• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.493-502
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• 2003

In this paper, to solve some problems of the Mobile IP and local registration strategy we propose a method that can effectively support real-time traffics sensitive to delay time and packet loss. The proposed method reduces the registration time after a Mobile Node's movement between networks by carrying out the pre-registration for the domain which it will move into the network information of the link layer of cdma2000 system, at the boundary cell's handoff zone. Through the cost analysis and simulation it is shown that the proposed scheme yield a better performance compared with the Mobile IP and local registration strategies in terms of packet loss for parameters; variation of the velocity of a Mobile Node, and a distance between the Mobile Node and home networks, etc.

• Annual Conference of KIPS
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• 2002.11c
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• pp.1677-1680
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• 2002

홈 네트워크에 대한 관심이 높아지면서 각 정보가전들이 점점 지능화 되어가고, 정보가전의 데이터 서비스에 대한 욕구가 증가하면서 정보가전용 데이터들을 위한 규격이 필요하게 되었다. 규격화가 됨으로써 정보가전용 데이터들의 효율적인 관리와 적은 비용의 유지보수가 가능하게 된다. 데이터 표준화 도구로 주목을 받는 XML을 기반으로 정보가전용 데이터를 규격화하면 개발의 확장성 측면에서 바람직하며, 이를 통해 앞으로 개발될 새로운 관련기술들을 보다 쉽게 적용할 수 있다. 본 논문에서는 정보가전용 데이터 응용 프로그램의 요구 사항을 분석하고 이를 토대로 댁내의 정보가전 및 각 정보가전에 대한 데이터와 메시지들을 추출하고, 이를 이용하여 인터넷 정보가전용 규격에 대한 두 가지 방법을 제안한다. 첫 번째 제안의 내용은 추출한 데이터 대한 XML 규격화이고, 두 번째는 HDAL(Home Data Access Library)을 이용한 클라이언트와 서버 사이의 주고받는 SOAP 메시지들에 대한 XML 규격화이다. 이 두 가지 제안에 대해 구체적으로 기술하고, 이 제안이 홈 네트워크 환경에서 사용되는 예를 직접 제시한다.

• Journal of Navigation and Port Research
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• v.38 no.2
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• pp.171-176
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• 2014

Companies are facing challenges to have high competitiveness because of continuous oil price rising and CO2 emissions regulations. Thus, companies are trying hard to construct effective logistics and operation system to achieve high customer service quality and saving cost. Also the ec-friendly idustrial complex is needed. Busan is in process to construct GILC(Global Industry Logistics City) in west Busan province to achieve high competitiveness and support lack of industrial complex. To construct this kind of logistics industrial complex, it needs logistics system through proper policy and freight transportation co-operation. Especially, efficient management through logistics hierarchy construction in industrial complex is very important for low cost and eco-friendly point of view. Therefore, this paper aims to analyze logistics system and suggest operation model to present logistics complex construction base data.

• 전자공학회논문지 IE
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• v.49 no.2
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• pp.58-64
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• 2012

In this paper, we proposed a distributed gateway for ubiquitous healthcare system. We also designed and implemented protocol conversion and processing algorithms to exchange a seamless information, the bio signals between the databases and the receiving devices from ZigBee to gateway and from the gateway to database and network. The distributed gateway system consists of the bio signal acquisition, ZigBee modules, distributed databases, and gateways. The bio signals detected by the ZigBee module are sent to the gateway. The distributed gateway analyzes the data being transferred, sends those to the receiving devices, and lets the authorized personnel access. The proposed system can be utilized in various fields including activity analysis for the elderly, security systems, home network service, and so on.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6A
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• pp.624-634
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• 2008

The mobile station which is about to do handover in IEEE 802.16e networks scans its neighboring base station channels to decide its next target base station. However, due to the lack of location information of its subscribers, the serving base station cannot provide any reliable candidate channel which is actually attachable by the scanning mobile stations, which makes the mobile station suffer from the long scanning time. Sometimes, long scanning time may cause the degradation of quality of service due to repeatable scan-duration or failure to start the handover procedure in time. To overcome these problems, in this paper, we propose a new protocol so called fast group scanning scheme, in which multiple mobile stations form a group to scan their neighboring base station channels simultaneously. Main contribution of this proposal is to find and decide a reliable target base station within a short scanning time. The fast group scanning scheme can be deployed to the cell network of the serving base station with a dynamic neighboring base station list management.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.455-461
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• 2008

Enhanced Distributed Channel Access (EDCA) is a channel access scheme adopted by the IEEE 802.11e draft standard for QoS-enabled wireless local area networks. It classifies traffic into separate Access Categories (ACs) and achieves service differentiation by allowing each AC to have its own values of channel access parameters. This paper proposes a scheme to dynamically adapt the EDCA parameters to traffic environment so that they both maximize the throughput of non real-time traffics and meet the delay and throughput constraints of real-time traffics. For this purpose, we develop a design algorithm for efficient exploration of the EDCA parameter space. Using the algorithm, we derive a Pareto curve fur delay-throughput trade-off in each anticipated traffic environment. The Pareto database can then be used to optimally adjust the parameter according to the traffic environment and administrative policies. Simulation results show that compared with the default parameter configuration, the proposed scheme is better for delay, throughput guarantee and can improve the throughput of non real-time traffics by 12% on average.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.613-624
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• 2002

Within the past decade, TCP/IP network environment has been explosively widespread all over the world. As the internet and the WWW expand their boundaries, the network traffic caused by data transfers over the internet has also increased. In this paper, we present the design and implementation of a WebTraMAS (Web-based Traffic Monitoring and Analysis System) which can resolve the shortcomings of current management approaches, particularly on the network traffic monitoring and analysis. The WebTraMAS presented in this paper performs the network management activities based on the parameters related to the MIB-II of SNMP and the parameters related to the QoS such as network performance and fault. The proposed WebTraMAS, implemented using the WWW technology, is able for the network manager to manage the network easily and platform independently with the performance analysis of internet traffic.

• Journal of Information Management
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• v.42 no.4
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• pp.75-94
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• 2011

The purpose of this study is to analyze the domain on the field of Electrical Engineering in Korea by the author bibliographic coupling analysis. The data set contains a total of 2,157 articles from two core journals with 23,411 citation data from 2005 to 2009 published in two prestigious journals. In order to achieve the purpose of this study, MDS analysis, clustering analysis and network analysis were used to examine core subject areas. In addition, the centrality analysis in the weighted networks was used to explore the key authors in this field such as the top global centrality authors and the top local centrality authors. The findings of this study can be utilized to guide the current research trend and author network for collection development and information services in the field of Electrical Engineering.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.99-106
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• 2011

The emerging of ubiquitous computing and healthcare technologies provides us a strong platform to build sustainable healthcare applications especially those that require real-time information related to personal healthcare regardless of place. We realize that system stability, reliability and data protection are also important requirements for u-healthcare services. Therefore, in this paper, we designed a u-healthcare system which can be attached to the patient's body to measure vital signals, enhanced with USN secure sensor module. Our proposed u-healthcare system is using wireless sensor modules embedded with NLM-128 algorithm. In addition, PS-LFSR technique is applied to the NLM-128 algorithm to enable faster and more efficient computation. We included some performance statistical results in term of CPU cycles spent on NLM-128 algorithm with and without the PS-LFSR optimization for performance evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.355-367
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• 2013

In the Policy and Charging Control(PCC) architecture of the 3GPP and WiMAX forum, the Policy and Charging Rule Function(PCRF) controls and configures the policies of quality of services(QoS) and accounting to a Policy and Charging Rule Enforcement Function(PCEF). In this paper, we categorize the errors into three types that include a disconnection with peer entity, a delayed or no response and a response with failure result, and propose a scheme to automatically synchronize the data between the PCRF and the PCEF for each type of error. Also, we conduct a quantitative analysis to see how much it can help to maintain the cell capacity of the mobile VoIP service in a WiBro network, which is implemented in Korea according to the standards of WiMAX. We can see that our proposed scheme improves the performances of PCC by preventing the waste of radio resources, the overload of systems, the memory leakage of servers, the system shutdown, and so on. We have validated the scheme by implementation, and reflected it in WiMAX standard documents.