• Structural Engineering and Mechanics
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• v.66 no.4
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• pp.423-438
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• 2018

This pioneer study focuses on finite element modeling and numerical modeling of three types of Reinforced Concrete Haunched Beams (RCHBs). Firstly, twenty RCHBs, consisting of three types, and four prismatic beams which had been tested experimentally were modeled via a nonlinear finite element method (NFEM) based software named as, ATENA. The modeling results were compared with experimental results including load capacity, deflection, crack pattern and mode of failure. The comparison showed a good agreement between the results and thus the model used can be effectively used for further studies of RCHB with high accuracy. Afterwards, new mechanism modes and design code equations were proposed to improve the shear design equation of ACI-318 and to predict the critical effective depth. These equations are the first comprehensive formulas in the literature involving all types of RCHBs. The statistical analysis showed the superiority of the proposed equation to their predecessors where the correlation coefficient, $R^2$ was found to be 0.89 for the proposed equation. Moreover, the new equation was validated using parametric and reliability analyses. The parametric analysis of both experimental and predicted results shows that the inclination angle and the compressive strength were the most influential parameters on the shear strength. The reliability analysis indicates that the accuracy of the new formulation is significantly higher as compared to available design equations and its reliability index is within acceptable limits.

• Computers and Concrete
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• v.33 no.6
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• pp.725-738
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• 2024

This study presents a macro-modeling procedure for nonlinear finite element analysis of reinforced and prestressed concrete panels under blast loading. The analysis procedure treats cracked concrete as an orthotropic material based on a smeared rotating crack model within the context of total-load secant stiffness-based formulation. A direct time integration method compatible with the analysis formulation is adapted to solve the dynamic equation of motion. Considerations are made to account for strain rate effects. The analysis procedure is verified by modeling 14 blast tests from various sources reported in the literature including a blast simulation contest. The analysis results are compared against those obtained from experiments, simplified single-degree-of-freedom (SDOF) methods, and sophisticated hydrocodes. It is demonstrated that the smeared crack macro-modeling approach is a viable alternative analysis procedure that gives more information about the structural behavior than SDOF methods, but does not require detailed micro-modeling and extensive material characterization typically needed with hydrocodes.

• Journal of Korean Society of Transportation
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• v.29 no.3
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• pp.93-101
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• 2011

In 2008, Korea has observed total 215,822traffic accidents Although the number has decreased since then, the crash rate is still higher than those of other advanced countries. In particular, high rate of pedestrian accidents occurred on urban streets is recognized as a serious problem. The previous studies, however, are not entirely considerate of accident factors by accident type. Inspired by the fact, this study analyzes factors affecting traffic accident by accident type. Using the accident data collected on urban streets in Seodaemun-gu, this paper classifies the accidents into two groups (i.e., vehicle-vs-vehicle and vehicle-vs-person crashes), and analyzes relationships between severity and exogenous variables. For the analysis, Structural Equation Modeling (SEM) is employed to estimate relationships among exogenous factors of traffic accident by each type on urban streets. The resulting model reveals that roadway related factors are highly correlated with the severity of vehicle-vs-vehicle crashes whereas environment factors are with vehicle-vs-person crashes.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.1
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• pp.131-147
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• 2016

This study investigated the relationship between fashion behavior, impression management behavior, and career success. A conceptual model and hypotheses were established based on theoretical linkages between the constructs. Thereafter, empirical data were collected using a set of questionnaires. For this reason, the sample was taken from 720 office workers' who worked at 14's Korea Enterprise, 697 of which was used for an empirical analysis (sample: men over 30 years of age and more than three years continuous service). This study conducted an exploratory factor analysis and confirmatory factor analysis for the validity test. Cronbach's alpha test is used for the reliability test. Moreover, PLS structural equation modeling (SEM) was employed to test hypothesized relationships in the conceptual model (SPSS 20.0 window/Smart PLS 3.0). This study shows that the proposed model is reasonably fit to the actual data. The following results were obtained from the analyses. First, fashion behavior and impression management behavior is positively related to career success. The result shows that economics of the fashion behaviors sub-types were statistically more significant to influence career success. The self-focused of the impression management behavior sub-types were more than statistically significant to influence career success. This finding has great implications to understand self-management behavior and the career success of male office workers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.183-190
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• 2009

In order to improve continuous success and stabilization of high-speed rail in the future, Using Frequency of high-speed rail should be enhanced by improving satisfaction of high-speed rail passenger. High-speed rail is needed to hold the priority in competition means by comparing the traits of service of domestic air lines. This study utilizes structural equation modeling to develop model for estimating factors influencing to service through conducting survey questionnaire. It also uses reliability analysis, correlation analysis, factor analysis to examine the rationalization of items and to establish hypothesis of this research. The results show that KTX contains 'inner service' item that is considered to be ameliorated and that domestic airline present low performance of 'outer service' item. In other words, moving section which partly is under a limited condition is needed to be improved. In addition, access to airport and transfer to other transportations have to be improved as they show the lowest satisfaction.

• Structural Engineering and Mechanics
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• v.84 no.2
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• pp.207-224
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• 2022

The mechanical behavior of prestressed concrete haunched beams (PSHBs) was investigated in depth using a finite element modeling technique in this study. The efficiency of finite element modeling was investigated in the first stage by taking into account a previous study from the literature. The first stage's findings suggested that finite element modeling might be preferable for modeling PSHBs. In the second stage of the research, a comprehensive parametric study was carried out to determine the effect of each parameter on PSHB load capacity, including haunch angle, prestress level, compressive strength, tensile reinforcement ratio, and shear span to depth ratio. PSHBs and prestressed concrete rectangular beams (PSRBs) were also compared in terms of capacity. Stochastic analysis was used in the third stage to define the uncertainty in PSHB capacity by taking into account uncertainty in geometric and material parameters. Standard deviation, coefficient of variation, and the most appropriate probability density function (PDF) were proposed as a result of the analysis to define the randomness of capacity of PSHBs. In the study's final section, a new equation was proposed for using symbolic regression to predict the load capacity of PSHBs and PSRBs. The equation's statistical results show that it can be used to calculate the capacity of PSHBs and PSRBs.

• KIPS Transactions on Computer and Communication Systems
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• v.13 no.1
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• pp.1-9
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• 2024

In the development and mass production of polymers, there are many uncontrollable variables. Even small changes in chemical composition, structure, and processing conditions can lead to large variations in properties. Therefore, Traditional linear modeling techniques that assume a general environment often produce significant errors when applied to field data. In this study, we propose a new modeling method (GPR-SEM) that combines Structural Equation Modeling (SEM) and Gaussian Process Regression (GPR) to study the Friction-Coefficient and Flexural-Strength properties of Polyacetal resin, an engineering plastic, in order to meet the recent trend of using plastics in industrial drive components. And we also consider the possibility of using it for materials modeling with nonlinearity.

• Journal of Agricultural Extension & Community Development
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• v.25 no.1
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• pp.1-13
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• 2018

This study aims to identify factors affecting the acceptance intention of cultivating a new Italian ryegrass(IRG) variety using partial least square structural equation modeling(PLS-SEM) and find priority to maximize the acceptance intention of new IRG variety using importance-performance matrix analysis(IPMA). The data were collected on a seven-point Likert-type from 188 farm households located in Korea central region for two months. As a major result of PLS-SEM, expected effect significantly affected acceptance intention. The IPMA also showed expected effect should be considered as the most important factor to improve the acceptance intention. This study suggested the new technology distributors should scientifically prove and actively promote the effects such as increase in farm income, productivity improvement, labor saving and management efficiency caused by planting new IRG variety.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.111-121
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• 2016

This study provides an approach to perform the double mediation analysis in structural equation models using the R. For this purpose, the study reviews a variety of techniques for mediation analysis, selects the bootstrapping technique as the most suitable way for performing the double mediation analysis and develops an approach for the double mediation analysis in structural equating models with the bootstrapping using the plspm which is the R package for the performing PLS path analysis. This study will be useful for the studies including the double mediation analysis in structural equation modeling, which is not supported by most of SEM packages, also will provide the knowledge base for in-depth analysis through suggesting the new mediation analysis technique using R for the researchers.

• Korean Journal of Human Ecology
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• v.24 no.6
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• pp.783-793
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• 2015

The purpose of this study was to investigate the effect of Parenting Attitude, Self-esteem, and Peer Attachment on Emotion Problem. The study is based on data from first wave of 'Korean Child Youth Panel Survey 2010(KCYPS)' and the subjects of this survey were 2,098 1st grade junior middle school students. To measure the variables, this study used such scales as the parenting attitude scale, self-esteem scale, and peer attachment scale and emotional problem scale. The data were analyzed using descriptive statistics, Pearson's correlation and structural equation modeling analysis. Results of structural equation modeling with data indicated that hypothesized structural equation model produced a good fit but, no direct effect between negative parenting attitude and peer attachment. The self-esteem have mediating effect between parenting attitude and peer attachment, emotion problem. The peer attachment have mediating effect between positive parenting attitude and emotion problem but, did not have mediating effect between negative parenting attitude and emotion problem. The implications for counseling and suggestions for future research are discussed.