• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1345-1357
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• 2017

A prototype selection method chooses a small set of training points from a whole set of class data. As the data size increases, the selected prototypes play a significant role in covering class regions and learning a discriminate rule. This paper discusses the methods for selecting prototypes in a classification framework. We formulate a prototype selection problem into a set covering optimization problem in which the sets are composed with distance metric and predefined classes. The formulation of our problem makes us draw attention only to prototypes per class, not considering the other class points. A training point becomes a prototype by checking the number of neighbors and whether it is preselected. In this setting, we propose a greedy algorithm which chooses the most relevant points for preserving the class dominant regions. The proposed method is simple to implement, does not have parameters to adapt, and achieves better or comparable results on both artificial and real-world problems.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.537-545
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• 2005

The aim of this paper is to solve the open problem on product properties of digital covering maps raised from [5]. Namely, let us consider the digital images $X_1 {\subset}Z^{n_{0}}$ with $k_0-adjacency$, $Y_1{\subset}Z^{n_{1}}$ with $k_3-adjacency$, $X_2{\subset}Z^{n_{2}}$ with $k_2-adjacency$ and $Y_2{\subset}Z^{n_{3}}$ with $k_3-adjacency$. Then the reasonable $k_4-adjacency$ of the product image $X_1{\times}X_2$ is determined by the $k_0-$ and $k_2-adjacency$ and the suitable k_5-adjacency$ is assumed on $Y_1{\times}Y_2$ via the $k_1-$ and $k_3-adjacency$ [3] such that each of the projection maps is a digitally continuous map, e.g., $p_1\;:\;X_1{\times}X_2{\rightarrow}X_1$ is a digitally ($k_4,\;k_1$)-continuous map and so on. Let us assume $h_1\;:\;X_1{\rightarrow}Y_1$ to be a digital $(k_0, k_1)$-covering map and $h_2\;:\;X_2{\rightarrow}Y_2$ to be a digital $(k_2,\;k_3)$-covering map. Then we show that the product map $h_1{\times}h_2\;:\;X_1{\times}X_2{\rightarrow}Y_1{\times}Y_2$ need not be a digital $(k_4,k_5)$-covering map.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.1
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• pp.109-115
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• 2000

In this paper, we propose a new method for power estimation in nodes of multi-level combinational circuits and describe its application to the extraction of common expressions for low power design. Extracting common expressions which is accomplished mostly by the extraction of kernels and common cubes, can be transformed to the problem of rectangle covering. We describe how the newly proposed estimation method can be applied to the rectangle covering problem and show the experimental results with comparisons to the results of SIS-1.2.

• Korean Management Science Review
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• v.26 no.3
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• pp.1-9
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• 2009

In this paper, we present mathematical models for the ring covering problems arising in the design of multi-ring WDM networks. Also, we present efficient algorithms to solve the suggested models. By the computational experiment, our model can solve the medium-sized networks efficiently and shows better performance than the existing heuristic method. Although we propose an efficient method for the column generation procedure, branching rule that does not destroy the column generation structure is unsolved. Further research is required to develop an effective branching rule.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.138-145
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• 2015

Heavy metal pollution in agricultural field near the abandoned metal mines is a critical problem in Korea. General remediation technique is to apply chemical amendments and soil covering. However, there is no specific guidelines for conducting soil covering. Therefore, main objective of this research was to determine optimum soil covering technique with microcosm experiment. Three different chemical amendments, lime stone (LS), steel slag (SS), and acid mine drainage sludge (AMDS), were examined and varied soil covering depth, 20, 30, 40cm, was applied to determine optimum remediation technique. Bioavailable heavy metal concentration in soil and total concentration of heavy metals in crop were monitored. Result showed that average heavy metal concentration in varied soil covering depth was ordered as 40 cm ($14.5mg\;kg^{-1}$) < 20 cm ($14.6mg\;kg^{-1}$) < 30 cm ($16.0mg\;kg^{-1}$) and also heavy metal concentration in crop was ordered as 40 cm ($100{\mu}g\;kg^{-1}$) < 30 cm ($183{\mu}g\;kg^{-1}$) < 20 cm ($190{\mu}g\;kg^{-1}$). In terms of chemical amendments, average heavy metal concentration was decreased as AMDS ($150{\mu}g\;kg^{-1}$) < SS ($151{\mu}g\;kg^{-1}$) < LS ($154{\mu}g\;kg^{-1}$). Overall, depth of soil covering should be over 30 cm to minimize bioaccumulation of heavy metals and SS and LS could be applied in heavy metal contaminated soil for remediation purposes.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.443-452
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• 2016

Current low-altitude radar system often fails to detect small unmanned aerial vehicles (UAV) because of their small radar cross section (RCS) compared with larger targets. As a potential alternative, a passive bistatic radar system has been considered. We study an optimal deployment problem for the passive bistatic radar system. We model this problem as a covering problem, and develop an integer programming model. The objective of the model is to maximize coverage of a passive bistatic radar system. Our model takes into account factors specific to a bistatic radar system, including bistatic RCS and transmitter-receiver pair coverage. Considering bistatic RCS instead of constant RCS is important because the slight difference of RCS value for small UAVs could significantly influence the detection probability. The paired radar coverage is defined by using the concept of gradual coverage and cooperative coverage to represent a realistic environment.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.1
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• pp.131-146
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• 1996

In this paper, we describe the facial structure of the steiner problem in a directed graph by formulating it as set covering problem. We first characterize trivial facets and derive a necessary condition for nontrival facets. We also introduce a class of valid inequalities with 0-1 coefficients and show when such inequalities define facets.

• KIEAE Journal
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• v.9 no.3
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• pp.29-36
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• 2009

Interior material covering as the final process of house-building, critically influences not only aesthetic character but also air quality of indoor space. Wall covering today, however, caused a serious social problem because of chemicals contained in the industrial wallpaper and artificial glue. In this context, Korean traditional wall covering of Han-ji can be an alternative model due to it's ecological character. Recently 'Hanok' attracts public attention, since society and people become to appreciate the unique beauty and value of our traditional culture. The values include natural beauty, emotional character, and environment-friendliness. Recognizing this, this paper intended to scrutinize the operating process of Han-ji as an interior finish material. Historical research method was employed, tracing the related articles in old literature and interviewing with the witness of the experienced expert. Thereby, healthier and unique aesthetic indoor environment can be expected to be sustainable along with the rich cultural life of ancestors.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.11a
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• pp.502-509
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• 2002

Maximal Covering 문제(MCP)란 행렬 상에서 n개의 열(column) 중 p개를 선택하여 m개의 행(row)중 최대한 많은 행을 cover하는 문제로 정의된다. 본 논문에서는 MCP를 유전 알고리즘(Genetic Algorithm)으로 해결하기 위해 문제에 적합하게 설계된 교차 연산자(crossover operator)와 비발현 유전인잔(unexpressed gene)를 가진 새로운 염색체 구조를 제시한다. 해결하고자 하는 대상 MCP의 규모가 매우 큰 경우 전통적인 임의교차(random crossover) 방법으로는 좋은 결과를 얻기가 힘들다. 따라서 본 연구에서는 그리디 교차(greedy crossover) 방법을 제시하여 문제를 해결한다. 그러나 이러한 그리디 교차를 사용하더라도 조기 수렴 등의 문제로 인해 타부 탐색 등의 이웃해 탐색 방법에 비해 그리 좋은 결과를 얻기가 힘들다. 본 논문은 이러한 조기 수렴 문제를 해결하고 다른 이웃에 탐색 방법보다 더 좋은 결과를 얻기 위해 비발현 유전인자(unexpressed gene)를 가진 염색체를 도입하여 해결함을 특징으로 한다. 비발현 유전인자는 교차 과정에서 자식 염색체의 유전인자로 전달되지 않은 정보 중 나중에라도 유용할 가능성이 보이는 정보를 보존하는 역할을 하여 조기 수렴 문제를 해결하는데 도움을 주어 보다 나은 결과를 얻을 수 있게 해준다. 대규모 MCP를 해결하는 실험에서 새로운 비발현 유전인자를 적용한 유전 알고리즘이 기존의 유전 알고리즘뿐만 아니라 다른 탐색 기법에 비해 더욱 좋은 성능을 보여줌을 확인하였다.

• Journal of the military operations research society of Korea
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• v.26 no.1
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• pp.34-46
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• 2000

The object of this study is to construct a model for an optimal allocation of short surface to air missile defending our targets most efficiently from hostile aircraft´s attack. For the purpose of this, we analyze and establish facility allocation concept of existing models, apply set covering theory appropriate to problem´s properties, present the process of calculating the probability of target being protected, apply Sherali-Kim´s branching variable selection strategy, and then construct the model. As constructed model apply the reducing problem with application, we confirm that we can apply the large scale, real problem.