High-performance switching architectures for optical networks

The need for high bandwidth, due to the explosion of new multi\-media-oriented IP-based services, as well as increasing broadband access requirements is leading to the need of flexible and highly reconfigurable optical networks. While transmission bandwidth does not represent a limit due to the huge bandwidth provided by optical fibers and Dense Wavelength Division Multiplexing (DWDM) technology, the electronic switching nodes in the core of the network represent the bottleneck in terms of speed and capacity for the overall network. For this reason DWDM technology must be exploited not only for data transport but also for switching operations. In this Ph.D. thesis solutions for photonic packet switches, a flexible alternative with respect to circuit-switched optical networks are proposed. In particular solutions based on devices and components that are expected to mature in the near future are proposed, with the aim to limit the employment of complex components. The work presented here is the result of part of the research activities performed by the Networks Research Group at the Department of Electronics, Computer Science and Systems (DEIS) of the University of Bologna, Italy. In particular, the work on optical packet switching has been carried on within three relevant research projects: the e-Photon/ONe and e-Photon/ONe+ projects, funded by the European Union in the Sixth Framework Programme, and the national project OSATE funded by the Italian Ministry of Education, University and Scientific Research. The rest of the work is organized as follows. Chapter 1 gives a brief introduction to network context and contention resolution in photonic packet switches. Chapter 2 presents different strategies for contention resolution in wavelength domain. Chapter 3 illustrates a possible implementation of one of the schemes proposed in chapter 2. Then, chapter 4 presents multi-fiber switches, which employ jointly wavelength and space domains to solve contention. Chapter 5 shows buffered switches, to solve contention in time domain besides wavelength domain. Finally chapter 6 presents a cost model to compare different switch architectures in terms of cost.

Audiovisivi e Social Networks: il testo e i modi dell'esperienza 2007-2010

The doctoral research project "Audiovisuals and Social Networks: Text and Experiences 2007-2010" is mainly based on the analysis of the international audiovisuals landscape and of the promotional strategies of these products in Social Networks environment. The aim is to understand what kind of changes we can find about the concept of "text", users and marketing. The thesis is focused not just on Social Network marketing but also on new media development, such as Social TV and mobile.

Reti socievoli: l’impatto dei social networks nella costruzione dello spazio pubblico

La tesi si è consolidata nell’analisi dell’impatto dei social networks nella costruzione dello spazio pubblico, nella sfera di osservazione che è la rete e il web2.0. Osservando che il paradigma della società civile si sia modificato. Ridefinendo immagini e immaginari e forme di autorappresentazione sui new media (Castells, 2010). Nel presupposto che lo spazio pubblico “non è mai una realtà precostituita” (Innerarity, 2008) ma si muove all’interno di reti che generano e garantiscono socievolezza. Nell’obiettivo di capire cosa è spazio pubblico. Civic engagement che si rafforza in spazi simbolici (Sassen, 2008), nodi d’incontro significativi. Ivi cittadini-consumatori avanzano corresponsabilmente le proprie istanze per la debacle nei governi.. Cultura partecipativa che prende mossa da un nuovo senso civico mediato che si esprime nelle “virtù” del consumo critico. Portando la politica sul mercato. Cultura civica autoattualizzata alla ricerca di soluzioni alle crisi degli ultimi anni. Potere di una comunicazione che riduce il mondo ad un “villaggio globale” e mettono in relazione i pubblici connessi in spazi e tempi differenti, dando origine ad azioni collettive come nel caso degli Indignados, di Occupy Wall Street o di Rai per una notte. Emerge un (ri)pensare la citizenship secondo due paradigmi (Bennett,2008): l’uno orientato al governo attraverso i partiti, modello “Dutiful Citizenship”; l’altro, modello “Self Actualizing Citizenship” per cui i pubblici attivi seguono news ed eventi, percepiscono un minor obbligo nel governo, il voto è meno significativo per (s)fiducia nei media e nei politici. Mercato e società civile si muovono per il bene comune e una nuova “felicità”. La partecipazione si costituisce in consumerismo politico all’interno di reti in cui si sviluppano azioni individuali attraverso il social networking e scelte di consumo responsabile. Partendo dall’etnografia digitale, si è definito il modello “4 C”: Conoscenza > Coadesione > Co-partecipazione > Corresposabilità (azioni collettive) > Cultura-bility.

Media activism on and off line by Italian adolescents and young adults

From several researchers it appears that Italian adolescents and young people are grown up with commercial television which is accused to contain too much violence, sex, reality shows, advertising, cartoons which are watched from 1 to 4 hours daily. Adolescents are also great users of mobile phones and spend a lot of time to use it. Their academic results are below the average of Ocse States. However the widespread use of communication technology and social networks display also another side of adolescents who engage in media activism and political movement such as Ammazzateci tutti!, Indymedia, Movimento 5 Stelle, Movimento No Tav. In which way does the world economic crisis -with the specific problems of Italy as the cutting founds for school, academic research and welfare, the corruption of political class, mafia and camorra organisation induce a reaction in our adolescents and young people? Several researches inform us about their use of internet in terms of spending time but, more important, how internet, and the web 2.0, could be an instrument for their reaction? What do they do online? How they do it? Which is the meaning of their presence online? And, has their online activity a continuity offline? The research aims are: 1. Trough a participant observation of Social Network profiles opened by 10 young active citizens, I would seek to understand which kind of social or political activities they engage in online as individuals and which is the meaning of their presence online. 2. To observe and understand if adolescents and young people have a continuity of their socio-political engagement online in offline activities and which kind of experiences it is. 3. Try to comprehend which was (or which were) the significant, learning experiences that convinced them about the potential of the web as tool for their activism.