• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2521-2532
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• 1997

The next generation internet protocol, IPv6, have been developed by the IETF according to the requirements of enhancement of classic IP protocols to satisfy the lack of Internet address space as well as the support of multimedia applications. This paper presents an implementation of IPv6 protocols on the Windows NT kernel environment. In this work, we developed and also tested the basic functions, required for operating as an IPv6 host, such as IPv6 header processing, IPv6 address handling, control message processing, group membership processing and neighbor discovery functions. The implemented IPv6 protocol driver module is connected to the lower network interface card through NDIS, a standard network interface. And this driver module that operates within kernel, is implemented as it is connected to upper user applications and lower NDIS using dispatch and lower-edge functions. The developed IPv6 protocol driver can provide not only enhanced performance because it is implemented in kernel mode, but also convenience of usage to the application developers because it gives user interface as a dynamic link library.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3097-3110
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• 1997

As to the recent advances in computer technologies and high-speed networks, telecommunication services and provision of multimedia services will be provided on the basic of a new software architecture adapting networking infrastructure on open information networking architecture. In this paper, the video conference services has been selected as a target service example because it is expected to become one of the most important services on the full service network. In fact, it can be viewed as the basis for providing telecommunication services such as video telephony and video conferencing. This paper presents the prototyping of TINA (Telecommunication Information Networking Architecture) based desktop video conference system using the concepts of session management. The prototyping of desktop video conference system aims at assessing TINA concepts and refinement of the mapping between session graph and connection graph, and provides object modeling methodologies towards distribution and objected-orientation.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.478-480
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• 2001

인터넷이 널리 보급되면서 최근 무선인터넷과 네트워크의 최종점인 홈 네트워크가 최대 이슈가 되고 있다. 무선인터넷의 급속한 발전은 이동통신 단말기가 인터넷의 또 다른 연결 수단으로 인식되고 있으며, 이동통신 단말기를 이용하여 언제 어디서나 인터넷 접속이 가능하고 멀티미디어 서비스가 이동통신 단말기에서 가능하게 한다. 그뿐 아니라 기존 가전제품 및 장비에 대한 원격 조종을 가능하게 하는 블루투스 기술의 상용호가 멀지 않았으며 유선인터넷에서 이용되던 HTTP, XML, CGI, URL, SSL등의 기술이 무선 단말기의 저용량의 프로세서와 메모리, 작은 디스플레이, 베터리의 용량등을 감안한 새로운 프로토콜 기술들이 등장하고 있다. 인터넷의 급속한 발전으로 가전기기가 인터넷의 영향을 많이 받고 있으며 몇 년 지나지 않아 가전기기들이 인터넷에 연결 될 것이다. 본 논문에서는 댁내의 초고속 정보망구축의 관점에서 무선인터넷의 3세대와 홈네트워크의 연동방안과 일괄 제어 및 관리를 실현할 수 있는 고도의 중앙 집중식 관리에 대한 인프라를 구축해보고 해결해야 할 문제점에 대해 기술하고 결론을 맺고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.787-789
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• 2003

네트워크 상에서 특정의 시스템 또는 컴퓨터에 접속하려고 하는 사람이 정당한 사용자인지를 판단, 그 결과에 근거하여 접근을 제어하는 일련의 프로그램 또는 하드웨어 장치들을 인증 시스템이라 하며, 최근에 들어 정보보호 측면에 있어서 그 중요성이 커지고 있다. 본 논문에서는 인증 데이터를 암호화 또는 부호화 시켜서 전송하는 종래의 인증 알고리즘과는 달리, 인증 데이터를 이미지와 같은 제3의 미디어에 은닉시켜서 전송함으로써 인증을 실시하는 새로운 인증 기법을 제안함과 아울러 시뮬레이션 결과를 제시함으로써 제안된 방법의 유효성을 나타내고 있다.

• Journal of Korea Multimedia Society
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• v.2 no.3
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• pp.329-338
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• 1999

In this paper we propose a WATM MAC protocol called DTDD/PS (Dynamic Time Division Duplex using Poll/Select scheme). The idea of the DTDD/PS protocol is based that a radio cell is considered as queueing system. The MAC controller in base station is charged in coordinating terminals for the QoS requirement from each terminal. For that reason, terminals send it's own dynamic parameter represented its status, and controller controls the access of terminals and assigns time slots dynamically using received parameters. Therefore this system can satisfy the QoS of real-time service in wireless environments. To evaluate DTDD/PS protocol simulations are executed. In 25Mbps channel capacity, the voice and data coexist traffic situation, as the total number of terminal is increased, the delay of data terminals is increased rapidly. But the case of only increasing data terminals, the number of supported voice terminals is not varying. Therefore we can expect that DTDD/PS protocol can applied to multimedia traffic effectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.107-115
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• 2013

Smart appliances with multi-media and telecommunication equipments provide users complicated convenience functions. On the contrary, 8-bit controller-based low performance electronics still cannot afford such multimedia and telecommunication. If we find a way to have low-end electronics connected and provide complicated functions, they can be also made "smart". Fortunately, 8-bit controllers used in low-end appliances have UART, which can be connected to any of BlueTooth, Wi-Fi and ZigBee communication modules which can, in turn, communicate with smart devices. Any communication module can be attached to the low-end electronics due to the variety of smart devices' connectivity at the other side. Although the convenience functions seem complicated, they are actually macros in a script form composed of micro commands which implement the base functions of appliances. Since the kinds of the base functions are not that many, the low-end electronic appliances will become "smart" if their control program can be extended to execute sequentially the micro commands in any combination. Such simple innovation has not seen the world, until now due to the overhead of the additionally required hardware such as display devices and buttons. The high-quality display and touch screen functionalities of smart devices can replace the required hardware, and remove the overhead completely. In fact, the low-end appliances become smart as if an "evolution kit" is newly equipped.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.171-180
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• 2004

CDP(handoff Call Dropping Probability) and CBP(new Call Blocking Probability) have been used as two important call level QoS parameters in cellular mobile communications. But, many methods to reduce CDP without considering CBP have been studied, and hand-off call priority scheme has been introduced. But the use of hand-off call priority scheme increases CBP and decreases channel utilization rate depending on the number of reserved channel for priority. In this paper, we propose a CAC(Call Admission Control) algorithm with overflow and preemption to solve the problem caused by considering CDP and CBP in calculation of the number of channel reserved. The problem is the increase of CDP as the traffic load increases. In our CAC algorithm, hand-off call is permitted to use(overflow) unreserved and unused channel if there is no reserved and unused channel, and new call is permitted to use(preemption) the channel overflowed by hand-off call if there is no unreserved and unused channel. This mechanism of calculation of the number of reserved channel and CAC algorithm is expected to increase channel utilization rate, and can be applied to media-based QoS provision in cellular mobile communications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.565-572
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• 2007

3G Long Term Evolution (3G LTE) is a next generation cellular networks system capable or providing various mobile multimedia services by using OFDMA and MIMO based radio access technology. Among many differences from existing WCDMA based systems, the facts that 3G LTE uses Physical Resource Block (PRB) as its radio resources and provides all services through the PS domain make the development of new resource management schemes necessary. This paper proposes an adaptive partitioning based downlink call admission control scheme. It separates realtime call requests from non-realtime ones, specifies maximum allowable resource amounts for each type, but if the maximum is exceeded, call requests are accepted with probability proportional to remaining resource amounts. Despite the fact that such adaptive concept has been already adopted by other call admission schemes, the contributions of our paper, which are that we are able to find an efficient way to apply the proposed scheme exploiting PRB characteristics and measure the resource usage of base stations by PRB utilization and payload ratio, are still valid. When judging from simulation results in comparison with others, our scheme is able to prioritize realtime call requests over non-realtime ones, and at the same time, overall system performance is superior.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.123-132
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• 1999

A video conferencing system provides sharing the conference environment for geographically dispersed computer users who use the audio and video information. But the conventional video conferencing systems have some problems which are dependent on specific software and/or hardware and bound the certain platform and network environment. Furthermore the participants must know the information about other participants before joining the conference session and they have to use the same video conferencing system. This paper describes design and implementation of the video conferencing system on the WWW to solve the mentioned problems. The conference applications are transmitted from a WWW server and executed in the participants Web browsers. The participant can carry out conference services by using only the web browser. The WWW server takes charge of conferencing management including the information related to the participants and provides supported conference tools such as whiteboard, chatting and multimedia controls. Therefore the participants can easily join the conference sessions and perform conference working regardless of network connection situations. We used the Java to implement the seamless session connections and interaction between the conference participants which are the most important when implementing the video conferencing system on the WWW and used the ActiveX technology about the audio and video controls to make it easy the hardware control.