• 센서학회지
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• 제22권3호
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• pp.181-184
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• 2013

Highly ordered porous materials having mesopores in the walls of macropores showed improved adsorption dynamics results for VOC molecules, especially bulky molecules. These meso/macroporous mataerials were synthesized by the dual templating method, and mesopore and macropore size were controlled by adjusting the templates for each pore size regime. In the case of adsorption and desorption of small VOC molecules (toluene), although meso/macroporous MCM-41 with smaller mesopore size showed improved results, meso/macroporous SBA-15 with larger mesopore size was not improved regardless of the existence of macropores, since there was no limitation of movement through the larger mesopore. However, the adsorption dynamics of bulky VOC molecules (p-xylene) over meso/macroporous SBA-15 were drastically improved by increasing the macropore size.

• 센서학회지
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• 제22권4호
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• pp.249-255
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• 2013

Gas-sensor array technology, which has been much utilized in the field of food technology by the name of 'electronic nose' is drawing attention in diagnosing lung cancer based on the analysis of the exhaled human breath. Much understanding has been accomplished about the composition of the volatile organic compounds (VOCs) of the human exhaled breath, in spite of some variations depending on research groups due mainly to lack of the standardization of the sensing procedures. Since VOCs may be produced during the process of cellular metabolism, difference in the cellular metabolism between healthy cells and lung cancer cells are expected to be reflected on the composition variation of the exhaled VOCs. Several studies have attempted to apply the gas-sensor array technology to lung cancer analysis using many different types of sensors including metal oxide, carbon black-polymer composite, surface acoustic wave, and gold nanoparticles. In this mini-review VOC as biomarkers, sensor array technology and application of the array technology for the diagnosis of cancer disease have been described.

• 센서학회지
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• 제33권3호
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• pp.185-185
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• 2024

• 센서학회지
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• 제21권6호
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• pp.446-450
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• 2012

The important factors in sensors are sensitivity, selectivity, and response time. Oxide semiconductors are high sensitivity, fast response and the advantage of miniaturization. Zn-doped $SnO_2$ materials have been synthesized in order to improve the selectivity of the sensor. ZnO/$SnO_2$ crystals were prepared by a simple hydrothermal process and ultrasound pretreated hydrothermal process. ZnO/$SnO_2$ urchins were fabricated in the precursor solution with [$Zn^{2+}$]:[$Sn^{4+}$] ratio of 1:5 and rod structures were fabricated ratio of 1:1 and 1:3. Surface area ratio was increased by increasing the ratio of [$Sn^{4+}$]. The sensitivity of sensors were highest at the [$Zn^{2+}$]:[$Sn^{4+}$] ratio of 1:5 in ethanol, acetaldehyde, toluene, and nitric oxide.

• 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.

• 한국정밀공학회지
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• 제28권12호
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• pp.1372-1378
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• 2011

The smart air condition system is superior to conventional air condition system in the aspect of control accuracy, environmental preservation and it is foundation for intelligent vehicle such as electric vehicle, fuel cell vehicle. In this paper, failure analyses of smart air condition system will be performed and then sensor fusion technique will be proposed for fail safety of smart air condition system. A sensor fusion logic of air condition system by using CO sensor, $CO_2$ sensor and VOC, $NO_x$ sensor will be developed and simulated by fault injection simulation. The fusion technology of smart air condition system is generated in an experiment and a performance analysis is conducted with fusion algorithms. The proposed algorithm adds the error characteristic of each sensor as a conditional probability value, and ensures greater accuracy by performing the track fusion with the sensors with the most reliable performance.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.250-252
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• 2002

The goals of environmental monitoring are to locate and quantify the significant contamination, estimate the fate and transport, estimate the potential exposure and risks to humans and the environment, and track the performance of various remedial technologies. In this study, ceramic gas sensor system is proposed to enhance the effectiveness of soil vapor extraction (SVE) process by monitoring the effluent gas. SVE is a technique that is widely used to remediate unsaturated soils contaminated with volatile organic contaminants. The sensor response for benzene, toluene, and xylene, the representative effluent gas compositions of SVE process, was evaluated using the proposed sensor system. As a result, it was verified that the response of sensor was increased or decreased very sensitively according to the change of the effluent gas concentration. Besides, the sensor could detect the difference over a wide range of concentration and it was more sensitive in order of xylene, toluene, and benzene. It is expected that this VOC analysis method results in field monitoring costs saying and appropriate immediate action for process control. More detailed experiments are being conducted in our research group.

• 대한의용생체공학회:의공학회지
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• 제25권5호
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• pp.329-334
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• 2004

전자후각(I-nose)시스템은, 전통적으로 음식물이나 플라스틱 제재의 생산에서 자동화된 품질관리 시스템에 사용되어 왔으나, 최근 호흡가스 등을 통해 당뇨, 호흡 및 소화기 질환과 감염 등을 검사하는 진단영역으로 그 응용분야를 확대하고 있다 이러한 질병과 연관이 없는 휘발성 유기화합물(volatile organic compound, YOC) 에 대하여 I-nose 의 센서어래이는 센서 물질과 휘발성 화합물 사이의 반응으로 인해 고유한 반응을 보이며, 신호의 profile 에 그 흔적을 남긴다. 본 연구에서는 센서어래이의 반응 신호를 profile 형태로 유지 및 분석함으로써 I-nose 의 가스시료 인식 성능을 보다 향상시킬 수 있는 방법을 제안하였다. 신호의 profile 에는 패턴인식을 위한 기존의 개별적인 특성(feature) 보다 많은 정보가 들어 있으며, 이를 가스의 구분에 효과적으로 이용하기 위해 디지털 영상처리에서 사용되는 패턴 매칭을 응용한time-profile방법을 새롭게 제안하였다. 제안된 방법의 검증을 위해, 반도체 공정에 의해 제작된 16채널의 초소형 가스센서 어래이를 사용해 측정된 8종류의 각기 다른 가스시료들에 대하여, 동종 및 이종 가스간의 매칭의 정도를 산출하였다. 기존의 방법과 비교한 결과 동종과 이종 가스간의 뚜렷한 구별이 가능하여 이를 패턴인식에 사용하면 E-nose의 가스 인식 성능을 향상시킬 것으로 전망된다.

• 신재생에너지
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• 제5권3호
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• pp.22-25
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• 2009

For increasing the output voltage, six SMD(surface mount device) type AlGaAs/GaAs solar cells were connected in series. The electrical properties of the array were measured and compared with one sun (100 mW/$cm^2$) and indoor light (480 lux) conditions. Under one sun condition, output power was 21.57 mW and it was $14.67\;{\mu}W$ under indoor light condition. Under the indoor light condition, the intensity of the light is very low compared to one sun condition. Thus the Voc(open circuit voltage) and Isc (short circuit current) of the sample under indoor light condition decreased very much compared to that of under the one sun condition. This kind of solar cell power supply can be used as a power source for ubiquitous sensor network (USN).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.405-405
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• 2000

We designed the artificial olfactory sensing system (Electronic Nose) using MOS type sensor array fur recognizing and analyzing odour. The response of individual sensors of sensor array, each processing a slightly different response towards the sample volatiles, can provide enough information to discriminate between sample odours. In this paper, we applied clustering algorithm for dimension reduction, such as linear projection mapping (PCA method), nonlinear mapping (Sammon mapping method) and the combination of PCA and Sammon mapping having a better discriminating ability. The odours used are VOC (Volatile chemical compound) and Toxic gases.