• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.11-17
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• 2016

In this paper, we proposed a multi-viewer system with multiple HD cameras based AVB(Audio Video Bridge) ethernet cable using IP networking, and FPGA(Xilinx Zynq 702) for bus safety systems. This AVB (IEEE802.1BA) system can be designed for the low latency based on FPGA, and transmit real-time with HD video and audio signals in a vehicle network. The proposed multi-viewer platform can multiplex H.264 video signals from 4 wide-angle HD cameras with existed ethernet 1Gbps. and 2-wire 100Mbps cables. The design of Zynq 702 based low latency to H.264 AVC CODEC was proposed for the minimization of time-delay in the HD video transmission of car area network, too. And the performance of PSNR(Peak Signal-to-noise-ratio) was analyzed with the reference model JM for encoding and decoding results in H.264 AVC CODEC. These PSNR values can be confirmed according the theoretical and HW result from the signal of H.264 AVC CODEC based on Zynq 702 the multi-viewer with multiple cameras. As a result, proposed AVB multi-viewer platform with multiple cameras can be used for the surveillance of audio and video around a bus for the safety due to the low latency of H.264 AVC CODEC design.

• Journal of Ubiquitous Convergence Technology
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• v.2 no.2
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• pp.88-96
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• 2008

IPTV Content delivery systems over wired networks confront scalability problems due to their high network bandwidth requirement for real-time services. Especially, VoD service provides Trick Mode features such as pause, fast forward and similar operations. However, Trick Mode services are delivered by the method of unicast only for controlling of the stream. With a point of views, this paper propose a new real-time multimedia streaming architecture over IP Networks, which tries to achieve bandwidth efficiency and supporting for mass clients better than traditional unicast services. The proposed methods divide the Transport Stream into a series of segments. After that, this divided partial Transport Stream makes multicast streaming periodically. Meanwhile Set-top Box of a client makes a rearrangement orderly by using Presentation Time Stamp field from the served Transport Stream packets. While the current Transport Stream segment is playing, it should be guaranteed that the next segment is downloaded on time. Consequently, the original video content can be played out continuously. The detail introduction of a new real-time multimedia streaming system with analysis and simulation follows as below.

• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.67-77
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• 1998

In this paper we describe a development of a multi user game using 3D graphics and multicasting. First, we represent a virtual reality world by 3D graphics technology. Next, we use computer communication technology for the purpose of interaction among multi users. As a result, multi users share 3D graphics objects and play games. The goal of this paper is a development of a system that enables multi users to play games sharing a virtual world represented by 3D graphics. We use the OpenInventor library and C++ language for 3D graphics scene representation, and IP multicasting protocols for computer communication. The system allows to use Polhemus Fastrak 3D input device that recognizes the 3D position and 3D orientation. As an example we present a game that demonstrates the effect of piano concert by multi piano players who are distributed in a computer network.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.231-236
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• 2003

Video conferencing system it is various at internet and uses the reading is become accomplished. Research of like this portion synchronization of audio, the video compression technique and multimedia data, supports the video conference the research of the Mbone of the If multicast for being active, being become accomplished the multimedia service which is various an video from internet, the line speed of communication becomes high-speed anger and to follow leads is become accomplished. The video conference from opening elder brother dispersion internet network environment the problem against the image which is an image conference data and a voice security is serious and it raises its head. To sleep it presents the security method which from the video conference it follows in quality of multimedia data from the dissertation which it sees and it does.

• Korean Journal of Digital Imaging in Medicine
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• v.6 no.1
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• pp.51-64
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• 2003

This thesis describes the effective interfacing methods of PACS Modality based on the system installation andoperating experiences. PACS(Picture Archiving and Communication Systems) is a system for medical image archiving and communication using large storage device and high-speed network. The standard communication protocol of PACS is DICOM(Digital Imaging and Communication in Medicine) based on TCP/IP and point-to-point protocol. However, there are many Non-DICOM Modalities and DICOM Modalities having problems. First, we had interfaced almost modalities. Fuji CR, GE CT, MRI, Angio, Fluoro, Phillips Angio, Shimadzu Fluoro. Ultrasound PACS, with the main PACS in the Seoul S Hospital as large scale hospital. And we manipulated the intelligent image distribution and the CT. MRI Interfaces never experienced beforein the Anyang J Hospital and the Chungju C Hospital as mid or small scale hospital. Technically, we developed both the DICOM Interface and the Non-DICOM Interface. At the last, the DICOM Worklist and the DICOM Print Interface were implemented in the Seoul B Hospital, the Bucheon SJ Hospital and the Seoul K Hospital independently with PACS. The Oracle, Sybase and MS-SQL are used as database, and UNIX, Macintosh, MS Windows as operating systems. And the Visual C++ and UNIX C are the main programming tools. We have used UTP, coaxial and fiber optic cable under 10/100 mbps LAN for networking.

• Korean Journal of Digital Imaging in Medicine
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• v.5 no.1
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• pp.46-63
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• 2002

This thesis describes the effective interfacing methods of PACS Modality based on the system installation and operating experiences. PACS(Picture Archiving and Communication Systems) is a system for medical image archiving and communication using large storage device and high-speed network. The standard communication protocol of PACS is DICOM(Digital Imaging and Communication in Medicine) based on TCP/IP and point-to-point protocol. However, there are many Non-DICOM Modalities and DICOM Modalities having problems. First, we had interfaced almost modalities, Fuji CR, GE CT, MRI, Angio, Fluoro, Phillips Angio, Shimadzu Fluoro, Ultrasound PACS, with the main PACS in the Seoul S Hospital as large scale hospital. And we manipulated the intelligent image distribution and the CT, MRI Interfaces never experienced before in the Anyang J Hospital and the Chungju C Hospital as mid or small scale hospital. Technically, we developed both the DICOM Interface and the Non-DICOM Interface. At the last, the DICOM Worklist and the DICOM Print Interface were implemented in the Seoul B Hospital, the Bucheon SJ Hospital and the Seoul K Hospital independently with PACS. The Oracle, Sybase and MS-SQL are used as database, and UNIX, Macintosh, MS Windows as operating systems. And the Visual C++ and UNIX C are the main programming tools. We have used UTP, coaxial and fiber optic Gable under 10/100 mbps LAN for networking.

• Journal of IKEEE
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• v.9 no.2 s.17
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• pp.170-178
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• 2005

The video data corrupted by the transmission error due to packet loss induce error propagation in decoded video data, and cause poor video quality. To remedy these corrupted video data, there have been introduced two types of error concealment techniques: spatial or temporal error concealment algorithm. Computational overhead by using spatial error concealment algorithm is a serious disadvantage in mobile video data streaming environment. In this paper, we propose hybrid type error concealment technique recovering video quality of mobile device using MPEG-4 video streaming on error-prone wireless network. Our algorithm is implemented in MPEG-4 decoder. The algorithm adopts Intel Wireless MMX technology to provide high performance of portable embedded multimedia mobile device. It is proven that the proposed algorithm shows expected performance for a mobile streaming system(PDA) on IP channels. Our approach showed better processing speed and better video quality comparing with traditional error concealment algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12B
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• pp.1049-1057
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• 2006

Overlay Multicast is an effective method for efficient utilization of system resources and network bandwidth without using hardware customization. Unlike in IP multicast, multicast tree reconstruction is required when non-leaf node leaves or fails. In this paper, we propose a proactive approach to solve this defect by using a resource reservation of the out degrees. This allows children of non-leaf node to connect to its new parent node immediately when its parent node leaves or fails. In our proposal, a proactive route maintenance gives a fast recovery time and reduces a delay effect in the new route. The simulation results show that our proposal takes shorter period of time than the other algorithms to reconstruct a similar tree and that it is a more effective way to deal with a lot of nodes that have lost their parent nodes.

• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.95-104
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• 2013

DDoS attacks have became as a social threat since 2009 7.7 DDoS turmoil. Even though defence techniques have been developing to provide against those threats, they become much more sophisticate. In recent years, the attack form of DDoS is changing from high amount of traffic attack of network layers to highly sophisticate small amount of application layers. To make matters worse, attack agent for the attack has became very intelligent so that it is difficult to be blocked since it can't be distinguished from normal PCs. In the user authentication system(such as CAPTCHA) User intervention is required to distinguish normal PCs and intelligent attack agents and in particular, in a NAT environment, IP-based blocking method can be cut off the normal users traffic at the same time. This research examined defense techniques which are able to distinguish between agent and normal PC and effectively block ways the HTTP DDoS offense applying one-time session key based authentication method using Cookie which is used in HTTP protocol to protect web sever from sophisticate application layer of DDoS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1525-1530
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• 2022

BGP(Border Gateway Protocol) is a routing protocol that is actively used in inter-AS routing on the Internet. However, BGP routing protocol is vulnerable to BGP hijacking attacks that hijack the network by impersonating normal BGP sessions. BGP Hijacking attacks can lead to causing intercept IP traffic or interference with the normal service operation. Recently, BGP hijacking attacks, which have often occurred overseas, have also occurred in Korea. It means threatening the security of the Internet. In this paper, we analyze the overall process of attack through representative attack cases and virtual scenarios of BGP hijacking and based on the results of analyzing the application status of security technology to prevent BGP hijacking attacks by Korea and global major ISPs. It covers the technical proposal of ISPs and autonomous system operators should take to defend against BGP hijacking attacks.