Chutchavong, Vanvisa

Preferred name

Alternative Name

Chutchavong, V.

Main Affiliation

School of Engineering

vanvisa.ch@kmitl.ac.th

Now showing 1 - 10 of 48

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Study on Damage to Flexible Pavement Road in Thailand: Identification Types of Crack on Roads Using Image Processing Takes
(2025-01-01)
Chutchavong, Vanvisa
;
Doungpan, Satawat
;
Kasettakarn, Witchapon
;
Thiabkhuang, Surapit
;
Phungtua-Eng, Thanapol
The detection and identification of flexible pavement road cracks pose a significant challenge for civil engineers when they start work at the beginning level, as it requires extensive work experience of engineers in classifying types of cracks for planning road maintenance. Inaccurate analysis and identification of cracks can negatively affect the quality of maintenance work and threaten the safety of road users in the future. This paper presents a case study of 60 asphalt roads managed by the Provincial Administrative Organization (PAO) in central of Thailand (case of two provinces, Uthai Thani and Nakhon Sawan), focusing on identification type road cracks. The study aims to address issues related to data preparation and classification across various domains Our data are fed model, which is photography to medium-resolution images of flexible pavement road cracks so that guidelines for engineers' inspection and identification of road cracks. We propose the development of a U-Net model specifically designed for image processing tasks. The results indicate that the U-Net model is effective in converting road cracks images into segmentation masks, and this effectiveness is evaluated using four well-defined key performance indicators.
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Sine-Squared pulse approximation using generalized bessel polynomials
(2019-05-29)
Anuwongpinit, Thanavit
;
Chutchavong, Vanvisa
;
Janchitrapongvej, Kanok
;
Benjangkaprasert, Chawalit
This paper presents the approximation of sine-squared pulse based on the generalized Bessel polynomials. For designing a circuit to synthesize a sine-squared pulse test signal. The generalized Bessel polynomials have more parameter than classical Bessel polynomials that have alpha and beta parameters for adjusting the dominator of the transfer function to approximate the sine-squared pulse that closes to the ideal pulse. The simulation results show that the generalized Bessel polynomial can adjust the approximation response close to the ideal response. The orders of the transfer function are decreased that confirm a better performance than the previous works.
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Equalization of the distorted chrominance signal using IIR digital filter with the bernstein filter
(2005-01-01)
Chutchavong, V.
;
Janchitrapongvej, K.
;
Pirajnanchai, V.
In this paper, we present the use of the Bernstein Polynomials to obtain an IIR digital filter transfer function, which can be applied to video equalizer for compensating the amplitude of chrominance signal in color television. In addition, experimental results are carried out by using the modulated 20T sine squared signal on the color sub carrier 4.43 MHz. It is shown here that the proposed equalizer can either enhance or compress the chrominance signal in color television transmission.
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Approximation of the maximally flat filter by using Bézier curve with an exponential function
(2020-02-24)
Purahong, B.
;
Kanjanasurat, I.
;
Sithiyopasakul, P.
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Chutchavong, V.
;
Pintavirooj, C.
This paper presents a design of filter by using Bézier curve with an exponential function. This paper used the advantage of The Bézier curve which had ability for approximation and an exponential function which had the adaptable parameters of the polynomial. It can adjust the characteristic of frequency response for the best performance. The simulation results of various setting show the frequency response, step response. The comparison of response between the Bernstein filter and Butterworth filter in order two show that the rise time of Bernstein filter better than Butterworth filter and Bézier curve filter has not overshoot. Furthermore, the stability Nyquist criterion has been used to guarantee the stability of the transfer function.
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Bernstein polynomial and rational Bézier curve for blood pressure simulation
(2017-02-08)
Kanjanasurat, I.
;
Chutchavong, V.
;
Pirajnanchai, V.
;
Janchitrapongvej, K.
This paper presents blood pressure waveform simulation using the Bernstein polynomial model, Bézier-Bernstein model, and Rational Bézier-Bernstein model. All mathematical models can generate the blood pressure waveform which is similar to the normal blood pressure waveform. Moreover, all mathematical models can simulate a normal blood pressure waveform as well. As the results, the Rational Bezier-Bernstein model is a simple form, low order, easy to implement in the microcontroller.
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An IIR digital video equalizer design with the bernstein polynomial and generalized bilinear transformation for gain chrominance distortion
(2008-12-01)
Chutchavong, V.
;
Sangaroon, O.
;
Pirajnanchai, V.
;
Janchitrapongvej, K.
Video equalizer design for compensated the distortion of the chrominance amplitude in color television transmission system is presented. The approximation is based on the Bernstein Polynomials and generalized bilinear transformation to obtain the transfer function. This approach has several parameters can be varied satisfying stability conditions. And the advantages of the Bernstein Polynomials when compared to the Butterworth, Chebyshev and Thomson Polynomials are three parameters available control the amount of phase and magnitude, linear phase, and flexible for variable of phase. Among all referred advantages so that these methodologies were applied in this paper. In addition, the pulse and bar test signal which has been used to measure linear waveform distortion in TV system is special the modulated 20T sine squared pulse with color sub-carrier 4.43 MHz for PAL system. As a result, the proposed digital video equalizer can be enhance and compress the gain chrominance distortion without degraded it phase characteristic.
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Implementation of ECG portable device for real-time signal monitoring
(2017-11-24)
Purahong, B.
;
Thongkrairat, S.
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Anuwongpinit, T.
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Chutchavong, V.
;
Aoyama, H.
In this paper presents a system for heart rate signal analysis in ECG (Electrocardiography) format using STM32f7 board. Electrode is used for recording the signal with stick on body in lead 2 orientations. Signal processing method are used upper average, slope and interval checking algorithm to process ECG signal in real-time. In experiment, to acquire a frequency of heart beat and display ECG signal and heart rate on STM32f7 board compare with wearable device that result have error rate less than 1%. This system is portable to use and sufficient battery for recording signal to analyze and monitor throughout the day.
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Measurement and examination of the relation between ionospheric scintillation expression methods in equatorial region
(2002-01-01)
Chutchavong, V.
;
Sangaroon, O.
;
Janchitrapongvej, K.
;
Nakasuwan, J.
;
Moriya, Y.
This paper examines the method for converting among scintillation expression methods, peak to peak values method and standard deviation values method, by using local measurement of meteorological parameters. Part I focus on tropospheric scintillation related to 12.260 GHz measurements at an elevation angle of 59.9°. Part II focus on ionospheric scintillation describes 3.916 GHz, observations made on three years periods at KMITL, Bangkok, Thailand. The principle techniques finding the good correlation coefficient ranging from 0.900 to 0.999. As a result extremely the relationship between two methods is given by σ<inf>x</inf>=α(p-p) + β, where α is 0.14.
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New crossover network based on q-bernstein polynomial
(2016-01-01)
Sookcharoenphol, Dolchai
;
Nomura, Hideyuki
;
Kanamori, Chisato
;
Aoyama, Hisayuki
;
Janjitrapongvej, Kanok
This paper presents a new audio crossover network based on q-Bernstein polynomial which can be adjustable attenuation in stop-band by varying parameters of the transfer function. The crossover network gives an in-phase response and a flat summed of magnitude response of each filter through audio frequency band. The simulation results shown that the crossover network given high attenuation in stop-band which better than conventional crossover network at second-order and fourth-order. Moreover, the crossover network structure can be reduced complexity by based on subtractive circuits. Therefore, the proposed crossover network provided a high quality crossover network and can useful for professional reproduction sound systems.
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Assessment of Electromagnetic Field Exposure from Multiple Sources Simultaneously in the High-Frequency Range Based on Safety Standards
(2025-01-01)
Chutchavong, Vanvisa
;
Aroonmitr, Pongsathorn
This study presents a method for evaluating electromagnetic field (EMF) exposure from multiple sources operating simultaneously across a wide range of frequencies, based on the guidelines defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) in its 2020 publication. The proposed approach adopts the normalized exposure ratio, which combines the exposure values from all relevant sources and frequency bands. A key issue addressed in this study is the lack of standardized measurement methods for absorbed power density (S<inf>ab</inf>) in high-frequency bands above 10 GHz, despite the existence of defined exposure limits. A comparison reveals that the difference between the limits for S<inf>ab</inf> and incident power density (S<inf>inc</inf>) for the general public is relatively small when compared to the gap between the general public and occupational exposure limits. Therefore, the use of S<inf>inc</inf> is proposed as a temporary surrogate for S<inf>ab</inf> in frequency ranges where direct measurement is not yet feasible. This approach enables comprehensive exposure assessment from multiple sources under both near-field and far-field conditions. It also serves as a practical alternative while S<inf>ab</inf> measurement techniques for high-frequency applications such as 5G, WiGig, and next-generation wireless technologies are still under development.

Chutchavong, Vanvisa

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