• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1397-1402
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• 2021

The overlay2 file system is one of the union file systems that mounts multiple directories into one. The source directory used for this overlay2 file system mount has a characteristic that it operates independently of the write-able layer after mounting, so it is often used for container platforms for application delivery. However, the overlay2 file system has a security vulnerability that the write-able layer is also modified when file in the source directory is modified. In this study, I proposed the overlay2 file system protection technology to remove the security vulnerabilities of the overlay2 file system. As a result of empirically implementing the proposed overlay2 file system protection technology and verifying the function, the protection technology proposed in this study was verified to be effective. However, since the method proposed in this study is a passive protection method, a follow-up study is needed to automatically protect it at the operating system level.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2C
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• pp.139-147
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• 2006

This paper presents an overlay video multicast system over the Internet. The proposed system consists of two parts, i.e. overlay multicast tree suitable for the real-time video delivery and H.263+ rate control adaptive to overlay multicast tree. Overlay multicast tree is constructed to minimize the average time delay of members, and H.263+ rate control pursues a tradeoff between spatial and temporal qualities to enhance the human visual perceptual quality. Two systems are integrated and tested over the real Internet. And experimental results are provided to show the performance of the proposed system.

• Journal of Welding and Joining
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• v.27 no.3
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• pp.80-84
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• 2009

The Plasma Transferred Arc (PTA) overlay welding method is lately introduced as one of the most useful surface overlay method of the engine component. In this paper, the overlay welding on the SNCrW heat resisting alloy was conducted by the PTA overlay welding process using the super alloy powder. The characteristics of the overlay layers were investigated through the metallurgical and abrasive test. Experimental results showed that the overlay on the SNCrW heat resisting alloy surface was successfully made without hot cracking. The friction wear characteristics of the Co-base Stellite 6 overlayer were most superior. However the abrasive wear characteristics were most inferior in the Co-base Stellite 6 overlayer.

• Journal of Communications and Networks
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• v.12 no.2
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• pp.181-190
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• 2010

A multitude of overlay network designs for resilient routing, multicasting, quality of service, content distribution, storage, and object location have been proposed. Overlay networks offer several attractive features, including ease of deployment, flexibility, adaptivity, and an infrastructure for collaboration among hosts. In this paper, we explore cooperation among co-existing, possibly heterogeneous, overlay networks. We discuss a spectrum of cooperative forwarding and information sharing services, and investigate the associated scalability, heterogeneity, and security problems. Motivated by these services, we design Synergy, a utility-based overlay internetworking architecture that fosters overlay cooperation. Our architecture promotes fair peering relationships to achieve synergism. Results from Internet experiments with cooperative forwarding overlays indicate that our Synergy prototype improves delay, throughput, and loss performance, while maintaining the autonomy and heterogeneity of individual overlay networks.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.4-8
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• 2014

In this research, GTA overlay welding system is developed for inside of straight pipes in various diameter. It can be applied to oil, ship building and plant industry, especially pipes connected to pressure vessels, for the purpose of cost reduction by cladding inside of pipes with corrosion and heat resistant alloys such as stainless steel or Inconel. Developed system consists of GTA power source, torch, wire feeding system, automatic arc length adjusting device, CCD camera and cooling unit. Two types of pipe inside overlay welding system are developed. One is for maximum 3m pipe length with 3 inch ~ 12 inch pipe outer diameter. Another type can be applied to maximum 12m pipe length with 7 ~ 24 inch OD. Developed system successfully produced inside cladded pipe and the results are shown through cross sectional images of the pipes.

• Journal of the Korea Furniture Society
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• v.21 no.2
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• pp.126-132
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• 2010

High wear resistances are obtained with an additional coating of the surface of the decor film in the same operation of impregnating with low viscosity melamine resin by liquid overlay system. The cellulosic fibers have a good adhesion to the corundum particles and keep them sufficiently homogeneous in the blend with the resin. The amount of these fibers in nearly as big as it is in a common overlay in relation to the resin. Therefore these fibers keep the resin inside during the press process and consequently very the surface of the decor print of the film. That means that the corundum particles are equally dissipated throughout the entire layer over the decor. The change of the color of the print is nearly not visible as the particles are almost equally dissipated. Looking to the flooring purposes of liquid overlay one can see that by the lesser exposure of the corundum particles on the very surface, there is no longer an abrasive surface but a feeling like a normal melamine surface.

• Journal of Multimedia Information System
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• v.2 no.1
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• pp.163-170
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• 2015

Many overlay texts are artificially superimposed on the broadcasting videos by humans. These texts provide additional information to the audiovisual content. Especially, the overlay text in news videos contains concise and direct description of the content. Therefore, it is most reliable clue for constructing a news video indexing system. To make the automatic person indexing of interview video in the TV news program, this paper proposes the method to only detect the name text line among the whole overlay texts in one frame. The experimental results on Korean television news videos show that the proposed framework efficiently detects the overlaid name text line.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.307-318
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• 2016

비디오 프레임 내의 오버레이 텍스트는 음성과 시각적 내용에 부가적인 정보를 제공한다. 특히, 뉴스 비디오에서 이 텍스트는 비디오 영상 내용을 압축적이고 직접적인 설명을 한다. 그러므로 뉴스 비디오 색인 시스템을 만드는데 있어서 가장 신뢰할 수 있는 실마리이다. 텔레비전 뉴스 프로그램의 색인 시스템을 만들기 위해서는 텍스트를 검출하고 인식하는 것이 중요하다. 이 논문은 뉴스 비디오에서 오버레이 텍스트를 검출하고 인식하는데 도움이 되는 오버레이 텍스트 시작 프레임 식별을 제안한다. 비디오 시퀀스의 모든 프레임이 오버레이 텍스트를 포함하는 것이 아니기 때문에, 모든 프레임에서 오버레이 텍스트의 추출은 불필요하고 시간 낭비다. 그러므로 오버레이 텍스트를 포함하고 있는 프레임에만 초점을 맞춤으로써 오버레이 텍스트 검출의 정확도를 개선할 수 있다. 텍스트 시작 프레임 식별 방법에 대한 비교 실험을 뉴스 비디오에 대해서 실시하고, 적절한 처리 방법을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.190-192
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• 2012

In this paper, we present theoretical queuing analysis for hybrid overlay/underlay Cognitive Radio (CR) system by applying M/M/1 queuing model where the rate of arrival and the service capacity are subject to Poisson alterations. Numerical results are used to prove a high degree of accuracy for the derived expressions. The result can be used as a benchmark to evaluate the performance of a hybrid overlay/underlay CR system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8B
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• pp.539-546
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• 2007

For better performance and to avoid member service annoyance that results due to joining-clients' waiting durations and time-outs when there are more than one client wanting to join concurrently for Personal Broadcasting System service, there is a need for improving concurrent member joining mechanism. For a more efficient and better performing, this paper apply Overlay Multicast based mini-Overlay Broadcasting Control Protocol(mOBCP) Algorithm on Personal Broadcasting System. mOBCP proposed is performance-effective mechanism, since it considers the case of how fast will children, concurrently, find and join new parents when paths to existing parents are in Failure. The performance comparison, in terms of tree construction time variation and Latency are done through simulations and the results conclude in favour of the Proposed mOBCP.