• Journal of Korea Port Economic Association
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• v.32 no.1
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• pp.17-28
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• 2016

This study examines the cruise course network structure in the Asian regions and the centrality of ports using social network analysis (SNA). For network analysis of Asian cruise courses, a data network of cruise courses was constructed using data on courses of cruise ships operating in Asian ports collected from the reports of the Cruise Lines International Associations.There are 249 nodes or ports of ship companies that provide cruise courses to Asia between from October 2015 to June 2016, and these nodes connect 545 ports. Density analysis based on ports where cruise ship companies operated cruise ships showed that, from October 2015 to June 2016, the density was 0.009, which was lower than the average of global port network density (2006 to 2011) and railroad network density. In addition, was calculated to be, which means that connection with all ports was possible through 2,180 steps. In the analysis of the Asian cruise course network centrality, Singapore ranked first in both out-degree and in-degree in connection centrality, followed by Hong Kong, Shanghai, Ho Chi Minh, and Keelung. Singapore also ranked first in the result betweenness centrality analysis, followed by Penang, Dubai, and Hong Kong. From October 2015 to June 2016, the port with the highest Eigenvector centrality was Hong Kong, followed by Ho Chi Minh, Singapore, Shanghai, and Danang. In the case of the domestic ports Incheon, Busan, and Jeju, connection centrality, betweenness centrality, and Eigenvector centrality all ranked lower than their competitor Chinese ports.

• Journal of Korea Port Economic Association
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• v.32 no.1
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• pp.79-95
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• 2016

This study identifies themes and trends in maritime economics and logistics by examining 303 papers published in international journals from 2000 to 2014 using keyword network analysis. Network analysis can be used because the collected data follow Zipf's law and the power law. Utilizing the degree centrality and betweenness centrality, we find the important keywords in each five year period and determine the importance of shared keywords. To further explain keyword centralities, we invented a Delta-C algorithm to show the trends of keywords over time. We found that degree centrality is useful for identifying important research themes in each period because it is mainly concerned with the number of connections. On the other hands, betweenness centrality is useful to determine the unique themes that emerge in each of the specific periods.

• Journal of the Korean Society for Library and Information Science
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• v.48 no.2
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• pp.353-378
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• 2014

The purpose of this study is to find factors to affect on the formation of semantic relation from terminology and what is to be affected by these factors to build the database scheme of terminology dictionary by a structural definition. In this research, 826,905 keywords of 88,874 social science articles and 985,580 keywords of 125,046 humanities science articles in the KCI journals from 2007 to 2011 were collected. From collected data, subject complexity, structural hole, term frequency, occurrence pattern and an effect between the number of nodes and the number of patterns which were derived from the semantic relation of linked terms of established 'STNet' System were analyzed. The summarized results from analyzed data and network patterns are as follows. Betweenness Centrality, term frequency, and effective size affect the numbers of semantic relation node. Among these factors, betweenness centrality was the most effective and effective size. But term frequency was the least effective. Betweenness Centrality, term frequency, and effective size affect the numbers of semantic relation type. Term frequency is the most effective. Therefore, when building a terminology dictionary, factors of betweenness centrality, term frequency, effective size, and complexity of subject are needed to select term. As a result, these factors can be expected to improve the quality of terminology dictionary.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.1011-1022
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• 2006

WSN(Wireless Sensor Network) performs to detect and collect environmental information for one purpose. The WSN is composed of a sink node and several sensor nodes and has a constraint in an aspect of energy consumption caused by limited battery resource. So many required mechanisms in WSN should consider the remaining energy condition. To deploy WSN, tile collected information is required to protect from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. we propose asynchronized key management considering energy efficiency over WSN. The proposed key management is focused on independence and difference of the keys used to deliver the information over several routes over the network, so disclosure of any key does not results in exposure of total key information over the overall WSN. Also, we use hash function to update key information for energy efficiency Periodically. We define the insecurity for requested security Properties and Proof that the security properties are guaranteed. Also, we evaluate and analyze the energy efficiency for the proposed mechanism.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.2
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• pp.39-47
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• 2010

In Wireless Sensor Network, transmission errors are frequently occurred due to the node failure, battery discharge, and interference by objects. Although Directed Diffusion has been considered as a prominent Data-centric routing algorithm, it revealed some weaknesses at this kind of unexpected network errors. In order to address the problem, we proposed a radio-aware routing algorithm for improving reliability of Directed Diffusion in Wireless Sensor Networks. The proposed algorithm is aware of the network status based on the radio information of MAC and PHY layers using a cross-layer approach. The link quality and the node failure information from the acquired network status were used to decide an alternative path to provide a reliable data transmission in error-prone sensor networks. The proposed algorithm showed its effectiveness of the data delivery rate and data ratio with several simulations consisting of various error rates and the number of nodes.

• Smart Media Journal
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• v.9 no.1
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• pp.9-15
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• 2020

Recently there have been increasing attempts to apply blockchains to businesses and public institutions. Blockchain is a distributed shared ledger with excellent transparency and security of data and through consensus algorithm, the same data can be shared to all nodes in order. In this paper, Modified PBFT which does not modify the PBFT consensus algorithm is proposed. MPBFT is able to tolerate Byzantine faults on a private blockchain on an asynchronous network. Even with the increase of participating nodes, the network communication cost can be effectively maintained. Modified PBFT takes into account the characteristics of an asynchronous network environment where node-to-node trust is guaranteed. In response to the client's request, PBFT performed the entire participation broadcast several times, but Modified PBFT enabled consensus and authentication through the 2 / N leader. By applying the Modified PBFT consensus algorithm, the broadcast process can be simplified to maintain the minimum number of nodes for consensus and to efficiently manage network communication costs.

• Journal of Technology Innovation
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• v.29 no.1
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• pp.39-73
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• 2021

The cooperative network structure influences the academic performance of the research institute. In particular, South Korea's Government-Funded Research Institutes(GRI) need to establish an efficient cooperative system as a leading national R&D implementer. This study applied the Small World structure, which has been discussed as an efficient network structure, and the centrality of representing the characteristics of nodes to the cooperative network of GRI in Korea. Based on the SCIE published data from 2010 to 2019, we analyze how the Small World characteristics and centrality of GRI contribute to academic performance using a network analysis and Feasible GLS regression. The GRI cooperative network has shown that the Small World network structure facilitates the academic performance. In addition, centrality indicating the degree of direct connection showed positive significance, but centrality indicating the degree of intermediary was not significant or negative. The results of this study explain that the higher the number of institutions that exchange and cooperate, the higher the academic performance, and the higher the performance of the institutions that serve as the center of cooperation. In addition, it was established that the stronger the cooperative network of GRIs have the characteristics of Small World, the more effective it is to create research results. This study applies centrality and Small World previously discussed as an efficient network structure to the GRI cooperation network and provide implications for establishing policies and strategies related to R&D cooperation among GRIs.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.429-433
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• 2003

웹상의 문서는 데이터 중심의 표준 언어인 XML 문서로 표현된다. XML 데이터를 범용적이고 우수한 성능의 관계형 데이터베이스와 연동하여 이용하기 위해서는 두 구조 사이의 맵핑 과정이 필요하다. 계층적 구조의 XML 문서와 데이터베이스의 평면적인 구조의 차이를 고려한 구조 맵핑을 위해서 검색 시스템에 적합한 가상분할 방식으로 엘리먼트를 분석하여 관계 스키마를 정의한 후 XML 문서를 저장한다. 이를 위해 스키마는 DTD 에 독립적인 형태로 변환하고, 엘리먼트의 추가와 삭제, 검색의 효율성을 위해 노드간의 위치 정보와 함께 독립적인 ID를 부여하여 구조적 검색을 수행할 수 있게 하였다.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.23-30
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• 2018

The purpose of this research was to introduce network analysis method for analyzing pesticide residues in incongruity commercial agricultural commodities. Based on the "results in pesticide residues on incongruity commercial agricultural commodities" on "Guidelines for food safety management 2017", we used centrality analysis for pesticide residues via degree, closeness and betweenness centrality measurement. In case of degree centrality result, chlorpyrifos and diazinon were the most highly "connected node" in pesticide network. For the closeness centrality result, the most pesticides showed the similar closeness trend except for 19 species of pesticides. Fludioxonil and chlorpyrifos are recognized as the "bridge" of pesticides network with their high betweenness centrality. The results of network analysis show the "relation" data, which could not represent through out the conventional statistical analysis, among the pesticide residues. We hope that the network analysis method will be appropriate and precise tool for analyzing pesticide residues via elaboration and optimization.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.179-186
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• 2020

The purposes of this paper were: 1) to identify the structural changes of the northeast Asia airport network caused by the pandemic of COVID-19 using social network analysis (SNA) and 2) to suggest proposals for improving airport competitiveness. In this respect, the entire international air routes in northeast Asia airport collected data of 4-10 March 2019 and 9-15 March 2020 through schedules analyzer database of OAG. We found that both the density and centrality have decreased since the spread of COVID-19. The government and airport authorities need active support such as a reduction of various fees and a moratorium on transportation rights to overcome the crisis in the air transport industry. When the COVID-19 situation calms down in the future, we hope that further research will be conducted to identify the structural changes in the SNA aspects through the vast data establishment in countries such as the EU and America.