• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.3
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• pp.161-166
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• 2011

In this paper, for analysing the major factors giving the effect to the quality of HD level video on the multicasting service, we tried this test experiment on the College school network similar to the real service network environment. We measure the video quality distortion on the multicasting HD level video according to generating and increasing the broadcasting traffic on the situation that apply the QoS technique to the test network and not apply the QoS technique and then find out the threshold value of network factors giving the effect to the video quality distortion on the multicasting HD level video service. This paper can be used for guaranteeing the constant video quality and reducing the video quality distortion on the multicasting HD level video service.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.55-58
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• 2002

This paper describes an RF module for 2.4GHz wireless audio/video transmission. The pre-processed baseband input signals are FM-modulated using a VCO and then transmitted through an antenna after RF filtering. The designed circuits are implemented using a Teflon board of which the size is 52mm${\times}$62mm. The measured maximum output signal levels are around -3dBm and the harmonics are less than -450dBc. The manufactured module consumes 130mA from a 8V supply.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.225-228
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• 1988

A new transmission scheme is presented for transmitting motion video at very low data rates. In this scheme, two-level cartoons are extracted from gray-level images, and their interframe differences are coded using 2D run-length coding. Experimental results show that the proposed scheme yields compression ratio as high as 216:1.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.966-969
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• 2007

In this paper, we propose a novel probing mechanism for adaptive transmission of video data based on congestion control and client state. The proposed mechanism is friendly to the network dominant transport protocols (TCP) and can reduce fluctuations compared to the previous works.

• 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.

• Journal of Broadcast Engineering
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• v.14 no.1
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• pp.44-58
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• 2009

To provide efficient video streaming service over a wireless networks, the rate adaptation scheme should be applied at the low layer and the quality adaptation scheme should be considered at the high layer. In this paper, we propose a new cross-layer design which includes rate adaptation scheme at the MAC/PHY layers and quality control at the application layer. Proposed rate adaptation scheme improves the wireless channel utilization by transmitting the consecutive frames and selects optimal transmission mode by calculating the goodputs for each transmission mode. Based on selected transmission mode, the rate adaptation scheme calculates the rate limits and informs that to the application layer. Then the video streaming application utilizes this rate limits to adjust the quality of the video stream. Through performance evaluations, we prove that our cross-layer design improves the quality of the wireless video streaming service by means of the proposed rate adaptation scheme.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2080-2091
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• 1997

It is generally recognized that Video On Demand (VOD) service will become a promising interactive service in the emerging broadband integrated services digital networks. A centralized VOD system, all programs are stored in a single VOD server which is linked to each user via exchanges, is applicable when a small number of users enjoys the VOD service. However, in case of large service penetration, it is very important to solve the problems of bandwidth and load concentrating in the central video server(CVS) and program transmission network. In this paper, the architecture of the video distribution service network is studied, then a traffic characteristics and models for VOD system are established, and proposed program allocation method to video servers. For this purpose, we present an analysis of program storage amount in each LVS(Local Video Server), transmission traffic volume between LVSs, and link traffic volume between CVS and LVSs, according to changing the related factors such as demand, the number of LVS, vision probability, etc. A method for finding out storage capacity in LVSs is also presented on the basis of the tradeoffs among program storage cost, link traffic cost, and transmission cost.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.9-14
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• 2019

In modern society drones are actively utilized in the fields of security, defense, agriculture, communication and so on. Smart technology and artificial intelligence software have been developed with convergence, and the field of use is expected to expand further. On the point of the excellent performance of drones one of the essential technologies is the wireless communication that make the ground facility receive the video streaming obtained by the drones in the air. In the research the concept of communication region is proposed to cover the both the low altitude region for Wi-Fi communication and the high altitude region for LTE communication for the sake of video transmission. Also the hybrid communication structure is designed along the proposed concept and the proposed system is implemented as a communication system in the small size which can be mounted in a small size of drone. It is confirmed that the proposed system contains the effectiveness by showing the ability to successfully transmit HD video streaming in the range of 500 meters and the transfer time between two different communication systems is measured in 200msec by the experiments.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1995.06a
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• pp.97-100
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• 1995

In transmission of image sequences over ATM networks, the packet loss problem and channel sharing efficiency are important. As a possible solution two-layer video coding methods have been proposed. These methods transmit video information over the network with different levels of protection with respect to packets loss. In this paper, a two-layer coding method using pyramid structure is proposed and several realizations of two-layer video coding methods are presented and their performances are compared.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.435-446
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• 2014

Even if it is important to transmit high rate multimedia information without any transmission errors for surveillance systems, it is difficult to achieve error-free transmission due to infra-less adhoc networks. In order to reduce the transmission errors furthermore, additional signal overheads or retransmission of signals should be required, but they may lead to transmission delay. This paper represents a study on low delay and adaptive video transmission for the unmanned surveillance systems by developing system protocols. In addition, we introduce an efficient and adaptive control algorithm using system parameters for exploiting unmanned surveillance system properly over multi-channels.