Chatpattananan, Vuttichai
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Chatpattananan, Vuttichai
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Chatpattananan, V.
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vuttichai.ch@kmitl.ac.th
22 results
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Item type:Publication, Partial discharge classification on high voltage equipment with K-means(2006-01-01); ; This document proposes a statistical classification model using k-means cluster analysis to classify partial discharge (PD) patterns into four categories listed as corona at high voltage side in air, corona at low voltage side in air, surface in air, and internal discharge. The independent variables in this k-means cluster analysis model are skewness, kurtosis, asymmetry, and cross correlation following the φ - q - n PD patterns obtained from the fingerprint analysis which is a digital signal processing technique for PD measurement. The experiments were set to simulate all four PD patterns to obtain statistical parameters into 10 independent variables from the fingerprint analysis. This document recommends using 8 final clusters instead of using 4 final clusters to achieve the accuracy of using this k-means cluster approach to 100 percent. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Empowering Sustainable Project Success in Construction: The Strategic Role of Green HRM and Green Human Capital Through Green Construction Practices and Green Work Climate(2026-04-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The effect of convexity of lightning impulse voltage waveforms on accuracy of HV measuring systems(2006-01-01); ; ; Phoomvuthisarn, S.This paper presents the effect of convexity of lightning impulse voltage waveforms on accuracy of HV measuring systems. The effects of different three convexities on wave front are analyzed by simulation tests with some standard waveforms. The simulation tests have two aspects. First one is consideration in frequency domain by using FFT with standard waveforms and transfer function of measuring system and second one is consideration in time domain by using time convolution method or Duhamel's integration method for computing waveform outputs standard testing waveforms and unit step responses of the sample measuring systems. The standard waveforms under investigations are full lightning impulse voltage waveforms, tail-chopped of lightning impulse voltage waveforms, front-chopped of lightning impulse voltage waveforms according to IEC standards 60060-2. This paper considers two samples of different types of the measuring systems. The results show that the convexity has effect on accuracy of measuring systems. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Measuring the motivation to ride bicycles for tourism through a comparison of tourist attractions(2016-11-01); Jomnonkwao, SajjakajIn Thailand, supporting bicycle riding is regarded as an essential strategy. Many organizations are developing campaigns and activities to promote bicycle riding. However, most Thai people do not enjoy riding bicycles. Thus, this study aims to understand the motivational components and compare the different motivations for bicycle riding in various areas using confirmatory factor analysis (CFA). Six factors were considered: self-development, contemplation, exploration, physical challenge, stimulus seeking, and social interaction. The samples used in this study were 798 Thai tourists. The results of the second-order CFA indicate that six factors indicated motivation to ride bicycles at these tourist attractions at a statistical significance of 0.01. Moreover, the invariance analysis of the model parameters for the two areas through chi-square difference testing shows that factor loadings, intercepts, and the structural path have different values for tourist attractions in the mountains and those by the sea at a statistical significance of 0.01. Thus, models for tourist attractions in the mountain and those by the sea should be developed separately to determine suitable policies for these areas. Consequently, the government sectors and other involved organizations should use these indicators to develop more precise and suitable policies to promote bicycle riding for targeted groups. The CFA loadings obtained from this study can be used for ranking the priority of improving motivation for riding bicycles. Regarding mountain tourist attractions, contemplation was the factor having maximum CFA loading (β=0.935), followed by exploration (β=0.900). For sea tourist attractions, contemplation was the factor having the highest CFA loadings equal 0.992 followed by stimulus seeking (β=0.937). - Some of the metrics are blocked by yourconsent settings
Item type:Publication, An asymptotic regression predictive model for sphere gap voltage with gap diameter - And gap spacing(2006-12-01)This document develops two asymptotic regression models to estimate the value of sphere gap breakdown voltage from any value of gap diameter and gap spacing under IEC 60052 table 2 and table 3 to facilitate those two IEC tables that provide limited values consisting of 12 sizes in sphere diameter ranging from 20 mm to 2000 mm and sphere gap spacing range from 0.5 mm to 1500 mm. In those two IEC tables, the relationship of sphere gap voltages from sphere gap diameter and gap spacing is nonlinear in which asymptotic regression models are proposed is in the form Voltage = b<inf>1</inf> + b<inf>2</inf>e <sup>b3Spacing</sup> + b<inf>4</inf>Diameter that follows the law of diminishing returns that imitates the relationship between sphere gap voltages versus sphere gap diameter and gap spacing. By using this asymptotic regression, this document provides expressions of standard sphere gap voltages as functions of the sphere gap diameter and gap spacing. The expressions are in high accuracy measured by r<sup>2</sup> values. These proposed asymptotic regression equations can be used to estimate sphere gap voltage breakdown from any values of sphere gap diameter and gap spacing that are not specified by IEC 60052 tables. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Linear discriminant analysis for partial discharge classification on high voltage equipment(2006-12-01)This document is addressing a problem in classifying partial discharge types using linear discriminant analysis. Four PD types generated in the lab are corona at high voltage side in air, corona at low voltage side in air, surface in air, and internal discharge. The independent variables used in this linear discriminant analysis model mainly are from skewness, kurtosis, asymmetry, and cross correlation following the φ - q - n PD patterns obtained from the fingerprint analysis which is a digital signal processing technique for PD measurement. This document also applied stepwise model selection technique to reduce from 10 independent variables to 8 independent variables that not only reduces the complexity of the model estimated but also retains the accuracy of this predictive model to 98.7 percent. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Designing gabion structures under multi-criteria objectives with goal programming(2021-06-01); ; Ratanavaraha, VatanavongsGabion structure is a set of stacked prefabricated cages filled with rocks. These gabion cages are made of steel wire, polypropylene, polyethylene, or nylon. Constructing these gabion cages usually follows supplier guidelines or governmental agency design standards. Designing this gabion structure, at a minimum, must satisfy many design criteria in passing external stability in sliding, overturning, and bearing capacity of the foundation. Good gabion design requires a balance of the toe bearing stress and heel bearing stress. With this requirement for the design of gabion structures to meet multi-criteria objectives, goal programming, which is a multi-criteria optimization technique, is used in this study. A 3-meter gabion example is used as a based design. Then, mixed integer nonlinear programming is introduced to rearrange a set of varying sized gabion cages to minimize the gabion weight and passing external stability criteria. Two goal programming models are introduced to meet the two design criteria in minimizing gabion weight and balancing the vertical stresses. The two goal programming models give the same optimum solution with the minimum weight of 48 kN/m and eccentricity of 0.002 meter. In contrast, the original example gives the weight of 61.92 kN/m and eccentricity of 0.086 meter. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Seismic Resistance Analysis of Frame Structures and Wall Structures Using Ferrocement and Expanded Metal(2023-04-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, How Key Success Factors Improve Delay Mitigation in Construction Projects: The Mediating Role of Project Readiness(2026-06-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, DESIGNING A TRAPEZOIDAL MODULAR BLOCK WALL WITH NONLINEAR OPTIMIZATION(2022-02-01); ; Ratanavaraha, VatanavongsA rectangular wall is better in terms of stability and ease of calculation than a trapezoidal wall. However, a trapezoidal wall is sometimes inevitable such as a retaining wall construction near rockface. FHWA provides simplified rules to design a trapezoidal wall. However, FHWA does not give an example to follow, and the rules need trial and error to implement. BS8006 gives an exact dimension of the block heights, but designing still needs to adjust the block widths. A 16-meters high modular block wall project near rock face in Thailand as an example to illustrate a calculation detail in external stability checking follow FHWA simplified rules and BS8006. The illustrations are trapezoidal walls with two zones, three zones, and four zones. Nonlinear optimization models are also used to minimize the wall base length to facilitate the construction instead of jacking the near rock face to build a rectangular wall. Optimization models also help to relax FHWA simplified rules and BS8006 guidelines. Using an optimization model can decrease the base length from 0.7H to 0.6H for a rectangular wall or even 0.5H for a rectangular wall with competent foundation soil. Optimization models can also achieve a base length down to 0.48H with a decrease in the cross-sectional area down to 0.92 for a three zones trapezoidal wall. A simple three zones wall with exact dimensions is also proposed in the competent foundation soil conditions.