• 한국정밀공학회지
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• 제22권9호
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• pp.85-92
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• 2005

This paper describes the recognition method of small-obstacles using a camera for a mobile robot in indoor environment. The technique of image processing using a camera has been widely used for an automaton of industrial system, an inspection of inferior goods, a lookout of an invader, and a vision sensor of intelligent robot. Mobile robot could meet small-obstacles such as a small plastic bottle of about 0.5 l in quantity, a small box of $7{\times}7{\times}7cm^3$ in volume, and so on in its designated path, and could be disturbed by them in the locomotion of a mobile robot. So, it is necessary to research on the recognition of small-obstacles using a camera and program. In this paper, 2-D image processing algorism and method fur recognition of small-obstacles using a camera for a mobile robot in indoor environment was developed. The characteristic test of the developed program to confirm the recognition of small-obstacles was performed. It is shown that the developed program could judge the size and the position of small-obstacles accurately.

• 자동차안전학회지
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• 제10권4호
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• pp.33-39
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• 2018

Recently, the automobile industry has developed ADAS (Advanced Driver Assistance System) to prevent traffic accidents and reduce driver's driving burden. Among the ADAS, the LKAS (Lane Keeping Assistance System) is a support system for the convenience and safety of the driver, and the main function is to maintain the driving lane of the vehicle. LKAS is a system that uses radar sensor and camera sensor to collect information about the position of the vehicle in the lane and to support keeping the lane through control if necessary. In many countries, LKAS has already been commercialized and the convenience and safety of drivers have been improved. The international LKAS evaluation test procedure is being developed and discussed by standardization committees such as the ISO (International Organization for Standardization) and the Euro NCAP (New Car Assessment Program). In Korean, the LKAS test method is specified in the KNCAP (Korean New Car Assessment Program), but the evaluation method is not defined. Therefore, the LKAS test procedure that meets international standards and is suitable for domestic road environment is necessary. In this paper, development of LKAS test evaluation scenarios that meets international standards and considering domestic road environment, and the formula that can evaluate the result value after control as the relative distance of lane and the front wheel are suggested. And a comparative analysis was conducted to verify the validity of the suggested scenario and formula. The test evaluation was conducted using the vehicle equipped with the LKAS.

• Smart Structures and Systems
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• 제16권4호
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• pp.683-699
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• 2015

Time Domain Reflectometry (TDR) has been extensively applied for various laboratory and field studies. Numerous different TDR probes are currently available for measuring soil moisture content and detecting interfaces (i.e., due to landslides or structural failure). This paper describes the development of an innovative spiral-shaped TDR probe that features much higher sensitivity and resolution in detecting interfaces than existing ones. Finite element method (FEM) simulations were conducted to assist the optimization of sensor design. The influence of factors such as wire interval spacing and wire diameter on the sensitivity of the spiral TDR probe were analyzed. A spiral TDR probe was fabricated based on the results of computer-assisted design. A laboratory experimental program was implemented to evaluate its performance. The results show that the spiral TDR sensor featured excellent performance in accurately detecting thin water level variations with high resolution, to the thickness as small as 0.06 cm. Compared with conventional straight TDR probe, the spiral TDR probe has 8 times the resolution in detecting the water level changes. It also achieved 3 times the sensitivity of straight TDR probe.

• 센서학회지
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• 제19권1호
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• pp.17-24
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• 2010

This paper describes a real time reliable monitoring method and analysis system using wrist type oximeter for ubiquitous healthcare service based on IEEE 802.15.4 standard. Photoplethysmograph(PPG) is simple and cost effective technique to measure blood volume change. In order to obtain and monitor physiological body signals continuously, a small size and low power consumption wrist type oximeter is designed for the measurement of oxygen saturation of a patient unobtrusively. The measured data is transferred to a central PC or server computer by using wireless sensor nodes in wireless sensor network for storage and analysis purposes. LabVIEW server program is designed to monitor stress indicator from heart rate variability(HRV) and process the measured PPG to accelerated plethysmograph(APG) by appling second order derivatives in server PC. These experimental results demonstrate that APG can precisely describe the features of an individual's PPG and be used as estimation of vascular elasticity for blood circulation.

• Journal of Biosystems Engineering
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• 제35권2호
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• pp.132-137
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• 2010

Site-specific N application for corn is one of the precision crop management. To implement the site-specific N application, various nitrogen stress sensing methods, including aerial image, tissue analysis, soil sampling analysis, and SPAD meter readings, have been used. Use of side-dressing, an efficient nitrogen application method than a uniform application in either late fall or early spring, relies mainly on the capability of nitrogen deficiency detection. This paper presents map-based variable rate nitrogen application based using a multi-spectral corn nitrogen deficiency(CND) sensor. This sensor assess the nitrogen stress by means of the estimated SPAD reading calculated from the corn leave reflectance. The estimated SPAD value from the CND sensor system and location information form DGPS of each field block was combined into the field map using a ArcView program. Then this map was converted into a raster file for a map-based variable rate application software. The relative SPAD (RSPAD = SPAD over reference SPAD) was investigated 2 weeks after the treatments. The results showed that the map-based variable rate application system was feasible.

• 센서학회지
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• 제10권5호
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• pp.329-336
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• 2001

This paper describes the steering control and geomagnetism cancellation for an autonomous vehicle using an MR sensor. The magneto-resistive (MR) sensor obtains the vector summation of the magnetic fields from embedded magnets and the Earth. The vehicle is controlled by the magnetic fields from embedded magnets. So, geomagnetism is the disturbance in the steering control system. In this paper, we propose a new method of the sensor arrangement in order to remove the geomagnetism and vehicle body interference. The proposed method uses two MR sensors located in a level plane and the steering controller has been developed. The controller has three input variables ($dB_x$, $dB_y$, $dB_z$) using the measured magnetic field difference, and an output variable (the steering angle). A simulation program was developed to acquire the data to teach the neural network, in order to test the ability of a neural network to learn the steering control process. Also, the computer simulation of the vehicle (including vehicle dynamics and steering) was used to verify the steering performance of the vehicle controller using the neural network. From the simulation and field test, good result was obtained and we confirmed the robustness of the neural network controller in a real autonomous vehicle.

• 센서학회지
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• 제22권2호
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• pp.136-143
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• 2013

In the study, novel blood pressure estimation method was proposed to improve the accuracy of oscillometric method. The proposed algorithm estimated the blood pressure by comparing and analyzing the point variation aspect of dicrotic notch on pulsating waveform during each cardiac cycle. The waveforms of each cardiac cycle were extracted by maximum points. The extracted pulsating waveforms were applied by re-sampling, end-matching, and normalization. The systolic and diastolic blood pressures were estimated by point variation aspect of dicrotic notch. The blood pressures, which were estimated from proposed algorithm, were compared and analyzed by blood pressures from oscillometric methods and auscultation. The systolic blood pressure from oscillometric methods were +0.88 mmHg more than proposed algorithm, and 1.875 less than the diastolic blood pressures from proposed algorithm. The systolic and diastolic blood pressures from auscultation were 2.89 mmHg and 3.44 mmHg less than the blood pressures from proposed algorithm. As the errors between blood pressures from proposed algorithm, oscillometric method and auscultation were less than 5 mmHg, the proposed algorithm was effective.

• 한국정보통신학회논문지
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• 제17권9호
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• pp.2167-2173
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• 2013

최근 실내 공기오염으로부터 발생되는 많은 문제점에 대한 관심이 증가하고 있으며, 실내 환경정보를 측정하여 사용자에게 사전 조치를 취할 수 있는 시스템에 대한 필요성이 점차 증대되고 있다. 이와 관련하여 본 논문에서는 휴대용 단말기, 환경 센서를 이용하여 각종 실내 환경정보를 측정할 수 있는 근거리 무선통신을 이용한 실내 환경정보 모니터링 시스템을 설계하고 구현하였다. 제안하는 시스템은 사용자의 휴대 단말기로 센서노드가 설치되어 있는 실내 환경 정보를 사전 인지하고, 위험 요소가 인지될 경우 적절한 대비를 취할 수 있는 장점이 있다.

• 한국산학기술학회논문지
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• 제21권6호
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• pp.640-645
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• 2020

전자기 유도 방식의 투명 전자 패턴을 이용한 입력장치의 안정적 생산을 위해서는 생산 공정에서 미리 패턴 검사가 필요한 실정이다. 손터치용 정전용량 패턴의 검사 방법은 다양하게 제시 되어왔으나, 투명 전자기 유도 방식의 패턴 검사방법은 관련 기술 자료를 찾기 힘든 실정이다. 본 연구에서는 메탈 메쉬형 패턴으로 제작된 융합형 전자기유도 센서의 검사방법을 개발하기 위하여, 측정 센서에서 노출된 FPCB 커넥터 부분만의 측정으로 센서 내부의 안테나 임피던스를 측정하기 위한 새로운 측정알고리즘과 측정 방법을 제안하였다. 제안된 검사방법은 자체 개발된 윈도우 운영프로그램으로 제어되는 컴퓨터의 명령에 따라 미리 설정된 특정 채널 간의 루프를 형성하는 마이크로프로세서로 구성된 제어 보드, 특정 채널 간의 임피던스를 고정밀도로 측정하는 LCR 메터 그리고 측정결과를 컴퓨터로 전송하는 통신 시스템으로 구성하였다. 제안된 시스템을 설계 제작하여 자동으로 설정된 채널 간의 측정을 수행하였으며, 9개의 시편에 대하여 임피던스를 실제 측정한 결과와 제안된 시스템으로 측정한 결과, 실제 제품에 사용되는 센서의 기능 불량을 검출할 수 있는 성능을 보임을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.407-410
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• 2002

Triangulation method, conoscopic holography method and interferometry method are analyzed for effective measurement of micro burr geometry, which is formed in micro drilling. To select proper sensor, cylinder with 0.5mm diameter is measured and the result shows that conoscopic holography method is effective for measuring highly inclined surface. Burr with 1.0mm height and 30$\mu\textrm{m}$ height are measured by all methods. The conoscopic holography method is probed to be most proper method for measuring micro burr. A Program for 3D display of measured burr is developed.