Ara es mostren els items 77-90 de 90

    • Rehabilitation profiles of older adult stroke survivors admitted to intermediate care units: A multi-centre study 

      Pérez, Laura M.; Inzitari, Marco; Quinn, Terence J.; Montaner, Joan; Gavaldà Mestre, Ricard; Duarte, Esther; Coll Planas, Laura; Cerdá, Mercé; Santaeugenia, Sebastia; Closa, Conxita; Gallofre, Miquel (2016-11-09)
      Article
      Accés obert
      Background: Stroke is a major cause of disability in older adults, but the evidence around post-acute treatment is limited and heterogeneous. We aimed to identify profiles of older adult stroke survivors admitted to ...
    • Relativized separations of polynomial space and exponential time 

      Gavaldà Mestre, Ricard (1991-11-19)
      Report de recerca
      Accés obert
      We present several applications of generalized Kolmogorov complexity to the construction of oracles separating complexity classes. We choose as examples of application the classes PSPACE, NPSPACE, and EXPTIME, and present ...
    • Resolution of NP-complete problems 

      Gavaldà Mestre, Ricard (1995-06-03)
      Report de recerca
      Accés obert
      These are the course notes for my lectures on "Resolution of NP-complete problems". These lectures are a part of the Sixth Advanced Course on Artificial Intelligence, ACAI'95, which this year is devoted to AI Algorithmics, ...
    • Sequential sampling algorithms: unified analysis and lower bounds 

      Gavaldà Mestre, Ricard; Watanabe, Osamu (2001-11)
      Report de recerca
      Accés obert
      Sequential sampling algorithms have recently attracted interest as a way to design scalable algorithms for Data mining and KDD processes. In this paper, we identify an elementary sequential sampling task (estimation from ...
    • Some structural complexity aspects of neural computation 

      Balcázar Navarro, José Luis; Gavaldà Mestre, Ricard; Siegelmann, H.; Sontag, Eduardo D. (1992)
      Report de recerca
      Accés obert
      Recent work by Siegelmann and Sontag has demonstrated that polynomial time on linear saturated recurrent neural networks equas polynomial time on standard computational models: Turing machines if the weights of the net are ...
    • Strong and robustly strong polynomial time reducibilities to sparse sets 

      Gavaldà Mestre, Ricard; Balcázar Navarro, José Luis (1988)
      Report de recerca
      Accés obert
      Reducibility defined by oracle strong nondeterministic machines is studied. Two definitions of relativized strength are presented and separated. The corresponding reduction classes of the sparse sets give two nonuniform ...
    • Structural analysis of polynomial time query learnability 

      Watanabe, Osamu; Gavaldà Mestre, Ricard (1992-03-12)
      Report de recerca
      Accés obert
      For some representation classes, we relate its polynomial time query learnability to the complexity of representation finding problems of P/poly oracles. For example, for CIR, a representation class by logical circuits, ...
    • The complexity of learning with queries 

      Gavaldà Mestre, Ricard (1994-04-14)
      Report de recerca
      Accés obert
      We survey recent research concerning the qualitative complexity of Angluin's model of learning with queries. In this model, there is a learner that tries to identify a target concept by means of queries to a teacher. Thus, ...
    • The frequency spectrum of finite samples from the intermittent silence process 

      Ferrer Cancho, Ramon; Gavaldà Mestre, Ricard (2009-04)
      Article
      Accés obert
      It has been argued that the actual distribution of word frequencies could be reproduced or explained by generating a random sequence of letters and spaces according to the so-called intermittent silence process. The same ...
    • Towards energy-aware scheduling in data centers using machine learning 

      Berral García, Josep Lluís; Goiri Presa, Íñigo; Nou Castell, Ramon; Julià, Ferran; Guitart Fernández, Jordi; Gavaldà Mestre, Ricard; Torres Viñals, Jordi (2010-04-15)
      Text en actes de congrés
      Accés obert
      As energy-related costs have become a major economical factor for IT infrastructures and data-centers, companies and the research community are being challenged to nd better and more efficient power-aware resource ...
    • Tractabilitat de NP i altres classes de complexitat per famílies de circuits booleans 

      Gavaldà Mestre, Ricard (1987-11)
      Report de recerca
      Accés obert
      We search for nonuniform analogs of the complexity class N P ¿ coN P. Following mainly the work of Karp and Lipton on these classes, 1) We define two types of polynomial time reducibility, study some of their basic properties ...
    • Tractable clones of polynomials over semigroups 

      Dalmau, Víctor; Gavaldà Mestre, Ricard; Tesson, Pascal; Thérien, Denis (2005-12)
      Report de recerca
      Accés obert
      We contribute to the algebraic study of the complexity of constraint satisfaction problems. We give a new sufficient condition on a set of relations R over a domain S for the tractability of CSP(R): if S is a block-group ...
    • Una altra demostració del teorema de Cook 

      Gavaldà Mestre, Ricard (1993-06-04)
      Report de recerca
      Accés obert
      Presentem una demostració alternativa del Teorema de Cook: saber si una fòrmula booleana és satisfactible és un problema NP-complet. La demostració es diferencia de les altres que conec en dos aspectes. Un, que defineixo ...
    • Using fewer examples to simulate equivalence queries 

      Gavaldà Mestre, Ricard (1996-03-02)
      Report de recerca
      Accés obert
      It is well known that an algorithm that learns exactly using Equivalence queries can be transformed into a PAC algorithm that asks for random labelled examples. The first transformation due to Angluin (1988) uses a ...