• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.208-217
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• 2016

This paper describes a simulation method to generate sensor measurements for location estimation of an underwater robot. Field trial of a navigation method of an underwater robot takes much time and expenses and it is difficult to change the environment of the field trial as desired to test the method in various situations. Therefore, test and verification of a navigation method through simulation is inevitable for underwater environment. This paper proposes a method to generate sensor measurements of range, depth, velocity, and attitude taking the uncertainties of measurements into account through simulation. The uncertainties are Gaussian noise, outlier, and correlation between the measurement noise. Also, the method implements uncertainty in sampling time of measurements. The method is tested and verified by comparing the uncertainty parameters calculated statistically from the generated measurements with the designed uncertainty parameters. The practical feasibility of the measurement data is shown by applying the measurement data for location estimation of an underwater robot.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.1
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• pp.36-45
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• 2010

This paper shows a multiplexing technique to maximize the application of a moire-fringe based fiber optic sensor to lots of structure. Especially, a novel fringe-based fiber optic sensor was proposed to overcome the difficulty of multiplexing of a previous moire-fringe-based fiber optic sensor. The novel fringe-based fiber optic sensor is composed of a single reflective fringe and two optical fibers. Therefore, the multiplexing is easily realized because of the simplicity of optic structure inside the sensor. This paper also proposed four models of the multiplexing techniques. The models are based on a wavelength division multiplexing(WDM) technique and a time division multiplexing(TDM) one. Basically, the models would be profitable for a general extrinsic fiber optic sensor such as the fringe-based fiber optic sensor. Finally, the real optic system was manufactured by using the proposed model and successfully examined to prove the feasibility of the model for the application.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.1131-1134
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• 2017

본 연구는 차동 용량형 섬유 압력 센서를 개발하고, 이를 깔창에 부착하여 보행 측정에 응용하는 것을 목적으로 한다. 차동 용량형 섬유 압력 센서는 3장의 전도성 섬유 사이에 2장의 절연체를 위치시키는 형태로, $5cm{\times}5cm{\times}0.23cm$ (가로 ${\times}$ 세로 ${\times}$ 두께) 크기로 제작하였다. 커패시턴스를 측정하기 위해 커패시턴스-디지털 변환칩(AD7152), ATMega328로 구성된 시스템을 제작하였고 PC로 데이터를 전송하여 모니터링을 수행하였다. 센서의 힘-커패시턴스 변화 특성 평가를 위해 센서에 가하는 중량을 65 kg 까지 5 kg 씩 증가시켜 가며 커패시턴스 변화를 측정하였다. 실험 결과, 무게에 따라 커패시턴스가 증가하는 것을 확인하였다. 보행 측정 가능성을 평가하기 위해 센서를 깔창에 부착한 후 보행 신호를 측정하였으며, 그 결과 보행에 따라 센서의 커패시턴스 값이 변화하는 것을 확인하였다. 이로부터 제작한 차동용량형 섬유 센서는 보행 측정에 활용할 수 있는 가능성을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.533-534
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• 2009

무선센서네트워크에서 많은 응용 프로그램들이 센서노드들의 위치 정보를 기반하기 때문에 센서노드에 대한 위치 측정은 매우 중요하다. 본 논문은 위치 정보를 알고 있는 소수의 앵커노드들을 사용하여 위치 측정 정확도를 높이고 주어진 위치 정보 메시지의 교환 비용을 줄이는 분산 위치 측정 기법인 Low-cost Localization using 2-hop Distance Anchors (LLTA)를 제안한다. LLTA는 높은 위치 측정 정확도를 위해 각각의 센서노드로부터 2 홉 거리 이내의 센서노드들의 위치 정보를 모으는 2-홉플러딩을 사용한다. 또한 2-홉 플러딩을 통해 얻은 위치 정보를 이용하여 센서노드가 위치할 수 있는 지역을 계산한 후 그리드 스캔 알고리즘을 사용하여 센서노드의 더 정확한 위치를 계산한다. 시뮬레이션 결과를 통해 LLTA가 기존의 위치 측정 기법들보다 위치 측정 정확도가 더 높고, 위치 정보 전달 비용이 더 낮음을 보인다.

• BT NEWS
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• v.11 no.2
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• pp.24-34
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• 2004

센서란 측정 대상물로부터 정보를 검지 또는 측정하여 그 측정량을 인식 가능한 유용한 신호로 변화하는 장치(device)로 정의할 수 있으며, 바이오센서(biosensor)는 생물학적 요소와분석 대상 물질과의 반응에서 나타나는 전기화학적 변화, 열에너지의 변화, 형광 또는 색의 변화 등을 인식 가능한 신호로 변환시켜 주는 장치와 결합하여 제작한 기구를 지칭한다. 바이오센서의 효시는 1962년 포도당을 측정하기 위해 Clark이 dialysis membrane을 이용하여 최초의 Glucose센서를 개발한 이래로 생물공학, 화학공학, 전자공학, 생명공학 및 컴퓨터 공학 등 여러 분야가 접목되면서 급속도로 연구 개발되어 왔다.(중략)

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.30-35
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• 2003

In this paper, the transverse strain was measured using polarization maintaining fiber Bragg grating(PMFBG) sensor. PMFBG sensor was fabricated using phase mask and Excidmer laser. The reflected wavelength of PMFBG sensor had dual peaks due to intrinsic birefringence. To find the polarization axes, peak sensitivity was measured under compression test. The signal characteristics of PMFBG sensor were also examined in embedding condition. The embedded PMFBG sensor in epoxy block was loaded for the transverse strain measurement, The wavelength-swept fiber laser(WSFL) was used to construct the PMFBG sensor system. Experiments showed that the PMFBG sensor could successfully measure the transverse strain.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.5
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• pp.436-441
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• 2009

A fiber optic sensor is prospective to be applied to structural health monitoring. Especially, a fiber Bragg grating(FBG) sensor is one of the most popular sensors for the structural health monitoring. The FBG sensor has several demodulation systems for tracking the shift of the Bragg wavelength. The dynamic bandwidth is dependent on the demodulation system. In this paper, the sensing mechanism is that the slope of the optical spectrum of FBG could be used as its sensitivity when the tunable laser shot the monochromatic laser wavelength at the highest slope point. In this technique, the high sensitivity is guaranteed even though the sensing range is limited. In an example of the application, the composite plate embedding a FBG sensor was manufactured by using an autoclave method and the above sensing mechanism was applied to the composite plate. Firstly, the natural frequencies of the plate were successfully measured by the FBG sensor during the impact hammer test. Secondly, a high-power speaker was used to force the plate to be vibrated at the specific frequency that was one of the natural frequencies. During the shaking, the FBG sensor measures the dynamic characteristics and ESPI was also used to measure the mode shape. From the two dynamic tests, the availability of the FBG sensor system and the ESPI was proven as a technique for measuring the dynamic characteristics of composite structure.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.110-116
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• 2009

This study was to verify and calibrate seven kinds of soil water sensors for volumetric soil water content(VSWC) measurement under field. Types of sensors were TDR (Time Domain Reflectometry) and FDR(Frequency Domain Reflectometry). Two kinds of TDR were TRIME(profile type), and Mini-TRASE(rod type). Five kinds of FDR were EasyAG, EnviroSCAN, PR-1(profile type), and WET-1(rod type). VSWC by TRIME and Mini-TRASE compared with VSWC by soil core showed the standard error of about 2.4%, and 1.4% which is the smallest value among all the sensors used in the experiment, respectively. The errors of EasyAG and EnviroSCAN analyzed with scaled frequency(SF) were about 2.6%, and 2.8% and those by 1 versus 1 correspondence were about 2.6%, and 2.6%, respectively. WET-1 showed about 2.0% of error, which is the smallest value among errors by FDR sensors. PR-1 with the error of about 4.7% should be hard for application in field. Therefore, users on soil water sensors have to take into consideration the errors of sensors revealed after the calibration for the correct measurement of VSWC in field. The rest except for PR-1 among the sensors could be used for VSWC measurement with 1.4~2.6% error.

• Journal of Sensor Science and Technology
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• v.7 no.2
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• pp.90-96
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• 1998

Non-contacting capacitive sensors, based on principle of the cross capacitor, for measuring small displacement less than $1.95{\pm}0.5\;mm$ have been fabricated and characterized. To overcome disadvantages of the existed capacitive sensors with 2-electrodes and 3-electrodes, the new sensor is consisted of 4-electrodes which are formed two electrode(high, low) and 2 guard electrodes on a sapphire plate with diameter 17 mm and thickness 0.7 mm, and are symmetrically situated with a constant gap of 0.2 mm between the electrodes. This sensor can be used for measuring both metallic and non-metallic target without ground connection, and is evaluated to the correlation coefficient of 0.9987 for the range of $1.95{\pm}0.5\;mm$ and that of 0.9995 for $1.95{\pm}0.25\;mm$ range.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.344-346
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• 2022

본 논문에서 거푸집의 가장취약 부분인 접합부위에 로드센서를 부착하여 실시간 콘크리트 측압을 측정 할 수 있으며, 관리자는 모니터링을 통하여 확인 할 수 있도록 하며 LORA의 저전력 장거리 통신망을 사용하는 디바이스를 개발하여 로드센서에 측정한 값을 데이터변경, 웹 기반의 클라우드 서비스로 발송하여 PC 및 Mobile로 확인 할 수 있는 시스템을 구축하였다. 여러가지 센서로부터 데이터를 수신하여 모바일로 송신해 주는 무선송수신기의 개발을 원하고 있으며, 하중센서, 경사도센서, 풍향센서 등 다중 데이터값을 수신할 수 있어야 한다. 이렇게 구성된 센서와 데이터의 수신을 통해서 콘크리트 타설시 발생하는 측압을 측정하고 공사기간 동안 별도의 전원 공급 없이 작동이 유지될 수 있는 시스템을 구축하였다. 수요자가 Application과 호환이 이루어져야 하며 또한 MEMS센서를 이용하여 상태를 모니터링 하고 임계값을 지정하여 이상 신호 발생시 위험상황에 대해서 인공지능기법을 이용하여 관리자에게 알림을 주어 효과적으로 사용할 수 있는 시스템을 개발하였다.