Vuttichai Chatpattananan | King Mongkut's Institute of Technology Ladkrabang (KMITL) (original) (raw)

Papers by Vuttichai Chatpattananan

Research paper thumbnail of Model with a Generalized Ordering Policy

I am submitting herewith a dissertation written by Vuttichai Chatpattananan

Research paper thumbnail of Analysis and Design on Varying the Offsets in Superimposed Mechanically Stabilized Earth Walls

International Journal of GEOMATE

Superimposed MSE walls or multi-tier MSE walls are frequently used due to their eye-pleasing, eco... more Superimposed MSE walls or multi-tier MSE walls are frequently used due to their eye-pleasing, economical, and safety requirements compared with single-tall MSE walls. Designing an MSE wall requires checking the failure modes in its external stability, internal stability, and global stability. Calculating the external stability and global stability for superimposed walls is well explained. Internal stability, however, is more complicated in calculating the additional vertical stress from the upper wall as an equivalent surcharge on the lower wall with its magnitude determined by the offset distance. By varying offset distances, the additional vertical stress can be categorized into three cases. Case 1 is the maximum additional vertical from the upper wall load when the offset distance is less than HLtan(45-φr/2). The additional vertical stress is zero in case 3 where the offset distance is greater than H L tan(90-φ r). In case 2, the additional vertical stress is a hyperbola function that can be calculated easily using the proposed equation σ i = [(H L-z 1)/(z 2-z 1)](γH U +q) in Eq. (7) with geometric and algebraic explanations used through a numerical example in designing a superimposed wall.

Research paper thumbnail of Partial Discharge Classification on High Voltage Equipment with K-Means

2006 IEEE 8th International Conference on Properties and applications of Dielectric Materials

ABSTRACT This document proposes a statistical classification model using k-means cluster analysis... more ABSTRACT 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 (phi)-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

Research paper thumbnail of Exploring Factors Affecting Consumer Behavioral Intentions toward Online Food Ordering in Thailand

Sustainability

Due to the COVID-19 epidemic, ordering food online has become very popular. This study used a str... more Due to the COVID-19 epidemic, ordering food online has become very popular. This study used a structural equation model to analyze the indicators that influence the decision to order food through a food-delivery platform. The theory of planned behavior and the technology acceptance model were both used, along with a new factor, the task–technology fit (TTF) model, to study platform suitability. Data were collected using a questionnaire given to a group of 1320 consumers. The results showed that attitudes toward on-line delivery most significantly affected the behavioral intentions of the consumers, followed by subjective norms. Among attitudes, perceived ease of use was the most significant, followed by perceived usefulness and trust. The study’s results revealed that TTF had the most significant impact on perceived ease of use, followed by perceived usefulness. This means that, if a food-ordering platform is deemed appropriate, consumers will continue to use it, and business sustai...

Research paper thumbnail of Designing a Trapezoidal Modular Block Wall with Nonlinear Optimization

International Journal of GEOMATE, 2022

Research paper thumbnail of An Asymptotic Regression Predictive Model for Sphere Gap Voltage with Gap Diameter and Gap Spacing

2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena, 2006

This document develops two asymptotic regression models to estimate the value of sphere gap break... more 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 = b1+ b2eb 3Spacing + b4Diameter 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 r2 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.

Research paper thumbnail of PCA-LDA for Partial Discharge Classification on High Voltage Equipment

2006 IEEE 8th International Conference on Properties and applications of Dielectric Materials, 2006

ABSTRACT This document proposes a statistical classification model using principal component anal... more ABSTRACT This document proposes a statistical classification model using principal component analysis (PCA) for a data reduction approach combined with linear discriminant analysis (LDA) for a classification purpose, so called, PCA-LDA to classify 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 original independent variables in this classification model are skewness, kurtosis, asymmetry, and cross correlation following the phi - 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. With PCA, the original 10 independent variables can be reduced to 3 independent variables and using PCA can retains the accuracy of this classification model to 97.5 percent

Research paper thumbnail of A Classification of Partial Discharge on High Voltage Equipment with Multinomial Logistic Regression

2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena, 2006

ABSTRACT This document proposes a statistical approach in multinomial logistic regression to clas... more ABSTRACT This document proposes a statistical approach in multinomial logistic regression to classify 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 multinomial logistic regression model are skewness, kurtosis, asymmetry, and cross correlation following the Phi - 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 also applied stepwise model selection technique to reduce from 10 independent variables to 2 independent variables that not only reduces the complexity of the model estimated but also retains the accuracy of this predictive model to 96.2 percent.

Research paper thumbnail of Sustainability in Residential High-Rise Building Using Knowledge Management of Critical Success Technique

Sustainability is very important in business. The residential high-rise building all firms wanted... more Sustainability is very important in business. The residential high-rise building all firms wanted to successful and sustainability in business. There is need the construction to completed low time, low cost and high quality in construction work. Therefore, real estate developers must find various strategies to use in construction projects to achieve goals and success of the firm. The purpose of this study was to indicate the very importance of knowledge management can lead to sustainability in business. Analyze 14 critical success to sustainability in residential high-rise building projects, collected questions from literature review, and survey in deep interview senior managers of 15 projects real estate development firms listed on the stock market of Thailand. Budget building more than 1000 million baht per project. From conceptual frame work five foundations integrated to knowledge management of critical success (KMITL PROCESS) used made tool survey in deep interview the critical...

Research paper thumbnail of Applying hierarchical logistic models to compare urban and rural roadway modeling of severity of rear-end vehicular crashes

Accident Analysis & Prevention, 2020

A rear-end crash is a widely studied type of road accident. The road area at the crash scene is a... more A rear-end crash is a widely studied type of road accident. The road area at the crash scene is a factor that significantly affects the crash severity from rear-end collisions. These road areas may be classified as urban or rural and evince obvious differences such as speed limits, number of intersections, vehicle types, etc. However, no study comparing rear-end crashes occurring in urban and rural areas has yet been conducted. Therefore, the present investigation focused on the comparison of diverse factors affecting the likelihood of rear-end crash severities in the two types of roadways. Additionally, hierarchical logistic models grounded in a spatial basis concept were applied by determining varying parameter estimations with regard to road segments. Additionally, the study compared coefficients with multilevel correlation model and those without multilevel correlation. Four models were established as a result. The data used for the study pertained to rear-end crashes occurring on Thai highways between 2011 and 2015. The results of the data analysis revealed that the model parameters for both urban and rural areas are in the same direction with the larger number of significant parameter values present in the rural rear-end crash model. The significant variables in both the urban and rural road segment models are the seat belt use, and the time of the incident. To conclude, the present study is useful because it provides another perspective of rear-end crashes to encourage policy makers to apply decisions that favor rules that assure safety.

Research paper thumbnail of Analysis of Rear-End Crash on Thai Highway: Decision Tree Approach

Journal of Advanced Transportation, 2019

Objective. Among crash types on Thai highways, rear-end crashes have been found to cause the larg... more 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 Highw...

Research paper thumbnail of Measuring the motivation to ride bicycles for tourism through a comparison of tourist attractions

Transport Policy, 2016

In Thailand, supporting bicycle riding is regarded as an essential strategy. Many organizations a... more 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 ¼ 0.935), followed by exploration (β ¼0.900). For sea tourist attractions, contemplation was the factor having the highest CFA loadings equal 0.992 followed by stimulus seeking (β ¼0.937).

Research paper thumbnail of The Effect of Convexity of Lightning Impulse Voltage Waveforms on Accuracy of HV Measuring Systems

2006 International Conference on Power System Technology, 2006

ABSTRACT This paper presents the effect of convexity of lightning impulse voltage waveforms on ac... more ABSTRACT 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 Duhame'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.

Research paper thumbnail of A Linear Model for the Differences of Breakdown Voltages in IEC 60052 Tables

IEC 60052 table 2 and table 3 provides the values of breakdown voltage for sphere gap occurred fr... more IEC 60052 table 2 and table 3 provides the values of breakdown voltage for sphere gap occurred from different values of gap diameter and gap spacing. This document investigates the breakdown voltages from IEC 60052 table 2 and IEC 60052 table 3 under the same values of sphere gap diameter and gap spacing. The result shows that, provided the same condition of sphere gap diameter and gap spacing, the breakdown voltage value from table 3 (positive impulse) is higher than the breakdown voltage value from table 2 (negative impulse). Also, the relationship between the difference in breakdown voltage with diameter and spacing is simply a linear model in which a least square regression that minimizes sum of square errors can be used to find the relationship. With least square approach, a linear regression equation without an intercept term, or linear regression through the origin, is better accurate than the linear regression with an intercept term. The difference in breakdown voltage also ...

Research paper thumbnail of QUEST Tree Model for Partial Discharge Classification on High Voltage Equipment

This document proposes a statistical classification model using QUEST (Quick, Unbiased, and Effic... more This document proposes a statistical classification model using QUEST (Quick, Unbiased, and Efficient Statistical Tree) to classify 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 QUEST model are skewness, kurtosis, asymmetry, and cross correlation following the phi - 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 QUEST classification model can reduce the number of independent variables used to estimate from 10 independent variables to 3 independent variables with the classification accuracy of 100 percent

Research paper thumbnail of An implicit enumeration algorithm for mining high dimensional data

International Journal of Operational Research, 2005

Model selection is an important problem in mining information from large data bases. For example,... more Model selection is an important problem in mining information from large data bases. For example, in selecting a regression model, there may be J independent variables from which to choose, giving 2 J feasible possible combinations of models from which to choose. Information criteria such as

Research paper thumbnail of Linear Discriminant Analysis for Partial Discharge Classification on High Voltage Equipment

Conference on Electrical Insulation and Dielectric Phenomena, 2006

This document is addressing a problem in classifying partial discharge types using linear discrim... more 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

Research paper thumbnail of An ARIMA supply chain model with a generalized ordering policy

Journal of Modelling in Management, 2006

PurposeThis paper aims to present a method for production planning that reduces the bullwhip effe... more PurposeThis paper aims to present a method for production planning that reduces the bullwhip effect.Design/methodology/approachThe methods are derived using ARIMA models of the supply chain.FindingsThe resulting techniques produced an order policy that uses inventory or backlog to absorb the random variation in demand, but has immediate response to variation in the forecast level of demand.Research limitations/implicationsThe limitation of the research is that the optimality of the order policy is based on the assumption that the demand can be modeled using ARIMA models. When this is not the case the method can still be used as a heuristic approach to production smoothing.Practical implicationsThis paper offers a practical and easy to implement approach to production planning.Originality/valueThe paper introduces a generalized order policy and derives optimal production smoothing parameters for that order policy.

Research paper thumbnail of Designing Gabion Structures Under Multi-Criteria Objectives with Goal Programming

International Journal of GEOMATE, 2021

Gabion structure is a set of stacked prefabricated cages filled with rocks. These gabion cages ar... more 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.

Research paper thumbnail of A nonlinear optimization model on the reinforcement length of a modular block wall by varying surcharge and soil strength parameters

MATEC Web of Conferences, 2018

This study proposes a nonlinear optimization approach in designing a modular block wall which is ... more This study proposes a nonlinear optimization approach in designing a modular block wall which is a type of the mechanical stabilized earth wall. A nonlinear optimization model is proposed based on minimizing the reinforcement length where the constraints considered are the external stability and the internal stability. The optimum reinforcement length can be determined based on available soil strength parameters and the maximum surcharge. This study also includes the parametric study of the reinforced soil, retained soil, and foundation soil by varying the ranges of the wall height, surcharge, and soil strength parameters in density and friction angle to see the behaviours of the aforementioned external stability and internal stability. This can be beneficial in designing this modular block wall encountering a poor soil condition or a large amount surcharge.

Research paper thumbnail of Model with a Generalized Ordering Policy

I am submitting herewith a dissertation written by Vuttichai Chatpattananan

Research paper thumbnail of Analysis and Design on Varying the Offsets in Superimposed Mechanically Stabilized Earth Walls

International Journal of GEOMATE

Superimposed MSE walls or multi-tier MSE walls are frequently used due to their eye-pleasing, eco... more Superimposed MSE walls or multi-tier MSE walls are frequently used due to their eye-pleasing, economical, and safety requirements compared with single-tall MSE walls. Designing an MSE wall requires checking the failure modes in its external stability, internal stability, and global stability. Calculating the external stability and global stability for superimposed walls is well explained. Internal stability, however, is more complicated in calculating the additional vertical stress from the upper wall as an equivalent surcharge on the lower wall with its magnitude determined by the offset distance. By varying offset distances, the additional vertical stress can be categorized into three cases. Case 1 is the maximum additional vertical from the upper wall load when the offset distance is less than HLtan(45-φr/2). The additional vertical stress is zero in case 3 where the offset distance is greater than H L tan(90-φ r). In case 2, the additional vertical stress is a hyperbola function that can be calculated easily using the proposed equation σ i = [(H L-z 1)/(z 2-z 1)](γH U +q) in Eq. (7) with geometric and algebraic explanations used through a numerical example in designing a superimposed wall.

Research paper thumbnail of Partial Discharge Classification on High Voltage Equipment with K-Means

2006 IEEE 8th International Conference on Properties and applications of Dielectric Materials

ABSTRACT This document proposes a statistical classification model using k-means cluster analysis... more ABSTRACT 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 (phi)-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

Research paper thumbnail of Exploring Factors Affecting Consumer Behavioral Intentions toward Online Food Ordering in Thailand

Sustainability

Due to the COVID-19 epidemic, ordering food online has become very popular. This study used a str... more Due to the COVID-19 epidemic, ordering food online has become very popular. This study used a structural equation model to analyze the indicators that influence the decision to order food through a food-delivery platform. The theory of planned behavior and the technology acceptance model were both used, along with a new factor, the task–technology fit (TTF) model, to study platform suitability. Data were collected using a questionnaire given to a group of 1320 consumers. The results showed that attitudes toward on-line delivery most significantly affected the behavioral intentions of the consumers, followed by subjective norms. Among attitudes, perceived ease of use was the most significant, followed by perceived usefulness and trust. The study’s results revealed that TTF had the most significant impact on perceived ease of use, followed by perceived usefulness. This means that, if a food-ordering platform is deemed appropriate, consumers will continue to use it, and business sustai...

Research paper thumbnail of Designing a Trapezoidal Modular Block Wall with Nonlinear Optimization

International Journal of GEOMATE, 2022

Research paper thumbnail of An Asymptotic Regression Predictive Model for Sphere Gap Voltage with Gap Diameter and Gap Spacing

2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena, 2006

This document develops two asymptotic regression models to estimate the value of sphere gap break... more 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 = b1+ b2eb 3Spacing + b4Diameter 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 r2 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.

Research paper thumbnail of PCA-LDA for Partial Discharge Classification on High Voltage Equipment

2006 IEEE 8th International Conference on Properties and applications of Dielectric Materials, 2006

ABSTRACT This document proposes a statistical classification model using principal component anal... more ABSTRACT This document proposes a statistical classification model using principal component analysis (PCA) for a data reduction approach combined with linear discriminant analysis (LDA) for a classification purpose, so called, PCA-LDA to classify 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 original independent variables in this classification model are skewness, kurtosis, asymmetry, and cross correlation following the phi - 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. With PCA, the original 10 independent variables can be reduced to 3 independent variables and using PCA can retains the accuracy of this classification model to 97.5 percent

Research paper thumbnail of A Classification of Partial Discharge on High Voltage Equipment with Multinomial Logistic Regression

2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena, 2006

ABSTRACT This document proposes a statistical approach in multinomial logistic regression to clas... more ABSTRACT This document proposes a statistical approach in multinomial logistic regression to classify 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 multinomial logistic regression model are skewness, kurtosis, asymmetry, and cross correlation following the Phi - 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 also applied stepwise model selection technique to reduce from 10 independent variables to 2 independent variables that not only reduces the complexity of the model estimated but also retains the accuracy of this predictive model to 96.2 percent.

Research paper thumbnail of Sustainability in Residential High-Rise Building Using Knowledge Management of Critical Success Technique

Sustainability is very important in business. The residential high-rise building all firms wanted... more Sustainability is very important in business. The residential high-rise building all firms wanted to successful and sustainability in business. There is need the construction to completed low time, low cost and high quality in construction work. Therefore, real estate developers must find various strategies to use in construction projects to achieve goals and success of the firm. The purpose of this study was to indicate the very importance of knowledge management can lead to sustainability in business. Analyze 14 critical success to sustainability in residential high-rise building projects, collected questions from literature review, and survey in deep interview senior managers of 15 projects real estate development firms listed on the stock market of Thailand. Budget building more than 1000 million baht per project. From conceptual frame work five foundations integrated to knowledge management of critical success (KMITL PROCESS) used made tool survey in deep interview the critical...

Research paper thumbnail of Applying hierarchical logistic models to compare urban and rural roadway modeling of severity of rear-end vehicular crashes

Accident Analysis & Prevention, 2020

A rear-end crash is a widely studied type of road accident. The road area at the crash scene is a... more A rear-end crash is a widely studied type of road accident. The road area at the crash scene is a factor that significantly affects the crash severity from rear-end collisions. These road areas may be classified as urban or rural and evince obvious differences such as speed limits, number of intersections, vehicle types, etc. However, no study comparing rear-end crashes occurring in urban and rural areas has yet been conducted. Therefore, the present investigation focused on the comparison of diverse factors affecting the likelihood of rear-end crash severities in the two types of roadways. Additionally, hierarchical logistic models grounded in a spatial basis concept were applied by determining varying parameter estimations with regard to road segments. Additionally, the study compared coefficients with multilevel correlation model and those without multilevel correlation. Four models were established as a result. The data used for the study pertained to rear-end crashes occurring on Thai highways between 2011 and 2015. The results of the data analysis revealed that the model parameters for both urban and rural areas are in the same direction with the larger number of significant parameter values present in the rural rear-end crash model. The significant variables in both the urban and rural road segment models are the seat belt use, and the time of the incident. To conclude, the present study is useful because it provides another perspective of rear-end crashes to encourage policy makers to apply decisions that favor rules that assure safety.

Research paper thumbnail of Analysis of Rear-End Crash on Thai Highway: Decision Tree Approach

Journal of Advanced Transportation, 2019

Objective. Among crash types on Thai highways, rear-end crashes have been found to cause the larg... more 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 Highw...

Research paper thumbnail of Measuring the motivation to ride bicycles for tourism through a comparison of tourist attractions

Transport Policy, 2016

In Thailand, supporting bicycle riding is regarded as an essential strategy. Many organizations a... more 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 ¼ 0.935), followed by exploration (β ¼0.900). For sea tourist attractions, contemplation was the factor having the highest CFA loadings equal 0.992 followed by stimulus seeking (β ¼0.937).

Research paper thumbnail of The Effect of Convexity of Lightning Impulse Voltage Waveforms on Accuracy of HV Measuring Systems

2006 International Conference on Power System Technology, 2006

ABSTRACT This paper presents the effect of convexity of lightning impulse voltage waveforms on ac... more ABSTRACT 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 Duhame'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.

Research paper thumbnail of A Linear Model for the Differences of Breakdown Voltages in IEC 60052 Tables

IEC 60052 table 2 and table 3 provides the values of breakdown voltage for sphere gap occurred fr... more IEC 60052 table 2 and table 3 provides the values of breakdown voltage for sphere gap occurred from different values of gap diameter and gap spacing. This document investigates the breakdown voltages from IEC 60052 table 2 and IEC 60052 table 3 under the same values of sphere gap diameter and gap spacing. The result shows that, provided the same condition of sphere gap diameter and gap spacing, the breakdown voltage value from table 3 (positive impulse) is higher than the breakdown voltage value from table 2 (negative impulse). Also, the relationship between the difference in breakdown voltage with diameter and spacing is simply a linear model in which a least square regression that minimizes sum of square errors can be used to find the relationship. With least square approach, a linear regression equation without an intercept term, or linear regression through the origin, is better accurate than the linear regression with an intercept term. The difference in breakdown voltage also ...

Research paper thumbnail of QUEST Tree Model for Partial Discharge Classification on High Voltage Equipment

This document proposes a statistical classification model using QUEST (Quick, Unbiased, and Effic... more This document proposes a statistical classification model using QUEST (Quick, Unbiased, and Efficient Statistical Tree) to classify 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 QUEST model are skewness, kurtosis, asymmetry, and cross correlation following the phi - 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 QUEST classification model can reduce the number of independent variables used to estimate from 10 independent variables to 3 independent variables with the classification accuracy of 100 percent

Research paper thumbnail of An implicit enumeration algorithm for mining high dimensional data

International Journal of Operational Research, 2005

Model selection is an important problem in mining information from large data bases. For example,... more Model selection is an important problem in mining information from large data bases. For example, in selecting a regression model, there may be J independent variables from which to choose, giving 2 J feasible possible combinations of models from which to choose. Information criteria such as

Research paper thumbnail of Linear Discriminant Analysis for Partial Discharge Classification on High Voltage Equipment

Conference on Electrical Insulation and Dielectric Phenomena, 2006

This document is addressing a problem in classifying partial discharge types using linear discrim... more 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

Research paper thumbnail of An ARIMA supply chain model with a generalized ordering policy

Journal of Modelling in Management, 2006

PurposeThis paper aims to present a method for production planning that reduces the bullwhip effe... more PurposeThis paper aims to present a method for production planning that reduces the bullwhip effect.Design/methodology/approachThe methods are derived using ARIMA models of the supply chain.FindingsThe resulting techniques produced an order policy that uses inventory or backlog to absorb the random variation in demand, but has immediate response to variation in the forecast level of demand.Research limitations/implicationsThe limitation of the research is that the optimality of the order policy is based on the assumption that the demand can be modeled using ARIMA models. When this is not the case the method can still be used as a heuristic approach to production smoothing.Practical implicationsThis paper offers a practical and easy to implement approach to production planning.Originality/valueThe paper introduces a generalized order policy and derives optimal production smoothing parameters for that order policy.

Research paper thumbnail of Designing Gabion Structures Under Multi-Criteria Objectives with Goal Programming

International Journal of GEOMATE, 2021

Gabion structure is a set of stacked prefabricated cages filled with rocks. These gabion cages ar... more 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.

Research paper thumbnail of A nonlinear optimization model on the reinforcement length of a modular block wall by varying surcharge and soil strength parameters

MATEC Web of Conferences, 2018

This study proposes a nonlinear optimization approach in designing a modular block wall which is ... more This study proposes a nonlinear optimization approach in designing a modular block wall which is a type of the mechanical stabilized earth wall. A nonlinear optimization model is proposed based on minimizing the reinforcement length where the constraints considered are the external stability and the internal stability. The optimum reinforcement length can be determined based on available soil strength parameters and the maximum surcharge. This study also includes the parametric study of the reinforced soil, retained soil, and foundation soil by varying the ranges of the wall height, surcharge, and soil strength parameters in density and friction angle to see the behaviours of the aforementioned external stability and internal stability. This can be beneficial in designing this modular block wall encountering a poor soil condition or a large amount surcharge.