Unstructured P2P Link Lifetimes Redux

We revisit link lifetimes in random P2P graphs under dynamic node failure and create a unifying stochastic model that generalizes the majority of previous efforts in this direction. We not only allow nonexponential user lifetimes and age-dependent neighbor selection, but also cover both active and passive neighbor-management strategies, model the lifetimes of incoming and outgoing links, derive churn-related message volume of the system, and obtain the distribution of transient in/out degree at each user. We then discuss the impact of design parameters on overhead and resilience of the network

Unstructured P2P link lifetimes redux

We revisit link lifetimes in random P2P graphs under dynamic node failure and create a unifying stochastic model that generalizes the majority of previous efforts in this direction. We not only allow non-exponential user lifetimes and age-dependent neighbor selection, but also cover both active and passive neighbor-management strategies, model the lifetimes of incoming and outgoing links, derive churn-related message volume of the system, and obtain the distribution of transient in/out degree at each user. We then discuss the impact of design parameters on overhead and resilience of the network

Resistance commons : file-sharing litigation and the social system of commoning

textThis dissertation is an investigation into the practice of peer-to-peer file-sharing and the litigation campaign targeting individual file-sharers carried out by the Recording Industry Association of America (RIAA) from 2003 to 2008. The competing conceptualizations of social relations which motivate the conflict over peer-to-peer file-sharing are explored using a combination of Autonomist Marxist theory and structuration theory. Peer-to-peer file-sharing is framed as part of the social system of commoning stemming from the recent ascendancy of immaterial labor within that sector of the economy dedicated to the production and distribution of informational and cultural goods. The RIAA litigation campaign is framed as a reaction to the emergence of new forms of social relations which are seen by the content-producing industries as subversive of revenue streams premised on commodity exchange in informational and cultural goods. The history of the RIAA litigation campaign is presented in detail with careful attention given to those instances in which defendants and other interested parties fought back against RIAA legal actions. The acts of resistance within the legal arena affected the ultimate potential of the litigation campaign to control the spread of file-sharing activities. Subsequent legal campaigns which have been based on the RIAA litigation model are also examined. These later file-sharing cases have been met with similar forms of resistance which have likewise mitigated the impact of legal efforts to combat file-sharing. In addition, a survey of file-sharers is included in this research as part of an attempt to understand the relationship between legal actions targeting peer-to-peer systems and individual file-sharers and the technological and social development of peer-to-peer systems. This research argues that file-sharing litigation has proven ineffective in turning back the flood of file-sharing and may have increased the technological sophistication and community ties among file-sharers. In the end, the conflict over peer-to-peer file-sharing is cast as a manifestation of a larger dynamic of capitalist crisis as content-producing industries attempt to come to terms with the contradictory tendencies of immaterial labor and the production of common pools of digital resources.Radio-Television-Fil

Building blocks for semantic data organization on the desktop

Die Organisation von (Multimedia-) Daten auf Desktop-Systemen wird derzeit hauptsächlich durch das Einordnen von Dateien in ein hierarchisches Dateisystem bewerkstelligt. Zusätzlich werden gewisse Inhalte (z.B. Musik oder Fotos) von spezialisierter Software mit Hilfe Datei-bezogener Metadaten verwaltet. Diese Metadaten werden meist direkt im Dateikopf in einer Unzahl verschiedener, vorwiegend proprietärer Formate gespeichert. Allgemein nehmen Metadaten und Links die Schlüsselrollen in fortgeschrittenen Datenorganisationskonzepten ein, ihre eingeschränkte Unterstützung in vorherrschenden Dateisystemen macht die Einführung solcher Konzepte auf dem Desktop jedoch schwierig: Erstens müssen Anwendungen sowohl Dateiformat als auch Metadatenschema verstehen um auf Metadaten zugreifen zu können; zweitens ist ein getrennter Zugriff auf Daten und Metadaten nicht möglich und drittens kann man solche Metadaten nicht mit mehreren Dateien oder mit Dateiordnern assoziieren obgleich letztere die derzeit wichtigsten Konstrukte für die Dateiorganisation darstellen. Dies bedeutet in weiterer Folge: (i) eingeschränkte Möglichkeiten der Datenorganisation, (ii) eingeschränkte Navigationsmöglichkeiten, (iii) schlechte Auffindbarkeit der gespeicherten Daten, und (iv) Fragmentierung von Metadaten. Obschon es Versuche gab, diese Situation (zum Beispiel mit Hilfe semantischer Dateisysteme) zu verbessern, wurden die meisten dieser Probleme bisher vor allem im Web und im Speziellen im semantischen Web adressiert und gelöst. Das Anwenden dort entwickelter Lösungen auf dem Desktop, einer zentralen Plattform der Daten- und Metadatenmanipulation, wäre zweifellos von Vorteil. In der vorliegenden Arbeit wird ein neues, rückwärts-kompatibles Metadatenmodell als Lösungsversuch für die oben genannten Probleme präsentiert. Dieses Modell basiert auf stabilen Datei-Identifikatoren und externen, semantischen, Datei- bezogenen Metadatenbeschreibungen welche im RDF Graphenmodell repräsentiert werden. Diese Beschreibungen sind durch eine einheitliche Linked-Data- Schnittstelle zugänglich und können mit anderen Beschreibungen und Ressourcen verlinkt werden. Im Speziellen erlaubt dieses Modell semantische Links zwischen lokalen Dateisystemobjekten und Netzressourcen im Web sowie im entstehenden “Daten Web” und ermöglicht somit die Integration dieser Datenräume. Das Modell hängt entscheidend von der Stabilität dieser Links ab weshalb zwei Algorithmen präsentiert werden, welche deren Integrität in lokalen und vernetzten Umgebungen erhalten können. Dies bedeutet, dass Links zwischen Dateisystemobjekten, Metadatenbeschreibungen und Netzressourcen nicht brechen wenn sich deren Adressen ändern, z.B. wenn Dateien verschoben oder Linked-Data Ressourcen unter geänderten URIs publiziert werden. Schließlich wird eine prototypische Implementierung des vorgeschlagenen Metadatenmodells präsentiert, welche demonstriert wie die Summe dieser Bausteine eine Metadatenschicht bildet die als Grundlage für semantische Datenorganisation auf dem Desktop verwendet werden kann.The organization of (multimedia) data on current desktop systems is done to a large part by arranging files in hierarchical file systems, but also by specialized applications (e.g., music or photo organizing software) that make use of file-related metadata for this task. These metadata are predominantly stored in embedded file headers, using a magnitude of mainly proprietary formats. Generally, metadata and links play the key roles in advanced data organization concepts. Their limited support in prevalent file system implementations, however, hinders the adoption of such concepts on the desktop: First, non-uniform access interfaces require metadata consuming applications to understand both a file’s format and its metadata scheme; second, separate data/metadata access is not possible, and third, metadata cannot be attached to multiple files or to file folders although the latter are the primary constructs for file organization. As a consequence of this, current desktops suffer, inter alia, from (i) limited data organization possibilities, (ii) limited navigability, (iii) limited data findability, and (iv) metadata fragmentation. Although there were attempts to improve this situation, e.g., by introducing semantic file systems, most of these issues were successfully addressed and solved in the Web and in particular in the Semantic Web and reusing these solutions on the desktop, a central hub of data and metadata manipulation, is clearly desirable. In this thesis a novel, backwards-compatible metadata model that addresses the above-mentioned issues is introduced. This model is based on stable file identifiers and external, file-related, semantic metadata descriptions that are represented using the generic RDF graph model. Descriptions are accessible via a uniform Linked Data interface and can be linked with other descriptions and resources. In particular, this model enables semantic linking between local file system objects and remote resources on the Web or the emerging Web of Data, thereby enabling the integration of these data spaces. As the model crucially relies on the stability of these links, we contribute two algorithms that preserve their integrity in local and in remote environments. This means that links between file system objects, metadata descriptions and remote resources do not break even if their addresses change, e.g., when files are moved or Linked Data resources are re-published using different URIs. Finally, we contribute a prototypical implementation of the proposed metadata model that demonstrates how these building blocks sum up to constitute a metadata layer that may act as a foundation for semantic data organization on the desktop

(In)formal perceptions and arguments on tourism governance multifaceted concept

A brief exploratory approach to (in)formal perceptions and arguments on tourism governance multifaceted concep

Knowledge and Management Models for Sustainable Growth

In the last years sustainability has become a topic of global concern and a key issue in the strategic agenda of both business organizations and public authorities and organisations. Significant changes in business landscape, the emergence of new technology, including social media, the pressure of new social concerns, have called into question established conceptualizations of competitiveness, wealth creation and growth. New and unaddressed set of issues regarding how private and public organisations manage and invest their resources to create sustainable value have brought to light. In particular the increasing focus on environmental and social themes has suggested new dimensions to be taken into account in the value creation dynamics, both at organisations and communities level. For companies the need of integrating corporate social and environmental responsibility issues into strategy and daily business operations, pose profound challenges, which, in turn, involve numerous processes and complex decisions influenced by many stakeholders. Facing these challenges calls for the creation, use and exploitation of new knowledge as well as the development of proper management models, approaches and tools aimed to contribute to the development and realization of environmentally and socially sustainable business strategies and practices

Disseny d'un model d'avaluació de resultats de l'activitat de màrqueting per a empreses competint al mercat català i amb relació contractual amb els seus clients

L’objectiu de la tesi doctoral és el de desenvolupar un model que permeti valorar de forma objectiva les actuacions en matèria de màrqueting portades a terme per una organització. Aquest model està constituït per un conjunt de variables descriptives i quantitatives, anomenades variables de control, juntament amb una metodologia de càlcul i un sistema d’indicadors integrat que facilita la traçabilitat de les inversions de màrqueting i explicita la relació causa-efecte entre aquestes i el valor generat per a l’organització. El model s’utilitza per a valorar dades reals d’organitzacions que operin al mercat català i que compleixin la condició de basar la relació amb els seus clients en un model contractual (com veurem més endavant, és inviable aplicar un model comú per a tot tipus d’empresa). L’objectiu, doncs, és la valoració de l’acompliment dels seus objectius en relació als seus actius de mercat (marca i valor de client) i la creació d’un model específic, no generalitzable, per a aquest tipus d’empreses. Un segon objectiu d’aquest treball és l’anàlisi de les principals publicacions especialitzades referents des d’un punt de vista global i local, proposant en primer lloc una terminologia clara en relació a l’activitat de màrqueting, l’acompliment dels seus objectius i la conceptualització d’actius de mercat, i analitzant, en segon, l’impacte d’aquests àmbits i la seva evolució en els últims quinze anys. Alguns estudis previs (Llonch et al., 2002; Ambler i Xiucun, 2003; entre d’altres) es centren a comparar empreses per sectors, funcionalitats i països. És probable, com apunta Llonch et al. (2002) al fer això, que casuístiques atribuïbles a diferències geogràfiques i nacionals es tractin erròniament com a empresarials. A tal efecte, aquest estudi elimina la variabilitat per país i sector (parcialment, aquest darrer), proposant un model acotat, tal com recomanen Ambler et al., (2001), Llonch et al (2002), entre d’altres, que pugui servir de referència en la metodologia i en la validesa conceptual, i no tant en els resultats del model en un context més genèric. Pauwels (2009) demostra la relació entre la creació d’un model predefinit de variables i la millora del càlcul de l’eficiència en la despesa en màrqueting, pel que la creació d’aquest model integrat té l’objectiu d’esdevenir una eina de Gestió del Rendiment Corporatiu (GRC, en endavant1) (Bauer, 2004) aplicada a la gestió de màrqueting i els seus actius. Aquesta particularització del GRC rep el nom de Gestió del Rendiment de Màrqueting (GRM, en endavant2) (Ambler, 2000) i el seu objectiu és el d’augmentar la usabilitat i faciliti la generació d’informació per a la presa de decisions de la línia directiva de les organitzacions. L’abast de la tesi és el de crear el model des d’una perspectiva d’avaluació de l’activitat de màrqueting per part de la línia directiva, i no pas el desenvolupament informàtic d’una eina de suport a la presa de decisions ja que això, com apunten diversos autors (Dover, 2004; Schiff, 2008) i es tractarà amb més profunditat en el capítol 5, implicaria un nivell de personalització per cada empresa que no és objectiu d’aquesta tesi.The thes is aims to develop a practical model to asses m arketing perform ance within an organization. The model is basically structured around control metrics both from a qualitative and quantitatve approach, together with an integrated system of key performance indicators that enables marketing accountability through different organisational divisions, thus stating a solid cause/effect relationship between marketing activities and the value created for the organisation. The aformentioned model is used to assess marketing activites for catalan com panies with a contract-based customer relationship. Final assessment includes also a dynamic valuation of the company's market as sets . A second objective of the thes is is to review the current state of the art of marketing assessment literature from specialized journals both from a global and a local pers pective, defining a comprehensive list of related terms about marketing performance measurement, market-asset description and valuation and an accurate analysis about its evolution throughout the last 15 years.Postprint (published version