Дисертації з теми "Computational social networks"
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Hamdi, Sana. "Computational models of trust and reputation in online social networks." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLL001/document.
Повний текст джерелаOnline Social Networks (OSNs) have known a dramatic increase and they have been used as means for a rich variety of activities. In fact, within OSNs, usersare able to discover, extend, manage, and leverage their experiences and opinionsonline. However, the open and decentralized nature of the OSNs makes themvulnerable to the appearance of malicious users. Therefore, prospective users facemany problems related to trust. Thus, effective and efficient trust evaluation isvery crucial for users’ decision-making. It provides valuable information to OSNsusers, enabling them to make difference between trustworthy and untrustworthyones. This thesis aims to provide effective and efficient trust and reputationmanagement methods to evaluate trust and reputation of OSNs users, which canbe divided into the following four contributions.The first contribution presents a complex trust-oriented users’ contexts andinterests extraction, where the complex social contextual information is taken intoaccount in modelling, better reflecting the social networks in reality. In addition,we propose an enrichment of the Dbpedia ontology from conceptualizations offolksonomies.We second propose the IRIS (Interactions, Relationship types and Interest Similarity)trust management approach allowing the generation of the trust networkand the computation of direct trust. This model considers social activities of usersincluding their social relationships, preferences and interactions. The intentionhere is to form a solid basis for the reputation and indirect trust models.The third contribution of this thesis is trust inference in OSNs. In fact, it isnecessary and significant to evaluate the trust between two participants whomhave not direct interactions. We propose a trust inference model called TISON(Trust Inference in Social Networks) to evaluate Trust Inference within OSNs.The fourth contribution of this thesis consists on the reputation managementin OSNs. To manage reputation, we proposed two new algorithms. We introducea new exclusive algorithm for clustering users based on reputation, called RepC,based on trust network. In addition, we propose a second algorithm, FCR, whichis a fuzzy extension of RepC.For the proposed approaches, extensive experiments have been conducted onreal or random datasets. The experimental results have demonstrated that ourproposed algorithms generate better results, in terms of the utility of delivered results and efficiency, than do the pioneering approaches of the literature
Grabowicz, Przemyslaw Adam. "Complex networks approach to modeling online social systems. The emergence of computational social science." Doctoral thesis, Universitat de les Illes Balears, 2014. http://hdl.handle.net/10803/131220.
Повний текст джерелаLa presente tesis está dedicada a la descripción, análisis y modelado cuantitativo de sistemas complejos sociales en forma de redes sociales en internet. Mediante el uso de métodos y conceptos provenientes de ciencia de redes, análisis de redes sociales y minería de datos se descubren diferentes patrones estadísticos de los sistemas estudiados. Uno de los objetivos a largo plazo de esta línea de investigación consiste en hacer posible la predicción del comportamiento de sistemas complejos tecnológico-sociales, de un modo similar a la predicción meteorológica, usando inferencia estadística y modelado computacional basado en avances en el conocimiento de los sistemas tecnológico-sociales. A pesar de que el objeto del presente estudio son seres humanos, en lugar de los átomos o moléculas estudiados tradicionalmente en la física estadística, la disponibilidad de grandes bases de datos sobre comportamiento humano hace posible el uso de técnicas y métodos de física estadística. En el presente trabajo se utilizan grandes bases de datos provenientes de redes sociales en internet, se miden patrones estadísticos de comportamiento social, y se desarrollan métodos cuantitativos, modelos y métricas para el estudio de sistemas complejos tecnológico-sociales.
Mui, Lik. "Computational models of trust and reputation : agents, evolutionary games, and social networks." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87343.
Повний текст джерелаIncludes bibliographical references (leaves [131]-139).
Many recent studies of trust and reputation are made in the context of commercial reputation or rating systems for online communities. Most of these systems have been constructed without a formal rating model or much regard for our sociological understanding of these concepts. We first provide a critical overview of the state of research on trust and reputation. We then propose a formal quantitative model for the rating process. Based on this model, we formulate two personalized rating schemes and demonstrate their effectiveness at inferring trust experimentally using a simulated dataset and a real world movie-rating dataset. Our experiments show that the popular global rating scheme widely used in commercial electronic communities is inferior to our personalized rating schemes when sufficient ratings among members are available. The level of sufficiency is then discussed. In comparison with other models of reputation, we quantitatively show that our framework provides significantly better estimations of reputation. "Better" is discussed with respect to a rating process and specific games as defined in this work. Secondly, we propose a mathematical framework for modeling trust and reputation that is rooted in findings from the social sciences. In particular, our framework makes explicit the importance of social information (i.e., indirect channels of inference) in aiding members of a social network choose whom they want to partner with or to avoid. Rating systems that make use of such indirect channels of inference are necessarily personalized in nature, catering to the individual context of the rater. Finally, we have extended our trust and reputation framework toward addressing a fundamental problem for social science and biology: evolution of cooperation.
(cont.) We show that by providing an indirect inference mechanism for the propagation of trust and reputation, cooperation among selfish agents can be explained for a set of game theoretic simulations. For these simulations in particular, our proposal is shown to have provided more cooperative agent communities than existing schemes are able to.
by Lik Mui.
Ph.D.
Yang, Guoli. "Learning in adaptive networks : analytical and computational approaches." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20956.
Повний текст джерелаKuhlman, Christopher J. "High Performance Computational Social Science Modeling of Networked Populations." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51175.
Повний текст джерелаPh. D.
Khan, Pour Hamed. "Computational Approaches for Analyzing Social Support in Online Health Communities." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157594/.
Повний текст джерелаRossi, Maria. "Graph Mining for Influence Maximization in Social Networks." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX083/document.
Повний текст джерелаModern science of graphs has emerged the last few years as a field of interest and has been bringing significant advances to our knowledge about networks. Until recently the existing data mining algorithms were destined for structured/relational data while many datasets exist that require graph representation such as social networks, networks generated by textual data, 3D protein structures and chemical compounds. It has become therefore of crucial importance to be able to extract meaningful information from that kind of data and towards this end graph mining and analysis methods have been proven essential. The goal of this thesis is to study problems in the area of graph mining focusing especially on designing new algorithms and tools related to information spreading and specifically on how to locate influential entities in real-world networks. This task is crucial in many applications such as information diffusion, epidemic control and viral marketing. In the first part of the thesis, we have studied spreading processes in social networks focusing on finding topological characteristics that rank entities in the network based on their influential capabilities. We have specifically focused on the K-truss decomposition which is an extension of the core decomposition of the graph. Extensive experimental analysis showed that the nodes that belong to the maximal K-truss subgraph show a better spreading behavior when compared to baseline criteria. Such spreaders can influence a greater part of the network during the first steps of a spreading process but also the total fraction of the influenced nodes at the end of the epidemic is greater. We have also observed that node members of such dense subgraphs are those achieving the optimal spreading in the network.In the second part of the thesis, we focused on identifying a group of nodes that by acting all together maximize the expected number of influenced nodes at the end of the spreading process, formally called Influence Maximization (IM). The IM problem is actually NP-hard though there exist approximation guarantees for efficient algorithms that can solve the problem while obtaining a solution within the 63% of optimal classes of models. As those guarantees propose a greedy approximation which is computationally expensive especially for large graphs, we proposed the MATI algorithm which succeeds in locating the group of users that maximize the influence while also being scalable. The algorithm takes advantage the possible paths created in each node’s neighborhood to precalculate each node’s potential influence and produces competitive results in quality compared to those of baseline algorithms such as the Greedy, LDAG and SimPath. In the last part of the thesis, we study the privacy point of view of sharing such metrics that are good influential indicators in a social network. We have focused on designing an algorithm that addresses the problem of computing through an efficient, correct, secure, and privacy-preserving algorithm the k-core metric which measures the influence of each node of the network. We have specifically adopted a decentralization approach where the social network is considered as a Peer-to-peer (P2P) system. The algorithm is built based on the constraint that it should not be possible for a node to reconstruct partially or entirely the graph using the information they obtain during its execution. While a distributed algorithm that computes the nodes’ coreness is already proposed, dynamic networks are not taken into account. Our main contribution is an incremental algorithm that efficiently solves the core maintenance problem in P2P while limiting the number of messages exchanged and computations. We provide a security and privacy analysis of the solution regarding network de-anonimization and show how it relates to previously defined attacks models and discuss countermeasures
Shahrezaye, Morteza [Verfasser], Simon [Akademischer Betreuer] Hegelich, Jürgen [Gutachter] Pfeffer, and Simon [Gutachter] Hegelich. "Understanding big social networks: Applied methods for computational social science / Morteza Shahrezaye ; Gutachter: Jürgen Pfeffer, Simon Hegelich ; Betreuer: Simon Hegelich." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1204562296/34.
Повний текст джерелаEk, Adam. "Extracting social networks from fiction : Imaginary and invisible friends: Investigating the social world of imaginary friends." Thesis, Stockholms universitet, Institutionen för lingvistik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-145659.
Повний текст джерелаJoseph, Kenneth. "New Methods for Large-Scale Analyses of Social Identities and Stereotypes." Research Showcase @ CMU, 2016. http://repository.cmu.edu/dissertations/690.
Повний текст джерелаYan, Chang. "A computational game-theoretic study of reputation." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:e6acb250-efb8-410b-86dd-9e3e85b427b6.
Повний текст джерелаShabut, Antesar R. M. "Trust Computational Models for Mobile Ad Hoc Networks. Recommendation Based Trustworthiness Evaluation using Multidimensional Metrics to Secure Routing Protocol in Mobile Ad Hoc Networks." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/7501.
Повний текст джерелаMinistry of Higher Education in Libya and the Libyan Cultural Attaché bureau in London
Shabut, Antesar Ramadan M. "Trust computational models for mobile ad hoc networks : recommendation based trustworthiness evaluation using multidimensional metrics to secure routing protocol in mobile ad hoc networks." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/7501.
Повний текст джерелаAlqithami, Saad. "Network Organization Paradigm." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/dissertations/1293.
Повний текст джерелаWatts, Jameson K. M., and Jameson K. M. Watts. "Language Consistency and Exchange: Market Reactions to Change in the Distribution of Field-level Information." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/556000.
Повний текст джерелаRocha, Luis E. C. "Exploring patterns of empirical networks." Doctoral thesis, Umeå universitet, Institutionen för fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-46588.
Повний текст джерелаVi är ständigt kämpar för att förstå hur naturen fungerar, försöker identifier återkommande evenemang och söker analogier och relationer mellan objekt eller individer. Veta beteendemönster är kraftfull och grundläggande för överlevnad av arter. I denna avhandling, dataset av olika system i samband med transporter är ekonomi, sexuella och sociala kontakter, som kännetecknas av att använda formalismer av tidsserier och nätverk teori. En del av resultatet utgörs av insamling och analys av ursprungliga nätdata, fokuserar resten på simulering av dynamiska processer i dessa nätverk och att studera hur de påverkas av de särskilda strukturer. Huvuddelen av avhandlingen handlar om tidsmässiga nät, i.e. nät vars struktur förändringar i tid. Den nya tidsdimensionen avslöjar strukturella dynamiska egenskaper som hjälper till att förstå den feedback mekanismer som ansvarar för att göra nätverksstruktur att anpassa sig och förstå uppkomsten och hämning av olika företeelser i dynamiska system, epidemier i sexuella och kontaktnät.
Constantemente nos esforçamos para entender como a natureza funciona, tentando identificar eventos recorrentes e procurando por analogias e relações entre objetos ou indivíduos. Conhecer padrões de comportamento é algo poderoso e fundamental para a sobrevivência de qualquer espécie. Nesta tese, dados de sistemas diversos, relacionados a transporte, economia, contatos sexuais e sociais, são caracterizados usando o formalismo de séries temporais e teoria de redes. Uma parte dos resultados consiste na coleta e análise de dados de redes originais, a outra parte concentra-se na simulação de processos dinâmicos nessas redes e no estudo de como esses processos são afetados por determinadas estruturas. A maior parte da tese é sobre redes temporais, ou seja, redes cuja estrutura varia no tempo. A nova dimensão temporal revela propriedades estruturais dinâmicas que contribuem para o entendimento dos mecanismos de resposta responsáveis pela adaptação da rede, e para o entendimento da emergência e inibição de fenômenos diversos em sistemas dinâmicos, como epidemias em redes sexuais e de contato pessoal.
Etling, Bruce. "Network structure, brokerage, and framing : how the internet and social media facilitate high-risk collective action." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:2c08ba3d-2eb0-41ee-ace5-cb1f893c951e.
Повний текст джерелаSrinivasan, Ramprakash. "Computational Models of the Production and Perception of Facial Expressions." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531239299392184.
Повний текст джерелаYou, Bo. "Hub-Network for Distance Computation in Large Social Networks." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1412601464.
Повний текст джерелаShaikh, Sajid S. "COMPUTATION IN SOCIAL NETWORKS." Kent State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1185560088.
Повний текст джерелаShaikh, Sajid S. "Computations in social network." [Kent, Ohio] : Kent State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1185560088.
Повний текст джерелаMignot, Sylvain. "Négocier ou enchérir, l’influence des mécanismes de vente : le cas du marché aux poissons de Boulogne-sur-Mer." Thesis, Paris 2, 2012. http://www.theses.fr/2012PA020101/document.
Повний текст джерелаShould I buy or should I bid ? The influence of market mechanism : the case of Boulogne-Sur-Mer fish market. The Boulogne-sur-Mer fish market is organized in a very specific way. Each day buyers and sellers can choose to use either an auction mechanism, a negotiated market, or evenboth, in order to sell and buy goods.A stunning fact observed is the stable coexistence of those two sub-markets throughout time, with no convergence of agents toward one of them, each one accounting for roughly half of the exchanged quantities.The present thesis aims at discovering the necessary conditions of the emergence andstability of such a coexistence.To do it, we will begin with an empirical study of daily transactions that have occurred on this market for a few years. We begin with a statistical and econometric study to extract the main stylized facts of this market, then we study the social networks influencing the outcomes. Once those facts determined, we build agent-based computational models able to reproduce the individual behaviours of agents, and through these, the emergence of the market’sbehaviour itself
Obradović, Darko [Verfasser]. "Computational Social Network Analysis of Authority in the Blogosphere / Darko Obradović." München : Verlag Dr. Hut, 2012. http://d-nb.info/1028786891/34.
Повний текст джерелаLospinoso, Joshua Alfred. "Statistical models for social network dynamics." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:d5ed9b9c-020c-4379-a5f2-cf96439ca37c.
Повний текст джерелаWilczynski, Anaëlle. "Interaction entre agents modélisée par un réseau social dans des problématiques de choix social computationnel Strategic Voting in a Social Context: Considerate Equilibria Object Allocation via Swaps along a Social Network Local Envy-Freeness in House Allocation Problems Constrained Swap Dynamics over a Social Network in Distributed Resource Reallocation Poll-Confident Voters in Iterative Voting." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLED073.
Повний текст джерелаSocial choice is the study of collective decision making, where a set of agents must make a decision over a set of alternatives, according to their preferences. The question relies on how aggregating the preferences of the agents in order to end up with a decision that is commonly acceptable for the group. Typically, agents can interact by collaborating, or exchanging some information. It is usually assumed in computational social choice that every agent is able to interact with any other agent. However, this assumption looks unrealistic in many concrete situations. We propose to relax this assumption by considering that the possibility of interaction is given by a social network, represented by a graph over the agents.In this context, we study two particular problems of computational social choice: strategic voting and resource allocation of indivisible goods. The focus is on two types of interaction: collaboration and information gathering. We explore how the social network,modelingapossibilityofcollaboration or a visibility relation among the agents, can impact the resolution and the solution of voting and resource allocation problems. These questions are addressed via computational social choice by using tools from algorithmic game theory and computational complexity
Ballester, Pla Coralio. "On Peer Networks and Group Formation." Doctoral thesis, Universitat Autònoma de Barcelona, 2005. http://hdl.handle.net/10803/4064.
Повний текст джерелаPara obtener nuestros resultados, utilizamos el concepto de NP-completitud, que es un modelo bien establecido de complejidad temporal en Ciencias de la Computación. En concreto, nos concentramos en estabilidad grupal y estabilidad individual en juegos hedónicos. Los juegos hedónicos son una clase simple de juegos cooperativos en los que la utilidad de cada individuo viene totalmente determinada por el grupo laboral al que pertenece. Nuestros resultados referentes a la complejidad, expresados en términos de NP-completitud, cubren un amplio espectro de dominios de las preferencias individuales, incluyendo preferencias estrictas, indiferencias en las preferencias o preferencias libres sobre el tamaño de los grupos. Dichos resultados también se cumplen si nos restringimos al caso en el que el tamaño máximo de los grupos es pequeño (dos o tres jugadores)
En el artículo "Who is Who in Networks. Wanted: The Key Player" (junto con Antoni Calvó Armengol e Yves Zenou), analizamos un modelo de efectos de grupo en el que los agentes interactúan en un juego de influencias bilaterales. Los juegos no cooperativos con población finita y utilidades linales-cuadráticas, en los cuales cada jugador decide cuánto esfuerzo ejercer, pueden ser interpretados como juegos en red con complementariedades en los pagos, junto con un componente de susitucion global y uniforme, y un efecto de concavidad propia.
Para dichos juegos, la acción de cada jugador en un equilibrio de Nash es proporcional a su centralidad de Bonacich en la red de complementariedades, estableciendo así un puente con la literatura de redes sociales. Dicho vínculo entre Bonacich y Nash implica que el equilibrio agregado aumenta con el tamaño y la densidad de la red.
También analizamos una política que consiste en seleccionar al jugador clave, ésto es, el jugador que, una vez eliminado del juego, induce un cambio óptimo en la actividad agregada. Proveemos una caracterización geométrica del jugador clave, identificada con una medida de inter-centralidad, la cual toma en cuenta tanto la centralidad de cada jugador como su contribución a la centralidad de los otros.
En el artículo "Optimal Targets in Peer Networks" (junto con Antoni Calvó Armengol e Yves Zenou), nos centramos en las consecuencias y limitaciones prácticas que se derivan del modelo de decisiones sobre delincuencia. Las principales metas que aborda el trabajo son las siguientes. Primero, la elección se extiende el concepto de delincuente clave en una red al de grupo clave. En dicha situación se trata de seleccionar de modo óptimo al conjunto de delincuentes a eliminar/neutralizar, dadas las restricciones presupuestarias para aplicar medidas. Dicho problema presenta una inherente complejidad computacional que solo puede salvarse mediante el uso de procedimientos aproximados, "voraces" o probabilísticos. Por otro lado, tratamos el problema del delincuente clave en el contexto de redes dinámicas, en las que, inicialmente, los individuos deciden acerca de su futuro como delincuentes o como ciudadanos que obtienen un salario fijo en el mercado. En dicha situación, la elección del delincuente clave es más compleja, ya que el objetivo de disminuir la delincuencia debe tener en cuenta los efectos en cadena que pueda traer consigo la desaparición de uno o varios delincuentes. Por último, estudiamos la complejidad computacional del problema de elección óptima y explotamos la propiedad de submodularidad de la intercentralidad de grupo, lo cual nos permite acotar el error relativo de la aproximación basada en un algoritmo voraz.
The aim of this thesis work is to contribute to the analysis of the interaction of agents in social networks and groups.
In the chapter "NP-completeness in Hedonic Games", we identify some significant limitations in standard models of cooperation in games: It is often impossible to achieve a stable organization of a society in a reasonable amount of time. The main implications of these results are the following. First, from a positive point of view, societies are bound to evolve permanently, rather than reach a steady state configuration rapidly. Second, from a normative perspective, a planner should take into account practical time limitations in order to implement a stable social order.
In order to obtain our results, we use the notion of NP-completeness, a well-established model of time complexity in Computer Science. In particular, we concentrate on group stability and individual stability in hedonic games. Hedonic games are a simple class of cooperative games in which each individual's utility is entirely determined by her group. Our complexity results, phrased in terms of NP-completeness, cover a wide spectrum of preference domains, including strict preferences, indifference in preferences or undemanding preferences over sizes of groups. They also hold if we restrict the maximum size of groups to be very small (two or three players).
The last two chapters deal with the interaction of agents in the social setting. It focuses on games played by agents who interact among them. The actions of each player generate consequences that spread to all other players throughout a complex pattern of bilateral influences.
In "Who is Who in Networks. Wanted: The Key Player" (joint with Antoni Calvó-Armengol and Yves Zenou), we analyze a model peer effects where agents interact in a game of bilateral influences. Finite population non-cooperative games with linear-quadratic utilities, where each player decides how much action she exerts, can be interpreted as a network game with local payoff complementarities, together with a globally uniform payoff substitutability component and an own-concavity effect.
For these games, the Nash equilibrium action of each player is proportional to her Bonacich centrality in the network of local complementarities, thus establishing a bridge with the sociology literature on social networks. This Bonacich-Nash linkage implies that aggregate equilibrium increases with network size and density. We then analyze a policy that consists in targeting the key player, that is, the player who, once removed, leads to the optimal change in aggregate activity. We provide a geometric characterization of the key player identified with an inter-centrality measure, which takes into account both a player's centrality and her contribution to the centrality of the others.
Finally, in the last chapter, "Optimal Targets in Peer Networks" (joint with Antoni Calvó-Armengol and Yves Zenou), we analyze the previous model in depth and study the properties and the applicability of network design policies.
In particular, the key group is the optimal choice for a planner who wishes to maximally reduce aggregate activity. We show that this problem is computationally hard and that a simple greedy algorithm used for maximizing submodular set functions can be used to find an approximation. We also endogeneize the participation in the game and describe some of the properties of the key group. The use of greedy heuristics can be extended to other related problems, like the removal or addition of new links in the network.
Santos, Francisco C. "Topological evolution: from biological to social networks." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210702.
Повний текст джерелаABOUEIMEHRIZI, MOHAMMAD. "Election Control via Social Influence." Doctoral thesis, Gran Sasso Science Institute, 2021. http://hdl.handle.net/20.500.12571/21656.
Повний текст джерелаNagurney, Anna, and Dae-Shik Kim. "Parallel Computation of Large-Scale Nonlinear Network Problems in the Social and Economic Sciences." Massachusetts Institute of Technology, Operations Research Center, 1990. http://hdl.handle.net/1721.1/5400.
Повний текст джерелаRiquelme, Csori Fabián. "Structural and computational aspects of simple and influence games." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/283144.
Повний текст джерелаLos juegos simples son una clase fundamental de juegos cooperativos, que tiene una enorme relevancia en diversas áreas de ciencias de la computación, ciencias sociales y matemáticas discretas aplicadas. En los últimos años, los distintos aspectos algorítmicos y de complejidad computacional de los juegos simples ha ido ganando notoriedad. En esta tesis revisamos los distintos problemas computacionales relacionados con propiedades, parámetros y conceptos de solución de juegos simples. Primero consideramos distintas formas de representación de juegos simples, juegos regulares y juegos de mayoría ponderada, y estudiamos la complejidad computacional requerida para transformar un juego desde una representación a otra. También analizamos la complejidad de varios problemas abiertos bajo diferentes formas de representación. En este sentido, demostramos que el problema de decidir si un juego simple en forma ganadora minimal es decisivo (un problema asociado al problema de dualidad de hipergrafos y funciones booleanas monótonas) puede resolverse en tiempo cuasi-polinomial, y que este problema puede reducirse polinomialmente al mismo problema pero restringido a juegos regulares en forma ganadora shift-minimal. También demostramos que el problema de decidir si un juego regular en forma ganadora shift-minimal es fuerte (strong) es coNP-completo. Adicionalmente, para juegos simples en forma ganadora minimal demostramos que el parámetro de anchura (width) puede computarse en tiempo polinomial. Independientemente de la forma de representación, también estudiamos problemas de enumeración y conteo para varias subfamilias de juegos simples. Luego introducimos los juegos de influencia, un nuevo enfoque para estudiar juegos simples basado en un modelo de dispersión de influencia en redes sociales, donde la influencia se dispersa de acuerdo con el modelo de umbral lineal (linear threshold model). Demostramos que los juegos de influencia abarcan la totalidad de la clase de los juegos simples. Para estos juegos también estudiamos la complejidad de los problemas relacionados con parámetros, propiedades y conceptos de solución considerados para los juegos simples. Además consideramos casos extremos con respecto a la demanda de influencia, y probamos que para ciertas subfamilias, varios de estos problemas se vuelven polinomiales. Finalmente estudiamos algunas aplicaciones inspiradas en los juegos de influencia. El primer conjunto de estos resultados tiene que ver con la definición de modelos de decisión colectiva. Para sistemas de mediación, varios de los problemas de propiedades mencionados anteriormente son polinomialmente resolubles. Para los sistemas de influencia, demostramos que computar la satisfacción (una medida equivalente al índice de Rae y similar al valor de Banzhaf) es difícil a menos que consideremos algunas restricciones en el modelo. Para los sistemas OLFM, una generalización de los sistemas OLF (van den Brink et al. 2011, 2012) proporcionamos una axiomatización para la medida de satisfacción. El segundo conjunto de resultados se refiere al análisis de redes sociales, y en particular con la definición de nuevas medidas de centralidad de redes sociales, que comparamos en redes reales con otras medidas de centralidad clásicas
Takhtamysheva, Aneta Verfasser], Rainer [Akademischer Betreuer] Malaka, and Andreas [Akademischer Betreuer] [Breiter. "Human Computation and Human Subject Tasks in Social Network Playful Applications / Aneta Takhtamysheva. Betreuer: Rainer Malaka. Gutachter: Rainer Malaka ; Andreas Breiter." Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1094955884/34.
Повний текст джерелаGraversen, Therese. "Statistical and computational methodology for the analysis of forensic DNA mixtures with artefacts." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:4c3bfc88-25e7-4c5b-968f-10a35f5b82b0.
Повний текст джерелаSariyuce, Ahmet Erdem. "Fast Algorithms for Large-Scale Network Analytics." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429825578.
Повний текст джерелаLampert, Marco Andrei. "Análise Da Relevância De Mensagens No Twitter Através De Um Sistema Multi-Agente." Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4547.
Повний текст джерелаMade available in DSpace on 2015-07-17T23:13:03Z (GMT). No. of bitstreams: 1 35c.pdf: 1699465 bytes, checksum: d02851ad31e9068e1eae089ab0df0940 (MD5) Previous issue date: 2012
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O surgimento de novas tecnologias e as inovações em mídias sociais têm alterado a forma como as pessoas se comportam. Destacadamente as Redes Sociais estão cada vez mais inseridas na vida das pessoas. Nunca houve tanto desenvolvimento, penetração, diversificação, dispersão da informação, comunicação em tempo real, compressão do espaço e tempo, concomitante com a pluralidade de perspectivas, definições, análises e de cenários prospectivos sobre os possí- veis desdobramentos dos fatos do presente. Convergência está em todo lugar e nunca foi tão fácil atingir um público tão grande. Diante deste cenário exploramos as pesquisas existentes e propomos uma abordagem para analisar a relevância de mensagens do Twitter, monitorando a sua evolução na rede e estabelecendo a influência exercida em um espaço demográfico. Desenvolvemos uma aplicação capaz de fazer esta monitoração, com intuito de verificar e validar o modelo proposto.
The appearance of new technologies and innovations in social media has changed the way how people behave themself. Remarkably Social Networks are more and more incorporated in people’s lives. There has never been so much development, penetration, diversification, dispersion, real-time communication, compression of space and time, concomitant with a plurality of perspectives, definitions, analysis and prospective scenarios on the possible unfolding of the facts of the present. Convergence is everywhere and has never been so easy to achieve such a large audience. In this scenario we explore the existing research and we propose an approach to analyze the relevance of Twitter messages, monitoring its evolution in the network and establishing the influence in a demographic space. We develop an application able to do this monitoring, with the intent to verify and validate the proposed model.
CAMPEDELLI, GIAN MARIA. "ON META-NETWORKS, DEEP LEARNING, TIME AND JIHADISM." Doctoral thesis, Università Cattolica del Sacro Cuore, 2020. http://hdl.handle.net/10280/70552.
Повний текст джерелаJihadist terrorism represents a global threat for societies and a challenge for scientists interested in understanding its complexity. This complexity continuously calls for developments in terrorism research. Enhancing the empirical knowledge on the phenomenon can potentially contribute to developing concrete real-world applications and, ultimately, to the prevention of societal damages. In light of these aspects, this work presents a novel methodological framework that integrates network science, mathematical modeling, and deep learning to shed light on jihadism, both at the explanatory and predictive levels. Specifically, this dissertation will compare and analyze the world's most active jihadist terrorist organizations (i.e. The Islamic State, the Taliban, Al Qaeda, Boko Haram, and Al Shabaab) to investigate their behavioral patterns and forecast their future actions. Building upon a theoretical framework that relies on the spatial concentration of terrorist violence and the strategic perspective of terrorist behavior, this dissertation will pursue three linked tasks, employing as many hybrid techniques. Firstly, explore the operational complexity of jihadist organizations using stochastic transition matrices and present Normalized Transition Similarity, a novel coefficient of pairwise similarity in terms of strategic behavior. Secondly, investigate the presence of time-dependent dynamics in attack sequences using Hawkes point processes. Thirdly, integrate complex meta-networks and deep learning to rank and forecast most probable future targets attacked by the jihadist groups. Concerning the results, stochastic transition matrices show that terrorist groups possess a complex repertoire of combinations in the use of weapons and targets. Furthermore, Hawkes models indicate the diffused presence of self-excitability in attack sequences. Finally, forecasting models that exploit the flexibility of graph-derived time series and Long Short-Term Memory networks provide promising results in terms of correct predictions of most likely terrorist targets. Overall, this research seeks to reveal how hidden abstract connections between events can be exploited to unveil jihadist mechanics and how memory-like processes (i.e. multiple non-random parallel and interconnected recurrent behaviors) might illuminate the way in which these groups act.
Theodoni, Panagiota. "Fluctuations in perceptual decisions : cortical microcircuit dynamics mediating alternations in conscious visual perception." Doctoral thesis, Universitat Pompeu Fabra, 2014. http://hdl.handle.net/10803/145642.
Повний текст джерелаLes fluctuacions en les decisions perceptives sorgeixen quan el nostre cervell s'enfronta a estímuls sensorials ambigus. Per exemple, la nostra percepció alterna entre dues imatges contradictòries quan es presenten de forma dicòptica als nostres ulls, cosa que permet una dissociació de l'estimulació sensorial de la percepció visual conscient, i per tant proporciona una porta d'entrada a la consciència. Com funciona el cervell quan es tracta d'aquest tipus d'estímuls sensorials ambigus? Hem tractat aquesta qüestió de forma teòrica mitjançant l'ús d'una xarxa d'atractors biofísicament realista, reduint-la de forma consistent a un model de quatre variables basat en la freqüència, i extraient expressions analítiques pels estadístics de segon ordre. Hem emprat dades neurofisiològiques de comportament d'humans i macacos recollides quan els subjectes s'enfrontaven a aquest tipus d'ambigüitats. Els nostres resultats mostren la importància de l'adaptació neuronal en la presa de decisions perceptives i mostren la seva contribució a l'equilibri velocitat-precisió. D'altra banda, els nostres resultats confirmen que tant el soroll com l'adaptació neural operen en equilibri durant els estats fluctuants de consciència visual i suggereixen que, si bé l'adaptació en la inhibició no és rellevant per a les alternances de percepció, contribueix a la dinàmica del cervell en repòs. Finalment, expliquem la decorrelació del soroll neuronal observada durant la consciència visual i proporcionem noves idees en relació a l’antiga qüestió de en quin lloc del cervell es resol la rivalitat visual.
Li, Vigni Guido Fabrizio. "Les systèmes complexes et la digitalisation des sciences. Histoire et sociologie des instituts de la complexité aux États-Unis et en France." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEH134/document.
Повний текст джерелаHow to think the relationship between contemporary scientific cultures and the rising usage of computer in the production of knowledge ? This thesis offers to give an answer to such a question, by analyzing historically and sociologically a scientific domain founded by the Santa Fe Institute (SFI) in the 1980s in the United States : the « complex systems sciences » (CSS). Become well-known thanks to popular books and articles, CSS have spread in Europe and in other countries of the world in the course of the 1990s and the 2000s. This work proposes a history of the foundation of this domain, by focussing on the SFI and on the French Complex Systems National Network. With a sociological take rooted into Science & Technology Studies and into pragmatism, it then asks some questions about the socio-epistemic status of such a domain, about the modalities of production of evidence as they are employed in the context of digital simulation and, finally, about the epistemic engagements hold by complexity specialists. Empirical material – composed by circa 200 interviews, several thousands archival pages and a small number of laboratory visits – allows us not only to improve knowledge about this field – whose language is very common today, but little studied by historians and sociologists ; it also brings us to question three current opinions in the human and social sciences literature regarding digital sciences. That is : 1) that the computer produces more and more interdisciplinary knowledge, 2) that it gives birth to a new type of knowledge which needs an entirely new epistemology to be well understood and 3) that it inevitably brings about neoliberal visions of the world. Now, this thesis deconstructs these three forms of technological determinism concerning the effects of computer on scientific practices, by showing firstly that, in digital sciences, the interdisciplinary collaborations are not made without any effort and in a symetrical and pacific way ; secondly, that CSS’ researchers mobilize a kind of evidence production techniques which are well known in other disciplines ; and, thirdly, that scientists’ epistemic engagements can take (neo)liberal forms, but also other forms that depart from neoliberalism or that stand against it
Navarro, Emmanuel. "Métrologie des graphes de terrain, application à la construction de ressources lexicales et à la recherche d'information." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2013. http://tel.archives-ouvertes.fr/tel-01020232.
Повний текст джерелаTsai, Yu-Shiuan, and 蔡宇軒. "Network-based Computational Epidemiology: A Multilayer Framework Integrating Social Networks with Epidemic Dynamics." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/60758616028093627810.
Повний текст джерела國立交通大學
資訊科學與工程研究所
99
Network-based computational epidemiologists use computers and either theoretical or actual network topologies to study the transmission dynamics of human diseases and social trends. In this dissertation I discuss the importance, current status, advantages, and modeling procedures of network-based computational epidemiology, specifically presenting three original studies in detail. The first study is an investigation of how resources and transmission costs influence diffusion dynamics and tipping points in scale-free networks. An epidemic model based on an analytic equation is proposed to explain the existence of epidemic critical thresholds in scale-free networks. Study results suggest the possibility of controlling the spread of epidemics in scale-free networks by manipulating resources and costs associated with an infection event. In the second study, a proposal for a multilayer epidemiological framework that integrates realistic social networks, called the Multilayer Epidemic Dynamics Simulator (MEDSim), is described from individual and national perspectives. Model flexibility and generalizability are tested using outbreak locations and intervention scenarios for the 2009 A/H1N1 influenza epidemic in Taiwan. The results coincide with the dynamic processes of epidemics under different intervention scenarios, thus clarifying the effects of complex contact structures on disease transmission dynamics. In the third study, the potential benefits of epidemic simulations and instructions for building network-based epidemic models by novices learning network-based computational epidemiology approaches is investigated. The goal is to help individuals with less advanced computing skills build epidemiological models, determine appropriate simulation parameters, and construct operational procedures. It is my hope that the studies presented in this dissertation can assist in efforts by public health organizations to correctly implement intervention strategies by using simulations to analyze multilayer interactions.
"Algorithms and computational complexity of social influence and diffusion problems in social networks." 2015. http://repository.lib.cuhk.edu.hk/en/item/cuhk-1291255.
Повний текст джерелаTo better capture the utilization of OPV’s contact immunity, we model the community as a social network, and formulate the task of maximizing the contact immunity effect as an optimization problem on graphs, which is to find a sequence of vertices to be “vaccinated” to maximize the total number of vertices “infected” by the attenuated virus. Furthermore, as immune defiicient patients may suffer from the live attenuated virus in the vaccine, we develop models in consideration of this restriction, and study related problems.
We present polynomial-time algorithms for these problems on trees, and show the intractability of problems on general graphs.
社交網絡的擴散模型被廣泛運用于對流行病學的研究,在本文中,我們使用擴散模型對減毒活疫苗產生的接觸性免疫進行研究。口服脊髓灰質炎疫苗(OPV)是一種典型的減毒活疫苗,它可以在人群中產生接觸性免疫,使得更多未接種疫苗的人獲得免疫力。
爲了更好的刻畫OPV 產生的接觸性免疫,我們將社區模型化為社交網絡,從而將接觸性免疫效應最大化的任務轉化爲圖優化問題,即通過發現頂點的一個「接種」序列來最大化被減活病毒「感染」的頂點數量。此外,因爲減毒疫苗中的活病毒會使患有免疫缺陷的病人患病,我們考慮在此因素限制下的模型,并研究相關的問題。
我們給出這些問題在樹上的多項式時間算法,并證明其在一般圖上的複雜性。
Ma, Chenglong.
Thesis M.Phil. Chinese University of Hong Kong 2015.
Includes bibliographical references (leaves 40-47).
Abstracts also in Chinese.
Title from PDF title page (viewed on 12, September, 2016).
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Gupta, Mona. "Anaytics on behavior of users on large datasets." Thesis, 2017. http://localhost:8080/iit/handle/2074/7294.
Повний текст джерелаWaniek, Marcin. "Hiding in Social Networks." Doctoral thesis, 2017. https://depotuw.ceon.pl/handle/item/2174.
Повний текст джерелаInternet oraz media społecznościowe spowodowały ogromny wzrost zainteresowania metodami analizy sieci społecznych. Coraz bardziej zaawansowane narzędzia służą do analizy naszych powiązań z innymi ludźmi.Rodzi to poważne obawy związane z prywatnością. Mając to na uwadze, rozważamy następujące pytanie: Czy członek lub grupa członków sieci społecznej może aktywnie zarządzać swoimi połączeniami tak, aby uniknąć wykrycia przez narzędzia analizy sieci społecznych? Odpowiedź na to pytanie pozwoliłaby użytkownikom Internetu lepiej chronić swoją prywatność, grupom aktywistów lepiej ukrywać swoją działalność, a agencjom bezpieczeństwa lepiej rozumieć w jaki sposób organizacje terrorystyczne i kryminalne mogą unikać wykrycia.W tej pracy rozważamy ukrywanie się przed trzema różnymi narzędziami analizy sieci społecznych. Po pierwsze, badamy jak pojedynczy węzeł lub ich grupa może uniknąć wykrycia przez miary centralności (ang. centrality measures), wciąż pozostając zdolnym do brania udziału w działalności sieci. Po drugie, analizujemy jak grupa węzłów może uniknąć zidentyfikowania przez algorytmy wykrywania społeczności (ang. community detection algorithms). Po trzecie wreszcie, badamy jak można ukryć istnienie określonej krawędzi w sieci przed algorytmami przewidywania połączeń (ang. link prediction algorithms).Analizujemy złożoność obliczeniową rozważanych zagadnień oraz udowadniamy, że większość z nich to problemy NP-trudne. Tym niemniej prezentujemy również wielomianowe rozwiązania heurystyczne, które okazują się efektywne w praktyce. Nasze algorytmy testujemy na szeregu różnych sieci, tak prawdziwych, jak i wygenerowanych losowo.
Zhang, Shaodian. "Computational Approaches to Characterizing Online Health Communities." Thesis, 2016. https://doi.org/10.7916/D82Z15JX.
Повний текст джерелаGruzd, Anatoliy A., and Caroline Haythornthwaite. "Automated Discovery and Analysis of Social Networks from Threaded Discussions." 2008. http://hdl.handle.net/10150/105081.
Повний текст джерелаGruzd, Anatoliy. "Name Networks: A Content-Based Method for Automated Discovery of Social Networks to Study Collaborative Learning." 2009. http://hdl.handle.net/10150/105553.
Повний текст джерела"Three Facets of Online Political Networks: Communities, Antagonisms, and Polarization." Doctoral diss., 2019. http://hdl.handle.net/2286/R.I.55512.
Повний текст джерелаDissertation/Thesis
Doctoral Dissertation Computer Science 2019
Branzei, Simina. "Two Coalitional Models for Network Formation and Matching Games." Thesis, 2011. http://hdl.handle.net/10012/6112.
Повний текст джерелаShabut, Antesar R. M., Keshav P. Dahal, and Irfan U. Awan. "Friendship based trust model to secure routing protocols in mobile Ad Hoc networks." 2014. http://hdl.handle.net/10454/10787.
Повний текст джерелаTrust management in mobile ad hoc networks (MANETs) has become a significant issue in securing routing protocols to choose reliable and trusted paths. Trust is used to cope with defection problems of nodes and stimulate them to cooperate. However, trust is a highly complex concept because of the subjective nature of trustworthiness, and has several social properties, due to its social origins. In this paper, a friendship-based trust model is proposed for MANETs to secure routing protocol from source to destination, in which multiple social degrees of friendships are introduced to represent the degree of nodes' trustworthiness. The model considers the behaviour of nodes as a human pattern to reflect the complexity of trust subjectivity and different views. More importantly, the model considers the dynamic differentiation of friendship degree over time, and utilises both direct and indirect friendship-based trust information. The model overcomes the limitation of neglecting the social behaviours of nodes when evaluating trustworthiness. The empirical analysis shows the greater robustness and accuracy of the trust model in a dynamic MANET environment.
Spiliotopoulos, Anastasios. "Studying social network sites with the combination of traditional social science and computational approaches." Doctoral thesis, 2020. http://hdl.handle.net/10400.13/3130.
Повний текст джерелаAs Redes Sociais (SNSs - Social Network Sites) estão a mudar de form fundamental a maneira como os seres humanos estabelecem ligações entre si, como comunicam e como relacionam-se uns com os outros, tendo atraído uma considerável quantidade de atenção investigativa. Em geral, duas abordagens de investigação distintas foram seguidas na procura de resultados nesta área de investigação. Em primeiro lugar, os já estabelecidos métodos tradicionais das ciências sociais, tais como inquéritos e entrevistas foram amplamente utilizados na investigação baseada em SNSs. Contudo, o surgimento mais recente das Interfaces de Programação de Aplicações (APIs - Application Programming Interfaces) tem permitido abordagens centradas em dados que têm culminado em estudos de "dados extensos", livres de teoria. Ambas estas abordagens têm vantagens, desvantagens e limitações que precisam de ser consideradas nos estudos de SNS. O objectivo desta dissertação é demonstrar como uma combinação adequada destas duas abordagens pode levar a uma melhor compreensão do comportamento do utilizador em SNSs e pode melhorar a concepção de tais sistemas. Para esse efeito, apresento dois estudos, em duas partes, que funcionam como quatro peças de prova em apoio a este objectivo. Estes estudos investigam, em particular, se uma combinação de dados recolhidos através de inquéritos e API pode fornecer valor adicional e conhecimentos ao a) prever as motivações do Facebook, b) compreender a selecção dos meios de comunicação social, c) compreender os padrões de comunicação no Facebook, e d) prever e modelar a força dos laços, em comparação com o que pode ser ganho seguindo uma ciência social tradicional ou uma abordagem computacional isolada. Abordo em seguida como os resultados destes estudos contribuem para uma compreensão do comportamento online tanto a nível do utilizador individual, por exemplo, como as pessoas percorrem o ecossistema SNS, e ao nível das relações diádicas, por exemplo, como a força dos laços e a confiança interpessoal afectam os padrões de comunicação diádica. Além disso, descrevo as implicações específicas para os designers e investigadores do SNS que decorrem deste trabalho. Por exemplo, o trabalho apresentado tem implicações teóricas para o quadro de Usos e Gratificações (U&G - Uses and Gratifications framework) e para a aplicação da Teoria da Escolha Racional (RCT - Rational Choice Theory) no contexto das interacções SNS, e implicações de design, como o reforço da privacidade e conveniência dos utilizadores de SNS, com o apoio à reciprocidade das interacções. Explico também como os resultados dos estudos realizados demonstram o valor acrescentado de combinar as ciências sociais tradicionais e os métodos computacionais para o estudo de SNS, e, por fim, apresento reflexões sobre os pontos fortes e limitações da abordagem global de investigação que podem ser úteis a esforços de investigação semelhantes.
LIAO, YU-FENG, and 廖裕楓. "Community-Oriented Credit Computation for Distributed Social Network Platform." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/89279827683678964370.
Повний текст джерела國立中央大學
資訊工程學系
105
This thesis wants to design a community-oriented credit s on social network platform. The community-oriented credit is based on the personalized credit on WeOS platform. The personalized credit is based on actions and reputations on the internet. Reputations on the internet are global. All people see the same score. It does not have personalized difference. Personalized credit has personalized difference. But has heavy computation. Community-oriented credit is between both. This thesis wants to apply a community-oriented credit on WeOS platform.The WeOS platform is a web platform based on P2P (Peer-to-Peer) structure.On the platform, users can use many service such as forum provided by themself or other people. This thesis use the simulating data to compute community-oriented credit with distributed structure. The dataset is divided by different number of user to compute time. Finally, the thesis designs a community-oriented credit that can work on social network platform.