Wardkein, Paramote
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Wardkein, Paramote
Alternative Name
Wardkein, P.
Wardkein, Pramote
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Email
paramote.wa@kmitl.ac.th
135 results
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Item type:Publication, Phase noise phenomenon explanation based multi-time variables differential equation technique(2016-09-06); In this article, the mathematical analysis is proposed to describe phase noise phenomenon. The principle of this proposed scheme is based on the multi-time variables differential equation technique. The analytic result clearly shows that noise is composed of multiplicative noise that spread around an oscillated frequency and additive noise acts as a noise floor of a system. To verify the proposed analysis, the computer simulation results are given which demonstrate that the obtained results agree well with the theoretical counterpart. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Direct frequency estimation based adaptive algorithm for a second-order adaptive FIR notch filter(2008-02-01); This work deals with the problem of the frequency estimation of a sinusoidal signal corrupted by broad-band noise. The direct frequency estimation based adaptive algorithm for a second-order adaptive finite impulse response (FIR) notch filter (AFNF) is thus proposed. The proposed algorithm employs the bias removal technique to remove the bias existing in the estimated parameter. The performances including the rate of convergence and the mean square error (MSE) can be easily controlled by using only one parameter, i.e., step size parameter. Moreover, the proposed filter is simple to implement and suitable for real-time applications. In addition, the difference equations for the convergence in the mean and mean square, and the closed form expressions for the steady-state estimation bias and MSE are also carried out. Finally, the simulation results are provided to confirm the theoretical analysis. © 2007 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Modified adaptive IIR notch filter based on direct frequency estimation algorithm(2006-12-01); A modified adaptive IIR notch filter based on direct frequency estimation algorithm is presented. The proposed system uses the automatic gain control and the Kalman filtering technique to improve the convergence speed and reduce the steady-state mean square error (MSE) of the estimated frequency. The simulation results confirm that the performance of the proposed system has been improved over the conventional direct and indirect adaptive IIR notch filters. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A novel versatile modulator circuit(2005-12-01); ; In this paper, a novel versatile modulator that can function either as delta modulator, sigma-delta modulator, amplitude modulator and frequency modulator is proposed. The principle of the proposed scheme is based on schmitt-trigger circuit and composed of a few components: three OTAs, one capacitor and two resistors. The advantage of this circuit is that the clock (carrier) signal employed for modulation is inherent in the circuit. The modulating signal is therefore an external input requirement. Based on the compactness of the circuit, it is suitable for IC realization. The computer simulation demonstrates the results which agree well with the theoretical analysis. © 2005 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Chainsaw location finding based on travelling of sound wave in air and ground(2020-04-08) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A Photoplethysmographic Signal Isolated from an Additive Motion Artifact by Frequency Translation(2018-08-01); Acquiring a precise percentage of oxygen saturation (SpO2) from a finger-probe pulse oximeter is dependent on both artifact-free red and infrared photoplethysmoghaphic (PPG) signals. Nonetheless, in real-life situations, these PPG signals are corrupted by a motion artifact (MA) signal that is generated from either finger or hand movement. To resolve this MA interference, the cause of the adulteration of PPG signals by the MA signal is examined. The MA signal is found to behave like an additive noise. Additionally, the frequency responses of the MA and PPG signals show that these signals are in the same frequency band. Hence, instead of direct current, a sinusoidal wave alternating current is proposed to drive an LED source in order to shift the PPG frequency band away from the MA frequency band. Experimentally, a commercial finger-probe pulse oximeter is employed. To determine the performance of the presented scheme, the resulting PPG signals are compared with those from employing the old-fashioned LED-driving method. In addition, the accuracy is verified by computing the SpO2 value. The results reveal that the proposed approach successfully retains the fundamental morphologies of the PPG structures when motion occurs. Moreover, the calculated SpO2 values from the proposed technique provide an average error of approximately 1.4%, whereas the conventional method yields a mean error approximately 4.2%. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heart detection and diagnosis based on ECG and EPCG relationships(2011-08-26); ; Yupapin, PPA new design of a system for preliminary detection of defective hearts is proposed which is composed of two subsystems, in which one is based on the relationship between the electrocardiogram (ECG) and phonocardiogram (PCG) signals. The relationship between both signals is determined as an impulse response (h(n)) of a system, where the decision is made based on the linear predictive coding coefficients of a heart's impulse response. The other subsystem uses a phase space approach, in which the mean squared error between the distance vectors of the phase space of the normal heart and abnormal heart is judged by the likelihood ratio test (Λ) value, on which the decision is made. The advantage of the proposed system is that a heart's diagnosis system based on the ECG and EPCG signals can lead to high performance heart diagnostics. © 2011 Phanphaisarn et al, publisher and licensee Dove Medical Press Ltd. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effects of hot air temperature on moisture reduction and drying time of turmeric in a closed-system herb dryer: kinetics and models(2023-11-01); Chantrawongphisal, BorisutThe primary objective of this research was to devise a model focused on the drying kinetics of turmeric, utilizing a closed-system herb dryer to facilitate energy conservation. Drying turmeric within this closed-system herb dryer involves a heat source—specifically, an electric coil heater powered at 3500 W and a humidity controller. The drying condition includes an air volume of 0.039 kg/s, the temperature at 40, 50, and 60 °C with initial moisture of the turmeric at 667.53 %db. The result of drying turmeric was analyzed using a thin-layer drying model for 8 models: Newton, Page, Logistic, Henderson and Pabis, Logarithmic, Two-Term, Approximation of Diffusion, Midill et al. The result shows that Midill et al. equation was the best model for predicting the drying behavior of turmeric. Therefore, this insinuates that the Midill model is superior to its contemporaneous counterparts in terms of accuracy. It offered the highest coefficient of determination R <sup>2</sup> (0.9998, 0.9996, 0.9999), the most root mean square error (RMSE) (3.39×10<sup>−9</sup>, 2.37×10<sup>−5</sup>, 3.10×10<sup>−5</sup>), the last chi-square χ <sup>2</sup> (3.39×10<sup>−9</sup>, 2.85×10<sup>−5</sup>, 3.99×10<sup>−5</sup>), and a temperature of 40, 50, and 60 °C, respectively. The study revealed that implementing a closed-system herb dryer could potentially manufacture high-value commodities while preserving their fundamental attributes. The closed-system herb dryer has been ingeniously designed as a proficient approach to diminish the drying time and improve the end product’s quality. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A Novel Chirp Demodulation Scheme Based on SAGC for Amateur Radio Data Transmission(2021-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Distance Detection Technique Using Enhancing Inverse Perspective Mapping(2018-09-11); This paper presents a distance determination technique using an image from the single forward camera. Since too dark or too bright of the image and non-linear relation between height of the object and distance from the camera have effect on the performance of the detection process. Therefore, automatic brightness adjustment and inverse perspective mapping (IMP) is applied in the proposed scheme. In addition, region of interest (ROI) determination is used to decrease the processing time. The experimental results confirm that the proposed technique can detect distance of the object in front of the car where the error is 7.96%.