La modélisation par équations structurelles est très répandue dans des domaines très variés et nous l'appliquons pour la première fois en métrologie dans le traitement de données de comparaisons interlaboratoires. Les modèles à équations structurelles à variables latentes sont des modèles multivariés utilisés pour modéliser des relations de causalité entre des variables observées (les données). Le modèle s'applique dans le cas où les données peuvent être regroupées dans des blocs disjoints où chaque bloc définit un concept modélisé par une variable latente. La structure de corrélation des variables observées est ainsi résumée dans la structure de corrélation des variables latentes. Nous proposons une approche bayésienne des modèles à équations structurelles centrée sur l'analyse de la matrice de corrélation des variables latentes. Nous appliquons une expansion paramétrique à la matrice de corrélation des variables latentes afin de surmonter l'indétermination de l'échelle des variables latentes et d'améliorer la convergence de l'algorithme de Gibbs utilisé. La puissance de l'approche structurelle nous permet de proposer une modélisation riche et flexible des biais de mesure qui vient enrichir le calcul de la valeur de consensus et de son incertitude associée dans un cadre entièrement bayésien. Sous certaines hypothèses l'approche permet de manière innovante de calculer les contributions des variables de biais au biais des laboratoires. Plus généralement nous proposons un cadre bayésien pour l'amélioration de la qualité des mesures. Nous illustrons et montrons l'intérêt d'une modélisation structurelle des biais de mesure sur des comparaisons interlaboratoires en environnement. / Structural equation modelling is a widespread approach in a variety of domains and is first applied here to interlaboratory comparisons in metrology. Structural Equation Models with latent variables (SEM) are multivariate models used to model causality relationships in observed variables (the data). It is assumed that data can be grouped into separate blocks each describing a latent concept modelled by a latent variable. The correlation structure of the observed variables is transferred into the correlation structure of the latent variables. A Bayesian approach of SEM is proposed based on the analysis of the correlation matrix of latent variables using parameter expansion to overcome identifiability issues and improving the convergence of the Gibbs sampler. SEM is used as a powerful and flexible tool to model measurement bias with the aim of improving the reliability of the consensus value and its associated uncertainty in a fully Bayesian framework. The approach also allows to compute the contributions of the observed variables to the bias of the laboratories, under additional hypotheses. More generally a global Bayesian framework is proposed to improve the quality of measurements. The approach is illustrated on the structural equation modelling of measurement bias in interlaboratory comparisons in environment.

Considérant les effets négatifs sur le développement des enfants associées à l'utilisation de châtiments corporels, un ensemble considérable de la recherche a tenté de proposer une avenue pour interrompre le cercle vicieux de la violence intergénérationnelle. Toutefois, on pourrait argumenter qu`une limitation majeure dans la plupart de ces études réside dans le fait que très peu d`entre eux ont eu comme but d`investiguer l'importance d`une troisième variable comme le sentiment de mériter le châtiment, les explications reçues sur l`équité de la peine imposée ou les attitudes qu`une personne peut garder envers cette méthode éducative. En utilisant la modélisation d'équations structurelles, la présente étude a démontré que la relation apparente entre les variables subjectives et sociodémographiques liés à l`expérience de la punition corporelle et l`intention de faire recours à cette méthode éducative en tant que parent est en fait expliquée par le rôle de médiation joué par d'autres variables telles que les attitudes à l'égard de châtiments corporels, le type de châtiments corporels, la façon dont le châtiment a été perçu par le sujet et les raisons données par l'agent pour motiver la peine infligée. La thèse principale avancée par le présent étude est à l`effet qu`une fois le rôle d`une troisième variable est considéré dans l`équation (par exemple, l'attitude envers les châtiments corporels), l'apparente relation entre les variables objectives et les résultats final, soit l`intention de recourir a la punition corporelle, disparaît. Plus précisément, comme il en résulte de l’analyse de modélisation, ce sont les médiateurs qui expliquent toute association possible entre les variables objectives et l`intention d'utiliser les châtiments corporels. C'est-à-dire, un modèle qui ne contiennent aucune liaison directe entre les variables objectives, et directement mésurables (c'est-à-dire l`âgé lors de la punition, le fait d'être un immigrant, la fréquence de la peine, le nombre d'objets utilisés, le nombre d`agents punisseurs, le sexe) et l'intention d'utiliser les châtiments corporels correspond aux données. De surcroît, parmi les quatre médiateurs pris en compte dans notre modèle, ce sont les opinions à l`égard de la punition corporelle qui possèdent la meilleure capacité prédictive en ce qui a trait à l`intention de recourir aux châtiments corporels. Finalement, afin d'étudier le profil des différences entre les sujets en fonction de leurs expériences passées avec les châtiments corporels, les explications reçues pour la peine, et leurs attitudes, une analyse par groupe a été employée. Bref, une solution en quatre groupes faisant des distinctions significatives entre les groupes a été choisie. / Considering the negative developmental findings associated with the use of parental corporal punishment, a considerable body of research has attempted to suggest an avenue for interrupting this vicious cycle of intergenerational violence. However, a major limitation in most of these studies has to do with the fact that very few of them has looked at the influence of a third variable such as the use of explanation, perceived fairness and deservedness of punishment, or the attitudes one has towards corporal punishment. By employing structural equation modelling (SEM), the present study has demonstrated that the apparent relationship between subjective and socio-demographic variables related to corporal punishment and latter intention to use it as a parent is in fact explained by the mediating role of other variables such as attitudes towards corporal punishment, type of corporal punishment, perceived reasons for punishment and reasons given for punishment by the agent. Our main contention was that when a third variable (e.g., attitude towards corporal punishment) is included in the equation, the apparent relationship between punishment variables and outcome disappears. More specifically, as it has resulted from the SEM analysis, the mediating variables explain all of the association between the objective variables and intention to use corporal punishment. That is to say, a model containing no direct paths from the independent variables (i.e., number of ages punished, being an immigrant, frequency of punishment, means of administration of corporal punishment , number of punishing agents, sex) to Intention to Use Corporal Punishment fits the data. Moreover, among the four mediators considered in our model only the attitudinal measures make a significant contribution to the prediction of intention to use corporal punishment. In addition, in order to explore the profile of differences between subjects on their past experiences with corporal punishment, explanations for punishment, and present attitudes, cluster analysis was employed. Finally, a four cluster solution that made meaningful distinctions between groups was selected for consideration. / Les analyses statistiques ont été réalisées avec le logiciels SPSS 11.0(Statistical Package for Social Sciences) et AMOS 6 (Analysis of Moment Structures. La base de données de l'étude a été crée et receuillie par Caroline Despatie en collaboration avec Dr. Dianne Casoni.

The thesis is based on the Kidscreen Follow-up study. A representative sample of Spanish adolescents and youths and one of their parents were assessed twice (3 years apart) to evaluate adolescents and youths health related quality of life and mental health. The specific objectives of this thesis were to assess the effect of life events, and family and social variables (parents' mental health and home life) on three different health related outcomes: heath related quality of life, mental health, and psychosomatic complaints of adolescents and youths. The Coddington Life Events Scales were adapted into Spanish using the translation and back-translation process. Multiple linear regression and structural equation modelling were used to analyze the effect of the determinants selected. Life events and parents' mental health acted as risk factors for the outcomes selected, specially on mental health outcomes, whereas family factors like the relation with family members in home life were protective factors. Social factors inside the family should be promoted and reinforced to protect adolescents and youths from the effect of risk factors. / Aquesta tesi és part de l'estudi KIDSCREEN Follow-up. Utilitzant una mostra representativa d'adolescents i joves de l'estat espanyol, es van mesurar diferents aspectes relacionats amb la salut, avaluant la mostra dues vegades (amb una separació de 3 anys). Concretament, l'objectiu de la tesi va ser avaluar l'efecte dels aconteixements vitals i factors familiars i socials (salut mental dels pares i vida familiar) en tres resultats en salut: la qualitat de vida relacionada amb la salut, la salut mental i els problemes psicosomàtics dels adolescents i joves. Per això, es va adaptar l'escala Coddington Life Events Scales seguint la metodologia de traducció-retrotraducció. Es van utilizar models de regressió i models d'equacions estructurals per analitzar l'efecte dels determinants en salut. Els aconteixements vitals i la salut mental dels pares van ser dos factors de risc importants, especialment en la salut mental dels adolescents i joves. Per altra banda, les variables familiars com la relació dels membres de la família van actuar com a factors protectors. La cohesió dels membres de la família s'ha de promoure per tal de protegir els adolescents i joves de l'efecte de factors de risc.

In the shift to a globalised creative economy where innovation and creativity are increasingly prized, many studies have documented direct and indirect social and economic benefits of the arts. In addition, arts workers have been argued to possess capabilities which are of great benefit both within and outside the arts, including (in addition to creativity) problem solving abilities, emotional intelligence, and team working skills (ARC Centre of Excellence for Creative Industries and Innovation, 2007). However, the labour force characteristics of professional artists in Australia and elsewhere belie their importance. The average earnings of workers in the arts sector are consistently less than other workers with similar educational backgrounds, and their rates of unemployment and underemployment are much higher (Australian Bureau of Statistics, 2005; Caves, 2000; Throsby & Hollister, 2003). Graduating students in the arts appear to experience similar employment challenges and exhibit similar patterns of work to artists in general. Many eventually obtain work unrelated to the arts or go back to university to complete further tertiary study in fields unrelated to arts (Graduate Careers Council of Australia, 2005a). Recent developments in career development theory have involved discussion of the rise of boundaryless careers amongst knowledge workers. Boundaryless careers are characterised by non-linear career progression occurring outside the bounds of a single organisation or field (Arthur & Rousseau, 1996a, 1996b). The protean career is an extreme form of the boundaryless career, where the careerist also possesses strong internal career motivations and criteria for success (Baruch, 2004; Hall, 2004; Hall & Mirvis, 1996). It involves a psychological contract with one's self rather than an organisation or organisations. The boundaryless and protean career literature suggests competencies and dispositions for career self-management and career success, but to date there has been minimal empirical work investigating the predictive value of these competencies and dispositions to career success in the boundaryless or protean career. This program of research employed competencies and dispositions from boundaryless and protean career theory to predict career success in professional artists and tertiary arts graduates. These competencies and dispositions were placed into context using individual and contextual career development influences suggested by the Systems Theory Framework of career development (McMahon & Patton, 1995; Patton & McMahon, 1999, 2006a). Four substantive studies were conducted, using online surveys with professional artists and tertiary arts students / graduates, which were preceded by a pilot study for measure development. A largely quantitative approach to the program of research was preferred, in the interests of generalisability of findings. However, at the time of data collection, there were no quantitative measures available which addressed the constructs of interest. Brief scales of Career Management Competence based on the Australian Blueprint for Career Development (Haines, Scott, & Lincoln, 2003), Protean Career Success Orientation based on the underlying dispositions for career success suggested by protean career theory, and Career Development Influences based on the Systems Theory Framework of career development (McMahon & Patton, 1995; Patton & McMahon, 1999, 2006a) were constructed and validated via a process of pilot testing and exploratory factor analyses. This process was followed by confirmatory factor analyses with data collected from two samples: 310 professional artists, and 218 graduating arts students who participated at time 1 (i.e., at the point of undergraduate course completion in October, 2005). Confirmatory factor analyses via Structural Equation Modelling conducted in Study 1 revealed that the scales would benefit from some respecification, and so modifications were made to the measures to enhance their validity and reliability. The three scales modified and validated in Study 1 were then used in Studies 3 and 4 as potential predictors of career success for the two groups of artists under investigation, along with relevant sociodemographic variables. The aim of the Study 2 was to explore the construct of career success in the two groups of artists studied. Each participant responded to an open-ended question asking them to define career success. The responses for professional artists were content analysed using emergent coding with two coders. The codebook was later applied to the arts students' definitions. The majority of the themes could be grouped into four main categories: internal definitions; financial recognition definitions; contribution definitions; and non-financial recognition definitions. Only one third of the definition themes in the professional artists' and arts graduates' definitions of career success were categorised as relating to financial recognition. Responses within the financial recognition category also indicated that many of the artists aspired only to a regular subsistence level of arts income (although a small number of the arts graduates did aspire to fame and fortune). The second section of the study investigated the statistical relationships between the five different measures of career success for each career success definitional category and overall. The professional artists' and arts graduates' surveys contained several measures of career success, including total earnings over the previous 12 months, arts earnings over the previous 12 months, 1-6 self-rated total employability, 1-6 self-rated arts employability, and 1-6 self-rated self-defined career success. All of the measures were found to be statistically related to one another, but a very strong statistical relationship was identified between each employability measure and its corresponding earnings measure for both of the samples. Consequently, it was decided to include only the earnings measures (earnings from arts, and earnings overall) and the self-defined career success rating measure in the later studies. Study 3 used the career development constructs validated in Study 1, sociodemographic variables, and the career success measures explored in Study 2 via Classification and Regression Tree (CART - Breiman, Friedman, Olshen, & Stone, 1984) style decision trees with v-fold crossvalidation pruning using the 1 SE rule. CART decision trees are a nonparametric analysis technique which can be used as an alternative to OLS or hierarchical regression in the case of data which violates parametric statistical assumptions. The three optimal decision trees for total earnings, arts earnings and self defined career success ratings explained a large proportion of the variance in their respective target variables (R2 between 0.49 and 0.68). The Career building subscale of the Career Management Competence scale, pertaining to the ability to manage the external aspects of a career, was the most consistent predictor of all three career success measures (and was the strongest predictor for two of the three trees), indicating the importance of the artists' abilities to secure work and build the external aspects of a career. Other important predictors included the Self management subscale of the Career Management Competence scale, Protean Career Success Orientation, length of time working in the arts, and the positive role of interpersonal influences, skills and abilities, and interests and beliefs from the Career Development Influences scale. Slightly different patterns of predictors were found for the three different career success measures. Study 4 also involved the career development constructs validated in Study 1, sociodemographic variables, and the career success measures explored in Study 2 via CART style decision trees. This study used a prospective repeated measures design where the data for the attribute variables were gathered at the point of undergraduate course completion, and the target variables were measured one year later. Data from a total of 122 arts students were used, as 122 of the 218 students who responded to the survey at time 1 (October 2005) also responded at time 2 (October 2006). The resulting optimal decision trees had R2 values of between 0.33 and 0.46. The values were lower than those for the professional artists' decision trees, and the trees themselves were smaller, but the R2 values nonetheless indicated that the arts students' trees possessed satisfactory explanatory power. The arts graduates' Career building scores at time 1 were strongly predictive of all three career success measures at time 2, a similar finding to the professional artists' trees. A further similarity between the trees for the two samples was the strong statistical relationship between Career building, Self management, and Protean Career Success Orientation. However, the most important variable in the total earnings tree was arts discipline category. Technical / design arts graduates consistently earned more overall than arts graduates from other disciplines. Other key predictors in the arts graduates' trees were work experience in arts prior to course completion, positive interpersonal influences, and the positive influence of skills and abilities and interests and beliefs on career development. The research program findings represent significant contributions to existing knowledge about artists' career development and success, and also the transition from higher education to the world of work, with specific reference to arts and creative industries programs. It also has implications for theory relating to career success and protean / boundaryless careers.

The potential of small and medium enterprises (SMEs) in promoting economic growth in both developed and developing countries is widely accepted and documented by both scholars and policy makers. Particularly lacking are studies on the evidence in support of the importance of credit rationing to the sustainability of SMEs in an emerging economy like South Africa’s. This specific problem, especially in the developing countries, has been identified as the major bottleneck in realising socio-economic potentials of SMEs in those countries. However, one of the major ways of addressing the challenge of inadequate funding that exists within the SME sector is the use of bank credit. This study was therefore undertaken to explore the role of commercial banks in the provision of credit to the SMEs in South Africa. This study focuses on the issue of the relationship between the banking industry and SMEs. In particular, the problem of credit rationing of, and discrimination against SMEs by commercial banks was investigated. Because credit rationing and finance gaps can stem from imperfections on either supply-side (banks), or demand-side (SMEs), or both, the intention of the study was to examine both of these variables in order to uncover the implications of their relationships. The empirical analysis is based on survey data collected by means of a structured questionnaire which was distributed amongst banks and SME borrowers in the Gauteng Province of South Africa. Contrary to the general view that commercial banks are disinclined to provide credit to SMEs, the study found that South African banks are keen to serve the SMEs and are therefore making efforts to penetrate this potentially profitable market segment. However, several obstacles are potentially restricting the involvement of banks with SMEs in South Africa. The findings revealed that regulations such as the Financial Intelligence Centre Act (FICA) and the National Credit Act (NCA) came out strongly as major hindrances of bank financing to SMEs. Furthermore, it was shown that compliance with the NCA was ranked higher than credit history and profitability as a factor hindering the approval of SME loans. - iii - However, by using the structural equation modelling (SEM), the results also show that there is a positive and significant influence of lending technology and collateral on the supply of credit to SMEs. Variables such as creditworthiness, collateral and e-banking were found to have a positive and significant impact on the provision of credit to SMEs by commercial banks. For both the supply- and demand-side analysis, technology came out as the most important predictor of SME access to finance. This means that banks should strive to align their lending techniques with the dynamic technological developments so as to reach as many SMEs as possible even in the geographically dispersed regions. It is anticipated that improving SME access to bank credit could be the key to the growth and sustainability of SMEs, the alleviation of poverty and unemployment; and consequently leading to the growth of the South African economy. / Business Management / D. Com. (Business Management)

School physical science is a prerequisite for science courses at institutions of higher education. Science graduates are an important link in a nation's scientific and technological development which often shapes a country's economic development. The purpose of this study was to investigate psychological and social factors influencing physical science achievement and attitude of black secondary school students in South Africa. The first part of the literature study which was concerned with physical science education in South Africa revealed that few black students chose to study science after standard seven, that failure rates were high and that science education was generally in a state of crisis. The second part of the literature study identified psychological and social factors related to science achievement and attitude. These were home environment variables, teacher and school related variables, personal variables (self-concept, motivation, gender, ethnicity) and students' abilities. The third part was the construction of a Structural Equation Model (SEM) specifying the relationships among the psychological and social factors and their effects on physical science achievement and attitude. The theoretical SEM fit the data reasonably well. The best fitting model, however, was a revised model in which several paths were constrained. The latter accounted for a substantial variance in attitude towards physical science (70.3%) and a meagre 17.7% in physical science achievement. The variables ability, home environment and self-concept had the greatest total effects on physical science achievement. Self-concept, home environment and motivation made the greatest total contributions to physical science attitude. Teacher characteristics and school environment had non-significant effects on physical science achievement and attitude. Multiple-group structural equation modelling analyses found no significant difference in the structural parameters of boys and girls. Theoretical and educational implications of the findings were discussed and specific recommendations for improving educational practice in general and physical science achievement and attitude in particular, were made. / Psychology of Education / D. Ed. (Psychology of Education)

Text in English / Regular exercise has significant physical and psychological health benefits yet, paradoxically, may also have harmful effects. The purpose of this study was to investigate the physical and psychological health risks of distance running, a popular participation sport in South Africa. Structural equation modelling was employed to examine the personality and motivational antecedents of running addiction and its influence, in turn, on self-reported overuse injuries and upper respiratory tract infections in 220 athletic club members. The predictors and physical health effects of customary training load were also assessed. It was found that perfectionistic concerns, Type A behaviour pattern, and task goal orientation had a direct, positive impact on running addiction, which predicted higher running injury scores. In contrast, training workload (Volume × Intensity) was inversely related to injury risk. Neither running addiction nor any training load variables influenced infectious illness susceptibility. The findings of this study indicate that maladaptive perfectionism, Type A behaviour, and achievement goal orientation may be risk factors for running addiction, which may, in turn, contribute to increased injury incidence in South African distance runners. Conversely, heavier training loads may be protective against injury occurrences in this population. The results of this research may help to enhance current understanding of the possible health hazards of distance running. This knowledge may have practical implications for the health and well-being of runners of diverse levels of ability and experience. / Psychology / D.Litt. et Phil. (Psychology)

The purpose of the study was to identify and transform, as necessary, constructs of communication satisfaction and to develop a hybrid quantitative audit of organisational communication satisfaction for collectivist contexts that is both reliable and valid, using Amos Graphics for structural equation modelling. The objective was also to develop a full latent variable model and to test its fitness to the data collected from a random sample of civil servants across Addis Ababa’s civil service bureaus. The study comprised three sequential parts, namely pilot, exploratory factor analysis (EFA) (Main Study One) and confirmatory factor analysis (CFA) (Main Study Two). These were used as per the existing framework in instrument development and validation. The pilot study indicated the need for more robust data. After a series of tests, principal factor axis factoring with oblique rotation was used as the most appropriate for perceptual data, out of several options on the EFA menu. The initially hypothesised six-factor solution with the dimensions of horizontal communication, personal feedback, supervisory communication, communication climate, relational trust and job satisfaction was found to be unfit for the data on conceptual and statistical grounds and psychometric analyses which involved the use of eigenvalues and the scree plot. A more appropriate two-factor solution based on the more precise parallel analysis strategy was consistent with current research that communication satisfaction is best conceptualised in terms of informational and relational domains as operationalised using the EFA procedure. The two-factor solution led to the formation of a 17-item scale out of the original 30-item measure, with two latent dimensions namely relational satisfaction and informational satisfaction. The items of the new EFA-generated organisational communication satisfaction scale were renumbered consecutively and the scale was cross-validated on a xiv new sample of 288 civil servants from the Addis Ababa City Administration. The cross-validation necessitated model respecification and re-estimation. The respecified model underwent validation at different levels. All seven aspects of validity, namely content validity, construct validity, factorial validity, reliability, convergent validity, discriminant validity and nomological validity, were addressed and found to be adequate. However limitations are also indicated as avenues for further enquiry. / Communication Science / D. Litt. et Phil. (Communication)

No description available.

Brand loyalty is seen as a repeat purchase and also the ability to recommend services or products. Telecommunication service providers require loyal customers to stay in business. The current thesis examines the impact of how brand function and corporate image create loyalty in North America, Europe, and Africa's telecom service providers. The researcher employed an anonymous online survey in Africa, Europe, and North America. A total of 971 responses were received. Using Partial Least Square regression analysis, the research examined the relationship between the variables: Brand Function, Corporate Image and Loyalty. The study found that brand function and corporate image has a significant positive effect on customer satisfaction. In addition, the research used machine learning algorithm to model the best prediction for consumer recommendation of products and services through their telecommunication service provider to friends and family. / School of Computing / M. Sc. (Computing)