• Journal of the Korea Society of Computer and Information
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• v.20 no.9
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• pp.21-29
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• 2015

The set partitioning problem is a well-known NP-hard combinatorial optimization problem, and it is formulated as an integer programming model. This paper proposes an Integer Programming-based Local Search for solving the set partitioning problem. The key point is to solve the set partitioning problem as the set covering problem. First, an initial solution is generated by a simple heuristic for the set covering problem, and then the solution is set as the current solution. Next, the following process is repeated. The original set covering problem is reduced based on the current solution, and the reduced problem is solved by Integer Programming which includes a specific element in the objective function to derive the solution for the set partitioning problem. Experimental results on a set of OR-Library instances show that the proposed algorithm outperforms pure integer programming as well as the existing heuristic algorithms both in solution quality and time.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.2
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• pp.120-126
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• 2005

Until now, the traditional production models and logistics have developed a broader strategic approach called supply chain. However, there are some obstacles to apply industry practice because of unrealistic assumptions. The most serious of them is that they assume the lead times are integer multiples of the planning time grid. This assumption makes it difficult to express the processing and transportation lags correctly. Thus, in this paper, we propose a new methodology for the integrated production/distribution model having non-integer time lags using the concept of dynamic production function. In case that the time lags are integer or non-integer, the dynamic production function reflects well the situation under given environments. Experiments show that the proposed model can express the real system more accurately than the prior model can.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.525-535
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• 1999

An optimal unit commitment model for efficient management of water and energy resources in a basin using combined mixed integer programming is developed. The combined mixed integer programming model is able to solve the inconsistency problem that may occur from mixed integer programming models. The technique which enables the use of conditional constraints and either-or constraints in the linear programming is also suggested. As a result of applying the combined mixed integer programming model to Lower Colorado River Basin in United States. the basin efficiency is decreased by 1.53% from the results of the mixed integer programming, while it is increased by 0.67% from the results of the historical operation. It is found that the decreased allowable error between power supplies and demands in the combined mixed integer programming causes the decreased basin efficiency.

• Journal of KIISE
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• v.43 no.6
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• pp.692-699
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• 2016

C compilers for 8-bit MCUs used in washing machines and refrigerators often do not follow the C standard to improve runtime performance. Developers who are unaware of the difference between C compilers following the C standard and the C compilers for 8-bit MCU can cause bugs that do not appear in the standard C environment but appear in the embedded systems using 8-bit MCUs. It is difficult for bug detectors that assume the standard C environment to detect such bugs. In this paper, we introduce integer promotion bugs caused by the different integer promotion rules of the C compilers for 8-bit MCU from the C standard and propose 5 bug patterns where the integer promotion bugs occur. We have developed an integer promotion bug detection tool and applied it to the washing machine control software developed by the LG electronics. The integer promotion bug detection tool successfully detected 27 integer promotion bugs in the washing machine control software.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1273-1278
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• 2012

In this paper, we introduce modified integer transforms for lossless image compression and evaluate their performances for two-dimensional transforms. The two-dimensional extensions of the modified integer transforms show different performances in terms of coding efficiency and computational complexity. Thus, we measure performances for two-dimensional separable transforms and a two-dimensional non-separable transform. The separable modified integer transform used in H.264, the modified integer transform using the lifting scheme, and the non-separable transform in JPEG XR are evaluated in this paper. Also, experiments and their results are given. The experimental results indicate that the modified integer transform using the lifting scheme shows the best performance in terms of compression efficiency.

• Management Science and Financial Engineering
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• v.14 no.2
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• pp.25-44
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• 2008

This paper concentrates on reduction of a Quadratic Fractional Integer Programming Problem (QFIP) to a 0-1 Mixed Linear Programming Problem (0-1 MLP). The solution technique is based on converting the integer variables to binary variables and then the resulting Quadratic Fractional 0-1 Programming Problem is linearized to a 0-1 Mixed Linear Programming problem. It is illustrated with the help of a numerical example and is solved using the LINDO software.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.349-353
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• 2008

Using the recently developed ABS algorithm for solving linear Diophantine equations we introduce an algorithm for solving a system of m linear integer inequalities in n variables, m $\leq$ n, with full rank coefficient matrix. We apply this result to solve linear integer programming problems with m $\leq$ n inequalities.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.2
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• pp.89-97
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• 2007

We study the maximum integer multiflow problem and the minimum multicut problem in a ring network. Both problems in a general network are known to be NP-hard. In this paper, we develop polynomial time algorithms to solve the problems. We also prove that even In a ring network, maximum multiflow is not always integral, which implies that the amount of maximum integer flow does not always reach the minimum capacity of multicut.

• Korean Journal of Mathematics
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• v.23 no.3
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• pp.327-336
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• 2015

In this paper, we study a constructive approximation by neural networks with positive integer weights. Like neural networks with real weights, we show that neural networks with positive integer weights can even approximate arbitrarily well for any continuous functions on compact subsets of $\mathbb{R}$. We give a numerical result to justify our theoretical result.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.652-654
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• 2002

정수 합동 분석(integer congruence analysis)은 프로그램 변수들의 의미 영역을 정수 합동(integer congruence) 집합으로 정의하여 분석한다. 정수 합동 분석을 위한 정수 합동 격자(lattice of integer congruences)와 순방향 요약 산술 연산자에 대한 정의는 이미 p. Granger에 의해 소개되었다. 하지만, 분석의 정확도에 영향을 미치는 역방향 요약 산술 연산자에 대한 연구는 아직 되어 있지 않다. 이 논문에서는 정수 합동 분석을 위한 역방향 요약 산술 연산자를 정의한다. 역방향 요약 산술 연산자를 정의하는 방법은 정수 방정식을 푸는 방법을 기반으로 고안되었다. 정의된 역방향 요약 산술 연산자는 프로그램 분석의 정확도를 높이는데 기여를 할 수 있는데, 이 논문에서는 예제를 통해서 이 사실을 보인다.