• 정보통신설비학회논문지
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• 제9권4호
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• pp.147-152
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• 2010

Gas sensor array can be widely applied to atmosphere environment, quality control of food, and medical fields etc. So for the commercialization and popularization of sensor technology, this paper looked into the method to provide users with general purpose smart phone and gas sensor array linked together. The reviewed system can detect unknown gas in the air and inform users using smart phone by arraying 8 kinds of common use gas sensor. This system is composed of the sensor module, communication module between sensor array and smart phone application software. In this paper, this prototype system demonstrate convincingly that the application of Gas sensor array to smart phone is a good outlook.

• 센서학회지
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• 제24권1호
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• pp.29-34
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• 2015

This study aimed to evaluate the characterization of a metal oxide semiconductor and electrochemical gas sensor array for measuring wastewater odor. The sensitivity of all gas sensors observed in sampling method by stripping was 6.7 to 20.6 times higher than that by no stripping, except sensor D (electrochemical gas sensor). The average reduction ratio of sensor signal as a function of initial dilution rate of wastewater was in the order of food plant > food waste reutilization facility > plating plant. The sensitivity of gas sensors was dependent on both the type of wastewater and the dilution rate. The sensor signals observed by the gas sensor array were correlated with the dilution factor (OU) calculated by the air dilution sensory test with several wastewater ($r^2=0.920{\sim}0.997$), except the sensor signals of sensor D measured in the plating plant wastewater. It seems likely that the gas sensor array plays a role in the evaluation of odor in wastewater and is useful tool for on-site odor monitoring in the wastewater facilities.

• Journal of information and communication convergence engineering
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• 제2권1호
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• pp.22-25
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• 2004

A highly sensitive ammonia gas sensor using thick-film technology has been fabricated and examined. The sensing material of the gas sensor is FeOx-$WO_{3}-SnO_{2}$ oxide semiconductor. The sensor exhibits resistance increase upon exposure to low concentration of ammonia gas. The resistance of the sensor is decreased, on the other hand, for exposure to reducing gases such as ethyl alcohol, methane, propane and carbon monoxide. A novel method for detecting ammonia gas quite selectively utilizing a sensor array consisting of an ammonia gas sensor and a compensation element has been proposed and developed. The compensation element is a Pt-doped $WO_{3}-SnO_{2}$gas sensor which shows opposite direction of resistance change in comparison with the ammonia gas sensor upon exposure to ammonia gas. Excellent selectivity has been achieved using the sensor array having two sensing elements.

• 센서학회지
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• 제20권6호
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• pp.428-433
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• 2011

We report on the building of a micro sensor array based on typical semiconductor fabrication processes aimed at monitoring selectively a specific gas in ambient of other gases. Chemical sensors can be applied for an electronic nose and/or robots using this technique. Microsensor array was fabricated on the same chip using 0.6${\mu}m$ CMOS technology, and unique gas sensing patterns were obtained by principal component analysis from the array. $SnO_2$/Pt sensor for CO gas showed a high selectivity to buthane gas and humidity. $SnO_2$ sensor for hydrogen gas, however, showed a low selectivity to CO and buthane gas. We can obtain more distinguishable patterns that provide the small sensing deviation(the high seletivity) toward a given analyte in the response space than in the chemical space through the specific parameterization of raw data for chemical image formation.

• 대한전자공학회논문지SD
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• 제40권12호
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• pp.17-23
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• 2003

서로 다른 동작온도를 가지는 12개의 감지막으로 구성된 고집적형 센서어레이(다이아프램의 크기가 3×5㎟가 설계되고 열동작의 관점에서 최적화되었다. 이 센서어레이는 에칭된 실리콘기판과 접합된 얇은 유리기판 위의 중앙에 하나의 히터가 위치하고 양쪽에 동작온도가 다른 감지박막이 위치하도록 설계됨으로써 개별 마이크로센서 보다 동시에 훨씬 많은 정보를 얻을 수 있는 장점을 가지고 있다. 제안된 마이크로센서 어레이는 다이아프램의 중앙에 하나의 히터만을 가지는 구조를 하고 있기 때문에 고집적 어레이구조를 실현하면서도, 히터를 중심으로 감지박막의 동작온도에 따라 다양한 감지특정을 얻을 수 있다. 또 히터 양쪽의 감지박막의 종류를 다르게 함으로써 다이아프램위의 전 감지막이 모두 다른 감지특성을 가지게 되어 고집적 센서어레이를 구현하기 용이한 구조로 밝혀졌다.

• 센서학회지
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• 제17권6호
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• pp.406-413
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• 2008

We have been implemented simple statistical pattern recognition methods for harmful gases classification using gas sensors array fabricated by MEMS (Micro Electro Mechanical System) technology. The performance of pattern recognition method as a gas classifier is highly dependent on the choice of pre-processing techniques for sensor and sensors array signals and optimal classification algorithms among the various classification techniques. We carried out pre-processing for each sensor's signal as well as sensors array signals to extract features for each gas. We adapted simple statistical pattern recognition algorithms, which were PCA (Principal Component Analysis) for visualization of patterns clustering and MLR (Multi-Linear Regression) for real-time system implementation, to classify harmful gases. Experimental results of adapted pattern recognition methods with pre-processing techniques have been shown good clustering performance and expected easy implementation for real-time sensing system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.21-24
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• 2002

A sensor array (35mm'! in diaphragm dimension) of 12 sensing elements with different operating temperatures was optimized with respect to thermal operation. This sensor array with single heater on a glass diaphragm over back-etched silicon bulk realizes a novel concept of a sensor array: an way of sensor elements operated at different temperatures can yield more information than single measurement. The proposed micro sensor array could provide well-integrated way structure because it has only single heater at the center of the diaphragm and used the various sensing properties of two kinds of metal oxide layers with various operating temperatures.

• Journal of information and communication convergence engineering
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• 제4권1호
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• pp.18-22
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• 2006

A small-sized gas identification system has been fabricated and characterized using an integrated gas sensor array and artificial neural-network. The sensor array consists of four thick-film oxide semiconductor gas sensors whose sensing layers are $In_{2}O_{3}-Sb_{2}O_{5}-Pd-doped\;SnO_2$ + Pd-coated layer, $La_{2}O_{5}-PdCl_{2}-doped\;SnO_2,\;WO_{3}-doped\;SnO_{2}$ + Pt-coated layer and $ThO_{2}-V_{2}O_{5}-PdCl_{2}\;doped\;SnO_{2}$. The small-sized gas identification instrument is composed of a GMS 81504 containing an internal ROM (4k bytes), a RAM (128 bytes) and four-channel AD converter as MPU, LEDs for displaying alarm conditions for three gases (liquefied petroleum gas: LPG, liquefied natural gas: LNG and carbon monoxide: CO) and interface circuits for them. The instrument has been used to identify alarm conditions for three gases among the real circumstances and the identification has been successfully demonstrated.

• 대한전자공학회논문지SD
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• 제37권11호
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• pp.9-17
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• 2000

폭발성 가스의 종류 및 그 양을 검지하기 위한 10개의 개별 센서가 한 기판위에 집적된 센서어레이를 개발했다. 이 센서어레이는 각종 가스에 대해 다양한 감도 패턴을 가지며, $SnO_2$를 모물질로 하는 10개의 산화물 반도체 가스센서로 구성하였다. 나노사이즈이며 큰 비표면적을 가진 모물질에 서로 다른 첨가물을 첨가하여 감지물질를 제작함으로써 저농도에 대한 감도 및 재현성을 높였고, 센서어레이 전반에서 균일한 온도 분포가 되도록 설계하였다. $400^{\circ}C$에서 동작하는 센서어레이로부터 얻은 감도를 이용하여 주성분 분석 기법을 통해 폭발 하한값의 범위에서 부탄, 프로판 그리고 메탄 등과 같은 폭발성 가스의 종류 및 양을 신뢰성 있게 식별할 수 있었다.

• 센서학회지
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• 제22권4호
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• pp.286-291
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• 2013

This paper presents to analyze patterns from single and complex malodors using gas sensor array based on metal oxide semiconductors. The aim of research is to identify and discriminate single malodors such as $NH_3$, $CH_3SH$ and $H_2S$ and their mixtures according to concentration levels. Measurement system for analyzing patterns from malodors is constructed by an array of metal oxide semiconductor sensors which are available commercially together with associate electronics. The patterns from sensory system are analyzed by Principal Component Analysis (PCA) which is simple statistical pattern recognition technique. Throughout the experimental trails, we confirmed the experimental procedure for measurement system such as sensors calibration time and gas flow rate, and discriminated malodors using pattern analysis technique.