• Journal of Industrial Technology
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• v.33 no.A
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• pp.67-72
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• 2013

CNT(carbon nanotube) humidity sensors with plasma treated electrodes exhibit a much faster response time and a higher sensitivity to humidity, compared to untreated CNT and porous Cr electrodes. These results may be partially due to their percolated pore structure being more accessible for water molecules and for expending the diffusion of moisture to the polyimide sensing film, and partially due to the oxygenated surface of CNT films. This paper shows a plasma process effect and selectivity characteristics of CNT film humidity sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.129-133
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• 1993

$TiO_2-V_2O_5-Nb_2O_5$ humidity sensors have been fabricated in the ceramic type and their physical and hygroscopic characteristics have been investigated. The additives and sintering conditions affect the humidity sensitivity. XRD patterns, SEM photographs were used for the analysis of crystal structures and surface morphology. $TiO_2-V_2O_5-Nb_2O_5$ humidity sensors had good linearity in the range from 20%RH to 90%RH and the sensitivity of sensor sintered at $1,000^{\circ}C$ for 1hr was 73% at operating temperature $60^{\circ}C$.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.31-36
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• 2014

In this paper, we developed an intergrated piezoresistive temperature and humidity sensor using nano-technology, and evaluated the properties. In the measuring range from $20^{\circ}C$ to $80^{\circ}C$, output sensitivity of temperature was about 0.75mV/$1^{\circ}C$. Output sensitivity of humidity was about 1.35mV/10%(RH). Therefore, developed sensor suggests that it is possible applicable to the general residential environment.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.26-30
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• 2006

For the purpose of developing capacitive humidity sensor having interdigital electrodes, interdigital electrode was modeled and simulated to obtain capacitance and sensitivity as a function of geometric parameters like the structural gap and thickness. For the development of ASIC, switched capacitor signal processing circuits for capacitive humidity sensor were designed and simulated by Cadence using $0.25{\mu}m$ CMOS process parameters. The signal processing circuits are composed of amplifier for voltage gain control, and clock generator for sensor driving and switch control. The characteristics of the fabricated sensors are; 1) sensitivity is 9fF/%R.H., 2) temperature coefficient of offset(TCO) is $0.4%R.H./^{\circ}C$, 3) nonlinearity is 1.2%FS, 4) hysteresis is 1.5%FS in humidity range of $3%R.H.{\sim}98%R.H.$. The response time is 50 seconds in adsorption and 70 seconds in desorption. Fabricated process used in this capacitive humidity sensor having interdigital electrode are just as similar as conventional IC process technology. Therefore this can be easily mass produced with low cost, simple circuit and utilized in many applications for both industrial and environmental measurement and control system, such as monitoring system of environment, automobile, displayer, IC process room, and laboratory etc.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.3
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• pp.144-148
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• 2001

For the purpose of developing capacitive humidity sensor having interdigit electrodes, interdigit electrode was modeled and simulated to obtain capacitance and sensitivity as a function of geometric parameters like the structural gap and thichness. For the development of ASIC, switched capacitor signal conditioning circuits for capacitive humidity sensor were designed and simulated by cadence using 0.25um CMOS process parameters. The signal conditioning circuits are composed of amplifier for voltage gain control, and clock generator for sensor driving and switch control The characteristics of the fabricated sensors are; 1) sensitivity is 9fF/%R.H., 2) temperature coefficient of offset(TCO) is 0.4%R.H./$^{\circ}C$, 3) nonlinearity is 1.2%FS, 4) hysteresis is 1.5%FS in humidity range of 3%R.H. ${\sim}$ 98%R.H.. The response time is 50 seconds in adsorption and 70 seconds in desorption. Fabricated process used in this capacitive humidity sensor having interdigit electrode are just as similar as conventional IC process technology. Therefore this can be easily mass produced with low cost, simple circuit and utilized in many applications for both industrial and environmental measurement and control system, such as monitoring system of environment, automobile, displayer, IC process room, and laboratory etc..

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2871-2876
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• 2022

The sensitivity of polymer-based capacitive relative humidity (RH) sensors after irradiation with neutrons, electrons and protons was measured. Degradation consists of the decreasing of the upper RH limit that can be measured. At the same time, low RH-level sensitivity is almost stable. After 30 krad of absorption dose, RH cut off is equal to 85% of max value, after 60 krad-40%. Degradation reduces after annealing which indicates high radiation sensitivity of the internal circuit in comparison to RH-sensing polymer film.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.4
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• pp.70-76
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• 1994

A humidity sensing device based on a new humidity sensing principle is designed and fabricated in this study. The silicon thermopile is consisted of 25 couples of p-type diffused layer/Al strips. The internal resistance and the Seebeck coefficient are 300kl and 537$\mu$V/K, respectively Fabricated sensors showed linear response characteristics proportional to relative humidity changes with a sensitivity of 9$\mu$V/%RH in the range from 20% to 90%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.314-320
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• 2021

Controlling ambient humid condition through high performance humidity sensors has become important for various fields, including industrial process, food storage, and the preservation of historic remains. Although aerosol deposited humidity sensors using ceramic BaTiO₃ (BT) material have been widely studied because of their longtime stability, there remain critical disadvantages, such as low sensitivity, low linearity, and slow response/recovery time in case of the sensors fabricated at room temperature. To achieve superior humidity sensing properties even at room temperature condition, BT-Cu composite films utilizing aerosol deposition (AD) process have been proposed based on the percolation theory. The BT-Cu composite films showed gradually improved sensing properties until the Cu concentration reached 15 wt% in the composite film. However, the excessive Cu (above 30 wt%) containing BT-Cu composite films showed a rapid decrease of the sensing properties. The results of observed surface morphology of the AD fabricated composite films, to figure out the metal filler effect, showed correlation between surface topography as well as size and the amount of open pores according to the metal filler content. Overall, it is very important not only dielectric constant of the humidity sensing films but also microstructures, because they affect either the variation range of capacitance by ambient humidity or adsorption/desorption of ambient humidity onto/from the humidity sensing films.

• Journal of Sensor Science and Technology
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• v.13 no.4
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• pp.287-291
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• 2004

A capacitive type humidity sensor has been fabricated using a polyimide film without hydrophobic elements and its characteristics has been evaluated for hermeticity measurement of micro packages. For a highly sensitive humidity sensor, a polyimide film without hydrophobic elements has been synthesized and used instead of using a commercial one in which 7 group elements such as fluorine or chlorine are included. Sensitivity, stability and hysteresis has been performed to characterize the fabricated sensors. The sensitivity defined as normalized percent capacitance change was 0.3751%RH and hysteresis was 0.77% in the range of 10%RH to 90%RH. Maximum deviation from the average capacitance measured for 120 minutes at 50%RH was 0.25%. The proposed humidity sensor can be used for hermeticity measurement of micro packages.

• Journal of Environmental Impact Assessment
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• v.12 no.4
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• pp.271-279
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• 2003

Temperature and humidity forecasting have been performed using artificial neural networks model(ANN). We composed ANN with multi-layer perceptron which is 2 input layers, 2 hidden layers and 1 output layer. Back propagation algorithm was used to train the ANN. 6 nodes and 12 nodes in the middle layers were appropriate to the temperature model for training. And 9 nodes and 6 nodes were also appropriate to the humidity model respectively. 90% of the all data was used learning set, and the extra 10% was used to model verification. In the case of temperature, average temperature before 15 minute and humidity at present constituted input layer, and temperature at present constituted out-layer and humidity model was vice versa. The sensitivity analysis revealed that previous value data contributed to forecasting target value than the other variable. Temperature was pseudo-linearly related to the previous 15 minute average value. We confirmed that ANN with multi-layer perceptron could support pollutant dispersion model by computing meterological data at real time.