• Title/Summary/Keyword: repetitive transmission

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Relay-based Cooperative Communication Technique using Repetitive Transmission on D-STBC (반복 전송을 이용한 D-STBC 중계기 협력 통신 기법)

  • Song, Ki-O;Jung, Yong-Min;Jung, Hyeok-Koo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.12A
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    • pp.1122-1127
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    • 2010
  • In this paper, we propose a relay-based DF cooperative communication scheme using repetitive transmission algorithm for wireless LAN environments on D-STBC. Additional transmission diversity gain can be obtained by repetitive transmission algorithm. However, in comparison with conventional schemes, data rate is decreased in half. We consider data modulation constellation twice higher than conventional schemes. Further, system complexity is decreased and performance degradation is minimized because repetitive transmission algorithm is adapted between source and relay node. We show the uncoded BER performance of the proposed algorithm over HiperLAN/2 Rayleigh fading channel.

A Case of Myasthenia Gravis Diagnosed by Repetitive Hypoglossal Nerve Stimulation Test (반복 설하신경 자극검사로 진단한 중증근무력증 1예)

  • Jang, Il-Mi;Lee, Kyung-Bok;Roh, Hakjae;Ahn, Moo-Young;Yang, Kwang-Ik;Sung, Ki-Bum
    • Annals of Clinical Neurophysiology
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    • v.8 no.1
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    • pp.74-77
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    • 2006
  • Repetitive nerve stimulation is a simple and widely used technique to demonstrate neuromuscular transmission defect. A significant decremental response for repetitive hypoglossal nerve stimulation was obtained from the surface recordings in the tongue of a patient with dysarthria and dysphagia. Repetitive hypoglossal nerve stimulation test may be useful in diagnosis of myasthenia gravis with bulbar symptoms only. We utilized repetitive hypoglossal nerve stimulation with tongue recordings and diagnosed a case of myasthenia gravis.

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A Study on the Data Frame Length and Repetitive Transmission for IP Local Broadcasting (인터넷 지역 방송에서 데이터 프레임 길이와 복수 전송에 관한 연구)

  • Oh, Jong-Taek
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.3
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    • pp.123-126
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    • 2011
  • As the number of users of smart phone and smart pad are increasing, the deployment of WiFi APs has been accelerated. Also Internet local broadcasting service will be activated near future. But transmission error is the critical problem, due to the one-way transmission of the data to the receivers. In this paper, FER is analysed according to BER and frame length, and repetitive transmission technique is proposed to reduce the effective FER.

A Study on the Effect of Redundant and Repetitive Transmission for Wireless Internet Local Broadcasting (무선 인터넷 지역 방송에서 복수전송과 재전송기술의 효과 연구)

  • Oh, Jong-Taek
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.12B
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    • pp.1468-1473
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    • 2011
  • With the proliferation of wireless LAN and smart phones, IP local broadcasting technology has been developed, and the new solution should be studied for error corrupted frames in the wireless broadcasting channel. In push service system using point-to-multi-point connection among broadcasting server and receivers, the technology proposed in this paper provides an effective data broadcasting system by employing frame length adjustment, redundant transmission, and repetitive transmission method.

Familial congenital myopathy with prominent decremental responses in repetitive nerve stimulation testing

  • Kim, Dayoung;Sunwoo, Il Nam;Oh, Jeeyoung
    • Annals of Clinical Neurophysiology
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    • v.23 no.1
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    • pp.53-55
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    • 2021
  • Congenital myasthenic syndromes (CMSs) are rare genetic disorders characterized by weakness and fatigue resulting from impaired neuromuscular transmission. Genetic testing can confirm the diagnosis for some types of CMS; however, variations in genotype, clinical phenotypes, age at disease onset, and responses to treatment make diagnosis very difficult. Here we present two adult patients who had significant decremental responses in repetitive nerve stimulation testing and multi-minicore pathology, and who responded to treatment with a cholinesterase inhibitor.

Tone-Based Access Scheme with Repetitive Contention in Contention-Based Medium Access Control (경쟁 기반 MAC에서의 반복적 톤 기반 경쟁 기법)

  • Ahn, Jae-Hyun;Yun, Jeong-Kyun;Bahk, Sae-Woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.5A
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    • pp.460-466
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    • 2007
  • There are two coordination functions in IEEE 802.11 standard. One is PCF, polling based function, and the other is DCF, contention based function. DCF is simpler than PCF but the performance is similar with the latter. That's the reason why DCF is more popular than PCF. However, DCF has a risk of collision with other nodes in the network because the function is a distributed contention based one. CSMA/CA of DCF has collision avoidance algorithm in it, but the performance of avoidance algorithm has limitations. In this paper we proposed a new scheme called TAR(Tone-based Access scheme with Repetitive conention). In TAR, there is narrow contention-only channel other than original data transmitting channel, so that both a data transmission and the contention can be performed simultaneously. The TAR uses the same contention concept with the CSMA/CA, but it has the originality for the narrow contention channel and the repetitive contention scheme which greatly reduce the collision probability. We proved the performance of TAR by some simulations, and it showed good results.

A study on performance enhancement of cyclic delay diversity OFDM system using frequency diversity (주파수 다이버시티를 이용한 순환 지연 다이버시티 OFDM 시스템의 성능 향상 연구)

  • Jung, Hyeok-Koo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.3A
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    • pp.135-140
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    • 2012
  • This paper proposes a technology for performance enhancement of cyclic delay diversity OFDM system using frequency diversity. The frequency diversity in an OFDM system can be done as repetitive transmission of the same symbol on uncorrelated subcarrier, this makes modulation level larger according to the number of repetitive transmission for the comparison with the traditional transmission system. This technique, like cyclic delay diversity, has a benefit which it does not need any special subsidiary hardware irrespective of the increase of the number of transmitter. For the performance comparison, we simulate the proposed algorithm in multiple input single out channel environment, it shows a better performance enhancement in low dense modulation level in comparison with the traditional cyclic delay diversity OFDM system.

Transient Coordinator: a Collision Resolution Algorithm for Asynchronous MAC Protocols in Wireless Sensor Networks

  • Lee, Sang Hoon;Park, Byung Joon;Choi, Lynn
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.12
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    • pp.3152-3165
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    • 2012
  • Wireless sensor networks (WSN) often employ asynchronous MAC scheduling, which allows each sensor node to wake up independently without synchronizing with its neighbor nodes. However, this asynchronous scheduling may not deal with collisions due to hidden terminals effectively. Although most of the existing asynchronous protocols exploit a random back-off technique to resolve collisions, the random back-off cannot secure a receiver from potentially repetitive collisions and may lead to a substantial increase in the packet latency. In this paper, we propose a new collision resolution algorithm called Transient Coordinator (TC) for asynchronous WSN MAC protocols. TC resolves a collision on demand by ordering senders' transmissions when a receiver detects a collision. To coordinate the transmission sequence both the receiver and the collided senders perform handshaking to collect the information and to derive a collision-free transmission sequence, which enables each sender to exclusively access the channel. According to the simulation results, our scheme can improve the average per-node throughput by up to 19.4% while it also reduces unnecessary energy consumption due to repetitive collisions by as much as 91.1% compared to the conventional asynchronous MAC protocols. This demonstrates that TC is more efficient in terms of performance, resource utilization, and energy compared to the random back-off scheme in dealing with collisions for asynchronous WSN MAC scheduling.

Development of Embedded Transmission Simulator for the Verification of Forklift Shift Control Algorithm (지게차 변속제어 알고리즘 검증을 위한 임베디드 변속기 시뮬레이터 개발)

  • Gyuhong Jung
    • Journal of Drive and Control
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    • v.20 no.4
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    • pp.17-26
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    • 2023
  • A forklift is an industrial vehicle that lifts or transports heavy objects using a hydraulically operated fork, and is equipped with an automatic transmission for the convenience of repetitive transportation, loading, and unloading work. The Transmission Control Unit (TCU) is a key component in charge of the shift control function of an automatic transmission. It consists of an electric circuit with an input/output signal interface function and firmware running on a microcontroller. To develop TCU firmware, the development process of shifting algorithm design, firmware programming, verification test, and performance improvement must be repeated. A simulator is a device that simulates a mechanical system having dynamic characteristics in real time and simulates various sensor signals installed in the system. The embedded transmission simulator is a simulator that is embedded in the TCU firmware. information related to the mechanical system that is necessary for TCU normal operation. In this study, an embedded transmission simulator applied to the originally developed forklift TCU firmware was designed and used to verify various forklift shift control algorithms.

Low Power Transmission Technique for Single-Carrier Modulation with Frequency Domain Equalization (주파수 영역 등화기를 사용하는 단일 반송파 전송 시스템을 위한 저 전력 전송 기법)

  • Jung, Hyeok Koo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.4
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    • pp.247-251
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    • 2017
  • This paper proposes a low power transmission technique for single-carrier modulation with frequency domain equalization. As time domain signals and frequency domain signals have unique corresponding functions, inserting zeros after each symbol causes a repetition in other domain, so maximal ratio combining technique using repetitive transmission can be applied in the frequency domain. In this paper, we configure transmit signals to insert zeros after each symbols for single-carrier modulation with frequency domain equalization and maximal ratio receive combining block in the receiver structures, propose a structure for transmitter and receiver and show that its performance is better than the traditional algorithm by simulations.