• School Mathematics
• /
• v.7 no.2
• /
• pp.123-137
• /
• 2005

Elementary combinatorial problem may be classified into three different combinatorial models(selection, distribution, partition). The main goal of this research is to determine the effect of type of combinatorial operation and implicit combinatorial model on problem difficulty. We also classified errors in the understanding combinatorial problem into error of order, repetition, permutation with repetition, confusing the type of object and cell, partition. The analysis of variance of answers from 339 students showed the influence of the implicit combinatorial model and types of combinatorial operations. As a result of clinical interviews, we particularly noticed that some students were not able to transfer the definition of combinatorial operation when changing the problem to a different combinatorial model. Moreover, we have analysed textbooks, and we have found that the exercises in these textbooks don't have various types of problems. Therefore when organizing the teaching , it is necessary to pose various types of problems and to emphasize the transition of combinatorial problem into the different models.

• Communications of Mathematical Education
• /
• v.20 no.3 s.27
• /
• pp.373-389
• /
• 2006

The purpose of this study is to compare the way of proving using combinational proof with the way of proving presented in the existing math textbook in the proof of combinational equation and to classify the problem-solving into some categories using combinational proof in combinational equation. Corresponding with these, this study suggests the application of combinational equation using combinational proof and the fundamental material to develop material for advanced study.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.6
• /
• pp.1550-1556
• /
• 1997

In this paper, we apply the evolutionary algorithm to the combinatorial optimization problem. Evolutionary algorithm useful for the optimization of the large space problem. This paper propose a method for the reuse of wastes of light water in atomic reactor system. These wastes contain several reusable elements, and they should be carefully selected and blended to satisfy requirements as an input material to the heavy water atomic reactor system. This problem belongs to an NP-hard like the 0/1 knapsack problem. Two evolutionary strategies are used as approximation algorithms in the highly constrained combinatorial optimization problem. One is the traditional strategy, using random operator with evaluation function, and the other is heuristic based search that uses the vector operator reducing between goal and current status. We also show the method which perform the feasible test and solution evaluation by using the vectored knowledge in problem domain. Finally, We compare the simulation results of using random operator and vector operator for such combinatorial optimization problems.

• Food Industry
• /
• s.150
• /
• pp.57-65
• /
• 1999

• Journal of Intelligence and Information Systems
• /
• v.3 no.2
• /
• pp.1-9
• /
• 1997

These papers propose an evolutionary algorithm for re-using output of waste fuel of light water reactor system in nuclear power plants. Evolutionary algorithm is useful for optimization of the large space problem. The wastes contain several re-useable elements, and they should be carefully selected and blended to satisfy requirements as input material to the heavy water nuclear reactor system. This problem belongs to a NP-hard like the 0/1 Knapsack problem. Two evolutionary strategies are used as a, pp.oximation algorithms in the highly constrained combinatorial optimization problem. One is the traditional strategy, using random operator with evaluation function, and the other is heuristic based search that uses the vector operator reducing between goal and current status. We also show the method, which performs the feasible teat and solution evaluation by using the vectorized data in problem. Finally, We compare the simulation results of using random operator and vector operator for such combinatorial optimization problems.

• Corrugated packaging logistics
• /
• no.56 s.12
• /
• pp.126-134
• /
• 2004

골판지 생산 공정에서 발생하는 문제와 이에 대한 해결책을 이 책 자체의 주제이다. 그래서 이 부분에서 충분히 이해할 수는 없지만 가장 많이 직면하는 문제점과 이러한 문제가 어떻게 발생하는지 그리고 이에 대한 진단 및 치료법 제안을 중심으로 설명하고자한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.761-764
• /
• 2013

Visiting k-combinations of a set S which has n elements is the general representation of many engineering problems. The performance of algorithms visiting all combinations, however, dramatically degrades with growing cases and the time to evaluate each combination. This paper presents the method to enhance the performance of these algorithms by a CUDA method. The experimental results show that the parallel algorithm running on GPU is approximately 900 times faster than the serial algorithm running on CPU.

• Journal of Agricultural Extension & Community Development
• /
• v.21 no.1
• /
• pp.1-34
• /
• 2014

In urban as well as rural areas, there is a vigorous movement to establish cooperatives which are based on the Framework Act On Cooperatives. Eight months after the enforcement of the law, more than 600 cooperatives reported their articles of association to the competent Mayor/Governor in rural areas. Considering the population distribution in urban and rural areas, this is not a small number. Though recently established rural cooperatives are acting throughout diverse business sectors, cooperatives in agricultural sector, which engage in agricultural production, processing and sales, occupy the largest portion of all the rural cooperatives. There are two types of juridical person that are allowed to engage in the agricultural production, processing and sales by the laws. They are Farm Association and Agricultural Business Corporation. Now in rural Korea, farmers tend to establish cooperatives by the Framwork Act On Cooperatives which are in the same business sector with Farm Association or Agricultural Business Corporation. There are many needs to improve legislation regarding cooperatives. Above all, the laws about Farm Association and Agricultural Business Corporation are in urgent need of improvement for the emerging rural cooperatives to be treated fairly.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10a
• /
• pp.61-63
• /
• 2003

지난 10년 동안 유전 알고리즘은 어렵고 복잡한 다양한 문제들을 해결하기 위한 새로운 방법으로 인식되어왔다. 이러한 유전 알고리즘의 성능은 알고리즘 내에 구현되는 여러 연산자들에 좌우된다. 따라서 많은 연구자들이 새로운 연산자 개발에 관심을 가져 왔었다. 특히, 가장 널리 알려진 조합최적화 문제 중에 하나인 알려진 traveling salesman problem (TSP)의 경우 NP-hard문제로 분류되어 현재까지 이를 해결하기 위한 다양한 유전 연산자들이 개발되어 왔었다. 따라서 본 논문에서는 TSP 문제를 test problem로 이용하여 이를 해결하기 위한 새로운 유전 연산자 특히 교차 (Crossover Operator) 연산자들을 제안하고 기존의 다양한 연산자들과 비교를 통해서 성능을 입증한다.

• Journal of the Korean School Mathematics Society
• /
• v.24 no.1
• /
• pp.19-38
• /
• 2021

The purpose of this study is to examine pre-service teachers' noticing when evaluating peers' mathematical problem posing tasks. To this end, 46 secondary pre-service teachers were asked to create real-world problems related to permutation and combination and randomly assigned to evaluate peers' problems. As a result, the pre-service teachers were most likely to notice the difficulty of their peers' mathematics problems. In particular, the pre-service teachers tended to notice particular conditions in order to increase the difficulty of a problem. In addition, the pre-service teachers noticed the clarity of a question and its solution, novelty of the problem, the natural connection between real-world contexts and mathematical concepts, and the convergence between mathematical concepts.