• 센서학회지
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• 제13권1호
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• pp.41-46
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• 2004

There is currently much interest in the development of instruments that emulate the senses of humans. Increasingly, there is demand for mimicking the human sense of smell, which is a sophisticated chemosensory system. An electronic nose system is applicable to a large area of industries including environmental monitoring. We have designed a protable electronic nose system using an array of commercial chemical gas sensors for recognizing and analyzing the various odours. In this paper, we have implemented a portable electronic nose system using an array of gas sensors for recognizing and analyzing VOCs (Volatile Organic Compounds) in the field. The accuracy of a portable electronic nose system may be lower than an instrument such as GC/MS (Gas Chromatography/Mass Spectrometer). However, a portable electronic nose system could be used on the field and showed fast response to pollutants in the field. Several different algorithms for odours recognition were used such as BP (Back-Propagation) or LM-BP (Levenberq-Marquardt Back-Propagation). We applied RBF (Radial Basis Function) Network for recognition and quantifying of odours, which has simpler and faster compared to the previously used algorithms such as BP and LM-BP.

• 농업과학연구
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• 제38권3호
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• pp.525-532
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• 2011

The aim of this study was to develop a portable electronic nose system for freshness measurement of meats, which could be an alterative of subjective measurements of human nose and time-consuming measurements of conventional gas chromatograph methods. The portable electronic system was o optimized by comparing the measurement sensitivity and hardware efficiency, such as power consumption and dimension reduction throughout two stages of the prototypes. The electronic nose systems were constructed using an array of four different metal oxide semiconductor sensors. Two different configurations of sensor array with dimension were designed and compared the performance respectively. The final prototype of the system showed much improved performance on saving power consumption and dimension reduction without decrease of measurement sensitivity of pork freshness. The results show the potential of constructing a portable electronic system for the measurement of meat quality with high sensitivity and energy efficiency.

• Journal of Biosystems Engineering
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• 제33권5호
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• pp.333-339
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• 2008

The purpose of this study was to develop a portable electronic nose system to measure volatile components of agricultural and food products. Also, a graphical operating software to control the electronic nose system and to acquire signals through the Internet was developed. An array of five commercial metal oxide gas sensors was used to detect various volatile gas components of target samples. Transient and steady state signals were analyzed to extract variables related to sample states, To find optimal operating conditions of the system, several experiments were performed with different gas chambers, vacuum pumps, gas sampling temperatures, and sample container sizes. The patterns of gas sensor signals were analysed to find effects of the various conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.39-42
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• 2004

We have designed a portable electronic nose(e-nose) system using an array of commercial gas sensors for recognition and analyzing the various odours. In this paper, we have implemented a portable e-nose system using an array gas sensors and personal digital assistants(PDA) for recognizing and analyzing volatile organic compounds(VOCs) in the field. Field screening for pollutants has been a target of instrumental development for number of year. A portable e-nose system can be substantial benefit to rapidly localize the spacial extent of a pollution or to find pollutants source. And, by using PDA, E-nose have a better function such as the easy user-interface and data transfer by internet from on- site to remote computer. We adapted the Levenberg-Marquardt algorithm based on the back-propagation and proposed the method that could be predicted concentration levels of VOCs gases after classification by separating neural network into two parts.

• 센서학회지
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• 제13권6호
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• pp.454-461
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• 2004

We have designed a portable electronic nose (e-nose) system using an array of commercial gas sensors and personal digital assistants (PDA) for the recognition and analysis of volatile organic compounds (VOC) in the field. Field screening of pollutants has been a target of instrumental development during the past years. A portable e-nose system was advantageous to localize the special extent of a pollution or to find pollutants source. The employment of PDA improved the user-interface and data transfer by Internet from on-site to remote computer. We adapted the Lavenberg-Marquardt algorithm based on the back-propagation and proposed the method that could predict the concentration levels of VOC gases after classification by separating neural network into two parts.

• 농업과학연구
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• 제38권4호
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• pp.761-767
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• 2011

The objective of this study was to predict total bacteria count of pork meats by using the portable electronic nose systems developed throughout two stages of the prototypes. Total bacteria counts were measured for pork meats stored at $4^{\circ}C$ for 21days and compared with the signals of the electronic nose systems. PLS(Partial least square), PCR (Principal component regression), MLR (Multiple linear regression) models were developed for the prediction of total bacteria count of pork meats. The coefficient of determination ($R_p{^2}$) and root mean square error of prediction (RMSEP) for the models were 0.789 and 0.784 log CFU/g with the 1st system for the pork loin, 0.796 and 0.597 log CFU/g with the 2nd system for the pork belly, and 0.661 and 0.576 log CFU/g with the 2nd system for the pork loin respectively. The results show that the developed electronic system has potential to predict total bacteria count of pork meats.

• 센서학회지
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• 제14권2호
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• pp.69-77
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• 2005

The electronic nose (e-nose) has been used in food industry and quality controls in plastic packaging. Recently it finds its applications in medical diagnosis, specifically on detection of diabetes, pulmonary or gastrointestinal problem, or infections by examining odors in the breath or tissues with its odor characterizing ability. Moreover, the use of portable e-nose enables the on-site measurements and analysis of vapors without extra gas-sampling units. This is expected to widen the application of the e-nose in various fields including point-of-care-test or e-health. In this study, a PDA-based portable e-nose was developed using micro-machined gas sensor array and miniaturized electronic interfaces. The rich capacities of the PDA in its computing power and various interfaces are expected to provide the rapid and application specific development of the diagnostic devices, and easy connection to other facilities through information technology (IT) infra. For performance verification of the developed portable e-nose system, Six different vapors were measured using the system. Seven different carbon-black polymer composites were used for the sensor array. The results showed the reproducibility of the measured data and the distinguishable patterns between the vapor species. Additionally, the application of two typical pattern recognition algorithms verified the possibility of the automatic vapor recognition from the portable measurements. These validated the portable e-nose based on PDA developed in this study.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.99-102
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• 1997

An electronic nose system is an instrument designed far mimicking human olfactory system. It consists generally of gas (odor) sensor array corresponding to olfactory receptors of human nose and artificial neural network pattern recognition technique based on human biological odor sensing mechanism. Considerable attempts to develop the electronic nose system have been made far applications in the fields of floods, drinks, cosmetics, environment monitoring, etc. A portable electronic nose system has been fabricated by using oxide semiconductor gas sensor array and pattern recognition technique such as principal component analysis (PCA) and back propagation artificial neural network The sensor array consists of six thick film gas sensors whose sensing layers are Pd-doped WO$_3$ Pt-doped SnO$_2$ TiO$_2$-Sb$_2$O$_3$-Pd-doped SnO$_2$ TiO$_2$-Sb$_2$O$_{5}$-Pd-doped SnO$_2$+Pd filter layer, A1$_2$O$_3$-doped ZnO and PdCl$_2$-doped SnO$_2$. As an application the system has been used to identify CO/HC car exhausting gases and the identification has been successfully demonstrated.d.

• 전자공학회논문지SC
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• 제48권2호
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• pp.64-70
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• 2011

휴대용 인공 전자 후각 시스템 (E-nose)의 가스 측정 환경은 실험실 내의 정교하게 제어되는 환경과 달리 온도, 농도, 기체 시료의 유속 등의 외부 요인의 변동이 매우 심하다. 이런 환경에서도 사용 가능한 단순하고 강인하고 정확한 가스 패턴 인식 알고리듬의 개발은 마이크로 바이오 센서의 발달과 함께 확대되고 있는 휴대용 및 소형 측정 진단 시스템에 있어 매우 중요하다. 본 연구에서는 PDA 기반의 휴대용 전자 후각 시스템을 활용해 실제 변화하는 환경에서 다채널 마이크로 센서로부터 감지되는 가스 신호를 수집하고, 여기에 영상 정합 기법을 적용하여 알고리듬의 강인성과 향상된 정확도를 검증하는 것을 목표로 하였다. 제안된 방법을 6종류의 가스 시료에 대한 7채널 마이크로 센서의 휴대 환경 측정 데이터에 적용하고, 기존의 최대 민감도 특징 추출 기법과 비교한 결과, 외부 환경의 변동에 영향 받지 않는 안정된 인식 성능 뿐 아니라 기존의 방법으로 구별하기 어렵던 2 종의 유사한 가스 시료에 대해서도 정확한 구분이 가능함을 보였다. 제안된 방법은 다양한 환경 변화에 노출되는 유비쿼터스 센서 네트워크 (USN)의 데이터 처리에도 쉽게 응용될 수 있을 것이며, 응용 현장에서 높은 안정성과 정확성을 요구하는 휴대용 의료 진단, 환경 감지 기술의 실용화에 큰 도움을 줄 수 있을 것으로 기대한다.

• 한국축산식품학회지
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• 제30권2호
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• pp.313-320
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• 2010

본 연구에서는 저장기간에 따른 계육의 신선도 변화를 GC-MS를 이용한 가스 성분의 변화, 미생물의 총균수와 지방 산패도의 변화를 통해 분석하고, MOS 센서와 수분센서를 기반으로 한 전자코 시스템을 구성하여, 계육의 품질 평가를 실시하였다. 계육의 GC-MS, 미생물, 지방 산패도를 이용한 품질의 측정결과 저장기간이 증가함에 따라 품질은 저하되었고, 저장기간이 5일 이후부터 급격한 품질의 저하를 나타내기 시작했다. 전자코 시스템을 이용한 실험결과, 그래프 분석을 이용하여 계육은 저장기간 초기부터 저장기간의 증가에 따라 선형적으로 저항값의 변화율이 감소함을 확인할 수 있었다. 전자코 센서의 신호를 이용하여 주성분 분석을 한 결과 저장일수에 따라 제1, 2주성분이 뚜렷이 구분됨을 확인할 수 있었다. 선형판별을 이용하여 분석한 결과 1일에서 19일까지 전체 분류 정확도가 92.5%였다. 저장 초기의 1일에서 5일까지의 데이터를 기반으로 선형판별분석을 한 경우 제1, 2판별함수를 이용할 경우 100%의 정확도를 보였다. 결론적으로 본 연구에서의 전자코를 이용한 계측과 주성분분석 및 선형판별분석법을 이용할 경우 냉장 저장된 계육의 신선도 변화가 예측 가능함을 확인할 수 있었다.