Concept drift detection, the identfication of changes in data distributions in streams, is critical to understanding the mechanics of data generating processes and ensuring that data models remain representative through time [2]. Many change detection methods utilize statistical techniques that take numerical data as input. However, many applications produce data streams containing categorical attributes. In this context, numerical statistical methods are unavailable, and different approaches are required. Common solutions use error monitoring, assuming that fluctuations in the error measures of a learning system correspond to concept drift [4]. There has been very little research, though, on context-based concept drift detection in categorical streams. This approach observes changes in the actual data distribution and is less popular due to the challenges associated with categorical data analysis. However, context-based change detection is arguably more informative as it is data-driven, and more widely applicable in that it can function in an unsupervised setting [4]. This study offers a contribution to this gap in the research by proposing a novel context-based change detection and adaptation algorithm for categorical data, namely Fine-Grained Change Detection in Categorical Data Streams (FG-CDCStream). This unsupervised method exploits elements of ensemble learning, a technique whereby decisions are made according to the majority vote of a set of models representing different random subspaces of the data [5]. These ideas are applied to a set of concept drift detector objects and merged with concepts from a recent, state-of-the-art, context-based change detection algorithm, the so-called Change Detection in Categorical Data Streams (CDCStream) [4]. FG-CDCStream is proposed as an extension of the batch-based CDCStream, providing instance-by-instance analysis and improving its change detection capabilities especially in data streams containing abrupt changes or a combination of abrupt and gradual changes. FG-CDCStream also enhances the adaptation strategy of CDCStream producing more representative post-change models.

In recent decades the role of context in food consumption behaviour has been the focus of some research. However little is known about whether context influences the way in which we learn to like foods. Most of our food likes and dislikes are acquired through experience. A number of different processes are thought to be involved. One such mechanism is flavour-flavour evaluative conditioning (EC). In flavour-flavour EC a novel flavour (Conditioned Stimuli; CS) is repeatedly paired with a flavour that already evokes an affective response (Unconditioned Stimuli; US). The outcome of these repeated pairings is a shift in liking towards the CS that is in line with the affective value of the US. There is reason to believe that certain contextual factors may influence this type of food preference learning. However few studies have investigated this. In this thesis the impact of several contextual factors on flavour-flavour EC is explored. We also explore the use of approach behaviour as an indirect measure of liking.Chapters 2 and 3 present evidence of the influence of two external contextual factors in flavour-flavour EC. In Chapter 2 the effect of information was investigated. Conditioning in unrestrained eaters was marginally enhanced when conditioning was presented in the context of positive information regarding the CS-US pairings. Results show that information may influence flavour-flavour EC, possibly through assimilation and contrast effects. In Chapter 3 the effect of physical context on flavour-flavour EC was explored. Results showed that conditioning was context specific. Conditioning effects were strongest when participants acquired conditioning and were tested in the same context compared to those who acquired conditioning in one context and moved to a second context for testing. Chapter 4 presents a methodological investigation of the efficacy of using approach behaviours as a way to indirectly measure liking for real drink stimuli. Approach behaviours were shown to differ according to drink valence with quicker approaches exhibited for pleasant drinks compared to aversive drinks. Approach behaviours were then used as an indirect measure of drink liking in Chapter 5. Chapters 5 and 6 explore two factors related to the internal context. Chapter 5 explores the role of cognitive resources in flavour-flavour EC. In two experiments conditioning was shown to be reduced under conditions of cognitive load suggesting a role for cognitive resources in flavour-flavour EC. Chapter 6 presents an exploration of the effect of mood on flavour-flavour EC. There was no effect of mood on conditioning per se, however results showed that sad participants rated CS flavours more positively than happy participants, a finding that is interpreted with reference to mood regulation. The work presented in this thesis provides evidence that many factors related to the context within which learning occurs can influence flavour-flavour EC. Flavour-flavour EC is shown to be context specific, dependent upon cognitive resources and open to influence from information and mood. These findings highlight the importance of context in food behaviour.

Evaluation use is a complex and multifaceted construct comprising domains of findings and process use and sub-categories of instrumental use, conceptual use, and persuasive (legitimative/symbolic) use. It is an important aspect of evaluation practice which has received much attention from evaluation scholars and practitioners. However, evaluation and evaluation use in countries outside North America, Europe and Australasia is under-investigated. This study proposes to make a modest contribution to understanding evaluation practices in an Asian context through investigating the value and utility of program evaluation as perceived by officials in selected Singapore social sector ministries. Singapore is a democratic country but has retained the characteristics of a highly centralized state. In addition, Confucian values are very important for the political leaders and Singapore society. A modified explanatory sequential mixed methods design was used to address the research questions. Both quantitative and qualitative data were collected through a questionnaire with both closed-ended and open-ended questions. The questionnaire was followed up with interviews to provide additional depth and explanations related to the results from the questionnaire. The questionnaire, based on current theories and the applicability of these evaluation theories to Singapore, was sent through email to officers in two social sector ministries in Singapore - Ministry of Culture, Community and Youth (MCCY) and Ministry of Education (MOE), and 120 valid responses were obtained. Results were analyzed by examining the internal structure and bifactor model underlying the questionnaire. The hypothesized bifactor model comprised a general factor, Perceptions of Evaluation, and two sub-factors – Value of Program Evaluation and Purposes of Program Evaluation. The score on Perceptions of Program Evaluation was regressed on respondents’ background variables to investigate factors that affected their perceptions. Qualitative findings from the open-ended questions and the interviews were analyzed separately and integrated with the quantitative results. The questionnaire functioned well for the respondents, indicating the applicability of existing scholarship on program evaluation to the Singapore context. However, there were a few items that were not respond to as hypothesized. Unique aspects of the context in Singapore social sector ministries might have been the reason for the responses to these items. In addition, the results suggested that a modified bifactor model (with purposes split into internal and external to the program) would fit the data better. On the whole, respondents perceived program evaluation positively (Mean = 1.58, SD = 0.52 on a scale from minus three to three with zero as the mid-point) and emphasized the value of program evaluation for learning and improvement. However, respondents seemed to have reservations with going through the evaluation process. Factors influencing the respondents’ perceptions were layered, and included such factors as officers’ characteristics and experiences, bosses, evaluators, corporate values, organizational structure, societal values and political climate. Officers’ experiences with program evaluation emerged as an important factor, particularly experiences related to benefitting from program evaluation. Given the Confucianism based, highly centralized Singapore state, there might be gaps in current literature to inform and understand the evaluation practices within this and similar contexts. Further studies would be needed to investigate the extent of influence and the mechanisms through which the factors affect perceptions of program evaluation in the Singapore context.

In an increasingly competitive environment, sustaining high performance is critical. Effective performance management can enhance performance to support organisational success. Individuals in organisations want growth, and yet businesses are not leveraging the opportunity to develop them. Literature has identified four elements that influence the effectiveness of performance management. The purpose of this study is to determine the impact that the elements; employees, managers, the performance management system and context, have on the effectiveness of performance management. The study was qualitative and exploratory, involving semi-structured interviews with 22 respondents from four automotive component manufacturers in KwaZulu-Natal. The respondents comprised executives, senior managers, line managers and employees. Each interview was analysed utilising thematic analysis. Findings from the research confirmed the literature that the elements do influence performance management and highlighted two other elements, the human resource department and leadership. The relationships between the elements revealed effects that served as enablers or deterrents to the elements working efficiently. A framework emerged from findings and reviewed literature, which depicts the interconnection of the elements and aspects for businesses to consider, in order to utilise performance management effectively. The findings from this study adds to the existing literature in the field of performance management. / Mini Dissertation (MBA)--University of Pretoria, 2021. / Gordon Institute of Business Science (GIBS) / MBA / Unrestricted

Major Depressive Disorder is regarded as a major contributor to the global burden of disease. It is considered as the fourth highest cause of disability across the globe and second highest between the ages of 15 and 44. It is a serious mental health condition that affects individuals’ physical and mental health and is often associated with comorbidities, functional impairment and at times fatal consequences. Men with depression are considered as an at-risk group as research has shown that males are less likely to receive intervention or health care compared to women, due to hegemonic masculine norms. Within the qualitative research community, some efforts have been made to give voice to men’s experiences of depression and help-seeking, as well as the coping strategies that they deploy to manage such symptoms. However, comparatively little to no research has focused on the South African population, and specifically on Black men’s experiences. Similarly, only a few studies have concentrated on the positive, helpful and/or adaptive coping strategies used by men to manage their internal distress. Thus, this study contributed to a growing body of knowledge and filled a gap in current literature. This research was qualitative in nature and deployed Braun and Clarke’s (2006) six-phase framework for conducting a thematic analysis, in order to analyse the eight individual interviews conducted. The analysis produced various themes and subthemes that elucidated the experiences of masculinity, depression, help-seeking and coping mechanisms among Black men in South Africa. The three overarching themes included: Real men don’t cry; Sadness hurts, but sharing hurts more; and Dark days, take control; all of which were related to several subthemes. The analysis indicated that Black men in South Africa do experience depressed moods and internal distress. However, they may deny such experiences due to their subscription to strength-based masculine ideals. They instead foster a mask of indifference to such pain by denying or supressing their emotions in order to assimilate into masculine norms. This was even more apparent in Black African cultures where hegemonic masculine norms were further entrenched and encouraged. Furthermore, public and self-stigma were commonly cited as a reason why the men in the study felt the need to uphold this image of indifference and keep subscribing to such dogmas. This translated into the men’s experiences and attitudes towards help-seeking, where they would often reject or be reluctant to disclose their emotional distress to professionals or to those closest to them. This was due to the perception that help-seeking is in line with femininity, which diverts/shifts away from the masculine ideals they sought to uphold. Another aspect introduced was how these concepts intertwined with Black African cultures. Namely, it may be more difficult for Black men in South Africa to openly express their experiences of depression or seek help psychologically, as these are Westernised terms and are uncommon in Black communities. However, a more traditionally accepted help-seeking route was to go to a traditional healer or Sangoma. Considering the men’s overall reluctance to seek help, they engaged in coping strategies in order to manage depressed feelings, as this was more in line with the masculinity expectations of autonomy, unemotionality and problem solving. Negative coping mechanisms were seen as a celebrated and normalized way for men to numb or supress their emotional distress, while still enacting masculinity. Lastly, although positive coping strategies were posited as a way for men to directly engage in distressful emotions, this was more difficult to adopt as they were perceived to be aligned with more feminine traits. This research created a framework that can be used to conceptualise Black South African men’s experiences of depression, help-seeking and coping strategies. This research is of utmost importance considering that men are noted to be more likely to experience functional impairments or fatal consequences due to their reticence for help-seeking. As such, men and future public health messaging could capitalise on this research in order to improve help-seeking and self-management behaviour amongst this population. This is particularly relevant considering our current context of the COVID-19 global pandemic. Keywords: Major Depressive Disorder, South African men, help-seeking, coping strategies, and qualitative thematic analysis. / Mini Dissertation (MA)--University of Pretoria, 2021. / Psychology / MA (Clinical Psychology) / Unrestricted

The study of construct validity is particularly relevant in the twenty-first century, as more and more entities in South Africa are using psychometric instruments – instruments which have to be valid and reliable in accordance with the requirements of the Health Professions Council of South Africa (HPCSA). Even though validity and reliability, together with their accompanying aspects, are the two main considerations of a psychometric instrument, the construct validity of an instrument is one of the most important aspects to consider. This study’s focus is therefore, for the most part, based on the construct validity of the Life-Style Questionnaire. Even though the Life-Style Questionnaire is not a very distinguished questionnaire in the South African context, it is, however, a classified and useable questionnaire to determine into which of the five trait-descriptive lifestyle categories an individual belongs. In recent years, the Professional Board has become increasingly concerned about the misuse of assessment measures in South Africa, while recognising the important role of psychological assessment in the professional practice of psychology, as well as for research purposes (Foxcroft&Roodt, 2005:20). The need therefore existed to determine whether or not the Life-Style Questionnaire actually measures what it is supposed to measure, in other words to determine its construct validity. “The Life-Style Questionnaire was developed as an objective means to measure into which of five trait-descriptive lifestyle categories (aggressive, conforming, defensive, individualistic, or resistive) participants belong” (Driscoll&Eckstein, 2007:1). The purpose of this study was to determine the construct validity of the Life-Style Questionnaire, developed by Driscoll and Eckstein, in the South African -Questionnaire, developed by Driscoll and Eckstein, in the South African context. A quantitative descriptive survey design was used to conduct the research. The Life- Style Questionnaire was administered to a non-probability convenience sample consisting of 301 individuals living in South Africa and the results were subjected to factor analysis (FA), item analysis and confirmatory factor analysis (CFA). Various iterations of the (FA) indicated the primary factors for each of the components of the Life-Style Questionnaire. The final FA yielded a questionnaire consisting of five factors. This was confirmed through Kaiser’s eigenvalues and Cattell’s scree plot. The item analysis indicated that it should be considered to remove items 2, 3, 5, 7, 12, 27, 28, 30 and 32 from the Life-Style Questionnaire. After the factor and item analysis, a CFA was conducted. The purpose of the CFA was to determine whether the postulated theoretical model actually fits the observed data. The most common test used to measure the goodness-of-fit of an instrument is the chi-square test. The chi-square test was conducted by using the EQS programme. The results indicated a poor model fit. However, the reliability of the Life-Style Questionnaire was determined and a Cronbach alpha of 0.853 established the instrument’s high level of reliability. Thus, the Life-Style Questionnaire is a reliable, but invalid instrument. This research study contributed to the understanding and importance of construct validity in psychological instruments. It is important to realise that instruments do not necessarily measure what they are intended to measure and therefore they have to be investigated. Lastly, this study not only emphasises the importance of psychometric properties of psychological instruments, but also the important role that psychometrists and industrial psychologists play with regard to the development and use such instruments. / Dissertation (MCom)--University of Pretoria, 2011. / Human Resource Management / unrestricted

Cross-site scripting (XSS) flaws are a class of security flaws particular to web applications. XSS flaws generally allow an attacker to supply affected web application with a malicious input that is then included in an output page without being properly encoded (sanitized). Recent advances in web applica- tion technologies and web browsers introduced various prevention mechanisms, narrowing down the scope of possible XSS attacks, but those mechanisms are usually selective and prevent only a subset of XSS flaws. Among the types of XSS flaws that are largely omitted are the context- sensitive XSS flaws. A context-sensitive XSS flaw occurs when the potentially malicious input is sanitized by the affected web application before being included in the output page, but the sanitization is not appropriate for the browser con- text of the sanitized value. Another type of XSS flaws, which is already better known, but still insufficiently prevented, are the stored XSS flaws. Applica- tions affected by the stored XSS flaws store the unsafe client input in persistent storage and return it in another HTTP response to (possibly) another client. Our work is focused on advancing state-of-the-art automated detection of those two types of XSS flaws using various analysis techniques ranging from purely static analysis to dynamic graybox analysis.

Context-aware computing aims at making mobile devices sensitive to the social and physical settings in which they are used. A necessary requirement to achieve this goal is to enable those devices to establish a shared understanding of the desired settings. Establishing a shared understanding entails the need to manipulate sensed data in order to capture a real world situation wholly, conceptually, and meaningfully. Quite often, however, the data acquired from sensors can be inexact, incomplete, and/or uncertain. Inexact sensing arises mostly due to the inherent limitation of sensors to capture a real world phenomenon precisely. Incompleteness is caused by the absence of a mechanism to capture certain real-world aspects; and uncertainty stems from the lack of knowledge about the reliability of the sensing sources, such as their sensing range, accuracy, and resolution. The thesis identifies a set of criteria for a context-aware system to capture dynamic real-world situations. On the basis of these criteria, a distributed architecture is designed, implemented and tested. The architecture consists of Primitive Context Servers, which abstract the acquisition of primitive contexts from physical sensors; Aggregators, to minimise error caused by inconsistent sensing, and to gather correlated primitive contexts pertaining to a particular entity or situation; a Knowledge Base and an Empirical Ambient Knowledge Component, to model dynamic properties of entities with facts and beliefs; and a Composer, to reason about dynamic real-world situations on the basis of sensed data. Two additional components, namely, the Event Handler and the Rule Organiser, are responsible for dynamically generating context rules by associating decision events ? signifying a user?s activity ? with the context in which those decision events are produced. Context-rules are essential elements with which the behaviour of mobile devices can be controlled and useful services can be provided. Four estimation and recognition schemes, namely, Fuzzy Logic, Hidden Markov Models, Dempster-Schafer Theory of Evidence, and Bayesian Networks, are investigated, and their suitability for the implementation of the components of the architecture of the thesis is studied. Subsequently, fuzzy sets are chosen to model dynamic properties of entities. Dempster-Schafer?s combination theory is chosen for aggregating primitive contexts; and Bayesian Networks are chosen to reason about a higher-level context, which is an abstraction of a real-world situation. A Bayesian Composer is implemented to demonstrate the capability of the architecture in dealing with uncertainty, in revising the belief of the Empirical Ambient Knowledge Component, in dealing with the dynamics of primitive contexts and in dynamically defining contextual states. The Composer could be able to reason about the whereabouts of a person in the absence of any localisation sensor. Thermal, relative humidity, light intensity properties of a place as well as time information were employed to model and reason about a place. Consequently, depending on the variety and reliability of the sensors employed, the Composer could be able to discriminate between rooms, corridors, a building, or an outdoor place with different degrees of uncertainty. The Context-Aware E-Pad (CAEP) application is designed and implemented to demonstrate how applications can employ a higher-level context without the need to directly deal with its composition, and how a context rule can be generated by associating the activities (decision events) of a mobile user with the context in which the decision events are produced.

The objective of this study was to assess the psychometric properties of the Burnout Inventor for employees in a selected organization in South Africa. A purposive, non-probability sample was used (N = 365). The Burnout Inventory and a biographical questionnaire were administered. Exploratory factor analysis with target rotations confirmed the construct equivalence of the questionnaire. Two internally consistent factors, namely, Organisation and Work-context were extracted. AFRIKAANS : Die doelstelling van hierdie studie was om die psigometriese eienskappe van die Burnout Inventory vir werknemers in n geselekteerde organisasie in Suid- Afrika te bepaal. ‘n Doelgerigte nie-waarskynlikheidsteekproef is gebruik (N = 365). Die Burnout Inventory en biografiese vraelys is afgeneem. Verkennende Faktoranalise met teikenrotasies het die konstrukekwivalensie van die vraelys bevestig. Twee interne konsekwente faktore, organisasie en werkskonteks is onttrek. Copyright 2007, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Karodia, TR 2007, Psychometric properties of the burnout inventory, MCom dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-02222012-110515 / > C12/4/198/gm / Dissertation (MCom)--University of Pretoria, 2007. / Human Resource Management / unrestricted

Today a large percentage of the population uses a handheld (either a mobile phone or a PDA) a laptop computer, or some other computing device. As this penetration increases, the user wants to take as great an advantage of these devices as possible. It is for that reason that communication is demanded almost everywhere. Simply having continuous access to the network is no longer sufficient thus context awareness and easy accessibility are becoming more and more relevant. The idea of this masters thesis is to explore these ideas building on the prior work of Maria José Parajón Domínguez. The devices used for this study will be an HP iPAQ h5550 and a laptop. A client-server application, whose components will be explained in detail in further sections, was designed to study some factors that may be taken into account when trying to satisfy the users´ demands as stated above. One of these factors could be, for example, what are the effects of having a personal voice interface on the traffic to and from the user’s mobile device. The aim of this voice interface will be to provide more freedom to the user and also satisfy the demand for greater accessibility and facilitate mobile usage, not only for the common user, but also for handicapped people. Regarding the user’s desire to always have connectivity everywhere, we wish to examine the effects on the traffic to and from the user’s handheld, when exploiting significant local storage. Also related to the requirements on current devices to be always and everywhere connected and the huge amount of resources that this entails, it will be of interest to study the possibility of exchanging personalized CODECs (in the extreme case exchanging voice synthesis modules) and how this might affect traffic to and from the user’s mobile device. This last method could potentially greatly reducing both the demands on the communication links and the cost of this connectivity. With all these ideas in mind, this thesis aims to research an area that is nowadays continuously attracting new users and the goal is to find solutions to the demands that have resulted for these trends. / Användningen av portabla elektroniska apparater så som mobiltelefoner, handdatorer med mera är nu för tiden vida utbrett. Ju fler apparater som används desto större blir efterfrågan efter mobila tjänster för dessa. Som ett resultat ökar behovet av goda kommunikationslösningar, ofta mer komplexa än endast kontinuerlig dataåtkomst. Syftet med detta examensarbete är att fortsätta att utforska de idéer som Maria José Parajón Domínguez presenterat. För att utföra detta kommer en HP iPAQ h5550 och en bärbar dator att användas. En klient-server applikation kommer att tas fram för att undersöka några faktorer som påverkar kommunikationslösningarna. Ett exempel på en sådan faktor skulle kunna vara effekten av att ha ett personligt röstgränssnitt för trafiken. Syftet med detta gränssnitt skulle vara att erbjuda användaren större frihet och flexibilitet för sitt mobilanvändande, oavsett om användaren lider av något handikapp eller ej. Försök kommer även att göras med att lagra mycket data lokalt på användarens apparat, detta i ett försök att minska datatrafiken då många apparater kräver ständig och intensiv datakommunikation. Det är även av intresse att studera möjligheten av utbyte av personliga algoritmer, så kallade CODEC, och hur dessa skulle kunna påverka datatrafiken till och från den portabla apparaten. Det genomgående syftet för alla dessa faktorer är att sänka belastningen på de kommunikationslänkar som utnyttjas. Målet med denna studie är att undersöka några sätt att möta den ökade belastning på kommunikationssystemen som väntas om trenden för mobilt användande ökar.