• 제목/요약/키워드: Sensing mechanism

검색결과 435건 처리시간 0.03초

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

  • 이미선;김윤현;김진영
    • 한국인터넷방송통신학회논문지
    • /
    • 제12권4호
    • /
    • pp.31-36
    • /
    • 2012
  • 본 논문에서는 인지무선통신에서 중요한 기술 중 하나인 스펙트럼 센싱의 Hidden node의 문제나 셀룰라 시스템에서 셀 경계에서 CPE(Customer Premises equipments)의 낮은 SNR(Signal to Noise Ratio)로 인한 센싱 성능 저하를 해결하기 위해 CPE들의 협력 릴레이 기법을 사용한 협력 스펙트럼 센싱을 제안하고 검출확률 성능을 분석한다. 송신단과 수신단 사이의 릴레이(Relay) 적용된 협력 스펙트럼 센싱은 가상의 공간 다이버시티이득(Spatial Diversity Gain)을 얻을 수 있어 센싱 성능이 향상된다. 협력 통신 기법 중 다중안테나를 적용한 AF(Amplify and Forward) 고정형 중계기를 사용하여 다이버시티이득을 얻는 시스템 모델을 제안하고, 검출 성능 향상을 분석한다.

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

  • Yang, Yi-Ting;Shen, Sheng-Chih
    • Ocean Systems Engineering
    • /
    • 제7권2호
    • /
    • pp.157-177
    • /
    • 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.

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

  • 이미선;김윤현;김진영
    • 한국위성정보통신학회논문지
    • /
    • 제7권1호
    • /
    • pp.7-12
    • /
    • 2012
  • 본 논문에서는 인지무선통신에서 중요한 기술 중 하나인 스펙트럼 센싱의 Hidden node의 문제나 셀룰라 시스템에서 셀 경계에서 CPE(Customer-Primise equipments)의 낮은 SNR(Signal to Noise Ratio)로 인한 센싱 성능 저하를 해결하기 위해 CPE들의 협력릴레이 기법을 사용한 협력 스펙트럼 센싱을 제안하고 검출확률 성능을 분석한다. 송신단과 수신단 사이의 릴레이(Relay) 적용된 협력 스펙트럼 센싱은 가상의 공간 다이버시티이득(Spatial Diversity Gain)을 얻을 수 있어 센싱 성능이 향상된다. 협력 통신 기법 중 AF(Amplify and Forward)와 DF(Decoded and Forward)방식이 대표적이다. 따라서 이 두가지 협력통신 기법을 적용하여 협력스펙트럼 센싱의 검출확률의 성능을 비교하고 분석한다.

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

  • 백승면;김성진;이만형
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 1995년도 추계학술대회 논문집
    • /
    • pp.304-307
    • /
    • 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.

  • PDF

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

  • 이성필;이덕동;손병기
    • 대한전자공학회논문지
    • /
    • 제26권11호
    • /
    • pp.1631-1636
    • /
    • 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.

  • PDF

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

  • 윤병오;장성준;유종근;정운달;박종태
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 1998년도 하계종합학술대회논문집
    • /
    • pp.433-436
    • /
    • 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.

  • PDF

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

  • 성창용;나승유;이희영
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
    • /
    • pp.147-150
    • /
    • 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.

  • PDF

Quorum Sensing Regulation of Biofilm Formation by Periodontal Pathogens

  • Choi, Bong-Kyu
    • International Journal of Oral Biology
    • /
    • 제43권4호
    • /
    • pp.171-175
    • /
    • 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.