• 제목/요약/키워드: Chemical sensor array

검색결과 55건 처리시간 0.028초

감지 패턴 인식에 의한 가스센서의 선택성 연구 (A Study on the Selectivity of Gas Sensors by Sensing Pattern Recognition)

  • 이성필
    • 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.

유클리디언 거리 기반의 단계적 소거 방법을 통한 화학센서 어레이 성능 최적화 (A Step-wise Elimination Method Based on Euclidean Distance for Performance Optimization Regarding to Chemical Sensor Array)

  • 임해진;최장식;전진영;변형기
    • 센서학회지
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    • 제24권4호
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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.

An Array-Based Sensor for Seafood Freshness Assessment

  • Gonzalez-Martin, Anuncia;Lewis, Brian;Raducanu, Marius;Kim, Jin-Seong
    • Bulletin of the Korean Chemical Society
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    • 제31권11호
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    • pp.3084-3092
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    • 2010
  • This paper describes the development of an automated, hand-held sensor for the fast assessment of seafood freshness. The sensor developed here combined: an array-based chemical sensor, composed of incrementally different conducting polymer elements deposited on a small chip; a highly sensitive, custom-made electronics for the detection of very small signal changes; precise temperature control of the sensor chamber; and an on-board microcontroller for data collection, storage, automation, and analysis. The instrument was used to successfully test seafood samples with different degree of freshness and spoilage. A linear relationship between microbiological count and e-Nose signal for three different fish fillet was developed. Once the linear relationship is included into the hand-held unit software, the e-Nose signal can be used for assessment of seafood freshness without performing the microbiological count technique.

대규모 가스 센서 어레이에서 중복도의 제거와 확률신경회로망을 이용한 분류 (The Classification Using Probabilistic Neural Network and Redundancy Reduction on Very Large Scaled Chemical Gas Sensor Array)

  • 김정도;임승주;박성대;변형기;;김정주
    • 센서학회지
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    • 제22권2호
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    • pp.162-173
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    • 2013
  • The purpose of this paper is to classify VOC gases by emulating the characteristics found in biological olfaction. For this purpose, we propose new signal processing method based a polymeric chemical sensor array consisting of 4096 sensors which is created by NEUROCHEM project. To remove unstable sensors generated in the manufacturing process of very large scaled chemical sensor array, we used discrete wavelet transformation and cosine similarity. And, to remove the supernumerary redundancy, we proposed the method of selecting candidates of representative sensor representing sensors with similar features by Fuzzy c-means algorithm. In addition, we proposed an improved algorithm for selecting representative sensors among candidates of representative sensors to better enhance classification ability. However, Classification for very large scaled sensor array has a great deal of time in process of learning because many sensors are used for learning though a redundancy is removed. Throughout experimental trials for classification, we confirmed the proposed method have an outstanding classification ability, at transient state as well as steady state.

Wilks Lamda 방법을 이용한 화학센서 어레이 최적화 (Chemical Sensors Array Optimization Based on Wilks Lamda Technique)

  • 전진영;유준부;신정숙;변형기
    • 센서학회지
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    • 제23권5호
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    • pp.299-304
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    • 2014
  • Optimizing the performance of a composite sensor array is necessary when the number of sensors to choose from is large. In this paper, we present a chemical sensors array optimization method using Wilks Lamda algorithm applicable a device to detect low concentration of alcohol from driver's exhale breath for interlocking engine ignition preventing drink-driving. More than 20 chemical sensors fabricated different synthetic stuffs and heater temperatures by collaborators were nominated, 5 sensors were selected for optimal sensors array using the method, and alcohol samples were well discriminated from the interference gases inside the vehicle. It has been confirmed by Principal Component Analysis (PCA).

Signal Processing Techniques Based on Adaptive Radial Basis Function Networks for Chemical Sensor Arrays

  • Byun, Hyung-Gi
    • 센서학회지
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    • 제25권3호
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    • pp.161-172
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    • 2016
  • The use of a chemical sensor array can help discriminate between chemicals when comparing one sample with another. The ability to classify pattern characteristics from relatively small pieces of information has led to growing interest in methods of sensor recognition. A variety of pattern recognition algorithms, including the adaptive radial basis function network (RBFN), may be applicable to gas and/ or odor classification. In this paper, we provide a broad review of approaches for various types of gas and/or odor identification techniques based on RBFN and drift compensation techniques caused by sensor poisoning and aging.

미소구조물의 표면온도 측정 및 제어를 위한 다이오드 온도 센서 어레이 설계 (Diode Temperature Sensor Array for Measuring and Controlling Micro Scale Surface Temperature)

  • 한일영;김성진
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1231-1235
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    • 2004
  • The needs of micro scale thermal detecting technique are increasing in biology and chemical industry. For example, Thermal finger print, Micro PCR(polymer chain reaction), ${\mu}TAS$ and so on. To satisfy these needs, we developed a DTSA(Diode Temperature Sensor Array) for detecting and controlling the temperature on small surface. The DTSA is fabricated by using VLSI technique. It consists of 32 ${\times}$ 32 array of diodes (1,024 diodes) for temperature detection and 8 heaters for temperature control on a 8mm ${\times}$ 8mm surface area. The working principle of temperature detection is that the forward voltage drop across a silicon diode is approximately proportional to the inverse of the absolute temperature of diode. And eight heaters ($1K{\Omega}$) made of poly-silicon are added onto a silicon wafer and controlled individually to maintain a uniform temperature distribution across the DTSA. Flip chip packaging used for easy connection of the DTSA. The circuitry for scanning and controlling DTSA are also developed

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소형전극 어레이로 구성한 흐름계형 전자혀 (Electronic Tongue Composed of Mini-Electrode Array in Flow Cell)

  • 심준호;심재훈;서성석;오현준;한종호;남학현;차근식
    • 분석과학
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    • 제17권3호
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    • pp.217-224
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    • 2004
  • 소형의 이온선택성 전극을 흐름계 어레이로 구성하여 전자혀 시스템을 제작하였다. 제작된 전자혀 시스템에 음용수 및 알코올성 음료를 저 농도의 완충용액 (0.005 M Tris-$H_2SO_4$ pH 7.2)에 묽힌 후 9개의 전극이 장착된 흐름계에 흘려 보내어 전위차를 측정하였다. 얻어진 자료는 주성분 분석 (principal component analysis; PCA)을 통하여 식음료의 맛을 평가할 수 있도록 2차원 및 3차원 좌표계에 표시하였다. 본 연구에서 제작한 전자혀 시스템은 식품의 생산공정관리의 목적으로 또는 시중에서 구할 수 있는 식음료 맛의 변화 추이를 구분해 내는 목적으로 유용하게 사용될 수 있다.

Sensor array optimization techniques for exhaled breath analysis to discriminate diabetics using an electronic nose

  • Jeon, Jin-Young;Choi, Jang-Sik;Yu, Joon-Boo;Lee, Hae-Ryong;Jang, Byoung Kuk;Byun, Hyung-Gi
    • ETRI Journal
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    • 제40권6호
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    • pp.802-812
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    • 2018
  • Disease discrimination using an electronic nose is achieved by measuring the presence of a specific gas contained in the exhaled breath of patients. Many studies have reported the presence of acetone in the breath of diabetic patients. These studies suggest that acetone can be used as a biomarker of diabetes, enabling diagnoses to be made by measuring acetone levels in exhaled breath. In this study, we perform a chemical sensor array optimization to improve the performance of an electronic nose system using Wilks' lambda, sensor selection based on a principal component (B4), and a stepwise elimination (SE) technique to detect the presence of acetone gas in human breath. By applying five different temperatures to four sensors fabricated from different synthetic materials, a total of 20 sensing combinations are created, and three sensing combinations are selected for the sensor array using optimization techniques. The measurements and analyses of the exhaled breath using the electronic nose system together with the optimized sensor array show that diabetic patients and control groups can be easily differentiated. The results are confirmed using principal component analysis (PCA).

Investigation of Chemical Sensor Array Optimization Methods for DADSS

  • Choi, Jang-Sik;Jeon, Jin-Young;Byun, Hyung-Gi
    • 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.