• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.138-147
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• 2011

Modeling fishing-gear systems is essential to better understand the factors affecting their movement and for devising strategies to control movement. In this study, we present a generalized mathematical modeling methodology to analyze fishing gear and its various components. Fishing gear can be divided into a finite number of elements that are connected with flexible lines. We use an algorithm to develop a numerical method that calculates precisely the shape and movement of the gear. Fishinggear mathematical models have been used to develop software tools that can design and simulate dynamic movement of novel fishing-gear systems. The tool allowed us to predict the shape and motion of the gear based on changes in operation and gear design parameters. Furthermore, the tool accurately calculated the swept volume of towed gear and the surrounding volume of purse-seine gear. We analyzed the fished volume for trawl and purse-seine gear and proposed a new definition of fishing effort, incorporating the concept of fished space. This method may be useful for quantitative fishery research, which requires a good understanding of the selectivity and efficiency of fishing gear used in surveys.

• Korean System Dynamics Review
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• v.1 no.2
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• pp.113-148
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• 2000

In 1987, The Brundtland Report defined a sustainable development as the development that meets the needs of the present without compromising the ability of future generations to meet their own needs. This is the concept that we should cling to, to preserve natural resources of the present for the future generation. With this concept in mind, this paper criticized the current waste management policy has been neglecting resource preservation aspect of waste management policy while giving too much emphasis on reducing waste generation. Thus, the purpose of this paper is to analyze how waste management policy can affect preservation of natural resources, and to investigate policy alternatives that can reduce both the volume of wast geverated and the amount of natural resources that need to be consumed in the production process. The study was conducted based on the literature survey and system dynamics simulation. Borrowing Randers and Meadows's solid waste model with some modification of parameter and variables, this paper simulate several policy alternatives to figure out the most effective waste management policy set that can meet the need of the present without compromising the ability of the future generation to meet their own needs. Main concern was how to link waste management policy with resource management policy that can lead to minimization of waste generation and resource consumption.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.260-267
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• 2017

Quantum-inspired Genetic Algorithm (QGA) is a probabilistic search optimization method combined quantum computation and genetic algorithm. In QGA, the chromosomes are encoded by qubits and are updated by quantum rotation gates, which can achieve a genetic search. Asset-based weapon target assignment (WTA) problem can be described as an optimization problem in which the defenders assign the weapons to hostile targets in order to maximize the value of a group of surviving assets threatened by the targets. It has already been proven that the WTA problem is NP-complete. In this study, we propose a QGA and a hybrid-QGA to solve an asset-based WTA problem. In the proposed QGA, a set of probabilistic superposition of qubits are coded and collapsed into a target number. Q-gate updating strategy is also used for search guidance. The hybrid-QGA is generated by incorporating both the random search capability of QGA and the evolution capability of genetic algorithm (GA). To observe the performance of each algorithm, we construct three synthetic WTA problems and check how each algorithm works on them. Simulation results show that all of the algorithm have good quality of solutions. Since the difference among mean resulting value is within 2%, we run the nonparametric pairwise Wilcoxon rank sum test for testing the equality of the means among the results. The Wilcoxon test reveals that GA has better quality than the others. In contrast, the simulation results indicate that hybrid-QGA and QGA is much faster than GA for the production of the same number of generations.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.37-43
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• 2001

Crop status monitoring and yield prediction at higher spatial resolution is a valuable tool in various decision making processes including agricultural policy making by the national and local governments. A prototype crop forecasting system was developed to project the size of rice crop across geographic areas nationwide, based on daily weather pattern. The system consists of crop models and the input data for 1,455 cultivation zone units (the smallest administrative unit of local government in South Korea called "Myun") making up the coterminous South Korea. CERES-rice, a rice crop growth simulation model, was tuned to have genetic characteristics pertinent to domestic cultivars. Daily maximum/minimum temperature, solar radiation, and precipitation surface on 1km by 1km grid spacing were prepared by a spatial interpolation of 63 point observations from the Korea Meteorological Administration network. Spatial mean weather data were derived for each Myun and transformed to the model input format. Soil characteristics and management information at each Myun were available from the Rural Development Administration. The system was applied to the forecasting of national rice production for the recent 3 years (1997 to 1999). The model was run with the past weather data as of September 15 each year, which is about a month earlier than the actual harvest date. Simulated yields of 1,455 Myuns were grouped into 162 counties by acreage-weighted summation to enable the validation, since the official production statistics from the Ministry of Agriculture and Forestry is on the county basis. Forecast yields were less sensitive to the changes in annual climate than the reported yields and there was a relatively weak correlation between the forecast and the reported yields. However, the projected size of rice crop at each county, which was obtained by multiplication of the mean yield with the acreage, was close to the reported production with the $r^2$ values higher than 0.97 in all three years.

• Proceedings of the Korean System Dynamics Society
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• 2000.07a
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• pp.65-102
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• 2000

In 1987, The Brundtland Report defined a sustainable development as the development that meets the needs of the present without compromising the ability of future generations to meet their own needs. This is the concept that we should cling to, to preserve natural resources of the present for the future generation. With this concept in mind, this paper criticized that the current waste management policy has been neglecting resource preservation aspect of waste management policy while giving too much emphasis on reducing waste generation. Thus, the purpose of this paper is to analyze how waste management policy can affect preservation of natural resources, and to investigate policy alternatives that can reduce both the volume of waste generated and the amount of natural resources that need to be consumed in the production process. The study was conducted based on the literature survey and system dynamics simulation. Borrowing Randers and Meadows's solid waste model with some modification of parameter and variables, this paper simulate several policy alternatives to figure out the most effective waste management policy set that can meet the need of the present without compromising the ability of the future generation to meet their own needs. Main concern was how to link waste management policy with resource management policy that can lead to minimization of waste generation and resource consumption.

• Journal of Construction Engineering and Project Management
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• v.3 no.3
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• pp.10-16
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• 2013

The annual expenditure on diesel oil and heavy oil in the construction sector is the second largest among all industrial sectors. According to the greenhouse reduction scheme of Korean Government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Most researches on environmental issues focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction sites. This research regards the operation of equipment for the on-site construction processes as a system and attempts to model the energy use processes related to the activities in construction sites, and provides simulation results of earth excavation and hauling processes. The result of this research is expected to aid construction planners estimating the time-based patterns of energy use and assessing greenhouse gas emission and to help selecting more energy efficient alternatives at the planning stage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.179-185
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• 2012

When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize casting design of an automobile part (Gear Box) Computer Aided Engineering (CAE) was performed by using the simulation software (Z Cast). The simulation results were analyzed and compared with experimental results. During the mold filling, internal porosities caused by air entrap were predicted and reduced remarkably by the modification of the gate system and the configuration of overflow. With the solidification analysis, internal porosities caused by the solidification shrinkage were predicted and reduced by the modification of the gate system. For making a better production die casting tool, cooling systems on several thick areas are proposed in order to reduce internal porosities caused by the solidification shrinkage.

• Journal of Environmental Science International
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• v.10 no.2
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• pp.91-97
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• 2001

A macroeconomic minimodel was simulated to analyze the effect of global exchange on the Korea\\`s economy. The simulation results illustrate some of the consequences of public policy and some insight into current world problems. All computer simulation runs made under various conditions suggest that the Korea\\`s system in the near future may be strongly influenced by the favorable availability of outside resources, while the national power and assets may be declined by indigenous environmental stock depletion. The borrowed capital allows the temporary money stock to increase and the national assets to grow faster and a little higher, as using up the environmental resources more quickly. Later, when the debt is paid off, the foreign exchange holdings may not go so high. For the environmentally sound and sustainable development, over 75% of total economic production should be invested to the natural resource management. Therefore, the economic structure of Korea should be transferred from the present industrial structure to social-economic structure based on ecological-recycling concept.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.287-293
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• 2013

The annual expenditure on diesel oil and heavy oil in the construction sector is the second largest among all industrial sectors. According to the greenhouse reduction scheme of Korean Government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Most researches on environmental issues focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction sites. This research regards the operation of equipment for the on-site construction processes as a system and attempts to model the energy use processes related to the activities in construction sites, and provides simulation results of earth excavation and hauling processes. The result of this research is expected to aid construction planners estimating the time-based patterns of energy use and assessing greenhouse gas emission and to help selecting more energy efficient alternatives at the planning stage.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.1
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• pp.43-56
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• 2009

The Korean navy has made many efforts to apply the concepts of PLM (Product Lifecycle Management) and M&S to its naval design and production. However, most of the efforts that have being applied to some acquisition processes, focused only on the element technologies without information models and data frameworks. This study discusses an information model of naval ships for advanced naval acquisitions. We introduce a naval ship product model, and it refers to the DPD (Distributed Product Description) concept of SBA (Simulation-Based Acquisition). To realize the product model concept, we design a data architecture and develop a Product Model Management System (PMMS) based on a PDM System. It is validated through the case study of building the product model of the battle ship that the PMMS has the applicability to effectively manage the naval ship acquisition data on the basis of a 3D product model.