• Journal of Digital Convergence
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• v.14 no.10
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• pp.303-310
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• 2016

Due to the ossification of the Internet, it is difficult to accommodate variety services. One of the efficient solution to this problem is network virtualization. It allows multiple parallel virtual networks to run on the shared physical infrastructure. It needs new resource allocation mechanism to share efficient physical resources. In this paper, we present efficient bandwidth allocation algorithm for virtual network request with high service priority. Our proposed algorithm can withdraw allocated bandwidth from low-level priority virtual network and maintain low-level virtual network service. We evaluated the performance of our proposed algorithm using simulation and found the improvement of approximately 8% acceptance rate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1673-1678
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• 2009

Multicast can transmit data packet to multiple terminals by using only one transmission and enhances the system performance. However, the multicast transmission rate is fixed and the system performance is not optimized. In this paper, we propose an adaptive multicast rate control method. In the proposed method, orthogonal subcarrier is assigned to each terminal. Each terminal informs the channel status using the allocated subcarrier. Transmitter selects the optimal rate using the feedback information. With the proposed adaptive rate control method, the system performance is enhanced compared with the legacy multicast method.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.555-556
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• 2011

오늘날 전기는 물과 같이 일상생활에 없어서는 안 될 생활 필수품이다. 특히 21세기는 IT, 디지털, 초정밀 산업의 시대로 순간정전에도 민감하게 반응하는 고품질의 전력이 요구되는 시대이다. KEPCO는 세계 최고 수준의 전기품질과 저렴한 요금으로 모든 국민에게 안정적으로 전력을 공급해야 하는 막중한 책임이 있다. 따라서 고품질의 전력을 주요 수요지로 수송하기 위한 송전선로와 변전소의 적기 건설을 위한 효율적이고 체계적인 프로젝트관리 중요성이 대두되었으며, KEPCO는 경영의 투명성을 제고하고 회사내부의 자원 및 업무 프로세스를 통합관리하고자 도입한 전사적자원관리(Enterprise Resource Planning; ERP) 시스템내에 송변전 건설 프로젝트 시스템(PS)을 구축함으로써 송변전건설 프로젝트 관리업무를 ERP라는 통합된 환경에서 수행할 수 있게 되었다. 그러나 최근 생활수준의 향상에 따른 송변전 건설관련 민원과 각종 건설규제 법률 강화 등으로 보다 효율적이고 통제 가능한 송변전설비 건설프로젝트 관리의 필요성에 대한 요구가 지속적으로 제기되었다. 이에 본 논문에서는 KEPCO의 효율적인 송변전 건설사업 공정관리를 위한 ICT기반의 건설 프로젝트 관리 방안에 대해 살펴보고자 한다.

• Journal of the Korean Society for information Management
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• v.24 no.4
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• pp.173-189
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• 2007

By measuring satisfaction index of the users of Information System, it is possible not only to estimate ROI(Return on Investment) but also to draw the device for the efficiency and improvement of the System. This study tries to give User Satisfaction Index Model for the System, and present operators and managers of the system with the method for improving satisfaction and efficiency by measuring the User Satisfaction Index of representative information systems. For this, the survey was carried out for the representative information systems. On the basis of the analysis, Satisfaction Index was drawn and through Matrix Analysis, the strategy for system improvement was derived.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.59-60
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• 2009

Steel fibers are recently well recognized for good composite/strengthening materials because of their ductile behavior and good performance on crack control and shear behavior compared to concrete materials. Especially, the great improvement in shear strength by steel fibers led researchers to be involved in many experimental studies. However, our understanding on the complex shear behavior of the steel fiber reinforced concrete(SFRC) members are still very limited, and the fundamental test data are also not enough. In this study, therefore, 4 SFRC specimens were fabricated and tested, from which the effectiveness of steel fibers as shear reinforcement were evaluated. The test results shows that the shear strength of SFRC members increases as the amount of steel fibers increases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.784-791
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• 2005

To provide VoD Service on the Internet VoD server is required to have a large amount of system resource and network bandwidth. Therefore, overlay Multicast schemes are considered as suitable alternatives but they also have some drawbacks to support on-demand media services. In this paper, we propose an overlay multicast based on-demand media service scheme which could exploit server's system resource and its network bandwidth efficiently. Proposed scheme uses shared buffer of clients involving the relay of traffic and Patching while it gives no restrictions to this scheme compared with unicast. Our simulation results show that proposed scheme can support more user than unicast and improve the network performance at the same time.

• Journal of Digital Contents Society
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• v.17 no.4
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• pp.235-241
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• 2016

EPG (Electronic Program Guide), which was born with the development of digital broadcasting technology, is becoming a successful data service in the environment that a digital broadcasting station operates more than one hundred channels. In the circumstance, the request for the development or renewal of EPG frequently occurs and so the developers are looking for ways to improve the efficiency of the EPG development. This paper addresses the need of the developers by devising an EPG feature model based on FODA and the test-cases for each feature of the model. Utilizing the EPG feature model and the test-cases, the EPG development process, especially the phases of requirement analysing and test-case designing can be improved.

• Journal of KIISE:Software and Applications
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• v.26 no.4
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• pp.462-472
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• 1999

능동적 시간지원 데이터베이스 시스템은 시간지원 데이터베이스 시스템에 능동규칙 시스템을 통합하여 구성한 진보된 데이터베이스 시스템이다. 이 시스템은 추세 분석, 상태 관찰을 통한 경보,고장에 대한 예측, 금융 시스템 및 공정 제어 등과같은 고도의 응용에 효과적으로 대응할수 있다. 그러나 능동적 시간지원 데이터베이스 시스템은 시간 차원을 갖는 다차원 데이터공간에 대해 처리해야 하므로 그 처리비용이 매우 높으며, 규칙 처리에 의한 시스템 부하가 매우 증가할 수 있다. 따라서 효과적 규칙 처리방법에 대한 연구가 수행되어야 한다. 한편 규칙의 성능에 대한 문제는 일반적으로 조건 평가 방법의 효율성에 달려있다. 특히 데이터의 시간차원을 고려한 시간지원 능동규칙의 경우 시간 영역에 따라 규칙에 의해 처리되어야 할 데이터 량의 증가하고 이에 다라 성능의 차이가 많이 나므로 더욱 문제가 된다. 따라서 이 논문에서는 능동적 시간지원 데이터베이스 시스템을 위한 시간지원 능동규칙의 성능향상을 위해 조건 평가를 검토하고 시간지원 차분에 의한 시간지원 점진적 평가연산을 제시하였다. 아울러 이 시간지원 점진적 연산자를 적용한 조건 평가 예를 보이고 이 연산자의 효율성을 증명하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.11
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• pp.810-819
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• 2006

This paper proposes an Adaptive Double Buffer Model. As a new FIFO buffer model, this technique minimizes packet losses from network congestion by logically managing buffers. It allocates the spare spaces of non-congested buffers to congested buffers by allowing receive/send buffers to share two queues, and hence it minimizes packet losses. In contrast to the buffer model utilizing a free list, this buffer model can prevent the bubble phenomenon caused by a memory leak and thereby apply to a network buffer in a restricted environment. Also, compared with the model using an way, this model brings maximum 100 percent improvement in accepting packets and compared with the model utilizing a free list, this model has the similar efficiency Results of the performance test on Adaptive Double Buffer Model, shows that this proposed model decreases packet losses and enhances memory efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3B
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• pp.123-134
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• 2008

In this paper, a routing algorithm for wireless sensor networks is proposed to improve the efficiency of energy consumption in sensor nodes. Each sensor node has the value called ‘Flooding Level’ obtained through the initial flooding from a sink node instead of sending beacon messages in multi-hop sensor field. This value can be used for guaranteeing the sensor nodes to connect with a sink node and determining the roles of cluster-head and cluster-gateway node efficiently and simply during the clustering. If different algorithms are added to our protocol, it will work better in the side of energyefficiency. This algorithm is evaluated through analysis and extensive simulations.