• 한국국방경영분석학회지
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• 제30권1호
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• pp.1-14
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• 2004

In this paper, we propose a new data-mining-based methodology for military occupational specialty assignment. The proposed methodology consists of two phases, feature selection and man-power assignment. In the first phase, the k-means partitioning algorithm and the optimal variable weighting algorithm are used to determine attribute weights. We address limitations of the optimal variable weighting algorithm and suggest a quadratic programming model that can handle categorical variables and non-contributory trivial variables. In the second phase, we present an integer programming model to deal with a man-power assignment problem. In the model, constraints on demand-supply requirements and training capacity are considered. Moreover, the attribute weights obtained in the first phase for each specialty are used to measure dissimilarity. Results of a computational experiment using real-world data are provided along with some analysis.

• 한국인터넷방송통신학회논문지
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• 제22권3호
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• pp.177-183
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• 2022

2차원 할당 문제는 다항시간 알고리즘이 알려지지 않은 NP-완전 문제이다. 본 논문은 위치간 거리가 일정하지 않은 랜덤형 2차원 할당 문제의 최적 해를 O(n²) 수행 복잡도로 찾을 수 있는 알고리즘을 제안하였다. 제안된 알고리즘은 위치 행렬 L에서의 최소 거리 합 위치 l_i와 시설 행렬 F에서의 최대 물동량 시설 f_j를 M={(l_i,f_j)}으로 매치키시고, M을 기준으로 최소 거리 합 l_i와 시설 행렬 F에서의 최대 물동량 시설 f_j의 매칭 쌍 (l_i,f_j)을 점진적으로 증대시키는 전략을 수행하고, 위치별 거리와 시설별 물동량 상관관계를 최적으로 반영하기 위해 시설들을 교환하는 전략을 적용하였다. 실험 데이터에 적용한 결과, 제안 알고리즘은 O(n²) 의 다항시간 알고리즘임에도 불구하고 메타휴리스틱 방법의 일종인 유전자 알고리즘의 해를 개선할 수 있었다.

• 한국산업정보학회논문지
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• 제2권2호
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• pp.87-103
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• 1997

설비 배치는 기업의 장단기 생산능력 효율에 상당한 영향을 미치므로 제품 및 서비스의 생산에 있어 최대의 효율을 올릴 수 있도록 배치되어야 하나, 최적의 설비 배치안을 찾는다는 것은 매우 어려운 일이다. 이러한 설비 배치 문제는 이차할당문제(Quadratic Assignment Problem : QAP)로 모형화할 수 있으며, 이의 해결을 위해 일반적으로 휴리스틱 알고리즘은 전통적인 검색 기법에 비해 우위에 있는 것으로 알려지고 있다. 따라서 본 연구에서는 설비 배치 문제의 해결을 위하여 유전 알고리즘의 개발을 시도하였으며, 선행 연구들과의 비교 분석 결과 기존 연구들에 비해 더 우수한 해을 제시할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.324-327
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• 1996

This paper describes the robust controller design methods applied to the problem of an automatic system for tow-vehicle/trailer combinations. This study followed an inverse Linear Quadratic Regulator(LQR) approach which combines pole assignment methods with conventional LOR methods. It overcomes two concerns associated with these separate methods. It overcomes the robustness problems associated with pole placement methods and trial and error required in the application of the LQR problem. Moreover, a Kalman filter is used as the observer, but is modified by using the loop transfer recovery (LTR) technique with modified transmission zero assignment. The proposed inverse LQG,/LTR controllers enhances the forward motion stability and maneuverability of the combination vehicles. At high speeds, where the inherent yaw damping of the vehicle system decreases, the controller operates to maintain an adequate level of yaw damping. At backward moton, both 4WS (2WS tow-vehicle, 2WS trailer) and 6WS (4WS tow-vehicle, 2WS trailer) control laws are proposed by using inverse LQG/LTR method. To evaluate the stability and robustness of the proposed controllers, simulations for both forward and backward motion were conducted using a detailed nonlinear model. The proposed controllers are significantly more robust than the previous controllers and continues to operate effectively in spite of parameter perturbations that would cause previous controllers to enters limit cycles or to loose stability.

• Journal of Communications and Networks
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• 제16권4호
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• pp.430-435
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• 2014

The performance of a distributed database system depends particularly on the site-allocation of the fragments. Queries access different fragments among the sites, and an originating site exists for each query. A data allocation algorithm should distribute the fragments to minimize the transfer and settlement costs of executing the query plans. The primary cost for a data allocation algorithm is the cost of the data transmission across the network. The data allocation problem in a distributed database is NP-complete, and scalable evolutionary algorithms were developed to minimize the execution costs of the query plans. In this paper, quadratic assignment problem heuristics were designed and implemented for the data allocation problem. The proposed algorithms find near-optimal solutions for the data allocation problem. In addition to the fast ant colony, robust tabu search, and genetic algorithm solutions to this problem, we propose a fast and scalable hybrid genetic multi-start tabu search algorithm that outperforms the other well-known heuristics in terms of execution time and solution quality.

• 호남수학학술지
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• 제28권2호
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• pp.185-196
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• 2006

A scheme based on the cryptography for enforcing multilevel security in a system where hierarchy is represented by a partially ordered set was first introduced by Akl et al. But the key generation algorithm of Akl et al. is infeasible when there is a large number of users. In 1985, MacKinnon et al. proposed a paper containing a condition which prevents cooperative attacks and optimizes the assignment in order to overcome this shortage. In 2005, Kim et al. proposed key management systems for multilevel security using one-way hash function, RSA algorithm, Poset dimension and Clifford semigroup in the context of modern cryptography. In particular, the key management system using Clifford semigroup of imaginary quadratic non-maximal orders is based on the fact that the computation of a key ideal $K_0$ from an ideal $EK_0$ seems to be difficult unless E is equivalent to O. We, in this paper, show that computing preimages under the bonding homomorphism is not difficult, and that the multilevel cryptosystem based on the Clifford semigroup is insecure and improper to the key management system.

• 대한전자공학회논문지SD
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• 제37권2호
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• pp.65-77
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• 2000

본 논문에서는 IC(Integrated Circuits) 칩들간의 배선 위상(topology)이 정해진 재구성 가능한(reconfigurable) FPGA(Field Programmable Gate Array) 기반 보드로의 회로 분할 문제로써 새로운 quadratic boolean programming 수식(formulation)을 제안한다. 본 수식의 목적은 회로 분할 시 사용하는 핀수와 네트들의 배선 길이의 합을 최소화하는 것이며 기존의 분할 방법에서 고려하는 제약조건 외에 서로 인접하지 않은 IC 칩들을 연결하기 위하여 다른 IC 칩을 통과(pass through)하는 네트들에 의해 사용되는 핀수도 고려한다. 또한 본 논문에서는 제안한 분할 문제를 효율적으로 해결하기 위하여 모듈 할당 방법으로 구성되어 있는 휴리스틱(heuristic) 분할 방법을 제안한다. 입력된 회로에 대하여 다른 분할 방법과 비교하여 실험한 결과 분할 문제의 주어진 제한들을 모두 만족하였다. 대부분의 배선된 회로에 대하여 핀 사용률이 적게 나타났으며 네트들의 사용한 배선 길이의 합은 최대 34.7% 적게 나타났다.

• 대한기계학회논문집
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• 제18권8호
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• pp.1985-1996
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• 1994

A new design method of sliding hyperplanes is proposed in the synthesis of a variable structure controller for robust tracking of general nonlinear multi-input-output(MIMO) uncertain systems of relative degree higher than two. Input/ output(I/O) linearzation is firstly undertaken by employing the concept of relative degree and minimum phase followed by the construction of sliding mode controllers. Sliding hyperplanes are then derived from the inherent properties of companion matrix and ideal sliding mode characterized in I/O linearized system. Subsequently, the gradient magnitudes of the sling hyperplanes are determined in an optimal manner by considering a quadratic performance index to be evaluated at two phases; a reaching phase and a sliding phase. The proposed design methodology is relatively straightforward and systematic compared with conventional strategies such as geometric approach or pole assignment technique. A nonlinear governor and exciter control problem for a power system is adopted herein in order to demonstrate the design efficiency and also favorable and robust control performances.