Friends for Free: Self-Organizing Artificial Social Networks for Trust and Cooperation

By harvesting friendship networks from e-mail contacts or instant message "buddy lists" Peer-to-Peer (P2P) applications can improve performance in low trust environments such as the Internet. However, natural social networks are not always suitable, reliable or available. We propose an algorithm (SLACER) that allows peer nodes to create and manage their own friendship networks. We evaluate performance using a canonical test application, requiring cooperation between peers for socially optimal outcomes. The Artificial Social Networks (ASN) produced are connected, cooperative and robust - possessing many of the disable properties of human friendship networks such as trust between friends (directly linked peers) and short paths linking everyone via a chain of friends. In addition to new application possibilities, SLACER could supply ASN to P2P applications that currently depend on human social networks thus transforming them into fully autonomous, self-managing systems

What Users Want (WUW): un servicio de satisfacción de usuarios orientado a aplicaciones de distribución de contenidos

En este trabajo, se presenta el servicio WUW que permite a los usuarios expresar sus preferencias y que sean tomadas en cuenta durante el proceso de distribución. Se presenta su arquitectura e implementación. De igual forma, WUW permite medir la satisfacción de los usuarios y cómo la aplicación P2P utilizada considera las preferencias de los usuarios, proporcionando una retroalimentación inspirada en Satisfaction-Based Query Load Balancing framework (SQLB) [5], pero cuya definición formal en WUW es esencialmente diferente [6] [7]. También como parte de nuestro trabajo de investigaci´on se diseña una interfaz web, que actúa como un intermediario entre los usuarios y el servicio WUW, a través de la cual los usuarios definen sus preferencias para que WUW pueda considerarlas, y le muestra a los usuarios la retroalimentación proporcionada por WUW. Finalmente, se realiza la evaluación del servicio WUW utilizando como aplicación P2P BitTorrent, el cual utiliza uno de los protocolos más popular para el intercambio de contenidos. Los resultados de nuestra evaluación, muestran que la presencia del servicio WUW no afecta el rendimiento de BitTorrent al considerar las preferencias de los usuarios al momento de seleccionar con quienes se desea compartir el contenido. Así mismo, se presenta una demostración del uso de la interfaz web, que permite a los usuarios definir sus preferencias.Las aplicaciones Par-a-Par (P2P) se han vuelto populares debido a su alta escalabilidad, y es gracias a la participación de los usuarios que el proceso de distribución se lleva a cabo, ya que estos comparten sus recursos (como el ancho de banda, almacenamiento, etc.) e intercambian el contenido con otros usuarios. Es por ello que hoy en día, muchas aplicaciones P2P pertenecen a la categoría de distribución de contenidos, las cuales van desde el intercambio de archivos hasta los sistemas que permiten crear una infraestructura P2P para organizar, buscar, y recuperar contenido [1]. No obstante, a pesar de su éxito, aún existen diferentes problemáticas relacionadas con el procesos de distribución. La mayoría de los trabajos relacionados con este tema enfocan sus esfuerzos en mejorar la arquitectura, la robustez en escenarios de alta dinamicidad o bien de mejorar la habilidad de descubrir nuevos pares para compartir contenido. En otras palabras, el enfoque en estas propuestas se basa principalmente en la calidad de servicio ofrecida [2][3][4]. Debido a que gracias a los usuarios, la distribución de contenidos se lleva a cabo, este tipo de aplicaciones no sólo deben preocuparse por la calidad de servicio, sino también por la satisfacción de sus usuarios, ya que son los principales actores en estas aplicaciones. Por lo tanto, este tipo de aplicaciones deberían hacer que los usuarios participen más en el proceso de distribución, teniendo en cuenta sus preferencias sobre el contenido y la información que comparten. Sin embargo, ninguna de las aplicaciones P2P de distribución de contenidos estudiadas en el presente trabajo considera las preferencias de los usuarios. Por lo que, se propone la utilización de un servicio que permita a los usuarios definir sus preferencias y tomarlas en consideración para la selección de los usuarios con los que desea intercambiar el contenido

Cues disseminated by professional associations that represent 5 health care professions across 5 nations : lexical analysis of tweets

Background: Collaboration across health care professions is critical in efficiently and effectively managing complex and chronic health conditions, yet interprofessional care does not happen automatically. Professional associations have a key role in setting a profession’s agenda, maintaining professional identity, and establishing priorities. The associations’ external communication is commonly undertaken through social media platforms, such as Twitter. Despite the valuable insights potentially available into professional associations through such communication, to date, their messaging has not been examined. Objective: This study aimed to identify the cues disseminated by professional associations that represent 5 health care professions spanning 5 nations. Methods: Using a back-iterative application programming interface methodology, public tweets were sourced from professional associations that represent 5 health care professions that have key roles in community-based health care: general practice, nursing, pharmacy, physiotherapy, and social work. Furthermore, the professional associations spanned Australia, Canada, New Zealand, the United Kingdom, and the United States. A lexical analysis was conducted of the tweets using Leximancer (Leximancer Pty Ltd) to clarify relationships within the discourse. Results: After completing a lexical analysis of 50,638 tweets, 7 key findings were identified. First, the discourse was largely devoid of references to interprofessional care. Second, there was no explicit discourse pertaining to physiotherapists. Third, although all the professions represented in this study support patients, discourse pertaining to general practitioners was most likely to be connected with that pertaining to patients. Fourth, tweets pertaining to pharmacists were most likely to be connected with discourse pertaining to latest and research. Fifth, tweets about social workers were unlikely to be connected with discourse pertaining to health or care. Sixth, notwithstanding a few exceptions, the findings across the different nations were generally similar, suggesting their generality. Seventh and last, tweets pertaining to physiotherapists were most likely to refer to discourse pertaining to profession. Conclusions: The findings indicate that health care professional associations do not use Twitter to disseminate cues that reinforce the importance of interprofessional care. Instead, they largely use this platform to emphasize what they individually deem to be important and advance the interests of their respective professions. Therefore, there is considerable opportunity for professional associations to assert how the profession they represent complements other health care professions and how the professionals they represent can enact interprofessional care for the benefit of patients and carers

Framing the financial crisis: television news, civic discussions, and maintaining consent in a time of crisis.

The aim of this thesis was to investigate the role of television news media in maintaining cultural hegemony in the United States. The financial crisis of 2008 and 2009 was used as a window into this process. For this investigation, a qualitative frame analysis was conducted on samples of television news coverage from major moments during the financial crisis and the resulting economic recession. Additionally, peer group discussions were conducted as a window into how people who fit the social and cultural imaginary of “Middle America,” an important part of the historic bloc which forms the contemporary United States cultural hegemony, discussed the financial crisis and recession in a social context. The results found five major explanatory frames which dominated coverage of the financial crisis; strategygame frame, survivor stories, bootstraps frame, opportunity in disaster, and populism. Taken in aggregate, these frames directed attention away from the actions of the economic elite and onto either the actions of politicians or the responsibilities of non-elite individuals. Moreover, these frames deprived the information environment of information which might otherwise facilitate an understanding of the financial crisis as resulting from the actions and practices of the business elite or the economic structure. Participants in the peer group discussions seemed to echo much of the picture provided by television media, demonstrating in particular a pervasive belief in a dysfunctional American government. Overall, participants struggled to demonstrate a fundamental understanding of the financial crisis, and this hindered their ability to form and express counter-ideologies. This was in spite of pervasive, emotional expression of betrayal, dissatisfaction and economic vulnerability. Overall, it is concluded that television news media functions as a hegemonic apparatus due to its practices producing frames and narratives which obscure the role of the capitalist classes even in the event of an economic crisis

Content Distribution in P2P Systems

The report provides a literature review of the state-of-the-art for content distribution. The report's contributions are of threefold. First, it gives more insight into traditional Content Distribution Networks (CDN), their requirements and open issues. Second, it discusses Peer-to-Peer (P2P) systems as a cheap and scalable alternative for CDN and extracts their design challenges. Finally, it evaluates the existing P2P systems dedicated for content distribution according to the identied requirements and challenges