algorithm. The processors to which the requests are sent off are determined by the proposed algorithm to decrease unnecessary request messages.

• Journal of Korean Home Economics Education Association
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• v.8 no.2
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• pp.91-104
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• 1996

This study was to develop and to suggest a lesson plan for the area of‘Human Development and Family Relationship’in home economics for junior high school, based on Thelen’s Group Investigation Model’. Group investigation model by Thelen was developed from the theory that the education with special purpose such as societic knowledge is a method to lesson one’s conflict. This study further developed from three main concepts： inquiry, knowledge and activities of learning groups. This model can be used for any age and any subjects in order to solve the arised problems, rather than to accept pre-organized and pre-decided informations. This study is organized around activities for seeking and practicing the rages of action to create dispersal home. First, one unit ‘Understanding of Family’was chosen that concerns and suitable for group investigation model. Second, From the chosen chapter and problem were analyzed organized. Third, the chosen problem were re-analyzed, then a model lesson for group investigation was proposed.