Ce travail de thèse vise à comprendre les dynamiques sociales qui viennent influencer le processus d’appropriation d’une technologie SNA au sein d’une organisation. Pour ce faire, nous avons mené une étude inter-cas menée au sein de deux collectivités territoriales françaises et une étude intra-cas chez BOUYGUES CONSTRUCTION en nous appuyant sur un cadre théorique mobilisant la théorie de l’acteur stratégique de Crozier et Friedberg et la théorie de la pratique de Bourdieu. Un des principaux résultats de cette thèse est que l’appropriation d’une technologie SNA passe principalement par une appropriation socio-politique en deux phases : une phase d’appropriation de la nouvelle dimension donnée au capital social et une phase d’appropriation de la technologie pour servir les intérêts des acteurs concernant le développement du capital social. Nous avons également identifié que l’introduction d’un outil SNA est assignée à différentes notions symboliques (symbole de la légitimité du contrôle et de la supervision, symbole du soutien du top-management des pratiques de travail transversales, le symbole de la rigidité des structures organisationnelles, le symbole de la gestion des ressources informelles comme une ressource spécifique, le symbole de l’exclusion…) qui viennent légitimer et asseoir les différentes stratégies des groupes d’acteurs. Enfin, nous avons constaté que certains symboles liés à l’introduction du SNA sont étroitement liés à la culture de l’organisation. Ces principaux résultats ont pu être confortés par l’étude intra-cas menée chez BOUYGUES CONSTRUCTION, présentée comme une étude d’un cas particulier pouvant complémenter l’investigation menée au sein des deux collectivités territoriales. / This thesis aims to understand the social dynamics that influences actors’ adoption of a SNA tool in an organization. We have conducted multiple-case studies of two French Administrations (Mayoral offices) and an additional single case referred to a French industry BOUYGUES CONSTRUCTION drawing on Crozier and Friedberg’s theory of strategic actor and Bourdieu’s theory of practice. The first principle result is that the adoption of a SNA technology is primarily a socio-political appropriation that occurs through two phases: in the first phase actors discover social capital as a new symbolic capital and in a second phase they use the technology to influence the development of the organizational social capital in order it can serve their own interests. We have also identified that the introduction of a SNAS tool is assigned to different symbolic notions (symbol of the legitimization for control and supervision, symbol of top-management support for the development of transversal work practices, symbol of the rigidity of organizational structure, symbol of the management of informal resource as specific resource, symbol of exclusion) useful to provide legitimacy to the actors’ strategies in organizations. Finally, we highlight that these symbolic notions appear connected to the organizational culture. These key findings have emerged from our multiple-case study and have been reinforced the additional single case studied in BOUYGUES CONSTRUCTION. This single case complements the investigation conducted in the two Mayoral offices.

La notion de communauté, transverse à  l'analyse des réseaux sociaux, a attiré une attention grandissante à  travers les sciences ces dix dernières années. Les nombreuses tentatives pour modéliser aussi bien l'incarnation sociologiquedu concept aussi bien que sa manifestation structurelle dans le réseau social n'ont jusqu'à  présent que vaguement convergé. Aucun consensus formel n'a été atteint sur les aspects quantifiables de la communauté, et ceci malgré lesliens forts la reliant aux dimensions dynamique et topologique du réseau sous-jacent.Présentant une approche novatrice à  l'évaluation des communautés, cette thèse introduit et se base sur la cohésion, une métrique qui capture la qualitéintrinsèque, en tant que communauté, d'un ensemble de sommets dans un réseau. Il a été montré au travers d'une experience à  large échelle, dans laquelle les individus sondés ont pu noter l'aspect communautaires de groupes d'amis leur étant présentés, que la cohésion, définie en lien avec la notion de triades sociales, est fortement correlée à  la perception subjective de la communauté. Reflétant la complexité des interactions sociales, il est démontré que leproblème de trouver des communautés maximalement cohésive est NP-dur. En utilisant une heuristique approximant les résultats de ce problème, un certain nombre d'applications de la cohésion à  des données réelles sont mises en avant: de son application à  la visualisation de réseaux complexes, à  l'étude de l'évolution des groupes d'agrément du sénat états-unien, à  la compréhesion des liens entre psychologie et structure du réseau social.L'utilisation de la cohésion apporte un éclairage non trivial dans l'étude de la structure des grands réseaux de terrain et dans la relation entre structure et sémantique. / Community, a notion transversal to all areas of Social Network Analysis, has drawn tremendous amount of attention across the sciences in the past decades. Numerous attempts to characterize both the sociological embodiment of the concept as well as its observable structural manifestation in the social network have to this date only converged in spirit. No formal consensus has been reached on the quantifiable aspects of community, despite it being deeply linked to topological and dynamic aspects of the underlying social network. Presenting a fresh approach to the evaluation of communities, this thesis introduces and builds upon the cohesion, a novel metric which captures the intrinsic quality, as a community, of a set of nodes in a network. The cohesion, defined in terms of social triads, was found to be highly correlated to the subjective perception of communitiness through the use of a large-scale online experiment in which users were able to compute and rate the quality of their social groups on Facebook. Adequately reflecting the complexity of social interactions, the problem of finding a maximally cohesive group inside a given social network is shown to be NP-hard. Using a heuristic approximation algorithm, applications of the cohesion to broadly different use cases are highlighted, ranging from its application to network visualization, to the study of the evolution of agreement groups in the United States Senate, to the understanding of the intertwinement between subjects' psychological traits and the cohesive structures in their social neighborhood. The use of the cohesion proves invaluable in that it offers non-trivial insights on the network structure and its relation to the associated semantic.

The central goal of this dissertation has been mapping, discussing and making sense of the political activities undertaken by Belgian Moroccan, Belgian Turkish and Belgian Congolese organisations based in Brussels. I therefore identified these organisations in the national register of moral personalities. I furthermore administered a standardised questionnaire among a representative sample of the registered organisations. I focused in this questionnaire on both what I call institutional and non-institutional political activities. In making sense of the political activities by ethnic minority organisations I started this dissertation with a focus on the hypothesis developed by the Dutch scholars Fennema and Tillie on the importance of the degree of ethnic civic community. They argue a positive association between a high level of collaboration within a particular ethnic minority associative field on the one hand and a high level of political participation that is observed among the associative elite on the other. They argue an aggregate effect following a high degree of ethnic civic community. It would not only affect the political activity undertaken by the organisations that are involved in the collaborations but also the political activity of those not involved and thereby it is thought to influence the level of participation of the entire ethnic minority associative field. To operationalise this hypothesis Fennema and Tillie designed an index for the measurement of the degree of ethnic civic community. They measure the level of collaboration among the ethnic minority organisations by mapping the interlocking directorates that occur in the ethnic minority associative field. They identify in other words the directors that are seating in the administrative board of more than one organisation. The index is composed by 4 different measures that are summed in one aggregate score. To discuss the aggregate effect they confront the ranking the ethnic minority group holds on both the index and on the level of political participation. For the Amsterdam case they find a strong parallel between both. They find the Turkish group to stand out compared to the Moroccan and Surinamese both in regard to the degree of ethnic civic community and concerning the level of political participation. During the process that has been this dissertation I gradually changed the initial hypothesis. I argue on the one hand that Fennema and Tillie put a too strong emphasis on the presence of interlocking directorates to operationalize the idea of ethnic civic community. I argue the importance to consider equally the collaborations that occur in the daily practice of the organisations. I furthermore argue the pertinence to discuss the collaborations that ethnic minority organisations establish with the Brussels mainstream autochthonous associative field. I argue on the other hand that they put too little emphasis on contextual elements. I argue the importance to consider characteristics of the political setting in which the organisations are operating and to the social inequality and power imbalances that characterises the relation between ethnic minority and majority groups. I equally argue the importance of considering the presence of other than social resources that characterises the ethnic minority associative field and to pay attention to the anchoring of the Belgian Moroccan, Belgian Turkish and Belgian Congolese group in the Belgian society. I basically argue that these contextual elements can interact with the ethnic civic community hypothesis. Based on these arguments I created a more complex research design in which I discuss both the importance of bonding and bridging social capital and in which I essentially argue the multidimensional relation between the two multi-facetted concepts of social capital and political participation. I argue that bonding and bridging collaborations can have a differential influence on the outcome of political participation according to the political activity that is considered. I argue that the direction of the relation is shaped by elements of the Brussels setting. I argue that the importance of the degree of ethnic civic community for the Brussels case could well be limited to the non-institutional dimension of political participation. I find for the Brussels case the Belgian Moroccan group to obtain the highest score on the index of ethnic civic community. The network of interlocking directorates is characterised by the presence of large clusters of interconnected organisations and a high level of connectivity. The Belgian Turkish and Belgian Congolese group share a second position in this regard. However I do not find the Belgian Moroccan associative field to be more politically active as compared to both other groups, neither concerning institutional political activities, nor regarding non-institutional activities. I observe in fact very few differences in the level of political participation across the three ethnic minority groups I study in Brussels. I do not find any statistical significant difference regarding electoral participation, involvement in consultation and the participation to claim making activities. I find only one significant difference between the groups and this concerns the presence of direct of particularized contacting of public or political authorities. However I do not find the Belgian Moroccan group to stand out in this regard. I find on the other hand the Belgian Turkish associative field to hold a first position. I do in other words not find a parallel between the ranking the three groups hold on the index of ethnic civic community and the ranking the Belgian Moroccan, Belgian Turkish and Belgian Congolese group show as for the level of political activities undertaken by the associative elite. I read in this result a strong empirical evidence to reject the Fennema and Tillie hypothesis. However I argue that comparing the rank order that the groups hold on both independent and dependent variable essentially equals confronting uni-variate analyses and therefore is not fit to study an association between both type of variables. A third variable could for instance act as a suppressor or mediator variable making it as such impossible to make sense of the presence or absence of a parallel. I therefore argue the importance of studying the individual effect prior to discussing the aggregate effect. I additionally discuss the individual association between being embedded in the network of interlocking directorates on the one hand and the outcome on the different indicators of political participation. I thereby pay attention to the particular position an organisation holds within the network but also to the possible interactions that can occur with other than social resources of an organisation. For the Brussels case I only find one main individual effect. I find being part of one of the larger components to reliably predict the outcome concerning the direct or particularized contacting of representatives of political institutions. I find this to be true for all three groups, but in particular for the Belgian Moroccan group. However the particular strong association I observe for the Belgian Moroccan organisations does not coincide with a highest group level of particularized contacting. On the contrary, I find the Belgian Turkish group to show a significant higher level of this type of political activity, followed by the Belgian Congolese. Based on these observations, I reject for the Brussels case the hypothesis on the aggregated effect following the size and structure of the network of interlocking directorates. I either do not find an individual effect or in case I find an individual effect it does not add to the understanding of the differences in the level of political participation I find across the three groups. If it is not the size and the structure of the network of interlocking directorates that allows to make sense of the level of political activity observed among an ethnic minority associative elite for the Brussels case, what is then? To answer this question I explore the individual effect of other types of collaborations and of other than social resources an organisation has to its disposition. Across these analyses, I find two independent variables to be of particular importance to understand the political participation by ethnic minority organisations. I find the information on receiving public funding and on being involved in collaborations with Brussels pro-migrant associative life to predict most reliably the outcomes on the different dependent variables on political participation except as for the variable on electoral participation. In uni-variate analyses I find moreover that these two resources attain relatively similar levels for the three ethnic minority groups. I understand the similarities I find across the three groups concerning the level of participation to consultation and to claim making activities strongly by referring to the predominant influence of these two resources. I note that the presence of these resources is strongly determined by the decisions that are made at the institutional level. I argue that the similar opportunities the Belgian Moroccan, Belgian Turkish and Belgian Congolese organisations meet within the Brussels institutional and political setting are strongly important in shaping the access to consultation and claim making. However I equally find that resources that are located within the ethnic minority associative field as for example the presence of an advocacy mission still adds to the understanding of these types of political participation, even after controlling for the information on public funding and contacts with the pro-migrant associative field. I argue notwithstandingthat top down processes in Brussems outnumber bottom-up processes to understand the participation of the ethnic minority organisations to consultative mechanisms and to claim making. The same can be argued concerning the involvement of the organisations in the electoral process. I find similar levels of electoral participation across the three ethnic minority associative fields. However I do not find an influence of public funding or of an embeddedness in Brussels mainstream autochthonous associative field in this regard. I do not find any of the selected independent variables to reliably predict the outcome on the dependent variable. In my entire database I find only one characteristic of the organisations to allow a reliable prediction concerning the outcome on electoral participation namely that on the presence of personal relations with Brussels political parties. I argue therefore that the link between ethnic minority associative life and the electoral process is structured not so much by a systematic knowledge of which are the larger, more established or more influential organisations but by processes of personal acquaintanceship. I interpret this result by referring to the presence of assimilationist perspective on integration that is predominant in Brussels. I argue that this predominant discourse creates obstacles for that leaders of strongly resourceful ethnic minority organisations are seen as more legitimate actors to access institutional political arena. To sum up, I understand the similarities that I find across the three group concerning the level of political participation by referring to both the similar opportunities and obstacles they meet in the Brussels context. A last question that then remains concerns the difference I observe between the group concerning the level of direct contacting of representatives of the institutional political arena. I understand the first position the Belgian Turkish group holds in this regard by referring to the Turkish migration history and the particular anchoring of the group in Belgian society. I refer in particular to the more collective integration strategy that characterises this group, as compared to both other groups. I understand the second position that is hold by the Belgian Congolese group by referring to the significant higher level of two resources that occur within the Belgian Congolese associative field. I find the significant higher level of advocacy organisations and of an organising along community interests to add strongly to the understanding of the higher level of direct contacting as compared to the Belgian Moroccan group. To end with I point to the fact that the differences I observe on direct contacting are all the more remarkable since the number of elected politicians of Moroccan origin in Belgium is strongly higher as compared to the number of elected politicians of Turkish and Congolese origin. I argue that the favourable position the Belgian Moroccan group holds at the individual level concerning the access to the institutional political arena is not repeated at the collective level. On the contrary I observe an inverse relation. I therefore argue that this difference in direct contacting between the Belgian Moroccan organisations on the one hand and the Belgian Turkish and Congolese on the other should at least partly be understood in terms of a compensatory mechanism for the lack of opportunities these communities hold at the individual level. This compensatory mechanism is supported and made possible by resources that are located within the ethnic minority associative fields. I find these resources however not to be social resources, but to concern the presence of a strong collective group identity and of an intrinsic political motivation. I started this dissertation with the hypothesis on the importance of internal collaboration to understand the differences and similarities in the level of political participation undertaken by the Belgian Moroccan, Belgian Turkish and Belgian Congolese associative field. However instead of bonding social capital I find the presence of public funding of bridging social capital and of characteristics of the Brussels context and of the ethnic minority groups to be of more importance for understanding both institutional and non-institutional political activities. However this does not mean that the level of internal collaboration is of no importance at all to make sense of the political activity undertaken by ethnic minority organisations in Brussels. Even after controlling for the presence of other resources, I find that the presence of internal collaborations adds to the contentious capacity of ethnic minority organisations. I find the presence of informal collaborations to add to the understanding of the presence of proclaiming activities. I find an embeddedness in the network of interlocking directorates to reliably predict the outcome on direct contacting. If it were not for the organisations involved in the network of interlocking directorates, the level of particularised contacting would be much lower in Brussels, in particular for the Belgian Moroccan group. Although the first position the Belgian Moroccan group holds on the index of ethnic civic community did not show to be a good predictor for finding a higher level of political participation among the Belgian Moroccan associative elite, it still is meaningful in the more restricted sense that the Belgian Moroccan network more strongly as compared to both other networks adds to the understanding of the level of direct contacting. To end with I find the hypothesis on the multidimensional relation between two multifaceted concepts of social capital and political participation to be confirmed for the Brussels case. Bonding and Bridging social capital relate differently to the outcomes on political participation according to the type of political activity. I moreover find the hypothesis on the importance of taking into account contextual elements to make sense of the direction of these relations to be equally confirmed. The interpretation of the empirical results I collected has not been possible without referring to characteristics of the Brussels context, of the three ethnic minority groups and of the particular anchoring of these groups in Belgian society. / Doctorat en Sciences politiques et sociales / info:eu-repo/semantics/nonPublished

Le principal objectif de cette thèse est d'évaluer les protocoles qui prennent en considération la protection de la vie privée et qui nécessitent seulement des métadonnées locales pour détecter les comportements malveillants sur les réseaux sociaux décentralisés. En appliquant des techniques d'analyse de réseaux sociaux qui réduisent la quantité de métadonnées sensibles, nous obtenons des résultats acceptables comparé aux techniques qui ne préservent pas la vie privée. De plus, nous prévoyons d'élaborer une série de recommandations pour construire de futurs réseaux sociaux décentralisés qui découragent cette type des comportements abusifs. / The main goal of this thesis is to evaluate privacy-preserving protocols to detect abuse in future decentralised online social platforms or microblogging services, where often limited amount of metadata is available to perform data analytics. Taking into account such data minimization, we obtain acceptable results compared to techniques of machine learning that use all metadata available. We draw a series of conclusion and recommendations that will aid in the design and development of a privacy-preserving decentralised social network that discourages abusive behavior.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

La visualisation d'informations est un domaine qui connaît un réel intérêt depuis une dizaine d'années. Dernièrement, avec l'explosion des moyens de communication, l'analyse de réseaux sociaux fait l'objet de nombreux travaux de recherches. Nous présentons dans cette thèse des travaux sur l'analyse de réseaux sociaux dynamiques, c'est à dire que nous prenons en compte l'aspect temporel des données. [...] / Since ten years, informations visualization domain knows a real interest.Recently, with the growing of communications, the research on social networks analysis becomes strongly active. In this thesis, we present results on dynamic social networks analysis. That means that we take into account the temporal aspect of data. We were particularly interested in communities extraction within networks and their evolutions through time. [...]

De nos jours, la popularité des réseaux sociaux (RS) est en constante progression. En effet, de plus en plus d’utilisateurs interagissent dans le monde virtuel, soit en y exprimant des opinions, en partageant des expériences, en réagissant aux avis d’autrui ou encore en échangeant des idées, en fonction de leurs qualités : influents, populaires, dignes de confiance, etc.. Dans la littérature, l’influence a fait l'objet d'une attention particulière ces dernières années. En effet, de nombreux domaines, dont l’Analyse des Réseaux Sociaux (ARS) et les systèmes de recommandation ont étudié l’influence, sa détection, la propagation de son effet et sa mesure. Ainsi, des modèles d'identification et d'estimation de l'influence sont aujourd'hui largement utilisés dans de nombreuses applications dédiées au marketing, aux campagnes politiques/sociales, etc. De plus, les interactions entre utilisateurs indiquent non seulement l’influence mais aussi la confiance, la popularité ou la réputation. Cependant, ces notions sont encore vaguement définies et il n'existe pas de consensus dans la communauté ARS. Définir, distinguer et mesurer la force de ces relations entre les utilisateurs posent également de nombreux défis, à la fois théoriques et pratiques, qui restent à explorer. La modélisation de l’influence pose de multiples défis et les méthodes actuelles de découverte et d’évaluation n’explorent pas encore pleinement les différents types d’interactions et ne sont en général pas applicables à plusieurs RS. En outre, la prise en compte de la dimension temporelle dans le modèle d’influence est importante, difficile et nécessite un examen plus approfondi. Enfin, l’exploration de liens possibles entre des notions, telles que l’influence et la réputation, reste un sujet ouvert. Dans cette thèse, nous nous focalisons sur les quatre concepts qualifiant les utilisateurs : influence, réputation, confiance et popularité, pour la modélisation de l'influence. Nous analysons les travaux existants utilisant ces notions et comparons leurs différentes interprétations. Par cette analyse, nous mettons en avant les caractéristiques essentielles que ces concepts devraient inclure, et nous en effectuons une analyse comparative. Cela nous permet d'établir une classification globale des différentes interprétations des notions selon leur niveau d'abstraction et leurs divergences ; cela constitue la première, contribution de cette thèse. En conséquence, nous proposons un modèle théorique de l'influence ainsi qu'une ontologie associée décrivant ce concept. Nous présentons également une variante de l'influence, inexplorée à ce jour dans le domaine de l’ARS, la micro-influence. Celle-ci cible un phénomène nouveau dans les RS que sont les utilisateurs avec une faible audience, mais fortement impliqués ; ces derniers apparaissent en effet comme ayant un impact fort malgré tout. En s'appuyant sur ces définitions, nous proposons ensuite un modèle pratique dénommé ARIM (Action-Reaction Influence Model). Ce modèle considère le type, la qualité, la quantité et la fréquence des actions réalisées par les utilisateurs, et ce en étant compatible avec différents RS. Nous abordons également la quantification de l'influence au cours du temps et la représentation de ses effets de causalité. Pour cela, nous considérons un type spécifique de RS: les réseaux de citations, particulièrement sensibles au temps. Ainsi, nous proposons un modèle, TiDIE (Time Dependent Influence Estimation), qui détermine l'influence, sur une période de temps, entre les communautés de ces réseaux. Enfin, nous combinons l’influence et la réputation avec le modèle TiDIE, afin d’étudier les dépendances entre elles. Nous proposons une méthode de transition, ReTiDIE, utilisant l’influence pour obtenir la réputation. Pour chacune de nos approches, des expérimentations ont été menées sur des jeux de données réels et ont montré la pertinence de nos méthodes / Online social networks are constantly growing in popularity. They enable users to interact with one another and shifting their relations to the virtual world. Users utilize social media platforms as a mean for a rich variety of activities. Indeed, users are able to express their opinions, share experiences, react to other users' views and exchange ideas. Such online human interactions take place within a dynamic hierarchy where we can observe and distinguish many qualities related to relations between users, concerning influential, trusted or popular individuals. In particular, influence within Social Networks (SN) has been a recent focus in the literature. Many domains, such as recommender systems or Social Network Analysis (SNA), measure and exploit users’ influence. Therefore, models discovering and estimating influence are important for current research and are useful in various disciplines, such as marketing, political and social campaigns, recommendations and others. Interestingly, interactions between users can not only indicate influence but also involve trust, popularity or reputation of users. However, all these notions are still vaguely defined and not meeting the consensus in the SNA community. Defining, distinguishing and measuring the strength of those relations between the users are also posing numerous challenges, on theoretical and practical ground, and are yet to be explored. Modelization of influence poses multiple challenges. In particular, current state-of-the-art methods of influence discovery and evaluation still do not fully explore users’ actions of various types, and are not adaptive enough for using different SN. Furthermore, adopting the time aspect into influence model is important, challenging and in need of further examination part of the research. Finally, exploring possible connections and links between coinciding notions, like influence and reputation, remains to be performed.In this thesis, we focus on the qualities of users connected to four important concepts: influence, reputation, trust, and popularity, in the scope of SNA for influence modeling. We analyze existing works utilizing these notions and we compare and contrast their interpretations. Consequently, we emphasize the most important features that these concepts should include and we make a comparative analysis of them. Accordingly, we present a global classification of the notions concerning their abstract level and distinction of the terms from one another, which is a first and required contribution of the thesis. Consequently, we then propose a theoretical model of influence and present influence-related ontology. We also present a distinction of notion not yet explored in SNA discipline -- micro-influence, which targets new phenomena of users with a small but highly involved audience, who are observed to be still highly impactful. Basing on the definitions of the concepts, we propose a practical model, called Action-Reaction Influence Model (ARIM). This model considers type, quality, quantity, and frequency of actions performed by users in SN, and is adaptive to different SN types. We also focus on the quantification of influence over time and representation of influence causal effect. In order to do that, we focus on a particular SN with a specific characteristic - citation network. Indeed, citation networks are particularly time sensitive. Accordingly, we propose Time Dependent Influence Estimation (TiDIE), a model for determining influence during a particular time period between communities within time-dependent citation networks. Finally, we also combine two of the abovementioned notions, influence and reputation, in order to investigate the dependencies between them. In particular, we propose a transition method, ReTiDIE, that uses influence for predicting the reputation. For each of the proposed approaches, experiments have been conducted on real-world datasets and demonstrate the suitability of the methods

Cette thèse a pour objectif d’étudier la façon dont les individus vivent ensemble et développent des relations ancrées dans un contexte international. Ces espaces sont marqués par une densité importante de situations d’interaction au jour le jour, où l’imprévisibilité est constante. Observer l’évolution des acteurs dans ces situations problématiques où ils disposent de peu d’habitudes, de standards, de manières d’être et de faire prédéfinies, permet d’apprécier le développement de leurs compétences d’innovation et d’ajustement et notamment de suivre la constitution d’un ordre d’interaction. Pour cela, j’ai mené trois enquêtes ethnographiques comparatives dans trois résidences universitaires internationales : deux Maisons Internationales en France (Fondation Ulysse à la Cité Internationale Universitaire de Paris) et aux États-Unis (l’International House) et une troisième dans une Graduate House au Canada. Ces trois terrains sont relativement similaires sur plusieurs points : la population y est constituée d'étudiants diplômés de licence de différents domaines d'études, avec une forte proportion d'étudiants étrangers et internationaux ; les conditions de vie sont également comparables (cuisines collectives et sanitaires, salles communes, organisation d'une vie communautaire [community life]). Par ailleurs, les deux premières maisons portent un programme institutionnel similaire, activant une idéologie internationaliste. Leur comparaison et celle avec la troisième résidence universitaire permettra de saisir différentes ingénieries institutionnelles, parties prenantes dans la production d’une normativité pratique. Après avoir présenté les terrains, les méthodes et l’objet d’étude (chapitre introductif), nous suivrons plusieurs questions qui ont émergé sur les terrains d’enquête : la temporalité des sociabilités au cours d’un séjour (chapitre 1) le passage de relations d’anonymes aux relations ancrées (chapitre 2), la coproduction d’un ordre d’interaction, d’une idioculture et d’un ordre social (chapitre 3), une réflexion autour des commérages (chapitre 4) et enfin une réflexion sur les ingénieries institutionnelles et leurs engagements dans les sociabilités des résidents et leur normativité pratique (chapitre 5). En somme, cette recherche contribue aux travaux en sociologie et en micropolitique des sociabilités, en sociologie des petits groupes, en sociologie des réseaux personnels et en sociologie de la communication. / My thesis aims to study how people live together and develop relationships in an international context. These situations are marked by the fact that nobody masters beforehand these collective settings; indeed, they are marked by interactional unpredictability. How do individuals manage to live together, when they share almost no common rules, and no pre-defined shared ways of being? How do they develop personal relationships, and end by building up affinity relationships? What kind of skills of understanding and evaluation, innovation and adjustment, do they have to activate? In order to get a better knowledge of such situations, since 2011, I have conducted three ethnographic fieldworks: two in International Houses in France (Fondation Ulysse at the Cité Internationale Universitaire de Paris) and the United States, and a third one in a Graduate House in Canada. These three residences have relatively similar general settings: the population is graduate students from different fields of study, with a large proportion of foreign and international students, also the living conditions are comparable (collective kitchens and sanitary facilities, communal rooms, organization of a community life). In addition, the first two residences carry a similar institutional project, advocating an internationalist ideology. The comparison between these houses, and with the Canadian residence, will allow us to grasp the institutional engineerings and the practical normativity coproduced by current residents in each house. After introducing the fieldworks, the methods and the research questions (introductionnary chapter), we will study several questions which emerged from the surveys: the temporality of sociabilities during a stay in student residency (chapter 1), the passage of anonymous relationships to anchored relationships (chapter 2), the co-production of an order of interaction, of an idioculture and of a social order (chapter 3), a reflection on gossip (chapter 4) and finally a study on institutional engineering and their engagement towards residents’ sociabilities and their practical normativity (chapter 5). In sum, this research contributes to sociology and micropolitics of sociability, sociology of small groups, sociology of social networks, and sociology of communication.

La vasière intertidale de Brouage, écosystème très étudié localement de longue date, a fait l’objet depuis 5 ans d’analyses plus approfondies notamment sur le devenir du biofilm microbien se formant à la surface des sédiments à marée basse. Ce travail de thèse s’inscrit dans cette optique. Il propose, par le couplage d’outils mathématiques et écologiques, d’analyser le réseau trophique de la vasière de Brouage sous différentes conditions abiotiques à partir de la synthèse des données les plus récentes. La modélisation inverse a permis d’estimer les flux manquants du réseau trophique. Les calculs d’indices d’analyse des réseaux écologiques ou ENA (Ecological Network Analysis) ont caractérisé la structure et le fonctionnement du réseau trophique.Un premier travail méthodologique, basé sur la dégradation-reconstruction d’un jeu de données très complet, a défini la meilleure fonction, la moyenne, pour le choix d’une seule solution pour chaque flux à la sortie de la modélisation inverse. La moyenne est la meilleure fonction puisque son utilisation aboutit à une bonne estimation des flux manquants quel que soit le niveau d’information intégré au modèle. Cette fonction permet aussi une bonne préservation de la structure et du fonctionnement du réseau trophique ainsi reconstruit. Le réseau trophique de la vasière de Brouage à basse mer a été étudié sous un aspect saisonnier par l’opposition de l’été et de l’hiver, l’hiver étant caractérisé par la présence d’oiseaux migrateurs sur la vasière. L’activité limicole des oiseaux est soutenue en hiver par une forte production du microphytobenthos et un fort recyclage de la matière. L’organisation interne et la spécialisation des flux restent cependant semblables pour les deux saisons considérées. Dans un deuxième temps, le réseau trophique à pleine mer en été a été modélisé sous différentes conditions hydrodynamiques permettant ou pas la remise en suspension du biofilm microbien. La comparaison entre ces deux situations met en évidence l’effet de la remise en suspension sur le couplage benthos-pelagos. Le système soumis à la remise en suspension présente un très faible indice de recyclage lié à la faible intégration au réseau trophique pélagique du carbone particulaire benthique remis en suspension. De plus, la remise en suspension provoque une augmentation de l’activité du système couplée à une faible spécialisation des flux, ce qui est supposé déstabiliser le système. / The Brouage mudflat is an intertidal ecosystem which has been studied locally for a long time. During the last 5 years, in depth studies have especially focused on the fate of the microbial biofilm which develops at the surface of the sediments at low tide. The present Ph.D. work was accomplished in this framework. It proposes, through the synthesis of the most recent data, to combine mathematical and ecological tools to analyze the Brouage food web under different abiotic conditions. The inverse modeling allowed estimating the unknown flows of the food web. The calculation of the ENA (Ecological Network Analysis) indices characterized the structure and the functioning of the food web. A methodological work, based on the degradation/reconstruction of a complete data set, determined the best function, the mean, to choose a single solution for each flow among the set of values estimated by the inverse modeling. The mean is the best function because it leads to a good estimation of the unknown flows irrespective of the quantity of information integrated in the model. Moreover, this function allows a good conservation of the structure and functioning of the reconstructed food web.The Brouage food web at low tide was investigated with a seasonal approach by the opposition of the summer and the winter food webs, the latest being characterized by the presence of migratory shorebirds. The shorebird activity is sustained by a strong primary production and a strong recycling. Nevertheless, the internal organization and the specialization remain similar for the two seasons. In a second step, the food web at high tide was modeled under different hydrodynamical conditions sufficient or not to induce the resuspension of the microbial biofilm. The comparison between the two food webs highlights the effect of the resuspension on the benthos-pelagos coupling. The recycling activity is low due to the low integration of the resuspended benthic particulate carbon in the pelagic food web during resuspension. Additionally, the resuspension leads to an increase of the activity of the whole system coupled with a drop of the specialization of the trophic pathways that is supposed to destabilize the system.

Cette thèse traite de l'usage de l'annotation socio-sémantique dans le cadre de la dé-mocratie électronique et plus particulièrement des débats en ligne. L'annotation socio-sémantique est utilisée ici comme solution de structuration des débats. La représentationdes données des débats est pensée pour faciliter la mise en place de méthodes d'extrac-tion et d'analyses du réseau social des utilisateurs, en particulier pour faciliter l'extractionde groupes d'opinions. La thèse est réalisée dans le contexte de l'ANR Intermed qui vise àproduire des outils d'aide à la concertation en ligne, en particulier pour la gestion de zonescôtiéres.En nous appuyant sur la tendance 2.0, nous définissons la notion de débat 2.0. Débat àgrande échelle, au moins l'échelle d'une collectivité territoriale, s'appuyant sur l'usage detechnologies du Web 2.0 pour faciliter les interactions entre les citoyens. Dans ce contexte,l'interopérabilité est un enjeu crucial. Si les annotations discursives s'inscrivent dans latendance 2.0 et permettent aux citoyens de discuter en ligne, le traitement des donnéesproduites en vue de structurer les débats, de synthétiser les discussions, de modérer, d'éva-luer la représentativité ... devient une tâche de plus en plus complexe avec l'augmentationde la quantité de données produites. Nous proposons d'utiliser les technologies du websémantique, et donc des annotations à la fois discursives et sémantiques (appelées anno-tations socio-sémantique), pour représenter les données produites par les citoyens dansun outil de débat 2.0 et pour faciliter l'interopérabilité de ces données, faciliter la créationd'autres services comme par exemple un service d'analyse du réseau social, un service derecommandation, un service de visualisation des débats ... Nous présentons donc un mé-canisme d'annotation structurant les discussions, fruit d'un processus incrémental d'im-plémentation et d'expérimentation sur le terrain. / This pdh deals with socio-semantic annotations for e-democracy and online debates. Socio-semantic annotation are used to structurate debates. Data representation was designed to facilitate social network analysis and community detection based on opinion mining. This phd was made during the ANR project Intermed wich has to develop e-participation tools for geolocalised planning.Based on Web 2.0 trend, we define debate 2.0 concept as great scale online debates. A debate 2.0 is a debate that involves at least an important part of the inhabitants of a county and that uses web 2.0 tools. Interoperability is a main challenge of debates 2.0. If discursive annotations are a web 2.0 way of interaction between citizen, to process data from citizen participation is a complicate and expensive task. We recommand to use web semantic technology and socio-semantic annotations to represent data produced by citizen. Il will increase interoperability and easiness to create new applications and features consuming this data. We propose an annotation mecanism to structurate discussions and we have developped a platform through an agile loop with on field experiment.