• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.281-284
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• 2004

This paper described an Enhanced-xVSB system for improving mobile/pedestrian reception performance to the ATSC DTV 8-VSB transmission standard. E-xVSB system can transmit a mixture of normal (8-VSB) stream and enhanced (robust) stream. The robust stream has a higher threshold of visibility (TOV) compared to the standard stream, and legacy receivers ignore the robust packets. Thus, Enhanced-xVSB system is fully backward compatible with a current ATSC standard. for mobile and portable reception support, E-xVSB system adopts a reduced constellation method as well as enhanced trellis-coded modulation scheme. E-xVSB system supports a variety of enhanced modulation schemes: Pseudo-2VSB, Enhanced-4VSB, modified Enhanced-8VSB and Hybrid-VSB. Proposed E-xVSB system performs well under serious dynamic multipath reception environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10A
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• pp.951-961
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• 2002

In general, there is discontinuity phenomenon like a black screen and an irregular sound for repeated play of a finite digital stream. In this paper, for repeated play we analyze the relation between source and stream time causes this phenomenon. We obtain the time relation between video frame rate, audio frame rate, and TS packet transmission rate to eliminate this phenomenon. Using this time relation, we propose a new generation method of elementary stream (ES) and transport stream (TS) to eliminate discontinuity phenomenon. The test results of the generate ES and TS using the proposed method show that the discontinuity phenomenon can be eliminated for repeated play of a finite proposed stream.

• Journal of Korea Multimedia Society
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• v.4 no.4
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• pp.297-305
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• 2001

Recently advances in high-speed networks and multimedia computer technologies allow new types of multimedia applications to manipulate large volumes of multimedia data. However, in the real time and/or the heterogeneous data transmissions, there are many difficulties such as network transmission delay, the implementation difficulties, and so on. To solve these problems, in this paper, we extend the method of the multimedia service design which is proposed by OMG. To do this, we suggest an efficient real time audio/video stream framework, called Smart Explorer, based un CORBA and JMF Java Media API. And we separate the transmission path of control data from that of media data and use RTP/RTCP protocol for efficient real time audio/video transmission. Also we show the appropriate implementation of the audio/video stream system based on our suggested framework Smart Explorer. In the future, we expect our audio/video stream system to be applied to the real time communication software such as broadcasting, distance learning, and video conferencing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1112-1123
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• 2002

Providing a multimedia service requires efficient network bandwidth allocation scheduling. Typically, transmission of information with bursty characteristics, such as a video data stream, utilizes some type of smoothing technique that reduces the transmission rate fluctuation. While capable of a drastic reduction in the peak transmission rate, even the optimum smoothing algorithm proposed to date, however, is rather inadequate for multi-stream applications that share network bandwidth since such an algorithm has been designed and applied toward handling each independent stream. In this paper, we proposed an efficient bandwidth allocation algorithm that addresses these shortcomings. The proposed bandwidth allocation algorithm is divided into two steps, a static bandwidth allocation and a dynamic bandwidth allocation. In the former case, the peak rate reduction is achieved by maintaining the accumulated data in the user buffer at a high level, whereas the concept of real demand factor is employed to meet the needs of multi-stream bandwidth allocation in the latter case, Finally, the proposed algorithm's performance was verified with ExSpect 6.41, a Petri net simulation tool.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.304-309
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• 2004

Recently, the needs for multimedia stream such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic thorough the Internet, does not apply any congestion control mechanism to regulate the data flow thorough the shared network And it leads to congestion collapse of the Internet and results in long-term transmission delay. To avoid any adverse effect on the current Internet functionality, a now protocol of modification or addition of some functionality to perform congestion control and to reduce huge transmission delay in transmitting of multimedia stream are in study. TCP-friendly congestion control mechanism is classified into two : one is window-based congestion control scheme using general window management functionalities, the other is rate-based congestion control scheme using TCP modeling equation. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and late-based congestion control for multimedia stream. And we also simulate the performance of improved TEAR implementation using NS. With He simulation results, we show that the improved TEAR can provide better fairness and lower rate fluctuations than TCP.

• The Journal of Korean Institute for Practical Engineering Education
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• v.1 no.1
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• pp.51-54
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• 2009

In or automotive engineering education is introduced. Main objective of the system is teaching disassemble/assemble procedure of automatic transmission of a vehicle to students, who study automotive engineering. System includes vehicle transmission, set of tools and mechanical facilities, two video cameras, computer with developed software, HMD glasses and two LCD screens. Developed software gives instructions on assembling and disassembling processes of real vehicle transmission with the help of augmenting virtual reality objects on the video stream. Overlaying of 3D instructions on the technological workspace can be used as an interactive educational material. In disassembling process, mechanical parts which should be disassembled are augmented on video stream from video cameras. Same is done for assembling process. Animation and other visual effects are applied for better indication of the current assembling/disassembling instruction. During learning and training, student can see what parts of vehicle transmission and in which order should be assembled or disassembled. Required tools and technological operations are displayed to a student with the help of augmented reality, as well. As a result, the system guides a student step-by-step through an assembly/disassembly sequence. During educational process a student has an opportunity to return back to any previous instruction if it is necessary. Developed augmented reality system makes educational process more interesting and intuitive. Using of augmented reality system for engineering education in automotive technology makes learning process easier and financially more effective.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2922-2945
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• 2018

Achieving efficient authentication is a crucial issue for stream data commonly seen in content delivery, peer-to-peer, and multicast/broadcast networks. Stream authentication mechanisms need to be operated efficiently at both sender-side and receiver-side at the same time because of the properties of stream data such as real-time and delay-sensitivity. Until now, many stream authentication mechanisms have been proposed, but they are not efficient enough to be used in stream applications where the efficiency for sender and receiver sides are required simultaneously since most of them could achieve one of either sender-side and receiver-side efficiency. In this paper, we propose an efficient stream authentication mechanism, so called TIM, by integrating Trapdoor Hash Function and Merkle Hash Tree. Our construction can support efficient streaming data processing at both sender-side and receiver-side at the same time differently from previously proposed other schemes. Through theoretical and experimental analysis, we show that TIM can provide enhanced performance at both sender and receiver sides compared with existing mechanisms. Furthermore, TIM provides an important feature for streaming authentication, the resilience against transmission loss, since each data block can be verified with authentication information contained in itself.

• Journal of Broadcast Engineering
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• v.10 no.1 s.26
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• pp.14-21
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• 2005

This paper described an Enhanced-xVSB system for improving mobile/pedestrian reception performance to the ATSC(Advanced Television System Committee) DTV 8-VSB transmission standard. E-xVSB system can transmit a mixture of normal (8-VSB) stream and enhanced (robust) stream. The robust stream has a higher threshold of visibility (TOV) compared to the standard stream, and legacy receivers ignore the robust packets. Thus, Enhanced-xVSB system is fully backward compatible with a current ATSC standard. For mobile and portable reception support, E-xVSB system adopts a reduced constellation methodas well as enhanced trellis-coded modulation scheme. E-xVSB system supports a variety of enhanced modulation schemes : Pseudo-2VSB, Enhanced-4VSB, modified Enhanced-8VSB and Hybrid-VSB. Proposed E-xVSB system performs well under serious dynamic multipath reception environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1146-1158
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• 1993

In this paper, parallel scrambling techniques are considered for practical use in the SDH transmission and the ATM transmission. In the ATM transmission, there are two ways of transmitting ATM cells - the SDH-based and the cell-based - and the corresponding scrambling techniques differ accordingly. For the SDH transmission and the SDH-based ATM transmission, the FSS (frame synchronous scrambling) is applied to the STM frames : while for the cell-based ATM trans-mission, the DSS(distributed sample scrambling) is used on the ATM cell stream. The parallel scrambling techniques are examined for the FSS and the DSS, and applied to achieve the parallel FSSs for use in the SDH and the SDH-based ATM transmission along with the parallel DSS applicable to the cell-based ATM transmission. The resulting(8, 4) PSRG(parallel shift resister generator) and (8, 16) PSRG based parallel scramblings are directly applicable for the STM-1 rate processing of the STM-4 and STM-16 scramblings, respectively. Likewise, the resulting (1, 8)PSRG and double-sampling-double-correction based parallel scrambling techniques can be practically used for a low-rate processing of the SDH-based and the cell-based ATM signal scrambling respectively.

• International journal of advanced smart convergence
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• v.10 no.2
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• pp.59-63
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• 2021

In order to broadcast 8K UHD, domestic broadcasting is upgrading production, operation, and transmission technologies in a new way that has various forms such as terrestrial broadcasting, IPTV, mobile, and streaming services. In order to overcome the existing SDI transmission technology that has reached its limit, new transmission technologies using ICT-based convergence such as IT, Network, IOT, and Big Data are developing. Internet Protocol(IP) transmission technology is an IT-based core protocol that transcends various broadcasting infrastructures. Therefore, it can be said that the technology for converting the broadcasting system based on IP is a natural one for preparing for 8K UHD in the future. In this paper, we propose an IP transmission system that adopts a network that can transmit 8K with hardware of 12G Serial Digital Interface (SDI), in order to prepare for the future broadcasting system according to the development of ALL IP interface technology.