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1
Schuhart, Russell G. "Hacking social networks examining the viability of using computer network attack against social networks". Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FSchuhart.pdf.
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Thesis (M.S. in Information Systems and Operations)--Naval Postgraduate School, March 2007.Thesis Advisor(s): David Tucker. "March 2007." Includes bibliographical references (p. 55-56). Also available in print.
2
Tarasenko, O. M. "Social networks". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/40502.
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Nowadays millions of people use social networks. They got
used to surfing on the Internet because it is quick and very easy to
discover anything you wish. You don‘t need to think of suggestions
and ideas. At least what you need is to be able to type correctly.
3
Farry, Michael P. (Michael Patrick). "Sensor networks for social networks". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36764.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 51-55).
This thesis outlines the development of software that makes use of Bayesian belief networks and signal processing techniques to make meaningful inferences about real-world phenomena using data obtained from sensor networks. The effectiveness of the software is validated by applying it to the problem of detecting face-to-face social interactions between groups of people, given data readings from sensors that record light, temperature, acceleration, sound, and proximity. This application represents a novel method for social network construction which is potentially more accurate and less intrusive than traditional methods, but also more meaningful than newer methods that analyze digitally mediated communication.
by Michael P. Farry.
M.Eng.
4
Araújo, Ricardo Matsumura de. "Memetic networks : problem-solving with social network models". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/25515.
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Sistemas sociais têm se tornado cada vez mais relevantes para a Ciência da Computação em geral e para a Inteligência Artificial em particular. Tal interesse iniciou-se pela necessidade de analisar-se sistemas baseados em agentes onde a interação social destes agentes pode ter um impacto no resultado esperado. Uma tendência mais recente vem da área de Processamento Social de Informações, Computação Social e outros métodos crowdsourced, que são caracterizados por sistemas de computação compostos de pessoas reais, com um forte componente social na interação entre estas. O conjunto de todas interações sociais e os atores envolvidos compõem uma rede social, que pode ter uma forte influência em o quão eficaz ou eficiente o sistema pode ser. Nesta tese, exploramos o papel de estruturas de redes em sistemas sociais que visam a solução de problemas. Enquadramos a solução de problemas como uma busca por soluções válidas em um espaço de estados e propomos um modelo - a Rede Memética - que é capaz de realizar busca utilizando troca de informações (memes) entre atores interagindo em uma rede social. Tal modelo é aplicado a uma variedade de cenários e mostramos como a presença da rede social pode melhorar a capacidade do sistema em encontrar soluções. Adicionalmente, relacionamos propriedades específicas de diversas redes bem conhecidas ao comportamento observado para os algoritmos propostos, resultando em um conjunto de regras gerais que podem melhorar o desempenho de tais sistemas sociais. Por fim, mostramos que os algoritmos propostos são competitivos com técnicas tradicionais de busca heurística em diversos cenários.Social systems are increasingly relevant to computer science in general and artificial intelligence in particular. Such interest was first sparkled by agent-based systems where the social interaction of such agents can be relevant to the outcome produced. A more recent trend comes from the general area of Social Information Processing, Social Computing and other crowdsourced systems, which are characterized by computing systems composed of people and strong social interactions between them. The set of all social interactions and actors compose a social network, which may have strong influence on how effective the system can be. In this thesis, we explore the role of network structure in social systems aiming at solving problems, focusing on numerical and combinatorial optimization. We frame problem solving as a search for valid solutions in a state space and propose a model - the Memetic Network - that is able to perform search by using the exchange of information, named memes, between actors interacting in a social network. Such model is applied to a variety of scenarios and we show that the presence of a social network greatly improves the system capacity to find good solutions. In addition, we relate specific properties of many well-known networks to the behavior displayed by the proposed algorithms, resulting in a set of general rules that may improve the performance of such social systems. Finally, we show that the proposed algorithms can be competitive with traditional heuristic search algorithms in a number of scenarios.
5
Trevillion, Steven. "Social work and social networks". Thesis, Brunel University, 1998. http://bura.brunel.ac.uk/handle/2438/5522.
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An exploration of the relationship between patterns of social interaction and social work practice which incorporates thirteen publications. The thread running throughout is the way in which new forms of social care practice are made possible by cross-boundary linkages. A 'Critical Review' sets the context and analyses the works. This is followed by the first published work which applies anthropological models to the study of social marginalisation. The second publication introduces the social network concept and investigates patterns of reciprocity and dependency in social care. The next section of the thesis consists of a 'commentary' on the Griffiths and Wagner Reports. This is followed by a closely related work arguing that there is a fundamental opposition between market and network models of social and community care. The thesis then looks at the ways the culture concept can be used to illuminate the cross-boundary practices associated with community care. The concept of culture and its relationship to cross-boundary working is developed more fully in the next section where it is argued that collaboration culture is paradoxical because it incorporates both respect for difference and a commitment to collective action and that resolving this paradox through collaborative work is a complex and skilled activity. The next section introduces a comparative dimension and suggests that studies of collaboration could be based on looking at the ways in which modern welfare systems try to solve the problem of potential fragmentation and lack of coherence. The work which follows on from this makes use of discourse analysis and network analysis to compare and contrast the rhetoric of partnership and collaboration with the way in which individuals think about their day-to-day cross-boundary work. This raises questions about the changing nature of working relationships in the field of social care and is followed by an investigation into the nature and effects of globalisation on social work in Europe. 'The Co-operation Concept in a Team of Swedish Social Workers' is an attempt to develop a cross-national framework for the analysis of community care focused on the cross-boundary networks of a team of hospital based social workers in Stockholm. The thesis then returns to somewhat broader concerns by means of a work which investigates the contribution of theories of social interaction to theories of social work. These concerns permeate the penultimate section on networking but in a more applied and specific way. The book which constitutes this section of the thesis argues that there is a distinctive theory of networking and that it can be applied to the whole range of social welfare and social care specialisms. The final work explores the impact of globalisation on the ways in which social workers currently experience their roles and develop their sense of professional identity.
6
Becirovic, Ema. "On Social Choice in Social Networks". Thesis, Linköpings universitet, Kommunikationssystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138578.
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Kollektiva beslut blir en del av vardagen när grupper av människor står inför val. Vi anpassar ofta våra personliga övertygelser med hänsyn till våra vänner. Vi är naturligt beroende av lyckan hos dem som står oss nära. I det här exjobbet undersöker vi en befintlig empatimodell som används för att välja en vinnare från en uppsättning alternativ genom att använda poängbaserade omröstningsprocedurer. Vi visar att en liten modifikation av modellen är tillräcklig för att kunna använda överlägsna omröstningsprocedurer som bygger på parvisa jämförelser av alternativen. Sammanfattningsvis visar vi att det i grunden inte finns någon anledning att använda poängbaserade omröstningsprocedurer i de föreslagna modellerna, eftersom ett mer önskvärt resultat uppnås genom att använda de överlägsna omröstningsprocedurerna.Social choice becomes a part of everyday life when groups of people are faced with decisions to make. We often adjust our personal beliefs with the respect to our friends. We are inherently dependent on the happiness of those near us. In this thesis, we investigate an existing empathy model that is used to select a winner in a set of alternatives by using scoring winner selection methods. We show that a slight modification of the model is enough to be able to use superior winner selection methods that are based on pairwise comparisons of alternatives. We show that there is essentially no reason to use scoring winner selection methods in the models proposed as a more desirable result is achieved by using superior winner selection methods.
7
Vallapu, Sai Krishna. "Towards Network False Identity Detection in Online Social Networks". Thesis, Southern Illinois University at Edwardsville, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10246101.
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In this research, we focus on identifying false identities in social networks. We performed a detailed study on different string matching techniques to identify user profiles with real or fake identity. In this thesis, we focus on a specific case study on sex offenders. Sex offenders are not supposed to be online on social networking sites in few states. To identify the existence of offenders in social networks, we ran experiments to compare datasets downloaded from Facebook and offender registries. To identify the most suitable string matching technique to solve this particular problem, we performed experiments on various methods and utilized the most appropriate technique, the Jaro-Winkler algorithm. The major contribution of our research is a weight based scoring function that is capable of identifying user records with full or partial data revealed in social networks. Based on our data samples created using metadata information of Facebook, we were able to identify the sex offender profiles with real identity and seventy percent of the sex offenders with partial information.
8
You, Bo. "Hub-Network for Distance Computation in Large Social Networks". Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1412601464.
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Bodriagov, Oleksandr. "Social Networks and Privacy". Licentiate thesis, KTH, Teoretisk datalogi, TCS, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166818.
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Centralized online social networks pose a threat to their users’ privacy as social network providers have unlimited access to users’ data. Decentralized social networks address this problem by getting rid of the provider and giving control to the users themselves, meaning that only the end-users themselves should be able to control access of other parties to their data. While there have been several proposals and advances in the development of privacy- preserving decentralized social networks, the goal of secure, efficient, and available social network in a decentralized setting has not been fully achieved. This thesis contributes to the research in the field of security for social networks with focus on decentralized social networks. It studies encryption-based access control and man- agement of cryptographic keys/credentials (required for this access control) via user accounts with password-based login in decentralized social networks. First, this thesis explores the requirements of encryption for decentralized social networks and proposes a list of criteria for evaluation that is then used to assess existing encryption- based access control systems. We find that all of them provide confidentiality guarantees (of the content itself), while privacy (of information about the content or access policies) is either not addressed at all or it is addressed at the expense of system’s performance and flexibility. We highlight the potential of two classes of privacy preserving schemes in the decen- tralized online social network (DOSN) context: broadcast encryption schemes with hidden access structures and predicate encryption (PE) schemes, and propose to use them. Both of these classes contain schemes that exhibit desirable properties and better fulfill the criteria. Second, the thesis analyses predicate encryption and adapts it to the DOSN context as it is too expensive to use out of the box. We propose a univariate polynomial construction for access policies in PE that drastically increases performance of the scheme but leaks some part of the access policy to users with access rights. We utilize Bloom filters as a means of decreasing decryption time and indicate objects that can be decrypted by a particular user. The thesis demonstrates that adapted scheme shows good performance and thus user experience by making a newsfeed assembly experiment. Third, the thesis presents a solution to the problem of management of cryptographic keys for authentication and communication between users in decentralized online social networks. We propose a password-based login procedure for the peer-to-peer (P2P) setting that allows a user who passes authentication to recover a set of cryptographic keys required for the application. In addition to password logins, we also present supporting protocols to provide functionality related to password logins, such as remembered logins, password change, and recovery of the forgotten password. The combination of these protocols allows emulating password logins in centralized systems. The results of performance evaluation indicate that time required for logging in operation is within acceptable bounds.Centraliserade sociala online nätverk utgör ett hot mot användarnas integritet. Detta eftersom leverantörer av sociala nätverkstjänster har obegränsad tillgång till användarnas information. Decentraliserade sociala nätverk löser integritetsproblemet genom att eliminera leverantörer och ge användarna kontroll över deras data. Innebörden av detta är att användarna själva får bestämma vem som får tillgång till deras data. Även om det finns flera förslag och vissa framsteg i utvecklingen avseende integritetsbevarande decentraliserade sociala nätverk, har målet om säkra, effektiva, och tillgängliga sociala nätverk i en decentraliserad miljö inte uppnåtts fullt ut. Denna avhandling bidrar till forskning inom säkerhet avseende sociala nätverk med fokus på decentraliserade sociala nätverk. Avhandlingen inriktas på krypteringsbaserad åtkomstkontroll och hantering av kryptografiska nycklar (som krävs för denna åtkomstkontroll) med hjälp av användarkonton med lösenordsbaserad inloggning i decentraliserade sociala nätverk. Först undersöker denna avhandling krav på kryptering för decentraliserade sociala nätverk och föreslår utvärderingskriterier. Dessa utvärderingskriterier används sedan för bedömning av befintliga krypteringsbaserade system för åtkomstkontroll. Vår utredning visar att samtliga garanterar sekretess av själva innehållet. Integritet av information om innehållet eller åtkomstprinciper är dock inte skyddat alls, alternativt skyddade på bekostnad av systemets prestanda och flexibilitet. Vi lyfter fram potentialen i två klasser av integritetsbevarande system i DOSN sammanhang: broadcast-krypteringssystem med dolda tillgångsstrukturer och predikat krypteringssystem; vi föreslår användning av dessa system. Båda dessa klasser innehåller system som uppvisar önskvärda egenskaper och uppfyller kriterier på ett bättre sätt. För det andra analyserar avhandlingen predikat kryptering och anpassar denna till DOSN sammanhang, eftersom det är för dyrt att använda som det är. Vi föreslår en ”univariate polynomial construction” för åtkomstprinciper i predikat kryptering som drastiskt ökar systemets prestanda, men läcker någon del av åtkomstprincipen till användare med åtkomsträttigheter. Vi använder Bloom-filter för att minska dekrypteringstiden och indikera objekt som kan dekrypteras av en viss användare. Genom att göra ett experiment med nyhetsflödessammansättning visas att det anpassade systemet ger goda resultat och därmed användarupplevelse. För det tredje presenterar avhandlingen en lösning på problemet avseende hanteringen av kryptografiska nycklar för autentisering och kommunikation mellan användare i decentraliserade sociala online nätverk. Vi föreslår en lösenordsbaserad inloggningsprocedur för peer-to-peer (P2P) miljön, som gör att användaren som passerar autentisering får återvinna en uppsättning kryptografiska nycklar som krävs för applikationen. Förutom lösenordsinloggning presenterar vi också stödprotokoll för att ge relaterat funktionalitet, såsom inloggning med lagrade lösenord, lösenordsbyte, och återställning av bortglömda lösenord. Kombinationen av dessa protokoll tillåter simulera lösenordsinloggning i centraliserade system. Prestandautvärderingen visar att tiden som krävs för inloggning är inom acceptabla gränser.
QC 20150602
10
Ammar, Ammar (Ammar T. ). "Search using social networks". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62635.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 59-61).
In this thesis, we present an approach to the problem of personalized web search which makes use of the searcher's social network, in addition to the hyper-link based score used in most search engines. This combination of social and absolute search scores aims to improve the visibility of information that is relevant to the searcher, while maintaining any absolute measures of document importance . In our approach we adopt a flexible framework for combining information from different sources using Rank Aggregation techniques. Our search system, implemented using Java and Python, covers all the events and web pages present on MIT owned websites. We discuss the theory, design,and implementation of this system in details.
by Ammar Ammar.
M.Eng.
11
Hague, Thomas. "Social Networks and Innovation". Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1328.
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This paper investigates how social networks act as catalysts for innovation. It borrows a model for understanding how interaction between heterogeneous social networks catalyzes innovation. Using this model, it then examines historical and contemporary catalysts of innovation and invention within cities. Industry diversity, a measure representing the existence of multiple overlapping domains, is hypothesized to be positively correlated with the number of patents filed within a city per year. Using this analysis of both Renaissance Florence and contemporary metropolitan areas, the paper hopes to demonstrate social influences on innovation.
12
Huang, Yongjian. "Supporting meaningful social networks". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/69844/.
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Recent years have seen exponential growth of social network sites (SNSs) such as Friendster, MySpace and Facebook. SNSs flatten the real-world social network by making personal information and social structure visible to users outside the ego-centric networks. They provide a new basis of trust and credibility upon the Internet and Web infrastructure for users to communicate and share information. For the vast majority of social networks, it takes only a few clicks to befriend other members. People's dynamic ever-changing real-world connections are translated to static links which, once formed, are permanent -- thus entailing zero maintenance. The existence of static links as public exhibition of private connections causes the problem of friendship inflation, which refers to the online practice that users will usually acquire much more ``friends'' on SNSs than they can actually maintain in the real world. There is mounting evidence both in social science and statistical analysis to support the idea that there has been an inflated number of digital friendship connections on most SNSs. The theory of friendship inflation is also evidenced by our nearly 3-year observation on Facebook users in the University of Southampton. Friendship inflation can devalue the social graph and eventually lead to the decline of a social network site. From Sixdegrees.com to Facebook.com, there have been rise and fall of many social networks. We argue that friendship inflation is one of the main forces driving this move. Despite the gravity of the issue, there is surprisingly little academic research carried out to address the problems. The thesis proposes a novel algorithm, called ActiveLink, to identify meaningful online social connections. The innovation of the algorithm lies in the combination of preferential attachment and assortativity. The algorithm can identify long-range connections which may not be captured by simple reciprocity algorithms. We have tested the key ideas of the algorithms on the data set of 22,553 Facebook users in the network of University of Southampton. To better support the development of SNSs, we discuss an SNS model called RealSpace, a social network architecture based on active links. The system introduces three other algorithms: social connectivity, proximity index and community structure detection. Finally, we look at the problems relating to improving the network model and social network systems.
13
Shaikh, Sajid S. "COMPUTATION IN SOCIAL NETWORKS". Kent State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1185560088.
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Gamal, Doaa. "Social Networks Influence Analysis". UNF Digital Commons, 2017. http://digitalcommons.unf.edu/etd/723.
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Pew Research Center estimates that as of 2014, 74% of the Internet Users used social media, i.e., more than 2.4 billion users. With the growing popularity of social media where Internet users exchange their opinions on many things including their daily life encounters, it is not surprising that many organizations are interested in learning what users say about their products and services. To be able to play a proactive role in steering what user’s say, many organizations have engaged in efforts aiming at identifying efficient ways of marketing certain products and services, and making sure user reviews are somewhat favorable. Favorable reviews are typically achieved through identifying users on social networks who have a strong influence power over a large number of other users, i.e. influential users.
Twitter has emerged as one of the prominent social network services with 320 million monthly active users worldwide. Based on the literature, influential Twitter users have been typically analyzed using the following three models: topic-based model, topology-based model, and user characteristics-based model. The topology-based model is criticized for being static, i.e., it does not adapt to the social network changes such as user’s new posts, or new relationships. The user characteristics-based model was presented as an alternative approach; however, it was criticized for discounting the impact of interactions between users, and users’ interests. Lastly, the topic-based model, while sensitive to users’ interests, typically suffers from ignoring the inclusion of inter-user interactions.
This thesis research introduces a dynamic, comprehensive and topic-sensitive approach for identifying social network influencers leveraging the strengths of the aforementioned models. Three separate experiments were conducted to evaluate the new approach using the information diffusion measure. In these experiments, software was developed to capture users’ tweets pertinent to a topic over a period of time, and store the tweet’s metadata in a relational database. A graph representing users was extracted from the database. The new approach was applied to the users’ graph to compute an influence score for each user.
Results show that the new composite influence score is more accurate in comprehensively identifying true influential users, when compared to scores calculated using the characteristics-based, topic-based, and topology-based models. Also, this research shows that the new approach could leverage a variety of machine learning algorithms to accurately identify influencers.
Last, while the focus of this research was on Twitter, our approach may be applicable to other social networks and micro-blogging services.
15
Fracassi, Cesare. "Social networks and finance". Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1872060441&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Bolletta, Ugo <1986>. "Social Influence in Networks". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7332/1/Bolletta_Ugo_Tesi.pdf.
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This thesis is composed by three standalone papers. The first chapter is about opinion formation processes. Individuals influence each other according to the network structure. If the network is connected and satisfies other mild assumptions, the society will reach a
consensus. Therefore, it is a matter of interest understanding when the network would be connected
or not. Here, we develop a model where the network takes place endogenously, and agents update
their opinions accordingly. We study general conditions on the initial distribution of opinions
such that consensus will be reached. We provide sufficient conditions for connectedness. In the dynamic model we show that polarization both in the transition and the long run. This essay is a joint work with Paolo Pin (Bocconi University). The second chapter is about
peer effects. I consider how social pressure affects the strategic network formation process. Agents
choose their links subject to mutual consent, and then equilibrium behaviors are determined by an
underlying game where agents choose their effort. I provide a characterization
result for all pairwise Nash stable network, and use farsightedness to avoid cycles. As an
application, I consider peer effects in the classroom. Results suggest that we could set
optimal policies to improve outcome of low achievement students through targeted incentives
schemes. In the last chapter I focus on the interaction between real and virtual life. To do so I
propose a model of search where agents choose in equilibrium how intense is their on-line
activity. The outcomes of the game depend on the network, which takes place through a
semi-random process. I extend the standard random network formation allowing agents to hold a
certain degree of choice. The model allows to track characteristics on the meeting environment and individual preferences that would make virtual and real life substitutes or complements.
17
Rancan, Michela. "Social Networks in Finance". Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3427391.
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The main purpose of the present thesis is to shed light on the role of social networks in finance. The interest in this subject is motivated by the fact that social networks influence beliefs, choices and behaviors of agents. Moreover, nowadays financial markets are increasingly interdependent and financial actors are highly interconnected. Nevertheless, according with a traditional approach competition is a standard assumption modelling financial markets. Hence, this work was inspired by the scientific curiosity to investigate whether social interactions may be a channel of information exchange even in a financial context, if the financial choices can be influenced by networks and, what are the implications of social networks in finance.
In an attempt to answer these questions, we exploit the investment behaviors of U.S. mutual funds and the networks of their managers (defined using managers' biographical information).
More precisely, the first chapter is an introduction to social network: we briefly review the recent literature about this topic in finance and we discuss some challenges of these applications.
The second chapter explores whether the trading behaviors of fund managers are influenced by the behaviors of other managers belonging to the same social network (managers who have attended the same university). According to our results a manager is more likely to buy/sell a particular stock in any quarter if managers who belong to the same network do that. The effect turns out to be stronger when we restrict the group to managers graduated in the same year. Such results can be interpreted by the "word of mouth effect". Other explanations such as same training or socio-economic backgrounds are possible.
Finally, the third chapter investigates the effect of social networks on mutual funds performance. We take advantage of the recent advances in the theoretical and methodological tools provided by social network analysis to examine the network properties. We find that managers' network have all the properties of a small world (as defined by Watts and Strogatz, 1998). Consistent with this, we provide empirical evidence that performance is higher for fund managers with many connections and if they are in a good network position.Lo scopo principale di questa tesi è quello di approfondire il ruolo dei network sociali in finanza. L'interesse per questa tematica nasce dal fatto che i network sociali influenzano opinioni, scelte e comportamenti degli agenti. Non solo, i mercati finanziari oggigiorno sono sempre più interdipendenti e gli agenti che vi operano fortemente interconnessi. Tuttavia nell'approcio tradizionale la competizione è sempre stata un'assunzione standard nei modelli di mercati finanziari. Pertanto, questo lavoro è stato ispirato dalla curiosità scientifica di studiare se l'interazione sociale possa essere un canale di scambio di informazioni anche in ambito finaziario, se le scelte finanziarie possano essere influenzate dai network e più in generale quali possano essere le implicazioni dei network sociali in finanza. Nel tentativo di dare una prima risposta a queste domande si è utilizzato un campione di fondi di investimento americani e i network dei manager che gestiscono tali fondi (definiti in base a informazioni bibliografiche). Più precisamente nel primo capitolo si è introdotto il tema dei social network, discutendo la recente letteratura che in finanza si è occupata di tale argomento e menzionando alcune difficoltà applicative. Nel secondo capitolo si è analizzato se le scelte di investimento dei manager dei fondi di investimento siano influenzati dai comportamenti di investimento di altri manager appartenenti allo stesso network sociale (ovvero manager che si sono laureati presso la stessa università). I risultati hanno evidenziato che un manager ha maggior probabilità di comprare/vendere una determinata azione in un determinato trimestre se i manager del suo stesso network hanno fatto la medesima scelta di investimento. Questo effetto è più marcato quando la definizione di network si riferisce sia all'università frequentata che all'anno di conseguimento della laurea. Questi risultati possono essere spiegati dal fatto che manager dello stesso network si siano scambiati informazioni, oppure dal fatto di aver ricevuto la stessa formazione accaddemica o aver vissuto nel medesimo contesto socio-economico. Infine, nel terzo capitolo, si è studiato l'effetto del network sociale sulle performance dei fondi di investimento. Lo studio delle proprietà dei network, mediante l'utilizzo della social network analysis, mostra che i network dei manager dei fondi di investimento, costruiti mediante le informazioni sulla formazione universitaria, hanno tutte le caratteristiche di un small world (secondo la definizione di Watts and Strogatz, 1998). In linea con questo risultato l'analisi empirica ha mostrato come le performance dei fondi sono significativamente più elevate quando i manager dei fondi hanno molte conessioni e una buona posizione nel network.
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Burks, Stephen D. "Social Networks and Its Uses in Collaborative Strategies". Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5094.
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In this paper, there are three policy scenarios that are explored and discussed. The
first scenario comes from a dataset where little information is known about individual nodes and connection weights are placed based on the economic theory of increasing or constant returns. The second dataset was derived by taking a group of academic researchers (without any knowledge beyond co authorship alliances)
working on a joint venture and exploring what combined research ventures would be
most beneficial for future research outputs. More information concerning individual
nodes and connections is given in this dataset, but the weights on connections are still developed according to rules of economic theory. The final set of data is developed by
viewing the same co-authorship alliances as in the second scenario, but instead the data is
examined more thoroughly and more accurate maps of authors connection weights are
generated.
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Nguyen, Nguyet Minh. "SNbR : Social Networks-based Forwarding in Delay Tolerant Networks". Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42275.
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Recently, Web 2.0 has become very popular with the appearance of many social networks web sites such as Facebook, Google+, YouTube, Flickr, etc., which allow users to create and share contents. Besides Web 2.0, mobile networks have also become more popular than ever with the increasing popularity and diversity of mobile devices. Users of mobile devices also have the desire to connect and share their own contents everywhere and at any time. Supporting communications in mobile networks becomes an interesting research area which has attracted much attention of the research community in recent years. In the direction of investigating the application of social networks in supporting the communications in delay tolerant networks which are formed among mobile devices, in this thesis we propose a novel message forwarding method, called Social Networks-based Forwarding (SNbR), in DTNs which utilizes social networks among mobile users and the context of node relationships to facilitate the communications between mobile devices. Simulations in the scenario of a city with the working day movement model have shown that our proposed method achieves a better performance in terms of delivery ratio against delivery cost compared to many previous methods.
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DeBusk, Kendra Portia Adrienne Howard. "Emotional intelligence, personality, social networks, and social perception". Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3452.
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Emotional Intelligence (EI) is a relatively new concept in the field of psychology, introduced by Salovey and Mayer in 1990. Research on EI has found associations among EI and social network size, health and well-being, and job performance.(Austin, Saklofske, & Egan, 2003; Brackett, Mayer, & Warner, 2003; Petrides & Furnham, 2003; Saklofske, Austin, & Minski, 2001). Two different types of EI, trait EI and ability EI, have been identified in the literature. Trait EI was identified by Petrides and Furnham, and is a non-cognitive ability which allows an individual to regulate his/her mood, recognize and make the most of emotions, and utilize social skills, and is measured by self report. Ability EI is the ability of an individual to understand, generate, and manage emotions. Ability EI is measured using a performance measure which assesses the capacity of an individual to perceive emotions in him/herself, others, and the environment. Emotional intelligence has been linked to aspects of well-being, such as social network quality. In order to examine how EI related to social networks, both trait and ability EI were measured along with the Big Five factors of personality and social network quality and size. A study of 268 participants investigated the relationships amongst trait EI, personality, and social network quality and size. The Big Five factors of personality were all significantly positively correlated with EI (p< .01), and were also significantly correlated with social network quality and size. EI was significantly related to social network quality and size. When controlling for personality, EI was no longer significantly correlated with any of the social network quality or size variables. A subset of participants (n=78) completed an ability measure of EI, the Mayer Salovey Caruso Emotional Intelligence Test (MSCEIT). There were no significant correlations between MSCEIT scores and any of the other variables. A follow-up study was then carried out looking at the relationship of the original study variables with ability EI (MSCEIT), life stress, measured using the Uplifts and Hassles scale, and depression, measured using the Beck Depression Inventory (BDI), in the original participants. The results from this study indicated that emotional stability was significantly correlated with the Uplifts portion of the life stress scale, but not with Hassles. Conscientiousness was significantly negatively correlated with both the Hassle subscale of life stress and the BDI score. Emotional stability was also significantly negatively correlated with the BDI score. The total ability EI score measured by the MSCEIT did not show significant relationships with any other variables. Given that EI has been linked to social network quality and size, and one of the facets of EI is the capacity of an individual to recognize emotions in others, it would seem that individuals who are high in EI should have larger and better quality social networks as they are theoretically able to recognize and appropriately respond to the emotions of others. In order to test this, a social perception inspection time task was carried out in which participants were required to identify if a face was happy, sad, or angry. The faces used were both Caucasian and Far-East Asian, the hypothesis being that a person high in EI would recognize the facially expressed emotions regardless of whether the face shown was of their own race or not. Results from this study indicated that EI was not related to correctly identifying facial expressions. The results of these studies are discussed along with suggestions for future research in this area.
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Johnson, Cathleen A. "Social Capital and Conventions: A Social Networks Perspective". Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/27230.
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We introduce a spatial cost topology in the network formation model analyzed by Jackson and Wolinsky, Journal of Economic Theory 71 (1996), 44--74. This cost topology might represent geographical, social, or individual differences. It describes variable costs of establishing social network connections. Participants form links based on a cost-benefit analysis. We examine the pairwise stable networks within this spatial environment. Incentives vary enough to show a rich pattern of emerging behavior. We also investigate the subgame perfect implementation of pairwise stable and efficient networks. We construct a multistage extensive form game that describes the formation of links in our spatial environment. Finally, we identify the conditions under which the subgame perfect Nash equilibria of these network formation games are stable.
We analyze the dynamic implications of learning in a large population coordination game where both the actions of the players and the communication network evolve over time. Cost considerations of social interaction are incorporated by considering a circular model with endogenous neighborhoods, meaning that the locations of the players are fixed but players can create their own communication network.The dynamic process describing medium-run behavior is shown to converge to an absorbing state, which may be characterized by coexistence of conventions. In the long run, when mistake probabilities are small but nonvanishing, coexistence of conventions is no longer sustainable as the risk-dominant convention becomes the unique stochastically stable state.
We create and investigate a system that is capable of observing the accumulation of social capital and the effect of social capital accumulation on behavior of individually rational players. In the first model, we develop a restricted system to show that social capital forms and is maintained at a steady state level. The resulting network is the chain. The second model uses a congestion function in conjunction with social capital to show a network emerge that contains links that costlier than those in the chain network.Ph. D.
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ATHANASIOU, THOMAS. "Multi-dimensional analysis of social multi-networks : Analysing a 5-layer social network case study". Thesis, Uppsala universitet, Institutionen för informatik och media, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-273908.
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Network theory analysis is applicable to many scientific disciplines (fields) such as biology, statistics and sociology. The social network analysis is one of the various branches of the broader network theory analysis, the social network analysis. It is of high interest among the researchers in social sciences. Social networks have had a significant impact on human civilizations for many centuries. During the last two decades, the main academic interest was addressed towards the research and analysis of a dynamically uprising sector of social networks, the on-line networks, primarily due to the domination of the Internet and technology over human attitudes and relations in modern societies. For many years, research was emphasized on the analysis of simple social networks, whilst during the last decade several researchers started working on the analysis of more complicated social networks, which consist by several smaller social networks. There are important differences between mono and multi-dimensional network analysis. Mono-dimensional analysis provides the research with relevant knowledge. On the other hand, multi-dimensional analysis is still at initial stage. As a result, several potential models related to the multi-networks analysis cannot always provide reliable and adequate outcomes. However, due to the fact that different social networks can be easily combined and form more extended and complicated networks, it is of high importance for the researchers to advance the multi-dimensional analysis and provide more adequate analytical models. The purpose of this thesis is to present the dynamic of the multi-dimensional analysis by consecutively applying both mono and multi-dimensional analysis on a social multi-network. The findings suggest that multi-dimensional analysis can add reliable knowledge on the social network analysis, but many problems that arose due the complexity of the multi-networks structures need to be addressed.
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Broccatelli, Chiara. "Going beyond secrecy : methodological advances for two-mode temporal criminal networks with Social Network Analysis". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/going-beyond-secrecy-methodological-advances-for-twomode-temporal-criminal-networks-with-social-network-analysis(f0f91f79-7bc3-442c-a16b-e9cf44cc68c3).html.
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This thesis seeks to extend the application of Social Network Analysis (SNA) to temporal graphs, in particular providing new insights for the understanding of covert networks. The analyses undertaken reveal informative features and properties of individuals' affiliations under covertness that also illustrate how both individuals and events influence the network structure. The review of the literature on covert networks provided in the initial two chapters suggests the presence of some ambiguities concerning how authors define structural properties and dynamics of covert networks. Authors sometimes disagree and use their findings to explain opposite views about covert networks. The controversy in the field is used as a starting point in order to justify the methodological application of SNA to understand how individuals involved in criminal and illegal activities interact with each other. I attempt to use a deductive approach, without preconceived notions about covert network characteristics. In particular, I avoid considering covert networks as organisations in themselves or as cohesive groups. I focus on individuals and their linkages constructed from their common participation in illicit events such as secret meetings, bombing attacks and criminal operations. In order to tackle these processes I developed innovative methods for investigating criminals' behaviours over time and their willingness to exchange tacit information. The strategy implies the formulation of a network model in order to represent and incorporate in a graph three types of information: individuals, events, and the temporal dimension of events. The inclusion of the temporal dimension offers the possibility of adopting a more comprehensive theoretical framework for considering individuals and event affiliations. This thesis expands the analysis of bipartite covert networks by adopting several avenues to explore in this perspective. Chapter 3 proposes a different way to represent two-mode networks starting from the use of line-graphs, namely the bi-dynamic line-graph data representation (BDLG), through which it is possible to represent the temporal evolution of individual's trajectories. The following chapter 4 presents some reflections about the idea of cohesion and cohesive subgroups specific to the case of two-mode networks. Based on the affiliation matrices, the analysis of local clustering through bi-cliques offers an attempt to analyse the mechanism of selecting accomplices while taking into account time. Chapter 5 is concerned with the concept of centrality of individuals involved in flows of knowledge exchanges. The theoretical and analytical framework helps in elaborating how individuals share their acquired hands-on experiences with others by attending joint task activities over time. Chapter 6 provides an application of the approaches introduced in the preceding chapters to the specific case of the Noordin Top terrorist network. Here, the knowledge of experience flow centrality measure opens up a new way to quantify the transmission of information and investigate the formation of the criminal capital. Finally, the last Chapter 7 presents some future research extensions by illustrating the versatility of the proposed approaches in order to provide new insights for the understanding of criminals' behaviours.
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Anderson, Jonathan. "Privacy engineering for social networks". Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/244239.
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In this dissertation, I enumerate several privacy problems in online social networks (OSNs) and describe a system called Footlights that addresses them. Footlights is a platform for distributed social applications that allows users to control the sharing of private information. It is designed to compete with the performance of today's centralised OSNs, but it does not trust centralised infrastructure to enforce security properties. Based on several socio-technical scenarios, I extract concrete technical problems to be solved and show how the existing research literature does not solve them. Addressing these problems fully would fundamentally change users' interactions with OSNs, providing real control over online sharing. I also demonstrate that today's OSNs do not provide this control: both user data and the social graph are vulnerable to practical privacy attacks. Footlights' storage substrate provides private, scalable, sharable storage using untrusted servers. Under realistic assumptions, the direct cost of operating this storage system is less than one US dollar per user-year. It is the foundation for a practical shared filesystem, a perfectly unobservable communications channel and a distributed application platform. The Footlights application platform allows third-party developers to write social applications without direct access to users' private data. Applications run in a confined environment with a private-by-default security model: applications can only access user information with explicit user consent. I demonstrate that practical applications can be written on this platform. The security of Footlights user data is based on public-key cryptography, but users are able to log in to the system without carrying a private key on a hardware token. Instead, users authenticate to a set of authentication agents using a weak secret such as a user-chosen password or randomly-assigned 4-digit number. The protocol is designed to be secure even in the face of malicious authentication agents.
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Galeotti, Andrea. "On social and economic networks". [Amsterdam] : Rotterdam : Thela Thesis ; Erasmus University [Host], 2005. http://hdl.handle.net/1765/1920.
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Cano, Daniel Ramirez. "Opinion formation in social networks". Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540688.
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Kestner, John Anthony. "Social networks for lonely objects". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62077.
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Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 115-119).
Visions of ubiquitous computing describe a network of devices that quietly supports human goals, but this may also add complexity to an already frustrating relationship between humans and their electronic objects. As we move from vision to reality, there is an opportunity to rethink how we interact with our objects and networks of objects, and close the communication gap between man and machine. 'This thesis defines social and super-mechanical affordances for products which may consist of many physical and digital objects. These new objects will not look like stripped-down contemporary computers, but augmented ordinary objects that are focused on input and output, exposed on Twitter. Apps in the cloud use Twitter to marshall the appropriate objects to execute human tasks. Using a social network as transport allows apps and their owners to manage a large network of computing objects with the same constructs that we use to manage many human relationships. From this direction, we take a step toward a consumer-amenable implementation of ubiquitous computing.
by John Anthony Kestner.
S.M.
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Campbell, Arthur (Arthur Donald). "Social networks in industrial organization". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/49714.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2009.Includes bibliographical references (p. 141-145).
Chapter 1 studies the optimal strategies of a monopolist selling a good to consumers who engage in word of mouth communication. The monopolist uses the price it charges to influence both the proportion of the population that is willing to purchase the good and the pattern of communication that takes place within the social network. I find a number of results: (i) demand is more elastic in the presence of word of mouth; (ii) the monopolist reduces the price to induce additional word of mouth for regular goods, however for goods whose valuation is greater for well connected individuals the price may, in fact, be greater; (iii) the optimal pattern of diffusion involves introductory prices which vary up and down; and (iv) exclusive (high priced) products will optimally target advertising towards individuals with many friends whereas common (low priced) products will target individuals with fewer friends. Chapter 2 presents a model of friendship formation in a social network. During each period a new player enters the social network, this player searches for and forms friendships with the existing population and all individuals play a prisoner's dilemma game with each of their friends. The set of friendships a player forms reveals some information to a friend about how likely she is to subsequently cooperate. Cooperative types are able to separate themselves from uncooperative types by becoming friends with people who know one another.
(cont.) The threat of communication amongst people who know one another prevents an uncooperative type mimicking a cooperative type. Chapter 3 analyzes the effects of policies which support electricity generation from intermittent technologies (wind, solar). I find that intermittent generation is a substitute for baseload technologies but may be complementary or substitutable for peaking/intermediate technologies. I characterize the long run implications of this for carbon emissions.
by Arthur Campbell.
Ph.D.
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Borzino, Natalia. "Networks, social information and compliance". Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/64224/.
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The work developed in my PhD on “Networks, Social Information and Compliance” focuses on compliance (voluntary and non), diffusion of information and spillovers in diverse network structures. More specifically, we test experimentally how minimal social information is diffused through different network structures and its role on increasing the level of efficiency along with its positive effect on voluntary compliance of emergent social norms and tax compliance. In the first two chapters, we implement a networked version of the trust game with two senders and one receiver. We manipulate in a minimal way the social information available in the network and, the novelty of our work consists in the introduction of non-binding suggestion about the level of trust and trustworthiness, which is totally fair and (partially) efficient. It is also manipulated in the two studies the selection mechanism of the roles in the game by introducing social status. Our findings suggest that social information has a positive and significant effect on increasing the level of trust in the network. The non-binding suggestion has also a positive and significant effect on individual decisions. In the last chapter, we study in a laboratory experiment how tax compliance information is diffused in a fixed-six-nodes circle network. The game has four information conditions: No Info, Full Info, Positive Info and Negative Info. In the No info treatment, subjects get individual information about whether they were audited, the outcome of it and her final payoff. In the Positive Info (Negative Info) treatment, participants get information whether adjacent connected nodes were audited and found compliant (noncompliant). In the Full Info, participants get both positive and negative signals. We control for the effect of signals on participants’ beliefs on the ex-ante fixed and unknown audit probability by an incentive compatible mechanism. The tax rate and fine rate are fixed and known by the subjects. Our findings suggest that positive and negative signals have a significant effect in the levels of reporting and compliance at individual level. Indeed, diffusion of non-strong negative signal (one bad example) has a negative effect on individuals’ tax compliance. The diffusion of strong positive signals (two good examples) is required to generate any increase in compliance decisions within networks.
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Brito, José Francisco Mendes de. "Behavior modeling in social networks". Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11674.
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Mestrado em Engenharia de Computadores e TelemáticaAs redes sociais têm tido um crescimento viral nos últimos anos. No início do século XXI já se discutia a indispensabilidade da Internet e no presente, as redes sociais reforçam ainda mais esta ideia. O ser humano, ao longo da sua história, foi mostrando a necessidade de exprimir as suas ideias, os seus pensamentos, as suas alegrias, as suas tristezas… As redes sociais são assim um espaço onde as pessoas, de diferentes idades ou culturas, podem partilhar os seus pensamentos e experiências. As redes sociais são desta forma um espaço apetecível para todo o tipo de ataques informáticos, especialmente de phishing. Nesta dissertação faz-se uma análise de diferentes redes sociais, das suas APIs e das formas de extrair informação das mesmas, dando especial enfâse ao Facebook. Como tal, foi desenvolvido uma ferramenta que utiliza esta informação e que permite monitorizar o comportamento de um utilizador, permitindo a verificação da legitimidade do seu comportamento. Neste projeto foi utilizada a Graph API do Facebook, que se trata de uma API baseada no protocolo HTTP e que permite aceder à estrutura social (Social Graph) do Facebook, retornando os dados no formato JSON. Para fazer a ligação ao Facebook foi utilizado o Facebook PHP SDK. O script utilizado é independente do website e guarda toda a informação em JSON, estando os ficheiros organizados por tipo de conteúdo e pelo ID do utilizador. Desta forma o script pode ser facilmente reutilizado para outro tipo de ferramentas online ou offline.
Social networks are having a viral growth in recent years. The vital importance of the Internet has been under discussion since the beginning of the 21st century and social networks are reinforcing this idea. The human being, throughout its history, has been showing the need to express their ideas, their thoughts, their joys, their sorrows ... Social networks become then a tool which people, of different ages and cultures, can use for sharing their thoughts and experiences. Social networks are an attractive place to all kinds of cyber-attacks, especially phishing. This dissertation analyzes different social networks, their APIs and how to extract information from them, giving more emphasis to Facebook. As such, a website was developed that uses this information and transforms it into a tool that allows users to monitor their behavior and to verify if it is legitimate. In this model we used the Facebook Graph API, which is an HTTP based API that allows access to the Facebook Social Graph, returning data in JSON format. To connect to Facebook, the Facebook PHP SDK was used. The script is independent from the website and keeps all the information in JSON files that are organized by content type and user ID. In this manner, the script can be easily reused for other type of tools, online or offline.
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Hilton, Kristina B. "Dynamics of Multicultural Social Networks". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6711.
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Historically human endeavors around the globe are in search of bilateral relationships. Knowledge and commerce has played a very significant role in increasing the ability for humans to connect for the betterment of the human species. As the means of communication improve, mutual benefits to the community as a whole also increase. Moreover, the benefits are filtered down to members of the overall community. Recent advancement in electronic communication technologies and in knowledge, in particular, physical, chemical, engineering and medical sciences and philosophies, have facilitated nearly instantaneous multi-cultural interactions. Local problems and solutions have become global. This has generated a need for cooperation, coordination, and co-management at local and global levels. This instant communication and easy access to almost all members of the global community, with minimal cost and effort, causes an increase in uncertainty and lack of clarity in communication and misunderstanding between the members of the community. This leads to a fuzzy and stochastic environment. In short, the 21st century has seen a significant increase in the need to consider all human endeavors as being subject to random environmental fluctuations.
More precisely, currently the human species is highly mobile. In this work, an attempt is made (1) to balance communities working cooperatively and cohesively with one another while preserving member ability to retain individuality and fostering an environment of cultural state diversity. We develop (2) constructive analytic algorithms that provide tools to study qualitative and quantitative properties of multicultural diverse dynamic social networks. Under network parametric space/set conditions (3) cohesion and co-existence of members of multicultural dynamic network are insured. The parametric conditions (4) are algebraically simple, easy to verify, and robust. Moreover, the presented study of parametric representations of cohesion, co-existence and consensus attributes and robustness of multicultural dynamic networks provides a quantitative tool for planning, policy and performance of human mobility processes for members of a multicultural dynamic network.
We develop and investigate (5) a deterministic dynamic multicultural network. To exhibit the significance of the analysis, ideas, the complexity and limitations, we present a specific prototype model. This serves to establish the framework for finding explicit sufficient conditions in terms of system parameters for studying a complex dynamic network. Further, we decompose the cultural state domain into invariant subsets (6) and consider the behavior of members within each cultural state subset. Moreover, we analyze the relative cultural affinity between individual members relative to the center of the social network. We then (7) outline the general method for investigating a multicultural cultural network. We also demonstrate the degree of conservatism of the estimates using Euler type numerical approximation schemes. We are then able to consider how changes in the various parametric effects are reflected on the dynamics of the network.
The deterministic multicultural dynamic model and analysis is extended (8) to a multicultural dynamic network under random environmental perturbations. We present a detailed prototype model for the purpose of investigation. Introducing the concept of stochastic cohesion and consensus in the context of probabilistic modes of convergence (9), the explicit sufficient conditions in terms of system parameters are given to exhibit the cohesive property of the stochastic network. The effects of random fluctuations are characterized.
We then extend the stochastic model (10) to a multicultural hybrid stochastic dynamic network model. By considering a hybrid dynamic, we can explore the properties of a multicultural dynamic under the influence of both continuous-time and discrete-time cultural dynamic systems. This model captures external influences and internal changes that may have an impact on the members and system parameters of the dynamic network. We extend the ideas of global cohesion and consensus to local cohesion and consensus (11). Again, the detailed study is focused on a prototype hybrid multicultural dynamic network. Using the ideas and tools developed from the stochastic network (12), we are able to establish conditions on the network parameters for which the cultural network is locally cohesive. Using Euler-Maruyama type numerical approximation schemes to model the network, we better understand to what extent the analytically developed estimates are feasible.
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Bergami, Giacomo. "Hypergraph Mining for Social Networks". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7106/.
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Nowadays, more and more data is collected in large amounts, such that the need of studying it both efficiently and profitably is arising; we want to acheive new and significant informations that weren't known before the analysis.
At this time many graph mining algorithms have been developed, but an algebra that could systematically define how to generalize such operations is missing.
In order to propel the development of a such automatic analysis of an algebra, We propose for the first time (to the best of my knowledge) some primitive operators that may be the prelude to the systematical definition of a hypergraph algebra in this regard.
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Chagarlamudi, Venkata. "TEMPORAL CONSIDERATIONS IN SOCIAL NETWORKS". OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/727.
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There are many ways with which we can analyze Dynamic Social Networks. This project summarizes contemporary temporal considerations in social networks. Time accounts for changes in the social networks based on relationships between time vs. data, time vs. relationships, time vs. hierarchies, time vs. behaviors, time vs. density, and time vs. distance. We have observed how time relations, data, behavior will affect network size and density using real time Face book data.
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Klochkov, Yegor. "Modelling Financial and Social Networks". Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20557.
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In dieser Arbeit untersuchen wir einige Möglichkeiten, financial und soziale Netzwerke zu analysieren, ein Thema, das in letzter Zeit in der ökonometrischen Literatur große Beachtung gefunden hat.
Kapitel 2 untersucht den Risiko-Spillover-Effekt über das in White et al. (2015) eingeführte multivariate bedingtes autoregressives Value-at-Risk-Modell. Wir sind an der Anwendung auf nicht stationäre Zeitreihen interessiert und entwickeln einen sequentiellen statistischen Test, welcher das größte verfügbare Homogenitätsintervall auswählt. Unser Ansatz basiert auf der Changepoint-Teststatistik und wir verwenden einen neuartigen Multiplier Bootstrap Ansatz zur Bewertung der kritischen Werte.
In Kapitel 3 konzentrieren wir uns auf soziale Netzwerke. Wir modellieren Interaktionen zwischen Benutzern durch ein Vektor-Autoregressivmodell, das Zhu et al. (2017) folgt. Um für die hohe Dimensionalität kontrollieren, betrachten wir ein Netzwerk, das einerseits von Influencers und Andererseits von Communities gesteuert wird, was uns hilft, den autoregressiven Operator selbst dann abzuschätzen, wenn die Anzahl der aktiven Parameter kleiner als die Stichprobegröße ist.
Kapitel 4 befasst sich mit technischen Tools für die Schätzung des Kovarianzmatrix und Kreuzkovarianzmatrix. Wir entwickeln eine neue Version von der Hanson-Wright- Ungleichung für einen Zufallsvektor mit subgaußschen Komponenten. Ausgehend von unseren Ergebnissen zeigen wir eine Version der dimensionslosen Bernstein-Ungleichung, die für Zufallsmatrizen mit einer subexponentiellen Spektralnorm gilt. Wir wenden diese Ungleichung auf das Problem der Schätzung der Kovarianzmatrix mit fehlenden Beobachtungen an und beweisen eine verbesserte Version des früheren Ergebnisses von (Lounici 2014).In this work we explore some ways of studying financial and social networks, a topic that has recently received tremendous amount of attention in the Econometric literature. Chapter 2 studies risk spillover effect via Multivariate Conditional Autoregressive Value at Risk model introduced in White et al. (2015). We are particularly interested in application to non-stationary time series and develop a sequential test procedure that chooses the largest available interval of homogeneity. Our approach is based on change point test statistics and we use a novel Multiplier Bootstrap approach for the evaluation of critical values. In Chapter 3 we aim at social networks. We model interactions between users through a vector autoregressive model, following Zhu et al. (2017). To cope with high dimensionality we consider a network that is driven by influencers on one side, and communities on the other, which helps us to estimate the autoregressive operator even when the number of active parameters is smaller than the sample size. Chapter 4 is devoted to technical tools related to covariance cross-covariance estimation. We derive uniform versions of the Hanson-Wright inequality for a random vector with independent subgaussian components. The core technique is based on the entropy method combined with truncations of both gradients of functions of interest and of the coordinates itself. We provide several applications of our techniques: we establish a version of the standard Hanson-Wright inequality, which is tighter in some regimes. Extending our results we show a version of the dimension-free matrix Bernstein inequality that holds for random matrices with a subexponential spectral norm. We apply the derived inequality to the problem of covariance estimation with missing observations and prove an improved high probability version of the recent result of Lounici (2014).
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Wood, Samuel Bennett. "Social network coding rate control in information centric delay tolerant networks". Thesis, University of California, Santa Cruz, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1583279.
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Tactical and emergency-response networks require efficient communication without a managed infrastructure in order to meet the requirements of mission critical applications. In these networks, mobility, disruption, limited network resources, and limited host resources are the norm instead of the exception. Despite these constraints, applications must quickly and reliably share data collected from their environment to allow users to coordinate and make critical decisions. Our previous work demonstrates that applying information-centric paradigms to the tactical edge can provide performance benefits over traditional address centric approaches. We expand on this work and investigate how social relationships can be inferred and exploited to improve network performance in volatile networks.
As a result of our investigation, we propose SOCRATIC (SOCial RATe control for Information Centric networks), a novel approach to dissemination that unifies replication and network coding, which takes advantage of social content and context heuristics to improve network performance. SOCRATIC replicates network encoded blocks according to a popularity index metric that captures social relationships, and is shared during neighbor discovery. The number of encoded blocks that is relayed to a node depends on its interest in the data object and its popularity index, i.e., how often and for how long it meets other nodes. We observe that nodes with similar interests tend to be co-located and we exploit this information through use of a generalization of a data object-to-interest matching function that quantifies this similarity. Encoded blocks are subsequently replicated towards the subscriber if a stable path exists. We evaluate an implementation of SOCRATIC through a detailed network emulation of a tactical scenario and demonstrate that it can achieve better performance than the existing socially agnostic approaches.
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Junuthula, Ruthwik Reddy. "Modeling, Evaluation and Analysis of Dynamic Networks for Social Network Analysis". University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1544819215833249.
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Schaefer, Cora. "Personal networks on social network sites (SNS) - Context and personality influences". [S.l. : s.n.], 2008. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000009431.
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Nordvik, Monica K. "Contagious Interactions : Essays on social and epidemiological networks". Doctoral thesis, Stockholm : Visby : Acta Universitatis Stockholmiensis ; eddy.se [distributör], 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8309.
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Birke, Daniel. "Social networks and the economics of networks : how do network effects influence consumer choice in mobile telecommunications?" Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444634.
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Busch, Christian. "Social entrepreneurs as network orchestrators : how and why do social entrepreneurs build up and leverage social networks to perform?" Thesis, London School of Economics and Political Science (University of London), 2013. http://etheses.lse.ac.uk/908/.
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Over the last decades, extensive research about the role of networks in venture creation and development in both the sociology- (e.g.,Burt, 2005; Chiesi, 2007) and management- literature (e.g., Hoang & Antoncic, 2003; Maurer & Ebers, 2006) has been produced. However, while social networks have been recognized as crucial elements for the growth of social ventures (e.g., Bradach, 2010; Waitzer & Paul, 2011), there has been identified a lack of theory-motivated papers on how and why the different dimensions and configurations of social networks influence (social) venture performance over time (Aldrich & Kim,2007; Dacin et al., 2010). Filling this gap, this thesis focuses on the dynamic networking patterns of social ventures over the organizational lifecycle. It consists of three major parts: one conceptual paper, and two empirical papers. Drawing from networks-, social capital-, and organizational ecology-approaches (e.g., Hannan & Freeman, 1989; Kim et al., 2006), in the conceptual paper I develop a four-stage typology of network development, contending that selective boundary-spanning can lead to better performance outcomes if aligned with time-contingencies. The second paper, a comparative case study of six social ventures operating in Kenya’s low income context (a setting neglected by management research), uses a qualitative approach to examine how these ventures orchestrated networks. Via the comparison of success-, failure-, and turnaround- cases, I find four core ‘stages’, and identify key characteristics of the respective networks, as well as conditions and mechanisms that help the transition from stage to stage. Having established the importance of social capital and its relation with organizational outcomes, the third paper focuses on the antecedents of social capital. A longitudinal case study in the South African low-income context shows that approaches such as bricolage can be effective in enfranchising the previously disenfranchised on a broader scale.
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Stambaugh, Melony. "Seven degrees of Cincinnati social networks of social services /". Cincinnati, Ohio : University of Cincinnati, 2008. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1212181173.
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Thesis (M.A.)--University of Cincinnati, 2008.Advisor: Martha W. Rees. Title from electronic thesis title page (viewed Sep. 8, 2008). Includes abstract. Keywords: Cincinnati; social network; C. Wright Mills; H. Russell Bernard. Includes bibliographical references.
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CORO', FEDERICO. "Exploiting Social Influence to Control Opinions in Social Networks". Doctoral thesis, Gran Sasso Science Institute, 2019. http://hdl.handle.net/20.500.12571/9941.
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Social networks started as a place to comfortably connect with your friends. With them, we can communicate our thoughts and opinions over different topics and reach a large portion of users, even those who are not on your friend’s list. This has led to making social networks a crucial part of many of us, providing for example information, entertainment, and learning. Many users prefer to access social networks, like Facebook or Twitter, to have access to news as they provide faster means for information diffusion. However, as a consequence, online social networks are also exploited as a tool to alter users’ opinions, especially during political campaigns. A real-life example is the 2018 Cambridge Analytica scandal when it was revealed that the company had harvested personal data from Facebook users and used it for political advertising purposes. The idea was to target users with specific messages, which were meant to alter or reinforce user opinions. This is a concern for the health of our democracies which rely on having access to information providing diverse viewpoints. The aim of this work is to address the research issue of designing strategies to understand and overcome these processes that may have drastic consequences in our society.
We first consider the scenario in which a set of candidates are running for the elections and a social network of voters will decide the winner. Some attackers could be interested in changing the outcome of the elections by targeting a subset of voters with advertisement and/or (possibly fake) news. In this scenario we present two possible models that, exploiting influence in social networks, manipulate a voting process in order to make a target candidate win or lose the elections. We start by defining a model in which the preference list of each voter is known and give a constant factor approximation algorithm that can be used in arbitrary scoring rule voting systems, e.g., Plurality rule or Borda count. However, this assumption is not always satisfied in a realistic scenario as voters can be undecided on their preferences or they may not reveal them to the manipulator. Thus, we extend this model to design a scenario in which the manipulator can only guess a probability distribution over the candidates for each voter, instead of a deterministic preference list. Interestingly, while the problem can be approximated within a constant factor in the case of full knowledge, we show that, with partial information, the election control problem is hard to approximate within any constant factor through a reduction from Densest-k-subgraph problem, under some computational complexity hypothesis. However, we are able to show that a small relaxation of the model allows us to give a constant factor approximation algorithm.
One of the possible ways to prevent election control for the integrity of voting processes is to reduce social biases and give to the users the possibility to be exposed to multiple sources with diverse perspectives and balancing users opinions by exposing them to challenging ideas. In this perspective we first investigate the problem from a computational point of view and generalize the work introduced by Garimella et al. [1] of balancing information exposure in a social network. In this setting we obtain strong approximation hardness results, however, we mitigate these hardness results by designing an algorithm with an approximation factor of Ω (n −1/2).
Finally, we address the same issue of reducing the bias in social networks by proposing a link recommendation algorithm that evaluates the links to suggest according to their increment in social influence. We formulate the link recommendation task as an optimization problem that asks to suggest a fixed number of new connections to a subset of users with the aim of maximizing the network portion that is reached by their generated content. Thus, enhancing the possibility to spread their opinions.
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ALAWAD, NOOR ALDEEN KAMEL. "Network-aware recommendations in online social networks". Doctoral thesis, 2017. http://hdl.handle.net/11573/960039.
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Along with the rapid increase of using social networks sites such as Twitter, a massive number of tweets published every day which generally affect the users decision to forward what they receive of information, and result in making them feel overwhelmed with this information. Then, it is important for this services to help the users not lose their focus from what is close to their interests, and to find potentially interesting tweets. The problem that can occur in this case is called information overload, where an individual will encounter too much information in a short time period. For instance, in Twitter, the user can see a large number of tweets posted by her followees. To sort out this issue, recommender systems are used to give contents that match the user's needs.
This thesis presents a tweet-recommendation approach aiming at proposing novel tweets to users and achieving improvement over baseline. For this reason, we propose to exploit network, content, and retweet analyses for making recommendations of tweets.
The main objective of this research is to recommend tweets that
are unseen by the user (i.e., they do not appear in the user timeline) because nobody in her social circles published or retweeted
them. To achieve this goal, we create the user's ego-network up to depth two and apply the
transitivity property of the \emph{friends-of-friends} relationship to determine interesting recommendations. After this step, we apply cosine similarity and Jaccard distance as similarity measures for the candidate tweets obtained from the network analysis using bigrams. We also count the mutual retweets between the ego user and candidate users as a measure of shared similar tastes. The values of these features are compared together for each of the candidate tweets using pairwise comparisons in order to determine interesting recommendations that are ranked to best match the user's interests.
Experimental results demonstrate through a real user study that our approach
improves the state-of-the-art technique. In addition to the efficiency of our approach in finding relevant contents, it is also characterized by the fact of providing novel tweets, which solves the over-specialization challenge or serendipity problem that appears when using content-based recommender systems as a stand alone approach of recommendation.
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Sperlì, Giancarlo. "MULTIMEDIA SOCIAL NETWORKS". Tesi di dottorato, 2017. http://www.fedoa.unina.it/12167/1/Tesi_Giancarlo_Sperli.pdf.
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Nowadays, On-Line Social Networks represent an interactive platform to share -- and very often interact with -- heterogeneous content for different purposes (e.g to comment events and facts, express and share personal opinions on specific topics, and so on), allowing millions of individuals to create on-line profiles and communicate personal information.
In this dissertation, we define a novel data model for Multimedia Social Networks (MSNs), i.e. social networks that combine information on users -- belonging to one or more social communities -- with the multimedia content that is generated and used within the related environments. The proposed data model, inspired by hypergraph-based approaches, allows to represent in a simple way all the different kinds of relationships that are typical of these environments (among multimedia contents, among users and multimedia content and among users themselves) and to enable several kinds of analytics and applications.
Exploiting the feature of MSN model, the following two main challenging problems have been addressed: the Influence Maximization and the Community Detection. Regarding the first problem, a novel influence diffusion model has been proposed that, learning recurrent user behaviors from past logs, estimates the probability that a given user can influence the other ones, basically exploiting user to content actions. On the top of this model, several algorithms (based on game theory, epidemiological etc.) have been developed to address the Influence Maximization problem. Concerning the second challenge, we propose an algorithm that leverages both user interactions and multimedia content in terms of high and low-level features for identifying communities in heterogeneous network.
Finally, experimental analysis have been made on a real Multimedia Social Network ("Flickr") for evaluating both the feasibility of the model and the effectiveness of the proposed approaches for Influence Maximization and community detection.
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Ming-ChaoWang i 王明照. "Beyond social networks: Constructing the knowledge networks". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/48751409795860111509.
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博士國立成功大學
企業管理學系碩博士班
99
Scholars in network research have primarily emphasized the tie strength and structural characteristics of what has been called “the social network,” rather than the content and mechanism of network formation. Typically, researchers see social networks as accruing from the particular interactions organizations have for channeling and exchanging knowledge. In this research we seek to contribute to the body of work on networks by discussing the following: (1) the structural characteristics of networks and the content of inter-organizational interactions; (2) the way the three dimensions of knowledge networks facilitate organizations to accumulate and create knowledge; and (3) the ability of an organization to develop and manage the knowledge network in a competitive environment. We present a model that integrates the arguments made in this paper through a series of hypothesized relationships between different dimensions of knowledge networks and the main mechanisms for innovative outcomes. The research for this study is based on 164 high-technology firms from Taiwan science parks, and 80 additional firms that were generated using the snowball method rounded five times. Thus, 344 firms were investigated in the knowledge network. In order to fit the real environment and ensure the validity of questionnaire items, ten top management team members from high-technology firms were asked to verify the clarity of the measurements. After collecting complete financing data and the company portfolio of participating firms, we mailed a three-wave questionnaire and followed up on the mailings with phone calls. Finally, we received 144 questionnaires back, yielding a 41.86% response rate. The results of this research provide strong support for all hypotheses. Network structure and knowledge heterogeneity have a positive impact on knowledge cognition. Moreover, knowledge cognition has a positive influence on innovative performance. The findings indicate that knowledge cognition plays a critical role in the knowledge network by storing knowledge capacities that increase innovative outcomes. Managerial implications for inter-organizational network configuration and content, knowledge heterogeneity and quality, and strategy and decision making are also discussed.
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Ye, Mengbin. "Opinion Dynamics and the Evolution of Social Power in Social Networks". Phd thesis, 2018. http://hdl.handle.net/1885/146402.
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A fundamental aspect of society is the exchange and discussion of
opinions between individuals, occurring in mediums and situations
as varied as company boardrooms, elementary school classrooms and
online social media. This thesis studies several mathematical
models of how an individual’s opinion(s) evolves via
interaction with others in a social network, developed to reflect
and capture different socio-psychological processes that occur
during the interactions.
In the first part, and inspired by Solomon E. Asch’s seminal
experiments on conformity, a novel discrete-time model of opinion
dynamics is proposed, with each individual having both an
expressed and a private opinion on the same topic. Crucially, an
individual’s expressed opinion is altered from the
individual’s private opinion due to pressures to conform to the
majority opinion of the social network. Exponential convergence
of the opinion dynamical system to a unique configuration is
established for general networks. Several conclusions are
established, including how differences between an individual’s
expressed and private opinions arise, and how to estimate
disagreement among the private opinions at equilibrium. Asch’s
experiments are revisited and re-examined, and then it is shown
that a few extremists can create “pluralistic ignorance”,
where people believe there is majority support for a position but
in fact the position is privately rejected by the majority of
individuals!
The second part builds on the recently proposed discrete-time
DeGroot–Friedkin model, which describes the evolution of an
individual’s self-confidence (termed social power) in his/her
opinion over the discussion of a sequence of issues. Using
nonlinear contraction analysis, exponential convergence to a
unique equilibrium is established for networks with constant
topology. Networks with issue-varying topology (which remain
constant for any given issue) are then studied; exponential
convergence to a unique limiting trajectory is established. In a
social context, this means that each individual forgets his/her
initial social power exponentially fast; in the limit, his/her
social power for a given issue depends only on the previously
occurring sequence of dynamic topology. Two further related works
are considered; a network modification problem, and a different
convergence proof based on Lefschetz Fixed Point Theory.
In the final part, a continuous-time model is proposed to capture
simultaneous discussion of logically interdependent topics; the
interdependence is captured by a “logic matrix”. When no
individual remains attached to his/her initial opinion, a
necessary and sufficient condition for the network to reach a
consensus of opinions is provided. This condition depends on the
interplay between the network interactions and the logic matrix;
if the network interactions are too strong when compared to the
logical couplings, instability can result. Last, when some
individuals remain attached to their initial opinions, sufficient
conditions are given for opinions to converge to a state of
persistent disagreement.
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Freitas, Joana Azevedo de. "Elderly social support networks". Master's thesis, 2013. http://hdl.handle.net/10071/7203.
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Demographic trends have been evidencing an aged reality. Ageing is a phenomenon noticed in every human body systems and, gradually in his mind. The comparison between European countries aims to stress the main differences and similarities according to Welfare State regimes. The consequent Social Policies for the aged influence the elderly lifestyle and, eventually, the type of social support and social support networks around the eldest family members.As tendências demográficas têm evidenciado uma realidade envelhecida. O fenómeno do envelhecimento é sentido em todos os sistemas do corpo humano e, gradualmente, na sua mente. A comparação entre países Europeus visa destacar as principais diferenças e semelhanças, de acordo com o Regime de Estado Providência. As consequentes Políticas Sociais de Idosos influenciam o estilo de vida dos mesmos e, por último, o tipo de suporte social e redes sociais de suporte desenvolvidas em torno dos membros mais velhos da família.
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Cordeiro, João Miguel Magalhães Marcelino Fernandes. "Sound based social networks". Doctoral thesis, 2013. http://hdl.handle.net/10400.14/15773.
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The sound environment is an eco of the activity and character of each
place, often carrying additional information to that made available to the eyes
(both new and redundant). It is, therefore, an intangible and volatile acoustic
fingerprint of the place, or simply an acoustic snapshot of a single event. Such
rich resource, full of meaning and subtleness, Schaeffer called Soundscape.
The exploratory research project presented here addresses the Soundscape
in the context of Mobile Online Social Networking, aiming at determining the
extent of its applicability regarding the establishment and/or strengthening of
new and existing social links. Such research goal demanded an interdisciplinary
approach, which we have anchored in three main stems: Soundscapes,
Mobile Sound and Social Networking. These three areas pave the scientific
ground for this study and are introduced during the first part of the thesis. An
extensive survey of the state-of-the-arte projects related with this research is
also presented, gathering examples from different but adjacent areas such as
mobile sensing, wearable computing, sonification, social media and contextaware
computing. This survey validates that our approach is scientifically opportune
and unique, at the same time.
Furthermore, in order to assess the role of Soundscapes in the context
of Social Networking, an experimental procedure has been implemented
based on an Online Social Networking mobile application, enriched with environmental
sensing mechanisms, able to capture and analyze the surrounding
Soundscape and users' movements. Two main goals guided this prototypal
research tool: collecting data regarding users' activity (both sonic and kinetic)
and providing users with a real experience using a Sound-Based Social Network,
in order to collect informed opinions about this unique type of Social
Networking. The application – Hurly-Burly – senses the surrounding Soundscape
and analyzes it using machine audition techniques, classifying it according
to four categories: speech, music, environmental sounds and silence. Additionally, it determines the sound pressure level of the sensed Soundscape
in dB(A)eq. This information is then broadcasted to the entire online social
network of the user, allowing each element to visualize and audition a representation
of the collected data. An individual record for each user is kept
available in a webserver and can be accessed through an online application,
displaying the continuous acoustic profile of each user along a timeline graph.
The experimental procedure included three different test groups, forming each
one a social network with a cluster coefficient equal to one.
After the implementation and result analysis stages we concluded that
Soundscapes can have a role in the Online Social Networking paradigm, specially
when concerning mobile applications. Has been proven that current offthe-
shelf mobile technology is a promising opportunity for accomplishing this
kind of tasks (such as continuous monitoring, life logging and environment
sensing) but battery limitations and multitasking's constraints are still the bottleneck,
hindering the massification of successful applications. Additionally,
online privacy is something that users are not enthusiastic in letting go: using
captured sound instead of representations of the sound would abstain users
from utilizing such applications. We also demonstrated that users who are
more aware of the Soundscape concept are also more inclined to assume it
as playing an important role in OSN. This means that more pedagogy towards
the acoustic phenomenon is needed and this type of research gives a step
further in that direction.O ambiente sonoro de um lugar é um eco da sua atividade e carácter, transportando, na maior parte da vezes, informação adicional àquela que é proporcionada à visão (quer seja redundante ou complementar). É, portanto, uma impressão digital acústica - tangível e volátil - do lugar a que pertence, ou simplesmente uma fotografia acústica de um evento pontual. A este opulento recurso, carregado de significados e subtilezas, Schafer chamou de Paisagem-Sonora. O projeto de investigação de carácter exploratório que aqui apresentamos visa o estudo da Paisagem-Sonora no contexto das Redes Sociais Móveis Em-Linha, procurando entender os moldes e limites da sua aplicação, tendo em vista o estabelecimento e/ou reforço de novos ou existente laços sociais, respectivamente. Para satisfazer este objectivo foi necessária uma abordagem multidisciplinar, ancorada em três pilares principais: a Paisagem-Sonora, o Som Móvel e as Redes Sociais. Estas três áreas determinaram a moldura científica de referência em que se enquadrou esta investigação, sendo explanadas na primeira parte da tese. Um extenso levantamento do estado-da-arte referente a projetos relacionados com este estudo é também apresentado, compilando exemplos de áreas distintas mas adjacentes, tais como: Computação Sensorial Móvel, Computação Vestível, Sonificação, Média Social e Computação Contexto-Dependente. Este levantamento veio confirmar quer a originalidade quer a pertinência científica do projeto apresentado. Posteriormente, a fim de avaliar o papel da Paisagem-Sonora no contexto das Redes Sociais, foi posto em prática um procedimento experimental baseado numa Rede Social Sonora Em-Linha, desenvolvida de raiz para dispositivos móveis e acrescida de mecanismos sensoriais para estímulos ambientais, capazes de analisar a Paisagem-Sonora envolvente e os movimentos do utilizador. Dois objectivos principais guiaram a produção desta ferramenta de investigação: recolher dados relativos à atividade cinética e sonora dos utilizadores e proporcionar a estes uma experiência real de utilização uma Rede Social Sonora, de modo a recolher opiniões fundamentadas sobre esta tipologia específica de socialização. A aplicação – Hurly-Burly – analisa a Paisagem-Sonora através de algoritmos de Audição Computacional, classificando- a de acordo com quatro categorias: diálogo (voz), música, sons ambientais (“ruídos”) e silêncio. Adicionalmente, determina o seu nível de pressão sonora em dB(A)eq. Esta informação é então distribuída pela rede social dos utilizadores, permitindo a cada elemento visualizar e ouvir uma representação do som analisado. É mantido num servidor Web um registo individual da informação sonora e cinética captada, o qual pode ser acedido através de uma aplicação Web que mostra o perfil sonoro de cada utilizador ao longo do tempo, numa visualização ao estilo linha-temporal. O procedimento experimental incluiu três grupos de teste distintos, formando cada um a sua própria rede social com coeficiente de aglomeração igual a um. Após a implementação da experiência e análise de resultados, concluímos que a Paisagem- Sonora pode desempenhar um papel no paradigma das Redes Sociais Em- Linha, em particular no que diz respeito à sua presença nos dispositivos móveis. Ficou provado que os dispositivos móveis comerciais da atualidade apresentam-se com uma oportunidade promissora para desempenhar este tipo de tarefas (tais como: monitorização contínua, registo quotidiano e análise sensorial ambiental), mas as limitações relacionadas com a autonomia energética e funcionamento em multitarefa representam ainda um constrangimento que impede a sua massificação. Além disso, a privacidade no mundo virtual é algo que os utilizadores atuais não estão dispostos a abdicar: partilhar continuamente a Paisagem-Sonora real em detrimento de uma representação de alto nível é algo que refrearia os utilizadores de usar a aplicação. Também demonstrámos que os utilizadores que mais conhecedores do fenómeno da Paisagem-Sonora são também os que consideram esta como importante no contexto das Redes Sociais Em-Linha. Isso significa que uma atitude pedagógica em relação ao fenómeno sonoro é essencial para obter dele o maior ganho possível. Esta investigação propõe-se a dar um passo em frente nessa direção.
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Gonçalves, Ricardo Jorge Girante. "Cybersecurity in social networks". Master's thesis, 2022. http://hdl.handle.net/10362/133016.
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Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Knowledge Management and Business IntelligenceIn recent years, the use of social networks has been increasing substantially. As we know, platforms such as Facebook, Twitter, Google +, Pinterest, LinkedIn or Instagram allow millions of individuals to create online profiles and share personal information with several friends through social networks – and, often, it’s possible to do the same with a large amount of strangers. By itself, social networks should not be considered a cyber threat. However, there are several issues related to maintaining the user’s data security and privacy, especially when they upload personal information, photos and / or videos. The large majority of users ignores the security best practices, which sometimes facilitates the hackers’ attacks. The main goal of this research is to understand patterns of information that are revealed on online social networks and their privacy implications. The goal is to map people behaviour on social networks and understand if they care about the security of their data exposed on the Internet. This research also aims to understand the impact of cybersecurity in social networks and a comparison of which social network is most concerned with the exposure of its user. It will be also addressed the current defence solutions that can protect social network users from these kinds of threats.
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Waniek, Marcin. "Hiding in Social Networks". Doctoral thesis, 2017. https://depotuw.ceon.pl/handle/item/2174.
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The Internet and social media have fuelled enormous interest in social network analysis. New tools continue to be developed and used to analyse our personal connections. This raises privacy concerns that are likely to exacerbate in the future. With this in mind, we ask the question: Can individuals or groups actively manage their connections to evade social network analysis tools? By addressing this question, the general public may better protect their privacy, oppressed activist groups may better conceal their existence, and security agencies may better understand how terrorists escape detection.In this dissertation we consider hiding from three different types of social network analysis tools. First, we study how both an individual and a group of nodes can evade analysis utilizing centrality measures, without compromising ability to participate in network's activities. In the second study, we investigate how a community can avoid being identified by a community detection algorithm as a closely cooperating group of nodes. In the third study, we analyse how a presence of a particular edge in a network can be hidden from link prediction algorithms.For considered problems we analyse their computational complexity and prove that they are usually NP-hard.However, we also provide polynomial-time heuristic solutions that turn out to be effective in practice. We test our algorithms on a number of real-life and artificially generated network datasets.Internet 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.