• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.4
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• pp.197-209
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• 2012

This paper studies an emergency service vehicle location problem, where minimum reliability level pre-specified at each demand point is assured. Several models are suggested depending on the busy fraction, which is the time proportion of unavailability for the ambulances. In this paper a new model on computing the busy fraction is suggested, where it varies depending on the distance between the demand point and ambulances, hence it may respond the more realistic situation. The busy fraction for the ambulance location determined by the optimization model is computed by the simulation, and updated through the iterative procedure. It has been shown that the performances of the solutions obtained by the algorithm suggested for the instances appeared in the literature.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.441-453
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• 2017

In this paper, a new type of weapon-target assignment(WTA) problem has been suggested that reflects realistic constraints for sharing target with other weapons and shooting double rapid fire. To utilize in rapidly changing actual battle field, the computation time is of great importance. Several metaheuristic methods such as Simulated Annealing, Tabu Search, Genetic Algorithm, Ant Colony Optimization, and Particle Swarm Optimization have been applied to the real-time WTA in order to find a near optimal solution. A case study with a large number of targets in consideration of the practical cases has been analyzed by the objective value of each algorithm.

• The Pure and Applied Mathematics
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• v.6 no.2
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• pp.113-120
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• 1999

This paper studies the problem of an infinite confined aquifer which at time t ＜ 0 is assumed motionless. At time t = 0 crude oil seeps into the aquifer, thereby contaminating the valuable drinking water. Since the crude oil and water are im-miscible, the problem is posed as a one-dimensional two-phase unsteady moving boundary problem. A similarity solution is developed in which the moving front parameter is obtained by Newton-Ralphson iteration. A numerical scheme, involving the front tracking method, is devised employing the fourth order Runge-Kutta method. Comparison of the exact and numerical schemes shows an error of only 3%. Thus the developed numerical scheme is quite accurate in tackling more realistic problems where exact solutions are not possible.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.69
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• pp.1-12
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• 2001

In this paper, the consumable concurred spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the operational availability maximization problem with any given fund limitation. the that the failure of a part follows a Poisson process and part failure rate is constant in spite of the decrease of number of equipments during operational period, an analytical method is developed to obtain spare part requirements using the generalized Lagrange multipliers method, The numerical examples show that analytic solution is mostly equal to the realistic solution obtained from simulation regardless of assumptions about part failure rate. It is expected that the analytical method developed in the paper can be effectively used to make a budget for provisioning the concurrent spare parts of newly procured equipment system.

• The Journal of Fisheries Business Administration
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• v.18 no.2
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• pp.53-67
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• 1987

In the fish industry, the perishabiliy of raw material, saeasonality of catch and diatance between production and consumption combine to cause physical distribution to be a difficult decision problem. In fishery physical distribution, the choice of appropriate landing port is a major problem. This paper deals with transshipment model to determine landing port as intermediate transfer point and the market to which fish should be sent. Transshipment model is useful to determine intermediate transfer point and can be reformulated as LP model. So this study developes transshipment model for korea large trawler ana analized the model output. It can be expended to a realistic problem in order to provide information to port planner and decision maker on the trade-offs between the cost and efficiency of fishery transportation.

• IE interfaces
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• v.20 no.1
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• pp.58-68
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• 2007

This research deals with a vehicle scheduling problem for the sludge collection strategies which might be solved via quantitative analysis and cost evaluations schemes. This problem can be modeled as a kind of capacitated vehicle routing pick-up problems. With the aim of establishing operation schedule of vehicles and analyzing the total cost under considering various assumptions and realistic restrictions of the sludge collection problem, we propose a heuristic method based on the genetic algorithm in conjunction with the sweep algorithm and the 4-opt algorithm. Finally, we present the cost effective operation schedule that can be used as the managing tool for the sludge treatment plant of the multi-purpose dam.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.10a
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• pp.112-133
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• 1998

The Food Problem of North Korea is well known to all of us. And we, South-Koreans, are oblidged to solve the food problem of North Korea because we should prepare and cope with the reunification of Korean Penninsula in the near future. Although many organizations of the UN (including Korea) are engaged in food-support to North Korea from the humanitarian viewpoint, a great many people are disclosed to the starvation for the food deficiency. Now how to solve the food problem of North Korea? It is the agro-cooperation between South and North Korea. The most realistic method among them is the agro-cultivation in contract.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.83-94
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• 2001

In this paper, the consumable spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the cost minimization problem with operational availability constraint. Assuming part failure rate is constant during operational period, an analytical method is developed to obtain spare part requirements. Since this solution tends to overestimate the requirements, a fast search simulation procedure is introduced to adjust it to the realistic solution. The analytical solution procedure and the simulation procedure are performed recursively until a near optimal solution is achieved. The experimental results show that the near optimal solution is approached in a fairly short amount of time.

• Journal of Elementary Mathematics Education in Korea
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• v.7 no.1
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• pp.23-44
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• 2003

The purpose of the study is to examine the phenomenon presented the process of problem solving activities of students with the mathematical context information accompanied problem based on Freudenthal's mathematizing theory and Realistic Mathematics Educations about cognitive and emotional aspects. In conclusion, taking a look at the results of study, open-ended contextual problem was had to offer in order to pull out various solutions. Teachers should help students develop their own methods, discuss their methods with others' and reinvent formal mathematics and its constructive process under the guidance of the teachers.

• Korean Security Journal
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• no.52
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• pp.127-141
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• 2017

Currently, patrol officers dispatched are required to work in pairs, and are assigned individual duties. However, despite these rules, there are still inappropriate combat education centered around dangerous weapons and arresting technique training being taught in the police system. The human rights problems resulting from excessive responses, the damages done to the patrol officers due to insufficient responses, and the judicial issues that many officers who have justly arrested face, reveal the ultimate problem of the decrease in reliability of the police. Considering this problem, there is a need for change in the current training system. Specifically, in the current dispatch rule, assignment of individual duties, and training methods, realistic improvements must be made. Having understood the arrest technique training problem and reviewed case studies of the police training in South Korea and other countries, I plan to analyze the effects of implementing a realistic and professional training system, and propose a systemic solution according to the results. By effectively discussing the various issues of the proposed training and police education, I intend to propose a realistic teamwork training for paired patrol officers, enabling them to work well together in practice and theory, hence increasing the effectiveness in crime situation.