• Title/Summary/Keyword: IR transmission

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A Study on the LED-based Media Transmission Mechanics VLC System Module and Efficiency (LED 조명 기반 미디어 전송기법 가시광통신 시스템 모듈 설계 및 효율 연구)

  • Lee, Jun-myung;Kwon, Jae-hyun;Choi, Jung-won;Park, Keon-Jun
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.6 no.1
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    • pp.51-56
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    • 2013
  • In this paper, we had design the module of the LED-based media transmission mechanics visible light communication system. To implement the media transmission system through visible light communication transmitter, receiver module the using high brightness, we proposed visible light communication system to implement communication distance of up to a maximum transmitter-receiver distance using a variable PD sensor to the receiver and 1~12 the LED light-emitting device to the transmitter. It was increased efficiency of approximately 20% by measuring the performance during lens wearing or not wearing on the LED module to improve the efficiency of the media transmission system.

Transmission Characteristics of Indoor Infrared Diffuse Links Employing Three-Beam Optical Transmitters and Non-Imaging Receivers

  • Wang, Zan;Pan, Jae-Kyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12A
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    • pp.1251-1260
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    • 2008
  • Diffuse wireless optical communication offers more robust optical links in terms of coverage and shadowing than line-of-sight links. However, traditional diffuse wireless infrared (IR) transceiver systems are more susceptible to multi-path distortion and great power decrease, which results in limiting high-speed performance. Multi-beam is an effective technique to compensate for multi-path distortion in a wireless infrared environment. The goal of this paper is to analyze the transmission characteristics by replacing traditional diffuse system (TDS) which contains single wide angle transmitter and single element receiver by system consisting of three-beam transmitter and non-imaging receiver (TNS) attached with compound parabolic concentrator (CPC). In the simulation, we use the recursive model developed by Barry and Kahn and build the scenario based on 10 different cases which have been listed in Table 1. Moreover, we also check the reliability of the TNS diffuse link channel by BER test on the basis of different receiver positions and room sizes. The simulation results not only show the basic transmission characteristics of TNS diffuse link, but also are references to design more efficient and reliable indoor infrared transmission systems.

Studies on the Dwarf Disease of the Mulberry Tree(Transmission by Grafting and Insects) (뽕나무 위축병에 관한 연구(접목전염 및 곤충전염))

  • 장병호;김종진
    • Journal of Sericultural and Entomological Science
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    • v.13 no.1
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    • pp.17-22
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    • 1971
  • A series of experiments were conducted from 1968 to 1970 to find the transmission effects of the dwarf disease of mulberry tree in connection with inlay grafting and insect vector with the following conclusions: 1. The inlay-grafting of sound scions on diseased roots showed a 30 per cent transmission rate among the successful grafts. The inlay-grafting of diseased scions on sound roots showed a 14 per cent transmission rate among the successful grafts ir the case of scions cut and stored before wintering but no transmission effect in the case of scions prepared after wintering, There were some stocks, among the unsuccesful grasfts of diseased scions upon sound roots, that sprouted out new buds, no transmission effects were found in them, 2. Leafhoppers (Hishimonus disciguttus Walker) collected from areas with no dwarf disease infection were grouped into three plots and let to feed on mulberry tree severely infected by dwarf disease for 7 days, 14 days and 21 days respectively. After these preliminary treatment, the leafhoppers were recollected to be fed on the sound seedling divided into three plots for 10 days, 15 days and 20 days respectively to find the transmission effects. The results are that the 7 day plot showed no transmission effect whereas the 14 day plot showed a 22 per cent disease rate and the 21 day plot 61 per cent rate indicating that the longer the feeding period is the higher the transmission rate.

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A New Collision Paradigm in Impulse-Radio-based UWB Communications (IR-UWB 통신에서의 새로운 충돌 패러다임에 관한 연구)

  • Kang, Ji-Myung;Park, Young-Jin;Lee, Soon-Woo;Kim, Kwan-Ho;Kim, Moon-Hyun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.10
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    • pp.47-54
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    • 2007
  • Since impulse-radio-based ultra wideband (IR-UWB) do not use carrier frequency but use very short pulse to transmit data it sends data not continuously but discretely and this feature gives the potential to reduce collision in multi-user environment. In this paper, we analyse characteristic of IR-UWB and propose a new collision paradigm, Collision Distribution which changes collision level from packet to pulse. In Collision Distribution mechanical each node sends data with its own pulse interval in random time, distributed manner. It prevents packet drop due to packet collision. We show that Collision Distribution can reduce packet error and can provide real time packet transmission with analysis.

Microstructure Characterization for Nano-thick Ir-inserted Nickel Silicides (나노급 Ir 삽입 니켈실리사이드의 미세구조 분석)

  • Song, Oh-Sung;Yoon, Ki-Jeong;Lee, Tae-Hyun;Kim, Moon-Je
    • Korean Journal of Materials Research
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    • v.17 no.4
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    • pp.207-214
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    • 2007
  • We fabricated thermally-evaporated 10 -Ni/(poly)Si and 10 -Ni/1 -Ir/(poly)Si structures to investigate the microstructure of nickel monosilicide at the elevated temperatures required for annealing. Silicides underwent rapid at the temperatures of 300-1200 for 40 seconds. Silicides suitable for the salicide process formed on top of both the single crystal silicon actives and the polycrystalline silicon gates. A four-point tester was used to investigate the sheet resistances. A transmission electron microscope(TEM) and an Auger depth profile scope were employed for the determination of vertical section structure and thickness. Nickel silicides with iridium on single crystal silicon actives and polycrystalline silicon gates shoed low resistance up to 1000 and 800, respectively, while the conventional nickle monosilicide showed low resistance below 700. Through TEM analysis, we confirmed that a uniform, 20 -thick silicide layer formed on the single-crystal silicon substrate for the Ir-inserted case while a non-uniform, agglomerated layer was observed for the conventional nickel silicide. On the polycrystalline silicon substrate, we confirmed that the conventional nickel silicide showed a unique silicon-silicide mixing at the high silicidation temperature of 1000. Auger depth profile analysis also supports the presence of thismixed microstructure. Our result implies that our newly proposed iridium-added NiSi process may widen the thermal process window for the salicide process and be suitable for nano-thick silicides.

Performance Improvement of Downlink Real-Time Traffic Transmission Using MIMO-OFDMA Systems Based on Beamforming (Beamforming 기반 MIMO-OFDMA 시스템을 이용한 하향링크 실시간 트래픽 전송 성능 개선)

  • Yang Suck-Chel;Park Dae-Jin;Shin Yo-An
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.3 s.345
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    • pp.1-9
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    • 2006
  • In this paper, we propose a MIMO-OFDMA (Multi Input Multi Output-Orthogonal Frequency Division Multiple Access) system based on beamforming for performance improvement of downlink real-time traffic transmission in harsh channel conditions with low CIR (Carrier-to-Interference Ratio). In the proposed system, we first consider the M-GTA-SBA (Modified-Grouped Transmit Antenna-Simple Bit Allocation) using effective CSI (Channel State Information) calculation procedure based on spatial resource grouping, which is adequate for the combination of MRT (Maximum Ratio Transmission) in the transmitter and MRC (Maximum Ratio Combining) in the receiver. In addition, to reduce feedback information for the beamforming, we also apply QEGT (Quantized Equal Gain Transmission) based on quantization of amplitudes and phases of beam weights. Furthermore, considering multi-user environments, we propose the P-SRA (Proposed-Simple Resource Allocation) algorithm for fair and efficient resource allocation. Simulation results reveal that the proposed MIMO-OFDMA system achieves significant improvement of spectral efficiency in low CRI region as compared to a typical open-loop MIMO-OFDMA system using pseudo-orthogonal space time block code and H-ARQ IR (Hybrid-Automatic Repeat Request Incremental Redundancy).

Ultra-Wideband Microstrip-to-Finite Ground Coplanar Waveguide Transition for Millimeter-Wave Systems (밀리미터파 시스템용 초광대역 마이크로스트립-FGCPW 전이구조 설계)

  • Kim, Young-Gon;Kim, Hong-Rak;Jung, Bae-Ho;Kim, Kang Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.8
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    • pp.701-708
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    • 2016
  • A new design for an ultra-wideband microstrip-to-FGCPW(Finite Ground Coplanar Waveguide) transition is presented. The proposed transition provides the electric field and impedance matching between adjacent transmission lines by ground shaping. The transition is designed on the analytical expressions of whole transitional structure. Conformal mapping is applied to obtain the characteristic impedance of FGCPW with bottom aperture within 3.3 % accuracy as compared with the EM-simulation results. As design example, the fabricated transition in back-to-back configuration provides insertion loss less than 1 dB per transition and return loss better than 10 dB for frequencies from 9 GHz to over 40 GHz.

IR Signal Analysis and Band Selection for Two-color Seeker (Two-color 탐색기를 위한 적외선 신호 분석 및 대역 선정)

  • 오정수;서동선;최종수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.1B
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    • pp.112-119
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    • 2000
  • A two-color infrared (IR) seeker employs two detection-bands for efficient target tracking under countermeasures and background noises. This paper describes a study on the detection-band selections for the two-color seeker. To select the detection-bands, we analysis infrared radiation characteristics of a target, a flare, and background noises and then other characteristics closely related with the received power, such as the atmospheric transmission, acquisition range, background noise effect, and signal-to-noises. The analysis shows that the pertinent bands of two-color IR seeker are 3 um~5 um for target detection and 1.5 um~l.7 um for counter-countermeasures. The results of our study will play a significant role in the further study of two-color seekers.

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A Study on the MC-CDMA Using CMFB IIR Filter

  • Shin, Jonghong;Jang, Sunbong;Jee, InnHo
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.405-408
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    • 2002
  • Because of superior division among sub-channels, DWT MC-CDMA is less interference with neighborhood channel. In our newly proposed multi-carrier CDMA data transmission method, lIR CMFB filter banks sharply divide sub-bands and reduces spectral overlaps among neighboring sub-channels. In experiment result, proposed filter is better ability of sub-band division than FIR filter. Since the proposed cosine modulated filter banks lIR filter having wavelet property is designed to response sharp transition band, the ISI and ICI between neighboring sub-channels can be effectively reduced. And robustness about narrow band interference of CMFB IIR MC-CDMA almost same FIR DWT MC-CDMA.

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An efficient spatio-temporal index for spatio-temporal query in wireless sensor networks

  • Lee, Donhee;Yoon, Kyoungro
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.10
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    • pp.4908-4928
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    • 2017
  • Recent research into wireless sensor network (WSN)-related technology that senses various data has recognized the need for spatio-temporal queries for searching necessary data from wireless sensor nodes. Answers to the queries are transmitted from sensor nodes, and for the efficient transmission of the sensed data to the application server, research on index processing methods that increase accuracy while reducing the energy consumption in the node and minimizing query delays has been conducted extensively. Previous research has emphasized the importance of accuracy and energy efficiency of the sensor node's routing process. In this study, we propose an itinerary-based R-tree (IR-tree) to solve the existing problems of spatial query processing methods such as efficient processing and expansion of the query to the spatio-temporal domain.