• Composites Research
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• 제20권6호
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• pp.21-27
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• 2007

복합재 보강판에 영구히 부착된 배열 압전 능동 센서를 사용하여 저속 충격 손상을 탐지하였다. 압전 능동센서를 사용하여 구조에 램파를 전파시키기 위한 다양한 진단신호를 생성하였으며, 손상으로 인한 구조 진동의 특성 변화를 탐지하기 위하여 그 응답을 측정하였다. 이 신호 변화 특징을 한 개의 손상 지수로 표현하기 위하여 3가지 알고리즘-ADI(Active Damage Interrogation), TD RMS (Time Domain Root Mean Square), STFT(Short Time Fourier Transform) -이 검토되었다. 손상 탐지시험을 수행하여, 사용한 기법과 진단신호로 저속 충격으로 인한 두 개의 층간분리를 탐지하였으며, 그 위치를 추정하였다.

• 대한전자공학회논문지TC
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• 제45권5호
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• pp.1-11
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• 2008

무선 센서 네트워크(Wireless Sensor Network : WSN)는 U-City 같은 우리 삶의 편의성 향상을 위한 서비스에 활용은 물론이거니와 환경오염, 터널 및 건축물의 붕괴, 태풍, 지진 등의 재난 감시, 위험물 진단 시스템 등에 다양하게 적용되고 있다. 본 논문에서는 이러한 WSN을 다양한 형태의 휴대 단말 및 네트워크 카메라와 연동하여 보다 효율적이고 가치 있는 정보 서비스 제공을 위한 MUSNEMO(Multi-sensor centric Ubiquitous Smart sensor NEtwork using MObile devices) 시스템을 제안하였다. 제안된 시스템은 IEEE 802.15.4 표준을 기반으로 스마트 센서 네트워크를 구성하며, 또한 제안한 시스템 구조의 활용성 검증을 위하여 다섯가지 응용 센서(자기, 조도, 소리, 모션, 진동)를 가진 망을 구성하여 센싱 이벤트 요청 및 제공 테스트를 수행하였다.

• 대한의용생체공학회:의공학회지
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• 제26권5호
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• pp.271-282
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• 2005

There are strong demands for accurate, fast, and inexpensive devices in the medical diagnostic laboratories, such as biosensors and chemical sensors. Biosensors can provide the reliable and accurate informations on the desired biochemical parameters, which is an essential prerequisite for a patient before going for a treatment. They can be used for continuous measurements of metabolites, blood cations, gases, etc. Of these, electrochemical biosensors play an important role in the improvement of public health, because rapid detection, high sensitivity, small size, and specificity are achievable for clinical diagnostics. In this paper, the clinical applications with electrochemical biosensors are reviewed. An attempt is also made to highlight some of the trends that govern the research and developments of the important biosensors that are associated to clinical diagnosis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1616-1618
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• 2001

In recent the on-line partial discharge (PD) measurement using sensors, such as EMC, SSC, RTD and RFCT, as an indicator of stator winding insulation condition has been developed. RFCT sensor was placed arounding a grounding lead of surge capacitor to detecting PD. Trend of PD magnitude/phase angle/pulse number over time are useful parameter to diagnosis aging state. We have developed Radio Frequency Current Transformer(RFCT) sensor which is suitable for PD diagnostic measurement in 6.6kV rotating machines. In this paper, we describe the characteristics of RFCT sensor, such as frequency and PD magnitude using 6.6 kV model stator winding in Lab.

• 한국전기전자재료학회논문지
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• 제28권8호
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• pp.539-543
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• 2015

At present, the development of a detection device in order to prevent accidents due to wire deterioration in the distribution lines is required. Distribution line is not possible to check the internal state in a normal way because it is covered with the coating. Accordingly, various eddy current techniques that is the non-destructive test (NDT) techniques have been applied to solve this problem. In this paper, we have seen examining the characteristic change of the eddy current sensor according to the simplified shape of the sensor in order to solve the problems for the simplified shape that is generated when the simulation for the shape of the eddy current sensor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.130-130
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• 2000

This paper presents a robust fault diagnosis and fault tolerant control lot the actuator and sensor faults in the closed-loop systems affected by unknown inputs or disturbances. The fault diagnostic scheme is based on the residual set generation by using robust Parity space approach. Residual set is evaluated through the threshold test and then fault is isolated according to the decision logic table. Once the fault diagnosis module indicates which actuator or sensor is faulty, the fault magnitude is estimated by using the disturbance-decoupled optimal state estimation and a new additive control law is added to the nominal one to override the fault effect on the system. Simulation results show that the method has definite fault diagnosis and fault tolerant control ability against actuator and sensor faults.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1659-1661
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• 2003

Recently, diagnostic techniques have been investigated to defect a partial discharge in high voltage electrical equipment. We have studied the characteristics of the acoustic partial discharge originating from the electrical defects in cubicle GIS(C-GIS). An acoustic emission(AE) sensor is used on the enclosure to detect partial discharge source because the sensor is sensitive to stress waves in its frequency range that may not be from a partial discharge source. AE signal is analyzed with phase-magnitude-frequency number(${\Phi}$-V-n) and pulse per second(PPS). Experience result has shown that the omitted acoustic signal has phase dependency and phase shift characteristic according to increase with applied voltage. These result will be helpful to the pattern recognition of the acoustic partial discharge in a C-GIS.

• 센서학회지
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• 제22권4호
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• pp.281-285
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• 2013

In this study a biosensor was developed by using Drosophila cells expressing a gustatory receptor Gr5a and an ion sensitive field effect transistors (ISFETs) sensor device, which demonstrated significant compatibility with the Drosophila cells expressing Gr5a and their response to sugar. These results suggested that the newly developed cell based biosensor has a potential as a simple and easy screening device for Alzheimer's disease in the future.

• 한국정밀공학회지
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• 제14권11호
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• pp.147-153
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• 1997

Fault diagnosis technique in machining system which is one of engineering techniques absolutely necessary to automation of manufacturing system has been proposed. As a whole, diagnosis process is explained by two steps: sensor data acquisition and reasoning current state of system with the given sensor data. Flexible disk grinding process implemented in milling machine was employed in order to obtain empirical manufacturing process information. Resistance force data during machining were acquired using tool dynamometer known as sensor which is comparably accurate and reliable in operation. Tool status during the process was analyzed using influnece diagram assigning probability from the statistical analysis procedure.

• Imaging Science in Dentistry
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• 제47권4호
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• pp.233-239
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• 2017

Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor(CMOS) intraoral sensor. Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis. Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and inter-observer agreement was achieved. Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients