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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Sensor Science and Technology
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Journal DOI :
The Korean Sensors Society
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Volume & Issues
Volume 20, Issue 6 - Nov 2011
Volume 20, Issue 5 - Sep 2011
Volume 20, Issue 4 - Jul 2011
Volume 20, Issue 3 - May 2011
Volume 20, Issue 2 - Mar 2011
Volume 20, Issue 1 - Jan 2011
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Fabrication and Characteristics of Micro-Electro-Mechanical-System-Based Gas Flow Sensor
Choi, Ju-Chan ; Lee, June-Kyoo ; Kong, Seong-Ho ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 363~367
DOI : 10.5369/JSST.2011.20.6.363
This paper proposes a highly-sensitive gas flow sensor with a simple structure. The sensor is composed of a micro-heater for heating the gas medium and a pair of temperature sensors for detecting temperature differences due to gas flow in a sealed chamber on one axis. Operation of the gas flow sensor depends on the transfer of heat through the air medium. The proposed gas flow sensor has the capability to measure gas flow rates <5
/min with a resolution of approximately 0.01
/min. Furthermore, this paper reports some additional experiment results, including the sensitivity of the proposed gas flow sensor as a function of operating current and the flow of different types of gas(oxygen, carbon dioxide, and nitrogen). The fabrication process of the proposed sensor is very simple, making it a good candidate for mass production.
Real-Time Detection of Residual Free Chlorine and pH in Water Using a Microchannel Device
Kim, Sam-Hwan ; Choi, Ju-Chan ; Lee, June-Kyoo ; Kong, Seong-Ho ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 368~374
DOI : 10.5369/JSST.2011.20.6.368
A microfluidic device for real-time monitoring of residual free chlorine and pH in water based on optical absorption is proposed. The device consists of a serpentine micromixer for mixing samples with a reagent, and a photodiode and light emitting diode(LED) for the detection of light absorbance at specific wavelengths, determined for specific reagent combinations. Spectral analyses of the samples mixed with N, N'-diethyl-p-phenylenediamine(DPD) reagent for chlorine determination and bromothymol blue(BTB) for pH measurement are performed, and the wavelengths providing the most useful linear changes in absorbance with chlorine concentration and pH are determined and used to select the combination of LED and photodiode wavelengths for each analyte. In tests using standard solutions, the device is shown to give highly reproducible results, demonstrating the feasibility of the device for the inexpensive and continuous monitoring of water quality parameters with very low reagent consumption.
Modeling of IPMC (Ionic Polymer-Metal Composite) Sensor to Effectively Detect the Bending Angles of a Body
Park, Ki-Won ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 375~381
DOI : 10.5369/JSST.2011.20.6.375
Ionic polymer-metal composite(IPMC) consists of an ion conductive membrane plated by metallic electrodes on both surfaces. When it bends, a voltage is generated between two electrodes. Since IPMC is flexible and thin, it can be easily mounted on the various surfaces of a body. The present study investigates a sensor system using IPMC to effectively detect the bending angles applied on IPMC sensor. The paper evaluates several R and C circuit models that describe the physical composition of IPMC and selects the best model for the detection of angles. The circuit models implemented with a charge model describe the relationship between input bending angles and output voltages. The identification of R and C values was performed by minimizing the error between the real output voltages and the simulated output voltages from the circuit models of IPMC sensor. Then the output signal of a sensor was fed into the inverse model of the identified model to reproduce the bending angles. In order to support the validation of the model, the output voltages from an arbitrary bending motion were also applied to the selected inverse model, which successfully reproduced the arbitrary bending motion.
Real Time Drowsiness Detection by a WSN based Wearable ECG Measurement System
Takalokastari, Tiina ; Jung, Sang-Joong ; Lee, Duk-Dong ; Chung, Wan-Young ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 382~387
DOI : 10.5369/JSST.2011.20.6.382
Whether a person is feeling sleepy or reasonably awake is important safety information in many areas, such as humans operating in traffic or in heavy industry. The changes of body signals have been mostly researched by looking at electroencephalogram(EEG) signals but more and more other medical signals are being examined. In our study, an electrocardiogram(ECG) signal is measured at a sampling rate of 100 Hz and used to try to distinguish the possible differences in signal between the two states: awake and drowsy. Practical tests are conducted using a wireless sensor node connected to a wearable ECG sensor, and an ECG signal is transmitted wirelessly to a base station connected to a server PC. Through the QRS complex in the ECG analysis it is possible to obtain much information that is helpful for diagnosing different types of cardiovascular disease. A program is made with MATLAB for digital signal filtering and graphing as well as recognizing the parts of the QRS complex within the signal. Drowsiness detection is performed by evaluating the R peaks, R-R interval, interval between R and S peaks and the duration of the QRS complex..
Face Detection for Interactive TV Control System in Near Infra-Red Images
Won, Chul-Ho ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 388~392
DOI : 10.5369/JSST.2011.20.6.388
In this paper, a face detection method for interactive TV control system using a new feature, edge histogram feature, with a support vector machine(SVM) in the near-infrared(NIR) images is proposed. The edge histogram feature is extracted using 16-directional edge intensity and a histogram. Compared to the previous method using local binary pattern(LBP) feature, the proposed method using edge histogram feature has better performance in both smaller feature size and lower equal error rate(EER) for face detection experiments in NIR databases.
Air Flow Sensor with Corrugation Structure for Low Air Velocity Detection
Choi, Dae-Keun ; Lee, Sang-Hoon ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 393~399
DOI : 10.5369/JSST.2011.20.6.393
In this paper, we designed and fabricated the novel air flow sensor using air drag force, which can be applied to the low air flow detection. To measure the low air flow, we should enlarge the air drag force and the output signal at the given air flow. The paddle structure is applied to the device, and the device is vertically located against the air flow to magnify the air drag force. We also adapt the corrugation structure to improve the output signals on the given air velocity. The device structure is made up of the silicon nitride layer and the output signal is measured with the piezoresistive layer. The output signals from the corrugated device show the better measurement sensitivity and the response time than that of flat one. The repeated measurement also shows the stabilized signals.
Development of Disposable Enzyme-linked Immunosensor Strip Platform
Choi, Ji-Hye ; Yi, Seung-Jae ; Chang, Seung-Cheol ; Kim, Kyung-Chun ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 400~405
DOI : 10.5369/JSST.2011.20.6.400
This study introduced the development of a strip type disposable enzyme-linked immunosensor platform for the detection of IgG. Strips of the strip sensor were fabricated by using commercial nitrocellulose filter membranes and a housing holder for the strips was manufactured by using a standard injection molding process for a plastic material. An IgG-urease conjugate was prepared and used for the competitive immune-binding with sample IgG. From the enzymatic reaction between the conjugated urease and urea added, ammonia was generated and caused a localized alkaline pH change on the immobilized antibody band which was coated onto the sensor strips. This pH increase subsequently caused a color change of the antibody band in the presence of a pH indicator, phenol red. Used in conjunction with a competitive immunoassay format, the intensity of the color produced is directly linked with the concentration of target analyte, IgG, and specific measurement of IgG in a lateral flow immunoassay format was achieved over the range 100 ppb to 2000 ppb IgG.
The Gas Sensing Properties of Thick Film Gas Sensor Using Co
Powder Prepared by Hydrothermal Reaction Method
Kim, Kwang-Hee ; Kim, Jeong-Gyoo ; Park, Ki-Cheol ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 406~411
DOI : 10.5369/JSST.2011.20.6.406
thick film gas sensor using the powder prepared by hydrothermal reaction method(HRM) was fabricated. For comparison study, we also prepared the sensor using commercial
powder under the same fabrication conditions. Sensitivity, time response, and selectivity of them to variable gases such as iso-
were investigated. The sensor from the powder prepared by HRM showed higher sensitivity to every gas than those from commercial powder. For iso-
gas, the sensitivities of both sensor to 100 ppm are 160 % and 40 %, respectively. Time response and selectivity of the sensor using the powder prepared by HRM were better than those of the sensor using commercial powder.
Reducing the Effects of Noise Light Using Inter-Bit Noise Detection in a Visible Light Identification System
Hwang, Da-Hyun ; Lee, Seong-Ho ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 412~419
DOI : 10.5369/JSST.2011.20.6.412
In this paper, we used the inter-bit noise detection method in order to reduce the effects of noise light in a visible light identification system that uses a visible LED as a carrier source. A visible light identification system consists of a reader and a transponder. When the enable signal from the reader is detected, the transponder encodes the response data in RZ(Return-to-Zero) bit stream and sends response signal by modulating a visible LED. The reader detects the response signal mixed with noise light, samples the noise voltage in each blank low time between data bits of the RZ signal, and recovers the original data by subtracting the sampled noise from the received signal. In experiments, we improved the signal-to-noise ratio by 20dB using the inter-bit noise detection method.
Telemonitoring System of Fall Detection for the Elderly
Lee, Yong-Gyu ; Cheon, Dae-Jin ; Yoon, Gil-Won ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 420~427
DOI : 10.5369/JSST.2011.20.6.420
The population of elderly people increases rapidly as our society moves towards the aged one. Healthcare for the elderly becomes an important issue and falling down is one of the critical problems although not well recognized. In this study, a fall detection system was developed using a 3-axis accelerometer. Analyzing fall patterns, we took into account the degree of impact, posture angle, the repetitions of similar movements and the activities after a potential fall and proposed an algorithm of fall detection. Information of the fall sensor was sent to a remote healthcare server through the wireless networks of Zigbee and WLAN. Our system was designed to monitor multiples users. 12 persons participated in experiment and each one performed 24 different movements. Our proposed algorithm was compared with other reported ones. Our method produced the excellent results having a sensitivity of 96.4 % and a specificity of 100 % whereas other methods had a sensitivity range between 87.5 % and 94.8 % and a specificity range between 63.5 % and 83.3 %.
A Study on the Selectivity of Gas Sensors by Sensing Pattern Recognition
Lee, Sung-Pil ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 428~433
DOI : 10.5369/JSST.2011.20.6.428
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
CMOS technology, and unique gas sensing patterns were obtained by principal component analysis from the array.
/Pt sensor for CO gas showed a high selectivity to buthane gas and humidity.
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.
Detection of IgG Using Thiolated Protein G Modified SPR Sensor Chip
Sin, Eun-Jung ; Lee, Yeon-Kyung ; Sohn, Young-Soo ;
Journal of Sensor Science and Technology , volume 20, issue 6, 2011, Pages 434~438
DOI : 10.5369/JSST.2011.20.6.434
A portable surface plasmon resonance(SPR) based immunosensor using thiolated protein G and protein G was developed for the detection of immunoglobulin G(IgG). The protein G has specific affinity with Fc fragment of IgG and was thiolated by 2-Iminothiolane for introduction of thiol groups. Anti-IgG, bovine serum albumin(BSA), and IgG have been sequently injected after surface modification of gold sensor chip with protein G and thiolated protein G. The output signal was increased with the injection of each protein and the actual signal was measured by subtracting signal of reference channel from signal of sample injected channel. The experimental results showed the higher detection capability of IgG using thiolated protein G compared with protein G. From these results, we can conclude that the current surface modification technique and the portable SPR sensor system can be applied to various immunosensors for diagnosis.