Im Buch werden verschiedene Ansätze zum induktiven Schließen vorgestellt und daraufhin analysiert, welche Erfolgsaussichten sie jeweils bieten, die erkenntnistheoretischen Ziele der Wissenschaften zu erreichen. Dabei werden u.a. die konsverativen Induktionsschlüsse, Falsifikationsverfahren und die eliminative Induktion, der Schluss auf die beste Erklärung und vor allem der Bayesianismus besprochen. Außerdem geht es um die Verfahren der klassischen Statistik sowie moderne Verfahren des kausalen Schließens. Dazu wird ein erkenntnistheoretischer Rahmen angegeben, in dem die verschiedenen Begründungsverfahren untereinander verglichen werden.

Abnormal electromagnetic wave propagation characterized by negative group velocity and consequently negative group delay (NGD) has been observed in certain materials as well as in artificially built structures. Within finite frequency intervals where an NGD phenomenon is observed, higher frequency components of the applied waveform are propagated with phase advancement, not delay, relative to the lower frequency components. These media have found use in many applications that require positive delay compensation and an engineered phase characteristic, such as eliminating phase variation with frequency in phase shifters, beam-squint minimization in phased array antenna systems, size reduction of feed-forward amplifiers and others. The three principal questions this thesis addresses are: can a generic formulation for artificial NGD structures based on electric circuit resonators be developed; is it possible to derive a quantitative functional relationship (asymptotic limit) between the maximum achievable NGD and the identified trade-off quantity (out-of-band gain); and, can a microwave circuit exhibiting a fully loss-compensated NGD propagation in both directions be designed and implemented? A generic frequency-domain formulation of artificial NGD structures based on electric circuit resonators is developed and characterized by three parameters, namely center frequency, bandwidth and the out-of-band gain. The developed formulation is validated through several topologies reported in the literature. The trade-off relationship between the achievable NGD on one hand, and the out-of-band gain on the other, is identified. The out-of-band gain is shown to be proportional to transient amplitudes when waveforms with defined “turn on/off” times are propagated through an NGD medium. An asymptotic limit for achievable NGD as a function of the out-of-band gain is derived for multi-stage resonator-based NGD circuits as well as for an optimally engineered linear causal NGD medium. Passive NGD media exhibit loss which can be compensated for via active elements. However, active elements are unilateral in nature and therefore do not allow propagation in both directions. A bilateral gain-compensated circuit is designed and implemented, which overcomes this problem by employing a dual-amplifier configuration while preserving the overall circuit stability.

Abnormal electromagnetic wave propagation characterized by negative group velocity and consequently negative group delay (NGD) has been observed in certain materials as well as in artificially built structures. Within finite frequency intervals where an NGD phenomenon is observed, higher frequency components of the applied waveform are propagated with phase advancement, not delay, relative to the lower frequency components. These media have found use in many applications that require positive delay compensation and an engineered phase characteristic, such as eliminating phase variation with frequency in phase shifters, beam-squint minimization in phased array antenna systems, size reduction of feed-forward amplifiers and others. The three principal questions this thesis addresses are: can a generic formulation for artificial NGD structures based on electric circuit resonators be developed; is it possible to derive a quantitative functional relationship (asymptotic limit) between the maximum achievable NGD and the identified trade-off quantity (out-of-band gain); and, can a microwave circuit exhibiting a fully loss-compensated NGD propagation in both directions be designed and implemented? A generic frequency-domain formulation of artificial NGD structures based on electric circuit resonators is developed and characterized by three parameters, namely center frequency, bandwidth and the out-of-band gain. The developed formulation is validated through several topologies reported in the literature. The trade-off relationship between the achievable NGD on one hand, and the out-of-band gain on the other, is identified. The out-of-band gain is shown to be proportional to transient amplitudes when waveforms with defined “turn on/off” times are propagated through an NGD medium. An asymptotic limit for achievable NGD as a function of the out-of-band gain is derived for multi-stage resonator-based NGD circuits as well as for an optimally engineered linear causal NGD medium. Passive NGD media exhibit loss which can be compensated for via active elements. However, active elements are unilateral in nature and therefore do not allow propagation in both directions. A bilateral gain-compensated circuit is designed and implemented, which overcomes this problem by employing a dual-amplifier configuration while preserving the overall circuit stability.

Algebraic Quantum Field Theory (AQFT) is a mathematically rigorous framework that was developed to model the interaction of quantum mechanics and relativity. In AQFT, quantum mechanics is modelled by C*-algebras of observables and relativity is usually modelled in Minkowski space. In this thesis we will consider a generalization of AQFT which was inspired by the work of Abramsky and Coecke on abstract quantum mechanics [1, 2]. In their work, Abramsky and Coecke develop a categorical framework that captures many of the essential features of finite-dimensional quantum mechanics. In our setting we develop a categorified version of AQFT, which we call premonoidal C*-quantum field theory, and in the process we establish many analogues of classical results from AQFT. Along the way we also exhibit a number of new concepts, such as a von Neumann category, and prove several properties they possess. We also establish some results that could lead to proving a premonoidal version of the classical Doplicher-Roberts theorem, and conjecture a possible solution to constructing a fibre-functor. Lastly we look at two variations on AQFT in which a causal order on double cones in Minkowski space is considered.

The aim of this study is to explore ways to maximise the economic returns of road infrastructure investment. In order to achieve this objective, the study was divided into five parts involving the following: analysing the nature of road infrastructure, determining the relationship between road infrastructure investment and economic development, considering aspects of economic modelling, developing a formula of road investment, and refocusing road investment practices. In the first part the characteristics of road infrastructure are examined and the demand and supply approaches to road investment outlined. The focus is on the balanced approach versus the unbalanced approach to infrastructure investment. The second part analyses the causal relationship between road investment and economic development. Four components are highlighted, namely the investment component, the network-performance component, the transport economic component and the economic development component. The third part analyses the applicability of modelling techniques. In the fifth part, the formula of road investment and economic development is focused on four markets. Finally, it is argued that road infrastructure investment must be refocused. The following was found: Road infrastructure investment must be demand led. This is because of the characteristics of roads, namely their indivisibility, long gestation period, lumpiness and high cost. Road infrastructure investment can only realise economic development if the four causality components are complied with simultaneously. Input-output modelling is preferred in South Africa. The modelling strategy developed in this study is recommended for transport economic studies. The probability of economic returns of road infrastructure investment is a function of the real estate market, the land development market, the urban economic market and the infrastructure market. An agenda for reform in the road investment industry was also proposed. The study clearly identifies the relationship between road infrastructure investment and economic development, and the proposed formula is an appropriate tool for a first-order priority system. / Transport Economics, Logistics and Tourism / D. Com. (Transport Economics)

Parental monitoring of settings is not always relevant for the prevention of adolescent crime because adolescents with strong personal moral rules and the ability to exercise self control are unlikely to offend even when they are unsupervised and know that their parents have little knowledge about their activities. Parental monitoring, commonly operationalised as parental supervision or parental knowledge, is often shown to have a negative relationship with crime involvement. However, research often ignores both the mechanism by which these relationships occur and the conditions under which they might (and might not) be found. This thesis uses specialist Space-Time Budget data (from the Peterborough Adolescent and Young Adult Development Study) to allow the comparison of adolescent crime rates in settings characterised by the of convergence of i) the physical presence or absence of parents and other guardians, ii) the psychological presence or absence of parents (represented by adolescent-perceived generalised parental knowledge of the circumstances of unsupervised activity) and iii) personal crime propensity (moral rules and ability to exercise self control). The conclusion derived from the results is that the physical presence of parents and other guardians in settings reduces the rate of adolescent crime committed in those settings; and the psychological presence of parents reduces the criminogenic impact of unsupervised time. Crucially however, these effects of parental monitoring are almost irrelevant for adolescents with a lower personal crime propensity, who are not likely to offend in settings irrespective of the physical or psychological absence of parents and other guardians. These findings provide support for person-environment interactions inherent in the causal model of Situational Action Theory, and provide a novel addition to evidence that could be used in future to inform policy-relevant recommendations concerning parenting behaviour and adolescent offending. Although this thesis provides new evidence about the relationship between parental monitoring and crime, the bulk of its contribution is relevant to a much wider audience. It contributes to the debate on approaches to the study of crime and crime prevention, adds clarity to key concepts and develops theoretical arguments in the field of parental monitoring and crime, develops a novel application of Situational Action Theory, extends theoretical and methodological discussions surrounding situational analysis, applies novel data and analytical methods to the study of the psychological and physical presence of guardians, generates and situates unique findings about the situational role of aspects of parental monitoring and crime, and makes some policy recommendations and suggestions about the nature and direction of future research.

The aim of the thesis is to examine both Husserl's and Kant's transcendentalism in a way that would avoid the tendency to put the main accent on Husserl, which is an approach common to almost all literature dealing with this topic so far. Since it is for the most part Husserl's own critique of Kant that inspires such ongoing underestimation of Kant in comparison to Husserl, this work focuss on the question of the legitimacy of this critique. The core of the thesis is an original interpretation of Kant's transcendental philosophy which, instead of taking for granted the phenomenological point of view, attempts to describe Kant's philosophical enterprise from its own perspective and in its own right. In its second part, the thesis provides a brief description of how Husserl, starting initially from the position of descriptive psychology, arrives at a transcendental dimension. When so put side by side, it becomes evident that the two transcendental positions are in fact very different. Husserl's critique of Kant then appears as unjustified, even though quite understandable as an attempt to draw back from certain immature motives of his own philosophy.

Financial liberalisation, through increasing investment as well as the average productivity of capital, should stimulate economic growth, or so the theory goes. Bank lending unfortunately suffers adverse selection and moral hazard effects, to which the establishment and expansion of stock markets has been offered as a remedy. However, research from developing country stock markets have shown that in many cases these markets did not complement the effects of credit market liberalisation but in rather important aspects subverted them. Countries that implemented credit market liberalisation and raised real interest rates only increased the price of debt capital rather than all capital. This caused a share price boom in many of them. When the price of equity capital fell it seriously undermined and indeed allowed large private corporations to skip altogether the main channel of high interest rates through which the theoretical McKinnon-Shaw effects were to operate. This study asks the research question of what effect the expansion of the South African stock exchange has had for its economic development. It makes use of a general empirical model to explain the relationship between financial development and real output. The model comprises indicators for growth, banking system development, stock market volatility; and, stock market development through a conglomerate index that accounts for market size, liquidity and integration with world capital markets. Quarterly data from 1989 to 2001 is analysed based on the null hypothesis that, as far as financial architecture is concerned, the development of the JSE Securities Exchange has stimulated the country's economic growth. This study found a negative and statistically significant relation between stock market development and economic growth. It suggests that while the JSE Securities Exchange is a relatively large stock market it is the presence of thin trading that prevents the proposed benefits of market development from accruing to the economy. Thus the hypothesis is rejected. However, since the only stable cointegrating vector is between growth and banking sector development, it recommends that by expanding their universal banking functions, the present banking structure, though oligopolistic, may be better suited to act as a catalyst for growth. / Business Management / D. Comm.

L’étude que nous avons consacrée à la Antología poética 1923-1977 permet de mettre en lumière l’art poétique de Jorge Luis Borges ainsi que d’observer attentivement la dimension spéculaire et la portée universelle de sa poésie. Elle condense, reflète, et nous fait appréhender l’essence du monde dans toute la gamme de ses infinies richesses ainsi que de ses insondables mystères qui hantent la réflexion métaphysique de l’humanité depuis des temps immémoriaux. Nous dégageons, tout particulièrement, nombre de convergences des plus frappantes entre les principaux thèmes borgésiens et les thèses majeures du philosophe Arthur Schopenhauer. Borges emploie, à l’évidence, tout son génie, tout son art de la perplexité et de l’ironie, à façonner subtilement un miroir poétique de la pensée de ce grand maître qu’il vénère tant. Nous constatons, en effet, que la poésie borgésienne, non seulement nous fait prendre conscience de notre perpétuelle et irrémédiable condamnation aux illusions et aux représentations, mais encore tente de relever le défi du dépassement des illusions, d’un accès à un au-delà de la représentation. Sous de multiples aspects kaléidoscopiques de l’Autre (un sablier, un jardin, une bibliothèque, un château, un rêve, la pensée humaine, l’individu, l’écriture, le temps…), c’est en réalité toujours le mythe de l’Eternel Retour du Labyrinthe qui revient sous sa plume. Comment ce mythe ― à la fois personnel et impersonnel ― que Borges a patiemment forgé, tout au long de sa vie, a-t-il pu connaître une remarquable diffusion planétaire et le conduire à être couronné par la gloire de son vivant ? Telle est l’ultime question à laquelle nous tâchons de répondre au terme de notre réflexion. / The study that we dedicated to the Antología Poética 1923-1977 allows to bring out the poetical art of Jorge Luis Borges as well as to observe in a careful way the speculiar dimension and the universal scope of his poetry. It condenses, reflects and enables us to apprehend the essence of the world in the whole range of infinite riches, as well as the unfathomable mysteries which have haunted the metaphysical reflexion of humanity from time immemorial. We bring out, in particular, a fair number of the most striking convergences between the main themes of Borges the poet and the major thesis of Arthur Schopenhauer the philosopher. It is obvious that Borges uses all his genius, all his art of perplexity and irony to shape, in a subtle way, a poetical mirror of the thinking of this great master that he venerates so much. Not only do we notice that the poetry of Borges enables us to be aware of our perpetual and irreparable condemnation to illusions and representations, but it also tries to take up the challenge of surpassing the illusions, of an access to the beyond of representation. Under numerous kaleidoscopic aspects of the Other (a sandglass, a garden, a library, a castle, a dream, the human thought, the individual, writing, time…), in fact it is always the myth of the Eternal Return of the Labyrinth which comes back under his pen. How can this myth – both personal and impersonal – (patiently forged by Borges all along his life) have met such a remarkable worldwide diffusion and have led him to be crowned by glory in his lifetime? This is the final question we will try to carry through.

Les TIC sont un facteur clé de performance dans les pays développés. Cette thèse s’intéresse à l’adoption des TIC et leur impact sur la performance des PME manufacturières d’un pays en développement. A la suite d’une première partie qui présente le cadre théorique et conceptuel, le reste de la thèse est organisé en trois études empiriques. La première étude propose une modélisation Probit afin d’identifier les déterminants d’adoption des TIC. Le capital humain est la variable explicative la plus significative. Se basant sur la régression linéaire à variables muettes, la causalité de Granger, le test de Kruskal-Wallis et le test de l’ANOVA de Welch, suivis des tests post-hoc correspondants, la deuxième étude met en évidence l’existence d’un fort lien statistique significatif entre le niveau d’adoption des TIC et la rentabilité. Dans une troisième étude, plusieurs modélisations Probit (simple, ordonné et multivarié) ont été testées sur différentes mesures de performance. Nous montrons, premièrement, que les TIC ont un impact positif sur la productivité, la rentabilité et la compétitivité. Deuxièmement, les TIC, le capital humain et la formation sont les déterminants de la performance globale. Enfin, la contribution des TIC à la performance globale est forte lorsqu’elles sont combinées au capital humain qualifié. En définitive, nos résultats empiriques ont montré un effet positif des TIC, du capital humain et du changement organisationnel sur la performance des PME. / ICT is a key performance factor in developed countries. This PhD thesis focuses on the adoption of ICTs and their impact on the performance of manufacturing SMEs in a developing country. Following a first part covering the theoretical and conceptual framework, the rest of the thesis is organized in three empirical studies. The first study uses a Probit model in order to identify the determinants of ICT adoption. Human capital seems to be the most significant explanatory variable. Based on linear regression of dummy variables, Granger causality, Kruskal-Wallis test, ANOVA test of Welch, followed by corresponding post-hoc tests, the second study highlights the existence of a strong statistically significant relationship between the level of ICT adoption and profitability. In a third study, many Probit models (simple, ordered and multivariate) were tested on different measures of performance. Firstly, we show that ICT have a positive impact on productivity, profitability and competitiveness of SMEs. Secondly, ICT, human capital and training are determinants of firm overall performance. Thirdly, when combined together, ICT and highly skilled human resources have an important contribution to the global performance. In conclusion, our empirical results demonstrate a positive impact of ICT, human capital and organizational change on firm performance.