• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.385-386
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• 2012

기존 Telnet, FTP 도구를 통하여 사용자가 직접 Legacy 서버에 접속하여 작업을 하면서 내부정보에 접근하는 현황을 개선하여 사용자와 Legacy 서버 사이에 Gateway 형태의 일체형 S/W와 H/W Appliance 장비를 두어 Legacy 서버에 대한 접근제어, Packet Logging, Packet Filtering을 통하여 내부 중요정보에 대한 접근 통제, 내부정보 유출 차단, 감사 추적의 보안기능을 제공하는 시스템을 개발하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1075-1078
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• 2008

모바일 웹서비스는 점차 발전하고 있지만, 아직까지 제한된 디바이스의 성능 및 기술적인 요건, 서비스 시스템 통합화의 부재등으로 통해 최적화된 서비스를 제공해 주고 있지 못하다. 따라서 이를 지원하지 위하여 구조화된 서버환경에서 사용자에게 각각의 최적화된 서비스를 제공해 주고, 사용자의 선호나 사용방식에 따라 사용자에게 맞춤형 서비스를 제공해 줄 수 있는 미들웨어 시스템을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6B
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• pp.553-562
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• 2003

Supporting QoS (Quality of Service) for the multimedia applications becomes an important issue as the demand of multimedia applications increases. Thus, it is necessary for the application layer to have an efficient congestion control algorithm, which can support the multimedia applications' QoS requirements. In this paper, we propose a new application layer congestion control algorithm, called RRC-OTT (Receiver-based Rate Control with One-way Trip Time). RRC-OTT algorithm differs from the previously proposed algorithms in that the receiver takes the responsibility of the network congestion control. Thus, RRC-OTT algorithm can not only precisely estimate the network congestion using OTT (one-way Trip Time), but reduce the work load from the sender (e.g., the web server). Our simulation study shows that RRC-OTT algorithm can maintain the comparable link utilization to the previously proposed algorithms and keep the packet jitter low, which thus can help enhance the quality of multimedia applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.10
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• pp.930-936
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• 2014

Smart Multiple-Tap to be introduced in this paper, is an electronic device that controls the Multibple-Tap through the Smartphone. It runs on network and has an inbuilt Zigbee communication module. Thus, users can control home devices from remote through home server. Mentioned home server is operated as a gateway and is connected with smart devices on the Internet. To sum up, Users using this Smart Multiple-Tap can check the state information of the multi-tap ON/OFF and can control immediately by smartphone. also, Smart Multiple-Tap perfectly shut down the standby power. when users turn off each of the Smart Multiple-Tap's circle, It drives automatically lowest electricity-consuming mode and shut down the standby power by its own built-in SSR module. therefore, it will bring the energy saving effect on environment using Smart Multiple-Tap.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.705-707
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• 2000

본 논문에서는 교육 실험용으로 사용할 수 있는 실시간 시스템 프로토타입 tool kit을 개발하였다. 하드웨어 부분에서는 8개의 센서 입력 채널과 8개의 제어 신호 출력 채널을 가지는 AT(ISA) 버스용 I/O 보드를 제작했다. 소프트웨어 부분에서는 실시간 운영체제인 VxWorks 상에서, 이 I/O 보드를 제어할 수 있는 디바이스 드라이버를 구현하고, 이를 바탕으로 멀티 스레딩과 우선 순위 스케줄링을 이용한 세차장 모델 제어 프로그램을 제작했다. 또, 현재 부각되고 있는 인터넷을 통한 원격 제어를 실현하기 위해 TCP/IP 기반의 웹서버와 자바 애플릿으로 구현된 원격 제어 클라이언트도 내장시켰다. 그리고 이 tool kit의 효용성을 입증하기 위해 Lego Dacta를 이용하여 세차장모형을 제작하고 본 tool kit에 접속하여 인터넷에서 원격 제어가 가능한 실시간 새차장 시스템의 프로토타입을 구현하여 보았다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1685-1690
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• 2006

The future mobile communication system should be operated with hierarchical cellular system for providing high quality multimedia services within limited wireless resources. In this paper, we have studied a call admission control scheme applied in hierarchical CDMA cellular system nested with macro, macro, and pico cells. When the proposed call admission control algorithm was applied we got 20% more system capacity than no admission control was applied.

• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.101-110
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• 2008

Ubiquitous computing has extended the computer system into the whole physical space and has ushered the emergence of more dynamic distributed systems. This environment require unique QoS parameters for various devices, resources and user requirements. In this paper, we propose a new hybrid QoS management model which defines a static-dynamic QoS parameter that is more appropriate to the ubiquitous computing environment. This model consists of the QoS Control Management Module(QoS CMM) in the client side and the Resource QoS Management Module (RQoS MM) in the server side. The RQoS MM deals with the static QoS parameters and the whole QoS control of the distributed control(QoS CMM) in order to minimize server load in cases of multiple communication. Finally, we present the experimental result of our location based application using a graphical user interface that shows the multimedia service execution of selected client device types such as desktop PC, notebook and PDA.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.488-495
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• 2003

With the development of networks, multimedia communication has expanded its application field. From the remote control for household electric appliances to medicine, games, video conferencing and multimedia chatting, multimedia communication is being used in all parts of our lives. This multimedia communication requires the transmission of a lot of data at high speed. But if the transmission rate of the communication network exceeds the processing speed of being used in the high speed network environment, a bottleneck occurs in each node and deteriorates the performance of the network. This is the main reason for the slow speed of data transmission and packet loss. In this paper, considering the client's processing performance, reception performance was predicted and the way of flow control was shown. The computing performance of relevant Processor and its performance was estimated through the actual implementation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.96-103
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• 2009

This paper presents a L3 mobile terminal platform of the mobile terminal system which is a subsystem of HMm(Hig-speed Mobile Multimedia) system, which layer 3 control protocols such as RC(Radio Control), SC(Session Control), MC(Mobility Control) and application services such as VOD, FTP, VoIP for a multimedia mobile terminal are implemented on. The hardware platform is based on PXA255 and supports various interfaces and multimedia devices, and under the platform, an embedded Linux generated by the self-maden cross-toolchain, L3 control protocols and application programs were installed. The operation of HMm system under the HMm testbed has shown that this platform successfully supported SIP services, web browsing services, streaming services and etc as well as call processing. It could be the reference of the upcoming Fourth-Generation mobile terminal which the multimedia functionality will be enforced.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8S
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• pp.2748-2756
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• 2000

IMT-2000 시스템(International Mobile Telecommunications-2000 system)은 음성, 화상, 및 데이터 서비스등 멀티미디어 서비스 제공을 목표로 기존의 디지털 이동통신 시스템에 적용된 기본 기술에 새로운 시스템 개념과 각종 응용기술 및 망 기술이 접목된 차세대 이동통신 시스템이다. 본 논문에서는 동기방식의 IMT-2000 시스템의 핵심 시스템인 제어국(BSC : Base Station Controller)의 무선 트래픽 및 신호접속기능, 이동호 제어기능 및 운용보전기능의 설계 및 구현에 대하여 논하고자 한다. 또한, IMT-2000 시스템의 호처리 절차 및 핸드오프 처리절차를 제시한다. 주로 BSC의 서브시스템인 AIS(ATM Interconnection Subsystem), BIS(BTS Interface Subsystem), SDS(Selector Distribution Subsystem), CSS(Control & Signal Subsystem) 및 BEMS(Base station Element Management Subsystem)의 구조와 기능, 그리고 MS(Mobile Station),BTS(Base Station Transceiver Subsystem), BSC 및 MSC(Mobile Switching Center)간의 호처리 기능, 절차(핸드오프 기능 포함)를 설계, 구현하였다.