• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
• /
• pp.386-393
• /
• 2003

For fast Cholesky factorization, it is most important to reduce the number of non-zero elements by ordering methods. Minimum deficiency ordering produces less non-zero elements. However, since it is very slow. the minimum degree algorithm is widely used. To improve the computation time, Rothberg's AMF uses an approximate deficiency instead of computing the deficiency. In this paper we present simple efficient methods to obtain a good approximate deficiency using information related to cliques. Experimental results show that our proposed method produces better ordering quality than that of AMF.

• 전자공학회논문지S
• /
• 제34S권6호
• /
• pp.30-37
• /
• 1997

We present an efficient technique, bidirectioanl inertial maximum cost search technique, for th edetection and segmentation of circular shaped objects using the spatial information around the neighborhood of the boundary candidates. This technique searches boundary candidates using local pixdl information such as pixel value and its direction. And then to exclude pseudo-boundary caused by shadows or noises, the local contrast is defined between the clique of the boundary candidates and the cliques of the background. In order to effectively segment circular shaped boundary, the technique also uses the curvature based on trigonometirc function which determines circular shaped boundary segments. Since the proposed technique is applied to the pixel cliques instead of a pixel itself, it is proposed method can easily find out circular boundaries form iamges of the PCB containing circular shaped parts and the trees with round fruits compared to boundary detection by using the pixel information and the laplacian curvature.

• 대한수학회보
• /
• 제54권3호
• /
• pp.1037-1067
• /
• 2017

Motzkin and Straus established a close connection between the maximum clique problem and a solution (namely graph-Lagrangian) to the maximum value of a class of homogeneous quadratic multilinear functions over the standard simplex of the Euclidean space in 1965. This connection and its extensions were successfully employed in optimization to provide heuristics for the maximum clique problem in graphs. It is useful in practice if similar results hold for hypergraphs. In this paper, we develop a homogeneous multilinear function based on the structure of hypergraphs and their complement hypergraphs. Its maximum value generalizes the graph-Lagrangian. Specifically, we establish a connection between the clique number and the generalized graph-Lagrangian of 3-uniform graphs, which supports the conjecture posed in this paper.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
• /
• pp.273-273
• /
• 1996

• 대한수학회보
• /
• 제52권5호
• /
• pp.1423-1431
• /
• 2015

A clique-transversal set D of a graph G is a set of vertices of G such that D meets all cliques of G. The clique-transversal number is the minimum cardinality of a clique-transversal set in G. For every cubic graph with at most two bridges, we first show that it has a perfect matching which contains exactly one edge of each triangle of it; by the result, we determine the exact value of the clique-transversal number of line graph of it. Also, we present a sharp upper bound on the clique-transversal number of line graph of a cubic graph. Furthermore, we prove that the clique-transversal number of line graph of a triangle-free graph is at most the chromatic number of complement of the triangle-free graph.

• 대한수학회논문집
• /
• 제35권2호
• /
• pp.359-370
• /
• 2020

A graph G is called a well covered graph if every maximal independent set in G is maximum, and co-well covered graph if its complement is a well covered graph. We study some properties of a co-well covered graph and we characterize when the join, the corona product, and cartesian product are co-well covered graphs. Also we characterize when powers of trees and cycles are co-well covered graphs. The line graph of a graph which is co-well covered is also studied.

• Journal of Communications and Networks
• /
• 제16권4호
• /
• pp.421-429
• /
• 2014

We consider the problem of scheduling communications in wireless sensor networks (WSNs) to ensure battery preservation through the use of the sleeping mode of sensors.We propose a communication protocol for 1-hop WSNs and extend it to multi-hop WSNs through the use of a 1-hop clustering algorithm.We propose to schedule communications in each cluster in a virtual communication ring so as to avoid collisions. Since clusters are cliques, only one sensor can speak or listen in a cluster at a time, and all sensors need to speak in each of their clusters at least once to realize the communication protocol. We model this situation as a mathematical program.

• Journal of Information Processing Systems
• /
• 제15권5호
• /
• pp.1141-1155
• /
• 2019

Today, most approaches used in the recommendation system provide correct data prediction similar to the data that users need. The method that researchers are paying attention and apply as a model in the recommendation system is the communities' detection in the big social network. The outputted result of this approach is effective in improving the exactness. Therefore, in this paper, the personalized movie recommendation system that combines data mining for the k-clique method is proposed as the best exactness data to the users. The proposed approach was compared with the existing approaches like k-clique, collaborative filtering, and collaborative filtering using k-nearest neighbor. The outputted result guarantees that the proposed method gives significant exactness data compared to the existing approach. In the experiment, the MovieLens data were used as practice and test data.

• 한국인터넷방송통신학회논문지
• /
• 제15권1호
• /
• pp.269-276
• /
• 2015

본 논문은 지금까지 미해결 문제로 알려진 정점 색칠 문제에 대한 Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측을 증명하였다. Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측은 "k개의 $K_k$-클릭 합 교차 그래프는 k개의 색으로 칠할 수 있다". 즉, x(G)=k이다". Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측을 증명하기 위해 본 논문은 교차되는 정점수와 한 정점에서 교차되는 클릭수를 구하여 모두 짝수이면 그래프의 최소 차수 ${\delta}(G)$ 정점을 최대독립집합 (minimum Independent set, MIS)에 포함시키는 방법을 적용하고, 둘 중 어느 하나가 홀수이면 최대 차수 ${\Delta}(G)$ 정점을 MIS에 포함시키는 방법을 적용하였다. 알고리즘 수행결과 얻은 MIS 개수가 x(G)=k이다. $3{\leq}k{\leq}8$인 $K_k$-클릭 합 교차 그래프에 대해 실험한 결과 모든 그래프에서 x(G)=k를 얻는데 성공하였다. 결국, "k개의 $K_k$-클릭 합 교차 그래프는 k개의 색으로 칠할 수 있다".는 Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측은 성립함을 증명하였다.

• International Journal of Knowledge Content Development & Technology
• /
• 제7권4호
• /
• pp.5-26
• /
• 2017

A cross-cultural comparison of social networking structure on McDonald's Facebook fan sites between Taiwan and the USA was conducted utilizing the individualism/collectivism dimension proposed by Hofstede. Four network indicators are used to describe the network structure of McDonald's Facebook fan sites: size, density, clique and centralization. Individuals who post on both Facebook sites for the year of 2012 were considered as network participants for the purpose of the study. Due to the huge amount of data, only one thread of postings was sampled from each month of the year of 2012. The final data consists of 1002 postings written by 896 individuals and 5962 postings written by 5532 individuals from Taiwan and the USA respectively. The results indicated that the USA McDonald's Facebook fan network has more fans, while Taiwan's McDonald's Facebook fan network is more densely connected. Cliques did form among the overall multiplex and within the individual uniplex networks in two countries, yet no significant differences were found between them. All the fan networks in both countries are relatively centralized, mostly on the site operators.