• Composites Research
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• v.25 no.6
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• pp.236-240
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• 2012

The purpose of this study was to investigate the feasibility on the detection of dental composite delamination using a lock-in thermography method. Amplitude and phase images of detected thermal signals were analyzed according to the lock-in frequencies. At a lock-in frequency of 0.05 Hz, the ligament thickness of 0.5 mm in the specimen exhibited the highest amplitude contrast between defective area and sound area. For ligament thicknesses of 1 mm and 1.5 mm, delamination detection was possible at 0.025 Hz and 0.01 Hz through the amplitude differences. At lock-in frequencies of 0.006 Hz and 0.01 Hz, ligament thickness 0.5 mm exhibited the highest phase contrast. For ligament thicknesses of 1 mm and 1.5 mm, the phase contrast exhibited possible detection of delamination at 0.006-0.1 Hz.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.289-292
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• 2010

본 연구에서는 ISM 밴드 소출력 무선 통신을 이용한 수액세트 감시시스템 개발에 대하여 연구하였다. 사회가 발전하면서 복지 수요가 증가되고 있으며 특히 의료 서비스에 대한 수요의 증가가 예상되고 있다. 유비쿼터스를 이용한 각종 의료장비들이 개발되고 있다. 본 논문에서는 병원의 응급실이나 중환자실과 같이 수액공급시 수액의 주입여부, 종료여부를 감시하는 수액세트 자동 감시시스템을 개발하고자 한다. 수액세트 감시장치는 센서부와 수신부로 구성되며, 센서부는 수액 백으로부터 수액이 공급중인지 여부를 검출하고 검출된 신호를 처리한 후 447MHz ISM 밴드의 무선주파수를 이용하여 중앙통제실로 전송한다. 센서부는 동전형 리튬전지를 이용하여 3개월 사용하도록 설계 구현하였고 실내에서최대 65m까지 전송이 가능하였다. 수신부는 센서부에서 전송된 데이터를 표시하는 기능을 한다.

• Journal of Sensor Science and Technology
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• v.7 no.3
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• pp.197-202
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• 1998

The human pulse wave is a vital biosignal that includes the diagnostic data related with the heart and the cardiovascular system of human body. Based on the mechanical transducing method, a pulse detection transducer using optical fiber was developed to acquire the pulses non-invasively. To improve the detection efficiency, we proposed a new design that consists of two combinational parts; detecting part, which is in contact with the pulsating skin and transmits the displacement motion of the pulsating skin to the sensing part, and sensing part, which converts the physical quantity transmitted from the detecting part to electronic signal. By using the new method, we confirmed that the proposed transducer can detect the C point(incisura) and the T wave(tidal wave) which is not easily detected by existing transducers.

• Smart Media Journal
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• v.4 no.4
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• pp.9-17
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• 2015

Recently the need for advanced security technologies are increasing as the occurrence of intelligent crime is growing fastly. Previous liveness detection and fake face detection methods are required for the improvement of accuracy in order to be put to practical use. In this paper, we propose a new liveness detection method using pupil reflection, and new fake image detection using Adaboost detector. The proposed system detects eyes based on multi-scale Gabor feature vector in the first stage, The template matching plays a role in determining the allowed eye area. And then, the reflected image in the pupil is used to decide whether or not the captured image is live or not. Experimental results indicate that the proposed method is superior to the previous methods in the detection accuracy of fake images.

• Proceedings of the Acoustical Society of Korea Conference
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• 1993.06a
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• pp.229-232
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• 1993

이 논문은 최근에 개발된 실시간 음성부 검출 알고리즘[1]을 TMS320C30 System board와 IBM PC486을 이용한 implementation에 관한 논문이다. 음성부 검출 알고리즘은 Energy와 LCR(Level Crossing Rate)를 이용하여 각 frame을 음성/묵음으로 분류하는 방법을 사용하였고 DSP 보드를 사용하여 한 frame이 입력되면 다음 frame이 입력되기 전에 그 frame에 대한 음성/묵음 분류를 하여 음성입력이 끝남과 동시에 음성이라고 판단되는 부분만을 DPS moemory상에 저장하므로 불필요한 memory의 낭비를 중이고 다음 단계의 음성처리를 위한 시간을 절약하였다. 이 알고리즘의 성능 평가를 위하여 Rabiner와 Sambur의 알고리즘과 한민수의 알고리즘과를 전문가가 수작업으로 찾아낸 결과와 비교 평가하였다. 알고리즘의 오차는 평균 남성 4.925ms, 여성 5.85ms로 1 frame 이내의 오차를 보였다.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.163-165
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• 2007

본 연구는 무전극 형광램프의 램프 이상 유무를 검출하여 램프에 이상이 발생한 경우 이를 검출하여 전자식 안정기 회로를 보호하는 방법을 제안하고 실험을 통해 검증한다. 제안된 보호회로는 램프 양단에 걸리는 전압을 검출하여 디지털 회로에서 이용할 수 있는 신호로 변환해주는 아날로그 회로부와 이 신호를 이용해 안정기 회로의 인버터 부에 공급되는 PWM 신호를 제거해 주는 디지털 회로부로 구성된다. 제안된 알고리즘은 개발 비교기 IC 소자와 EPLD를 이용해 간단한 회로로 제작되었으며, 차후 집적화에도 유리할 것으로 판단된다.

• Analytical Science and Technology
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• v.36 no.6
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• pp.300-314
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• 2023

The quality of the products was investigated by analyzing fluorine content, pH, preservatives and tar colors in 31 dentifrice products (6 items for children) and 15 mouthwash products (2 items for children) marketed. It was intended to provide correct information to consumers by checking whether the standards and product indications match. As a result of measuring the fluoride concentration, 26 dentifrice and 15 mouthwash products contained from 48 to 1,472 ppm and from 85 to 225 ppm, respectively. Fluorine detection rates of dentifrice and mouthwash products were 83.9 and 83.3 %, respectively showing similar levels. Of the 41 fluoride-detected dentifrice and mouthwash products, 40 were 90.7~109.8 % of the displayed amount and suitable for the fluorine content standard of 90.0 to 110.0 %, but one dentifrice was found to be inappropriate at 36.3 % of the content indicated on the product. The pH of the dentifrice was 5.1~9.4, and the mouthwash was 4.2~6.2, which met all standards. As a result of simultaneous analysis of the concentration of six preservatives, benzoic acid was detected the most in 15 cases with a 30.6 % detection rate, sorbic acid was detected in 9 cases (detection rate of 18.4 %), and all four types of methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate were not detected. As a result of analyzing the concentration of 10 types of tar colors, six types including red40, yellow4, yellow5, yellow203, green3, and blue1 were detected in a total of 9 cases (2 dentifrices and 7 mouthwashes) with blue1 being the most frequently detected. Detected fluorine concentration, added preservatives and tar colors were consistent with the product markings and it was well written on product packaging. The detected preservatives and tar colors were at a safe level due to low risk compared to Acceptable Daily Intake.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.316-323
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• 2021

A total of 106 samples (nuts, nut products, oilseeds, oilseed products, seed for beverage products) were simultaneously analyzed with LC/MS/MS method. The tested mycotoxins were aflatoxin (B₁, B₂, G₁, G₂), ochratoxin A, fumonisin (B₁, B₂), and zearalenone. Mycotoxins were detected in 37 of 106 samples (35%), and two or more mycotoxins were simultaneously detected in 9 of 106 samples (8.5%). Aflatoxin, ochratoxin A, fumonisin and zearalenone were detected at the range of 0.08-1.45 ㎍/kg, 17.29 ㎍/kg, 1.16-14.89 ㎍/kg and 0.12-12.69 ㎍/kg, respectively. The results revealed that the most frequently detected mycotoxin was zearalenone (23%), followed by aflatoxin (13%), fumonisin (8%) and ochratoxin A (1%). Detection rates of nuts and oilseeds were 35% and 33%, respectively, and detection rates of their processed foods were 44% and 46%, respectively. The detection rate of mycotoxins was 10% higher in processed foods than in nuts and oilseeds. Mycotoxins are physicochemically stable and can persist during food processing and cooking, making management of mycotoxins in raw materials a concern of high importance.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1793-1795
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• 2004

지금까지 변전소나 개폐소에서 전류, 전압을 계측하는 수단으로서 주로 철심과 권선으로 구성되어진 변류기(CT), 계기용 변압기(PT, PD)가 사용되어 왔다 최근, 2차측의 계측기나 보호 Relay의 Digital화가 진전되어, 또한 이것을 Digital Network으로 종합한 Intelligent 변전소의 구축이 검토되어짐에 따라 Digital Network에 대응한 신형 CT, VD가 요구되어 지고 있다. 상기와 같은 요구로 인해 당사에서는 CT는 검출부에 Rogowski Coil을 적용하며 그 후단에 적분기를 설치하였으면, VD는 검출부에 중간 전극을 이용해서 분압하는 방식인 Capacitive Voltage Divider를 사용하고 증폭기를 삽입하여, 각각 요구되는 전압 신호를 얻었다. 이러한 신형 CT/VD의 적용으로 종래의 CT/PT가 차지하는 공간이 필요 없게 되어 컴팩트한 GIS의 구조가 능하게 되어 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.336-342
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• 2003

In this paper, a new differential detector is introduced, in which a solar cell is used to reduce the low frequency interference from environmental optical noise. The solar cell also supplies electrical power to the detector circuit using the optical noise power. The DC voltage from the solar cell is used as a power supply to the detector, and the AC voltage is used to reduce the optical noise in a photodiode with the differential detection method. The signal to noise ratio was improved by about 20 dB.