Now showing 1 - 10 of 22
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    Partial discharge classification on high voltage equipment with K-means
    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.
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    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)
    Ahmed, Mukhtar
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    In response to increasing demand for environmental sustainability, construction firms are progressively adopting green-oriented management approaches to enhance long-term project success. This study examines the relationship between Green Human Resource Management (GHRM), Green Human Capital (GHC) and Sustainable Project Success (SPS) within the construction sector, with Green Work Climate (GWC) as moderator and Green Construction Practices (GCP) as mediator. Drawing upon the Resource-Based View (RBV), Natural Resource-Based View (NRBV), and Ability-Motivation-Opportunity (AMO) theory, the study explains how green human competencies and HR systems are associated with project sustainability. Data were collected from 436 construction professionals in Bangkok, Thailand, through online questionnaires, and analyzed using SmartPLS 4 and Structural Equation Modeling (SEM) analysis. The findings indicate that GHRM is positively associated with SPS, while GHC demonstrates an indirect relationship with SPS through GCP. The moderating effect of GHC was not supported. These results contribute to sustainable construction management literature by clarifying the mechanisms through which green human resources are converted to sustainability, offering practical implications for construction firms seeking to institutionalize sustainability through structured HR policies and operational practices.
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    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.
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    Measuring the motivation to ride bicycles for tourism through a comparison of tourist attractions
    (2016-11-01)
    Watthanaklang, Duangdao
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    Ratanavaraha, Vatanavongs
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    Jomnonkwao, Sajjakaj
    In 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).
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    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.
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    Analysis of Rear-End Crash on Thai Highway: Decision Tree Approach
    (2019-01-01)
    Champahom, Thanapong
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    Jomnonkwao, Sajjakaj
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    Karoonsoontawong, Ampol
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    Ratanavaraha, Vatanavongs
    Objective. Among crash types on Thai highways, rear-end crashes have been found to cause the largest number of fatalities. This study aims to find ways to decrease rear-end crashes and fatal rear-end crashes. Methods. Classification and regression tree (CART) was used to analyze the complicated relationship of variables of big data. The analysis was conducted by creating two models: (1) a model which indicates the causes of rear-end crashes by applying Quasi-Induced Exposure to at-fault driver characteristics; (2) a determined model which studies fatal crashes. Results. Predictor variables in the model of at-fault and not-at-fault drivers found that driver age is most significant, followed by number of lanes and median opening area. For the mode of fatality, the use of safety equipment was found to be of most importance. Conclusion. The model results can be used to develop guidelines for public awareness programs for motorists and to propose policy changes to the Department of Highway in order to reduce the severity of rear-end crashes. Moreover, this paper discusses the variables that may result in both the perspective of rear-end crash number and the fatality rate of rear-end crashes as strategies in future research.
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    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.
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    Analysis of Key Factors of Cost Overrun in Construction Projects Based on Structural Equation Modeling
    (2025-03-01)
    Dong, Sizi
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    Ahmed, Mukhtar
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    Cost overruns are prevalent in global construction industries, propelled by the swift expansion of the construction sector. To tackle this difficulty, it is essential to comprehend the primary elements leading to these overruns. This research examines the correlation between systematic elements affecting construction costs via a literature review, expert interviews, exploratory factor analysis (EFA), and structural equation modeling (SEM). A theoretical framework analyzes contract management, resource distribution, and external environmental factors affecting cost overruns. Twenty-four criteria were selected via literature review and expert consultation, and data from 212 questionnaires were analyzed. The results identify 22 critical elements classified into project management, resources, supply chain, and external and environmental influences. Project management and resources, together with supply chain, exerted the most significant influence. SEM study indicates that management inadequacies intensify resource problems, whereas proficient internal management alleviates external difficulties. This research offers practical recommendations for mitigating budget excesses and enhancing project cost-effectiveness.
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    Designing gabion structures under multi-criteria objectives with goal programming
    (2021-06-01) ; ;
    Ratanavaraha, Vatanavongs
    Gabion 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.
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    The Seismic Resistance Analysis of Frame Structures and Wall Structures Using Ferrocement and Expanded Metal
    (2023-04-01)
    Chonratana, Yossakorn
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    This article presents a study of the use of ferrocement and expanded metal in the columns, beams, and walls of a reinforced concrete building structure to increase its seismic resistance. This study focused on a concrete building with three stories, located in Thailand. In the design of the reinforcement structure, a calculation and analysis of seismic resistance were conducted in a comparison of the original concrete building structure with the reinforced concrete building structure using the nonlinear static force method (pushover analysis method). The results showed that the seismic resistance of the reinforced concrete building structure was higher than the design value (DPT), with different seismic resistance values for the reinforced frames, columns, and walls of approximately 14%, 81%, and 19%. In particular, it had increased stiffness values for the frames, columns, and walls and increased ductility values for the walls. Moreover, the seismic resistance values originating from the reinforcement were significantly higher than those of the concrete building structure. Therefore, reinforcement should be applied to all concrete building structures with the implementation of the damage index, ensuring that it is reduced to the allowable level.