• Smart Structures and Systems
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• 제29권6호
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• pp.791-797
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• 2022

A complex system is comprised of numerous entities containing physical components, devices and hardware, events or phenomena, and subsystems, there are intricate interactions among these entities. To reasonably identify the critical fault propagation paths, a system fault propagation model is essential based on the system failure mechanism and failure data. To establish an appropriate mathematical model for the complex system, these entities and their complicated relations must be represented objectively and reasonably based on the structure. Taking a command and control system as an example, this paper proposes a hierarchical fault propagation analysis method, analyzes and determines the edge betweenness ranking model and the importance degree of each sub-system.

• 인터넷정보학회논문지
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• 제16권5호
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• pp.39-47
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• 2015

그래프에서 각 노드에 대해 그래프 내의 중요도를 나타내는 중심성(centrality)을 계산할 수 있고, 그 값에 따라 각 노드는 중요도 순위(ranking)를 갖는다. 중심성을 나타내는 방법으로는 여러 척도가 있는데, 본 연구에서는 연결도(degree) 중심성, 밀접도(closeness) 중심성, 특성벡터(eigenvector) 중심성, betweenness 중심성에 국한하여 연구를 수행하였다. 본 연구는 그래프에서 에지를 하나 추가할 경우, 그래프 내 노드 전체에 미치는 노드의 중심성 및 순위의 변화를 실험계산을 통해 확인한다. 그리고, 추가되는 에지가 노드 전체의 중심성 및 순위에 미치는 영향은 그래프의 형태에 따라 달라진다는 것을 PCA(Principal Component Analysis)를 통해 밝혔다. 이 사실은 그래프의 구조적 특성을 구분하는 방법으로도 사용될 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권2호
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• pp.540-557
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• 2021

Privacy vulnerability of social networks is one of the major concerns for social science research and business analysis. Most existing studies which mainly focus on un-weighted network graph, have designed various privacy models similar to k-anonymity to prevent data disclosure of vertex attributes or relationships, but they may be suffered from serious problems of huge information loss and significant modification of key properties of the network structure. Furthermore, there still lacks further considerations of privacy protection for important sensitive edges in weighted social networks. To address this problem, this paper proposes a privacy preserving method to protect sensitive weighted edges. Firstly, the sensitive edges are differentiated from weighted edges according to the edge betweenness centrality, which evaluates the importance of entities in social network. Then, the perturbation operations are used to preserve the privacy of weighted social network by adding some pseudo-edges or modifying specific edge weights, so that the bottleneck problem of information flow can be well resolved in key area of the social network. Experimental results show that the proposed method can not only effectively preserve the sensitive edges with lower computation cost, but also maintain the stability of the network structures. Further, the capability of defending against malicious attacks to important sensitive edges has been greatly improved.

• 디지털산업정보학회논문지
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• 제18권3호
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• pp.9-23
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• 2022

This study aims to examine research trends on the Internet of Things and smart city based on papers from the United States, Japan, and Korea. We collected 7113 papers related to the Internet of Things and smart city published from 2016 to 2021 in Elsevier's Scopus. Keyword frequency and centrality analysis were performed based on the abstracts of the collected papers. We found keywords with high frequency of appearance by calculating keyword frequency and identified central research keywords through the centrality analysis by country. As a result of the analysis, research on security, machine learning, and edge computing related to the Internet of Things and smart city were the most central and highly mediating research conducted in each country. As an implication, studies related to deep learning, cybersecurity, and edge computing in Korea have lower degree centrality and betweenness centrality compared to the United States and Japan. To solve the problem it is necessary to combine these studies with various fields. The future research direction is to analyze research trends on the Internet of Things and smart city in various regions such as Europe and China.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.616-631
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• 2019

With the rapid increase of information on the World Wide Web, finding useful information on the internet has become a major problem. The recommendation system helps users make decisions in complex data areas where the amount of data available is large. There are many methods that have been proposed in the recommender system. Collaborative filtering is a popular method widely used in the recommendation system. However, collaborative filtering methods still have some problems, namely cold-start problem. In this paper, we propose a movie recommendation system by using social network analysis and collaborative filtering to solve this problem associated with collaborative filtering methods. We applied personal propensity of users such as age, gender, and occupation to make relationship matrix between users, and the relationship matrix is applied to cluster user by using community detection based on edge betweenness centrality. Then the recommended system will suggest movies which were previously interested by users in the group to new users. We show shown that the proposed method is a very efficient method using mean absolute error.

• 디지털융복합연구
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• 제19권2호
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• pp.117-133
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• 2021

본 연구는 SNA(Social Network Analysis) 분석을 사용하여 부산항 연구동향을 파악하는 것을 목표로 했다. 연구분석 결과, Degree 중심성 측면에서는 Busan port(0.223)가 가장 높은 중심성을 가지고 있는 키워드로 나타났으며, DEA(0.060), AHP(0.056), Container terminal 그리고 Port competitiveness(0.049)순으로 나타났다. Betweenness 중심성 분석결과에서도 Busan port(0.245)가 가장 높은 키워드로 나타났으며, DEA(0.048), Container terminal(0.044), AHP(0.039), Busan new port(0.032)순으로 나타났다. 동향분석에서는 부산항이 세계 항만과 경쟁에서 우위를 점하기 위한 효율성 분석(DEA), 전략선택 및 경쟁분석(AHP) 등이 상위 중심성을 가진다는 시사점을 도출하였다. 하지만 현재 중요한 이슈로 부각중인 4차 산업과 관련된 연구는 부족한 실정이다. 향후 연구에서는 매스컴, SNS 등의 사회데이터를 병행 활용한 연구가 필요하다.

• 지능정보연구
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• 제15권4호
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• pp.159-182
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• 2009

본 연구에서는 기업에 이미 전산화되어 표준적인 형태로 존재하는 거래데이터를 이용하여 상품을 노드(node)로 놓고 동일 고객이 구매한 상품을 연결선(edge)으로 이은 상품 네트워크를 구성하였다. 사회 네트워크 분석에 널리 이용되는 중심성(Centrality)과 집중도(Centralization)를 구해서 고객의 구매패턴에서 중심이 되는 상품을 파악하였으며, 다른 상품들과 직간접적으로 연계되어 판매되는 상품관계의 총체적 흐름을 파악하고자 하였다. 또한성별, 연령별, 판매지역, 그리고 계절별 고객의 구매활동으로부터 도출되는 상품 네트워크에서 어떤 차이가 나타나는지 네트워크의 관점에서 밝히고자 하였다. 본 연구의 결과는 상품간의 구매관계 정보를 이용하여 교차판매, 상향판매, 그리고 추가판매 등을 보다 적극적으로 유도함으로써 기업의 매출증대와 더불어 판매상품의 다양성을 확보하기 위한 전략구축 방법과 평가 방법을 제시한다.

• 한국실내디자인학회논문집
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• 제16권6호
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• pp.144-151
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• 2007

The idea of shopping is changed from a purchase of merchandise to an experience of pleasure. This study is a space composition analysis for the introduction of theme in multi-plex shopping center design to reflect variable consumer trend and company marketing strategy, The study progressed through theoretical consideration and substance analysis about the shopping centers which had been designed by Jerd Partnership In Japan since 2000. The following is result. The path is a sole main street that is made of curve form, parallel and vertical circulating rout and movement of human being. It leads continuity. The node and landmarks have a circular court with typifier as powerful center, character of transition space and event for experience. It makes locational quality. The districts are composed of retail shops, restaurants and culture facilities and the edge is represented by closed vertical wall and parapet. It induces a domain. The characteristic of Jerde shopping center is an experience of theme environment through the path as betweenness with a story based on a main theme. It is mostly related nature or exotic element and is obviously represented at path and node. The node takes a round shape and bring about event as a court. The application of theme to the shopping center by Jerde has a significant meaning for place marketing.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2007년도 추계학술발표대회 논문집
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• pp.103-106
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• 2007

The idea of shopping is changed from a purchase of merchandise to an experience of pleasure. This study is a space composition analysis for the introduction of theme in multi-plex shopping center design to reflect variable consumer trend and company marketing strategy. The study progressed through theoretical consideration and substance analysis about the shopping centers which had been designed by Jerd Partnership from 2000 in Japan. The following is result. The path is a sole main street that is made of curve form, parallel and vertical circulating rout and movement of human being. It leads continuity. The node and landmarks have a circular court with typifier as powerful center, character of transition space and event for experience. It makes locational quality. The districts are composed of retail shops, restaurants and culture facilities and the edge is represented by closed vertical wall and parapet. It induces a domain. The characteristic of Jerde shopping center is an experience of theme environment through the path as betweenness space with a story based on a main theme.

• 전기학회논문지
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• 제66권12호
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• pp.1697-1704
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• 2017

As the power grid has been changed to a smart grid, existing power technologies are evolving into convergence technology through interdisciplinary research. According to the government policy to increase the proportion of renewable energy to 20% by 2030, the speed seems to be accelerating. This study analyzes the relationship between research technologies in order to grasp research trends of smart grid technology. To this end, we analyze the relationship between keywords extracted from topic modeling using social network analysis methodology. This is because, in the field where interdisciplinary research such as smart grid is active, each research topic is not independent, but research technologies emerging in one topic coexist in different topics, and linkage between research technologies can be important information. Therefore, this study can contribute to the analysis of research trend as it can be used as a package tool together with a topic modeling methodology.