Combined Damage Influence Prediction of Curved Composite Structural Responses Using VCCT Technique and Experimental Verification

The influences of crack and delamination on the natural frequency and strain energy release rate of the laminated doubly curved shell structure are computed via a commercial finite element tool (ABAQUS). The effect of individual damages (crack and delamination) is modeled using the virtual crack closure technique (VCCT), considering the curvature effect. Initially, the model validity is established by comparing the results with the available results in the open domain. Additionally, the model validity has been verified via in-house experimentation for frequency responses. Further, the natural frequency and strain energy release rate (SERR) have been calculated for the structure to examine the influences of the individual or combined effect of damages by varying the design-dependent input geometrical parameters. The inclusive characteristics of the current model in conjunction with geometrical configurations are summarized for subsequent references.

Car-Following Model Calibration Based on Driving Simulator Data to Study Driver Characteristics and to Investigate Model Validity in Extreme Traffic Situations

In this paper we use traffic data from a driving simulator study to calibrate four different car-following models. We also present two applications for which the calibration results can be used. The first application relied on the advantage that driving simulator data also contain information on driver characteristics, for example, age, gender, or the self-assessment of driver behavior. By calibrating the models for each driver individually, the resulting model parameters could be used to analyze the influence of driver characteristics on driver behavior. The analysis revealed that certain characteristics, for example, self-identification as an aggressive driver, were reflected in the model parameters. The second application was based on the capability to simulate dangerous situations that require extreme driving behavior, which is often not included in datasets from real traffic and cannot be provoked in field studies. The model validity in these situations was analyzed by comparing the prediction errors of normal and extreme driving behavior. The results showed that all four car-following models underestimated the deceleration in an emergency braking scenario in which the drivers were momentarily shocked. The driving simulator study was validated by comparing the calibration results with those obtained from real trajectory data. We concluded that driving simulator data were suitable for the two proposed applications, although the validity of driving simulator studies must always be regarded.

Vocational awareness and aspiration of seafaring students in Taiwan

Purpose This study aims to examine variables and factors in vocational awareness and attitudes that affect the vocational aspiration of seafaring course students who are potential future seafaring employees. Design/methodology/approach A literature review was conducted to identify factors that prompt students in seafaring courses to pursue seafaring careers, followed by a design of preliminary questionnaire questions to survey students’ perception on the conditions of seafaring careers (i.e. vocational awareness) and their intention to pursue a seafaring career (i.e., vocational aspiration). A total of 744 seafaring course students in four Taiwanese universities completed a questionnaire developed according to the previous studies. A structured equation modelling was conducted in this research including model validity, goodness of fit, model correction and mediation effects. Findings With a model consisting of four factors for vocational awareness, three factors for overall attitudes and vocational aspiration as a dependent variable, the results showed that factors of vocational awareness and students’ overall attitudes were significantly correlated, and the factors of overall attitudes exhibit strong mediation effects on vocational aspiration from vocational awareness. The results confirmed that the factors are important determinants for the vocational aspiration of students. Originality/value The findings of this study provide a comprehensive approach to understand students’ seafaring aspiration for the universities, governments and shipping companies. Seafaring policies and management are discussed from the research findings.

Confirmatory Factor Analysis of Knowledge, Attitude, and Behaviour Questionnaire towards Oral Health among Indian Adults

Background: Oral health-related conditions are among the common conditions seen in adults in India. The usage of inappropriate measurement tools that are unvalidated may result in deceptive and imprecise findings that might lead to substandard plans for cessation programs and ineffectiveness. This study was conducted to validate a questionnaire that can assess the factor structure of knowledge, attitude, and behaviour towards oral health among adults in India by confirmatory factor analysis. Methods: Simple random sampling was conducted among adults in India. A total of 260 adults participated in this study. The knowledge, attitude, and behaviour (KAB) questionnaire on oral health was circulated among the adults who were willing to participate in the study after it was explained to them, and the questionnaires were retrieved once they completed. Software R version 3.6 was used to analyse the data of this study. Robust maximum likelihood was utilized for the assessment due to the violation of multivariate normality assumption. For attitude and behaviour domain, a three-factor model was used for measurement model validity and construct validity. Results: The confirmatory factor analysis of the three-factor model for the 26-item KAB questionnaire on oral health gave sufficient goodness-of-fit values and the measurement model exhibited ideal convergent and discriminant validity following model re-specification. The three-factor model was tested to obtain measurement model validity and construct validity for attitude and behaviour domains. The results of this study gave a statistically significant value (p < 0.001), with χ2 (df) values of 39 (7) and 28 (11) for attitude and behaviour domains, respectively. Conclusions: The KAB oral health questionnaire used in this study has a valid measurement model and reliable constructs. It was found to be an ideal tool to measure the KAB towards oral health among adults in India.