• Journal of Biosystems Engineering
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• v.34 no.3
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• pp.183-189
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• 2009

Environmental conditions may cause the quality change of fruits during distribution after harvest. In order to prevent the damage or quality change of fruits for distribution, the characteristic of fruits affected by the environmental conditions such as temperature, humidity under various distribution conditions should be known. This research was performed to analyze how the environmental conditions affect the factors such as weight loss rate and ethylene production of the peach under several distribution conditions. Environmental conditions of the actual distributed route were evaluated and the data obtained from the conditions were used for the simulated environmental tests. Regression models of the weight loss rate and the ethylene production of peach were developed and used in predicting peach quality. The weight loss rate of the peach estimated by the ASHRAE data was shown the higher value on the transportation temperature condition than on the low and room temperature conditions. The weight loss rate and the ethylene production of the peach on the simulated distribution conditions were measured and the measured weight loss rate of peach was the smaller than the theoretically estimated one. The regression models of the weight loss rate and the ethylene production were developed respectively.

• 지반과기술
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• v.3 no.3
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• pp.15-22
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• 2006

The optimum blasting pattern to excavate a quarry efficiently and economically can be determined based on the minimum production cost, which is generally estimated according to rock fragmentation. Therefore, it is a critical problem to predict fragment size distribution of blasted rocks over an entire quarry. By comparing various prediction models, it can be ascertained that the result obtained from Kuz-Ram model relatively coincides with that of field measurements. Kuz-Ram model uses the concept of rock factor to signify conditions of rock mass such as block size, rock jointing, strength and others. For the evaluation of total production cost, it is imperative to estimate 3-D spatial distribution of rock factor for the entire quarry. In this study, a sequential indicator simulation technique is adopted for estimation of spatial distribution of rock factor due to its higher reproducibility of spatial variability and distribution models than Kriging methods. Further, this can reduce the uncertainty of predictor using distribution information of sample data. The entire quarry is classified into three types of rock mass and optimum blasting pattern is proposed for each type based on 3-D spatial distribution of rock factor. In addition, plane maps of rock factor distribution for each ground level are provided to estimate production costs for each process and to make a plan for an optimum blasting pattern.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.48-54
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• 2010

S plastic injection molding factory located at Namdong Industrial Complex in Incheon produces plastic parts for semiconductor, vacuum cleaners, office furniture, etc. It produces the parts to customers' order and delivers them directly to customers at due dates using the trucks of freight company. In recent years, it has been suffered from the excessive production cost, high lost sales rate, rigid response to customers' order, and high delivery cost, which affect negatively on its profit. This paper introduces a case study on the profit increase through a newly proposed production and distribution method which applies a make-to-stock and multi-visit delivery strategy at S plastic injection molding factory. The proposed method is evaluated by comparing with the current method with respect to sales profit using the historical data of customer demand. It is confirmed through the computational experiments that the proposed production and distribution method yields almost double increase in profit resulted from the increased production, reduced lost sales, reduced production cost, and reduced delivery cost.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.688-700
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• 2013

The potential of biodiesel production technology using lipids extracted from sewage sludge was investigated. Despite the bright prospect of biodiesel production, efforts to commercialize it have been very limited. One of the major obstacles has been the high price associated with refined oil feedstock, which makes up nearly 70-75% of the total production costs. Hence, in order to reduce the cost of biodiesel production, using cheaper feedstock such as waste oil or low-quality oil has been proposed. Especially, sewage sludge, a relatively inexpensive feedstock, is a promising raw material for such a purpose. In this study, it is aimed to review biodiesel production technology from sewage sludge as a lipid feedstock. It is process modifications to combine the oil extraction steps, fuel conversion steps (i.e. in situ transesterification, thermo-chemical process with non-catalytic heterogeneous biodiesel production) and fuel quality from sewage sludge.

• The Journal of Fisheries Business Administration
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• v.54 no.3
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• pp.29-43
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• 2023

The United States is Korea's important trading partner, ranking third (13.7%) in exports of fishery products in Korea. The impact on exports to the United States is expected to be significant if the seafood import provisions under the MMPA are implemented in 2024 accordingly. It is expected that documents proving production information will be required for all items when exporting to the U.S. Therefore, this study attempted to examine the current status of exports and exporters in order to understand the actual conditions of major fishery products exported to the United States. Besides, there are currently no official system and procedures in Korea to prove production information for all fishery items, so we tried to suggest implications by examining distribution channels for major export items to the U.S. In this study, five items including seaweed and halibut as domestic aquaculture items, tuna and squid as deep-sea fishing items, and fish cake using imported raw materials were selected as the target items for distribution channel investigation. In addition, this study is meaningful in that it investigated the routes from production to processing, distribution, and export of each item and identified detailed distribution channel for major items exported to the U.S.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.930-935
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• 2023

This study aimed to analyze the structure of the value chain of the olive flounder aquaculture industry to increase the value of this industry. Based on the value chain theory, olive flounder aquaculture industry activities were classified as primary and support activities. The primary activities included seed production, fish production, producer distribution, consumer distribution, and consumption. The support activities were production infrastructure, organization and specialization, R&D, and government policy. A survey was conducted on the costs of seed and fish production in the primary activities to investigate the business structure, and the distribution structure was analyzed to examine distribution costs and margins. In the support activities, the recent trends in R&D and government policy were mainly examined, based on which, a measure to reduce costs and maximize profits was suggested. It is necessary to reduce costs across the production processes by improving seed quality and reducing labor, feed, and management costs, which are strongly associated with support activities. Therefore, lowering costs will be possible in the olive flounder aquaculture industry when R&D outcomes, such as species development, feed quality improvement, and aquaculture system development, are stably diffused and applied in tandem with government policy regarding the industry.

• Journal of Hydrogen and New Energy
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• v.28 no.5
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• pp.584-599
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• 2017

Biodiesel is renewable, eco-friendly, clean burning diesel replacement that is consisted of short chain alkyl ester. Biodiesel is derived from the transesterification of vegetables oils or animal fats with alcohol. The process has some technical problems that must be resolved to reduce the high operation cost. Eco-friendly physical technologies by using microwave have successfully improved the transesterification for biodiesel production. This paper attempts to extensively review microwave-assisted technology for biodiesel production. Additionally, different types of catalyst for biodiesel production have been summarized. It is concluded that the microwave-assisted technique improves the reaction rate significantly in comparison with conventional methods. Therefore it can be a suitable method of reducing the reaction time and can also decreases the cost of biodiesel production.

• Journal of the Korea Society for Simulation
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• v.12 no.1
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• pp.59-71
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• 2003

Recently, a multi facility, multi product and multi period industrial problem has been widely investigated in Supply Chain Management (SCM). One of the key issues in the current SCM research area involves reducing both production and distribution costs. The purpose of this study is to determine the optimum quantity of production and transportation with minimum cost in the supply chain network. We have presented a mathematical model that deals with real world factors and constraints. Considering the complexity of solving such model, we have applied the genetic algorithm approach for solving this model using a commercial genetic algorithm based optimizer. The results for computational experiments show that the real size problems we encountered can be solved in reasonable time.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.5
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• pp.37-54
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• 2021

In this study, a customized model (CM) for the efficient operation of cold chain logistics considering the hypergeometric distribution is proposed. The CM focuses on the segmentation market of ready-to-eat foods and juices made from fresh materials. Companies should determine the amount of production by predicting consumer preferences and quantity to ensure high-efficiency production. The CM is represented as a mathematical formulation and implemented using the genetic algorithm (GA). Addition, the relative weights of CM are calculated. Further, the calculated weights are applied to the GA. In the numerical experiment, hypergeometric distribution is used to calculate the relative weights between the range of production quantities and the customized amount. Experiment results are the values of relative weights and the comparison results by average values of handling cost, total cost and CPU time. Finally, the significance of this study is summarized and a future research direction is remarked in conclusion.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.3
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• pp.27-46
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• 1992

This paper considers an (r, Q) policy for operation of a multipurpose facility. It is assumed that whenever the inventory level falls below r, the model starts to produce the fixed amount of Q. The facility can be utilized for extra production during idle periods, that is, when the inventory level is still greater than r right after a main production operation is terminated or an extra production operation is finished. But, whenever the facility is in operation for an extra production, the operation can not be terminated for the main production even though the inventory level falls below r. In the model, the demand for the product is assumed to arrive according to a compound Poisson process and the processing time required to produce a product is assumed to follow an arbitary distribution. Similarly, the orders for the extra production is assumed to accur in a Poisson process are the extra production processing time is assumed to follow an arbitrary distribution. It is further assumed that unsatisfied demands are backordered and the expected comulative amount of demands is less than that of production during each production period. Under a cost structure which includes a setup/ production cost, a linear holding cost, a linear backorder cost, a linear extra production lost sale cost, and a linear extra production profit, an expression for the expected cost per unit time for a given (r, Q) policy is obtained, and using a convex property of the cost function, a procedure to find the optimal (r, Q) policy is presented.