• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.09a
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• pp.119-124
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• 1995

물류네트워크에서 다루는 문제들은 물류거점의 입지문제, 물류거점의 재고문 제, 수배송문제로 크게 분류해 볼수 있으며 특히 이들 각 문제들은 복합적으 로 관련되어 있는 것이 사실이다. 이러한 물류네트워크모형을 수리적으로 표 현해보면 대규모 혼합 정수계획법이 되어 최적 해를 구하기가 매우 어려울 뿐더러 현실적으로 유리된 가정이 불가피하다. 수리모형의 비현실적인 가정 들을 가능한 줄이고 현실적으로 응용 가능한 방법론을 제시하는 것이 본 연 구의 목적이다. 때문에 단일 최적 해를 찾는 수리계획법 대신 대안별로 분 석.비교평가 할 수 있는 네트워크 시뮬레이션 기법을 이용하였다. 평가척도 는 비용인자와 서비스 수준을 이용하지만 시뮬레이션 기법의 유연성으로 인 해 다양한 평가인자를 접목시킬수 있는 가능성을 제공하였다. 현실성과 실용 성에 주안을 둔 본 연구는 프로그래밍 되어 분석 및 계획수립과정에 활용되 어질수 있다.

• Information Systems Review
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• v.5 no.2
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• pp.203-217
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• 2003

Constraint Programming and Optimization have developed in different fields to solve common problems in real world. In particular, constraint propagation and linear Programming are their own fundamental and complementary techniques with the potential for integration to benefit each other. This intersection has evoked the efforts to combine both for a solution method to combinatorial optimization problems. Attempts to combine them have mainly focused on incorporating either technique into the framework of the other with traditional models left intact. This paper argues that integrating both techniques into an old modeling fame loses advantages from another and the integration should be molded in a new framework to be able to exploit advantages from both. The paper propose a declarative modeling framework in which the structure of the constraints indicates how constraint programming and optimization solvers can interact to solve problems.

• Journal of Navigation and Port Research
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• v.30 no.6 s.112
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• pp.457-464
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• 2006

Remarshalling operation is one of the operations considered important in an automated container terminal to perform quickly loading operations and delivery operations. It arranges the containers scattered at a verticla yard block in order to reduce the transfer time and the rehandling time of ATC(Automated Transfer Crane)s. This paper deals with the remarshalling planning problem minimizing the weighted operation time. This problem can be decomposed into 2 subproblems, storage space assignment problem and operation sequencing problem Storage space assignment problem decides to where containers are transported in terms of transportation time cost.. With results of a previous subproblem, operation sequence problem determines the ATC operation sequence, which minimizes the dead-heading of ATC This study formulates each subproblem with mixed integer program and dynamic program. To illustrate the proposed model, we propose an instance to explain the process of remarshalling planning.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.255-264
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• 2021

In this paper, we propose operations and maintenance (O&M) planning approach for floating offshore wind farm using the mathematical optimization. To be specific, we present a MILP (Mixed Integer Linear Programming that suggests the composition of vessels, technicians, and maintenance works on a weekly basis. We reflect accessibility to wind turbines based on weather data and loss of power generation using the Jensen wake model to identify downtime cost that vary from time to time. This paper also includes a description of two-stage approach for maintenance planning & detailed scheduling and numeric analysis of the number of vessels and technicians on the O&M cost. Finally, the MILP model could be utilized in order to establish the suitable and effective maintenance planning reflecting domestic situation.

• Resources Recycling
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• v.16 no.6
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• pp.10-19
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• 2007

The mechanical process followed by hydrometallurgical treatment has been developed in order to recover cobalt and lithium from spent lithium ion battery. In the previous study, a citrate precursor combustion process to prepare cathodic active materials from the leaching solution was elucidated. Resynthesis of electrode materials should be more valuable in spent battery recycling. Conventional slurry mixing of $LiCoO_2$ and carbon cannot make uniform distribution, and therefore the cathode cannot reach the theoretical charge-discharge capacity and is easily degraded during the charge-discharge cycling. In this study, ultra-fine $LiCoO_2$ powders has been prepared by modification of the combustion process and fabricated the enhanced cathode by modification of mixing method of $LiCoO_2$ and carbon added.

• Geotechnical Engineering
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• v.12 no.3
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• pp.109-126
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• 1996

In this study, the chemical fluid considered is sodium chloride sloutions. The concentrations for the sodium chloride solutions are varied from 0 to 20%. A series of lab oratory triaxial tests are performed on the cylindrical specimens of sand bentonite mixture with different (5, 10, 15%) sodium chloride content solutions. Deformation(elastic modulus, E) and strength (cohesion, c', and angle of friction, f') parameters are obtained from the triaxial tests and they are expressed as functions of conf'ming pressure and sodium chloride solution concentrations. The stress-strain-strength behavior based on the above strength parameters is introduced to the finite element method with a residual flow procedure (RFP). By integrating a slope stability (limit equilibrium) procedure in the finite element method, factors of safety with time are computed.

• Journal of the military operations research society of Korea
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• v.34 no.3
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• pp.1-12
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• 2008

Design of supply chain network (SCN) is required to optimize every factor in SCN and to provide a long-term and strategic decision-making. A mathematical model can not reflect the real world because design of SCN contains variables and stochastic factors according to status of its system. This paper presents the designing methodology of military SCN using the mathematical model and the simulation model. It constructs SCN to minimize its total costs using the Mixed Integer Programming (MIP) model. And we solve problems of a vehicle assignment and routing through adaptation of experiment parameters repeatedly in the simulation model based on the results from the MIP model. We implement each model with CPLEX and AutoMod, and experiment to reconstruct SCN when the Logistic Support Unit is restricted to support military units. The results from these experiments show that the proposed method can be used for a design of military SCN.

• Journal of Korean Society of Transportation
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• v.19 no.3
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• pp.75-88
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• 2001

Signal optimization model for alternative use of lanes at a signalized intersection with an stop-line added backward was presented in this paper. The simulation results shot-ed that the traffic fed from the stop-line passed the intersection in each specified phasing interval for left and through traffic. The experimental results indicated that the proposed model was much superior to traditional signal optimization methodology in reducing delay, fuel consumption, and disutility index for delay and stops. The effects for reducing delay were greater than those for doing fuel consumption and disutility index due to the added stop-line. The proposed model is expected to alleviate traffic congestion at intersections, both which have no left turn pocket, and which have large left turn volume. The model is recommended to adapted for intersections spaced long among them with no near driveway.

• Journal of the Korean Geographical Society
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• v.49 no.3
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• pp.423-437
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• 2014

Districting is a spatial decision making process to make a new regional framework for affecting human activities. Natural barriers such as rivers and mountains located within a reorganized district may reduce the efficiency of reorganized human activities. This implies that it is necessary to consider boundary characteristics in a districting process. The purpose of this research is to develop a new spatial optimization model based on boundary characteristics for districting problems. The boundary characteristics are evaluated as continuous value expressing the possibility of combining adjacent two basic spatial units rather than a dichotomous value with 1 or 0 and are defined as an objective function in the model. In addition, the model has explicitly formulated contiguity constraints as well as constraints enforcing demand balance among districts such as population and area. The boundary attributes are categorized into physical and relational characteristics. Suitability analysis is used to combine various variables related to each boundary characteristic and to evaluate the coupling possibility between two neighboring basic units. The model is applied to an administrative redistricting problem. The analytical results demonstrate that various boundary characteristics could be modeled in terms of mixed integer programming (MIP).

• Journal of Navigation and Port Research
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• v.35 no.8
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• pp.657-665
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• 2011

This study deals with an integrated problem for deciding sequencing and storage location of export containers together at its receiving operation in the container terminal with a perpendicular layout. The preferred storage location of an export container varies with the priority of the corresponding loading operation and the waiting time of an external truck depends on its storage time. This paper proposes the mixed integer programming model considering the expected arrival time and expected finish time of an external truck and the preferred storage location for its loading operation. And we suggest the heuristic algorithm based on a simulated annealing algorithm for real world adaption. We compare the heuristic algorithm with the optimum model in terms of the computation times and total cost and the performance of the heuristic algorithm is analyzed through a numerical experiment.