Suwalak, Rattapong
Loading...
Preferred name
Suwalak, Rattapong
Alternative Name
Suwalak, R.
Main Affiliation
Email
rattapong.su@kmitl.ac.th
31 results
Now showing 1 - 10 of 31
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Non-destructive determination of coconut oil using microwave dielectric constant sensing(2019-01-01); Coconut oil demand for food, medical and cosmetic uses is increasing. Analyses of quality using non-destructive tools would be useful, and therefore, wireless sensing using high frequency to determine the percentage of coconut oil has been tested. The proposed sensing is based on the wireless power transmission and the penetration of the ultrahigh frequency wave. The system operates with the microwave transceiver that generates wireless power and receives the backscatter power from a sensor placed on a coconut. A transceiver at microwave frequency of 920-925 MHz with low power level was used to avoid affecting coconut quality. Wireless microwave dielectric constant sensing was used with reasonable accuracy to determine the percentage of the coconut oil. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dual-Band Band-Stop Filter for Chipless RFID Sensor in a Dielectric Constant Determination(2022-01-01); ; Torrungrueng, DanaiThis paper presents the dual-band band-stop filter to operate with the chipless RFID tag acts as the RFID sensor for a dielectric constant determination and the identification characteristic based on the signature responded signal from the chipless RFID sensor system. The proposed dual-band filter can generate the dual-stop band of the frequency of 2.2 GHz and 2.7 GHz. The 3-bits identification (ID) i.e., ID-01, ID-10, and ID-11 are obtained from the proposed filter. In addition, the chipless RFID sensor with band-stop filter technique can be determined the dielectric constant of RT/Duroid5880, Fr4 (Glass Epoxy), and low-Temperature cofired ceramic (LTCC). - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Parametric study of a circularly polarized planar antenna for reader of UHF RFID system(2007-12-01); This paper presents the design of circularly polarized elliptical patch antenna (EPA) that radiates unidirectional beam. A circularly polarized patch antenna was investigated for the reader of the Radio Frequency Identification (RFID) at Ultra High Frequency (UHF) band. The center frequency is 923 MHz with the bandwidth from 920 MHz to 925 MHz. The antenna structure is simple because we use the single feed for circular polarization. The prototype antenna was fabricated to measure the antenna characteristics. The pattern is unidirectional pattern with directivity of 8.93 dBi and axial ratio of 1.88 dB at the center frequency. The obtained bandwidth is 15 MHz. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Determination of dielectric property of construction material products using a novel RFID sensor(2012-01-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A two-square-aperture antenna excited by a probe on rectangular ground plane with elliptical parasitic patch for UHF-RFID reader(2008-10-06); This paper presents a two-square-aperture antenna excited by a probe on rectangular ground plane with elliptical parasitic patch to radiate circularly polarized unidirectional beam. This antenna is proposed for installing at the reader of the Radio Frequency Identification (RFID) at ultra High Frequency (UHF) band. The UHF-RFID has the bandwidth from 920 MHz to 925 MHz, and the center frequency is 923 MHz. The antenna structure is simple because of using the single probe to feed the aperture antenna for circular polarized radiation. The pattern is unidirectional beam with the directivity of 8.93 dBic and axial ratio of 0.10 dB at the center frequency. The obtained simulated bandwidth is 24 MHz. ©2008 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Machine learning-based prediction of nutritional status in oil palm leaves using proximal multispectral images(2022-07-01); ; ; This study evaluated the application of proximal multispectral images accompanied by 4 machine learning approaches for estimating the nutritional status of oil palm leaves. The image responded for five bands: blue, green, red, red edge, and near-infrared regions with a center wavelength of 475, 560, 668, 717, and 840 nm. Average and standard deviation (SD) values from the leaf pixels of each band were extracted, obtaining 5 average and 5 SD values from 5 bands. Thirty-four vegetation variables were generated based on those average and SD values. In total, forty-four variables consisted of 10 average-and SD-based features, and 34 vegetation variables were used as the input candidates for analyses against 10 target variables: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), boron (B), and chlorophyll (SPAD). No significant input came out for modeling with P and Zn based on the stepwise selection. Therefore, 8 nutritional models were proposed in this study. A training set with 50 samples was used to be modeled for each target, and a test set with 15 samples was employed to evaluate the models' performances. Based on random forest (RF), support vector regression (SVR), partial least square regression (PLSR), and artificial neuron network (ANN) applied to be modeled, the models for chlorophyll, N, and Ca predictions were acceptable for screening, and those for K and Mg predictions were acceptable for rough screening. The chlorophyll model developed based on the RF had the predictive statistics in terms of coefficient of determination for prediction (r<sup>2</sup>), root mean square error of prediction (RMSEP), and standard error of prediction (SEP) of 0.752, 5.46 SPAD, and 5.65 SPAD, respectively. The other 2 screening models developed based on SVR and RF for N and Ca, respectively, gave the performances with the r<sup>2</sup>, RMSEP, and SEP ranging from 0.655 to 0.718, 0.12 to 0.17%, and 0.12 to 0.18%, respectively. In the case of the 2 rough screening models established using the RF algorithm, the predictive statistics ranged from 0.496 to 0.530 for the r<sup>2</sup> and 0.07–0.16% for both RMSEP and SEP. In this study, the Fe, Mn, and B models had poor results presenting the range of r<sup>2</sup>, RMSEP, and SEP of 0.308–0.491, 2.39–72.9 ppm, and 2.45–62.8 ppm, respectively. Based on the results, this study confirmed that the proximal multispectral information of oil palm leaves had enough significance to account for the status of chlorophyll and macro-nutrients: N, K, Ca, and Mg in the leaves. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dual-band RFID-reader antenna using annular plate with curved and rectangular slots(2010-12-01); A dual-band antenna for the reader of the Radio Frequency Identification (RFID) applications is proposed. The antenna design to achieve the dual-frequency band is carried out by using the annular plate with curved and rectangular slots. The simulation is done by using CST based on the Finite Integral Method. Furthermore, the parameters of antenna are optimized with the Quasi Newton method. The effects of antenna parameters are analyzed. Along the UHF-RFID band, the pattern is unidirectional beam. The half-power beamwidths in xz- and yz- planes are 78 and 64 degrees, respectively. The bandwidth covers 911-925.6 MHz. The directivity is 8.33 dBi. For 2.45 GHz band, the pattern is also unidirectional beam. The half-power beamwidths in xz- and yz-planes are 58 and 21 degrees, respectively. The bandwidth covers 2.32-2.52 GHz. The gain is 9-10.5 dBi. ©2010 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Statistical characteristic measurements of propagation in durian orchard for sensor network at 5.8 GHz(2008-12-01); ; The statistical characteristic measurement results of wireless sensor network in durian orchard at 5.8 GHz are presented. The measurement results are performed to study the channel characteristic of the radio wave propagation in the durian orchard. The communication channel is connected from sensor node to communication node and between communication node. The transmitter is setup at the bole of a durian tree for one communication node, and the received power by spectrum analyzer is used for the other communication node. Moreover, the transmitter is setup on the branch of durian tree for the sensor node placed on a durian. The signal strength is measured by spectrum analyzer. The sampling time of two seconds is employed to collect the signal strength for histogram plot. The statistical models, such as the Rican distribution and normal distribution are employed to fit the measurement results. These results can be used to approximate the statistical channel characteristics to predict the bit error rate in the wireless sensor network systems in durian orchard at 5.8 GHz. © 2008 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Circularly polarized truncated planar antenna with single feed for UHF RFID reader(2007-12-01); This paper presents truncated planar antenna that radiates unidirectional beam with circular polarization. This antenna is proposed for installing at the reader of the Radio Frequency Identification (RFID) at Ultra High Frequency (UHF) band. The center frequency is 923 MHz with the bandwidth from 920 MHz to 925 MHz. The antenna structure is simple because we use the single feed for circular polarization. The prototype antenna was fabricated to measure the characteristics. The pattern is unidirectional pattern with directivity around 8.92 dBi and axial ratio of 1.73 dB at the center frequency. The obtained bandwidth is 16 MHz. ©2007 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Flexible Chipless RFID Sensor for permittivity sensing of Cylindrical Impedance Surface(2023-01-01); ;