• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.476-489
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• 1999

HW/SW codesign is integrated design of systems implemented using both hardware and software components. Many design tools has been developed to support this new paradigm, so far. Current codesign tools are not widely used as been expected because of variety problems - rapidly evolving technology, platform dependency, absence of standard specification method, inconsistent user interface, varying target system, different functionality In this paper, we propose a web-based distributed HW/SW codesign environment to remedy this kinds of problem. Our codesign environment has object-based 3 tier client/server architecture. It supports collaborative workspace through session service. Fully object-oriented design of user interface(OOUI) enables easy extension without change of user Interface. Furthermore it contains transaction server and security server for efficient and safe transfer of design data. To show a validity of our design, we developed prototype of web-based HW/SW codesign environment called WebCEDA. Our model of HW/SW codesign can be used for web-based generic CAD tools.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.237-242
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• 2014

Recently, wind energy is expanding to combination of computing to forecast of wind power generation as well as intelligent of wind powerturbine. Wind power is rise and fall depending on weather conditions and difficult to predict the output for efficient power production. Wind power is need to reliably linked technology in order to efficient power generation. In this paper, distributed power generation forecasts to enhance the predicted and actual power generation in order to minimize the difference between the power of distributed power short-term prediction model is designed. The proposed model for prediction of short-term combining the physical models and statistical models were produced in a physical model of the predicted value predicted by the lattice points within the branch prediction to extract the value of a physical model by applying the estimated value of a statistical model for estimating power generation final gas phase produces a predicted value. Also, the proposed model in real-time National Weather Service forecast for medium-term and real-time observations used as input data to perform the short-term prediction models.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.17-27
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• 2007

The enhanced distributed channel access (EDCA) of IEEE 802.11e has been standardized for supporting Quality of Service (QoS) in wireless LANs. In the EDCA, support of QoS can be achieved statistically by reducing the probability of medium access for lower priority traffics. In other words, it provides statistical channel access rather than deterministically prioritized access to high priority traffic. Therefore, lower priority traffics affect the performance of higher priority traffics. Consequently, at the high loads, the EDCA does not guarantee the QoS of multimedia applications such as voice and video even though it provides higher priority. In this paper, we propose a simple and effective scheme, called deterministic priority channel access (DPCA), for improving the QoS performance of the EDCA mechanism. In order to provide guaranteed priority channel access to multimedia applications, the proposed scheme uses a busy tone for limiting the transmissions of lower priority traffics when higher priority traffic has data packets to send. Performance of the proposed scheme is investigated by numerical analysis and simulation. Our results show that the proposed scheme outperforms the EDCA in terms of throughput, delay, jitter, and drop under a wide range of contention levels.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1530-1538
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• 2009

KISTI-ACOMS ver. 2.0 has been distributed to more than 340 academic societies and used by more than 130 academic societies for 4 years since 2005 and still is desired for use by lots of other academic societies. But contrary to the desire and requests for system upgrades of academic societies, ACOMS has not been improved for last 3 years and some academic societies began to use domestic or foreign similar pay online peer review systems. In this paper, a new integrated portal service system is suggested in order to attempt national production cost-saving and quality improvement of academic information by creating and collecting high quality scientific and technologic academic information inexpensively. We come up with methodology of integration and utilization of a personal academic activity portal system interoperable with other services of KISTI, an open citation reference database automatically constructed by authors' activity and a journal evaluation system based on impact factor.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.2996-3009
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• 1997

A lot of talks on the Quality of services (QoS) so far were limited only either for the network itself or for the end system, But, recently it is becoming more important to have the seamless end-to-end QoS support to meet the networked multimedia service requirements This paper proposes the QoS based resource management architecture which supports the large scale distributed systems under heterogeneous environment. The architecture introduces a couple of key concepts such as abstractions and algorithms. Abstractions capture the three perspectivest found in all systems: application, resource, and system, on the ofter hand algorithms manage system resources based on information in the three abstractions. We also explain the on-line resource management flow as well as the benefit function which specifies the level of benefit accrued to the application user as a function of the level of service provided by the system. At the end of the paper, the QoS based resource management applied to the tele-seminar application is described to show its practical utilization.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.47-59
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• 2003

The Internet telephony service is one of the commercially successful Internet application services. VoIP technology makes the service come true. VoIP deploys H.323 or SIP as the standard protocol for the distributed multimedia services over the Internet in which QoS is not guaranteed. VoIP carries the packetized voice over the RTP/UDP/IP protocol stack. The data transmission trouble is caused by UDP when the service is provided in private networks and some ISP-provided Internet access networks in the private address space. The Internet telephony users in such networks cannot listen the voices of the other parties in the public Internet or PSTN. Making the problem more difficult, the Internet telephony service considered in this paper gets the incoming voice packets of every session through only one UDP port number. In this paper, three schemes including the terminal proxy, the gateway proxy, and the protocol translation are suggested to solve the problems. The design and implementation of the NAT proxy server based on gateway proxy scheme are described in detail.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.294-296
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• 1998

As the state of the art for handling Multimedia on the internet is developed a new system called WebCAM which services video and image came out. However, WebMIC site for audio services are still rare. In this work, we developed a system which enables anyone to listen audio in real-time through the internet. WebMIC system is implemented by connecting a server with a microphone and the recorded audio files are stored in a Database system. Because the microphones can be distributed sporadically, the developed system can be utilized for managing and advertizing a location. It also can be used to reduce the cost for the existing management system which is almost met by personnel expenses. Anyone who can connect to the internet can get this WebWIC service, so this system can produce a good effect if used in advertising any tourist resort.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.283-286
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• 2011

무선 멀티홉 네트워크에서 멀티미디어 트래픽의 QoS(Quality of Service) 지원을 위하여 EDCA(Enhanced Distributed Channel Access) 기반의 동적 우선순위 할당 기법이 다수 제안되었다. 해당 기법들은 각 홉에서의 최소한의 전송 지연 보장을 위하여 클래스별 예상 지연 시간을 계산한다. 하지만 각 클래스별 예상 지연 시간의 계산은 무선 채널에서의 간섭, 충돌 및 링크 품질에 영향을 받기 때문에 정확한 예측이 어렵다. 본 논문에서는 EDCA 기반의 동적 우선순위 할당을 위한 정교한 클래스별 지연 시간 예측 기법을 제안한다. 제안하는 기법은 무선 채널의 링크 품질과 전송 패킷의 크기를 고려하여 좀더 실제와 유사한 지연 시간을 예측할 수 있다. 실험을 통해 제안하는 기법이 기존의 기법보다 정확성이 높으며 이를 통해 동적 우선순위 할당 기법의 성능을 향상시킬 수 있음을 확인하였다.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2252-2254
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• 1998

As the state of the art for handling multimedia on the internet is developed a new system called WebCAM which services video and image came out. However, WebMIC site for audio services are still rare. In this work, we developed a WebMIC system which enables anyone to listen audio in real-time through the internet. WebMIC system is implemented by connecting a server with a microphone and the recorded audio files are stored in a Database system. Because the microphones can be distributed sporadically, the developed system can be utilized for managing and advertizing a location. It also can be used to reduce the cost for the existing management system which is almost met by personnel expenses. Anyone who can connect to the internet can get this WebMIC service, so this system can produce a good effect if used in advertising any tourist resort.

• Annual Conference of KIPS
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• 2001.04a
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• pp.155-158
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• 2001

본 논문은 주문형 서비스의 한 분야로서 부족한 네트워크 자원을 고갈시키지 않을 뿐만 아니라 서버의 부하를 크게 경감시켜 MOD의 성능을 최대화시켜 효율적인 노래방 서비스를 위한 새로운 프락시 캐슁을 제안한다. 제안된 프락시 캐슁 구조는 일반적인 unicast 전송으로 멀티미디어 데이터를 서비스 받고 동시에 요청된 데이터가 다른 종단노드(HEN)에 이미 캐슁 되어 있을 경우 후 순위 예약 곡들을 그 종단노드(HEN)로부터 데이터를 전송 받아 스위칭 에이전트(SA)의 스위칭 테이블을 통해 미리 디스크에 저장하여 unicast 채널의 서비스 종료된 다음 후 순위 예약 곡을 서비스 받는 방법을 사용한다. 제안된 분산 프락시 캐슁은 예약 곡목이 많을수록 서버 부하와 과도한 네트워크 트래픽으로 인한 병목현상으로 인한 지연을 크게 감소시킬 수 있고, 시뮬레이션을 통해 성능의 우수함을 확인하였다.