On the k-anonymization of time-varying and multi-layer social graphs

The popularity of online social media platforms provides an unprecedented opportunity to study real-world complex networks of interactions. However, releasing this data to researchers and the public comes at the cost of potentially exposing private and sensitive user information. It has been shown that a naive anonymization of a network by removing the identity of the nodes is not sufficient to preserve users’ privacy. In order to deal with malicious attacks, k -anonymity solutions have been proposed to partially obfuscate topological information that can be used to infer nodes’ identity. In this paper, we study the problem of ensuring k anonymity in time-varying graphs, i.e., graphs with a structure that changes over time, and multi-layer graphs, i.e., graphs with multiple types of links. More specifically, we examine the case in which the attacker has access to the degree of the nodes. The goal is to generate a new graph where, given the degree of a node in each (temporal) layer of the graph, such a node remains indistinguishable from other k-1 nodes in the graph. In order to achieve this, we find the optimal partitioning of the graph nodes such that the cost of anonymizing the degree information within each group is minimum. We show that this reduces to a special case of a Generalized Assignment Problem, and we propose a simple yet effective algorithm to solve it. Finally, we introduce an iterated linear programming approach to enforce the realizability of the anonymized degree sequences. The efficacy of the method is assessed through an extensive set of experiments on synthetic and real-world graphs.

Exploring demographic information in social media for product recommendation

In many e-commerce Web sites, product recommendation is essential to improve user experience and boost sales. Most existing product recommender systems rely on historical transaction records or Web-site-browsing history of consumers in order to accurately predict online users’ preferences for product recommendation. As such, they are constrained by limited information available on specific e-commerce Web sites. With the prolific use of social media platforms, it now becomes possible to extract product demographics from online product reviews and social networks built from microblogs. Moreover, users’ public profiles available on social media often reveal their demographic attributes such as age, gender, and education. In this paper, we propose to leverage the demographic information of both products and users extracted from social media for product recommendation. In specific, we frame recommendation as a learning to rank problem which takes as input the features derived from both product and user demographics. An ensemble method based on the gradient-boosting regression trees is extended to make it suitable for our recommendation task. We have conducted extensive experiments to obtain both quantitative and qualitative evaluation results. Moreover, we have also conducted a user study to gauge the performance of our proposed recommender system in a real-world deployment. All the results show that our system is more effective in generating recommendation results better matching users’ preferences than the competitive baselines.

ToPI - uma abordagem online para identificar locais de interesse utilizando fotografias geo-referenciadas

Due to the growing use of social networks people no longer just consume data, they also produce and share it. Geo-tagged information, i.e., data with geographical location, have been used in many attempts to identify popular places and help tourists that will visit unfamiliar cities. This Master Thesis presents an online strategy that uses geo-tagged photos and their metadata in order to identify places of interest inside a given geographical area and retrieve relevant related information. The whole process runs automatically in real time, returning updated information about places. The proposed strategy takes into account the inherent dynamism of social media, and thus is robust under inconsistencies and/or outdated information, a common issue in solutions that rely on previously stored data. The analysis of the results showed that our approach is very promising, returning places that present high agreement with those from a popular travel website.

Please Stop Rubbing Your Relationship In My Face(book): An Investigation of Online Romantic Social Comparison

It is well-documented that social networking sites such as Facebook set the stage for social comparison. Such comparison has been linked to a number of negative outcomes including envy, negative moods, and lower self-esteem. The present research aims to extend current understanding of online social comparison by investigating how it pertains to romantic relationships. I hypothesized that for individuals high in attachment anxiety (compared to those low in this construct), online romantic social comparison might be related to negative consequences—which, in the current project, was operationalized as lower mood/affect and state self-esteem. Further, I hypothesized that there would be an interaction between attachment anxiety and relationship insecurities on these negative outcomes, such that the expected difference of attachment anxiety would be more pronounced under conditions priming relationship insecurities, relative to a control condition. Two experiments were conducted, one of which focused on single individuals, and the second focusing on individuals who were themselves in dating relationships. The paradigms of each entailed experimental manipulation of a key relationship-related variable (for single individuals, pessimism for future relationships; for dating individuals, the presence or absence of rejection threat), subsequent exposure to romantic content from Facebook, and finally, measures of affect and state self-esteem. I discovered partial support for the hypothesis that some single individuals—particularly those with higher, rather than lower, attachment anxiety—do indeed report feeling more negative moods and lower state self-esteem following exposure to romantic online content, in contrast to single individuals who had instead viewed neutral online content. The association between attachment anxiety and negative outcome was especially pertinent if individuals had been primed to believe that their own future romantic prospects were grim, or if attention had been drawn to their singleness. Among dating individuals, less support for hypotheses was found; however, exploratory post-hoc analyses revealed a promising (albeit weak) trend indicating that reinvestigation of the current hypotheses would be prudent.

El impacto de la presencia online en las cuentas de Twitter de las universidades vascas y navarras

Las Universidades han tenido que adaptarse a los nuevos modelos de comunicación surgidos en la época de Internet. Dentro de estos nuevos paradigmas las redes sociales han irrumpido y Twitter se ha establecido como una de las más importantes. El objetivo de esta investigación es demostrar que existe una relación entre la presencia online de una Universidad, definida por la cantidad de información disponible en Internet, y su cuenta en Twitter. Para ello se analizó la relación entre la presencia online y los perfiles oficiales de las cinco universidades del País Vasco y Navarra. Los resultados demostraron la existencia de una correlación significativa entre la presencia online de las instituciones y el número de seguidores de sus respectivas cuentas. En segundo lugar, esta investigación se planteó si Twitter puede servir para potenciar la presencia online de una Universidad. Es por eso que se formuló una segunda hipótesis que buscaba analizar si tener varias cuentas en Twitter aumentaría la presencia online de las Universidades. Los hallazgos para esta segunda hipótesis demostraron una correlación muy significativa entre tener varios perfiles en Twitter y la presencia online de las Universidades. Así queda demostrada la importancia de la presencia online para las cuentas de Twitter y la relevancia de Twitter a la hora de potenciar la presencia online de los centros.

The activity of the feminist online publications: challenges for the transmission of the feminist culture in Spain

Traditionally, big media corporations have contributed to hiding the women’s movement itself, as well as its main claims and topics of discussion (Marx, Myra y Hess, 1995; Rhode, 1995; Mendes, 2011). This has led the feminist movement to develop its own media generally print publications, usually, with a very specialized character and reduced audience. This is similar to what has occurred with quality main stream media, asthese publications have had to adapt themselves to a new communicatiion context, because of the financial crisis and  technological evolution. Feminist media has found in the Internet an excellent opportunity to access citizens and communicate their messages. , In view of this scene of change and renovation,  this article offers the results of a qualitative analysis focused on the experiences of four feminist online media sites edited in Spain: Pikaramagazine.com, Proyecto-kahlo.com, Mujeresenred.net and Laindependent.cat. Besides exploring the characteristics and content of these sites, the article pays attention to the virality of their contents spread through Facebook and Twitter. The onclusion estimates their social impact, insofar as they symbolize the specialization, diversification and dialogue promoted by the Web.

Intervenção social com crianças refugiadas: estratégias profissionais do Serviço Social com crianças refugiadas em Portugal

O objetivo principal é analisar a Intervenção social com crianças refugiadas em Portugal e as estratégias profissionais do Serviço Social como resposta às necessidades dessas crianças. Assim, pretendemos conhecer de que forma o assistente social, enquanto agente ativo na sociedade e capacitado de uma ação meditativa, produz respostas a esta problemática e conhecer também a realidade do nosso país relativamente à chegada de crianças refugiadas. A metodologia de investigação usada foi qualitativa tendo sido, realizado um questionário com oito perguntas fechadas e abertas, sendo divulgado on-line pelas redes sociais em grupos de serviço social. Foram recolhidas oito respostas, no entanto dois inquéritos não se enquadravam nos critérios de inclusão definidos pelo que foram excluídos. A partir dos dados obtidos foi possível perceber que existe uma estrutura preparada em Portugal para proceder ao acolhimento de crianças refugiadas sozinhas, que considera nos seus procedimentos o superior interesse da criança mas que padece ainda de algumas lacunas, nomeadamente ao nível da formação dos agentes de intervenção no terreno e do ensino da língua portuguesa. / The present study aimed to analyze the social intervention with refugee children in Portugal and the professional strategies of social workers in order to insure the needs of these children. Our main objective was to understand how the social worker, as an active agent in society and capable of a meditative action, produces answers to this problem and also know the reality of our country in respect to the arrival of refugee children. By the use of qualitative research methodology and the application of a questionnaire, composed with eight open and closed questions, published online in social networks of social service groups, we came up with eight responses. However two surveys did not fit the inclusion criteria defined and, therefore, were excluded. From the data obtained it was revealed that there is a structure prepared in Portugal to carry out the reception of refugee unattended children. It is a structure that considers the procedures regarding the best interests of the child, but it still suffers from some shortcomings, particularly in terms of training of intervention agents on the ground and in the tutorship of Portuguese language.

Suporte, Stress e Solidão: um estudo sobre o apoio offline e online percecionado pelas mães portuguesas

Uma “rede social” diz respeito a uma estrutura constituída por pessoas ou organizações que partilham interesses, motivações e valores comuns. Um ponto partilhado pelos diversos tipos de rede social é a troca de informações, conhecimentos, interesses e esforços na tentativa de atingir objectivos comuns, muitas vezes potencializando forças e recursos em situações de crise. Recentemente tem-se ouvido falar bastante deste conceito aplicado à internet. A maternidade constitui, por si só, um momento de crise na vida de cada família e de cada mulher, requerendo adaptações e mudanças. O estudo realizado teve o intuito de avaliar o suporte online e offline (denominando-se essas ligações de redes sociais), no caso específico de assuntos ligados à maternidade. Pretendeu-se verificar também se existia uma correlação entre estes tipos de suporte e os níveis de stress e solidão sentidos pelas mães. Por último, aferiu-se ainda a influência que a idade dos filhos teria nesta adesão a grupos de suporte à maternidade, no Facebook. Este estudo teve uma amostra constituída por 170 mulheres (mães), estando as suas idades compreendidas entre os 25 e os 62 anos. Os resultados revelaram que apesar de não haver diferenças estatisticamente significativas entre o apoio online e offline, as mulheres que pertencem a grupos do Facebook tendem a sentir mais suporte por parte das plataformas de suporte disponíveis. Constatou-se ainda que não existem diferenças significativas entre os níveis de solidão e stress, entre mães que pertencem a grupos e mães que não pertencem. Foi interessante verificar que as mulheres com filhos mais novos (faixa etária dos 0-4 anos) têm uma presença mais significativa em grupos de apoio à maternidade, no Facebook. Pensamos que isso se deve às dúvidas e ao stresse gerado por um primeiro filho ou pela introdução de mais um filho no núcleo familiar, nos primeiros anos em que tal ocorre, procurando por isso mais activamente grupos que ajudem como rede de suporte, para partilhas, apoio emocional e esclarecimento de dúvidas. / A “social network” refers to a structure formed by individuals or organisations that share interests, motivations and common values. A feature shared by several types of social network is the exchange of information, knowledge, interests and efforts, in an attempt to achieve common goals, often potentiating strengths and resources in crisis situations. Recently, we have heard of this concept applied to the internet. Motherhood is, by itself, a moment of crisis in the life of every family and every woman, requiring adaptations and changes. This study aimed to assess online and offline supports (being these connections themselves denominated social networks), in the specific case of motherhood-related issues. It was also intended to confirm whether there was a correlation between these types of support and stress and loneliness levels sensed by mothers. Finally, it was evaluated as well the influence that the children’s age would have on this adherence to motherhood support groups on Facebook. This study had a sample of 170 women (mothers), with ages between 25 and 62 years. The results showed that, although there are no statistically significant differences between the online and offline support, women who belong to Facebook groups tend to feel more support from the available support platforms. It was shown as well that there are no significant differences between loneliness and stress levels among mothers who belong to groups and mothers who do not belong to those groups. It was interesting to find that women with young children (aged 0-4 years old) have a more significant presence in motherhood support groups on Facebook. We think that this is due to the doubts and the stress generated by a first child or the introduction of another child in the household, therefore making sense that they seek, in the early years of the child’s life, groups that help as a support network, for shares, emotional support and answering questions.

The role of networking and social media tools during job search: an information behaviour perspective.

The paper presents a critical analysis of the extant literature pertaining to the networking behaviours of young jobseekers in both offline and online environments. A framework derived from information behaviour theory is proposed as a basis for conducting further research in this area. Method. Relevant material for the review was sourced from key research domains such as library and information science, job search research, and organisational research. Analysis. Three key research themes emerged from the analysis of the literature: (1) social networks, and the use of informal channels of information during job search, (2) the role of networking behaviours in job search, and (3) the adoption of social media tools. Tom Wilson’s general model of information behaviour was also identified as a suitable framework to conduct further research. Results. Social networks have a crucial informational utility during the job search process. However, the processes whereby young jobseekers engage in networking behaviours, both offline and online, remain largely unexplored. Conclusion. Identification and analysis of the key research themes reveal opportunities to acquire further knowledge regarding the networking behaviours of young jobseekers. Wilson’s model can be used as a framework to provide a holistic understanding of the networking process, from an information behaviour perspective.

Joint Optimization for Social Content Delivery in Wireless Networks

Over the last decade, success of social networks has significantly reshaped how people consume information. Recommendation of contents based on user profiles is well-received. However, as users become dominantly mobile, little is done to consider the impacts of the wireless environment, especially the capacity constraints and changing channel. In this dissertation, we investigate a centralized wireless content delivery system, aiming to optimize overall user experience given the capacity constraints of the wireless networks, by deciding what contents to deliver, when and how. We propose a scheduling framework that incorporates content-based reward and deliverability. Our approach utilizes the broadcast nature of wireless communication and social nature of content, by multicasting and precaching. Results indicate this novel joint optimization approach outperforms existing layered systems that separate recommendation and delivery, especially when the wireless network is operating at maximum capacity. Utilizing limited number of transmission modes, we significantly reduce the complexity of the optimization. We also introduce the design of a hybrid system to handle transmissions for both system recommended contents ('push') and active user requests ('pull'). Further, we extend the joint optimization framework to the wireless infrastructure with multiple base stations. The problem becomes much harder in that there are many more system configurations, including but not limited to power allocation and how resources are shared among the base stations ('out-of-band' in which base stations transmit with dedicated spectrum resources, thus no interference; and 'in-band' in which they share the spectrum and need to mitigate interference). We propose a scalable two-phase scheduling framework: 1) each base station obtains delivery decisions and resource allocation individually; 2) the system consolidates the decisions and allocations, reducing redundant transmissions. Additionally, if the social network applications could provide the predictions of how the social contents disseminate, the wireless networks could schedule the transmissions accordingly and significantly improve the dissemination performance by reducing the delivery delay. We propose a novel method utilizing: 1) hybrid systems to handle active disseminating requests; and 2) predictions of dissemination dynamics from the social network applications. This method could mitigate the performance degradation for content dissemination due to wireless delivery delay. Results indicate that our proposed system design is both efficient and easy to implement.

‘I can use things, but I can't make anything’: a qualitative exploration of team networks in the development and implementation of a new undergraduate e-compendium

In higher education, undergraduate teaching materials are increasingly becoming available online. There is a need to understand the complex processes that happen during their production and how social networks between different groups impact on their development. This paper draws on qualitative interviews and participant drawings of their social networks to understand the dynamics of creating a new e-compendium for a four-year online undergraduate nursing programme in Norway. Twenty staff interviews were undertaken to explore views of the e-compendium, the development process and the perceived networks that were formed during this course. Interview data were thematically analysed along with networks drawings. The findings showed three main institutional stakeholder groups emerging: the ‘management team’, ‘design team’ and ‘lecturers’. Analysis of social networks revealed variability of relations both within and between groups. The pedagogical designer, who was part of the design team, was central to communicating with and co-ordinating staff at all levels. The least well connected were the lecturers. To them, the e-compendium challenged and even threatened previously well-established notions of pedagogy. Future development of e-compendiums should account for the perceived lack of time and existing workload of lecturers so they may be involved with the development process.

Who supports? The providers of social support to dual-parent families caring for young children

Previous research points to the importance of both kin and non-kin ties within social networks as sources of social support. This study examines the kin and non-kin providers of specific types of support to dual-parent low-income Australian families caring for young children. The study highlights the importance of family and friends as support providers. Study Participants tended to rely on family, including parents, siblings and other family members, and friends for emotional and information support. Parents also tended to provide material and practical support. While neighbors and community agencies offered some emotional and information support, overall, these sources were minimal. (C) 2002 Wiley Periodicals, Inc.

The perceived potential of business social networking sites

Business social networking is a facilitator of several business activities, such as market studies, communication with clients, and identification of business partners. This paper traduces the results of a study undertaken with the purpose of getting to know how the potential of networking is perceived in the promotion of business by participants of the LinkedIn network, and presents two main contributions: (1) to disseminate within the business community which is the relevance given to social networking; and (2) which are the social networks best suitable to the promotion of business, to support the definition of strategies and approaches accordingly. The results confirm that LinkedIn is the most suitable network to answer the needs of those that look for professional contacts and for the promotion of business, while innovation is the most recognized factor in the promotion of business through social networking. This study contributes to a better understanding of the potential of different business social networking sites, to support organizations and professionals to align their strategies with the perceived potential of each network.

A blockmodel study of managerial hierarchies, verbal networks, and organizational culture in four hospitals

This study demonstrates and applies a social network methodology for studying the dynamics of hierarchies in organizations. Social network (blockmodel) analysis of verbal networks in four hospitals contrasted hierarchical and structurally equivalent partitions of the sociomatrices of frequent ties and perceptions of organizational culture. It was found that the verbal networks in these organizations follow a center periphery pattern rather than a hierarchical logic and that perceptions of culture vary more by verbal network than by formal hierarchy. The perceptions of culture of central groups in one organization are much like those of peripheral groups in another. In all four hospitals, structurally equivalent social networks are more important in predicting subcultures than are hierarchical groupings and hierarchy has a limited impact on the development of verbal networks. These findings suggest the value of an amoeba rather than a pyramid metaphor in interpreting the cultures and relational structures of organizations.

A influência do eWOM gerado pelos grupos de referência no Facebook, em Portugal

Dissertação apresentada ao Instituto Superior de Contabilidade e Administração do Porto para a obtenção do Grau de Mestre em Marketing Digital. Orientado por Mestre Inês Veiga Pereira