Dissertations / Theses on the topic 'Social interactions'

Online social media, such as Facebook, Twitter, and LinkedIn, provides users with services that enable them to interact both globally and instantly. The nature of social media interactions follows a constantly growing pattern that requires selection mechanisms to find and analyze interesting data. These interactions on social media can then be modeled into interaction networks, which enable network-based and graph-based methods to model and understand users’ behaviors on social media. These methods could also benefit the field of complex networks in terms of finding initial seeds in the information cascade model. This thesis aims to investigate how to efficiently collect user-generated content and interactions from online social media sites. A novel method for data collection that is using an exploratory research, which includes prototyping, is presented, as part of the research results in this thesis.   Analysis of social data requires data that covers all the interactions in a given domain, which has shown to be difficult to handle in previous work. An additional contribution from the research conducted is that a novel method of crawling that extracts all social interactions from Facebook is presented. Over the period of the last few years, we have collected 280 million posts from public pages on Facebook using this crawling method. The collected posts include 35 billion likes and 5 billion comments from 700 million users. The data collection is the largest research dataset of social interactions on Facebook, enabling further and more accurate research in the area of social network analysis.   With the extracted data, it is possible to illustrate interactions between different users that do not necessarily have to be connected. Methods using the same data to identify and cluster different opinions in online communities have also been developed and evaluated. Furthermore, a proposed method is used and validated for finding appropriate seeds for information cascade analyses, and identification of influential users. Based upon the conducted research, it appears that the data mining approach, association rule learning, can be used successfully in identifying influential users with high accuracy. In addition, the same method can also be used for identifying seeds in an information cascade setting, with no significant difference than other network-based methods. Finally, privacy-related consequences of posting online is an important area for users to consider. Therefore, mitigating privacy risks contributes to a secure environment and methods to protect user privacy are presented.

La tesi indaga i rapporti che intercorrono tra i processi percettivi e inferenziali, la struttura delle interazioni sociali e i comportamenti individuali.
This dissertation investigates the relationship between individual behaviours, the structure of social interactions, and the agents' perceptual and reasoning processes.

Il lavoro tratta gli effetti delle interazioni sociali tra compagni di scuola o di classe (c.d. peer effects) sugli apprendimenti degli studenti delle scuole medie. Il periodo di frequenza della scuola media rappresenta un momento critico nello sviluppo dell’adolescente che passa molto tempo con i compagni (a scuola e fuori da scuola) determinando forti legami di amicizia che ne influenzano lo sviluppo. Nel primo e nel secondo capitolo si tratta dell’effetto delle interazioni sociali tra studenti nativi e non nativi sull’apprendimento. Il terzo capitolo analizza il comportamento di cheating durante gli esami ufficiali come una forma di collaborazione che scaturisce da interazioni sociali. Il lavoro contribuisce alla letteratura esistente identificando gli effetti delle interazioni sociali con metodi innovativi e fornendo un’interpretazione stilizzata dei risultati mediante semplici modelli teorici. La tesi utilizza una banca dati innovativa che unisce i risultati dei test Invalsi in matematica e italiano (Esame Finale del I Ciclo, e Programma di Valutazione Nazionale, a.s. 2007-08, 2008-09, 2010-11), a dati amministrativi sulle scuole e dati censuari sulla popolazione (Censimento 2001). I risultati mostrano che le interazioni sociali influenzano in maniera significativa i risultati scolastici degli studenti.
I focus on social interactions among junior high school students attending the same class or the same school. Junior high school is generally considered by educational psychologists as the period in which friendships ties are usually formed and interactions with school mates take a relevant part of students’ time at school and outside school. In first and in the second chapter I focus on the effect on attainment of social interactions between native and non-native students. The third chapter deals with students’ cheating as a form of social interaction among classmates taking an official exam. The thesis contributes to the existing literature in proposing different empirical strategy to identify social interactions parameters and linking the results to stylized theoretical frameworks to shed light on the possible social mechanisms driving the estimated effects. The three chapters exploit rich and newly available datasets combining test score results in Math and Language from INVALSI (First Cycle Final Exam and National Evaluation Program, s.y. 2007-08, 2008-09, 2010-11), school administrative records, and the Italian Population Census Survey 2001. The results of the research demonstrate a strong role played by social interactions among school mates in affecting students’ attainment.

Il lavoro tratta gli effetti delle interazioni sociali tra compagni di scuola o di classe (c.d. peer effects) sugli apprendimenti degli studenti delle scuole medie. Il periodo di frequenza della scuola media rappresenta un momento critico nello sviluppo dell’adolescente che passa molto tempo con i compagni (a scuola e fuori da scuola) determinando forti legami di amicizia che ne influenzano lo sviluppo. Nel primo e nel secondo capitolo si tratta dell’effetto delle interazioni sociali tra studenti nativi e non nativi sull’apprendimento. Il terzo capitolo analizza il comportamento di cheating durante gli esami ufficiali come una forma di collaborazione che scaturisce da interazioni sociali. Il lavoro contribuisce alla letteratura esistente identificando gli effetti delle interazioni sociali con metodi innovativi e fornendo un’interpretazione stilizzata dei risultati mediante semplici modelli teorici. La tesi utilizza una banca dati innovativa che unisce i risultati dei test Invalsi in matematica e italiano (Esame Finale del I Ciclo, e Programma di Valutazione Nazionale, a.s. 2007-08, 2008-09, 2010-11), a dati amministrativi sulle scuole e dati censuari sulla popolazione (Censimento 2001). I risultati mostrano che le interazioni sociali influenzano in maniera significativa i risultati scolastici degli studenti.
I focus on social interactions among junior high school students attending the same class or the same school. Junior high school is generally considered by educational psychologists as the period in which friendships ties are usually formed and interactions with school mates take a relevant part of students’ time at school and outside school. In first and in the second chapter I focus on the effect on attainment of social interactions between native and non-native students. The third chapter deals with students’ cheating as a form of social interaction among classmates taking an official exam. The thesis contributes to the existing literature in proposing different empirical strategy to identify social interactions parameters and linking the results to stylized theoretical frameworks to shed light on the possible social mechanisms driving the estimated effects. The three chapters exploit rich and newly available datasets combining test score results in Math and Language from INVALSI (First Cycle Final Exam and National Evaluation Program, s.y. 2007-08, 2008-09, 2010-11), school administrative records, and the Italian Population Census Survey 2001. The results of the research demonstrate a strong role played by social interactions among school mates in affecting students’ attainment.

Les interactions sociales se trouvent au cœur des activités économiques. Pourtant en sciences économiques, elles ne sont traitées que d'une manière limitée en se concentrant uniquement aux rapports de qu'elles entretiennent avec le marché (Mankiw and Reis, 2002). Le rôle que jouent les interactions sociales vis-à-vis des comportements des agents, ainsi que la formation de leurs attentes sont souvent négligé. Cette négligence reste d'actualité malgré que les premières contributions dans la littérature économique les ont depuis longtemps déjà identifiées comme étant de déterminants importants pour la prise des décisions des agents économiques, comme par exemple Sherif (l936), Hyman (1942), Asch (1951), Jahoda (1959) ou Merlon (1968). En revanche, dans les études de consommation (une spécialité au croisement entre les sciences économiques, de la sociologie et de la psychologie), les interactions sociales (influences sociales) sont con­sidérées comme les " ... déterminants dominants[ ... ] du comportement de l'individu ... " (Burnkrant and Cousineau, 1975). Le but de cette thèse est de construire un pont entre les interactions sociales et leur influence sur la formation des anticipations et le comportement des agents
Social interactions are in the core of economic activities. Their treatment in Economies is however often limited to a focus on the market (Manski, 2000). The role social interactions themselves play for the behavior of agents as well as the formation of their attitudes is often neglected. This is despite the fact that already early contributions in economic literature have identified them as important determinants for the decision making of economic agents as for example Sherif (I936), Hyman (1942), Asch (1951 ), Jahoda (I 959) or Merton (1968). ln consumer research, a field on the intersection between Economies, Sociology and Psychology, on the other hand social interactions (social influences) are considered to be the" ... most pervasive determinants [ ... ] of individual 's behaviour. .. " (Bumkrant and Cousineau, 1975). The thesis at hand bridges the gap between social interactions and their influence on agents expectation formation and behavior

Empirical and theoretical investigations of aspects of the ideal free distribution (IFD) are presented, with particular emphasis on interactions between individuals within foraging groups. An overview of the theory is presented, and the implications of the work included in this thesis to ideal free distribution theory are discussed. The effect of group size on the relative competitive ability of individual fish within a foraging group is shown to be dependent upon the difference in body size between two focus individuals in a group, but this difference itself has no direct effect on relative competitive ability. A subsequent empirical test of a novel mathematical tool reveals that there is no simple general rule for describing how relative competitive ability will change with group size, and that very specific knowledge of the system under study is needed in order to produce robust predictions. The relative abilities of individual chiclids to obtain food under scramble competition are shown to be highly repeatable between trials. However, when given a choice between two patches differing only in their temporal variability in input about an identical mean, an individual's rank based on intake in one patch was uncorrelated with either its uptake in the other patch or its intake in either of two different trial types. The basis for, and consequence of, this dependence of relative competitive ability on the context of the foraging situation are discussed. The general case (previously unexposed in the literature) where the effect of interference can vary between patches is examined. Simulations from an individual-based model reveal a decrease in the number of stable equilibrium distributions as the competitive advantage of the dominant phenotype declines in one patch, leading eventually to a single stable equilibrium, in which both phenotypes are found on both patches.

Why does it appall us if the CEO of a German prime bank lays off his employees despite sufficient revenue? Why do we feel contempt for Klaus Zumwinkel, a well-known tax evader? Why is Bill Gates admired for donating billions of dollars to a foundation? The answer to these questions appears to be remarkably simple: Because one seems wrong whereas the other right. More precisely, it is either morally right or morally wrong. This dissertation deals with emotions that arise when we assess peoples’ actions. Such emotions can be described as moral emotions. On the one hand, I am particularly interested in how these emotions are created. On the other hand, the consequences of identifying these emotions and therefore the function of moral emotions take on a significant role for me as well. I proceed on the assumption that these emotions have a mediating role for subsequent actions. Therefore, the key issues are why we experience the emotions we have and moreover, what is to be expected when we feel these emotions. Here, moral emotions are of major importance when transitioning from thinking to acting. Weiner (2006) and Rudolph, Roesch, Greitemeyer and Weiner (2004) previously described emotional reactions as mediating factors between cognitive processes (attributions) and subsequent behavior. Similar to this sequential model, moral emotions supposedly serve as a quick and efficient basis for decision-making regarding subsequent behavior as the heuristics advocated by Gigerenzer and Todd (1999). Here, moral emotions function as ‘heuristic cues’ that can channel our behavior. Even modern theories in computer and information science depict the human being as an “emotional machine” making use of emotionally driven programs in order to mediate between dynamic input factors from nature and adaptive output processes in terms of behavioral reactions. (Minsky, 2007) The methods of my research rely on a true role model: Charles Darwin. In his work “The Expression of the Emotions in Man and Animals” from 1872, Darwin also considered the question of what role emotions play and how they are created. Darwin (1872) proposed six potential methods to examine emotions in more detail (for an overview see Meyer, Schützwohl, & Reisenzein, 2008). Although Darwin mainly focused on the phylogenetic history and particularly dealt with the expression of mimicking as well as the congenital and inherited trigger conditions of emotional reactions, his findings and methods nevertheless were the role model for generations of emotion researchers and are still of great relevance (Izard, 1971, 1991, 1992; Lazarus, 1991a, 1991b, 1991c; Ortony, Clore, & Collins, 1988; Rudolph, Schulz, & Tscharaktschiew, 2013; Rudolph & Tscharaktschiew, 2014; Tomkins, 1963, 1962; Weiner, 2006). So far, Rudolph, Schulz and Tscharaktschiew (2013) have presented an empirically supported taxonomy of moral emotions and thereby have identified universally valid leading conditions of moral emotions. They are guided by attributional concepts as previously described by Heider (1958) in the context of his naïve analysis of action using forced-choice methods for selecting emotions with their subjects. Rudolph et al. (2013) divided moral emotions into emotions that assess one’s own actions (so-called actor emotions) or other people’s actions (so-called observer emotions). It becomes apparent that our moral identification of emotions depends on whether a) this action was considered as good or bad in terms of a moral standard, b) the goal of an action was or was not attained and c) the acting person made or did not make an effort in doing so. These dimensions are known as ought (a), goal-attainment (b) and effort (c). I am particularly interested in whether the dimensions discovered by Rudolph et al. (2013) will appear in autobiographical and free reports. Furthermore, I will examine more in depth the scenarios predicted by the theory and individual emotions in different test settings. All studies are conducted on an empirical basis using quantitative and qualitative methods that were previously applied by Darwin (1872) in modified form. First, I will examine whether the categories ought, goal-attainment and effort established by Rudolph et al. (2013) could be traced in recalled reports of emotional episodes using qualitative methods. Afterwards, extremely similar emotions will be distinguished in enhanced detail using a category system. Emotions such as anger, disgust and despite will be scrutinized in an experimental setting for the first time. It will be determined whether a sequential model of cognition emotion behavior already develops by the early stages using the complex emotions schadenfreude and sympathy with preschool children. For prisoners and people suffering from a personality disorder, the emotions of guilt and shame will be distinguished. In addition, the link to future behavior as well as neurological particularities of such groups of people will be taken into consideration. In my work, I will intensively scrutinize the category system assumed by Rudolph et al. (2013). Simultaneously, emotions that have been extremely similar or strongly connected thus far will be analyzed and described to a finer extent. Eventually, results will allow for a better understanding regarding the prediction of subsequent behavior
Wieso empört es uns, wenn der Vorstandsvorsitzende einer deutschen Großbank trotz sprudelnder Kassen Mitarbeiter entlässt? Wieso empfinden wir Verachtung für Klaus Zumwinkel, einen prominenten Steuersünder? Warum bewundern wir Bill Gates für seine Milliardenschenkung an eine Stiftung? Die Antwort auf diese Fragen scheint denkbar einfach: Weil das eine falsch, das andere dagegen richtig erscheint. Genauer gesagt: Es ist moralisch richtig oder moralisch falsch. In meiner Arbeit geht es um eben jene Emotionen, die entstehen, wenn Handlungen von Personen bewertet werden. Solche Emotionen kann man als moralische Emotionen bezeichnen. Dabei interessieren mich einerseits die Entstehung, andererseits die Konsequenzen eines solchen Emotionsempfindens und damit die Funktion der moralischen Emotionen. Ich gehe dabei davon aus, dass diese Emotionen einen vermittelnden Charakter für nachfolgende Handlungen haben. Die entscheidenden Fragen sind also: Warum haben wir die Emotionen, die wir haben? Und: Was ist zu erwarten, wenn wir diese Emotionen verspüren? Dabei nehmen die moralischen Emotionen eine Schlüsselrolle auf dem Weg vom Denken zum Handeln ein. Bereits Weiner (2006) oder Rudolph, Roesch, Greitemeyer und Weiner (2004) haben emotionale Reaktionen als vermittelnde Größen zwischen kognitiven Prozessen (Attributionen) und nachfolgendem Verhalten beschrieben. Ähnlich diesem Sequenzmodell sollten moralische Emotionen wie die von Gigerenzer und Todd (1999) propagierten Heuristiken als schnelle und sparsame Entscheidungsgrundlage für das nachfolgende Verhalten dienen. Bei einer solchen Betrachtung fungieren die moralischen Emotionen als ‚heuristic cues’, die unser Verhalten bahnen können. Sogar moderne Theorien im Fachbereich Informatik zeichnen das Bild vom Menschen als „emotionale Maschine“, die gefühlsgesteuerte Programme benutzt, um zwischen dynamischen Input-Größen aus der Natur und adaptiven Output-Prozessen im Sinne von Verhaltensreaktionen zu vermitteln (Minsky, 2007) Meine Untersuchungen folgen in der Auswahl der Methoden einem großen Vorbild: Charles Darwin. In seinem Werk „Der Ausdruck der Gemütsbewegungen bei dem Menschen und den Tieren“ (im englischen Original: The Expression of the Emotions in Man and Animals) geht Darwin (1872) ebenfalls den grundlegenden Fragen nach, welche Funktion Emotionen haben und wie sie entstehen. Dabei legt Darwin sechs mögliche Methoden vor, um sich mit Emotionen genauer zu beschäftigen (für einen Überblick siehe Meyer et al., 2008).Zwar liegt Darwins Fokus dabei eher auf der Stammesgeschichte und er beschäftigt sich vor allem mit dem mimischen Ausdruck sowie den angeborenen und vererbten Auslösebedingungen emotionaler Reaktionen. Dennoch waren und sind seine Erkenntnisse und die von ihm verwendeten Methoden das Vorbild für Generationen von Emotionsforschern (Izard, 1971, 1991, 1992; Lazarus, 1991a, 1991b, 1991c; Ortony et al., 1988; Rudolph et al., 2013; Rudolph & Tscharaktschiew, 2014; Tomkins, 1963, 1962; Weiner, 2006) Bisher haben Rudolph, Schulz und Tscharaktschiew (2013) eine empirisch gestützte Taxonomie moralischer Emotionen vorgelegt und damit allgemeingültige vorauslaufende Bedingungen moralischer Emotionen identifiziert. Sie orientieren sich dabei an attributionalen Konzepten, wie sie bereits Heider (1958) mit seiner naiven Handlungsanalyse beschreibt und benutzen dabei vor allem hypothetische Szenarien und vorgegebene Emotionswörter zur Untersuchung der Emotionen ihrer Probanden. Moralische Emotionen unterscheiden Rudolph et al. (2013), in solche Emotionen welche eigene Handlungen (so genannte Actor Emotionen) oder die Handlungen anderer (so genannte Observer Emotionen) bewerten. Es zeigt sich, dass unser moralisches Emotionsempfinden davon abhängt, ob diese Handlung a) bezogen auf einen moralischen Standard als gut oder schlecht gilt, b) das Ziel der Handlung erreicht wurde oder nicht und c) sich der Handelnde dabei angestrengt hat oder nicht. Diese Dimensionen bezeichnen wir als ought (a), goal-attainment (b) und effort (c). Mich interessiert in dieser Arbeit vor allem, ob sich die von Rudolph et al. (2013) gefundenen Dimensionen auch in autobiografischen Schilderungen und in freien Berichten wiederfinden. Darüber hinaus nehme ich die Voraussagen der Theorie und einzelne Emotionen in verschiedenen Untersuchungssettings genauer unter die Lupe. Alle Untersuchungen sind empirischer Natur und orientieren sich an den quantitativen und qualitativen Methoden, die in abgewandelter Form bereits Darwin (1872) benutzte. Als erstes prüfe ich anhand qualitativer Methoden, ob sich die von Rudolph et al. (2013) gefundenen Kategorien von ought, goal-attainment und effort auch in erinnerten Schilderungen emotionaler Episoden nachzeichnen lassen. Stark ähnliche Emotionen werden anschließend mithilfe eines Kategoriensystems noch besser unterschieden. Die Emotionen Ärger, Empörung und Verachtung werden in einem experimentellen Setting erstmals genauer unterschieden. Die Frage, ob sich ein Sequenzmodell von Kognition Emotion Verhalten bereits in frühen Entwicklungsstadien ausbildet, wird anhand der komplexen Emotionen Schadenfreude und Mitleid mit Vorschulkindern untersucht. Bei Strafgefangenen und Personen mit Persönlichkeitsstörungen werden die Emotionen Scham und Schuld näher unterschieden. Außerdem werden hier Zusammenhänge mit zukünftigem Verhalten sowie neurologischen Besonderheiten solcher Personengruppen betrachtet. Meine Arbeiten unterziehen einerseits das postulierte Kategoriensystem von Rudolph et al. (2013) einem harten Test. Gleichzeitig werden bisher stark ähnliche oder zusammenhängende Emotionen feiner analysiert und beschrieben. Schließlich ermöglichen die Ergebnisse ein besseres Verständnis für die Vorhersage von nachfolgendem Verhalten

La notion de besoin caractérise souvent une nécessité biologique, le strict minimum pour se nourrir et se loger. Les besoins ont pourtant souvent été définis comme relatifs et propres à une situation donnée. Les incitations culturelles et sociales tendent à fournir des motivations puissantes aux individus, les conduisant à prendre des décisions parfois à leur détriment au plus ou moins long-terme. Ces choix révèlent certains besoins allant au-delà de la seule survie. Ma thèse a pour objectif de mieux comprendre ces décisions en incluant des composants sociaux ou culturels à la théorie standard de la consommation. Elle contribue à faire le lien entre deux branches importantes de la littérature économique: l'analyse de la demande, et l'économie comportementale/sociale. Les différents chapitres répondent à des questions telles que : pourquoi les personnes souffrant de malnutrition dépensent une part significative de leur budget en biens ostentatoires (premier chapitre) ? Pourquoi des personnes différant seulement par le groupe social auquel elles appartiennent ne consomment pas les mêmes biens (deuxième chapitre) ? Les interactions sociales contribuent-elles à la persistance de goûts locaux (troisième chapitre) ? Et l'intégration commerciale contribue-t-elle à la convergence des goûts (quatrième chapitre) ? Ces sujets requièrent de considérer la signification sociale des choix de consommation, en plus de l'effet du revenu, des prix et de leur valeur fonctionnelle. En d'autres termes, ils requièrent de penser la consommation comme un langage
The notion of need often characterizes the strict minimum amount of food and shelter to survive. Needs have however recurrently been described as essentially relative and context-driven. Indeed, cultural and social incentives tend to provide powerful motivations for individuals to engage in choices sometimes detrimental to their short- or long-term fitness. These choices reveal certain needs which are beyond mere sustenance. My thesis aims at better understanding these decisions by including cultural and social components to a standard theory of consumption. By doing so, it contributes to bridge the gap between two important branches of the literature: demand analysis and behavioral/social economics. The different chapters adress questions such as: Why do malnourished people spend a significant portion of their budget on conspicuous goods (first chapter)? Why do people of different social groups choose to consume different types of goods, given similar prices, income and demographics (second chapter)? Do social interactions contribute to the persistence of localized tastes (third chapter)? And does market integration contribute to taste convergence (fourth chapter)? These topics require to take into account the social meaning of consumption choices, aside from income, prices and functionality. In other words, they require to consider consumption as a language

Social interactions have been the focus of social science research for a century, but their study has recently been revolutionized by novel data sources and by methods from computer science, network science, and complex systems science. The study of social interactions is crucial for understanding complex societal behaviours. Social interactions are naturally represented as networks, which have emerged as a unifying mathematical language to understand structural and dynamical aspects of socio-technical systems. Networks are, however, highly dimensional objects, especially when considering the scales of real-world systems and the need to model the temporal dimension. Hence the study of empirical data from social systems is challenging both from a conceptual and a computational standpoint. A possible approach to tackling such a challenge is to use dimensionality reduction techniques that represent network entities in a low-dimensional feature space, preserving some desired properties of the original data. Low-dimensional vector space representations, also known as network embeddings, have been extensively studied, also as a way to feed network data to machine learning algorithms. Network embeddings were initially developed for static networks and then extended to incorporate temporal network data. We focus on dimensionality reduction techniques for time-resolved social interaction data modelled as temporal networks. We introduce a novel embedding technique that models the temporal and structural similarities of events rather than nodes. Using empirical data on social interactions, we show that this representation captures information relevant for the study of dynamical processes unfolding over the network, such as epidemic spreading. We then turn to another large-scale dataset on social interactions: a popular Web-based crowdfunding platform. We show that tensor-based representations of the data and dimensionality reduction techniques such as tensor factorization allow us to uncover the structural and temporal aspects of the system and to relate them to geographic and temporal activity patterns.

This thesis develops methods for social signal reconstruction—in particular, we measure human motion during social interactions. Compared to other work in this space, we aim to measure the entire body, from the overall body pose to subtle hand gestures and facial expressions. The key to achieving this without placing markers, instrumentation, or other restrictions on participants is the Panoptic Studio, a massively multi-view capture system which allows us to obtain 3D reconstructions of room-sized scenes. To measure the position of joints and other landmarks on the human body, we combine the output of 2D keypoint detectors across multiple views and triangulate them in 3D. We develop a semi-supervised training procedure, multi-view bootstrapping, which uses 3D triangulation to generate training data for keypoint detectors. We use this technique to train fine-grained 2D keypoint detectors for landmarks on the hands and face, allowing us to measure these two important sources of social signals. To model human motion data, we present the Kronecker Markov Random Field (KMRF) model for keypoint representations of the face and body. We show that most of the covariance in natural body motions corresponds to a specific set of spatiotemporal dependencies which result in a Kronecker or matrix normal distribution over spatiotemporal data, and we derive associated inference procedures that do not require training sequences. This statistical model can be used to infer complete sequences from partial observations and unifies linear shape and trajectory models of prior art into a probabilistic shape-trajectory distribution that has the individual models as its marginals. Finally, we demonstrate full-body motion reconstructions by using the KMRF model to combine the various measurements obtained from the Panoptic Studio. We capture a dataset of groups of people engaged in social games and fit mesh models of the body, face, and hands—a representation that encodes many of the social signals that characterize an interaction and can be used for analysis, modeling, and animation.

La recherche proposée s'intéresse au développement d'un modèle d'interaction sociale capable de prendre en compte, en univers virtuel collaboratif, une partie de la dimension émotionnelle et sociale des interactions humaines.
Dans notre approche, chaque utilisateur contrôle son propre avatar (représentation de l'utilisateur dans l'environnement virtuel) et peut prendre des décisions selon ses propres perceptions, son expertise et historique. La problématique de recherche devient donc d'offrir une solution pour maintenir un contexte d'interaction 'riche' lors de la collaboration.
Nous proposons des solutions qui permettent d'enrichir l'interaction sociale en univers virtuel. D'une part, l'interface proposée permet aux interactants d'exploiter leurs références indexicales (par exemple pointer de la main des objets de l'univers, orienter le regard vers une direction, etc.). D'autre part, notre modèle d'interaction sociale permet de produire automatiquement des comportements chez les avatars qui soient pertinents par rapport au contexte de l'interaction (par exemple distribuer le regard vers ses interlocuteurs, regarder les autres avatars en marchant, effectuer des expressions gestuelles en parlant, etc.).
Nous proposons également un modèle émotionnel pour simuler les états internes des personnages virtuels en interaction.
Ces modèles s'intègrent dans une architecture multi-agents capable de fusionner de façon 'réaliste' les actions intentionnelles décidées par l'acteur humain et les comportements non-intentionnels (produits par le modèle d'interaction sociale) comme les gestes, postures, expressions émotionnelles qui dépendent du contexte dans lequel évoluent les avatars.

The main purpose of this study was to investigate the pattern of relationships among three constructs: neighbourhood socio-physical environment, children’s social interactions and their social capital. The research also explored how country of residence, gender, social-economic status and ethnic background relate to the pattern of relationships. In addition, this study was based upon and tried to corroborate the interactional—constructivist world View and the theory of social capital. Three bodies of research literature formed the background of the current study: (1) the interactional—constructivist world View was the framework that shed lights on the research questions and the research methods; (2) the theory of social capital provided the basis for developing the scale of children’s social capital; and (3) previous studies on children and their neighbourhood socio-physical environment helped to develop the scale of neighbourhood socio—physical environment. The main research question was: what is the pattern of relationships among children’s assessment of their neighbourhood socio-physical environment, social interactions and social capital? Other research questions investigated the differences between children in Beijing and Sydney, boys and girls, and differences due to family’s socio-economic background and ethnic background. This research was carried out in two phases. Phase I included the qualitative studies to develop a scale of neighbourhood socio-physical environment, a scale of children’s social interactions and a scale of children’s social capital. Phase II was a cross-national survey that used these three scales to collect information from high school students in Beijing and Sydney. During phase I, qualitative techniques such as interviews, walking tours and photographs were used to collect information from the respondents. During phase II, the investigator used a self-administered questionnaire to collect data from 166 Australian students and 234 Chinese students. Exploratory factor analysis, analysis of variance and structural equation modeling were used to analyse the main study data. The main finding of the current study was that there were strong and significant correlations between each pair of the three constructs. Children’s assessment of their neighbourhood socio-physical environment was found to be positively related to their social interactions and social capital, which indicated that children who live in better neighbourhoods had more social interactions and larger volumes of social capital. Strong positive relationship was also found between children’s social interactions and social capital, which indicated that better—connected children interacted with their friends more. In addition, significant differences between students in Beijing and Sydney, differences due to gender, socio-economic status and ethnic background were revealed from the data. For example, students in Sydney rated their socio-physical environment higher than students in Beijing; girls assessed themselves as having smaller volumes of social capital than boys; children from better educated families had more social capital; and Australian children with European backgrounds exercised more often than Australian children from other ethnic backgrounds. This study has two theoretical implications. Firstly, as the findings of this research supported the main research hypothesis, this study corroborated the interactional—constructivist world view. Secondly, as the data supported the ecological model of children’s social capital, this study corroborated the theory of social capital. The results of this study provide important information to planners, designers, and policy makers: we can improve the socio-physical environments of neighbourhoods to support children’s social development. This study also provides information to help parents choose child-friendly neighbourhoods to live. It also suggests that parents should encourage their children to interact with friends more, so that their children may build wider and stronger friendship networks to increase their social capital.

Interactions are what gives us the knowledge of the world around us. Interactions on all levels may fundamentally be seen as an exchange of information and a possible response of the same. Whether it is an electron in an electrical field or a handsome dude in a bar responding to a flirtation---interactions make things happen. In this sense we can see that objects without the capability of interacting with each other also are invisible to each other. Chains of pairwise interacting entities can serve as mediators of indirect interactions between objects. Nonetheless, in the limit of no interactions, we get into a philosophical debate whether we actually may consider anything to exist since it can not be detected in any way. Interactions between matter tend to be organized and show a hierarchical structure in which smaller sub-systems can be seen as parts of a bigger system, which in turn might be a smaller part of an even bigger system. This is reflected by the fact that we have sciences that successfully study specific interactions between objects or matter---physics, chemistry, biology, ecology, sociology,... What happens in a situation where all length scales are important? How does the structure of the underlying network of interactions affect the dynamical properties of a system? What network structures do we find and how are they created? This thesis is a physicist's view of collective dynamics, from superconductors to social systems and navigation in city street networks.

This thesis consists of three papers in the broad field of Applied Economics. I focus on three "soft factors", namely, face-to-face communication, brief social interactions and information updates. I study on how they affect individual and organisational outcomes using different natural experiments. The first chapter provides causal evidence on how the ability to communicate face-to-face (in addition to electronic communication) can increase organisational performance. The study exploits a natural experiment within a large organisation where workers must communicate electronically with their teammates. A computerized system allocates the tasks to workers creating exogenous variation in the co-location of teammates. Workers who share the same room, can also communicate in person. The main findings are that face-to-face communication increases productivity and that this effect significantly varies across tasks, team characteristics and working environments. In the second chapter I construct a novel dataset of immigrants and ships arrived to the US in the early 20th century to study the effects of brief social interactions and their persistence over time. The chapter shows that individuals travelling (during few days) with shipmates that have better connections in the US, have higher quality jobs. Several findings are consistent with the mechanism whereby individuals get information or access to job opportunities from their shipmates. The study highlights the importance of social interactions with unknown individuals during critical life junctures. It also suggests that they are more relevant for individuals with poor access to information or weak social networks. The third chapter shows that executions cause a local and temporary reduction in serious violent crime. The interpretation of this result follows from a theoretical framework connecting information updates with the increasing 'awareness' of individuals about the consequences of crime. Consistently with the predictions of the model, the study finds that effects are stronger when media attention is high and lower in places with high propensity to apply the death penalty.

This thesis examines the underlying cause of social stigma towards people living with HIV, and the extent to which it discourages HIV testing and treatment. We use a discrete choice model to describe a person’s decision to seek treatment for HIV (antiretroviral therapy or ART), and estimate the social cost of seeking treatment using administrative health records from southern Malawi. We show that seeking ART at a clinic where many other community members are present carries a significant cost, even after taking into account clinic quality and location. We investigate the theoretical effects of policy interventions designed to reduce stigma and other barriers to care, and demonstrate important complementarities between such policies. We next evaluate a cluster-randomized information experiment in Zomba, Malawi designed to correct a common misconception: most do not know that ART drugs have a public benefit, that is, the medication prevents HIV transmission between sexual partners. We microfound HIV stigma as sexual discrimination between sexual partners, and model the decision to seek an HIV test (and then, if required, medical treatment) as a signal of infection. We show, theoretically and empirically, that the randomized information intervention reduces this type of stigma and significantly increases the rate of HIV testing. The results demonstrate that social stigma is an important barrier to HIV testing and treatment, that stigma can be due to rational behavior by a misinformed public, and that providing new information can be an effective way to mitigate its effects.

Vocal interactions, such as call exchanges or choruses, are common behaviours in animals and their function has been often linked to social bonding. In this study, I examined the relationship between two types of vocal behaviour common in chimpanzees, pant hoot chorusing and food calling, and social bonds between males. The results of this study, which was conducted on the Kanyawara community of chimpanzees (Pan troglodytes schweinfurthii) in the Kibale National Park, Uganda, show that both pant hoot choruses and food-associated calls reliably reflect social bonds between males. For example, males were more likely to join in another male’s pant hoot when a well affiliated male was calling. Males, irrespective of the long-term affiliation status between them, were also more likely to be involved in grooming or form coalitions on days when they chorused together, suggesting that chorusing is also a flexible bonding behaviour operating on a short-term basis. Males were also considerably more likely to produce food-associated calls when feeding in close proximity to well affiliated males than to less affiliated ones or females. Importantly, a male feeding partner was more likely to remain with the focal until the end of a feeding bout if the focal food called at the onset of this bout, suggesting that these vocalisations mediate feeding decisions between affiliated males. The results of my study suggest that these two types of vocalisations play important functions in chimpanzee fission-fusion societies. Pant hoot chorusing, for example, might facilitate the occurrence of other affiliative interactions between individuals who are not necessarily long-term preferred social partners. Food-associated calls, on the other hand, might facilitate anticipation of each feeding decision which in turn facilitates individuals remaining in proximity or in the same party. Both these types of vocalisations, therefore, might mitigate the costs of living in unstable societies formed by these primates.

Young children’s peer interactions involve their use of interactional resources to organise, manage and participate in their social worlds. Investigation of children’s employment of interactional resources highlights how children participate in peer interaction and their social orders, providing insight into their active construction and management of their social worlds. Frequently, these interactions are described by adults as ‘play’. The term play is often used to describe children’s activities in early childhood education, and constructed in three main ways: as educative, as enjoyable, and as an activity of children. Play in educational settings is often constructed, and informed by, adult agendas such as learning and is often part of the educational routine. This study shows how children work with a different set of agendas to those routinely ascribed by adults, as they actively engage with local education orders, and use play for their own purposes as they construct their own social orders. By examining children’s peer interactions, and not describing these activities as play, the focus becomes the construction and organisation of their social worlds. In so doing, this study investigates some interactional resources that children draw upon to manage their social orders and organise their peer interactions. This study was conducted within an Australian, non-government elementary school. The participants were children in a preparatory year classroom (children aged 4 – 6 years). Over a one month period, children’s naturally occurring peer interactions within ‘free play’ were video-recorded. Selected video-recorded episodes were transcribed and analysed, using the approaches of ethnomethodology, conversation analysis and membership categorization analysis. These methodologies focus on everyday, naturalistic data, examining how participants orient to and produce social action. The focus is on the members’ perspectives, that of the children themselves, as they interact. Ethnomethodology, conversation analysis and membership categorization analysis allow for in-depth examination of talk and action, and are used in this study to provide a detailed account of the children’s interactional strategies. Analysis focused on features of children’s situated peer interaction, identifying three interactional resources upon which the children drew as they constructed, maintained, and transformed their social orders. The interactional resources included: justification; category work, in particular the category of mother; and the pretend formulation of place. The children used these interactional resources as a means of managing peer participation within interactions. First, the children used justification to provide reasons for their actions and to support their positions. Justifications built and reinforced individual children’s status, contributing to the social organisation of their peer group. Second, the children negotiated and oriented to categories within the pretend frame of ‘families’. The children’s talk and actions jointly-constructed the mother category as authoritative, enabling the child, within the category of mother, to effectively organise the interaction. Third, pretense was used by the children to negotiate and describe places, thus enabling them to effectively manage peer activity within these places. For a successful formulation of a place as something other than it actually was, the children had to work to produce shared understandings of the place. Examining instances of pretense demonstrated the highly collaborative nature of the children’s peer interactions. The study contributes to sociological understandings of childhood. By analysing situated episodes of children’s peer interaction, this study contributes empirical work to the sociology of childhood and insight into the interactional work of children organising their social worlds. It does this by closely analysing social interactions, as they unfold, among children. This study also makes a methodological contribution, using ethnomethodology, conversation analysis, and membership categorization analysis in conjunction to analyse children’s peer interactions in an early childhood setting. In so doing, the study provides alternative ways for educators to understand children’s interactions. For example, adult educational agendas, such as the educative value of play, can be applied to examine children’s family play, highlighting the learning opportunities provided through pretend role play, or indicating children’s understanding of adult roles. Alternatively, the children’s interaction could be subjected to fine-grained analysis to explicate how children construct shared understandings of the category of mother and use it to organise their interaction. Rather than examining the interaction to discern what children are learning, the interaction is examined with a focus on how children are accomplishing everyday social practices. Close analysis of children’s everyday peer interaction enables the complex interactional work of managing, and participating in, social order within an early childhood setting to be explicated. This offers educators insight into children’s social worlds, described not as play, but as the construction and negotiation of social order.

Young children’s peer interactions involve their use of interactional resources to organise, manage and participate in their social worlds. Investigation of children’s employment of interactional resources highlights how children participate in peer interaction and their social orders, providing insight into their active construction and management of their social worlds. Frequently, these interactions are described by adults as ‘play’. The term play is often used to describe children’s activities in early childhood education, and constructed in three main ways: as educative, as enjoyable, and as an activity of children. Play in educational settings is often constructed, and informed by, adult agendas such as learning and is often part of the educational routine. This study shows how children work with a different set of agendas to those routinely ascribed by adults, as they actively engage with local education orders, and use play for their own purposes as they construct their own social orders. By examining children’s peer interactions, and not describing these activities as play, the focus becomes the construction and organisation of their social worlds. In so doing, this study investigates some interactional resources that children draw upon to manage their social orders and organise their peer interactions. This study was conducted within an Australian, non-government elementary school. The participants were children in a preparatory year classroom (children aged 4 – 6 years). Over a one month period, children’s naturally occurring peer interactions within ‘free play’ were video-recorded. Selected video-recorded episodes were transcribed and analysed, using the approaches of ethnomethodology, conversation analysis and membership categorization analysis. These methodologies focus on everyday, naturalistic data, examining how participants orient to and produce social action. The focus is on the members’ perspectives, that of the children themselves, as they interact. Ethnomethodology, conversation analysis and membership categorization analysis allow for in-depth examination of talk and action, and are used in this study to provide a detailed account of the children’s interactional strategies. Analysis focused on features of children’s situated peer interaction, identifying three interactional resources upon which the children drew as they constructed, maintained, and transformed their social orders. The interactional resources included: justification; category work, in particular the category of mother; and the pretend formulation of place. The children used these interactional resources as a means of managing peer participation within interactions. First, the children used justification to provide reasons for their actions and to support their positions. Justifications built and reinforced individual children’s status, contributing to the social organisation of their peer group. Second, the children negotiated and oriented to categories within the pretend frame of ‘families’. The children’s talk and actions jointly-constructed the mother category as authoritative, enabling the child, within the category of mother, to effectively organise the interaction. Third, pretense was used by the children to negotiate and describe places, thus enabling them to effectively manage peer activity within these places. For a successful formulation of a place as something other than it actually was, the children had to work to produce shared understandings of the place. Examining instances of pretense demonstrated the highly collaborative nature of the children’s peer interactions. The study contributes to sociological understandings of childhood. By analysing situated episodes of children’s peer interaction, this study contributes empirical work to the sociology of childhood and insight into the interactional work of children organising their social worlds. It does this by closely analysing social interactions, as they unfold, among children. This study also makes a methodological contribution, using ethnomethodology, conversation analysis, and membership categorization analysis in conjunction to analyse children’s peer interactions in an early childhood setting. In so doing, the study provides alternative ways for educators to understand children’s interactions. For example, adult educational agendas, such as the educative value of play, can be applied to examine children’s family play, highlighting the learning opportunities provided through pretend role play, or indicating children’s understanding of adult roles. Alternatively, the children’s interaction could be subjected to fine-grained analysis to explicate how children construct shared understandings of the category of mother and use it to organise their interaction. Rather than examining the interaction to discern what children are learning, the interaction is examined with a focus on how children are accomplishing everyday social practices. Close analysis of children’s everyday peer interaction enables the complex interactional work of managing, and participating in, social order within an early childhood setting to be explicated. This offers educators insight into children’s social worlds, described not as play, but as the construction and negotiation of social order.

Une interaction sociale désigne toute action réciproque entre deux ou plusieurs individus, au cours de laquelle des informations sont partagées sans "médiation technologique". Cette interaction, importante dans la socialisation de l'individu et les compétences qu'il acquiert au cours de sa vie, constitue un objet d'étude pour différentes disciplines (sociologie, psychologie, médecine, etc.). Dans le contexte de tests et d'études observationnelles, de multiples mécanismes sont utilisés pour étudier ces interactions tels que les questionnaires, l'observation directe des événements et leur analyse par des opérateurs humains, ou l'observation et l'analyse à posteriori des événements enregistrés par des spécialistes (psychologues, sociologues, médecins, etc.). Cependant, de tels mécanismes sont coûteux en termes de temps de traitement, ils nécessitent un niveau élevé d'attention pour analyser simultanément plusieurs descripteurs, ils sont dépendants de l'opérateur (subjectivité de l'analyse) et ne peuvent viser qu'une facette de l'interaction. Pour faire face aux problèmes susmentionnés, il peut donc s'avérer utile d'automatiser le processus d'analyse de l'interaction sociale. Il s'agit donc de combler le fossé entre les processus d'analyse des interactions sociales basés sur l'homme et ceux basés sur la machine. Nous proposons donc une approche holistique qui intègre des signaux hétérogènes multimodaux et des informations contextuelles (données "exogènes" complémentaires) de manière dynamique et optionnelle en fonction de leur disponibilité ou non. Une telle approche permet l'analyse de plusieurs "signaux" en parallèle (où les humains ne peuvent se concentrer que sur un seul). Cette analyse peut être encore enrichie à partir de données liées au contexte de la scène (lieu, date, type de musique, description de l'événement, etc.) ou liées aux individus (nom, âge, sexe, données extraites de leurs réseaux sociaux, etc.) Les informations contextuelles enrichissent la modélisation des métadonnées extraites et leur donnent une dimension plus "sémantique". La gestion de cette hétérogénéité est une étape essentielle pour la mise en œuvre d'une approche holistique. L'automatisation de la capture et de l'observation " in vivo " sans scénarios prédéfinis lève des verrous liés à i) la protection de la vie privée et à la sécurité ; ii) l'hétérogénéité des données ; et iii) leur volume. Par conséquent, dans le cadre de l'approche holistique, nous proposons (1) un modèle de données complet préservant la vie privée qui garantit le découplage entre les méthodes d'extraction des métadonnées et d'analyse des interactions sociales ;[...]
Social interaction refers to any interaction between two or more individuals, in which information sharing is carried out without any mediating technology. This interaction is a significant part of individual socialization and experience gaining throughout one's lifetime. It is interesting for different disciplines (sociology, psychology, medicine, etc.). In the context of testing and observational studies, multiple mechanisms are used to study these interactions such as questionnaires, direct observation and analysis of events by human operators, or a posteriori observation and analysis of recorded events by specialists (psychologists, sociologists, doctors, etc.). However, such mechanisms are expensive in terms of processing time. They require a high level of attention to analyzing several cues simultaneously. They are dependent on the operator (subjectivity of the analysis) and can only target one side of the interaction. In order to face the aforementioned issues, the need to automatize the social interaction analysis process is highlighted. So, it is a question of bridging the gap between human-based and machine-based social interaction analysis processes. Therefore, we propose a holistic approach that integrates multimodal heterogeneous cues and contextual information (complementary "exogenous" data) dynamically and optionally according to their availability or not. Such an approach allows the analysis of multi "signals" in parallel (where humans are able only to focus on one). This analysis can be further enriched from data related to the context of the scene (location, date, type of music, event description, etc.) or related to individuals (name, age, gender, data extracted from their social networks, etc.). The contextual information enriches the modeling of extracted metadata and gives them a more "semantic" dimension. Managing this heterogeneity is an essential step for implementing a holistic approach. The automation of " in vivo " capturing and observation using non-intrusive devices without predefined scenarios introduces various issues that are related to data (i) privacy and security; (ii) heterogeneity; and (iii) volume. Hence, within the holistic approach we propose (1) a privacy-preserving comprehensive data model that grants decoupling between metadata extraction and social interaction analysis methods; (2) geometric non-intrusive eye contact detection method; and (3) French food classification deep model to extract information from the video content.[...]

Du recrutement à l'apprentissage, les relations entre employeurs et employés sont caractérisées par un important degré d'hétérogénéité. Cette thèse propose de reconsidérer ces étapes clés de la relation d'emploi, à travers des modèles théoriques, en tenant compte de l'hétérogénéité des travailleurs et des employeurs. En premier lieu, l'observabilité imparfaite des candidats à l'emploi conduit les employeurs à investir dans le processus de recrutement pour limiter les risques de sélection adverse. Le choix de la méthode de recherche se révèle alors déterminant, les canaux de recrutement étant analysés comme des filtres permettant de discriminer les candidats. En deuxième lieu, la prépondérance des méthodes de recrutement informelles conduit à mettre l'accent sur l'hétérogénéité des employeurs dans leur capacité à mobiliser leur réseau personnel pour recruter. Nous explorons ainsi le fonctionnement du « marché des réseaux sociaux » en analysant les méthodes de cooptation traditionnelles (réseaux personnel ou d'anciens étudiants) et en intégrant les nouvelles pratiques d'e-cooptation observées. En dernier lieu, l'issue du processus de recrutement implique forcément une nouvelle forme d'hétérogénéité. Les nouveaux recrutés ne détenant pas les compétences spécifiques à la firme, les employeurs doivent trouver les moyens de susciter une transmission des compétences à même de résorber l'hétérogénéité. Nous montrons finalement que les inefficiences générées par l'hétérogénéité de l'offre et la demande de travail peuvent être dépassées par le rôle des intermédiaires sur ce marché, par des politiques publiques adaptées et par une réorganisation des travailleurs au sein des firmes
From recruitment to learning, relationships between employers and employees are characterized by a large degree of heterogeneity. This thesis aims at analyzing such key steps of the employment relationship, through the development of theoretical models, stressing both workers and employers' heterogeneity. First, the unobservable characteristics of applicants lead the employer to invest in recruitment activities, in order to prevent any risk of adverse selection. Assuming that hiring channels is a mean of screening applicants, the choice of the hiring method particularly matters. Second, as a result of the increasing role of informal recruitment, the thesis focuses on the heterogeneity of employers towards their ability to recruit through their personal networks. We thus explore the “social networks market” by analyzing traditional referral methods (personal and alumni networks) and integrating the new electronic ways to get reliable referrals. Last, once the recruitment process ends up, a new kind of heterogeneity emerges among workers. Since new hires do not hold firm specific competences, employers should find a way to induce an efficient competences transmission able to reduce the heterogeneity between workers. The thesis finally shows that inefficiencies resulting from the heterogeneity on the labor supply and demand sides can be overcome by the role of intermediaries on the market, by the implementation of adapted public policies and by the reorganization of workers inside firms

With the advent of computer games, the Human Computer Interaction (HCI) community has begun studying games, often with the intention of uncovering useful information to inform the design of work-based software. However, most HCI research on computer games focuses on the use of game technologies, often overlooking the fairly large amount of classic game literature. Despite the potential importance of computer game studies in HCI, there is a lack of frameworks that could guide such studies especially with regard to sociability. I believe that sociability is one of the most important criteria game developers may want to apply to game design as computer games are becoming more socialoriented due to the inception of the Internet. Therefore, the main aim of the thesis is to develop a play activity framework with an emphasis on social interactions. To achieve this, first, a comprehensive body of game literature was reviewed as a step to provide a solid foundation for the construction of the framework. Through the extensive review of literature, I chose Activity Theory as the foundation for the framework development. In order to demonstrate the applicability of Activity Theory in analysing computer-mediated social interactions, an exploratory study of online activities in a game community was conducted. Then, two studies were undertaken to formulate the framework by modelling play activities in the social game context. The first study was centred on the individual and collective play activities that take place within the game virtual world. The second study focused on games as a whole participatory culture, in which playing games is not just confined to within the game space but also includes other playful activities governed by norms and specific identities around the game. Through these studies, a play activity framework consisting of three play mode/s was developed: intrinsic, reflective and expansive play models, which are inter-related. The framework provides a vocabulary to describe the component, the motivation and the process of game play. The framework was then operationalised into methodological guidelines with a set of heuristic questions grouped into different categories. The guidelines were applied to analyse two issues, namely community building and social learning, in a Massively Multi-player Online Game (MMOG). As a conclusion, the framework has expanded conventional game studies by emphasising the socio-cultural context. It provides a different perspective on analysing computer games particularly the social aspects of gaming. Game researchers could use the framework to investigate play activities within and beyond the game and how they are related. The framework offers a theoretical explanation of various social activities observed in computer games. Finally, the methodological guidelines derived from the framework are useful as they give directions to analyse play activities particularly social interactions and game communities.

In the simulation of human crowd behavior including evacuation planning, transportation management, and safety engineering in architecture design, the development of pedestrian model for higher behavior fidelity is an important task. To construct plausible facsimiles of real crowd movements, simulations should exhibit human behaviors for navigation, pedestrian decision-making, and social behaviors such as grouping and crowding. The research field is quite mature in some sense, with a large number of approaches that have been proposed to path finding, collision avoidance, and visually pleasing steering behaviors of virtual humans. However, there is still a clear disparity between the variety of approaches and the quality of crowd behaviors in simulations.

Many social science field studies inform us that crowds are typically composed of multiple social groups (James, 1953; Coleman and James, 1961; Aveni, 1977). These observations indicate that one component of the complexity of crowd dynamics emerges from the presence of various patterns of social interactions within small groups that make up the crowd. Hence, realism in a crowd simulation may be enhanced when virtual characters are organized in multiple social groups, and exhibit human-like coordination behaviors.

Motivated by the need for modeling groups in a crowd, we present a multi-agent model for large crowd simulations that incorporates socially plausible group behaviors. A computational model for multi-agent coordination and interaction informed by well- established Common Ground theory (Clark, 1996; Clark and Brennan, 1991) is proposed. In our approach, the task of navigation in a group is viewed as performing a joint activity which requires maintaining a state of common ground among group members regarding walking strategies and route choices. That is, group members communicate with, and adapt their behaviors to each other in order to maintain group cohesiveness while walking. In the course of interaction, an agent may present gestures or other behavioral cues according to its communicative purpose. It also considers the spatiotemporal conditions of the agent-group\'s environment in which the agent interacts when selecting a kind of motions.

With the incorporation of our agent model, we provide a unified framework for crowd simulation and animation which accommodates high-level socially-aware behavioral realism of animated characters. The communicative purpose and motion selection of agents are consistently carried through from simulation to animation, and a resulted sequence of animated character behaviors forms not merely a chain of reactive or random gestures but a socially meaningful interactions.

We conducted several experiments in order to investigate the impact of our social group
interaction model in crowd simulation and animation. By showing that group communicative behaviors have a substantial influence on the overall distribution of a crowd, we demonstrate the importance of incorporating a model of social group interaction into multi-agent simulations of large crowd behaviors. With a series of perceptual user studies, we show that our model produces more believable behaviors of animated characters from the viewpoint of human observers.

Ph. D.

Social interaction – is a form of social connections that is realized in the exchange of activities, information, experience, abilities, skills, and in the mutual influence of people.We believe that these skills need to be learnt in higher education establishment, because during practice we understand more how to behave in any situation. And also improve the acquired knowledge in practice.
Social interaction – is a form of social connections that is realized in the exchange of activities, information, experience, abilities, skills, and in the mutual influence of people.We believe that these skills need to be learnt in higher education establishment, because during practice we understand more how to behave in any situation. And also improve the acquired knowledge in practice.

Social interaction – is a form of social connections that is realized in the exchange of activities, information, experience, abilities, skills, and in the mutual influence of people.We believe that these skills need to be learnt in higher education establishment, because during practice we understand more how to behave in any situation. And also improve the acquired knowledge in practice.
Social interaction – is a form of social connections that is realized in the exchange of activities, information, experience, abilities, skills, and in the mutual influence of people.We believe that these skills need to be learnt in higher education establishment, because during practice we understand more how to behave in any situation. And also improve the acquired knowledge in practice.

The complex social relationships in society can be understood as a network. In recent years, complex networks have given researchers a more accurate picture of social interactions than aggregation models such as compartmental models had hitherto provided. Compartmental models which collect individuals into population classes based on infection state, for instance, had left out local interactions that could be important for understanding social relationships and attendant phenomena such as epidemics, rumors, etc., in the society. Topics of modeling for complex networks have included the dynamics of social relationships and how they affect disease and opinion spread. Different types of relationships, such as friendly or unfriendly, have been considered. In this dissertation we study social network models in which interactions can be beneficial or detrimental to the parties involved. Motivated by HIV, in which a person's infection status is not readily known to others, we implement a model where individual decisions may affect the disease transmission. Individuals in such a situation may use information about each other's behavior such as the number of connections (degree) to form a risk-benefit assessment for whether to engage in a relationship. We study this model for a single benefit case, and then a multiple benefit case. We also investigate the case where offspring may inherit the benefit of their parents to determine how this affects disease transmission. We find that human behavior and individual differences can affect infection transmission and that adaptation in behavior can mitigate the disease prevalence. Further, we study mutual ratings in a growing social network. We use two types of links, positive for favorable ratings between two nodes, and negative otherwise. We model a social network where positive and negative ratings are assigned preferentially based on existing positive and negative links. Extending previous ideas and analytical methods in the growing networks literature, we study the resulting network structure. For one of the preferential attachment mechanisms we consider, we derive an analytical expression for the joint distribution of positive and negative degrees in the limit of large networks. The insights gleaned in these studies will inform potential investigations of the impact of personal decisions on transmission of STIs such as HIV, and empirical studies of the evolution of friend-foe relationships on online social networks that have mechanisms for users to note or express opinions about other users or the contributions they made.

Despite high levels of exposure, firefighter posttraumatic stress disorder (PTSD) rates are unclear. Likewise, questions remain regarding how social interactions and beliefs about emotion might interact to influence PTSD in firefighters. In this study, U.S. urban firefighters (N = 225) completed measures of social support, negative social interactions, and fear of emotion which were then used via regression analyses to predict PTSD symptoms. Each independent variable predicted PTSD beyond variance accounted for by demographic variables. Additionally, fear of emotion emerged as the strongest individual predictor of PTSD and a moderator of the relation between social interactions and PTSD symptoms. These findings emphasize the importance of beliefs about emotion; both in how these beliefs might influence the expression of PTSD symptoms, and in how the social networks of trauma survivors might buffer distress.

Olfactory signals are generally regarded as the oldest and most widespread form of communication across taxa. They can play an important role in the mediation of social interactions, reproductive status and warning of danger, whilst also signalling more fixed genetic factors such as the major histocompatability complex, which is linked to inbreeding avoidance. Little is known of the role odour might play in humans, although there is some indication that humans may be influenced by a family of androgen steroids called the 16-androstenes, produced in axillary odour. Here I aim to identify the role of androstene compounds in humans, as well as body odour as a whole, using two theoretical frameworks based on intersexual and intrasexual signalling. Evidence is found to suggest androstadienone (“AND”, a putative male pheromone) and male odour (a composite sample of axillary sweat) may be having a suppressive effect on males. Men exposed to AND feel less attractive and potentially behave less attractive too, as judged by third-party raters. In a physical performance test, male odour is found to have a similar suppressing effect, with exposure being linked to decreased men’s performance in a cycling time trial and aspects of a 30-second cycling sprint test. In contrast, women exhibited stimulatory responses to the male odour, not AND. An analytical assessment of male odour was carried out, in an effort to link androstene profiles to aspects of phenotypic quality and socially relevant traits. Cluster analysis revealed that men’s odour profiles fell into two groups, which in turn could be explained by relationship status. In essence, single men have different compounds in their odour to men in a relationship. Furthermore, the odour of single men appears to be preferred by women. Exposure to solutions based on these two groups had sex specific effects on the receiver. In conclusion, the results highlight the novel possibility of human male intra-sexual signalling, whilst providing the only empirical evidence of odour chemistry links with social function in humans; paving the way for further investigations in this field.

This Doctoral thesis is divided in three chapters, each corresponding to a self-consistent paper in which, even if with different focus and methodology, the aim is to understand the economics beyond social interactions. In particular I investigate how different strategic, informational or social environment affect the diffusion and evolution of agents’ beliefs, preferences and norms. The first chapter On the Interplay Between Norms and Strategic Environments” is a joint work with Pietro Dindo and we study the role of different strategic environment for the dynamics of norms in a heterogeneous population divided into two cultural groups. In the second chapter "Cultural Transmission with Incomplete Information: Parental Self-Efficacy and Group Misrepresentation” a joint work with Fabrizio Panebianco, we analyze, using the solution concept of self-confirming equilibrium, a cultural transmission model where parents have incomplete information about the the social structure and the efficacy of their vertical transmission efforts. The last chapter ”Non-Bayesian Social Learning and the Spread of Misinformation in Networks” studies learning in a setting where agents receive each period independent noisy signals about the true state of the world and then communicate in a network where there are stubborn agents who spread misinformation. The first chapter On the Interplay Between Norms and Strategic Environments” is a joint work with Pietro Dindo and we study the role of different strategic environment for the dynamics of norms in a heterogeneous population divided into two cultural groups. In the second chapter "Perceived Group Under-Representation. Cultural Transmission with Incomplete Information” a joint work with Fabrizio Panebianco, we analyze, using the solution concept of self-confirming equilibrium, a cultural transmission model where parents have incomplete information about the social structure and the efficacy of their vertical transmission efforts. The last chapter ”Non-Bayesian Social Learning and the Spread of Misinformation in Networks” studies learning in a setting where agents receive each period independent noisy signals about the true state of the world and then communicate in a network where there are stubborn agents who spread misinformation.

Every day, humans are involved in social situations and interplays, with the goal of sharing emotions and thoughts, establishing relationships with or acting on other human beings. These interactions are possible thanks to what is called social intelligence, which is the ability to express and recognize social signals produced during the interactions. These signals aid the information exchange and are expressed through verbal and non-verbal behavioral cues, such as facial expressions, gestures, body pose or prosody. Recently, many works have demonstrated that social signals can be captured and analyzed by automatic systems, giving birth to a relatively new research area called social signal processing, which aims at replicating human social intelligence with machines. In this thesis, we explore the use of behavioral cues and computational methods for modeling and understanding social interactions. Concretely, we focus on several behavioral cues in three specic contexts: rst, we analyze the relationship between gaze and leadership in small group interactions. Second, we expand our analysis to face and head gestures in the context of deception detection in dyadic interactions. Finally, we analyze the whole body for group detection in mingling scenarios.

Human social interaction is as common as complex to understand. It is a part of our routine life ranging from houses to communal places either in direct face-to-face interaction or through digital media. During these interactions, humans exchange their thoughts, intentions, and emotions effectively. They use verbal language along with non-verbal social signals such as variation in voice tune, hand gestures, facial expressions, and body posture. This non-verbal part of communication is still less understood despite the fact of recent huge research progression and computational advancement. Recently, social interactions in groups such as meetings, standing conversations, interviewing, and discussions have become popular areas of research for the social computing domain. In this thesis, we propose and investigate novel computational approaches for the application of emergent leadership detection, leadership style prediction, personality traits classification, and visual voice activity detection in the context of small group interactions. First of all, we investigated emergent leadership detection in small group meeting environments. The leaders are key players in making the decision, facing problems, and as a result, playing an important role in an organization. In organizational behavioral research, the detection of an emergent leader is an important task. From the computing perspective, we propose visual activity-based nonverbal feature extraction from video streams by applying a deep learning approach along with the feature encoding for low dimensional representation. Our method shows improved results even as compared to multi-modal non-verbal features extracted from audio and visual. These novel features also performed well for the application of autocratic or democratic leadership style prediction and the discrimination of high/low extraversion. Afterwards, we explored the problem of voice activity detection (VAD) extensively. VAD is defined as Who is Speaking and When". Usually, VAD is accomplished using audio features only. But, due to some physical or privacy-related constraints, the audio modality is not always accessible which increases the importance of VAD based on visual modality only. Visual VAD is also a very useful for several social interactions analysis-related applications. We performed a detailed analysis to find out an efficient way of representing the raw video streams for this task. A full upper body-based holistic approach is adopted instead of using only lips motion or facial visual features as mostly suggested by the literature. Motivated from psychology literature, gesticulating style while speaking varies from person to person depending upon ethnic background or type of personality. An unsupervised domain adaptation is also adapted and gives a good boost in VAD performance. We introduce the new RealVAD dataset, which is used to benchmark the VAD methods in real-life situations. Lastly, we performed body motion cues based VAD learning in conjunction with a weakly supervised segmentation scheme.