Nous nous intéressons à la résolution de systèmes linéaires creux de très grande taille par des méthodes directes de factorisation. Dans ce contexte, la taille de la matrice des facteurs constitue un des facteurs limitants principaux pour l'utilisation de méthodes directes de résolution. Nous supposons donc que la matrice des facteurs est de trop grande taille pour être rangée dans la mémoire principale du multiprocesseur et qu'elle a donc été écrite sur les disques locaux (hors-mémoire : OOC) d'une machine multiprocesseurs durant l'étape de factorisation. Nous nous intéressons à l'étude et au développement de techniques efficaces pour la phase de résolution après une factorization multifrontale creuse. La phase de résolution, souvent négligée dans les travaux sur les méthodes directes de résolution directe creuse, constitue alors un point critique de la performance de nombreuses applications scientifiques, souvent même plus critique que l'étape de factorisation. Cette thèse se compose de deux parties. Dans la première partie nous nous proposons des algorithmes pour améliorer la performance de la résolution hors-mémoire. Dans la deuxième partie nous pousuivons ce travail en montrant comment exploiter la nature creuse des seconds membres pour réduire le volume de données accédées en mémoire. Dans la première partie de cette thèse nous introduisons deux approches de lecture des données sur le disque dur. Nous montrons ensuite que dans un environnement parallèle le séquencement des tâches peut fortement influencer la performance. Nous prouvons qu'un ordonnancement contraint des tâches peut être introduit; qu'il n'introduit pas d'interblocage entre processus et qu'il permet d'améliorer les performances. Nous conduisons nos expériences sur des problèmes industriels de grande taille (plus de 8 Millions d'inconnues) et utilisons une version hors-mémoire d'un code multifrontal creux appelé MUMPS (solveur multifrontal parallèle). Dans la deuxième partie de ce travail nous nous intéressons au cas de seconds membres creux multiples. Ce problème apparaît dans des applications en electromagnétisme et en assimilation de données et résulte du besoin de calculer l'espace propre d'une matrice fortement déficiente, du calcul d'éléments de l'inverse de la matrice associée aux équations normales pour les moindres carrés linéaires ou encore du traitement de matrices fortement réductibles en programmation linéaire. Nous décrivons un algorithme efficace de réduction du volume d'Entrées/Sorties sur le disque lors d'une résolution hors-mémoire. Plus généralement nous montrons comment le caractère creux des seconds -membres peut être exploité pour réduire le nombre d'opérations et le nombre d'accès à la mémoire lors de l'étape de résolution. Le travail présenté dans cette thèse a été partiellement financé par le projet SOLSTICE de l'ANR (ANR-06-CIS6-010). / We consider the solution of very large systems of linear equations with direct multifrontal methods. In this context the size of the factors is an important limitation for the use of sparse direct solvers. We will thus assume that the factors have been written on the local disks of our target multiprocessor machine during parallel factorization. Our main focus is the study and the design of efficient approaches for the forward and backward substitution phases after a sparse multifrontal factorization. These phases involve sparse triangular solution and have often been neglected in previous works on sparse direct factorization. In many applications, however, the time for the solution can be the main bottleneck for the performance. This thesis consists of two parts. The focus of the first part is on optimizing the out-of-core performance of the solution phase. The focus of the second part is to further improve the performance by exploiting the sparsity of the right-hand side vectors. In the first part, we describe and compare two approaches to access data from the hard disk. We then show that in a parallel environment the task scheduling can strongly influence the performance. We prove that a constraint ordering of the tasks is possible; it does not introduce any deadlock and it improves the performance. Experiments on large real test problems (more than 8 million unknowns) using an out-of-core version of a sparse multifrontal code called MUMPS (MUltifrontal Massively Parallel Solver) are used to analyse the behaviour of our algorithms. In the second part, we are interested in applications with sparse multiple right-hand sides, particularly those with single nonzero entries. The motivating applications arise in electromagnetism and data assimilation. In such applications, we need either to compute the null space of a highly rank deficient matrix or to compute entries in the inverse of a matrix associated with the normal equations of linear least-squares problems. We cast both of these problems as linear systems with multiple right-hand side vectors, each containing a single nonzero entry. We describe, implement and comment on efficient algorithms to reduce the input-output cost during an outof- core execution. We show how the sparsity of the right-hand side can be exploited to limit both the number of operations and the amount of data accessed. The work presented in this thesis has been partially supported by SOLSTICE ANR project (ANR-06-CIS6-010).

This research concentrates on the developing, implementing, and evaluating of a practical training program for the caregiver of an infant in order to provide in the infant’s primary needs and development. The research problem of quality care for the infant during the time that his mother is working was identified and discussed in chapter 1. Intervention research was used as research methodology. This methodology implies a combined quantitative and qualitative approach. The first part of this research (chapters 2&3) addresses the problem analysis and information gathering linked to the development of a theoretical basis for the intervention model. Infancy as developmental stage is discussed as well as the developmental tasks that the infant must achieve during this phase in order to grow and develop as a self-actualized individual (chapter 2). It is essential for the caregiver to gain knowledge and skills about infancy, the needs and the developmental tasks of this phase. The tasks, roles, and responsibilities of the caregiver were discussed in chapter 3. The second part of this research (chapter 4) is related to the design of the intervention program, the conducting of a pilot test and the refining of the intervention. This in-home care program is theoretically funded, and it is divided practically into the five workdays of the week, in accordance with the five developmental tasks that the infant must achieve in this developmental phase. Ten caregivers willingly participated in this intervention program. In chapter 5, the empirical findings with the development and implementation of the training program for in-home care of an infant are discussed. From the information gathered during the focus groups with the mothers of infants and caregivers as well as the results from the questionnaires from pre-tests and post-tests, the researcher came to the conclusion that the research problem of quality caretaking of an infant for the time his mother is working is addressed. Through internalizing theoretical knowledge and practical skills during the training program, the caregivers are able to care optimally for an infant at home. They are equipped with play techniques and mediums which are adapted within the gestalt approach and supported by relevant aids. The caregiver is able to stimulate the infant’s developmental needs and tasks in this developmental phase. Conclusions and recommendations (chapter 6) of this study are put forward in accordance with the process that was followed in developing and implementing the training program for optimal caretaking of the infant in the safe and familiar environment of his own home. / Thesis (DPhil (Social Work))--University of Pretoria, 2006. / Social Work and Criminology / Unrestricted

This study examines the impact of rapid and multi-faceted change (both domestically and inter-nationally over the past four decades) on the Dutch Reformed Church. 2 February 1990 is taken as a water shed date in the history of South-Africa: a speech in parliament of former president FW de Klerk put South-Africa on a course of fundamental change in all spheres of society. The research problem deals with loss the Afrikaans community experiences as a result of societal change. The result of change and loss is long-lasting, collective grief. Grief is defined as the nor-mal, spontaneous reaction to change and loss. Unresolved grief and nostalgia saps a lot of energy and tends to turn a congregation’s attention to itself, thereby contradicting the sound reformed ecclesiology. There is no appropriate practical theological theory to help congregations address unresolved grief. Change, loss and grief are made focus points for theological reflection and empirical study. The guiding hypothesis states that efforts to build up the local church are more likely to succeed, once the “black holes” of unaddressed grief have been dealt with by a collective and on-going process of mourning. Mourning is defined as an intentional and courageous process of letting go of different losses. It is hard work, but the result of deliberate mourning is growth – and eventually a more appropriate, new identity. Unresolved grief causes congregations to get stuck in survival mode, in stead of reaching out to the nations with the gospel of Jesus Christ. Mourning is an antidote (Hamman 2005:35). The research model of G Heitink (1993) is employed to generate fresh practical theological thinking on the research problem: that congregations fail to live according to their missional identity. The hermeneutical cycle explores the “new” practical theology in the framework of a post-Einstein epistemology, as well as the theory of building up the local church in the framework of an ecosystemic meta-theory. The hermeneutical cycle is concluded with the study of contemporary theories of loss, grief and mourning. The empirical cycle reports the results of a qualitative empirical study in three local congregations of the Northern Synod of the Dutch Reformed Church. A rich description is given of 31 respondents’ experience of loss and grief in the new South-Africa. It is established that unresolved grief indeed impacts negatively on efforts to build up the local church. The strategic cycle searches for practical theological wisdom and for a theory that can guide congregations to more productive responses to change and loss. The research boils down to twelve strategic suggestions for local congregations on how to make collective mourning a normal and on-going part of their ministry. The study concludes with the hypothesis that practical theology can serve the church by developing a theory that integrates intentional mourning and grief work as a necessary and normal aspect of ministry. / Thesis (PhD)--University of Pretoria, 2011. / Practical Theology / unrestricted

Throughout the world, including South Africa, various approaches have been identified and implemented in an attempt to ensure that employees in physically-demanding positions are properly managed from a physical work capacity point of view, the primary goal always being to return the employee in need of assistance to full working capacity as soon as possible. The burning question has, however, always remained: “What happens to the employee in the meantime?” This study focused on exactly that question, the aim being to develop a comprehensive tool to assist all parties concerned in managing the affected employee through the application of task-specific job accommodation. The predetermined goal of the study was to develop a task-specific job accommodation tool for a physically-demanding position. This was achieved through a number of steps, which included an extensive literature review, a thorough job analysis, identification of a suitable test battery with related minimum physical requirements and cut scores, interviews, and the eventual development of the tool. Once the task-specific job accommodation tool was completed, the next step was to make use of three case studies to assist in illustrating the way the tool is to be implemented, as well as to show the potential value of its implementation. The information from three actual incapacity cases in the company concerned was used for these case studies. The results from this study are extremely positive and the three case studies have provided a glimpse of the potential value that could be added through the implementation of the job accommodation tool. The final product will greatly assist the company concerned in managing incapacitated employees in a manner that is beneficial to both the company and the individuals involved. Hopefully, this study will contribute to bring about a new era in the way South African companies and their occupational health departments approach the management of their incapacitated employees. Copyright 2008, 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: Bester, GF 2008, A task-specific approach to job accommodation in physically-demanding positions, DPhil thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-10292008-180442 / > D498/gm / Thesis (DPhil)--University of Pretoria, 2008. / Biokinetics, Sport and Leisure Sciences / unrestricted

Mobile widgets now form a new paradigm of simplified web. Probably, the best experience of the Web is when a user has a widget for every frequently executed task, and can execute it anytime, anywhere on any device. However, the current method of programmatically creating personally relevant mobile widgets for every user does not scale. Creation of these mobile web widgets requires application programming as well as knowledge of web-related protocols. Furthermore, these mobile widgets are also limited to smart phones with data connectivity and such smart phones form just about 15% of the mobile phones in India. How do we make web accessible on devices that most people can afford? How does one create simple relevant tasks for the numerous diverse needs of every person? In this thesis, we attempt to address these issues and propose a new method of web simplification that enables an end-user to create simple single-click widgets for a complex personal task - without any programming. The proposed solution enables even low-end phones to access personal web tasks over SMS and voice. We propose a system that enables end users to create personal widgets via programming-by-browsing. A new concept called Tasklets to represent a user’s personal interaction, and a notion of programming over websites using a Web Virtual Machine are presented. Ensuring correct execution of these end user widgets posed interesting problems in web data mining and required us to investigate new methods to characterize and semantically model browser-based interactions. In particular, an instruction set for programming over web sites, new domain-specific similarity measures using ontologies, algorithms for frequent-pattern mining of web interactions and change detection with a proof of its NP-completeness are presented. A quantitative metric to measure the interaction complexity of web browsing and a method of classifying relational data using semantics hidden in the schema are introduced as well. This new web architecture to enable multi-device access to user's personal tasks over low-end phones was piloted with real users, as a solution named SiteOnMobile, and has received very positive response.

The work is focused on ECM and representation in the reference model of IT management MBI. The primary objective is to expand and update ECM components in the MBI as objects, tasks which are represented as the business processes related to IT management and the relationships between these objects and tasks. Work provides an detailed overview of the benefits, risks and problems associated with the implementation of the various components of ECM.

Les moyens et l'organisation de la justice sont des déterminants importants de l'efficacité de cette institution. Pourtant, ces aspects restent encore marginalement étudiés dans l'analyse économique du droit. Après avoir mis en évidence le besoin d'un cadre d'analyse économique des relations entre les résultats de l'activité judiciaire, les moyens alloués au système, la demande de justice et ses modes d'organisation, nous contribuons directement à l'exploration de ces relations. D'abord grâce à un modèle théorique, nous démontrons l'existence d'un effet multiplicateur des dépenses publiques de justice en nous appuyant sur l'analyse d'un type de conflits particulier : les conflits locatifs. Nous démontrons alors qu'une augmentation marginale des dépenses consacrées à la résolution de ce type de conflits améliore de manière significative à la fois le fonctionnement des tribunaux et le fonctionnement du marché du logement locatif. Ensuite, grâce à un test économétrique à partir de données originales – en particulier celles produites par la Commission Européenne pour l'Efficacité de la Justice – nous mettons en évidence un lien positif et robuste entre la confiance des individus dans la justice et diverses variables budgétaires. Nous développons l'idée que le budget de la justice joue un rôle de signal de la qualité de l'institution pour les agents dont la connaissance réelle du système judiciaire est limitée. Enfin, dans un modèle de double aléa moral appliqué à la production de justice, nous analysons les relations entre les moyens et l'organisation de la justice puis entre cette dernière et les résultats de son activité. Nous démontrons alors que certains équilibres du jeu stratégique entre les agents responsables de la production des services judiciaires – le gouvernement et les magistrats – correspondent à des situations inefficaces car les magistrats sont amenés à effectuer des tâches administratives à la place du gouvernement, au prix d'un niveau de production de services judiciaires relativement faible. / The means and organization of justice are important determinants of the efficiency of this institution. Nevertheless, these aspects still remain marginally studied in the economic analysis of law. After we have highlighted the need for an economic analytical framework of the relationships between the results of judicial activity, the means allocated to the system, the demand of justice and its organizational features, we directly contribute to the exploration of these relationships. First, thanks to a theoretical model, we demonstrate the existence of a multiplier effect of public expenditure on justice by focusing on the analysis of a particular type of disputes: rental ones. We thus demonstrate that a marginal increase in expenditures dedicated to the resolution of rental disputes significantly improves both the functioning of courts and the functioning of the rental market. Then, thanks to an econometrical test on original data – in particular the ones produced by the European Commission for the Efficiency of Justice – we show a positive and robust link between individuals' trust in justice and different budget-related variables. We argue that the justice budget plays a role as a signal of the institution's quality for agents whose knowledge about the reality of the judicial system is limited. Finally, using a double-sided moral hazard model applied to the production of justice, we analyze the relationship between the means and the organization of justice and then, between the organization and the results of judicial activity. We thus demonstrate that some of the equilibria of the strategic game between the agents who are responsible for the production of judicial services – the government and the magistrates – correspond to inefficient situations because magistrates are led to perform administrative tasks instead of the government, at the cost of a relatively low level of production of judicial services.

Significant associations between self-reported “whole units” of work and self-reported mental task requirements as well as personal outcomes are well known. Also of interest is, however, whether a significant association also exists between the underlying objective assignment of tasks, i.e. the division of labour, and self-reported mental requirements. Such an association would represent a concrete starting point for job design or redesign. We analyzed this question for retail sale jobs as an example of the numerous human service jobs, which usually consist of customer- and object-centred tasks. The study (N = 558 employees) evaluated the potential association between documented assignments of customer-centred and goods-centred activities and employees’ perceived mental requirements, skill utilisation, and learning on the job, as well as mental difficulties. A significant association of moderate effect size between the objective division of labour and self-reported mental job requirements was shown. Theoretical and practical consequences of this association are also discussed.

This Master´s thesis deals with the design of a robotic cell for manipulation operations. By two robots are performed manipulation operations with a product between turntable, station with a pulsed fiber laser, label printer with applicator and conveyor belt. Further, the thesis describes the selection process of each device of the robotic cell, the design of an end effector and a fixture. The robotic cell is designed in compliance with the safety standards. The aim of this thesis is to design the robotic cell, which meets the requirement for a given cycle time. The cycle time is determined using a simulation model of the robotic cell created in PLM software Siemens Process Simulate.

This master's thesis deals with design and implementation of modular system for two-way loudspeaker system's characteristics. Work focus mainly on the enclosure geometry and speaker placement. The individual modules of the system were designed and then implemented. Furthermore, the characteristics of these modules were measured and laboratory tasks using these modules were elaborated.