• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.809-819
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• 2000

This paper deals with an optimal capacity allocation problem and performance analysis in Advanced Information Communication Processing System(AICPS). AICPS is a gateway system interconnection PSTN(Public Switched Telephone Network), ISDN(Intergrated Services Digital Network), PSDN(Packet Switched Data Network), internet, Frame Relay and ATM together. This study considers not only ISDN and Internet but also user behavior of On-line service which is analyzed by Markov process. A call blocking probability of TNAS and INAS is computed by Erlang's formula. Then, PNAS and WNAS's call blocking probability are computed by Stochastic knapsack modeling. The result is compared with result of simulation. Finally, we allocate an optimal capacity minimizing total call blocking probability.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.2
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• pp.3-13
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• 1993

In this study, we develop a B & B type algorithm for the concave minimization problem with 0-1 knapsack constraint. Our algorithm reformulates the original problem into the singly linearly constrained concave minimization problem by relaxing 0-1 integer constraint in order to get a lower bound. But this relaxed problem is the concave minimization problem known as NP-hard. Thus the linear function that underestimates the concave objective function over the given domain set is introduced. The introduction of this function bears the following important meanings. Firstly, we can efficiently calculate the lower bound of the optimal object value using the conventional convex optimization methods. Secondly, the above linear function like the concave objective function generates the vertices of the relaxed solution set of the subproblem, which is used to update the upper bound. The fact that the linear underestimating function is uniquely determined over a given simplex enables us to fix underestimating function by considering the simplex containing the relaxed solution set. The initial containing simplex that is the intersection of the linear constraint and the nonnegative orthant is sequentially partitioned into the subsimplices which are related to subproblems.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.3
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• pp.37-58
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• 1997

An AI approach with tabu search is designed to solve multi-level knapsack problems. The approach performs intelligent actions with memories of historic data and learning effect. These action are developed ont only by observing the attributes of the optimal solution, the solution space, and its corresponding path to the optimal, but also by applying human intelligence, experience, and intuition with respect to the search strategies. The approach intensifies, or diversifies the search process appropriately in time and space. In order to create a good neighborhood structure, this approach uses two powerful choice rules that emphasize the impact of candidate variables on the current solution with respect to their profit contribution. "Pseudo moves", similar to "aspirations", support these choice rules during the evaluation process. For the purpose of visiting as many relevant points as possible, strategic oscillation between feasible and infeasible solutions around the boundary is applied. To avoid redundant moves, short-term (tabu-lists), intemediate-term (cycle-detection), and long-term (recording frequency and significant solutions for diversfication) memories are used. Test results show that among the 45 generated problems (these problems pose significant or insurmountable challenges to exact methods) the approach produces the optimal solutions in 39 cases.lutions in 39 cases.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.13-27
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• 2012

Integer programming-based local search(IPbLS) is a kind of local search based on simple hill-climbing search and adopts integer programming for neighbor generation unlike general local search. According to an existing research [1], IPbLS is known as an effective method for the multidimensional knapsack problem(MKP) which has received wide attention in operations research and artificial intelligence area. However, the existing research has a shortcoming that it verified the superiority of IPbLS targeting only largest-scale problems among MKP test problems in the OR-Library. In this paper, I verify the superiority of IPbLS more objectively by applying it to other problems. In addition, unlike the existing IPbLS that combines simple hill-climbing search and integer programming, I propose methods combining other local search algorithms like hill-climbing search, tabu search, simulated annealing with integer programming. Through the experimental results, I confirmed that IPbLS shows comparable or better performance than the best known heuristic search also for mid or small-scale MKP test problems.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.257-263
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• 2003

방제는 재배작물에 발생하는 병충해를 최소화하여 농산물의 품질을 향상시키고 생산성을 증대시키는 중요한 관리 작업이며, 작물을 재배하는 동안에 여러 번 작업해야하며 노동 강도가 크고 농약중독 위험 때문에 농민이 기피하는 작업이다. 방제 방법에는 화학적 방제와 생물학적 방제, 농업적 방제, 기계적 방제 등 여러 방법이 있다. 화학적 방제는 잡초나 해충, 균의 밀도가 경제적 피해 수준 이하에서 유지되면서 더욱 확산되지 않도록 천연 또는 인공 화학물질을 이용하여 병해충이나 잡초를 억제는 방제방법으로 현재는 물론 가까운 미래에도 주를 이룰 것으로 예상된다. (중략)

• Management Science and Financial Engineering
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• v.8 no.2
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• pp.21-31
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• 2002

In this paper, we explore a new class of cutting planes by extending the concept of fractional S-K (S-K) cuts. This class of cuts is derived by applying a suitable surrogate constraint analysis that incorporates a special multiplier adjustment method to the generalized Gomory's fractional cut. We present computational results to provide insights into the performance of these cuts in comparison with other well known classes of cuts.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.243-246
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• 2004

배낭 문제는 단순한 것 같지만 조합형 특성을 가진 NP-hard 문제이다 이 문제를 해결하기 위해 기존에는 GA(Genetic algorithms)를 이용하였으나 지역해에 빠질 수 있어 잘못된 해를 찾거나 찾지 못하는 문제점을 갖고 있다. 본 논문에서는 이러한 문제점들을 해결하기 위해 막대한 병렬성과 저장능력을 가진 DNA 컴퓨팅 기법에 DNA에 기반한 변형된 GA인 DNA 코딩 방법을 적용한 ACO(Algorithm for Code Optmization)를 제안한다. ACO는 배낭 문제 중 (0,1)-배낭 문제에 적용하였고, 그 결과 기존의 GA를 이용한 것 보다 초기 문제 표현에서 우수한 적합도를 생성했으며, 빠른 시간내에 우수한 해를 찾을 수 있었다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.539-542
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• 2004

배낭 문제는 조합 최적화 문제로서, 다항 시간(polynomial time)에 풀리지 않는 NP-hard 문제이다 이 문제를 해결하기 위해 기존에는 DNA 컴퓨팅 기법과 GA 등을 사용하여 해결하였다. 하지만 기존의 방법들은 DNA의 정확한 특성을 고려하지 않아, 실제 실험과의 결과 차이가 발생하고 있다. 본 논문에서는 DNA 컴퓨팅 실험 과정에서 발생하는 DNA 조작 오류를 최소화하고, 보다 정확한 예측을 위해 함수 언어인 Haskell을 이용한 코드 최적화 DNA-Haskell을 제안한다. 코드 최적화 DNA-Haskell은 배낭 문제 중 (0,1)-배낭 문제에 적용하였고, 그 결과 기존의 DNA 컴퓨팅 방법보다 실험적 오류를 최소화하였으며, 또한 적합한 해를 빠른 시간 내에 찾을 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.13-22
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• 1997

In this paper, we supposed allocating the number of redundancies as the model of 0-1 knapsack problem and formulated the problem to maximize the systems reliability for a mission length. The formulated problem reduced the problem size using the modified branch and bound algorithm by Lagrangian relaxation. The subgradient method can optimize the set of solution. To verify the proposed method, we presented the improved resutls of the systems composed of two and ten component groups as the commparison of those in other papers.

• Review of KIISC
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• v.16 no.4
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• pp.15-24
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• 2006

Lenstra 등에 의하여 LLL 알고리즘이 처음 개발된 이래 최근까지 격자 이론은 공개키 암호의 분석 및 안전성 증명에 광범위하게 이용되어지고 있다. 초창기 Knapsack 계열 암호의 분석에 부분적으로 활용되었던 격자 이론은 1990년대에 인수분해, Diffie-Hellman, 격자 기반 공개키 암호로 그 분석 적용 분야가 확대되었고, RSA-OAEP를 비롯한 여러 암호 시스템들의 안전성 증명 등에도 중요한 도구로 활용되었다. 본 논문에서는 암호학의 도구로 활용되는 격자 이론의 개요를 살펴보고, 공개키 암호 분야의 분석에 있어 격자 이론이 활용된 사례들을 각 분야별로 결과 위주로 소개한다.