• Title/Summary/Keyword: stream transmission

Search Result 376, Processing Time 0.024 seconds

Design and Implementation HDTV Relay Transmission System for Overlay Multicast (오버레이 멀티캐스트를 위한 HDTV 중계전송 시스템 설계 및 구현)

  • Son, Seung-Chul;Kwag, Yong-Wan;Heo, Kwon;Lee, Hyung-Ok;Nam, Ji-Seung
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.32 no.1A
    • /
    • pp.57-65
    • /
    • 2007
  • The overlay multicast that has been recently presented as IP alternative for the IP multicast has been getting much persuasion by the computing power of the hardware and the advancement of the network techniques to enforce Routing in application-level. In an overlay multicast, the system resource and the network bandwidth must be utilized efficiently to service real-time HDTV images. Specifically, the system must consider the delay and the jitter that can be incurred at the application-level. In this paper, we implement a server and a client to broadcast HDTV, in the session composed by the existing overlay multicast protocol. The broadcasting server performs the service using a TV tuner, An HDTV camcorder, and files, clients constituting a multicast group relay the received data to other clients. At this time, the information that the clients report periodically, including their delay and the network state, to the server is used as an important information to maintain an overlay session. The implementation is based on the DirectX and its performance is evaluated by the LAN test bed that has been set.

Design of Miniaturized Telemetry Module for Bi-Directional Wireless Endoscopy

  • Park, H. J.;H. W. Nam;B. S. Song;J. H. Cho
    • Proceedings of the IEEK Conference
    • /
    • 2002.07a
    • /
    • pp.494-496
    • /
    • 2002
  • A bi-directional and multi-channel wireless telemetry capsule, 11mm in diameter, is presented that can transmit video images from inside the human body and receive a control signal from an external control unit. The proposed telemetry capsule includes transmitting and receiving antennas, a demodulator, decoder, four LEDs, and CMOS image sensor, along with their driving circuits. The receiver demodulates the received signal radiated from the external control unit. Next, the decoder receives the stream of control signals and interprets five of the binary digits as an address code. Thereafter, the remaining signal is interpreted as four bits of binary data. Consequently, the proposed telemetry module can demodulate external signals so as to control the behavior of the camera and four LEDs during the transmission of video images. The proposed telemetry capsule can simultaneously transmit a video signal and receive a control signal determining the behavior of the capsule itself. As a result, the total power consumption of the telemetry capsule can be reduced by turning off the camera power during dead time and separately controlling the LEDs for proper illumination of the intestine.

  • PDF

Design of 1.5MHz Serial ATA Physical Layer (1.5MHz직렬 ATA 물리층 회로 설계)

  • 박상봉;신영호
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.2
    • /
    • pp.39-45
    • /
    • 2004
  • This paper describes the design and implementation of Serial ATA physical layer and performance measurement. It is composed of tranceiver circuit that has the NRZ data stream with +/-250㎷ voltage level and 1.5Gbps data rate, transmission PLL circuit, clock & data recovery circuit, serializer/deserializer circuit and OOB(Out Of Band) generation/detection circuit. We implement the verification of the silicon chip with 0.18{\mu}{\textrm}{m} Standard CMOS process. It can be seen that all of the blocks operate with no errors but the data transfer rate is limited to the 1.28Gbps even this should support 1.5Gbps data transfer rate.

Experimental Studies on the Motion and Discharge Behavior of Free Conducting Wire Particle in DC GIL

  • Wang, Jian;Wang, Zhiyuan;Ni, Xiaoru;Liu, Sihua
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.2
    • /
    • pp.858-864
    • /
    • 2017
  • This study aims to restrain free conducting wire-type particles which are commonly and dangerously existing within DC gas-insulated transmission lines. A realistic platform of a coaxial cylindrical electrode was established by using a high-speed camera and a partial discharge (PD) monitor to observe the motion, PD, and breakdown of these particles. The probabilities of standing or bouncing, which can be affected by the length of the particles, were also quantitatively examined. The corona images of the particles were recorded, and particle-triggered PD signals were monitored and extracted. Breakdown images were also obtained. The air-gap breakdown with the particles was subjected to mechanism analysis on the basis of stream theory. Results reveal that the lifting voltage of the wire particles is almost irrelevant to their length but is proportional to the square root of their radius. Short particles correspond to high bouncing probability. The intensity and frequency of PD and the micro-discharge gap increase as the length of the particles increases. The breakdown voltage decreases as the length of the particles decreases.

Distortion Measurement based Dynamic Packet Scheduling of Video Stream over IEEE 802.11e WLANs

  • Wu, Minghu;Chen, Rui;Zhou, Shangli;Zhu, Xiuchang
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.7 no.11
    • /
    • pp.2793-2803
    • /
    • 2013
  • In H.264, three different data partition types are used, which have unequal importance to the reconstructed video quality. To improve the performance of H.264 video streaming transmission over IEEE 802.11e Wireless Local Area Networks, a prioritization mechanism that categorizes different partition types to different priority classes according to the calculated distortion within one Group of Pictures. In the proposed scheme, video streams have been encoded based on the H.264 codec with its data partition enabled. The dynamic scheduling scheme based on Enhanced Distributed Channel Access has been configured to differentiate the data partitions according to their distortion impact and the queue utilization ratio. Simulation results show that the proposed scheme improves the received video quality by 1dB in PSNR compared with the existing Enhanced Distributed Channel Access static mapping scheme.

Quasi-quantitative estimation on backstreaming characteristics of a turbomolecular pump (터보분자펌프 역류특성의 준정량적 평가)

  • 인상렬;박미영
    • Journal of the Korean Vacuum Society
    • /
    • v.10 no.1
    • /
    • pp.1-9
    • /
    • 2001
  • Pumping characteristics of a turbomolecular pump are influenced by interrelations of the down-stream and upstream pumping speeds (transmission probabilityxaperture conductance), and of gas flow rates (pumping speedxentrance pressure) in two directions. The pumping speed, one of the most important items characterized the performance of a pump, is given by dividing the net flow rate, that is, the difference between the counter flow rates by the pressure at the pumping port. The maximum compression ratio is defined as the ratio of the downstream pumping speed to the upstream one. Because these directional characteristics affect each other and are functions of the pressures of both sides, it is difficult to distinguish the relevant factors. However, quasi-quantitative analyses on them can be done if considering carefully the results of measuring the pumping speed and the maximum compression ratio.

  • PDF

Multimedia Traffic Analysis using Markov Chain Model in CDMA Mobile Communication Systems (CDMA 이동통신 시스템에서 멀티미디어 트래픽에 대한 마르코프 체인 해석)

  • 김백현;김철순;곽경섭
    • Journal of Korea Multimedia Society
    • /
    • v.6 no.7
    • /
    • pp.1219-1230
    • /
    • 2003
  • We analyze an integrated voice/data CDMA system, where the whole channels are divided into voice prioritized channels and voice non-prioritized channels. For real-time voice service, a preemptivc priority is granted in the voice prioritized channels. And, for delay-tolerant data service, the employment of buffer is considered. On the other hand, the transmission permission probability in best-effort packet-data service is controlled by estimating the residual capacity available for users. We build a 2-dimensional markov chain about prioritized-voice and stream-data services and accomplish numerical analysis in combination with packet-data traffic based on residual capacity equation.

  • PDF

A Scheduling Algorithm of AP for Alleviating Unfairness Property of Upstream-Downstream TCP Flows in Wireless LAN (무선 랜에서의 상.하향 TCP 플로우 공평성 제고를 위한 AP의 스케쥴링 알고리즘 연구)

  • Lim, Do-Hyun;Seok, Seung-Joon
    • Journal of Korea Multimedia Society
    • /
    • v.12 no.11
    • /
    • pp.1521-1529
    • /
    • 2009
  • There is a serious unfairness problem between upstream and downstream flows of AP in IEEE 802.11 Wireless LAN. This problem is because Wireless LAN's DCF MAC protocol provides AP with equal channel access priority to mobile noded. Also, it makes this problem worse that the TCP's Data segment loss is more effective on throughput than the TCP's ACK segment. In this paper, we first make several simulations to analysis the unfairness in the various point of view and to find reasons of the unfairness. Also, this paper presents AP's scheduling scheme to alleviate the unfairness problem and evaluate the scheme through ns2 simulator.

  • PDF

Multimedia Stream Transmission Scheme using Parallel Server in Wireless and Mobile Environment (무선 모바일 환경에서 병렬서버를 사용한 멀티미디어 스트림 전송기법)

  • Heo, Joo;Jung, Jin-Ha;Woon, Wan-Oh;Shin, Kwang-Sik;Choi, Sang-Bang
    • Proceedings of the Korean Information Science Society Conference
    • /
    • 2003.10c
    • /
    • pp.7-9
    • /
    • 2003
  • 기존의 VOD 서비스는 일반적으로 단일 서버 모델을 사용하여 서비스 되어왔다. 그렇지만 단일 서버 모델의 VOD 서비스는 서버 용량의 확장에 따른 오버헤드가 크며 서버 고장시 VOD 서비스를 실시할 수 없는 문제점이 있다. 따라서 이런 문제점들을 해결하고자 병렬 서버 구조에 기반을 둔 VOD 서비스에 대한 연구가 이루어지고 있다. 기존의 유선 네트워크에서의 병렬 서버 구조에 기반을 둔 스트림 전송에 관한 연구가 일부 진행되어 왔지만 무선 네트워크와 관련해선 그러한 연구가 거의 없으며 있어도 아주 이상적인 경우를 가정하였다. 이동통신의 급속한 발전으로 현재 이동국들은 멀티미디어 서비스를 받을 수 있게 되었으며 앞으로는 이동국들에 제공되는 멀티미디어 서비스 역시 QoS가 보장되어야 한다. 따라서 본 논문에서는 무선 모바일 환경에서 병렬 서버 구조를 사용하여 멀티미디어 스트림을 전송함으로서 기지국외 혼잡 상황에도 이동국에서 QoS를 보장할 수 있는 방법을 제시한다. 시뮬레이션 분석 결과를 보면 기지국의 혼잡 상황에서 병렬 서버 구조에 기반을 두고 멀티미디어 스트림을 전송하게 되면 단일 서버로 멀티미디어 스트림을 전송할 때보다 이동국의 수신 상태가 42% 향상됨을 알 수 있다.

  • PDF

Searching for Change of Policing in Multicultural and Multiethnic Age (다인종.다문화 시대와 경찰활동 변화의 모색)

  • Lee, Hyo-Min
    • The Journal of the Korea Contents Association
    • /
    • v.7 no.9
    • /
    • pp.148-155
    • /
    • 2007
  • Meeting 21th century's globalization info-age, as well as material interchange between the country, comings and going of people and the stream of capital, the transmission of information are consisting vigorously. The interchange of Human and material, which pass over frontier, becomes important stepping-stone that can make run rich life to us. The interior of a country in staying foreigners are increasing. But, Actually Policing is short of police-educations and police-training. In accordance with in studies are check up point that policing for a change in foreigners for the sake.