• The Journal of Fisheries Business Administration
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• v.46 no.3
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• pp.129-141
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• 2015

Because land based aquaculture is restricted by high investment per rearing volume and control cost, good management planning is important in Land-based aquaculture system case. In this paper master production planning was made to decide the number of rearing, production schedule and efficient allocation of water resources considering biological and economic condition. The purpose of this article is to build the mathematical decision making model that finds the value of decision variable to maximize profit under the constraints. Stocking and harvesting decisions that are made by master production planning are affected by the price system, feed cost, labour cost, power cost and investment cost. To solve the proposed mathematical model, heuristic search algorithm is proposed. The model Input variables are (1) the fish price (2) the fish growth rate (3) critical standing corp (4) labour cost (5) power cost (6) feed coefficient (7) fixed cost. The model outputs are (1) number of rearing fish (2) sales price (3) efficient allocation of water pool.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.45-52
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• 2009

The objective of this was to improve a transportation cost relation between Central Distribution Centers(CDCs) and Regional Distribution Centers(RDCs), to control inventory cost concerning safety stock for each service level, by reviewing distribution steps connecting CDCs and RDCs under the price discount. It was also to examine and compare operating costs for the following two alternative suggestions for setting the service standard as a counter measure for a stock-out of the distribution network system management. First, provision by dispersing the safety stock to the CDCs and RDCs; and second, exclusive provision of the safety stock only to the RDCs. The cost comparison analysis was made for each category of purchase costs, regular transportation costs, express transportation costs, and inventory holding costs.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.813-825
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• 2019

This paper investigated the effects of a government production and shipment stabilization policy and the improvement plan for vegetables in Korea. In this study, a simulation focused on the changes in farm income for Chinese cabbages & radishes using scenarios. The result shows an increase in farm income according to the government policy. In the short-term, demand and supply are fixed, and the policy effect is positive due to the price support effect of the project. However, for mid- to long-term, the price decreases due to the expansion of supply by business beneficiaries, which is likely to be adversely affected by an unstable supply and demand. This increases the burden of government and local government subsidies. This phenomenon is expected to be amplified as the ratio of production and shipbuilding stabilization programs and items expand. When expanding items and adjusting and setting the percentage of participation in the project, it is desirable to set and operate the appropriate business ratio taking into consideration the demand. To improve the effectiveness of the policy, the following remedies were suggested. First, national supply and demand guidelines should be set up, and the autonomous supply and demand control of the producers should be guided by the different preservation according to the implementation of the supply and demand control obligation. As for detailed equipment, it is necessary to establish the reproduction price for each item, set the base price for each wholesale market, increase the incentive for the producers to participate, and fund a business budget to secure business stability.

• Journal of Korean Society for Quality Management
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• v.7 no.1
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• pp.15-25
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• 1979

Recently ('70~'76) the average annual export expansion rate was 31.7% (the foremost rate in the world). In '77 the export amounted to 10 billion dollars, and 12.7 billion dollars in '78. The tendeney has been to increase yearly. In view of the structure of export goods, the major export products have been changed from primary industrial materials (86% of the total export in '76) to industrial products (82% in '75). These trends are due to the remarkable progress in the technology advancement. Only 33.6% of the total export items can compete with those of advanced industrial countries in both of price and non-price competitiveness, therefore ours stand in weak position to that of advanced industrial countries. In order to promote good will and strengthen international competitiveness, the major stress of this paper is first of all on the problems of Quality Control, which covers the present states and derived problems of Quality control. These are investigated and analyzed to insure the rational application of Quality Control to the major export goods with a view of the establishment of the direction and systematic improving means of Quality Control.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.3
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• pp.35-45
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• 2006

Fallow paddy areas have been increased due to the import of cheap agricultural product, and the unbalance between farming cost and rice price since 1990. In domestic, rice production control that decrease paddy field area has been introduced for the control of rice demand and supply and stabilization of rice price since 2003. Because of the desire of paddy field's owner to create benefit by using paddy for other object, fallow paddy would be continuously increased. In the other aspect, many people in the world is suffering from hunger because of the shortage of food. In case of Korea, continuous drought and flood damages will be potential concern of stable food supply. From this viewpoint, the increasing fallow paddy area needs to be protected from the devastation by weed breeding for the re-cultivation. In this study, fallow paddy managed with the shallow pools and shallows was selected fur monitoring and analyzing of water quality and plant body change. As the results, the managed fallow paddy found to be effective in the purification of water quality and the control of plant growth.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.436-445
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• 2013

The use of a demand response controller is necessary for electric devices to effectively respond to time varying price signals and to achieve the benefits of cost reduction. This paper describes a new formulation with the form of constrained optimization for designing an optimal demand response controller. It is demonstrated that constrained optimization is a better approach for the demand response controller, in terms of the ambiguity of device operation and the practicality of implementation of the optimal control law. This paper also proposes a design scheme to construct a demand response controller that is useful when a system controller is already adapted or optimized for the system. The design separates the demand response function from the original system control function while leaving the system control law unchanged. The proposed formulation is simulated and compared to the system with simple dynamics. The effects of the constraints, the system characteristics and the electricity price are examined further.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1388-1392
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• 2013

Electric scooter has been using short-lived, low-efficiency DC motor. And motor control system is equipped with imported uniformly, so there is no product differentiation. Also, product design according to the characteristics of disability is difficult. In this study, BLDC motor control system to specialize in a electric scooter for disabled was developed with a semi-permanent features of life, low price, and high performance. This development will also contribute to the activation of the related industries, as well as be able to secure price competitiveness of domestic electric scooter.

• Spatial Information Research
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• v.10 no.2
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• pp.215-232
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• 2002

Variables representing neighborhood quality should be included in hedonic price models to control lfor the influences of negative or positive externalities from the quality of neighborhood on urban housing prices. This study proposes a GIS-based method to effectively measure the neighborhood quality variable when data on the neighborhood quality are aggregated by census sub area. This study also tests the superiority of the proposed neighborhood quality variable created by intensive use of GIS operations to a neighborhood variable not based on GIS operations in explaining the housing price variations by using Seoul＇s apartment sales data. The results from this study show that the neighborhood quality variable based on GIS-based operations shows better performance in explaining the urban housing price variations in Seoul＇s housing market. The implication from the results is that the potentials of GIS-based spatial operations in creating neighborhood quality variables should be well acknowledged by the researchers in the area of urban housing market study and GIS-based spatial operations should be more actively applied to generate better neighborhood quality variables for hedonic price models.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.3
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• pp.262-268
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• 2020

The IMO (International Maritime Organization) has mandated the restriction of SOx emissions to 0.5 % for all international sailing vessels since January 2020. And, a number of countries have designated emission control areas for stricter environmental regulations. Three representative methods have been suggested to cope with these regulations; using low-sulphur oil, installing a scrubber, or using LNG (Liquefied Natural Gas) as fuel. In this paper, economic analysis was performed by comparing the method of installing a scrubber with the method of using low-sulphur oil without installing additional equipment. We suggested plausible layouts and compared the pros and cons of dif erent scrubber types for retrofitting. We selected an international sailing ship as the target vessel and estimated payback time and benefits based on navigation route, fuel consumption, and installation and operation costs. Two case of oil prices were analyzed considering the uncertainty of fuel oil price fluctuation. We found that the expected payback time of investment varies from 1 year to 3.5 years depending on the operation ratio of emission control areas and the fuel oil price change.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.938-946
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• 2005

We study the firm's strategy to price its products and plan the spare parts manufacturing so as to maximize its profit and at the same time to fulfill its commitment to providing the customers with the key parts continuously over the relevant decision time horizon, i.e., the production plus warrantee period. To examine the research question, we developed and solved a two-stage optimal control theory model. Our analysis suggests that if the cost to produce the spare part during the warrantee period is more expensive than that during the production period, the firm should increase its sales price gradually throughout the production period to control its sales. In addition, during the production period it is optimal for the firm to produce the spare parts more than needed so that the overproduced spare parts can be used to partially meet the demand during the warrantee period. We conducted numerical analysis to investigate the sensitivity dynamics among key variables and parameters such as inventory holding cost, unit spare part production costs, part failure rate, and parameters in the demand function.