Cette thèse étudie la détection de communautés dans le contexte des réseaux sociaux. Un réseau social peut être modélisé par un graphe dans lequel les sommets représentent les membres et les arêtes représentent les relations entre les membres. En particulier, j'étudie quatre différentes définitions de communauté. D'abord, une structure en communautés peut être définie par une partition des sommets telle que tout sommet a une plus grande proportion de voisins dans sa partie que dans toute autre partie. Cette définition peut être adaptée pour l'étude d'une seule communauté. Ensuite, une communauté peut être vue comme un sous graphe tel que tout couple de sommets sont à distance 2 dans ce sous graphe. Enfin, dans le contexte des sites de rencontre, je propose d'étudier une définition de communauté potentielle dans le sens où les membres de la communauté ne se connaissent pas, mais sont liés par des connaissances communes. Pour ces trois définitions, j'étudie la complexité computationnelle et l'approximation de problèmes liés à l'existence ou la recherche de telles communautés dans les graphes. / This thesis deals with community detection in the context of social networks. A social network can be modeled by a graph in which vertices represent members, and edges represent relationships. In particular, I study four different definitions of a community. First, a community structure can be defined as a partition of the vertices such that each vertex has a greater proportion of neighbors in its part than in any other part. This definition can be adapted in order to study only one community. Then, a community can be viewed as a subgraph in which every two vertices are at distance 2 in this subgraph. Finally, in the context of online meetup services, I investigate a definition for potential communities in which members do not know each other but are related by their common neighbors. In regard to these proposed definitions, I study computational complexity and approximation within problems that either relate to the existence of such communities or to finding them in graphs.

<div>This study explores historical syntactic changes within a complex network framework focusing on the development of the German verb <i>werden</i> (to become) and the emergence of the related passive and future periphrases. The data are collected from a corpus of Middle and Early New High German texts and the analysis of the instances is carried out in two different stages. The first stage focuses on the frequency of the verb <i>werden</i> and the elements that co-occurred with it throughout Middle and Early New High German. The second stage investigates the same instances through a complex network framework by applying descriptive statistics to uncover the features of the Middle and Early New High German networks that have been created with the occurrences of<i> werden</i> found in the corpus.</div><div><br></div><div><div>The results of the analysis show that <i>werden</i> experienced an increase in the type of connections it was able to establish throughout the centuries. Such a process is known in the literature as preferential attachment. This suggests that linguistic networks, and specifically, syntactic networks, are also subjected to processes that are common among non-linguistic networks.</div></div>

A multivariate generalization of mutual information, multi-information, is defined in the thermodynamic limit. The definition takes phase coexistence into account by taking the infimum over the translation-invariant Gibbs measures of an interaction potential. It is shown that this infimum is attained in a pure state. An explicit formula can be found for the Ising square lattice, where the quantity is proved to be maximized at the phase-transition point. By this, phase coexis-tence is linked to high model complexity in a rigorous way.

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In this thesis we study descriptive-set-theoretic and measure-theoretic properties of Polish groups, with a thematic emphasis on the contrast between groups which are locally compact and those which are not. The work is divided into three major sections. In the first, working jointly with Robert Kallman, we resolve a conjecture of Gleason regarding the Polish topologization of abstract groups of homeomorphisms. We show that Gleason's conjecture is false, and its conclusion is only true when the hypotheses are considerably strengthened. Along the way we discover a new automatic continuity result for a class of functions which behave like but are distinct from functions of Baire class 1. In the second section we consider the descriptive complexity of those subsets of the permutation group S? which arise naturally from the classical Levy-Steinitz series rearrangement theorem. We show that for any conditionally convergent series of vectors in Euclidean space, the sets of permutations which make the series diverge, and diverge properly, are ?03-complete. In the last section we study the phenomenon of Haar null sets a la Christensen, and the closely related notion of openly Haar null sets. We identify and correct a minor error in the proof of Mycielski that a countable union of Haar null sets in a Polish group is Haar null. We show the openly Haar null ideal may be distinct from the Haar null ideal, which resolves an uncertainty of Solecki. We show that compact sets are always Haar null in S? and in any countable product of locally compact non-compact groups, which extends the domain of a result of Dougherty. We show that any countable product of locally compact non-compact groups decomposes into the disjoint union of a meager set and a Haar null set, which gives a partial positive answer to a question of Darji. We display a translation property in the homeomorphism group Homeo+[0,1] which is impossible in any non-trivial locally compact group. Other related results are peppered throughout.

The influence of self-complexity on coping behaviour and emotional adjustment is explored. The Role Construct Repertory Grid (REPGrid) Community of Selves procedure is used to assess self-complexity. Following a structured interview format, subjects completed a battery of measures including the REPGrid, Self-Rating Depression Scale, Hassles Scale, Major Stress Scale, and Coping Index. Results indicate that complex individuals utilize a wider variety of coping behaviours than less complex individuals, although the perceived severity of stressful events was. no different between groups. Micro-analyses at the individual self level revealed mixed or null results. Finally, more dysphoric individuals reported using more negative coping behaviours (drinking, smoking) than individuals not experiencing dysphoric mood. Findings are discussed a) in terms of the utility of the REPgrid in the assessment and understanding of self-complexity and its' relationship to mental health processes, b) in accordance with a person-event transactional model of health and illness, and c) in terms of the relevance to those psychotherapies that emphasize and encourage people to develop distinctions among their self-aspects, as well as new ways of construing the world, and new behavioural options, e.g. Fixed Role Therapy.

As the impacts of climate change intensify, businesses are increasingly committing to ambitious sustainable development goals, yet an enduring disconnect remains between corporate sustainability activities and declining global environment and society. This study adopts a complexity view that reductionism associated with Newtonian thinking has played a key role in creating many of the sustainability issues now faced by humanity. This dissertation departs from the premise that sustainability needs to be integrated into an organisation and uses a complexity view to argue that corporate sustainability is a co-evolutionary process of emergence. Whilst many studies have examined how sustainability can be integrated into a business, less is known about corporate sustainability as an emergent process. To address the knowledge gap, this research answered three questions: (1) How does sustainability emerge in financial institutions? (2) What is the role of coherence in the emergence of sustainability? and (3) What conditions enable the emergence of sustainability? A mixed method sequential design was used. In the initial quantitative strand of the research, a holistic business assessment survey based on integral theory was implemented in two financial services organisations in Southern Africa. The results were analysed using self-organising maps and explored in narrative interviews in the subsequent qualitative strand of the research. The study makes three contributions to our understanding of emergence in corporate sustainability. First, by proposing four modes by which corporate sustainability is enacted; these elucidate how integral domains are enacted in corporate sustainability. Second, by clarifying the process of emergence by articulating how zones of coherence emerge between embodied and embedded dimensions. Third, by explaining how the shift to corporate sustainability occurs by means of four conditions. These contributions serve to advance our understanding of corporate sustainability as a fundamental shift in the functioning of an organisation towards coevolutionary self-organisation. It is recommended that corporate sustainability is holistically cultivated to support emergence and self-organisation, rather than being integrated through a linear process of change.

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This study is an examination of how a word’s syntactic category, word length, and usage frequency might impact a speaker’s use of communicative pause. Previously collected between and within utterance language samples from 21 people with aphasia (Harmon, 2018) were evaluated in this study. Participants consisted of 11 individuals diagnosed with mild or very mild aphasia and 10 individuals with moderate aphasia;15 who exhibited fluent subtypes and 6 non-fluent subtypes of aphasia. Data from the Corpus of Contemporary American English (COCA) was used to code the word frequency and syntactic category of each word in the language samples. Generally, speakers with both non-fluent and fluent aphasia produced more monosyllabic words of very high frequency with a greater percentage of function words than content words. Analyses revealed no significant correlations between the pause duration for either the word length or word frequency for either group of speakers. In relation to syntactic category, no significant differences in pause duration were found between content and function words in the between utterance condition. However, non-fluent speakers preceded content words with significantly shorter pause durations within utterances when compared with the function words. Due to differences in sample sizes between the speaker and syntactic groups, non-parametric statistics were used for some comparisons. In addition, this study does not fully account for the influence of fillers and incomplete words. Despite these limitations, this study will contribute to the research regarding communicative speech pause in speakers with aphasia and provide insight into more useful diagnostic and treatment strategies.

Aim The study aim was to explore the issues and challenges facing undergraduate nursing education in one Canadian province from an institutional theory perspective. The research questions were: What is the institutional field of nursing education? What are the issues and challenges facing nursing education? How is the institutional field of nursing education contributing to the issues and challenges? How are the issues and challenges contributing to the institutional complexity? Background Nursing education is essential for the health care of society, yet face various issues and challenges at the system level. Institutional theory has been used in higher education to better understand how higher education institutions are structured and operate. Institutional theory has not been used in nursing education. The issues facing nursing education have been examined from a critical or descriptive perspective, but a system-level perspective is missing. Institutional theory could fill this gap and examine the institution of nursing and how its structure, behaviours, and rules influence those issues and challenges. Methods An exploratory single-case study with embedded units design was used. Theoretical propositions from institutional theory informed the sample, recruitment, data collection, and data analysis. In 2019, representatives from organizations comprising the institutional field of nursing education and senior-level administrators were interviewed and relevant documents were collected and reviewed. The data were analyzed using deductive and inductive thematic analysis, building a case description, and visual analysis techniques. Findings The findings from sixty documents and seven interviews suggested the institutional field of nursing education is composed of postsecondary institutions, health service organizations, the regulatory body, the ministry for health, and the ministry for postsecondary education. The issues and challenges facing nursing education included demands on curricula, teaching and learning values versus practice, the relationship between education and practice, limiting financial supports, clarity of the RN role, and need for faculty. The institutional field of nursing education is complex and includes dominant organizations, such as the regulatory body and health service organization, and the non-dominant organization, postsecondary institutions. Discussion / Conclusion The use of institutional theory was beneficial to explore the issues and challenges facing undergraduate nursing education from a system-level perspective and captured the complexity within the system. The institutional field including the influences of structure, dominance, and complexity impact the issues and challenges facing nursing education. The institutional perspective of the issues and challenges diverges from previous examinations. In addition, the use of institutional theory in higher education offers strategies for advocacy in nursing education. Recommendations for nursing education practice, policy, and research include: (a) awareness of the organizations comprising the institutional field of nursing education, (b) including the nursing education accreditation body and the professional association within the interorganizational structures, (c) acknowledgement of the sources of dominance within the field, and (d) developing strategies for academic nurse leaders to navigate the complexity of nursing education. The most urgent consideration arising from this research is the dominant forces from regulation and health service organizations and the subsequent non-existence of the professional voice of nursing for nursing education within the institutional field. / Graduate