• 전기학회논문지
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• 제57권1호
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• pp.92-97
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• 2008

This is a research to apply 1310nm single-mode optical fiber to a temperature sensor. The existing study of optical fiber sensor is complicated because it was made with various equipment. To vary scattering, the variation of optical frequency is measured by using Bragg(lattice) or pulse generator and also bulk system is created by YAG laser but there were some difficulties creating experimental environment and it was a problem that the stability of measured data was low. The temperature sensor system using the suggested sBs(stimulated Brillouin scattering:sBs) from this research is much more simplified straight-line system. To improve the trust and accuracy of noises from optical frequency and unclear results, it was analysed by using Neuro-Fuzzy algorithm. we tried to get more correct data than existing system. sBs measure that optical frequency changed due to the variation of temperature. The analyzed change rate of outcome by Fuzzy theory is 1.1 MHz.

• 센서학회지
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• 제27권5호
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• pp.328-334
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• 2018

The paper reviews an improved continuous-wave (CW) terahertz (THz) imaging system developed for nondestructive inspection, such as CW-THz quasi-time-domain spectroscopy (QTDS) and interferometry. First, a comparison between CW and pulsed THz imaging systems is reported. The CW-THz imaging system is a simple, fast, compact, and relatively low-cost system. However, it only provides intensity data, without depth and frequency- or time-domain information. The pulsed THz imaging system yields a broader range of information, but it is expensive because of the femtosecond laser. Recently, to overcome the drawbacks of CW-THz imaging systems, many studies have been conducted, including a study on the QTDS system. In this system, an optical delay line is added to the optical arm leading to the detector. Another system studied is a CW-THz interferometric imaging system, which combines the CW-THz imaging system and far-infrared interferometer system. These systems commonly obtain depth information despite the CW-THz system. Reportedly, these systems can be successfully applied to fields where pulsed THz is used. Lastly, the applicability of these systems for nondestructive inspection was confirmed.

• 센서학회지
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• 제10권3호
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• pp.163-172
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• 2001

넓은 지역에 걸친 침입자의 침투를 감시하기 위하여 수십 km의 광섬유 길이 전체를 감지부로 사용할 수 있는 광섬유 BOTDA (Brillouin Optical Time Domain Analysis) 센서를 개발하였다. 광섬유 BOTDA 센서는 한 개의 레이저 다이오드와 두 개의 광전 변조기(electro-optic modulator)를 사용하여 간단하게 구성하였다. 침입자에 의한 광섬유의 변형률 변화를 탐지하는 실험을 수행하기 위하여 광학테이블 위에 광섬유에 변형률을 인가하기 위한 실험장치를 설치하여 실험을 수행하였다. 이 실험으로부터 시간간격 1.5 초동안 광섬유 약 4.81 km의 길이를 거리분해능 3 m로 침입자를 탐지할 수 있음을 확인하였다.

• 센서학회지
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• 제7권6호
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• pp.432-436
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• 1998

최근에 액정을 이용한 대형 디스플레이 장치를 만들기 위하여 PDLC(Polymer Dispersed Liquid Crystal)가 활발하게 개발되고 있다. 이것은 광손실이 적고 휘도가 높으며 제작 공정이 간단하여, 대형 디스플레이 장치로 제작하기 쉽다. 본 연구에서는 PDLC의 전기광학적 특성을 알아보기 위해 응답속도와 인가전압에 따른 광투과량을 측정하였다. 측정방법은 He-Ne 레이저를 PDLC 셀에 조사하고, 투과된 광량은 광다이오드를 사용하여 측정하였다. 측정결과는 디지털 오실로스코프로 분석하고 그래픽으로 표시하였으며, 측정한 데이터를 가지고 기존의 LCD와 비교하여 디스플레이 장치로서의 가능성을 연구하였다.

• Smart Structures and Systems
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• 제19권6호
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• pp.679-694
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• 2017

The complexity, enlargement and irregularity of structures and multi-directional dynamic loads acting on the structures can lead to unexpected structural behavior, such as torsion. Continuous torsion of the structure causes unexpected changes in the structure's stress distribution, reduces the performance of the structural members, and shortens the structure's lifespan. Therefore, a method of monitoring the torsional behavior is required to ensure structural safety. Structural torsion typically occurs accompanied by displacement, but no model has yet been developed to measure this type of structural response. This research proposes a model for measuring dynamic torsional response of structure accompanied by displacement and for identifying the torsional modal parameter using vision-based displacement measurement equipment, a motion capture system (MCS). In the present model, dynamic torsional responses including pure rotation and translation displacements are measured and used to calculate the torsional angle and displacements. To apply the proposed model, vibration tests for a shear-type structure were performed. The torsional responses were obtained from measured dynamic displacements. The torsional angle and displacements obtained by the proposed model using MCS were compared with the torsional response measured using laser displacement sensors (LDSs), which have been widely used for displacement measurement. In addition, torsional modal parameters were obtained using the dynamic torsional angle and displacements obtained from the tests.

• 로봇학회논문지
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• 제7권2호
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• pp.92-100
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• 2012

A map of complex environment can be generated using a robot carrying sensors. However, representation of environments directly using the integration of sensor data tells only spatial existence. In order to execute high-level applications, robots need semantic knowledge of the environments. This research investigates the design of a system for recognizing objects in 3D point clouds of urban environments. The proposed system is decomposed into five steps: sequential LIDAR scan, point classification, ground detection and elimination, segmentation, and object classification. This method could classify the various objects in urban environment, such as cars, trees, buildings, posts, etc. The simple methods minimizing time-consuming process are developed to guarantee real-time performance and to perform data classification on-the-fly as data is being acquired. To evaluate performance of the proposed methods, computation time and recognition rate are analyzed. Experimental results demonstrate that the proposed algorithm has efficiency in fast understanding the semantic knowledge of a dynamic urban environment.

• Journal of Astronomy and Space Sciences
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• 제26권4호
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• pp.643-650
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• 2009

Korea Astronomy and Space Science Institute (KASI) has been developing one mobile and one stationary SLR system since 2008 named as ARGO-M and ARGO-F, respectively. KASI finished the step of deriving the system requirements of ARGO. The requirements include definitions and scopes of various software and hardware components which are necessary for developing the ARGO-M operation system. And the requirements define function, performance, and interface requirements. The operation system consisting of ARGO-M site, ARGO-F site, and Remote Operation Center (ROC) inside KASI is designed for remote access and the automatic tracking and control system which are the main operation concept of ARGO system. To accomplish remote operation, we are considering remote access to ARGO-F and ARGO-M from ROC. The mobile-phone service allows us to access the ARGO-F remotely and to control the system in an emergency. To implement fully automatic tracking and control function in ARGO-F, we have investigated and described the requirements about the automatic aircraft detection system and the various meteorological sensors. This paper addresses the requirements of ARGO Operation System.

• 한국정보통신학회논문지
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• 제8권5호
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• pp.1074-1079
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• 2004

지금까지 3차원 정보를 얻기 위하여 CCD카메라, 레이저, 구조화된 격자 발생기 등과 같은 여러 센서들이 사용되어져 왔지만 대부분의 캘리브레이션 알고리즘들은 많은 메모리와 실험 시간을 필요로 하기 때문에 비효율적이었다. 본 논문에서는 실세계 상의 3차원 정보를 얻기 위한 삼각법을 기반으로한 구조화된 격자 캘리브레이션 알고리즘이 소개된다. CCD카메라와 수평으로 설치된 구조화된 격자 패턴 생성기로부터 생성된 빔들이 캘리브레이션 면에 사영된다. CCD 카메라는 대상물과 사영된 빔이 교차한 평면을 측정한다. 그리고 3차원 데이터는 측정된 값과 캘리브레이션 데이터를 이용하여 계산된다. 본 논문에서 제안한 방범은 3차원 정보를 간단한 삼각법으로 획득하였기 때문에 효율적인 측정시간과 메모리 절약의 이점을 가지고 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.372-374
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• 2009

In this research, an obstacle avoidance method is proposed. The common usage of a robot is indoor and the obstacles to the indoor robot is studied. The accurate detection of direction after overcoming the obstacles is necessary for performance of autonomous navigation and mission project. The sensors such as Laser, Ultrasound, PSD can be used to measure the obstacles. In this research, a PSD sensor is used to detect obstacles. It detects the height and width of obstacles located on the floor. Before measuring the obstacles, a calibration of the sensor was done and it produced a better accuracy. We have plotted an error graph using data obtained from the repeated experiments. The graph is fitted to a polynomial curve. The polynomial equation is used for the robot navigation. And in this research, a model of the error of the direction of the robot after overcoming obstacles was obtained also. The prototype of the obstacle and the error of the direction after overcoming the obstacles are modelled using a neural networks. The input of the neural network composed with the height of the obstacles, the speed of robot, the direction of wheels and the error of the direction. To implement the suggested algorithm, we set up a robot which is operated by a notebook computer. Experiment showed the suggested algorithm performed well.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.203-207
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• 2003

Due to the inherent nature of the low flying UAV, obstacle detection is a fundamental requirement in the flight path to avoid the collision from obstacles as well as manned aircraft. In this paper, a preliminary sensor requirements of an obstacle detection system for UAV in low-altitude flight are analyzed, and the automated obstacle detection sensor system is proposed assessing both passive and active sensors such as EO camera, IR, Laser radar, microwave and millimeter radar. In addition, TCAS (Traffic Alert and Collision Avoidance System) are reviewed for the collision avoidance of the manned aircraft system. It is suggested that small-sized radar sensor is the best candidate for the smart UAV because an active radar can provide the real-time informations on range and range rate in the all-weather environment. However, an important constraints on small UAV should be resolved in terms of accommodation of the mass, volume, and power allocated in the payload of the UAV system design requirements.