• 센서학회지
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• 제28권4호
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• pp.221-224
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• 2019

Based on the results of studies on acetone excretion in diabetic patients, a one - chip sensors array was fabricated by combining acetone-selective sensor materials and volatile-organic-compound sensitive sensor materials. An electonic-nose was implemented using a sensor array and confirmed selectivity for five gases. In this system, the excretion of diabetic patients and controls was sampled with solid phase microextraction fiber and transferred to the sensor array. Although the control and diabetic patients were distinct, several samples failed. In the control group, the results of blood tests were normal, but patients were highly obese. In addition, the gas chromatography mass spectrometry results for the subjects revealed chemicals that are external factors.

• 센서학회지
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• 제22권3호
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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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.251-252
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• 2006

A development of surface acoustic wave gas sensor to detecting volatile gas has been observed by monitoring output signal as function of time onto the network analyzer. The SAW sensor with a center frequency of 200MHz was fabricated on $42^{\circ}$ S-T Quartz substrates. Using the gas chromatography column has been selectivity. Experimental results, which show the phase change of output signal under the absorption of volatile gas onto sensors, were presented. The proposed sensor has the properties of high sensitivity compare to the conventional SAW gas sensor and chemical selectivity. Thus, it is thought these results are applicable for use in sensor array of an high performance electronic nose system.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2002년도 춘계학술대회 논문집
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• pp.356-360
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• 2002

산업의 발달과 더불어 CO, $H_2$S, S $O_2$등에 의한 대기오염이 심각해져 가스중독의 위험성이 고조되었을 뿐만 아니라, 생활수준의 향상으로 부탄(C$_4$ $H_{10}$)이나 프로판(C$_3$ $H_{8}$) 등의 폭발성 탄화수소계 가스들의 수요가 급증하는 가운데 가스폭발의 위험성이 대두되고 있다. 이에 대한 방비책으로 고감도 가스센서의 개발 뿐만 아니라 가스센서를 응용한 가스검출 및 가스식별 시스템의 개발이 시급한 실정이다. 본 연구에서는 반도체식 가스센서의 선택도에 대한 문제점을 개선하는 동시에 단일 센서신호의 드리프트에 대한 영향을 최소화하기 위해 반도체식 가스센서 어레이를 구성하고, 이로부터 검지된 가스별 입력 패턴데이터를 신경 회로망(neural network)에 적용함으로써 가스의 종류를 선택적으로 인식할 수 있는 가스인식 시스템을 개발하고자 한다.다.

• 한국재료학회지
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• 제33권5호
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• pp.195-204
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• 2023

Micro-electronic gas sensor devices were developed for the detection of carbon monoxide (CO), nitrogen oxides (NO_x), ammonia (NH₃), and formaldehyde (HCHO), as well as binary mixed-gas systems. Four gas sensing materials for different target gases, Pd-SnO₂ for CO, In₂O₃ for NO_x, Ru-WO₃ for NH₃, and SnO₂-ZnO for HCHO, were synthesized using a sol-gel method, and sensor devices were then fabricated using a micro sensor platform. The gas sensing behavior and sensor response to the gas mixture were examined for six mixed gas systems using the experimental data in MEMS gas sensor arrays in sole gases and their mixtures. The gas sensing behavior with the mixed gas system suggests that specific adsorption and selective activation of the adsorption sites might occur in gas mixtures, and allow selectivity for the adsorption of a particular gas. The careful pattern recognition of sensing data obtained by the sensor array made it possible to distinguish a gas species from a gas mixture and to measure its concentration.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.616-623
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• 2007

A dual micro gas sensor array was fabricated using nano sized $SnO_2$ thin films which had good sensitivities to CO and combustible gases, or $H_2S$ gas for air quality sensors in automobile. The already existed air quality sensor detects oxidizing gases and reducing gases, the air quality sensor(AQS), located near the fresh air inlet detected the harmful gases, the fresh air inlet door/ventilation flap was closed to reduce the amount of pollution entering the vehicle cabin through HVAC(heating, ventilating, and air conditioning) system. In this study, to make $SnO_2$ thin film AQS sensor, thin tin metal layer between 1000 and $2000{\AA}$ thick was oxidized between 600 and $800^{\circ}C$ by thermal oxidation. The gas sensing layers such as $SnO_2$, $SnO_2$(pt) and $SnO_2$(+CuO) were patterned by metal shadow mask for simple fabrication process on the silicon substrate. The micro gas sensors with $SnO_2$(+Pt) and $SnO_2$(CuO) showed good selectivity to CO gas among reducing gases and good sensitivity to $H_2S$ that is main component of bad odor, separately.

• 센서학회지
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• 제25권1호
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• pp.13-19
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• 2016

Nowadays, most major automobile manufacturers are very interested, and actively involved, in developing driver alcohol detection system for safety (DADSS) that serves to prevent driving under the influence. DADSS measures the blood alcohol concentration (BAC) from the driver's breath and limits the ignition of the engine of the vehicle if the BAC exceeds the reference value. In this study, to optimize the sensor array of the DADSS, we selected sensors by using three different methods, configured the sensor arrays, and then compared their performance. The Wilks' lambda, stepwise elimination and filter method (using a principal component) were used as the sensor selection methods [2,3]. We compared the performance of the arrays, by using the selectivity and sensitivity as criteria, and Sammon mapping for the analysis of the cluster type of each gas. The sensor array configured by using the stepwise elimination method exhibited the highest sensitivity and selectivity and yielded the best visual result after Sammon mapping.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.309-312
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• 2001

A primitive gas classification system which can classify limited species of gas was designed and simulated. The 'electronic nose' consists of an array of 4 metal oxide gas sensors with different selectivity patterns, signal collecting unit and a signal pattern recognition and decision Part in PLD(programmable logic device) chip. Sensor array consists of four commercial, tin oxide based, semiconductor type gas sensors. BP(back propagation) neutral networks with MLP(Multilayer Perceptron) structure was designed and implemented on CPLD of fifty thousand gate level chip by VHDL language for processing the input signals from 4 gas sensors and qualification of gases in air. The network contained four input units, one hidden layer with 4 neurons and output with 4 regular neurons. The 'electronic nose' system was successfully classified 4 kinds of industrial gases in computer simulation.

• 센서학회지
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• 제14권3호
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• pp.186-190
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• 2005

This paper describes the development of a surface acoustic wave gas sensor that is designed to detect volatile gas by monitering phase change of output signal as a function of time. The sensor consists of SAW oscillators with a center frequency of 100 MHz fabricated on $128^{\circ}$ Y-Z $LiNbO_{3}$ substrates. Experimental results, which show the phase change of output signal under the absorption of volatile gas onto sensors, are presented. The proposed sensor has the properties of high sensitivity compare to the conventional SAW gas sensor and chemical selectivity. Thus, it is thought these results are applicable for use in sensor array of an high performance electronic nose system.

• E2M - 전기 전자와 첨단 소재
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• 제8권4호
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• pp.509-517
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• 1995