http://hdl.handle.net/2117/334 Fri, 24 May 2013 09:31:19 GMT 2013-05-24T09:31:19Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/16429 Title: Economía de la accesibilidad 20+20 : marco teórico Authors: Guasch Murillo, Daniel; Berbegal Mirabent, Jasmina; Villalta, Marta Wed, 05 Sep 2012 07:41:05 GMT http://hdl.handle.net/2117/16429 2012-09-05T07:41:05Z Guasch Murillo, Daniel; Berbegal Mirabent, Jasmina; Villalta, Marta no http://hdl.handle.net/2117/11184 Title: Influence maximization in social Networks when negative opinions may emerge and propagate Authors: Yuan, Yifei; Wei, Wei; Chen, Wei; Collins, Alex; Cummings, Rachel; Ke, Te; Liu, Zhenming; Rincón Rivera, David; Sun, Xiaorui; Wang, Yajun Abstract: Influence maximization, defined by Kempe, Kleinberg, and Tardos (2003), is the problem of finding a small set of seed nodes in a social network that maximizes the spread of influence under certain influence cascade models. In this paper, we propose an extension to the independent cascade model that incorporates the emergence and propagation of negative opinions. The new model has an explicit parameter called quality factor to model the natural behavior of people turning negative to a product due to product defects. Our model incorporates negativity bias (negative opinions usually dominate over positive opinions) commonly acknowledged in the social psychology literature. The model maintains some nice properties such as submodularity, which allows a greedy approximation algorithm for maximizing positive influence within a ratio of 1 􀀀 1=e. We define a quality sensitivity ratio (qs-ratio) of influence graphs and show a tight bound of ( p n=k) on the qs-ratio, where n is the number of nodes in the network and k is the number of seeds selected, which indicates that seed selection is sensitive to the quality factor for general graphs. We design an efficient algorithm to compute influence in tree structures, which is nontrivial due to the negativity bias in the model. We use this algorithm as the core to build a heuristic algorithm for influence maximization for general graphs. Through simulations, we show that our heuristic algorithm has matching influence with a standard greedy approximation algorithm while being orders of magnitude faster. Tue, 25 Jan 2011 07:59:07 GMT http://hdl.handle.net/2117/11184 2011-01-25T07:59:07Z Yuan, Yifei; Wei, Wei; Chen, Wei; Collins, Alex; Cummings, Rachel; Ke, Te; Liu, Zhenming; Rincón Rivera, David; Sun, Xiaorui; Wang, Yajun no Influence maximization, Social networks, Negative opinions, Independent cascade model Influence maximization, defined by Kempe, Kleinberg, and Tardos (2003), is the problem of finding a small set of seed nodes in a social network that maximizes the spread of influence under certain influence cascade models. In this paper, we propose an extension to the independent cascade model that incorporates the emergence and propagation of negative opinions. The new model has an explicit parameter called quality factor to model the natural behavior of people turning negative to a product due to product defects. Our model incorporates negativity bias (negative opinions usually dominate over positive opinions) commonly acknowledged in the social psychology literature. The model maintains some nice properties such as submodularity, which allows a greedy approximation algorithm for maximizing positive influence within a ratio of 1 􀀀 1=e. We define a quality sensitivity ratio (qs-ratio) of influence graphs and show a tight bound of ( p n=k) on the qs-ratio, where n is the number of nodes in the network and k is the number of seeds selected, which indicates that seed selection is sensitive to the quality factor for general graphs. We design an efficient algorithm to compute influence in tree structures, which is nontrivial due to the negativity bias in the model. We use this algorithm as the core to build a heuristic algorithm for influence maximization for general graphs. Through simulations, we show that our heuristic algorithm has matching influence with a standard greedy approximation algorithm while being orders of magnitude faster. http://hdl.handle.net/2117/6750 Title: La Internet del Futur: Anàlisi retrospectiva, reflexió i posicionament estratègic Authors: Serra Hurtado, Arturo; Alcober Segura, Jesús Ángel; Cervelló Pastor, Cristina; Domingo Pascual, Jordi; Fernández, Gabriel; Junyent Giralt, Gabriel; Oliver, Miquel; Paradells Aspas, Josep; Sallent Ribes, Sebastián Abstract: Aquest treball té com a objectiu analitzar la situació actual de la Internet, per proposar noves alternatives i dibuixar un possible camí cap a la Internet del Futur. Aquesta anàlisi vol ser un punt de partida, un document de reflexió, que posicioni als agents locals i nacionals (entorns de la recerca, innovació i producció, i usuaris) en una situació capdavantera en la construcció del nou model econòmic i social del segle XXI. El treball consta de dos grans apartats, una introducció descriptiva i conceptual del paper que juga la Internet i la seva projecció futura, i una segona part on es desdibuixen en mes profunditat les bases tecnològiques de la possible Internet del futur a partir de la realitat actual. Mon, 22 Mar 2010 13:21:16 GMT http://hdl.handle.net/2117/6750 2010-03-22T13:21:16Z Serra Hurtado, Arturo; Alcober Segura, Jesús Ángel; Cervelló Pastor, Cristina; Domingo Pascual, Jordi; Fernández, Gabriel; Junyent Giralt, Gabriel; Oliver, Miquel; Paradells Aspas, Josep; Sallent Ribes, Sebastián no Aquest treball té com a objectiu analitzar la situació actual de la Internet, per proposar noves alternatives i dibuixar un possible camí cap a la Internet del Futur. Aquesta anàlisi vol ser un punt de partida, un document de reflexió, que posicioni als agents locals i nacionals (entorns de la recerca, innovació i producció, i usuaris) en una situació capdavantera en la construcció del nou model econòmic i social del segle XXI. El treball consta de dos grans apartats, una introducció descriptiva i conceptual del paper que juga la Internet i la seva projecció futura, i una segona part on es desdibuixen en mes profunditat les bases tecnològiques de la possible Internet del futur a partir de la realitat actual. http://hdl.handle.net/2117/6491 Title: HdViPEr - High definition Videoconferencing over iP Environment Authors: Alcober Segura, Jesús Ángel; Mateu, Francesc; Pawalowski, Piotr Abstract: Notícia a l'Eurescom mess@ge 1/2009 - pàgina 7 Fri, 26 Feb 2010 16:35:56 GMT http://hdl.handle.net/2117/6491 2010-02-26T16:35:56Z Alcober Segura, Jesús Ángel; Mateu, Francesc; Pawalowski, Piotr no Notícia a l'Eurescom mess@ge 1/2009 - pàgina 7 http://hdl.handle.net/2117/2022 Title: Media Layer: redesigning the Internet as the media network of the future Authors: Miguélez Ortiz, Xavier; Iglesias Gracia, Francisco Javier; Lorente Adamuz, Pedro; Alcober Segura, Jesús Ángel; Serra Hurtado, Arturo; Sallent Ribes, Sebastián Mon, 19 May 2008 14:08:48 GMT http://hdl.handle.net/2117/2022 2008-05-19T14:08:48Z Miguélez Ortiz, Xavier; Iglesias Gracia, Francisco Javier; Lorente Adamuz, Pedro; Alcober Segura, Jesús Ángel; Serra Hurtado, Arturo; Sallent Ribes, Sebastián no Future network, Media, Network architecture, Media layer, Transport stream