• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.1
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• pp.89-95
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• 2006

Planning distributed manufacturing logistics is one of main issues in supply chain management. This paper proposes a hybrid heuristic approach for the Multi-Level, multi-item Capacitated Lot Sizing Problem (MLCLSP) in supply chain network. MLCLSP corresponds to a mixed integer programming (MIP) problem. With integer variable solutions determined by heuristic search, this MIP problem becomes linear program (LP). By repeatedly solving the relaxed MIP problems with a heuristic search method in a hybrid manner, this proposed approach allocates finite manufacturing resources fur each distributed facilities and generates feasible production plans. Meta heuristic search algorithm is presented to solve the MIP problems. The experimental test evaluates the computational performance under a variety of problem scenarios.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.403-410
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• 2009

The two-dimensional bin packing problem(2D-BPP) has been known to be NP-hard, and it is difficult to solve the problem exactly. Many approximation methods, such as genetic algorithm, simulated annealing and tabu search etc, have been also proposed to gain better solutions. However, the existing approximation algorithms, such as branch-and-bound and tabu search, have shown the low efficiency and the long execution time due to a large of iterations. To solve these problems, we first define the fitness function to simplify and increase the utility of algorithm. The function decides whether an item is packed into a given area, and as an important information for a packing strategy, the number of subarea that can accommodate a given item is obtained from the variant of the fitness function. Then we present a heuristic algorithm BF for 2D bin packing, constructed by the fitness function and subarea. Finally, the effectiveness of the proposed algorithm will be expressed by the comparison experiments with the heuristic and the metaheuristic of the literatures. As comparing with existing heuristic algorithms and metaheuristic algorithms, it has been found that the packing rate of algorithm BP is the same as 97% as existing heuristic algorithms, FFF and FBS, or better than them. Also, it has been shown the same as 86% as tabu search algorithm or better.

• Asia Marketing Journal
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• v.13 no.3
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• pp.163-182
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• 2011

The focus of this paper is to investigate cognitive development of brand heuristics in the mind of a young consumer as the consumer matures. This issue was examined by comparing the nature of the set of associations (that form the brand heuristic) given by consumers across four different age groups, with each age group representing a distinct stage of cognitive maturity. It is found that there are fundamental differences in the way the different age groups perceive the brand. The research method uses the novel approach of classifying the elicited associations into the three types of brand associations: attributes, benefits and attitudes. This classification enables comparisons of the nature of brand associations and the changes that occur as a consumer matures. To conclude, implications for theory and practice are discussed.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.304-306
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• 2002

이질적인 계산자원들로 구성된 환경에서 독립적인 작업들을 스케줄링하기 위한 최적의 방법을 찾는 것은 NP-Complete 문제로 알려져 있다 [4]. 현재까지 이 문제를 풀기 위한 다양한 휴리스틱 스케줄링 방법이 연구되어 왔다 [1, 8, 9, 10]. 작업의 선후 관계를 예측할 수 없는 상황에서는 동적 스케줄링 방법을 사용하며 동적 스케줄링 방법은 스케줄링 시기에 따라 온라인방식과 배치방식으로 나누어진다 [1, 12]. 본 논문에서는 새로운 스케줄링 알고리즘을 제안하였으며 제안된 스케줄링 알고리즘의 성능이 기존의 스케줄링 알고리즘의 성능보다 뛰어남을 실험을 통하여 보였다.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.1_2
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• pp.95-101
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• 2004

The scheduling problem that maps independent tasks to heterogeneous resources in distributed computing systems is known as NP-complete［1］. GRID［2］ is an example of distributed systems that consisted of heterogeneous resources. Many algorithms to solve this problem have been presented［1,3,4,5］. The scheduling algorithm can be classified into static scheduling algorithms and dynmic scheduling algorithms. A dynamic scheduling algorithm can be used when we can not predict the priority of tasks. Moreover, a dynamic scheduling algorithm can be divided into on-line mode algorithm and batch mode algorithm according to the scheduling time［1,6］. In this paper, we propose a new on-line mode scheduling algorithm. By extensive simulation, we can see that our scheduling algorithm outperforms previous scheduling algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.67-75
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• 2013

The advantages of the orthogonal frequency division multiplexing (OFDM) are high spectral efficiency, resiliency to RF interference, and lower multi-path distortion. To further utilize vast channel capacity of the multiuser OFDM, one has to find the efficient adaptive subchannel and bit allocation among users. In this paper, we compare the performance of the linear programming dual of the 0-1 integer programming formulation with the existing convex optimization approach for the optimal subchannel and bit allocation problem of the multiuser OFDM. Utilizing tight lower bound provided by the LP dual formulation, we develop a primal heurisitc algorithm based on the LP dual solution. The performance of the primal heuristic is compared with MAO, ESA heuristic solutions, and integer programming solution on MATLAB simulation on a system employing M-ary quadrature amplitude modulation (MQAM) assuming a frequency-selective channel consisting of three independent Rayleigh multi-paths.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.436-439
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• 2005

로봇축구는 과거의 단순한 수비시스템 벗어나 지능적 공격시스템으로 점차 변하기 시작했다. 본 논문에서는 휴리스틱 탐색기법인 최고우선탐색기법을 사용하여 공격로봇의 경험을 통해 로봇 움직임의 최적해를 찾아내고, 각 로봇간의 동기화로 인한 전술변화에 대해 설명하고 있다. 로봇이 공격과정에서 수비하는 로봇을 피해 다른 로봇에게 공을 전달하고 그 로봇이 상황에 따라 공격과 수비의 변화를 주는 방식이다. 이 알고리즘을 적용하여 최적의 로봇축구에이전트 시스템의 행동상황을 추출하고, 시뮬레이션을 통해 그 전략의 유용성을 확인한다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.1
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• pp.169-180
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• 2012

본 논문은 (1 : 1 : $N$) 재고모형에 대한 복수제품의 순환생산 및 배송 일정계획을 수립하는 연구를 수행하였다. 세부적으로 공급자가 원자재를 생산자에게 배송하면, 생산자는 순환생산방식을 활용하여 복수의 제품을 생산하여 $N$ 구매자에게 배송하는 상황을 고려하고 있다. 본 연구의 목적은 공급자, 생산자, 구매자를 포함하는 시스템 전체의 비용을 최소화하는 계획을 수립하는 것이다. 최적해가 가지는 몇 가지 특성들을 분석하고, 이를 통해서 단계적인 휴리스틱 절차를 제시할 것이다. 테스트 실험을 통해서 제시된 휴리스틱 절차가 매우 효과적이면서도 효율적이라는 점을 입증하게 될 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8B
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• pp.1487-1492
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• 2000

WDM SHR has advantages compared to SDH SHR in both cost and capacity But, wavelengths should be carefully assigned not to clash with each other and the number should be minimum. In this study, a heuristic algorithm, which is efficient in practical situations where the traffic pattern is not full-mesh or more than one wavelength is required for connecting some specific nodes, is suggested. The performance of the suggested algorithm is compared with that of the convential algorithm.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.4
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• pp.127-132
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• 2007

본 논문에서는 운송비용과 재고유지비용의 합을 최소화하는 것을 목적으로 유한 계획기간 동안의 수요를 충족시키는 동적 랏사이징 문제를 다룬다. 운송비용을 고려하는 기존의 랏사이징 모형들과는 달리 운송 트럭의 대수에 따라 계단형으로 운송비용이 증가하는 경우를 다루고 있다. 이 문제를 선형정수모형으로 모델링하며 그리디 방식의 휴리스틱을 제안한다. 제안된 휴리스틱의 성능을 평가하기 위해 계산실험을 수행하며, 그 결과 매우 짧은 시간 안에 최적해에 가까운 해를 찾을 수 있음을 보여준다.