• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8A
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• pp.1398-1406
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• 2001

최근 초고속 통신망의 발전과 더불어 망을 통한 멀티미디어 서비스의 개발이 활발히 진행되고 있다. 특히 멀티미디어 서비스의 핵심 요소인 영상서비스에 관련된 많은 개발이 이루어졌다. 이러한 망에서의 영상서비스를 효과적으로 제공하기 위하여, 사용자로부터 요구되는 서비스 품질(QoS : Quality of Service)을 보장하고 관리하는 것이 서비스 제공의 핵심 사항이라 볼 수 있다. 최근 주문형 비디오(VoD : Video on Demand) 서비스와 같은 망을 통한 영상 전송이 실용화되고 있으며, 차세대 영상 압축 방식인 MPEG2 방식을 이용한 전송이 개발되고 있다. 이러한 망을 통한 MPEG2 서비스 시, 종단간의 QoS를 보장해 주기 위한 망 계층과 응용 계층간의 QoS 파라미터 측정과 이를 토대로 한 서비스 제공 및 관리가 필요하다. 본 논문에서는 MPEG2를 이용한 영상 전송 시 종단간의 QoS 측정을 위한 VoD 시스템 및 측정기 개발에 관해 논한다.

• Korean Journal of Comparative Education
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• v.24 no.1
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• pp.1-29
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• 2014

The purpose of this case study is to examine and compare the basic characteristics of quality assurance systems of the 3 leading countries in international higher education: Australia, Canada, and the Netherlands. The comparative analysis of the three cases demonstrates that, taking a more commercial stance on the international education service market, quality assurance systems of the 3 countries aim at facilitating effective promotion of student recruitment and enhancing their national brand image as advanced knowledge society. Consequently, rules and regulations of their systems are concerned primarily with strengthening institutional capacities to educate international students effectively, and, ultimately, improving their learning experiences in the host countries. Compared to these foreign cases, the newly-adopted quality assurance system in Korea places too much emphasis on internationalization process itself, thereby neglecting evaluation of educational capabilities of higher education institutions. Further implications for improvement of the Korean International Education Quality Assurance System(IEQAS) are discussed.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.4
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• pp.1-6
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• 1999

When continuous media are transmitted over the communication networks, asynchrony which can not maintain temporal relationships among packets my occur due to a random transit delay. There exist two types of synchronization schemes ; for guaranteed or non-guaranteed resource networks. The former which applies a resource reservation technique maintains delay characteristics however, the latter supply a best-effort service. In this paper, I propose a intra-media synchronization scheme to transmit continuous media on general networks not guaranteeing a bounded delay time. The scheme controls transmission times of the packets by estimating next delay time with the delay distribution So, the arriving packets my be maintained within a limited delay boundary, and playout will be performed after buffering to smoothen small delay variations. To prevent network congestion and maintain minimum quality of service the transmitter performs media scaling-down by dropping the current packet when informed excessive delay from the receiver.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.15-16
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• 2011

로봇사업은 전 세계적으로 급속히 성장하고 있는 분야로 미국, 유럽 등 많은 국가들이 막대한 자본을 투자하고 있으며, 우리나라에서도 차세대 전략 산업으로 선정하여 집중적으로 지원하고 있다. 현재 로봇 시스템 및 서비스의 복잡도가 증가함에 따라 소프트웨어의 개발비용, 인력, 유지보수 등의 문제를 해결하기 위해 OPRoS(Open Platform For Robotic Service)라는 로봇 소프트웨어 플랫폼이 개발 되었다. 하지만 OPRoS 실행엔진은 범용 운영체제 위에서 동작되기 때문에 로봇서비스의 QoS(Quality of Service)를 위한 실시간성을 보장하지 못한다. 본 논문에서는 범용운영체제인 윈도우즈 상에서 동작하는 로봇 소프트웨어 플랫폼인 OPRoS의 실행엔진에 RTiK(Real-Time implanted Kernel)을 이용해 실시간성을 보장할 수 있는 방법에 대해 연구 하였다. 또한 RTiK이 이식된 OPRoS 실행엔진의 성능을 측정하였다.

• Journal of Internet Computing and Services
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• v.9 no.3
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• pp.103-117
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• 2008

General customer uses internet, SMS(Short Message Service), ATM(Automated Teller Machine), DM(Direct Mail), and telephony services, etc, for service of big businesses and small and medium enterprises, securities, financial institutions, bank. In particular, the case of Fire insurance & Securities, financial institutions, banks must meet Real-Time constrain control through QoS(Quality of Service) ensure. In this paper, we design and implement a system model about Fault-Tolerance IVR(Interactive Voice Response) of Multi Channel Service based on CRM(Customer Relationship Management) environment for the first inbound position of customer. The proposed model can be widely used in Large-scale Customer Response service.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.129-132
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• 2003

In this paper, we propose the DQM - CBRP( Distributed QoS Monitoring - Cluster Based Routing Protocol ) routing protocol to provide Quality of Service guarantee for multimedia service in Ad hoc mobile network. This paper proves the DQM-CBRP can avoid message loss and is suitable to guarantee of QoS thru simulation of COMNET III.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.250-253
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• 2010

Underwater sensor network has attracted more and more attention from the networking research community recently. Most of traditional studies focus on the topology with a single gateway. Underwater sensor network consists of a variable number of sensors and multi-gateway to ensure the reliability of the network. In this paper, we propose a new MAC protocol that can reduce collisions among sensor nodes and improve QoS(Quality of Service) for underwater sensor network with multi-gateway. We evaluate the performance of the proposed scheme through simulation. Simulation results show that the proposed scheme outperforms the existing MAC protocol.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.34-42
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• 2008

MAC(Medium Access Control) is demanded to provide end-to-end QoS(Quality of Service) for a variety of traffic in the wireless networks. When all the traffic is integrated in the channel, the main difficulty of the MAC protocol is how to efficiently support multi-class traffic in the limited bandwidth wireless channel. In this paper, we proposed the dynamic bandwidth slot method for improving QoS of the real time traffics. In this paper, we used in-band scheme to send dynamic parameter and considering buffer size and delay variation, we enabled 2 state bits to send to base station in mobile station. The proposed algorithm is to guarantee QoS of real time traffic and maximize transfer efficiency in wireless networks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.3
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• pp.179-179
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• 2004

In the near future we can expect a change in charging the Internet service. The flat charging maybe replaced with a usage-based charging. In line with this movement, we propose a method of charging the assured-quality Internet services for the next generation network by introducing a UBC (usage-based charging) scheme over the conventional flat charging platform. First, we investigate the attribute of elastic traffic generated by assured services in IP network. Next, we propose a new method to relate the bandwidth usage with the pricing for the elastic traffic, which is based partially on the usage rate of the network bandwidth. Next, we propose a charging function for elastic traffic, which is applicable to any type of assured Internet services. Finally, we discuss the implication of the work via simple numerical experiments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.3
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• pp.21-28
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• 2004

In the near future we can expect a change in charging the Internet service. The flat charging maybe replaced with a usage-based charging. In line with this movement, we propose a method of charging the assured-quality Internet services for the next generation network by introducing a UBC (usage-based charging) scheme over the conventional flat charging platform. First, we investigate the attribute of elastic traffic generated by assured services in IP network. Next, we propose a new method to relate the bandwidth usage with the pricing for the elastic traffic, which is based partially on the usage rate of the network bandwidth. Next, we propose a charging function for elastic traffic, which is applicable to any type of assured Internet services. Finally, we discuss the implication of the work via simple numerical experiments.