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Yes / OBJECTIVE: Develop and validate a child and adolescent version of the Three Factor Eating Questionnaire (CTFEQr17), and to assess its psychometric properties and factor structure. We also examined associations between the CTFEQr17 and body mass index (BMI) and food preferences. DESIGN: A two-phase approach was utilised, employing both qualitative and quantitative methodologies. SETTING: Primary and secondary schools, UK. SUBJECTS: In phase 1, 76 children (39 boys; mean age: 12.3±1.4 years) were interviewed to ascertain their understanding of the original TFEQr21 and to develop accessible and understandable items to create the CTFEQr17. In phase 2, 433 children (230 boys; mean age: 12.0±1.7 years) completed the CTFEQr17 and a food preference questionnaire, a subsample (n = 253; 131 boys) had their height and weight measured and 45 children (23 boys) were interviewed to determine their understanding of the CTFEQr17. RESULTS: The CTFEQr17 showed good internal consistency (Cronbach’s α=0.85) and the three factor structure was retained: cognitive restraint (CR), uncontrolled eating (UE) and emotional eating (EE). Qualitative data demonstrated a high level of understanding of the questionnaire (95%). A high CR was found to be significantly associated with a higher body weight, BMI and BMI percentile. High UE and EE scores were related to a preference for high fat savoury and high fat sweet foods. The relationships between CTFEQr17, anthropometry and food preference were stronger in girls compared to boys. CONCLUSIONS: The CTFEQr17 is a psychometrically sound questionnaire for use in children and adolescents, and is associated with anthropometric and food preference measures.

Spatial heterogeneity in the soil system has a profound influence on the flow of water and chemicals in the unsaturated zone. Incorporating intrinsic soil variability and extrinsic variability into root zone leaching models will provide a better representation of pollutant distribution in natural field conditions. In this study, a stochastic framework (SF) was developed to represent spatial variability of soil properties in one-dimensional solute transport models, and implemented with two existing root zone leaching models, Opus and GLEAMS. The accuracy of soil water, bromide and pesticide transport predictions from Opus-SF and GLEAMS-SF was evaluated using field-measured soil water content, bromide and pesticide mass data from a 3.9-ha agricultural field in the Dougherty Plain of Georgia and a 0.05-ha field plot in Nomini Creek watershed in Virginia. Results from the rate-based Opus-SF and capacity-based GLEAMS-SF were compared to determine if there were significant differences in their predictions. In the stochastic approach, the heterogeneous field is conceptualized as a collection of vertical, non-interacting soil columns differing in soil properties. The horizontal variations of soil hydraulic and retention properties in each horizon are treated as random functions of zero transverse spatial correlation length, after accounting for any spatial trends. The spatially variable parameters were generated using the Latin hypercube sampling method, and the stochastic simulation of the model was performed using Monte-Carlo simulation techniques. Statistical tests indicated that Opus-SF and GLEAMS-SF did not predict the central tendency and distribution of depth-averaged soil water content and total pesticide mass observed in the field on most sampling dates. But their predictions were sufficiently accurate for most management-type applications. Soil hydraulic and retention properties derived from texture data at the Nomini Creek site substantially reduced the variability in soil water content predictions from both models, but had less impact on bromide and pesticide mass predictions from both models. The mean values predicted by Opus-SF and GLEAMS-SF were similar, but not equal to those predicted by the deterministic version of the models. Soil water and solute transport predictions from Opus-SF and GLEAMS-SF were not substantially different from corresponding results from the traditional Monte-Carlo approach, although soil water predictions from the two modeling approaches were significantly different for the first 150 days of simulation. Comparison between results from Opus-SF and GLEAMS-SF showed that the distributions and medians of soil water content predicted by the two models were significantly different on most sampling dates. The distributions and medians of pesticide mass predicted by the two models were closer than soil water content, but were significantly different on more than half of the field sampling dates. The more functional GLEAMS-SF model was able to simulate depth-averaged soil water content in the root zone better than the more physically based Opus-SF, although GLEAMS-SF was not able to simulate the depth distribution of soil water as accurately as Opus-SF. GLEAMS-SF was also able to predict solute movement at least as well as Opus-SF. GLEAMS-SF was able to simulate spatial variations of depth-averaged soil water content and pesticide mass in the field with reasonable accuracy employing fewer parameters that exhibit relatively lesser spatial variability. / Ph. D.

The purpose of this study was to develop an instrument to measure the sense of competence of traditional age college students across the dimensions that define the construct. The Sense of Competence Scale-Revised (SCS-R) was developed to provide a measure of Chickering’s (1969) first vector, an important psychosocial construct. Administrators can use data from the instrument to modify an institution’s academic and social environment to enhance the development of the intellectual, physical, and interpersonal competencies of college students. During the development and validation, various aspects of the SCS-R were examined in accordance with the validity framework outlined by Messick (1995). According to Messick (1995), the validity of measures can be examined in terms of six forms of evidence; content, substantive, structural, generalizability, external and consequential. The six forms of evidence function as general standards for all educational measurement (Messick, 1995). During the study the content aspect of validity was addressed through the creation of concept maps and test blueprints. In addition, the content aspect of validity was addressed by creating and selecting items by reviewing the literature and hosting brainstorming sessions, items were then reviewed by student development theory experts, pilot tested, field tested and then items with high technical quality were selected for the final instrument. The substantive aspect of validity was addressed through an analysis of item rating scale functioning, person fit to the measurement scales, and item difficulty. The structural aspect of validity was addressed by evidence of the instrument’s dimensionality. The generalizability aspect of validity was addressed through an analysis of item/person reliability. The evidence generated from the study suggested that the chosen items for the SCS-R provide reliable and valid estimates of a student’ s personal assessment of their intellectual, physical and interpersonal abilities. / Ph. D.

In recent years, the number of exploits targeting software applications has increased dramatically. These exploits have caused substantial economic damages. Ensuring that software applications are not vulnerable to the exploits has, therefore, become a critical requirement. The last line of defense is to test before hand if a software application is vulnerable to exploits. One can accomplish this by testing for the presence of vulnerabilities. This dissertation presents a framework for deriving verification and validation (V&V) strategies to assess the security of a software application by testing it for the presence of vulnerabilities. This framework can be used to assess the security of any software application that executes above the level of the operating system. It affords a novel approach, which consists of testing if the software application permits violation of constraints imposed by computer system resources or assumptions made about the usage of these resources. A vulnerability exists if a constraint or an assumption can be violated. Distinctively different from other approaches found in the literature, this approach simplifies the process of assessing the security of a software application. The framework is composed of three components: (1) a taxonomy of vulnerabilities, which is an informative classification of vulnerabilities, where vulnerabilities are expressed in the form of violable constraints and assumptions; (2) an object model, which is a collection of potentially vulnerable process objects that can be present in a software application; and (3) a V&V strategies component, which combines information from the taxonomy and the object model; and provides approaches for testing software applications for the presence of vulnerabilities. This dissertation also presents a step-by-step process for using the framework to assess software security. / Ph. D.

In an effort to demonstrate the usefulness of personality tests as predictors of job performance, it is common practice to draw a validation sample consisting of individuals who are currently employed on the job in question. It has long been assumed that the results of such a study are appropriately generalized to the setting wherein job candidates respond to personality inventories as an application requirement. The purpose of this manuscript was to critically evaluate the evidence supporting the presumed interchangeability of present-employees and job applicants. Existing research on the use of personality tests in occupational settings is reviewed. Theoretical reasons to anticipate differential response processes and self-report personality profiles according to test-taking status (present employees versus job applicants) are reviewed, as is empirical research examining relevant issues. The question of sample type substitutability is further probed via a quantitative review (meta-analysis) of the criterion-related validity of seven personality constructs (Neuroticism, Extraversion, Openness to Experience, Agreeableness, Conscientiousness, Optimism, and Ambition). Further, the meta-analytic correlations among these personality constructs are estimated. Test-taking status is examined as a moderator of the criterion-related validities as well as the personality construct inter-correlations. Meta-analytic correlation matrices are then constructed on the basis of the job incumbent and the job applicant subgroup results. These correlation matrices are utilized in a simulation study designed to estimate the potential degree of error when job incumbents are used in place of job applicants in a validation study for personality tests. The results of the meta-analyses and the subsequent simulation study suggest that the moderating effect of sample type on criterion-related validity estimates is generally small. Sample type does appear to moderate the criterion-related validity of some personality constructs, but the direction of the effect is inconsistent: in some cases, incumbent validities are larger than applicant validities. Alternatively, incumbent validities sometimes are smaller than applicant validities. Personality construct inter-correlations yield almost no evidence of moderation by sample type. Further, where there are between group differences in the personality construct inter-correlations, these differences have little bearing on the regression equation relating personality to job performance. Despite a few caveats that are discussed, the results are supportive of the use of incumbent samples in personality-test validation research. / Ph. D.

Prescribed burning (Rx) has become increasingly subjected to various regulations. Among these regulations are ordinances that restrict downwind impacts of smoke from prescribed fires. Regulations can severely limit burn managers and private landowners from using Rx as a forest management tool. This research can help us move away from these simplistic regulations, and help promote a regulatory environment in which scientific tools and knowledge are used to prohibit only activities for which the evidence suggests there will be adverse consequences. This research was divided into three parts that consisted of: (1) a pilot validation of the smoke emission model VSMOKE-GIS; (2) review of southeastern states' smoke management guidelines (SMG); and (3) a geographic analysis of Virginian's current SMG. VSMOKE-GIS showed good accuracy in predicting the PM2.5 concentration and location of the smoke plume downwind. Criteria were identified when managing Rx smoke and the strengths, weaknesses, and implications were discussed of the Rx programs. The geographic analysis demonstrated quantitatively how much area may be impacted with minimal apparent benefit. This research should provide a clearer spatial picture of the smoke management barriers associated with Rx on private woodlands in Virginia. These results should be a useful tool in developing a regulatory environment that encourages Rx when the conditions are optimal. We conclude with future recommendations for Virginia. / Master of Science

Development of unmanned vehicles will increase as the need to save lives rises. In both military and civilian applications, humans can be taken out of the loop through the implementation of safe and intelligent autonomous vehicles. Although hardware and software development continue to play a large role in the autonomous vehicle industry, validation of these systems will always be necessary. The ability to test these vehicles thoroughly and efficiently will ensure their proper and flawless operation. On November 3, 2007 the Defense Advanced Research Projects Agency held the Urban Challenge to drive the development of autonomous ground vehicles for military use. This event required vehicles built by teams across the world to autonomously navigate a 60 mile course in an urban environment in less than 6 hours. This thesis addresses the testing aspect of autonomous ground vehicles that exhibit the advanced behaviors necessary for operating in such an event. Specifically, the experiences of Team Victor Tango and other Urban Challenge teams are covered in detail. Testing facilities, safety measures, procedures, and validation methods utilized by these teams provide valuable information on the development of their vehicles. Combining all these aspects results in a proposed testing strategy for autonomous ground vehicles. / Master of Science

In 2000, the U.S. Census Bureau reported that Latinos represented 12.6% of the total population in the United States. It is projected that by 2010 Latinos will account for 15.5% of the population (1,2). Latinos account for 32% of the population in Texas, and specifically in Corpus Christi, Latinos represent 54% of the population (3). The purpose of this study was to compare reported versus actual physical activity among limited resource Latina mothers. This study also aimed to explore the validity of the existing Behavioral Risk Factor Surveillance System (BRFSS) and Seven-Day Physical Activity Recall (PAR) physical activity assessment tools. Fifty-five Latina mothers from a Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) clinic in Corpus Christi, Texas were recruited to participate in this study. Data were collected through a combined (BRFSS and PAR) physical activity questionnaire as well as through step counts using pedometers. BRFSS and PAR reported significantly different levels of moderate physical activity (p=0.0312) using Chi Square tests when appropriate. The response rate in PAR for all levels of activity intensity was higher than BRFSS. There were significant trends between the number of steps reported and BRFSS and PAR moderate physical activity. Further, the majority of subjects who averaged greater than 5,000 steps per day did not perceive themselves to be moderately active in either BRFSS or PAR. These findings question the validity of these physical activity assessment tools with this population. / Master of Science