• 조명전기설비학회논문지
• /
• 제23권6호
• /
• pp.31-39
• /
• 2009

본 논문은 기존의 자동문시스템의 단점을 개선하여 보다 지능적인 기능을 추가함으로써 통행자에게 편의를 제공하고, 전격손실을 낮추는 보다 효율적인 초음파센서 기반의 지능형 자동문 시스템을 제안한다. 기존의 자동문시스템에서는 물체 및 인체 감지 기능 센서로서 원적외선 열선 감지센서와 근적외선 반사식 감지센서를 사용해 왔나. 기존의 방식은 상황에 맞지 않는 문닫힘에 의한 전력손실, 빠르게 다가오는 물체에 대한 적응 부족, 그리고 안전에 대한 문제점이 있었다. 제안된 초음파센서를 이용한 지능형자동문 시스템은 기존의 자동문시스템에 비교하여 필요없는 문닫힘 방지에 의한 전력손실 방지와 빠르게 접근하는 물체에 적응적으로 자동문이 빠르게 열릴 수 있게 하며, 안전도를 높여 기존 방식의 자동문보다 운용적, 경제적, 안정 면에서 성능을 개선하였다.

• 한국음향학회지
• /
• 제36권1호
• /
• pp.30-38
• /
• 2017

본 논문에서는 수동 소나 시스템을 위한 수중 음향 센서 결함 탐지 기법을 제안하였다. 일반적으로 수동 소나 시스템에서는 수십개의 음향 센서를 통해 얻은 음향 신호를 이용하여 배열 신호처리 기법을 이용해 처리된 신호를 협대역 또는 광대역 분석을 위한 2차원 영상 형태로 전시한다. 운용 소프트웨어에서 전시되는 탐지 결과는 배열 신호처리를 통해 누적된 결과값을 전시하기 때문에, 단일 센서 채널의 결함 또는 고장에 따른 신호의 이상 여부를 판단하는데 어려움이 있다. 따라서 본 논문에서는 인접 채널간 실효치 비교 및 실효치교차율(Root Mean Square Crossing-Rate, RMSCR) 분석기반 센서 자동 결함 탐지 기법을 제안하고, 결함 센서 채널에 대한 처리 기법을 비교 분석하였다. 제안된 기법의 성능 분석을 위하여 일부 연안 지역에서 실제 운용 중인 센서 배열을 통해 획득된 신호를 이용하여 결함 탐지 정확도를 측정하고, 결함 처리 기법의 성능을 비교하였다. 실험을 통해 제안된 기법이 높은 RMS의 주변소음 환경에서도 높은 결함 탐지 정확도를 보였으며, 결함 처리 기법으로는 0으로 설정 처리 기법이 가장 높은 성능을 보였다.

• 센서학회지
• /
• 제23권4호
• /
• pp.238-244
• /
• 2014

In this paper, we introduce a new passive transponder that operates without external power in a visible light identification system. The transponder consists of a solar cell, a photodiode, a microprocessor, and a visible LED. When a reader sends light to the transponder, the solar cell generates current from the reader light and supplies power to the other elements in the transponder. At the same time, the photodiode detects the pulse in the reader light and initiates a microprocessor to generate and send a responding light to the reader. In experiments, we realized a passive transponder using a solar cell that operated at a distance of 1m without external power.

• 한국군사과학기술학회지
• /
• 제18권5호
• /
• pp.538-547
• /
• 2015

The goal of this study is to develop an algorithm to propose optimal deployment of detection sensor nodes in the target area, based on a performance surface, which represents detection performance of active and passive acoustic sonar systems. The performance surface of the active detection system is calculated from the azimuthal average of maximum detection ranges, which is estimated with a transmission loss and a reverberation level predicted using ray-based theories. The performance surface of the passive system is calculated using the transmission loss model based on a parabolic equation. The optimization of deployment configurations is then performed by a hybrid method of a virtual force algorithm and a particle swarm optimization. Finally, the effectiveness of deployment configurations is analyzed and discussed with the simulation results obtained using the algorithm proposed in this paper.

• 한국대기환경학회지
• /
• 제28권2호
• /
• pp.159-171
• /
• 2012

Aerosol direct radiative forcing (ADRF) retrieval method was developed by combining data from passive and active satellite sensors. Aerosol optical thickness (AOT) retrieved form the Moderate Resolution Imaging Spectroradiometer (MODIS) as a passive visible sensor and aerosol vertical profile from to the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) as an active laser sensor were investigated an application possibility. Especially, space-born Light Detection and Ranging (Lidar) observation provides a specific knowledge of the optical properties of atmospheric aerosols with spatial, temporal, vertical, and spectral resolutions. On the basis of extensive radiative transfer modeling, it is demonstrated that the use of the aerosol vertical profiles is sensitive to the estimation of ADRF. Throughout the investigation of relationship between aerosol height and ADRF, mean change rates of ADRF per increasing of 1 km aerosol height are smaller at surface than top-of-atmosphere (TOA). As a case study, satellite data for the Asian dust day of March 31, 2007 were used to estimate ADRF. Resulting ADRF values were compared with those retrieved independently from MODIS only data. The absolute difference values are 1.27% at surface level and 4.73% at top of atmosphere (TOA).

• 전기학회논문지
• /
• 제67권2호
• /
• pp.314-324
• /
• 2018

This paper proposes a linear distributed target tracking filter for multiple unmanned aerial vehicles(UAVs) sharing their passive sensor measurements through communication channels. Different from the conventional nonlinear filtering schemes, the distributed passive target tracking problem is newly formulated within the framework of a linear robust state estimation theory incorporated with a linear uncertain measurement equation including the coordinate transform uncertainty. To effectively cope with the performance degradation due to the coordinate transform uncertainty, a linear consistent robust Kalman filter(CRKF) theory is devised and applied for designing a distributed passive target tracking filter. Through the simulations for typical UAV surveillance mission, the superior performance of the proposed method over the existing schemes of distributed passive target tracking are demonstrated.

• PNF and Movement
• /
• 제20권2호
• /
• pp.215-222
• /
• 2022

Purpose: The purpose of this study was to compare the effects of passive scapular upward rotation and posterior tilt and active scapular posterior tilt on the muscle activity of the upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA). Methods: Fifteen healthy subjects performed general arm elevation, arm elevation with passive scapular upward rotation and posterior tilt, and arm elevation with active scapular posterior tilt. For active scapular posterior tilt, the subjects were trained in this movement using visual biofeedback and a motion sensor. During each arm elevation condition, electromyography was used to measure the muscle activity of the UT, LT, and SA. The measured data were analyzed using a one-way repeated ANOVA. Results: LT muscle activity was significantly increased during arm elevation with active scapular posterior tilt compared to both general arm elevation and arm elevation with passive scapular upward rotation and posterior tilt (p < 0.05). SA muscle activity was greater during arm elevation with passive scapular upward rotation and posterior tilt than during general arm elevation (p < 0.05). There was no significant change in UT muscle activity among the tested arm elevation conditions (p > 0.05). Conclusion: Performing arm elevation with active scapular posterior tilt and performing arm elevation with passive scapular upward rotation and posterior tilt may be useful strategies for increasing muscle activation of the LT and SA, respectively.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
• /
• pp.159-162
• /
• 2002

We introduce a simple optically passive detection scheme for Bragg grating sensors. This detection scheme is based on two cavity lengths in Fabry-Perot read-out interferometers to produce two quadrature phase shifted signals from the Bragg grating sensor. The passive detection technique is demonstrated by the use of Bragg grating sensors in measuring the dynamic vibrations of the composites.

• Smart Structures and Systems
• /
• 제4권5호
• /
• pp.531-548
• /
• 2008

Recently, dense sensor instrumentation for structural health monitoring has motivated the need for novel passive wireless sensors that do not require a portable power source, such as batteries. Using a layer-by-layer self-assembly process, nano-structured multifunctional carbon nanotube-based thin film sensors of controlled morphology are fabricated. Through judicious selection of polyelectrolytic constituents, specific sensing transduction mechanisms can be encoded within these homogenous thin films. In this study, the thin films are specifically designed to change electrical properties to strain and pH stimulus. Validation of wireless communications is performed using traditional magnetic coil antennas of various turns for passive RFID (radio frequency identification) applications. Preliminary experimental results shown in this study have identified characteristic frequency and bandwidth changes in tandem with varying strain and pH, respectively. Finally, ongoing research is presented on the use of gold nanocolloids and carbon nanotubes during layer-by-layer assembly to fabricate highly conductive coil antennas for wireless communications.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2011년도 춘계학술대회
• /
• pp.777-778
• /
• 2011

본 논문에서는 높은 신뢰성과 긴 수명을 특징으로 하는 저가형 센서로 마그네틱 픽업코일 방식의 자기유도작용을 이용한 수동형 차륜 속도센서를 제작하여 그 특성을 분석하였다. 제작된 수동형 차륜 속도센서는 직접적인 유도 기전력을 감지하여 유도하는 Pole piece, 영구자석과 Bobbin역할을 하는 내피와 코일로 구성된 센서부, 세서를 보호하고 외부 노이즈를 제거하는 외피부, 그리고 센서를 보강 및 고정하기 위한 플랜지부로 구성된다. 제작된 센서를 기성품과 특성을 비교, 분석하였다.