• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.9-22
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• 2006

When the legacy multicast routing protocols are adopted in If-based mobile core networks, there are some problems such as traffic injection from unnecessary sources, traffic overhead by group management and router performance degradation by large amount of multicast session information. In this paper, we propose a stateless multicast mechanism which has no need to maintain multicast information for session status and reduces redundant network overhead for maintaining multicast tree. In addition interworking with IGMPv3 gets rid of traffic from unnecessary sources which have no registration from receivers. The operations of essential components including a gateway node for interworking with the legacy Internet multicast network, a gateway node for transparency to radio access network and a intermediate node in mobile core networks, are definitely defined and the proposed communication architecture is completed. Finally we evaluate and approve the performance of the proposed architecture by means of well-designed network simulation.

• Journal of Internet Computing and Services
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• v.4 no.3
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• pp.47-55
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• 2003

Multicast protocols ore developed in order to support group communications efficiently, However. there still exist some issues to be solved for deploy multicast protocol in the public internet. This paper refers problem of existing Reliable Multicast Protocols and redesigns component function, and proposes enhanced reliable multicast transport protocol, This paper proposed a improved multicast transport scheme in NACK based reliable multicast. This scheme is much faster than by sender-initiated or receiver-initiated recovery and latency is smaller. Designed components are implemented in UNIX environment using C programming longuage. Then the protocol was evaluated performance through simulation. As the result, proposed protocol is better than existing protocols in both of transmission delay and packet loss. Especially, proposed protocol in this paper con be used in multicast services needed high reliability.

• Korean journal of communication and information
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• v.19
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• pp.213-238
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• 2002

Ie is popular belief among the authorities concerned and their apologists that media coverage of terrorism promotes terrorism and is used as publicity by terrorists. Generally speaking, however, in reporting terrorism, the media become not terrorists' but state's means of publicity, and condemn terrorism, while rationalizing state's violence against terrorism. Terrorists may be successful in attracting public attention at the initial stage of terrorism, but usually fail in publicizing their cause. This fact notwithstanding, the authorities concerned and their apologists maintain thar media coverage of terrorism should be controlled, because it works as publicity for terrorists. Now it can be said that there is an intention to control the media when it is asserted that media coverage of terrorism works as publicity for terrorists. To present these arguments, this article discusses the news values and publicity aspect of terrorism, reviews some problems of and misunderstanding about media coverage of terrorism, and for illustrations, look into the American media's coverage of the 9-11 terrorism against the U. S. and "war on terror". that is, state terrorism taken as a countermeasure to it by the U. S.

• Journal of The Korean Association of Information Education
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• v.5 no.1
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• pp.119-129
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• 2001

The present school is faced with the crisis of school collapse and classroom collapse under a bureaucratic and authoritative atmosphere. The method to respect individual opinions and to discuss with open mind is needed. The study is to establish the system of SDR and to make it possible to express the wholesome and various ideas of members by using it. SDR is related with the interruption DB to stop up unsound messages. The result of this study shows that SDR is very helpful to make a culture of discussion in a school in the respect of enlarged chances for teachers and students to participate, active and open participation, changing of attitude in achieving group goal and formation of desirable culture of discussion.

• Journal of The Korean Association of Information Education
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• v.24 no.4
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• pp.291-300
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• 2020

Although the need for international online courses and the number of online learners has been rapidly increasing, the online class evaluation has been mostly relying on the quantitative survey analysis. So a more objective evaluation method has to be developed to more accurately assess online course satisfaction. This study highlights the benefits of using big data analysis from the bulletin board messages of online learning system as a method to evaluate the online courses. In fact, automatic classification technology is recognized as an important technology among big data analysis techniques. Our team applied this technique to evaluate the online courses. From the delphi analysis results, suggested method was concluded that the evaluation items and classification results are suitable for online course evaluation and applicable in schools or institutions. This study has confirmed that the rapidly accumulating big data analysis technology can be successfully applied to the education sector with the least change. It also diagnosed a meaningful possibility to expand the big data analysis for further application.

• Journal of Internet Computing and Services
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• v.11 no.3
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• pp.65-74
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• 2010

In the ubiquitous healthcare, automated diagnosis is commonly achieved by an agent system to provide intelligent decision support and fast diagnosis result. Mobile agent technology is used for efficient load distribution by migrating processes to a less loaded node which is considered in our design of a ubiquitous healthcare system. This paper presents a framework for ubiquitous healthcare technologies which mainly focuses on mobile agents that serve the on-demand processes of an automated diagnosis support system. Considering the efficient utilization of resources, a balanced clustering for the load distribution of processes within nodes is proposed. The proposed algorithm selects overloaded nodes to migrate processes to near nodes until the load variance of the system is minimized. Our proposed balanced clustering efficiently distributes processes to all nodes considering message overheads by performing the migration to the near nodes.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.10-19
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• 2005

It may not be strange to anticipate that the forth-coming epoch of electronic government would bring us lots of convenience on account of ubiquitous environment with mobile devices. Such environment enables us to access the up-to-date information anytime and also a worker to carry out administration services to perform one's line of duty at anytime with electronic, handy devices such as PDA. What we now recognize from the field of electronic traffic administration services is that the office work flow as well as the public services has been remarkably improved by using of not only text but video and image information under the distributed, mobile environment. One of key requirements of this kinds of services is the feature of exchanging various information among multiple information publishers and subscribers. We call this feature Messaging Services generally The study in this paper focuses on the architecture design of the Messaging Engine software, complying with the pattern-oriented software architecture design methodology. And our contribution also goes to the discovery of three architecture patterns found in the design process and the efficient multi-threading architecture compared to one of the Messaging Engine solutions.

• The Journal of Society for e-Business Studies
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• v.9 no.1
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• pp.39-59
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• 2004

E-business automates overall activities in a company and allows distributed systems to communicate their information. The automation and information sharing improves its productivity and responsiveness. B2B workflow systems progress their business processes electronically and help the companies to monitor their execution and administrate the processes. This research analyzes the technologies and standards for B2B workflow integration, and proposes three approaches to implement effectively workflow integration. We analyze several existing workflow standards and business process definition languages, and compare their structures and features. And we examine the messaging technologies and architectures to implement business integration. Finally we extract a reference model for B2B workflow integration, and propose three types of workflow integration and implementation designs. This research helps companies to understand the workflow standards and the messaging technologies for B2B workflow integration, and to implement workflow integration systems that are suitable for their e-business environments.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.679-686
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• 2005

Because EPON access network shares a medium and aggregates the traffic from EPON subscribers, scheduling media access control on EPON bandwidth allocation is very important. Furthermore DBA mechanism of EPON based on TDMA is out of specification and up to implementation. This paper deals with a DBA method to guarantee the QoS of the delay sensitive traffic on the base of best-effort service and delay priority queue management. The proposed method performs virtual scheduling algorithm for the integrated traffic. It uses the same MAC messages and tries to guarantee the QoS of higher priority traffic first with a simple DBA architecture. We evaluate the algorithm for traffic delay according to polling interval and traffic load of upstream and downstream. The results show that the proposed method can guarantee the QoS of the delay sensitive traffic with priority of the service classes.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.617-622
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• 2005

Lately, the MANET research has focused on providing routing services with security and previous schemes have been proposed for detecting malicious nodes in a MANET. However, they still include some problems which malicious nodes cannot be found when they falsely report other nodes as malicious. Accordingly, we propose a novel and efficient scheme for detecting malicious nodes using report messages and a report table which is consisted of node ID both for suspecting and reporting when the malicious nodes behave normally during the route discovery, but the other hand they drop and modify packets, or falsely report other nodes as malicious during the data transmission. Our proposed scheme is applicable to not only DSR but aiso AODV. And we provide some simulation results of our proposed scheme by comparing general AODV with our proposed scheme. Simulation results show that our Proposed scheme outperforms general AODV in terms of average packet loss ratio and packet delivery ratio.