| Links' Seminars and Public Events |   |
Mon, January 9, 2017 to Fri, January 13, 2017 all day | Visite Michael vanden Boom, Oxford University |
Fri, December 9, 2016 all day | Kickoff Headwork  Paris MNHN |
Fri, November 18, 2016 10:30 am 12:00 pm | Florent Capelli Links Seminar "Lille-Salle B21" |
Fri, November 18, 2016 all day | Florent Capelli visit |
Tue, November 8, 2016 2:30 pm 4:30 pm | Seminar Link by Helmut Seidl: "Equivalence of Deterministic Top-Down Tree-to-String Transducers is Decidable" Abstract: We show that equivalence of deterministic top-down tree-to-string transducers is decidable, thus solving a long standing open problem in formal language theory. We also present efficient algorithms for subclasses: polynomial time for total transducers with unary output alphabet (over a given top-down regular domain language), and co-randomized polynomial time for linear transducers, these results are obtained using techniques from multi-linear algebra. For our main result, we prove that equivalence can be certified by means of inductive invariants using polynomial ideals. This allows us to construct two semi-algorithms, one searching for a proof of equivalence, one for a witness of non-equivalence. "Lille-Salle B31 " |
Mon, November 7, 2016 2:00 pm 4:00 pm | PhD defense Adrien Boiret |
Fri, November 4, 2016 all day | colis general meeting Paris |
Thu, October 27, 2016 10:00 am 6:00 pm | Links day |
Thu, October 27, 2016 all day | links day |
Thu, October 20, 2016 2:00 pm 4:00 pm | Seminar Links by Vincent Hugot: "Top-Down Transducers for Data Trees" Abstract: Tree transducers have a wide range of application domains ranging from compiler construction, program analysis, and computational linguistics, to semi-structured databases and file system transformations. A common application of these domains is to specify and verify transformations of data trees, i.e., trees whose nodes are labeled by data values from an infinite domain. Most existing classes of tree transducers and their formal studies, however, are restricted to trees over finite signatures without data. In this paper, we lift the most prominent class of top-down tree transducers to data trees, such that its good properties are preserved. In particular, we show that top-down transducers for data trees have a decidable equivalence problem, without imposing any linearity restriction as in previous approaches based on symbolic top-down tree transducers. "Lille-Salle B21" |
Thu, October 13, 2016 2:00 pm 5:30 pm | comité de projet |
Thu, October 13, 2016 2:00 pm 3:00 pm | Seminar Christof Löding "Lille-Salle B21" |
Thu, October 13, 2016 to Fri, October 14, 2016 all day | visit christof löding |
Fri, September 30, 2016 all day | arrivée de Jose Lozano |
Thu, September 29, 2016 2:00 pm 4:00 pm | Seminar Links by Aurélien Lemay "Lille-Salle B21" |
Tue, September 27, 2016 all day | Ircica fetes ces 10 ans Lille |
Fri, September 9, 2016 2:00 pm 4:00 pm | Momar Sakho "Lille-Salle B21" |
Wed, September 7, 2016 11:00 am 12:00 pm | jason demagoj |
Wed, August 31, 2016 10:00 am 1:00 pm | Links Seminar by Domagoj Vrgoč: "Querying Graph with Data" "Lille-Salle B21" |
Thu, July 28, 2016 all day | Visit of Serge Abiteboul and Victor Vianu |
Mon, July 11, 2016 to Tue, July 12, 2016 all day | Aggreg meeting Marseille |
Mon, June 27, 2016 all day | Colis ANR project: general meeting Inria Paris, Salle 119 "Ada Lovelace" |
Fri, June 24, 2016 2:00 pm 4:00 pm | Fatima Belkouch: on the hypercube algorithm for conjunctive queries Abstract: We consider the problem of computing a conjunctive query on a large database in a parallel setting with p servers. Unlike traditional query processing, the complexity is no longer dominated by the number of disk accesses. Typically, a query is evaluated by a sufficiently large number of servers such that the entire data can be kept in the main memory of these servers. The dominant cost becomes that of communicating data and synchronizing among the servers. I will present some interesting results in [1, 2, 3, 4] dealing with the communication complexity of massively parallel computation of a query. The computation is performed in "rounds". First, I will present the Massively Parallel Communication (MPC) model to analyze the tradeoff between the number of rounds and the amount of communication required in a massively parallel computing environment. Then I will present the HyperCube (HC) algorithm that computes a full conjunctive query q in one round. I will discuss the communication complexity [2]. The main result is the optimal load O(m/p1/τ ) where τ is the fractional vertex cover of the hypergraph of q and m the input data size. References [1] Parallel Evaluation of Conjunctive Queries. Paris Koutris, Dan Suciu PODS2011 [2] Communication Steps for Parallel Query Processing. Paul Beame, Paris Koutris, Dan Suciu PODS2013 [3] Skew in Parallel Query Processing. Paul Beame, Paris Koutris Dan Suciu PODS'2014 [4] Worst-Case Optimal Algorithms for Parallel Query Processing. Paris Koutris, Paul Beame, Dan Suciu ICDT2016 "Lille-Salle B11" |
