• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 606
  • 302
  • 135
  • 132
  • 92
  • 74
  • 63
  • 40
  • 28
  • 26
  • 21
  • 12
  • 12
  • 11
  • 7
  • Tagged with
  • 1779
  • 1779
  • 659
  • 228
  • 227
  • 188
  • 165
  • 164
  • 157
  • 149
  • 138
  • 136
  • 131
  • 128
  • 120
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
491

Community level serious leisure networks

Lawrence Bendle Unknown Date (has links)
Abstract Drawing on the serious leisure perspective, social world theory, and social network analysis this thesis utilizes an exploratory methodology to develop a structural view of a social world network of 49 social actors comprised of the grassroots associations and the allied organisations expressly concerned with amateur artists in a regional Australian city. Semistructured interviews were conducted with spokespeople in leadership and management roles with the associations and organisations. The purpose of the interviews was to develop an understanding of the key attributes of the grassroots associations and the function of the allied commercial, cultural, and educational organisations, and to discover the patterns of links between these two types of social actors. In addition, the interviews explored the types of social world participation among the associational memberships; and the role, rewards, and costs experienced by the spokespeople who were fulfilling coordinating duties in the grassroots associations. The research found that associations of amateur artists were active in the local community coordinating their memberships, activities, and assets to provide calendars of events for the participants in a regional social world of the creative arts and that, the allied organisations provided complementary goods and services. Further, it emerged that links of varying intensity connecting the associations and organisations coalesced into a network. This comprised a cluster of social actors connected by their concern with actors, dancers, and musicians; a cluster of social actors connected by their concern with craft practitioners, community cultural development workers, visual artists, and writers; and of social actors with bilateral links connecting the two clusters. Also mixed serious leisure emerged as a significant mode of participation among the sample of grassroots association spokespeople who were interviewed and this was important to the sustainability of their associations over time. There are three major outcomes from the research. First, structural concepts from social network analysis in combination with social world theory developed into definition of a community level serious leisure network; second, this definition proved empirically viable in the research context, and third, a model to depict the phenomenon of a community level serious leisure network has emerged from the exploratory process. The findings have both theoretical and empirical implications. Theoretically, they assist research into the structure of community level leisure provision. The findings also encourage investigation of mixed serious leisure. Empirically, the application of network knowledge to improve community leisure resources can improve the outcomes for the social actors involved and the community in which they are embedded.
492

Masculinities in local contexts: structural, individual and cultural interdependencies

Lusher, Dean Stewart Unknown Date (has links) (PDF)
Knowledge of the terms sex and gender has important political, health and equity considerations. This thesis investigates the macrostructural assertions of Connell’s social theory of gender which is fundamentally concerned with demonstrating the relational and hierarchical nature of gender. A major criticism of the theory has been its lack of account of the individual and the ways in which gender is performed in local settings. Therefore, investigation primarily concerns whether Connell’s macrostructural theory is explicable in local social contexts. A theoretical critique and reframing of the theory lead to articulating the interdependency between structural, cultural and individual factors. By explicitly stating Connell’s implicit assertions, what becomes evident is that people’s gendered relations are interrelated with beliefs which are held personally and shared culturally. Specifically, a major theoretical impasse is overcome when recognising that the “ideology of supremacy” of a dominative masculinity is necessarily interdependent with the structural relations of power. / From here I have suggested that there are particular patterns of these structures and beliefs which can be seen in macrostructural terms, but also in local settings. These hypotheses are reframed into social network terms for an empirical investigation of Connell’s theory in local contexts. To determine whether the predicted hypotheses for Connell’s theory occur at greater than chance levels, a particular type of statistical model for social networks, called exponential random graph (p*) models, is employed. Importantly, such models utilize a methodological approach which specifically acknowledges the interdependency of structural, individual and cultural factors, thus aligning Connell’s theory with the method of investigation. / Primarily, Connell’s theory is concerned with differing configurations of masculinity, and for this reason my focus is predominantly on males and their relations with one another. To this end, two general local settings were chosen to explore these issues – secondary schools and all-male elite-level (AFL) sporting teams. Social network models were used to examine the relations between masculinities in six schools and four AFL clubs. Importantly, Connell has suggested that local contexts are likely to differ from one another in the degree to which they support gendered relations of power. Results for schools and clubs vary considerably from one another in the ways in which they provide local level support for Connell’s theory. Significantly though, there are some contexts which do show support for Connell’s theory. That such evidence can be found to endorse specifically defined local-level predictions for Connell’s theory, even when controlling for complex micro-level social structures, and also for other individual level effects, and still produce statistically significant effects supporting these predictions suggests that support is not trivial. There is strong evidence that attitudes towards masculinity can be an important organising principle in the emergence of hierarchy, not universally, but in some contexts. / It can be concluded that gender relations tend to operate in ways predicted by Connell’s theory, though local context is particularly important. The specific findings from local social contexts do have wider implications for Connell’s theory, including how hierarchy in gender can be tied to other structures of power, where femininities fit into the theory, a more precise account of hegemony and an exploration of the impact culture has in local settings.
493

Understanding Attitudes towards Performance in Knowledge-intensive Work: The Influence of Social Networks and ICT Use

Chung, Kon Shing Kenneth January 2008 (has links)
Doctor of Philosophy (PhD) / Understanding factors that enhance or diminish performance levels of individuals is instrumental for achieving individual (low level) and organisational (high level) goals. In this study, the effect of social network structure, position, ties and information and communication technologies (ICT) use on performance attitudes of knowledge intensive workers in dispersed occupational communities is investigated. Based on social network theories of strength of weak ties and structural holes, and the social influence model of technology use, a theoretical framework is developed. In conjunction with qualitative interviews conducted with subject matter experts, the framework is used to further develop and refine a valid and reliable survey instrument. Secondly, network measures of degree centrality, density, structural holes (constraint and efficiency), tie strength and tie diversity are applied for exploring the association with ICT use and performance from a sample of 110 rural general practitioners. Empirical results suggest that network structure, position and ties of knowledge workers play a crucial role in individual performance and ICT use. In particular, degree centrality and task-level ICT use was found to be positively associated with performance while ego-network constraint was found to be negatively correlated with performance. In terms of ICT use, functional diversity and degree centrality were positively associated with task-level ICT use whereas ego-network efficiency was found to be negatively correlated with ICT use at the communication-structure level. Among the variables that showed significance, degree centrality best explained overall variance for performance, and functional diversity best explained overall variance for task-level ICT use, although professional accreditations remains a potent indicator also. The results from this study resonate with findings from past literature and extend traditional theory of social networks and performance within the micro level to include geographically dispersed individuals involved in knowledge intensive work. For individuals in such non-competitive settings, traditional network theories such as structural holes theory still apply. However, a key finding is that network structure is a much more potent predictor of performance although network position is important. The second key finding addresses a major gap in the literature concerning understanding social processes that influence ICT use. As the technology acceptance and the social influence models lack empirical evidence from a social networks perspective, this research shows that rather than the strength of ties which functions as a conduit of novel ideas and information, it is the functional tie diversity within individual professionals networks that increase ICT use at the task-level. Methodologically, the study contributes towards a triangulation approach that utilises both qualitative and quantitative methods for operationalising the study. The quantitative method includes a non-traditional “networks” method of data collection and analysis to serve as a fine complement to traditional research methods in behavioural studies. The outcome is a valid and reliable survey instrument that allows collection of both individual attribute and social network data. The instrument is theoretically driven, practically feasible to implement, time-efficient and easily replicable for other similar studies. At the domain level, key findings from this study contradict previous literature which suggests that professionals in occupational communities such as general practitioners decline in performance as they age. In fact, findings from this study suggest that age and experience do not affect for performance; rather, there is a negative relationship between experience and task-level ICT use, and that task-level ICT use is positively associated with performance in terms of attitudes to interpersonal care. Furthermore, degree centrality is also positively associated with professional accreditations, such as fellowship of the Royal Australian College of General Practitioners, which is conducive to performance in terms of attitudes to interpersonal and technical care. The contextual implication from the quantitative and qualitative evidence of this study is that while contemplating strategies for optimising ICT use or for improving attitudes to quality of care at the technical and interpersonal level, the importance of social structure, position and relations in the practitioner’s professional network needs to be considered carefully as part of the overall individual and organisation-level goals.
494

Constructing Learning Conversations: A Study of the Discourse and Learner Experiences of Online Synchronous Discussions

hlim@pi.ac.ae, Hwee Ling Lim January 2006 (has links)
The aim of this qualitative case study is to gain greater insight into the impact of online synchronous (chat) interaction on the learning process from a sociocultural constructivist perspective in the context of an online undergraduate unit. Given the sparse research on the effectiveness of chat interaction in supporting knowledge construction processes, few appropriate analytical methods available for examining educational chat discourse, together with the pedagogical imperative to determine the extent to which the real-time computer-mediated communication (CMC) mode satisfies student learning needs, this study fills the gaps in current research by examining the impact of chat interaction in facilitating participation, knowledge construction, and quality of online learning experience of two different online tutorial groups. Although the literature largely regards chat interaction as fragmented and characterized by interactional incoherence that disrupts the dialogic knowledge construction process, findings from this single-embedded case study of tutorial groups 1 and 4 (G1 and G4), involved in weekly critical discussions on set-readings over 11 weeks (one semester), show that chat interaction is more structured and complex than the literature suggests. This study utilizes a new methodological design that integrates discourse and social network analytical methods which are triangulated with self-reports of learning experiences from an online survey instrument. The application of a refined Exchange Structure Analysis coding instrument (Kneser, Pilkington, & Treasure-Jones, 2001) with social network analysis (Wasserman & Faust, 1994; Scott, 2000) to transcripts of chat interaction shows educational chat discourse to be coherent; reflecting the typical structure of pedagogical classroom exchanges. Findings from this study further establish that chat interaction enables participation opportunities in tutorial discussions which are valued as important, with variations in levels of participation within and between groups suggesting a pattern of active and peripheral participation which is not necessarily detrimental to learning. Chat interaction is also found to facilitate collaborative sharing of individual understandings and critical negotiation of meaning which are characteristic of the knowledge construction process, in the form of information-sharing and topic development phases in the exchanges of both groups. Although it is beyond the scope of this study to determine the exact form of knowledge constructed, individual and mutual appropriations of shared knowledge through chat interaction are reported by both groups. A between group comparison of available tutor scaffolding reveals consistently weak G1 tutor presence compared to strong G4 tutor support at the initial learning stages with gradual withdrawal of scaffolding over time. These results suggest differences in quality of online educational experiences which are confirmed by findings that compared to G1, G4 reported greater satisfaction with more chat tutorial factors; indicating an overall more positive, higher quality of experience with collaborative learning and group work processes afforded by the chat interaction. With its methodological design, instruments, and findings, this study contributes to existing knowledge on online interaction, advances on previous studies regarding impact of chat interaction on learning, and offers directions for future work in the fields of educational technology, linguistics, and group dynamics in educational social networks. When extrapolated to comparable cases, findings from this study could guide the pedagogical design of collaborative-constructivist learning activities that takes into account the role of chat interaction in the construction of learning conversations.
495

Towards a broader understanding of coordination in software engineering: a case study of a software development team

Panjer, Lucas David Greaves 15 August 2008 (has links)
Coordination of people, processes, and artifacts is a significant challenge to successful software engineering that is growing as the scale, distribution, and complexity of software projects grow. This thesis presents an exploratory case study of coordination of interdependent work in a practicing software development team. Qualitative analysis of stakeholder interviews was used to develop nine theoretical propositions that describe coordination behaviours. One proposition was refined by quantitatively exploring the structure of explicit dependencies between work items in relation to their resolution times. Structure measures drawn from social network analysis were used to quantify the structure of explicit dependencies between work items, revealing some lower resolution times were associated with degree centrality measures, but that network structures only explain a small proportion of the variance in resolution times. The results are compared with existing theories of coordination in software engineering and directions for further research are outlined.
496

Modelagem sociotécnica de uma organização nuclear: estudo de caso aplicado ao laboratório Nacional de Metrologia das Radiações Ionizantes / Sociotechnical modelling of a nuclear organization case study applied to the Ionizing Radiation Metrology National laboratory

Maria Elizabeth Dias Acar 09 November 2015 (has links)
Uma metodologia que combina mapeamento e análise de processos, elicitação, mapeamento e análise crítica de conhecimentos e análise sociotécnica com base em análise de redes sociais foi concebida. A metodologia foi aplicada à uma pequena organização intensiva conhecimento LNMRI e permitiu a avaliação dos seus principais ativos intelectuais e sua capacidade de evoluir. Nesse sentido, com base em questões reais, tal como a saída de pessoas da organização, foram avaliados os impactos de prováveis cenários futuros. Para tal tarefa, foi analisada uma rede multimodal de processos, objetos de conhecimento e pessoas, utilizando-se um conjunto apropriado de métricas e meios, incluindo a avaliação das esferas de influências de nós chave. Para diferenciar a capacidade das pessoas em desempenhar diferentes papeis nos processos, alguns atributos dos nós foram utilizados como critérios de partição da rede, proporcionando assim, a capacidade de diferenciar o impacto da perda potencial de supervisores e operadores. A metodologia proposta possibilitou: i) a identificação de objetos de conhecimento e de suas fontes; ii) a classificação desses objetos segundo sua relevância; iii) a avaliação de vulnerabilidades da estrutura da rede LNMRI e iv) revelou os mecanismos informais de partilha de conhecimento. A metodologia concebida demonstrou ser uma ferramenta robusta para um amplo diagnóstico para subsidiar o planejamento de sucessão e também o planejamento estratégico organizacional. / A methodology combining process mapping and analysis; knowledge elicitation mapping and critical analysis; and sociotechnical analysis based on social network analysis was conceived. The methodology was applied to a small knowledge intensive organization LNMRI, and has allowed the appraisal of the main intellectual assets and their ability to evolve. In this sense, based on real issues such as attrition, the impacts of probable future scenarios were assessed. For such task, a multimodal network of processes, knowledge objects and people was analyzed using a set of appropriate metrics and means, including sphere of influence of key nodes. To differentiate the ability of peoples role playing in the processes, some nodes attributes were used to provide partition criteria for the network and thus the ability to differentiate the impact of potential loss of supervisors and operators. The proposed methodology has allowed for: i) the identification of knowledge objects and their sources; ii) mapping and ranking of these objects according to their relevance and iii) the assessment of vulnerabilities in LNMRIs network structure and iv) revealing of informal mechanisms of knowledge sharing The conceived methodological framework has proved to be a robust tool for a broad diagnosis to support succession planning and also the organizational strategic planning.
497

De l'idée au projet : les parcours des créateurs d'entreprise jeunes et seniors

Roser Parmentier, Paméla 17 November 2015 (has links)
Cette thèse porte sur les créateurs d’entreprise, jeunes et seniors, qui à un moment donné de leur carrière professionnelle, ont effectué un changement de parcours au cours duquel ils ont décidé de construire et de développer leur entreprise. Cette étude nous apprend que "monter sa boite" ne relève pas du coup de tête, mais fait l’objet d’un processus réfléchi et réaliste, processus risqué qui est analysé ici comme une action autant sociale qu’individuelle, et comme le fruit d’un cheminement personnel, cheminement allant jusqu’à la transformation et au repositionnement identitaire. Nous montrons que, contrairement à ce que l’on pourrait penser, il ne s’agit pas d’une activité individuelle. Si elle est pour une part solitaire, l’action des entrepreneurs se construit en lien et souvent en coopération tant avec des institutionnels qu’avec des réseaux plus informels. Des entretiens avec les institutionnels, une observation participante dans une formation ont permis de mettre en évidence le contenu des accompagnements sociaux institutionnalisés. Les entretiens avec les créateurs montrent l’apport différencié des réseaux sociaux, ceux des liens forts et ceux des liens faibles. Dans cette thèse, nous analysons le cheminement de l’idée originelle de l’individu jusqu'à l’élaboration du projet puis sa mise en place. De l’idée initiale, au projet abouti, il existe un certain nombre d’étapes qui sont nécessaires et importantes, demandant au porteur du projet une adaptabilité et une capacité de changement. Le porteur de projet en passant par ces différentes étapes sera confronté à des phases de doutes générant des remises en question. Il s’agit de comprendre comment les futurs entrepreneurs se projettent dans leur nouveau statut, évaluent ce "challenge" professionnel. Habiter ce nouveau statut, passer du monde salarial au monde patronal, leur demande une véritable réflexion sur l’orientation de la carrière et une prise de conscience des risques familiaux, financiers et identitaires. La thèse explicite des configurations de trajectoires professionnelles, leur articulation à la vie familiale et sociale. Elle met en évidence les différences de parcours mais aussi de sens que la création d’entreprise revêt selon l’âge. Les séniors et les jeunes ne sont pas non plus armés de la même manière. Ainsi les savoirs d’expérience et de formation s’articulent différemment selon les parcours. Ce choix, cette mise en action constitue pour eux une "seconde carrière". Les manières de construire et de mener les projets révèlent également des différences selon le genre. / This doctoral thesis deals with young and over-fifties business creators who, at a time during their professionnal career have decided of a change so as to start and develop their own business.This research tells us that "starting up one's own place" is far from being a whim, but it is the result of a realistic and thoughtful project ; a risked process which is seen here both as a social and personal action and as the result of a personal development. This development is going up to a personal change and to an identity repositioning. We prove that, the process is not the result of an individual activity only. Of course, it's partly an individual action, but this action is also built in link and in cooperation with both institutions and more informal networks. Conversations with institutions as well as participating observations in a training period have revealed the contents of the institutionalized social supports. Conversations with the creators show the different contributions of the social networks, those with strong links and those with weak links. In this thesis, we analize the progress from the original idea in the individual's mind until the elaboration of the project and finally to its ' setting up'. From the initial idea to the accomplished project, there is a number of stages which are both necessary and important; as a consequence, the leader of the project must be able to adapt and to have a change capacity. Getting through these various stages, the leader of the project will have to face periods of doubt generating questionings.It's a question of understanding how the future entrepreneurs fall in the new statute and estimate this professional chalenge. Living this new statute and passing from the wage world to the employers' world, asks them a real thought on the orientation of their career as well as the awareness of the family, financial and identical risks. The thesis explains configurations of careers and their link with social and family life. It reveals the differences of careers and of sense that the new business involves according to the age. The over-fifties and the young people are differently equipped. Thus, the experience and training knowledge link differently according to the careers. This choice, the action constitute "a second career" for them. The way the projects are built and led also reveals differences according to the gender.
498

Les usages des réseaux socionumériques : la mise en visibilité de soi sur Facebook / Uses of social network sites : self-exposure on Facebook

Mell, Laurent 28 November 2014 (has links)
La massification des usages des réseaux socionumériques n’est pas sans conséquences sur la visibilité dont les individus font l’objet. Les potentialités d’internet dans la diffusion de l’information et les divers services de communication mis à disposition sont autant de mécanismes de dévoilement de l’intimité de l’usager dans les espaces publics numériques.Notre projet de recherche doctoral propose d’appréhender les pratiques et l'ensemble des facteurs associés au phénomène de mise en visibilité de soi sur les réseaux socionumériques, et plus particulièrement sur Facebook.Pour ce faire, cette recherche s’appuie sur une analyse quantitative, issue de la passation d’un questionnaire en ligne auprès de 444 usagers de Facebook, ainsi que sur une analyse qualitative provenant de 27 entretiens réalisés auprès d’utilisateurs du réseau socionumérique.Il s’agit de comprendre les raisons expliquant l’élaboration de pratiques de régulation de la visibilité numérique face à un réseau socionumérique incitant à une exposition de soi accrue.Il apparaît que les usagers sont en mesure de développer des espaces de visibilité de leurs informations personnelles et sont en constante variation afin de gérer la complexité de l’identité numérique. Ensuite, les évolutions de la visibilité des individus sur Facebook ne se réalisent pas de manière linéaire mais s’opèrent davantage par phases, entendues comme des interventions dans les pratiques de gestion de la vie privée. Ces évolutions correspondent à des épisodes de vie concomitants à l’expérience d’usage. Enfin, Le dispositif sociotechnique, ou plutôt les invitations à la mise en visibilité de soi qu’il émet, tout comme les attentes normatives de la « société » sont tout autant des modalités de définition de l’identité de l’usager des réseaux socionumériques. Les facteurs d’invitation à la mise en visibilité de soi – que sont l’usager lui-même ; son réseau de relations ; le dispositif sociotechnique Facebook ; et la « société » sous le trait des attentes normatives imposées – correspondent, en grande partie, aux mécanismes de prévention contre les potentielles atteintes à la vie privée. / The increase of the use of social network sites has consequences regarding individual privacy. The Internet’s capability to disseminate information and various communication services available is also a mechanism that reveals the privacy of the user in digital public spaces.Our doctoral research project proposes to study the practices and whole of the factors associated with the phenomenon of self-exposure on social network sites, especially on Facebook.This research contains a quantitative analysis, based on an online questionnaire to 444 Facebook users, as well as a qualitative analysis from 27 interviews conducted with users of this social network site.It aims to analyze the reasons that explain the development of regulatory practices of digital visibility caused by a social network site that incites increased self-exposure.It appears that users are able to develop spaces of visibility of their personal information and that they modulate their practices in order to manage the complexity of the digital identity. Then, changes in individuals’ visibility on Facebook do not occur a linear fashion but in phases, defined as interventions in the management practices of privacy. These changes correspond to instances of life that are concurrent to the experience of use. Finally, the socio-technical system, or rather the invitations to self-exposure so that it emits, as the normative expectations of the "society" are equally ways of defining the identity of the user of social network sites. Factors invitation to self-exposure - that is the user himself; its network of relationships; the socio-technical device Facebook; and "society" under the related normative expectations it imposes - correspond largely to preventive mechanisms guarding against potential threats to privacy.
499

DSL pour la fouille des réseaux sociaux sur des architectures Multi-coeurs / DSL (Domain Specific Language) for Social Network Analysis on multicore architectures

Messi Nguele, Thomas 15 September 2018 (has links)
Les réseaux complexes sont des ensembles constitués d’un grand nombre d’entités interconnectées par des liens. Ils sont modélisés par des graphes dans lesquels les noeuds représentent les entités et les arêtes entre les noeuds représentent les liens entre ces entités. Ces graphes se caractérisent par un très grand nombre de sommets et une très faible densité de liens. Les réseaux sociaux sont des exemples de réseaux complexes où les entités sont des individus et les liens sont les relations (d’amitié, d’échange de messages) entre ces individus.L’analyse des réseaux complexes est généralement basée sur l’exploration locale du graphe sous-jacent : après avoir traité un nœud u, les prochains noeuds auxquels l’application fait référence appartiennent au voisinage de u. Étant donné que le graphe sous-jacent est habituellement non structuré, les séquences d’accès aux données en mémoire tendent à avoir une faible localité lorsque qu’on utilise par exemple le stockage de Yale qui est l’un des meilleurs connus. En plus, dans les applications basées sur l’analyse des réseaux le nombre de calculs requis pour chaque noeud peut être très variable, ce qui, dans les mises en œuvre parallèles (multithreadées), se traduit par un déséquilibre de charges entre les threads.Le travail réalisé dans cette thèse était lié au développement d’applications d’analyse des réseaux sociaux, qui soient à la fois faciles à écrire et efficaces. A cet effet, deux pistes ont été explorées: a)L’exploitation de la structure en communautés pour définir des techniques de stockage qui réduisent les défauts de cache lors de l’analyse des réseaux sociaux; b)La prise en compte de l’hétérogénéité des degrés des noeuds pour optimiser la mise en oeuvre parallèle.La première contribution de cette thèse met en évidence l'exploitation de la structure en communautés des réseaux complexes pour la conception des algorithmes de numérotation des graphes (NumBaCo, CN-order) permettant la réduction des défauts de cache des applications tournant dans ces graphes.Les résultats expérimentaux en mode séquentiel sur plusieurs architectures (comme Numa4) ont montré que les défauts de cache et ensuite le temps d'exécution étaient effectivement réduits; et que CN-order se sert bien des avantages des autres heuristiques de numérotation (Gorder, Rabbit, NumBaCo) pour produire les meilleurs résultats.La deuxième contribution de cette thèse a considéré le cas des applications multi-threadées. Dans ce cas, la réduction des défauts de cache n'est pas suffisante pour assurer la diminution du temps d'exécution; l'équilibre des charges entre les threads doit être assuré pour éviter que certains threads prennent du retard et ralentissent ainsi toute l'application. Dans ce sens, nous nous sommes servis de la propriéte de l'hétérogénéité des dégrés des noeuds pour développer l'heuristique Deg-scheduling. Les résultats expérimentaux avec plusieurs threads sur l'architecture Numa4 montrent que Deg-scheduling combiné aux heuristiques de numérotation permet d'obtenir de meilleur résultats.La dernière contribution de cette thèse porte sur l'intégration des deux catégories d'heuristiques développées dans les DSLs parallèles d'analyse des graphes. Par exemple, avec le DSL Green-Marl, les performances sont améliorées à la fois grâce aux heuristiques de numérotation et grâce aux heuristiques d’ordonnancement (temps réduit de 35% grâce aux heuristiques). Mais avec le DSL Galois, les performances sont améliorées uniquement grâce aux heuristiques de numérotation (réduction de 48%). / A complex network is a set of entities in a relationship, modeled by a graph where nodes represent entities and edges between nodes represent relationships. Graph algorithms have inherent characteristics, including data-driven computations and poor locality. These characteristics expose graph algorithms to several challenges, because most well studied (parallel) abstractions and implementation are not suitable for them. The main question in this thesis is how to develop graph analysis applications that are both --easy to write (implementation challenge), -- and efficient (performance challenge)? We answer this question with parallelism (parallel DSLs) and also with knowledge that we have on complex networks (complex networks properties such as community structure and heterogeneity of node degree).The first contribution of this thesis shows the exploitation of community structure in order to design community-aware graph ordering for cache misses reduction. We proposed NumBaCo and compared it with Gorder and Rabbit (which appeared in the literature at the same period NumBaCo was proposed). This comparison allowed to design Cn-order, another heuristic that combines advantages of the three algorithms (Gorder, Rabbit and NumBaCo) to solve the problem of complex-network ordering for cache misses reduction. Experimental results with one thread on Core2, Numa4 and Numa24 (with Pagerank and livejournal for example) showed that Cn-order uses well the advantages of the other orders and outperforms them.The second contribution of this thesis considered the case of multiple threads applications. In that case, cache misses reduction was not sufficient to ensure execution time reduction; one should also take into account load balancing among threads. In that way, heterogeneity of node degree was used in order to design Deg-scheduling, a heuristic to solve degree-aware scheduling problem. Deg-scheduling was combined to Cn-order, NumBaCo, Rabbit, and Gorder to form respectively Comm-deg-scheduling, Numb-deg-scheduling, Rab-deg-scheduling and Gor-deg-scheduling. Experimental results with many threads on Numa4 showed that Degree-aware scheduling heuristics (Comm-deg-scheduling, Numb-deg-scheduling, Rab-deg-scheduling and Gor-deg-scheduling) outperform their homologous graph ordering heuristics (Cn-order, NumBaCo, Rabbit, and Gorder) when they are compared two by two.The last contribution was the integration of graph ordering heuristics and degree-aware scheduling heuristics in graph DSLs and particularly Galois and Green-Marl DSLs. We showed that with Green-Marl, performances are increased by both graph ordering heuristics and degree-aware scheduling heuristics (time was reduced by 35% due to heuristics). But with Galois, performances are increased only with graph ordering heuristics (time was reduced by 48% due to heuristics).In perspective, instead of using complex networks properties to design heuristics, one can imagine to use machine learning. Another perspective concerns the theoretical aspect of this thesis. We showed that graph ordering for cache misses reduction and degree-aware scheduling for load balancing problems are NP-complete. We provided heuristics to solve them. But we didn't show how far these heuristics are to the optimal solutions. It is good to know it in the future.
500

Characterizing Online Social Media: Topic Inference and Information Propagation

Rezayidemne, Seyedsaed 31 October 2018 (has links)
Word-of-mouth (WOM) communication is a well studied phenomenon in the literature and content propagation in Online Social Networks (OSNs) is one of the forms of WOM mechanism that have been prevalent in recent years specially with the widespread surge of online communities and online social networks. The basic piece of information in most OSNs is a post (e.g., a tweet in Twitter or a post in Facebook). A post can contain different types of content such as text, photo, video, etc, or a mixture of two or more them. There are also various ways to enrich the text by mentioning other users, using hashtags, and adding URLs to external contents. The goal of this study is to investigate what factors contribute into the propagation of messages in Google+. To answer to this question a multidimensional study will be conducted. On one hand this question could be viewed as a natural language processing problem where topic or sentiment of posts cause message dissemination. On the other hand the propagation can be effect of graph properties i.e., popularity of message originators (node degree) or activities of communities. Other aspects of this problem are time, external contents, and external events. All of these factors are studied carefully to find the most highly correlated attribute(s) in the propagation of posts.

Page generated in 0.0714 seconds