Le but de cette thèse est d'étudier et de développer des méthodes permettant de résoudre deux types de problèmes d'identification portant sur des équations elliptiques. Ces problèmes étant connus pour leur caractère fortement instable, les méthodes proposées s'accompagnent de procédures de régularisation, qui permettent d'assurer que la solution obtenue conserve un sens physique.Dans un premier temps, on étudie la résolution du problème de Cauchy (identification de conditions aux limites) par la méthode de Steklov-Poincaré. On commence par proposer quelques améliorations basées sur le solveur de Krylov utilisé, en introduisant notamment une méthode de régularisation consistant à tronquer la décomposition de Ritz de l'opérateur concerné. Par la suite, on s'intéresse à l'estimation d'incertitude en utilisant des techniques issues de l'inversion Bayésienne. Enfin, on cherche à résoudre des problèmes plus exigeants, à savoir un problème transitoire en temps, un cas non-linéaire, et on donne des éléments pour effectuer des résolutions sur des géométries ayant un très grand nombre de degrés de liberté en s'aidant de la décomposition de domaine.Pour ce qui est du problème d'identification de fissures par la méthode de l'écart à la réciprocité, on commence par proposer et tester numériquement différents moyens de stabiliser la résolution (utilisation de fonctions-tests différentes, minimisation des gradients a posteriori ou régularisation de Tikhonov). Puis on présente une autre variante de la méthode de l'écart à la réciprocité, qui est applicable aux cas pour lesquels les mesures sont incomplètes. Cette méthode, basée sur une approche de Petrov-Galerkine, est confrontée entre autres à un cas expérimental. Enfin, on s'intéresse à certaines idées permettant d'étendre la méthode de l'écart à la réciprocité à l'identification de fissures non planes. / The goal of this thesis is to study and to develop some methods in order to solve two types of identification problems in the framework of elliptical equations. As those problems are known to be particularly unstable, the proposed methods are accompanied with regularization procedures, that ensure that the obtained solutions keep a physical meaning.Firstly, we study the resolution of the Cauchy problem (boundary conditions identification) by the Steklov-Poincaré method. We start by proposing some improvements based on the used Krylov solver, especially by introducing a regularization method that consists in truncating the Ritz values decomposition of the operator in question. We study afterwards the estimation of uncertainties by the mean of techniques stemming from Bayesian inversion. Finally, we aim at solving more demanding problems, namely a time-transient problem, a non-linear case, and we give some elements to carry out resolutions on geometries that have a very high number of degrees of freedom, with help of domain decomposition.As for the problem of crack identification by the reciprocity gap method, we firstly propose and numerically test some ways to stabilize the resolution (use of different test-functions, a posteriori minimization of the gradients or Tikhonov regularization). Then we present an other variant of the reciprocity gap method, that is applicable on cases for which the measurements are incomplete. This method, based on a Petrov-Galerkin approach, is confronted, among others, with an experimental case. Finally, we investigate some ideas that allow to extend the reciprocity gap method for the identification of non-plane cracks.

This study seeks to explore anorexia nervosa as experienced within the South African coloured community in the specific. It represents an examination of themes within the participants’ depictions, discovering those themes that concur with existent literature, as well as discerning novel themes within the target group. Literature proves to yield varied results with regard to anorexia as presented in diverse cultures. Sufficient awareness is lacking within the South African context, where a scarcity of available literature that explores the experiences of the coloured anorexic individual necessitates the need for the current study. The contributing factors are viewed to involve societal, cultural, and familial aspects, all of which are situated within a systemic frame of reference. Systems theory provides the foundation within which these factors are explored, aiming to provide the reader with in-depth knowledge as to the functioning of the anorectic patient. It should be noted that these factors are interconnected, influencing each other in a circular manner. Attention is awarded to not only larger systems of societal and cultural influences, but also serves to encompass the functioning of the anorectic within the familial system. The reciprocity that exists within and between sub-systems is investigated, with the focus being the interrelatedness between members. Recursive feedback and associated processes are examined as they relate to the development and maintenance of anorexia. A qualitative research design was applied, where semi-structured interviews served as the chosen data collection strategy. Interviews were conducted at the hospital where they received treatment, and aimed to extract the meanings inherent in the participants’ experiences. A limited availability of diagnosed coloured anorexic individuals resulted in two willing participants partaking in the study. Thematic networks enabled the researcher to explore their representations in depth, leading to the subsequent organising of themes for further analysis. Two global themes emerged upon examination, the first of which was identified as “familial impact and patterns”, consisting of organising themes of relational positioning and interactional processes. Organising themes of expectations and internal emotional states constitute the second global theme of “control”. These themes are supported by a variety of basic themes, all of which serve to enhance the understanding of the organising themes, contributing to the respective global themes. Extensive exploration of the discovered themes followed, with the investigation proceeding within a systems theory framework. A conclusive discussion serves the purpose of bringing the exploration to a close. Relevant literature is incorporated into the discussion, providing the reader with an integrated understanding of the findings of the study within the broader field of anorexia nervosa. Copyright / Dissertation (MA)--University of Pretoria, 2008. / Psychology / unrestricted

Philosophiae Doctor - PhD / The value of accountability as a key feature of strengthening health systems and reducing maternal, newborn and child mortality is increasingly emphasised globally, nationally and locally. Frontline health professionals and managers play a crucial role in promoting maternal, newborn and child health (MNCH) services in an equitable and accountable manner. They are at the interface between higher-level health system management and communities, facing demands from both sides and often expected to perform beyond their available means. Although accountability is a central topic in the governance of MNCH literature, it has mostly been approached at global and national levels, with little understanding of how accountability is integrated into the routine functioning of local health systems. This PhD explores the forms and functioning of accountability at the district level focusing on MNCH as a programmatic area with long-established institutional mechanisms (structures and processes) in South Africa (SA). The thesis is presented in the form of four empirical papers (published or submitted), exploring different dimensions of accountability, which are embedded in a series of narrative chapters. In this thesis, accountability is understood as a set of relations between an accountholder and ‘accountor’ (or duty bearer), in which the latter provides information or justification for actions or decisions taken, and faces the resulting consequences of his/her actions (reward or sanction). Accountability mechanisms are the means to regulate accountability relationships and include broad strategies, interventions or instruments. These mechanisms can take various forms including performance, financial and public accountability, and operate both vertically (accountability inside bureaucratic hierarchies, or towards external stakeholders and/or the community), or horizontally (between peers, ‘neighbour’ units, departments or ministries in a national health system). Drawing conceptually on the field of governance and considering the complexity of the accountability phenomenon, I adopted a case study approach to the PhD research, using a combination of policy document review, interviews (with managers, providers, community representatives and members of labour unions) and field observations, conducted iteratively over 16 months. The study was conducted in Gert Sibande District, one of the three South African health districts in Mpumalanga Province, with an in-depth focus on two of the seven sub-districts in the District. The research found that frontline health professionals have a clear understanding and conceptualisation of accountability in the SA health policy context, despite the reported inability to define accountability by health professionals described in the literature. Respondents referred to accountability as responsibility, answerability and virtue, and also argued for strengthening accountability mechanisms as critical to addressing maternal and child mortality. While deeming accountability as important, frontline professionals experienced the existing accountability mechanisms as ‘too much’ and indicated the desire for the streamlining of existing mechanisms. In this regard, the study documented numerous mechanisms at district level, almost all related to performance accountability in MNCH. These included a performance management system, quality assessment and accreditation processes, quarterly reviews, and death surveillance and response processes. The existence of multiple and overlapping accountability mechanisms engenders operational confusion and ‘accountability overload’ for frontline providers, encouraging empty bureaucratic compliance, while critical gaps – notably in community accountability – remain. In practice, at their best, some mechanisms operate following a reciprocal1 pathway of capacity building with resource provision (from management) and expectation for better performance (from providers). There were, however, contextual variations in the implementation and practice of the mechanisms between sub-district settings. The fieldwork observations and interviews were also able to document how formal institutionalised mechanisms are embedded within a complex system of informal accountability relationships and social norms (‘accountability ecosystem’) that enables or constrains the ability of frontline professionals to fulfil their tasks. In addition, using a Social Network Analysis approach, the research identified key actors and their involved network, which form the relational backdrop to the functioning of accountability mechanisms for MNCH. By revealing complex relationships and collaboration patterns among frontline health professionals, the study was able to show the multi-level action and multiple actors required to achieve MNCH goals.

The diploma thesis Economic and social interaction during Normalization era is is based on qualitative research. It deals with issues of system of return services and barter exchange in non - cash market in 1970's and 1980's in Czechoslovakia. The centrally planned economy was not able to produce enough consumer goods and meet the demand of the population. Employees, who worked in department stores, took easier approach to consumer goods than others. They excercised power over distribution and they traded some commodities for another services. As a research method applied is oral history. The primary sources used are narrative interview and secondary history literature.

(in English) The subject of this thesis is the metamorphosis of intergenerational relationships within the family, which occur in the context of the social process of aging. The contemporary demographic trend has its deeper socio-economic context that currently the social policy of the state does not sufficiently reflect. It is necessary to perceive demographic aging as a metamorphosis of life cycle. The aim of this thesis is to present the proposition that the quality of intergenerational relationships is based on the entire life cycle of an individual, and therefore the reciprocity in the family can be influenced by appropriate measures of social policy. The aim of the thesis is (based on the available theoretical knowledge, using secondary data analysis and comparison of the data) to confirm the broader context of demographic aging and draw attention to the fact that in the preparation of social and political reform measures must deal with all relevant processes and not just the area of pension insurance.

How are people who generally see others positively evaluated themselves? We propose that the answer to this question crucially hinges on the content domain: We hypothesize that Agency follows a “zero-sum principle” and therefore people who see others as high in Agency are perceived as low in Agency themselves. In contrast, we hypothesize that Communion follows a “non-zero-sum principle” and therefore people who see others as high in Communion are perceived as high in Communion themselves. We tested these hypotheses in a round-robin and a half-block study. Perceiving others as agentic was indeed linked to being perceived as low in Agency. To the contrary, perceiving others as communal was linked to being perceived as high in Communion, but only when people directly interacted with each other. These results help to clarify the nature of Agency and Communion and offer explanations for divergent findings in the literature.

In electromechanical measurement techniques, passive transducers and passive electrical networks often interact. In some applications, continua are considered as part of the system, where fields are formed and waves are propagated. In this article, networks, continua, and electromechanical transducers feature sufficient amplitude linear behavior in their environment (e.g. for operation around a bias) and are reciprocal. In addition, all elements of the system have constant parameters during the measurement. Then, the skillful application of the inherent reciprocity of these systems can lead to surprisingly useful benefits. This is shown by actual examples from metrology. The examples include the precise determination of transduction coefficients. It is also shown how the linearity of a system is checked by utilizing reciprocityrelations. Although the facts of the matter are well known, its potential is often overlooked or disregarded in measurement techniques.

A question concerning not only modellers but also practitioners is: Under what circumstances can mutual cooperation be established and maintained by a group of people facing a common pool dilemma" A step before this question of institutional influences there is need for a different way of modelling human behaviour that does not draw on the rational actor paradigm, because this kind of modelling needs to be able to integrate various deviations from this theory shown in economic experiments. We have chosen a new approach based on observations in form of laboratory and field observations of actual human behaviour. We model human decision making as using an adaptive toolbox following the notion of Gigerenzer. Humans draw on a number of simple heuristics that are meaningful in a certain situation but may be useless in another. This is incorporated into our agent-based model by having agents perceive their environment, draw on a pool of heuristics to choose an appropriate one and use that heuristic.Behavioural differences can be incorporated in two ways. First, each agent has a number of attributes that differ in values, for example there are more and less cooperative agents. The second behavioural difference lies in the way, in which heuristics are chosen. With this modelling approach we contribute to a new way of modelling human behaviour, which is simple enough to be included into morecomplex models while at the same time realistic enough to cover actual decision making processes of humans. Modellers should be able to use this approach without a need to get deep into psychological, sociological or economic theory. Stakeholders in social dilemmas, who may be confronted with such a model should understand, why an agent decides in the way it does.

Generational conflicts affect socialization practices needed for knowledge transfer and Millennial retention. Because of failed socialization practices, organizations will face significant losses in knowledge capital as Boomers retire and Millennials began to take active roles within the workplace. This interpretative phenomenological study explored Millennials' perceptions of leader-to-employee relationship development that may influence organizational learning and retention practices. Millennial retention is a primary concern in that knowledge acquired is a result of longevity and work experience. The leader-to-member exchange theory was used to navigate this qualitative inquiry. The reflexive approach was implemented to explore 20 Millennial participants' experiences with their managers. The data analysis strategy incorporated a repetitious review and structural coding of participant interview transcripts. Data analysis affirmed that Millennials perceive effective relationship development as a process containing leader empowerment behaviors with collaborative social exchanges. Exploration of participant experiences further identified that reciprocity is a result of high-quality social exchanges. Research findings benefit executive and middle-level management. The information broadens management knowledge of Millennials' perceptions of relationship development that may increase employee retention needed for robust social systems. The implications for positive social change are that increased awareness of advanced relational leadership systems assists in building congruent internal relationships required for organizational learning and retention.

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