• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.602-605
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• 2000

Recently, a study of intellectual smell recognition system is applied for the various fields such as control of food processing and survey of decay. A basic gas recognition system was implemented gases using four metal oxides semiconductor sensors as inputs. A CPLD chip of twenty thousand gates level was used for this purpose. The CPLD chip was designed and the availability of the one chip smell recognition system was tested.

• Journal of the Korean Society of Visualization
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• v.7 no.2
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• pp.17-21
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• 2010

This paper presents the fabrication and performance measurement of a temperature sensor array on a flexible substrate attachable to a curved surface using MEMS technology. Specifically, the fabrication uses the well-developed printed circuit board fabrication technology for complex electrode definition. The temperature sensor array are lifted off with a $10{\times}10$ matrix in a $50\;mm{\times}50\;mm$ to visualize temperature distribution. Copper is used as temperature sensing material to measure the change in resistances with temperature increase. In a thermal oven with temperature control, the temperature sensor array is Characterized. The constant slope of resistance change is obtained and temperature distribution is measured from the relationship between resistance and temperature.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.269-274
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• 2011

The purpose of hull stress monitoring system(HSMS) is to lead hull structure to be safer at lower cost. We proposed a hull stress monitoring system for leisure boats using fiber-optic bragg grating(FBG) strain sensor. Fiber optic sensors are well suited for structure monitoring system, due to their ability to withstand harsh environments, immunity to electromagnetic interference, and reduce cabling installation cost when employing wavelength multiplexing. This paper presents an overview of current research and design of hull stress monitoring system for leisure boats.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.274-274
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• 2010

최근 들어 나노선을 이용한 pn 접합 소자 연구 결과가 매우 활발하게 보고되고 있다. 그러나, 서로 다른 두 종류의 나노선으로 pn 접합 어레이 구조의 소자를 제작할 때, 나노선을 원하는 위치에 정렬하는 기술상의 어려움이 큰 걸림돌이 된다. 본 연구에서는 p-CNT와 n-$SnO_2$ 나노선을 이용한 pn 접합 어레이 구조를 제작할 수 있는 독창적인 공정기술을 제안한다. 먼저 $SiO_2$가 300 nm 성장된 Si 기판을 선택적으로 패터닝하여 BOE (6:1) 용액으로 $SiO_2$ 층을 80 nm 정도 선택적으로 에칭한 후, 선택적으로 에칭된 표면에 슬라이딩 장비를 이용하여 화학기상증착법(chemical vapor deposition: CVD)으로 성장된 n-$SnO_2$ 나노선을 전이시킨다. 그 다음 thermal tape를 이용하여 CVD 법으로 성장된 랜덤 네트워크 형태의 CNT를 $SnO_2$ 나노선이 전이된 기판 위에 전이 시킨다. 이때 성장된 CNT 필름 중 금속성 나노선을 통한 전하 이동을 감소시키기 위해, 촉매로 사용되는 페리틴의 농도를 낮춰서 전체적인 CNT의 농도를 줄이는 방법을 이용하였다. 따라서, 성장된 CNT 필름은 별도의 후처리 없이 p-형의 반도체성을 보였다. 제작된 pn-소자는 정류비가 ~103 인 정류특성을 보였으며, 254 nm 파장의 UV lamp를 조사하여 광전류가 발생하는 것을 확인하였다. 연구결과는 이종의 나노선 접합에 의한 다이오드 응용과 UV 센서응용 가능성을 보여준다.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.253-259
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• 2004

in this study, we developed a Monte Carlo imaging simulation code written by the visual C$\^$++/ programing language for design optimization of a digital X-ray imaging system. As a digital X-ray imaging system, we considered a Gd$_2$O$_2$S(Tb) scintillator and a photosensor array, and included a 2D parallel grid to simulate general test renditions. The interactions between X-ray beams and the system structure, the behavior of lights generated in the scintillator, and their collection in the photosensor array were simulated by using the Monte Carlo method. The scintillator thickness and the photosensor array pitch were assumed to 66$\mu\textrm{m}$ and 48$\mu\textrm{m}$, respertively, and the pixel format was set to 256 x 256. Using the code, we obtained X-ray images under various simulation conditions, and evaluated their image qualities through the calculations of SNR (signal-to-noise ratio), MTF (modulation transfer function), NPS (noise power spectrum), DQE (detective quantum efficiency). The image simulation code developed in this study can be applied effectively for a variety of digital X-ray imaging systems for their design optimization on various design parameters.

• Journal of Sensor Science and Technology
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• v.22 no.3
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• pp.219-222
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• 2013

The exhaled breath contains gases generated from human body. When disease occurs in the body, exhaled breath may include gas components released from disease metabolism. If we can find specific elements through analysis of the exhaled gases, this approach is an effective way to diagnose the disease. The lung function has a close relationship with exhalation. Exhaled gases from COPD (Chronic Obstructive Pulmonary Disease) patients can be analyzed by gas chromatography-mass spectroscopy (GC-MS) and a gas sensor system. The exhaled breath for healthy person and COPD patients had different components. Significantly more benzendicarboxylic acid was detected from COPD patients than in healthy persons. In addition, patients had a variety of decane. Phosphorous compounds with different isomers were detected from patients. The results obtained by gas sensor system were processed by PCA (Principal Component Analysis). The PCA results revealed distinct difference between the patients and healthy people.

• Journal of Sensor Science and Technology
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• v.27 no.2
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• pp.118-125
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• 2018

An evaluation system for an electronic-nose concept using three types of metal oxide gas sensors that react similarly to the human olfactory cells was constructed for the quantitative and qualitative evaluation of aroma fragrances. Four types of aroma fragrances (lavender, orange, jasmine, and Roman chamomile), which are commonly used in aromatherapy, were evaluated. All the gas sensors reacted remarkably to the aroma fragrances and the good correlation of r=0.58-0.88 with the aromatic odor intensities by olfaction was confirmed. From the results of the analysis of an electronic-nose concept for classifying the characteristics of aroma oil fragrances, aroma oils could be classified using the fragrance characteristics and oil extraction methods with the cumulative variability contribution rate of 95.65% (F1: 69.65%, F2: 26.03%) by principal component analysis. In the pattern recognition based on the artificial neural network, the four aroma fragrances were 100% recognized through the training data of 56 cases (70%) out of 80 cases, and the pattern recognition rate was 57.1%-71.4% through the validation and testing data of 24 cases (30%). The pattern recognition success rate through all confusion matrices was 82.1%, indicating that the classification of aroma oil fragrances using the three types of gas sensors was successful.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.21-30
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• 2006

The IEEE 1451.4 standards defines an architectural model for interfacing smart transducers for sensors & actuators. This standard allows analogue transducers to communicate their identification and calibration data in a digital format. A digital format is called TEDS(transducer electronic data sheet). However, the standard template of IEEE 1451.4 TEDS do not supports gas sensors to use in electronic nose system such as may sensors. In this paper, a solution to standardize sensors for electronic nose systems is presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12C
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• pp.1216-1223
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• 2006

In many imaging devices, a single image sensor is used, which is covered by a color filter array to filter out the specific color components from light. Since an image acquired from this image sensors have a color components at each pixel, it is needed to be reconstructed to a perfect image. In this paper, a new color interpolation method for the imaging devices having a single image sensor is proposed. The proposed method improves a edge sensing function to obtain satisfactory results in edges of an image, md presents a new inter-channel correlation for improving interpolation performance in smooth region. We have compared our method with several exiting methods, and our experimental results have proved better interpolation performance in comparing with the other results.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.258-263
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• 2015

In order to prevent drink-driving by detecting concentration of alcohol from driver's exhale breath, twenty chemical sensors fabricated. The one of purposes for sensor array which consists of those sensors is to discriminate between target gas(alcohol) and interference gases($CH_3CH_2OH$, CO, NOx, Toluene, and Xylene). Wilks's lambda was presented to achieve above purpose and optimal sensors were selected using the method. In this paper, step-wise sensor elimination based on Euclidean distance was investigated for selecting optimal sensors and compared with a result of Wilks's lambda method. The selectivity and sensitivity of sensor array were used for comparing performance of sensor array as a result of two methods. The data acquired from selected sensor were analyzed by pattern analysis methods, principal component analysis and Sammon's mapping to analyze cluster tendency in the low space (2D). The sensor array by stepwise sensor elimination method had a better sensitivity and selectivity compared to a result of Wilks's lambda method.