• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.2923-2936
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• 2024

Modern risk management philosophy emphasizes the invulnerability of human beings to cope with all kinds of emergencies. The Nuclear Accidents Emergency Response Organization (NAERO) of Nuclear Power Plant (NPP) is the primary body responsible for nuclear accidents emergency response. The invulnerability of the organization to disturbance or attack from internal and external sources is crucial in the completion of its response missions, reduction of severity of accidents, and assurance of public and environmental safety. This paper focused on the NAERO of a certain NPP in China, and applied the complex network theory to construct the network model of the organization. The topological characteristics of the network were analyzed. Four importance evaluation indexes of network nodes including Degree Centrality (DC), Betweeness Centrality (BC), Closeness Centrality (CC) and Eigenvector Centrality (EC), along with Pearson coefficient correlation among the indexes were calculated and analyzed. Size of the Largest Connected Component (LCC) and Network Efficiency were used as measures regarding the invulnerability of the network. Simulation experiments were conducted to assess the invulnerability of network against various attack strategies. These experiments were conducted both in the absence of node protection measures and under protection measures with different node protection rates. This study evaluated the invulnerability of the NAERO network, and provided significant decision-making basis for the enhancement of the network's invulnerability.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.131-142
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• 2011

In recent years, Social Network Service, which is defined as a web-based service that allows an individual to construct a public or a semi-public profile within a bounded system, articulates a list of other users with whom they share connections, and traverses their list of connections. For example, Facebook and Twitter are the representative sites of Social Network Service, and these sites are the big issue in the world. A lot of people use Social Network Services to connect and maintain social relationship. Recently the users of Social Network Services have increased dramatically. Accordingly, many organizations become interested in Social Network Services as means of marketing, media, communication with their customers, and so on, because social network services can offer a variety of benefits to organizations such as companies and associations. In other words, organizations can use Social Network Services to respond rapidly to various user's behaviors because Social Network Services can make it possible to communicate between the users more easily and faster. And marketing cost of the Social Network Service is lower than that of existing tools such as broadcasts, news papers, and direct mails. In addition, Social network Services are growing in market place. So, the organizations such as companies and associations can acquire potential customers for the future. However, organizations uniformly communicate with users through Social Network Service without consideration of the characteristics of the networks although networks have different effects on information deliveries. For example, members' cohesion in an offline communication is higher than that in an online communication because the members of the offline communication are very close. that is, the network of the offline communication has a strong tie. Accordingly, information delivery is fast in the network of the offline communication. In this study, we compose two networks which have different characteristic of communication in Twitter. First network is constructed with data based on an offline communication such as friend, family, senior and junior in school. Second network is constructed with randomly selected data from users who want to associate with friends in online. Each network size is 250 people who divide with three groups. The first group is an ego which means a person in the center of the network. The second group is the ego's followers. The last group is composed of the ego's follower's followers. We compare the networks through social network analysis and follower's reaction analysis. We investigate density and centrality to analyze the characteristic of each network. And we analyze the follower's reactions such as replies and retweets to find differences of information delivery in each network. Our experiment results indicate that density and centrality of the offline communicationbased network are higher than those of the online-based network. Also the number of replies are larger than that of retweets in the offline communication-based network. On the other hand, the number of retweets are larger than that of replies in the online based network. We identified that the effect of information delivery in the offline communication-based network was different from those in the online communication-based network through experiments. So, you configure the appropriate network types considering the characteristics of the network if you want to use social network as an effective marketing tool.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.85-91
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• 2013

Recently, the weight of high-quality multimedia contents is explosively growing out of the network total traffic. This steep increase of media contents to require huge traffic does not contribute to the generation of revenue streams and it leads to the situation of dumb pipe to trouble network providers into the big burden of investment on the network expansion. Accordingly, the transfer to the smart network to enable the effective delivery of large-scale media is imminently challenging issue to the network providers to seek the profitable business. The smart network revolves around the technologies to enhance end-to-end quality and fair usage with network resources and to optimize the traffic for the contents delivery over the concept of Content-Centric Network. In this paper, we propose an architecture and fundamental functions suitable for the smart network and suggest improved test results through the construction of an experimental network.

• Journal of Information Management
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• v.36 no.4
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• pp.199-215
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• 2005

Experts participating in the knowledge expert network externalize their implicit knowledge by providing information or writing reports. Almost all the members of the network share externalized knowledge and the network facilitate the dissemination and diffusion of knowledge. Individuals reproduce another implicit knowledge by internalizing shared knowledge through the network and re-created knowledge is externalized, establishing knowledge circulation. In this paper, we analyze the expert groups of the Global Network of Korean Scientists & Engineers(KOSEN, www.kosen21.org), the Korea's No. 1 science and engineering knowledge expert community, with the application of the theory of policy network proposed by Marsh & Rhodes. According to the principal standards of policy network classification such as the number of participants, interaction among participants, consistency, distribution of resources and dependency, we categorize the KOSEN expert groups as closed policy network and opened issue network, and divide closed policy network into core community and periphery community.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.143-149
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• 2018

This paper focuses on how Singapore has adopted the 'Marriage Promotion Policy' for resolving the low birthrate and how it has been using the Social Development Network (SDN) to cope with the problem of low fertility. Social Development Network is an organization that shows Singapore's national stewardship to marriage, and has developed from the beginning to the social phenomenon of increasing number of highly educated women and decreasing fertility. The predecessor of Social Development Network is 'Social Development Unit' (SDU), absorbed the 'Social Development Service' (SDS) that was launched later, and reborn as Social Development Network in 2009. At its inception, Social Development Network has been recruiting and organizing its own memberships without the help of commercial marriage agencies, and since 2006 has been dedicated to delegating dating and matchmaking services to private companies and supporting projects. The purpose of this paper using literature analysis is to analyze the status and role of Social Development Network from the theoretical point of view of marital stewardship to the present, and to suggest meaningful implications for Korea which has the same social experience.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1063-1082
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• 2018

The concept of SDN (Software Defined Networking) endows the network with programmability and significantly improves the flexibility and extensibility of networks. Currently a plenty of research works on introducing SDN into wireless networks. Most of them focus on the innovation of the SDN based architectures but few consider how to realize the global perception of the network through the controller. In order to address this problem, a software defined carrier grade Wi-Fi framework called SWAN, is proposed firstly. Then based on the proposed SWAN architecture, a blueprint of introducing the traditional NSA (Network Situation Awareness) into SWAN is proposed and described in detail. Through perceiving various network data by a decentralized architecture and making comprehension and prediction on the perceived data, the proposed blueprint endows the controllers with the capability to aware of the current network situation and predict the near future situation. Meanwhile, the extensibility of the proposed blueprint makes it a universal solution for software defined wireless networks SDWNs rather than just for one case. Then we further research one typical use case of proposed NSA blueprint: network performance awareness (NPA). The subsequent comparison with other methods and result analysis not only well prove the effectiveness of proposed NPA but further provide a strong proof of the feasibility of proposed NSA blueprint.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.10
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• pp.877-888
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• 2012

Network virtualization technology is a crucial research issue of Future Internet which pursues a service-oriented architecture so-called NaaS (Network as a Service) or SDN (Software Defined Network). Network virtualization is expected to play an important role in Future Internet researches as a network testbed technology which enables innovative protocols to be experimented independently on a common testbed environment. We propose a control framework in order to provide user defined topology and bandwidth services with network virtualization and to separate and manage multiple-user traffics in a small and medium scale - single domain research network. The proposed framework (VIMS; Virtual network Integrated control and Management System) supports testbed expansions without any changes of heterogeneous virtual network support equipments through accommodation of each equipment's control plane. The framework shows a feasibility through applied to KOREN and we describe the differences and further study directions for improvement the framework comparing with GENI control framework.

• Health Policy and Management
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• v.16 no.4
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• pp.68-85
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• 2006

With the competitive environment accelerating in healthcare industry, the hospital network system is considered as one of the strategies for clinical and managerial efficiency. This study was intended to offer a theoretical view on the hospital network system and to analyze the current network status of hospitals in Korea. Specifically, network types were classified based on the criteria modified from previous studies, and were used to describe and compare the scope and intensity of associated activities. The questionnaire survey was conducted with 237 hospitals during the period of December 27 2005 to January 25 2006. Above 90% of tertiary and secondary care hospitals were under the network system, while only 20% of primary care clinics were affiliated. In general, the scope and intensity of network activities was limited. Vertical and/or clinical integration was more common than horizontal and/or managerial integration. Three most frequent types of hospital network systems were clinical-vertical integration (Type A), clinical/managerial-vertical integration(Type B), and clinical/managerial-horizontal /vertical integration (Type C). Such network types differentiated significantly different features of affiliated hospitals and network systems. The affiliation duration to the network system was the only significant factor influencing on the network type. The strategic approach to the network system was emphasized for hospitals to increase the potential advantage of hospital network systems.

• Journal of the Korea Society of Computer and Information
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• v.17 no.3
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• pp.85-93
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• 2012

In this paper, I designed the satellite system, using the MF-TDMA (Multi Frequency-Time Division Multiple Access) DAMA (Demand-Assigned Multiple Access) method, that allocates the satellite resources more effectively to prevent a large quantity data discard when Earth Terminals (ETs) request their satellite network resource to Network Controller (NC) by using their history information, such as traffic pattern or traffic class which have been receiving, and the network controller allocates the satellite network resource and send to earth terminals by using his history information that earth terminals have been requested already. The U.S. Military Warfighter Information Network-Tactical (WIN-T) community has selected the L-3 Linkabit MF-TDMA DAMA Network Centric Waveform (NCW) as the networking standard for full-mesh IP over SHF satellite communications. In the MF-TDMA DAMA satellite network, network controller allocates the satellite network resources and enables maximum 255 earth terminals to communicate each other for periodic satellite network resource requests of earth terminals.

• The KIPS Transactions:PartC
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• v.19C no.2
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• pp.149-152
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• 2012

In the roaming case, the cost of using the visited network is larger than that of home network. So, if a mobile terminal is connected to the visited network, even though it actually came back to the home network, the user may unduly pay for communication. Such a problem frequently occurs when many networks are overlapped in the same region, as shown in the case of Poland. In this paper, we propose a network search algorithm to support the fast comeback to home network in the roaming environment. In the proposed scheme, which is based on the 3GPP specification, the mobile terminal tries to search the home network by using a database of network information, as fast as possible. For performance evaluation, we construct a virtual testbed with real terminal and network equipment to emulate the service providers in Poland. From the experimental results, we can see that the proposed scheme can reduce the time of comeback to the home network by 3~60 minutes, compared the existing 3GPP scheme.