• Journal of The Korean Association For Science Education
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• v.36 no.5
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• pp.791-800
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• 2016

This research aimed to identify core words used as associative words and definitions for expressing 'electricity' terminology and to find how core ones are activated to form a cognitive structure, using network analysis. The participants targeted 83 university freshmen students in the University of Education located in suburbs. Depending on their gender, whether or not they completed physics in high school, the associative words and definitions were analyzed using the network method, classifying two sections: before-lesson and after-lesson. The result is as follows: At before-lesson associative words for 'electricity' terminology, a slightly different network construction was revealed based on their two properties. However, after the class, they showed similar network structure irrespective of their distinctive characteristics. When it comes to other 'electricity' definitions, before taking the course, they had similar network connection across the gender but based on physics education status, there appeared subtle differences. Ultimately, after the class they demonstrated similar network structure regardless of their features. In conclusion, this paper suggests educational implications on network analysis, which covers 'electricity' terminology of university students.

• Journal of the Korean Geographical Society
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• v.44 no.2
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• pp.187-205
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• 2009

Failures on network components of a public transportation system can give rise to the severe degradation of entire system functionality. This paper aims at exploring how potential failures can affect the system flows and reliability of subway network systems in Metropolitan Seoul. To evaluate the range of impacts of disruptions, this research employs a probabilistic approach, network reliability. Network reliability measures the network resiliency and probability of flow loss under a variety of simulated disruptions of critical network components, transfer stations in subway system. By identifying the best and worst scenarios associated with geographical impact, as well as evaluating the criticality of transfer stations, this research presents some insights for protecting current subways systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.479-482
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• 2011

This paper proposes a design of a ship backbone network-based on the survival and efficiency of the ship network. Currently IEC operates the standard ship network, a standard specification "IEC 61162-410 maintains the operation of the network. IEC 61162-410 offers a high stability of the ship network by using terminal equipment. But current studies are incomplete because it has been assumed that the ship's network will operate at double its current capacity. This paper analyzes the double ship backbone topology for an organization and then will summarise the minimum costs required to implement the ship backbone topology using an ILP. Also, we present an effective traffic assignment technique that uses an ILP, metaheuristic, heuristic algorism-based underlying the ship backbone network. The results by experimenting the design of the network confirmed a greter efficiency, stability and cost-effectiveness of the ship network.

• Journal of the Korean Society for information Management
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• v.27 no.2
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• pp.61-74
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• 2010

The knowledge sharing in a knowledge management process is much affecting generation and distribution of knowledge. Especially, the knowledge distribution is being revitalized with the center of social media service like twitter and library service 2.0 in the knowledge-based IT (Information Technology) environment. The present research analyzed the structure and characteristics of a social network inside an organization that is growing like an organism through self-organization through tools for SNA (Social Network Analysis) and multiple regression analysis of independent variables such as 1) a relationship between social network's structure and knowledge sharing, 2) a relationship between structural holes and knowledge sharing influence of centrality, 3) a relationship between individual ability and knowledge sharing of information technology and work recognition.

• Korean Journal of Legislative Studies
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• v.24 no.2
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• pp.67-99
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• 2018

This study analyzes the revision bills of the National Assembly Law in the 19th National Assembly in which the National Assembly Advancement Act was enacted, with the question "who are involved in the revision of the procedural rules, and what motivates them?" The cosponsor network analysis focusing on primary sponsors of the revision bills shows that the network was constructed by party affiliations. A small number of members with high degree centrality attempted to cooperate with each other at the cosponsoring stage, but the legislation did not pass through the related committee. In addition, this study tests the four competitive hypotheses (the committee hypothesis, the distributive politics hypothesis, the ideological distance hypothesis, and the partisan affiliation hypothesis) about the motivation to propose amendments by using the regression models which include newly measured variables. Only the committee hypothesis and the partisan affiliation hypothesis are empirically supported. This implies that partisan consideration is still significant in amending the National Assembly Law even after the National Assembly Advancement Act, and thus party leaders' willingness to seek bipartisan compromises is at the heart of problem-solving.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1416-1427
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• 2012

This paper proposes a design technique of a survivable ship backbone network, which describes a near optimal configuration scheme of physical and logical topologies of which the survivable ship backbone network consists. We first analyze and present an efficient architecture of a survivable ship backbone network consisting of redundant links and ship devices with dual communication interfaces. Then, we present an integer linear programming-based configuration scheme of a physical topology with regard to the proposed ship backbone network architecture. Finally, we present a metaheuristic-based configuration scheme of a logical topology, underlying the physical topology.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.205-218
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• 2012

Mobility management of the mobile nodes and provision of seamless handover is crucial to an efficient support for the global roaming of the mobile nodes in next-generation wireless networks. Mobile IPv6 and mobility management in extended IP layer, which highly depend on traffic characteristics and user mobility models, were proposed by the IETF. Therefore, to evaluate the in-depth performance about these factors is important. Generally, the performance of IPv6-based mobility management protocol is evaluated through simulation. This paper shows the correlation between network parameters and performance metrics through numerical results, which is investigated how influence handoff latency and packet loss. And this paper uses mathematical analysis of the system parameters, such as the subnet residence time, the packet arrival rate and delay in wireless connection through the analytical framework which evaluate the performance of IPv6-based mobility management protocol.

• Journal of Internet Computing and Services
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• v.16 no.6
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• pp.1-9
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• 2015

In this paper, we study the coexistence of typical radio access technologies (WiMAX, CDMA, WLAN) in heterogeneous networks. Although the radio accesses employ different frequency band, they can interfere with each other due to out-of- band emission. We compute the minimum adjacent channel interference ratio (ACIR) to satisfy the allowable level of interference, and the resulting minimum frequency separation (guard band) between interfering and victim system. We observe that WiMAX-WLAN coexistence and WiMAX-CDMA coexistence are feasible with at least 20 MHz and 15 MHz guard bands, respectively.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.711-718
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• 2004

Packet sampling is the techniques to collect a part of the packets through network and analyze the characteristicsof the traffic for managing the network and keeping security. This paper presents a study on the sampling techniques applied to DDoS traffic and on the characteristics of the sampled traffic to detect DDoS attack efficiently and improve traffic analysis capacity. Three famous sampling techniques are evaluated with different sampling rates on various DDoS traffics. To analyze traffic characteristics, one of the DDoS attack detection method. Traffic Rate Analysis (TRA) is used. Simulation results verify that using sampling techniques preserve the traffic characteristics of DDoS and do not significantly reduce the detection accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.190-192
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• 2012

최근 소셜 네트워크 서비스는 언제 어디서나 정보를 누구라도 손쉽게 전달하고 볼 수 있는 수단으로 각광받고 있다. 소셜 네트워크 서비스의 주요한 특징은 사람과 사람, 사람과 정보, 정보와 정보 간의 관계 네트워크로서, 사용자가 능동적으로 참여한다는 것이다. 하지만 범람하는 수많은 정보들 속에서 사용자가 직접 정보를 검색 및 분류해야 하는 과정은 사람과 정보간의 관계 네트워크 측면에서 소셜의 의미를 충족하지 못한다. 이러한 기존의 정보 활용법은 사용자의 선호도에 따른 맞춤형 정보의 수용과 공유를 제시하지 못하고 있다. 본 연구에서 설계된 사용자 맞춤형 서비스 시스템은 사용자의 상황인식 속성정보와 이에 따른 선호도를 평가하는 알고리즘을 기반으로 하여 보다 효율적인 커뮤니티 공간이 제공될 수 있는 맞춤형 커뮤니티 서비스 시스템을 설계 제안한다. 제안된 시스템에서는 소셜 네트워크 서비스에서 사용자가 텍스트를 읽거나 작성하는 행위를 바탕으로 사용자의 관심사를 제공된 알고리즘으로 분석하여 사용자의 선호도에 따른 정보를 분류하고, 사용자의 인적정보로부터 선별한 유사 사용자들을 통해 신뢰성이 높은 정보를 우선적으로 선출한다. 따라서 사용자의 속성과 선호도를 고려한 상황인식 정보를 제공함으로써 사용자가 직접 정보를 검색 및 분류하는 과정을 단축하고 정보의 신뢰성을 향상할 수 있는 방법을 제시한다. 이러한 상황인식 기반의 맞춤형 커뮤니티 서비스 시스템은 실시간으로 많은 정보가 공유되는 서비스에서 다양하게 적용되어 인터넷 신문, 타겟 마케팅 광고 등의 응용분야에서 다양한 정보제공 서비스 시스템으로 적용될 수 있을 것으로 본다.