Cette thèse a pour but l'enrichissement des méthodes supervisées d'analyse de données symboliques et l'extension de ce domaine aux données volumineuses, dites "Big Data". Nous proposons à cette fin une méthode supervisée nommée HistSyr. HistSyr convertit automatiquement les variables continues en histogrammes les plus discriminants pour les classes d'individus. Nous proposons également une nouvelle méthode d'arbres de décision symbolique, dite SyrTree. SyrTree accepte tous plusieurs types de variables explicatives et à expliquer pour construire l'arbre de décision symbolique. Enfin, nous étendons HistSyr aux Big Data, en définissant une méthode distribuée nommée CloudHistSyr. CloudHistSyr utilise Map/Reduce pour créer les histogrammes les plus discriminants pour des données trop volumineuses pour HistSyr. Nous avons testé CloudHistSyr sur Amazon Web Services (AWS). Nous démontrons la scalabilité et l’efficacité de notre méthode sur des données simulées et sur les données expérimentales. Nous concluons sur l’utilité de CloudHistSyr qui , grâce à ses résultats, permet l'étude de données massives en utilisant les méthodes d'analyse symboliques existantes. / This Thesis proposes new supervised methods for Symbolic Data Analysis (SDA) and extends this domain to Big Data. We start by creating a supervised method called HistSyr that converts automatically continuous variables to the most discriminant histograms for classes of individuals. We also propose a new method of symbolic decision trees that we call SyrTree. SyrTree accepts many types of inputs and target variables and can use all symbolic variables describing the target to construct the decision tree. Finally, we extend HistSyr to Big Data, by creating a distributed method called CloudHistSyr. Using the Map/Reduce framework, CloudHistSyr creates of the most discriminant histograms for data too big for HistSyr. We tested CloudHistSyr on Amazon Web Services. We show the efficiency of our method on simulated data and on actual car traffic data in Nantes. We conclude on overall utility of CloudHistSyr which, through its results, allows the study of massive data using existing symbolic analysis methods.

<p>Language “in the wild” is complex and ambiguous and relies on a shared understanding of the world for its interpretation. Most current natural language processing methods represent language by learning word co-occurrence patterns from massive amounts of linguistic data. This representation can be very powerful, but it is insufficient to capture the meaning behind written and spoken communication. </p> <p> </p> <p>In this dissertation, I will motivate neural-symbolic representations for dealing with these challenges. On the one hand, symbols have inherent explanatory power, and they can help us express contextual knowledge and enforce consistency across different decisions. On the other hand, neural networks allow us to learn expressive distributed representations and make sense of large amounts of linguistic data. I will introduce a holistic framework that covers all stages of the neural-symbolic pipeline: modeling, learning, inference, and its application for diverse discourse scenarios, such as analyzing online discussions, mining argumentative structures, and understanding public discourse at scale. I will show the advantages of neural-symbolic representations with respect to end-to-end neural approaches and traditional statistical relational learning methods.</p> <p><br></p> <p>In addition to this, I will demonstrate the advantages of neural-symbolic representations for learning in low-supervision settings, as well as their capabilities to decompose and explain high-level decision. Lastly, I will explore interactive protocols to help human experts in making sense of large repositories of textual data, and leverage neural-symbolic representations as the interface to inject expert human knowledge in the process of partitioning, classifying and organizing large language resources. </p>

No description available.

Considered as the ―...central organizing method‖ (Fuss, 1991:1) in terms of gender and sexual orientation particularly in the Western world, the heterosexual/homosexual binary, emphasises the centrality of ―compulsory heterosexuality‖ (Rich, 1993:227) in the everyday lives of social and sexual actors. In doing this, homosexuality is not only differentiated from heterosexuality, but may rather be ‗banished‘ to a lower and subordinate stratum of so-called sexual ―respectability‖ (Rubin, 1993:13). Using it as a point of departure, this particular sociological inquiry sought to critically explore the influence of a binary logic on the identity construction of gay male academics and students in South African tertiary education. This study provides an in-depth qualitative discussion of the lived experiences of these men on university campuses in order to redress the limited focus on the subject matter in South African sociology. Informed by the metatheoretical principles of phenomenology and central features of a symbolic interactionist methodology, three specific subthemes guided the research. These included the rationalisation of sexual orientation, self-reflexivity and, as my inductive contribution, a consideration of the deprofessionalisation and/or professionalisation of the gay male academic identity in South African higher education. In adopting Jackson and Scott‘s (2010) conceptualisation of the rationalisation of sexuality, the study sought to explore its role in the identity construction of gay men through, amongst others, ―sexual scripting‖ (Gagnon & Simon, 1973), ―doing gender‖ (West & Zimmerman, 2002), ―using gender‖ (Johnson, 2009) as well as ―doing gay‖ (Dowsett et al., 2008), to (de)construct a ―gay sensibility‖ (cf. Seidman, 2002a) within and between their private and professional contexts. Secondly, such negotiation of their homosexual ―performativity‖ (Butler, 1990) presupposed an undeniable degree of ―reflexiveness‖ (cf. Mead, 1962) on the part of the gay male, to adhere to the expectations of other individuals in a specific social context. Given the findings from a thematic analysis of fifteen (15) in-depth interviews with academics and seven (7) with students, as well as two (2) self-administered questionnaires completed by academics and seventeen (17) by students, the influence of heteronormativity, heterosexism and homophobia, was again reiterated. The participants mostly opted to professionalise their gay male identities (thus differentiate between their private and academic gay male identity), regardless of the fact that their narratives reflected an internal diversity, plurality and potentially non-subordinate otherness, akin to Plummer‘s (1998b) reference to ―homosexualities‖ rather than only one homogenised version of ‗homosexuality‘. Their choice to do so was attributed to a conscious effort to either ‗pass‘ as heterosexual, assimilate into the dominant sexual and gendered culture of the campus, or conform to a stereotypical gay performance in homosexually-segregated academic departments because of anxiety, fear or shame. As such, the potential of mastering an uncategorised ‗queer‘ inclination in tertiary education, becomes all the more difficult, if not improbable. / PhD (Sociology), North-West University, Potchefstroom Campus, 2014

Considered as the ―...central organizing method‖ (Fuss, 1991:1) in terms of gender and sexual orientation particularly in the Western world, the heterosexual/homosexual binary, emphasises the centrality of ―compulsory heterosexuality‖ (Rich, 1993:227) in the everyday lives of social and sexual actors. In doing this, homosexuality is not only differentiated from heterosexuality, but may rather be ‗banished‘ to a lower and subordinate stratum of so-called sexual ―respectability‖ (Rubin, 1993:13). Using it as a point of departure, this particular sociological inquiry sought to critically explore the influence of a binary logic on the identity construction of gay male academics and students in South African tertiary education. This study provides an in-depth qualitative discussion of the lived experiences of these men on university campuses in order to redress the limited focus on the subject matter in South African sociology. Informed by the metatheoretical principles of phenomenology and central features of a symbolic interactionist methodology, three specific subthemes guided the research. These included the rationalisation of sexual orientation, self-reflexivity and, as my inductive contribution, a consideration of the deprofessionalisation and/or professionalisation of the gay male academic identity in South African higher education. In adopting Jackson and Scott‘s (2010) conceptualisation of the rationalisation of sexuality, the study sought to explore its role in the identity construction of gay men through, amongst others, ―sexual scripting‖ (Gagnon & Simon, 1973), ―doing gender‖ (West & Zimmerman, 2002), ―using gender‖ (Johnson, 2009) as well as ―doing gay‖ (Dowsett et al., 2008), to (de)construct a ―gay sensibility‖ (cf. Seidman, 2002a) within and between their private and professional contexts. Secondly, such negotiation of their homosexual ―performativity‖ (Butler, 1990) presupposed an undeniable degree of ―reflexiveness‖ (cf. Mead, 1962) on the part of the gay male, to adhere to the expectations of other individuals in a specific social context. Given the findings from a thematic analysis of fifteen (15) in-depth interviews with academics and seven (7) with students, as well as two (2) self-administered questionnaires completed by academics and seventeen (17) by students, the influence of heteronormativity, heterosexism and homophobia, was again reiterated. The participants mostly opted to professionalise their gay male identities (thus differentiate between their private and academic gay male identity), regardless of the fact that their narratives reflected an internal diversity, plurality and potentially non-subordinate otherness, akin to Plummer‘s (1998b) reference to ―homosexualities‖ rather than only one homogenised version of ‗homosexuality‘. Their choice to do so was attributed to a conscious effort to either ‗pass‘ as heterosexual, assimilate into the dominant sexual and gendered culture of the campus, or conform to a stereotypical gay performance in homosexually-segregated academic departments because of anxiety, fear or shame. As such, the potential of mastering an uncategorised ‗queer‘ inclination in tertiary education, becomes all the more difficult, if not improbable. / PhD (Sociology), North-West University, Potchefstroom Campus, 2014

Text in Afrikaans, abstract in Afrikaans and English / Die gebruik van simbole maak wiskunde eenvoudiger en kragtiger, maar ook moeiliker verstaanbaar. Laasgenoemde kan voorkom word as slegs eenvoudige en noodsaaklike simbole gebruik word, met die verduidelikings en motiverings in woorde. Die krag van simbole le veral in die feit dat simbole as substitute vir konsepte kan dien. Omdat die krag van simbole hierin le, skuil daar 'n groot gevaar in die gebruik van simbole. Wanneer simbole los is van sinvolle verstandsvoorstellings, is daar geen krag in simbole nie. Dit is die geval met die huidige benadering in skoolalgebra. Voordat voldoende verstandsvoorstellings opgebou is, word daar op die manipulasie van simbole gekonsentreer. Die algebraiese historiese-kenteoretiese perspektief maak algebra meer betekenisvol vir leerders. Hiervolgens moet die leerlinge die geleentheid gegun word om oplossings in prosavorm te skryf en self hul eie wiskundige simbole vir idees spontaan in te voer. Hulle moet self die voordeel van algebraiese simbole beleef. / The use of symbols in algebra both simplifies and strengthens the subject, but it also increases its level of complexity.This problem can be prevented if only simple and essential symbols are used and if the explanations are fully verbalised. The power of symbols stems from their potential to be used as substitutes for concepts. As this constitutes the crux of mathematical symbolic representation, it also presents a danger in that the symbols may not be comprehended. If symbols are not related to mental representations, the symbols are meaningless. This is the case in the present approach to algebra. Before sufficient mental representations are built, there is a concentration on the manipulation of symbols. The algebraic historical epistemological perspective makes algebra more meaningful for learners. Learners should be granted the opportunities to write their solutions in prose and to develop their own symbols for concepts. / Mathematics Education / M. Sc. (Wiskunde-Onderwys)

We show how the non-monotonic nature of common-sense reasoning can be formalised by circumscription. Various forms of circumscription are discussed. A new form of circumscription, namely naive circumscription, is introduced in order to facilitate the comparison of the various forms. Finally, some issues connected with the automation of circumscriptive reasoning are examined. / Computing / M. Sc. (Computer Science)

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Symbolic execution is a well-established technique for automated test generation and for nding errors in complex code. Most of the focus has however been on programs that manipulate integers, booleans, and even, references in object-oriented programs. Recently researchers have started looking at programs that do lots of string processing, motivated, in part, by the popularity of the web and the risk that errors in web servers may lead to security violations. Attempts to extend symbolic execution to the domain of strings are mainly divided into one of two camps: automata-based approaches and approaches based on bitvector analysis. Here we investigate these two approaches in a uni ed setting, namely the symbolic execution framework of Java PathFinder. We describe the implementations of both approaches and then do an evaluation to show under what circumstances each approach performs well (or not so well). We also illustrate the usefulness of the symbolic execution of strings by nding errors in real-world examples. / AFRIKAANSE OPSOMMING: Simboliese uitvoering is 'n bekende tegniek vir automatiese genereering van toetse en om foute te vind in ingewikkelde bronkode. Die fokus sover was grotendeels op programme wat gebruik maak van heelgetalle, boolse waardes en selfs verwysings in objek geörienteerde programme. Navorsers het onlangs begin kyk na programme wat baie gebruik maak van string prosessering, deelteliks gemotiveerd deur die populariteit van die web en die gepaardgaande risiko's daarvan. Vorige implementasies van simboliese string uitvoering word binne twee kampe verdeel: die automata gebaseerde benadering en bitvektoor gebaseerde benadering. Binne hierdie tesis word die twee benaderings onder een dak gebring, naamliks Java PathFinder. Die implentasie van beide benaderings word bespreek en ge-evalueer om die omstandighede uit te wys waarbinne elk beter sou vaar. Die nut van simboliese string uitvoering word geïllustreer deur dit toe te pas in foutiewe regte wêreld voorbeelde.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Probabilistic symbolic execution is a new approach that extends the normal symbolic execution with probability calculations. This approach combines symbolic execution and model counting to estimate the number of input values that would satisfy a given path condition, and thus is able to calculate the execution probability of a path. The focus has been on programs that manipulate primitive types such as linear integer arithmetic in object-oriented programming languages such as Java. In this thesis, we extend probabilistic symbolic execution to handle data structures, thus allowing support for reference types. Two techniques are proposed to calculate the probability of an execution when the programs have structures as inputs: an approximate approach that assumes probabilities for certain choices stay fixed during the execution and an accurate technique based on counting valid structures. We evaluate these approaches on an example of a Binary Search Tree and compare it to the classic approach which only take symbolic values as input. / AFRIKAANSE OPSOMMING: Probabilistiese simboliese uitvoering is ’n nuwe benadering wat die normale simboliese uitvoering uitbrei deur waarksynlikheidsberekeninge by te voeg. Hierdie benadering kombineer simboliese uitvoering en modeltellings om die aantal invoerwaardes wat ’n gegewe padvoorwaarde sal bevredig, te beraam en is dus in staat om die uitvoeringswaarskynlikheid van ’n pad te bereken. Tot dus vêr was die fokus op programme wat primitiewe datatipes manipuleer, byvoorbeeld lineêre heelgetalrekenkunde in objek-geörienteerde tale soos Java. In hierdie tesis brei ons probabilistiese simboliese uitvoering uit om datastrukture, en dus verwysingstipes, te dek. Twee tegnieke word voorgestel om die uitvoeringswaarskynlikheid van ’n program met datastrukture as invoer te bereken. Eerstens is daar die benaderingstegniek wat aanneem dat waarskynlikhede vir sekere keuses onveranderd sal bly tydens die uitvoering van die program. Tweedens is daar die akkurate tegniek wat gebaseer is op die telling van geldige datastrukture. Ons evalueer hierdie benaderings op ’n voorbeeld van ’n binêre soekboom en vergelyk dit met die klassieke tegniek wat slegs simboliese waardes as invoer neem.

Cette thèse est consacrée à l'étude des différents problèmes liés aux structures des cubes , en théorie ergodique et en dynamique topologique. Elle est composée de six chapitres. La présentation générale nous permet de présenter certains résultats généraux en théorie ergodique et dynamique topologique. Ces résultats, qui sont associés d'une certaine façon aux structures des cubes, sont la motivation principale de cette thèse. Nous commençons par les structures de cube introduites en théorie ergodique par Host et Kra (2005) pour prouver la convergence dans $L^2 $ de moyennes ergodiques multiples. Ensuite, nous présentons la notion correspondante en dynamique topologique. Cette théorie, développée par Host, Kra et Maass (2010), offre des outils pour comprendre la structure topologique des systèmes dynamiques topologiques. En dernier lieu, nous présentons les principales implications et extensions dérivées de l'étude de ces structures. Ceci nous permet de motiver les nouveaux objets introduits dans la présente thèse, afin d'expliquer l'objet de notre contribution. Dans le Chapitre 1, nous nous attachons au contexte général en théorie ergodique et dynamique topologique, en mettant l'accent sur l'étude de certains facteurs spéciaux. Les Chapitres 2, 3, 4 et 5 nous permettent de développer les contributions de cette thèse. Chaque chapitre est consacré à un thème particulier et aux questions qui s'y rapportent, en théorie ergodique ou en dynamique topologique, et est associé à un article scientifique. Les structures de cube mentionnées plus haut sont toutes définies pour un espace muni d'une unique transformation. Dans le Chapitre 2, nous introduisons une nouvelle structure de cube liée à l'action de deux transformations S et T qui commutent sur un espace métrique compact X. Nous étudions les propriétés topologiques et dynamiques de cette structure et nous l'utilisons pour caractériser les systèmes qui sont des produits ou des facteurs de produits. Nous présentons également plusieurs applications, comme la construction des facteurs spéciaux. Le Chapitre 3 utilise la nouvelle structure de cube définie dans le Chapitre 2 dans une question de théorie ergodique mesurée. Nous montrons la convergence ponctuelle d'une moyenne cubique dans un système muni deux transformations qui commutent. Dans le Chapitre 4, nous étudions le semigroupe enveloppant d'une classe très importante des systèmes dynamiques, les nilsystèmes. Nous utilisons les structures des cubes pour montrer des liens entre propriétés algébriques du semigroupe enveloppant et les propriétés topologiques et dynamiques du système. En particulier, nous caractérisons les nilsystèmes d'ordre 2 par une propriété portant sur leur semigroupe enveloppant. Dans le Chapitre 5, nous étudions les groupes d'automorphismes des espaces symboliques unidimensionnels et bidimensionnels. Nous considérons en premier lieu des systèmes symboliques de faible complexité et utilisons des facteurs spéciaux, dont certains liés aux structures de cube, pour étudier le groupe de leurs automorphismes. Notre résultat principal indique que, pour un système minimal de complexité sous-linéaire, le groupe d'automorphismes est engendré par l'action du shift et un ensemble fini. Par ailleurs, en utilisant les facteurs associés aux structures de cube introduites dans le Chapitre 2, nous étudions le groupe d'automorphismes d'un système de pavages représentatif. La bibliographie, commune à l'ensemble de la thèse, se trouve en fin document / This thesis is devoted to the study of different problems in ergodic theory and topological dynamics related to og cube structures fg. It consists of six chapters. In the General Presentation we review some general results in ergodic theory and topological dynamics associated in some way to cubes structures which motivates this thesis. We start by the cube structures introduced in ergodic theory by Host and Kra (2005) to prove the convergence in $L^2$ of multiple ergodic averages. Then we present its extension to topological dynamics developed by Host, Kra and Maass (2010), which gives tools to understand the topological structure of topological dynamical systems. Finally we present the main implications and extensions derived of studying these structures, we motivate the new objects introduced in the thesis and sketch out our contributions. In Chapter 1 we give a general background in ergodic theory and topological dynamics given emphasis to the treatment of special factors. % We give basic definitions and describe special factors associated to a From Chapter 2 to Chapter 5 we develop the contributions of this thesis. Each one is devoted to a different topic and related questions, both in ergodic theory and topological dynamics. Each one is associated to a scientific article. In Chapter 2 we introduce a novel cube structure to study the actions of two commuting transformations $S$ and $T$ on a compact metric space $X$. In the same chapter we study the topological and dynamical properties of such structure and we use it to characterize products systems and their factors. We also provide some applications, like the construction of special factors. In the same topic, in Chapter 3 we use the new cube structure to prove the pointwise convergence of a cubic average in a system with two commuting transformations. In Chapter 4, we study the enveloping semigroup of a very important class of dynamical systems, the nilsystems. We use cube structures to show connexions between algebraic properties of the enveloping semigroup and the geometry and dynamics of the system. In particular, we characterize nilsystems of order 2 by its enveloping semigroup. In Chapter 5 we study automorphism groups of one-dimensional and two-dimensional symbolic spaces. First, we consider low complexity symbolic systems and use special factors, some related to the introduced cube structures, to study the group of automorphisms. Our main result states that for minimal systems with sublinear complexity such groups are spanned by the shift action and a finite set. Also, using factors associated to the cube structures introduced in Chapter 2 we study the automorphism group of a representative tiling system. The bibliography is defer to the end of this document