Architetture, Servizi e Multimedialità nei Nuovi Media

Taking inspiration from the emergence of new potentialities proposed by the introduction of Digital Television in the national territory, the initial aim of the thesis was the study of the adaptation of audio/video and informative content for this device, that has always been the best known and the most widespread media in Italian families. The logical consequence has been an extension to the concept of multichannel modality, that would develop the same services trough several communication media, standardizing them due to facilitate their usage, moving from one media to another one. This process allows to have the widest target of users, overcoming the well-known problems of digital and knowledge divide. Firstly, wireless networks have been analyzed, in this case DVB-T broadcasting and its standards for the development of services, MHP and Teletext, showing how the different transport streams could be implemented through the OpenSource software adopted, and studying an optimization of each bit rate depending on the importance and usage rate of services. Secondly, moving on to wired networks, a survey has been carried out about different existing architectures for Next Generation Networks, focusing on pros and cons of point-to -point and PON solutions. Assuming, then, IPTV as a future killer application developed over optical networks, a research has been carried out about existing multicast routing algorithms and protocols, which are necessary for the deployment of this kind of service. Moreover a schematization through AUML has been proposed, in order to standardise the great heterogeneity of these protocols. Different types of MHP services are then presented, in compliance with arrangements that allow a weak interactivity, that is no return channel is used: informative content, navigable through a double filtering of news included; conditional acces for the visualization of sensitive data; galleries composed by alternate images and text, thought for guided tours and self-evaulation tests associated to a t-learning system. Informative services have also been developed through Teletext technology due to be available on any device, given the limited distribution of interactive decoders in Italy. Performances of this service implemented through MHP and Teletext have been measured and compared to highlight strength and weaknesses of both technologies. The totality of services, including the Teletext version, have been then proposed, with the same graphics and features, even on a website. At the same time several projects have been implemented, allowing the collection of multiple data of public interest, that could be available for citizens through the multichannel system created. For first a data Management Center for environmental monitoring has been developed: this collects data gathered from heterogeneous sensors, located throughout the regional territory, that could be correlated, providing more complex information. Furthermore, a project has been implemented due to have a joint monitoring of networks and services, thaks to the Lepida Network, collecting, standardizing, aggregating data about the network traffic and the frequency of use of some services provided through the same network. Finally, a portal born for the collection of Open Data has been implemented, at the request of the Emilia Romagna Region: this results in a point of convergence of all data gathered both by projects previously explained, and by other local institutions and organizations, providing heterogeneous information about land register, population, cartographical data, and so on. Multichannel modality has been mantained also in audio/video context. First of all a conversion chain has been studied that allows to have a hight quality even with a low bandwidth, both in case of regular TV programming and in case of live events. Morover the stream has been doubled in order to view it in simulcast on the web; in addition, audio/video content are available in On Demand mode on the same web site. Finally, critical situations regarding IPTV have been highlited and a survey has been done about which multicast protocols should be more efficient to distribute IPTV throughout the various parts of an NGN. Lastly, one more extension of the multichannel system is illustrated through the development of an audio/video streaming and an informative service, on an emerging, OpenSource, multimedia platform named OpenBOXware.