• Title/Summary/Keyword: Sensing mechanism

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Performance of Spectrum Sensing Using AF Cooperative Relay for Cognitive Radio System (인지 무선 통신에서 AF 협력 릴레이를 이용한 스펙트럼 센싱 성능)

  • Lee, Mi-Sun;Kim, Yoon-Hyun;Kim, Jin-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.4
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    • pp.31-36
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    • 2012
  • In this paper, we proposed spectrum sensing using cooperative relay to solve problem of sensing performance degradation due to CPE (Customer-Premises equipments) which causes low SNR (signal-to-noise ratio) problem. In cooperative communication system, AF (amplify-and-forward) and DF (decoded-and-forward) is widely used for relay mechanism. Also, it is expected that cooperative relay scheme guarantees the high sensing performance by its diversity gain. Based on these backgrounds, in this paper, we apply to cooperative relay scheme to the CR (Cognitive Radio) system, and simulation results show comparison of the sensing performance.

Design and estimation of a sensing attitude algorithm for AUV self-rescue system

  • Yang, Yi-Ting;Shen, Sheng-Chih
    • Ocean Systems Engineering
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    • v.7 no.2
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    • pp.157-177
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    • 2017
  • This research is based on the concept of safety airbag to design a self-rescue system for the autonomous underwater vehicle (AUV) using micro inertial sensing module. To reduce the possibility of losing the underwater vehicle and the difficulty of searching and rescuing, when the AUV self-rescue system (ASRS) detects that the AUV is crashing or encountering a serious collision, it can pump carbon dioxide into the airbag immediately to make the vehicle surface. ASRS consists of 10-DOF sensing module, sensing attitude algorithm and air-pumping mechanism. The attitude sensing modules are a nine-axis micro-inertial sensor and a barometer. The sensing attitude algorithm is designed to estimate failure attitude of AUV properly using sensor calibration and extended Kalman filter (SCEKF), feature extraction and backpropagation network (BPN) classify. SCEKF is proposed to be used subsequently to calibrate and fuse the data from the micro-inertial sensors. Feature extraction and BPN training algorithms for classification are used to determine the activity malfunction of AUV. When the accident of AUV occurred, the ASRS will immediately be initiated; the airbag is soon filled, and the AUV will surface due to the buoyancy. In the future, ASRS will be developed successfully to solve the problems such as the high losing rate and the high difficulty of the rescuing mission of AUV.

Performance of Spectrum Sensing Using Cooperative Relay for Cognitive Radio System (인지 무선 통신을 위한 협력 릴레이 센싱 성능)

  • Lee, Mi-Sun;Kim, Yoon-Hyun;Kim, Jin-Young
    • Journal of Satellite, Information and Communications
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    • v.7 no.1
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    • pp.7-12
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    • 2012
  • In this paper, we proposed spectrum sensing using cooperative relay to solve problem of sensing performance degradation due to CPE (Customer-Primise equipments) which causes low SNR (signal-to-noise ratio) problem. In cooperative communication system, AF (amplify-and-forward) and DF (decoded-and-forward) is widely used for relay mechanism. Also, it is expected that cooperative relay scheme guarantees the high sensing performance by its diversity gain. Based on these backgrounds, in this paper, we apply to cooperative relay scheme to the CR (cognitive radio) system, and simulation results show comparison of the sensing performance between AF and DF.

A Study on the Suction Power Control of Vacuum Cleaner with a Dust Sensor (먼지센서에 의한 진공청소기의 흡입력 제어에 관한 연구)

  • 백승면;김성진;이만형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.304-307
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    • 1995
  • In this paper, an optical sensing system has been developed to detect the dust in vacuum cleaner. The system works well through self-tuning mechanism, even though there are systemic variance and characteristic change which is caused by the pollution on the surface of the optical elements. Using the developed sensing system, a novel suction power control system has been proposed, which is able to be used for a long time.

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A Space Charge Model for Semiconductor Gas Sensors (반도체 가스감지소자를 위한 공간전하 모델)

  • 이성필;이덕동;손병기
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.11
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    • pp.1631-1636
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    • 1989
  • A space charge model for semiconductor reduced gas sensors has been roposed and applied to gas sensing mechanism. SnO2-x and SnO2-x/Pt thin film were deposited by vacuum evaporating method. And Hall effect and gas sensitivity characteristics of these sensors were measured. From the space charge model and carrier concentration, the number of the adsorbed gas atom on the solid surface was calculated quantitatively. The gas sensing model was compared with CO gas sensitivities of the fabricated thin film gas sensors.

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Hot carrier effects on the performance degradation of sense amplifiers in DRAM (Hot carrier 현상에 의한 DRAM 감지증폭기의 성능저하)

  • 윤병오;장성준;유종근;정운달;박종태
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.433-436
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    • 1998
  • Hot carrier induceed the performance degradation of sense amplifier circuit in DRAM has been measured and analyzed using 0.8.mu.m CMOS process. Simulation and experimental results show that the degradation of the MOS devices affects the decrease of the half-Vcc, voltage gain and the increase of the sensing voltage gain and the increase of the sensing voltage. The dominant degradation mechanism is the capacitance imblance in the bit-line pair. We carried out the spice simulation to investigate the degradation of the sense amplifier circuit.

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Application of Frost Detecting Sensors in Refrigerators to Reduce Energy Consumption (냉장고 소비전력 저감을 위한 착상감지센서의 응용 연구)

  • 성창용;나승유;이희영
    • Proceedings of the IEEK Conference
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    • 2000.06e
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    • pp.147-150
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    • 2000
  • Manual and predictive defrosting method is used in current refrigerators, which have several problems in terms of energy consumption and efficiency. fuming the defrosting system on by the amount of frost remains to be an important problem which has to be improved by refrigerator manufacturers. The sensing of the amount of frost by FDS(Frost Detecting Sensor) and its proper mounting point are investigated in the paper. Also the realization of actual defrosting system through experiments of operation, energy consumption and sensing mechanism is presented.

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Quorum Sensing Regulation of Biofilm Formation by Periodontal Pathogens

  • Choi, Bong-Kyu
    • International Journal of Oral Biology
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    • v.43 no.4
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    • pp.171-175
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    • 2018
  • Quorum sensing (QS) is a cell density-dependent communication mechanism between bacteria through small signaling molecules. When the number of QS signaling molecules reaches a threshold, they are transported back into the cells or recognized by membrane-bound receptors, triggering gene expression which affects various phenotypes including bioluminescence, virulence, adhesion, and biofilm formation. These phenotypes are beneficial for bacterial survival in harsh environments. This review summarizes the application of QS inhibitors for control of biofilm formation and virulence expression of periodontal pathogens.