• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1274-1284
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• 1998

Multicasting plays an important role in providing multimedia services like audio and video conferencing and has been actively studied for many years. The study of multicasting has been mainly focused on finding a low-cost tree on the assumption that every edge of the tree has enough link capacity to be allocated to the amound of bandwidth required by a service. In some cases, however, a multicasting tree whose some edges do not have enough bandwidth to be allocated may exist. A typical example of this case is to multicast among the group users located in the different sub-networks in the interconnected networks composed of the high bandwidth networks such as B-ISDN and the low bandwidth networks such as PSTN and PSDN. This paper proposes a novel multicasting protocol for providing multimedia services in a wide area network interconnected by multiple heterogeneous networks. First, the paper discusses the inherent limitation of present multicasting protocols for the case. Second, se introduce a new concept, multiple QoS's for a service, which extends the implicit assumption that only one QoS is assigned to a service in order to overcome this limitation. Third, our multicasting protocol is designed based on the current Internet protocol stacks. Last, we perform simulations for possible scenarios to provide multimedia services in the network and analyze their pros and cons.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.817-826
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• 2005

BcN(Broadband convergence Network) is being developed in order to support a variety of network applications, with enhanced capabilities of QoS(Quality of Service) provisioning and security, and IPv6. In a high-speed network environment such as BcN, it if more likely for the network resources to be exposed to various intrusion activities. The propagation speed of intrusion is alto expected to be much faster than in the existing Internet In this paper, we present a multi-domain security management framework which my be used for a global intrusion detection at multiple domains of BcN and describe its characteristics. For the performance evaluation, we first present test results for the security node and compare with other products. Then we design and Implement an OPNET simulator for the proposed framework, and present some simulation results. In the simulation model, we focus on the performance of alert information in the security overlay network.

• The Journal of the Korea Contents Association
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• v.6 no.3
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• pp.1-11
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• 2006

With the improvement of information telecommunication technology, the various service in broadband integrated services digital networks have a wide range of delay, delay jitter and cell loss probability requirements according to traffic specification. Therefore, the design of appropriate control schemes that can satisfy the cell loss, delay requirements with various traffic specification for B-ISDN is an extremely important challenging problem. In this paper, we propose a priority control scheme using a window counter and a cell counter per each type of class. In the proposed priority control scheme, for satisfying required service quality, we performed the priority control scheme using the delay/loss factors obtained by comparing window counter with cell counter. The performance of proposed control scheme is estimated by computer simulation. In the results of simulation, we verified that the proposed method satisfied per class requirements as the results showed that cell loss probability has a order of video, data, voice and delay time has a order of video, voice and data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.770-777
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• 2007

Smaller cell size in the micro-cell or pico-cell structure brings about more frequent hand-overs between cells, and higher speed movement of the mobile terminal makes short the permissible time interval for executing these hand-over procedures. In this situation the hand-over failure may occur or some packets may be lost during the hand-over. Moreover a rapid degradation of throughput is triggered by packet re-transmission for compensating such errors. The QoS (Quality of Services) of mobile multimedia applications with higher bits rate requirements and higher speed mobility are severely affected by even shot service interruption. This paper proposes a new hand-over scheme to provide seamless services in the next generation mobile communication systems. Simulation is done to evaluate the performance of the proposed scheme based on its hand-over failure rate and packet loss rate.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.343-348
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• 2014

A routing scheme called MCS-NLTC using a self-configuration marine network model and the diversity and heterogeneity of broadband wireless access technologies is newly proposed. The MCS-NLTC algorithm selects optimal nodes and carriers for every hop in optimal routes based on not conventional hop counts but normalized distances to destination ships (location information of destination ships). Normalized transmission characteristics of applications and carriers are considered to get optimal routes as well. The location information enhances convergence speed to get destinations, which makes the route search time faster. Evaluated performances are compared with those of the schemes based on max-win (OMH-MW), and normalized transmission characteristics (MCS-NTC).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.387-393
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• 2013

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an installation of LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. We define the mode change in a femtocell gateway for supporting the offload of the general traffic between the headquarter and a remote shipyard, the offload data management and trigger message, and cache entry fields. To show the operation of our proposed off-loading function, we consider the transcipient message flow at the femtocell gateway with its state transition diagram. Hence, it is expected to increase the productivity of shipyard industry with mobile communications and broadband Internet technologies.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.88-93
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• 2017

Policy maker inevitably faces two restraints once they attempt to accomplish $4^{th}$ Industrial Revolution through development of Industrial Internet of Things(i.e. IIoT). One is to construct physical network by substituting old equipment and infrastructure into smart equipment and the other is to connect the physical network into national telecommunications infrastructure. Australia, as she proceeds National Broadband Network programme, has assembled all medium of telecommunications to provide every Australian premises regardless to its physical location by creating wholes-sale only carrier, NBN co. At the same time, Australian government also provides its own IIoT policy; Co-development and New-Development projects. Meanwhile, NBN co. has launched its own two communication satellites in 2015 and 2016 to replace the old satellite communication services depended on the other companies' satellites. This article, in the end, analyses the role of satellite communication in $4^{th}$ industrial revolution with case study on Australian policy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.740-746
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• 2013

Machine to machine (M2M) communication is a converged ICT(Information and Communications Technology) platform which can utilize communications services among people and things anytime, any place in realtime. The M2M platform consists of three components; M2M area networks sensing and generating data of things by various sensors and devices; public networks transporting those data; and M2M applications utilizing the aggregated data. There exist however two practical obstacles to realize the M2M communications in terms of interoperability between the WCDMA-based public network and the local networks based on W-Fi or ZigBee; one is the cost problem required to access the public network, and the other is the lack of a cost-effective modem or gateway to connect two different networks. In this paper, we proposed and implemented a novel M2M platform based on PWW (Person Area Network) which can resolve those two issues by using a proposed gateway connecting the local network and smartphones as application devices without access the WCDMA-based public network. We have shown that the proposed platform is very practical to adopt to the real environment by actual testing with the own developed smartphone applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1139-1145
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• 2014

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart communicating various multimedia information with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an additional function of an LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. To reduce traffic of duplicated requests in shipyard, we apply a D2D communication scheme for supporting communication between shipyard equipments without IP service network. Hence, it is expected to increase the productivity of shipyard industry with mobile communications, D2D and broadband Internet technologies.

• Proceedings of the ESK Conference
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• 1995.04a
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• pp.15-15
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• 1995

90년대 중반에 이르러 세계는 정보화사회로의 진입이 예고되고 있으며21세기는 지 식과 정보로 이루어진 사이버스페이스(Cyberspace)가 지배하는 가상사회(Virtual Society), 그리고 나아가 가상세계(Virtual World)가 될 것이다. Cyberspace는 컴퓨터와 통신망을 통한 다양한 멀티미디어 정보통신 서비스에 의해 형성되는 가상의 공간을 의미한다. 이러 한 21세기 정보화사회의 특성은 사회적 그리고 기술적 Paradigm 변화의 추세와 속성이 변질되고, 정보사회의 변화에 대해 그 근간이 되는 21세기 정보통신기술은 각각 정보의 운반수단, 정보용량, 정보신호처리방식, 통신영역, 그리고 정보통신 자원 등의 영역에서 그 기준과 수준이 변화할 것이다. 본 논문에서는 21세기 사회의 변화에 적응하는 정보통신 기술의 진화 모델과 차세대 정보통신 기술의 예측항목들을 분석하여 지능화(Intelligent), 복합화(Multimedia), 개인화(Human) 등의 IMPH의 특성 요소를 정의 한다. 정보화사회에 있어서 인간 중심의 정보통신 체계(Human Oriented Information and Tele-communication Service System)는 인간의 성능과 특성에 가장 최적합한 서비스 기능 체계를 구축하기 위해서 인간의 각 정보통신 처리 영역인 Perceptual Processor, Cognitive Processor에 대한 구현 서비스들의 정의와 그와 관련하여 예측되는 연구 및 기반기술 과제를 기술한다. 또한, 광대역 멀티미디어 정보통신 서비스들의 형태, 응용, 정보 요소, 기술적인 대칭성과 연결형태 등을 분석하고 4단계로의 차세대 정보통신 기술의 연구개발 전략과 방안을 제시한다.