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Ohliger M.,Free University of Berlin | Ohliger M.,University of Potsdam | Nesme V.,Free University of Berlin | Nesme V.,Laboratoire Dinformatique Of Grenoble | Eisert J.,Free University of Berlin
New Journal of Physics | Year: 2013

We present a novel method for performing quantum state tomography for many-particle systems, which are particularly suitable for estimating the states in lattice systems such as of ultra-cold atoms in optical lattices. We show that the need to measure a tomographically complete set of observables can be overcome by letting the state evolve under some suitably chosen random circuits followed by the measurement of a single observable. We generalize known results about the approximation of unitary two-designs, i.e. certain classes of random unitary matrices, by random quantum circuits and connect our findings to the theory of quantum compressed sensing. We show that for ultra-cold atoms in optical lattices established experimental techniques such as optical super-lattices, laser speckles and time-of-flight measurements are sufficient to perform fully certified, assumption-free tomography. This is possible without the need to address single sites in any step of the procedure. Combining our approach with tensor network methods - in particular, the theory of matrix product states - we identify situations where the effort of reconstruction is even constant in the number of lattice sites, allowing, in principle, to perform tomography on large-scale systems readily available in present experiments. © IOP Publishing and Deutsche Physikalische Gesellschaft. Source


Pellier D.,University of Paris Descartes | Fiorino H.,Laboratoire Dinformatique Of Grenoble | Metivier M.,University of Paris Descartes
12th International Conference on Autonomous Agents and Multiagent Systems 2013, AAMAS 2013 | Year: 2013

Devising intelligent robots or agents that interact with humans is a major challenge for artificial intelligence. In such contexts, agents must constantly adapt their decisions according to human activities and modify their goal. In this extended abstract, we present a novel continual planning approach, called Moving Goal Planning (MGP) to adapt plans to goal evolutions. This approach draws inspiration from Moving Target Search (MTS) algorithms. In order to limit the number of search iterations and to improve its efficiency, MGP delays as much as possible the start of new searches when the goal changes over time. To this purpose, MGP uses two strategies: Open Check (OC) that checks if the new goal is still in the current search tree and Plan Follow (PF) that estimates whether executing actions of the current plan brings MGP closer to the new goal. Copyright © 2013, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved. Source


Chaabani M.,University of Boumerdes | Echahed R.,Laboratoire Dinformatique Of Grenoble | Strecker M.,Toulouse 1 University Capitole
CEUR Workshop Proceedings | Year: 2013

This paper is about transformations of knowledge bases with the aid of an imperative programming language which is non-standard in the sense that it features conditions (in loops and selection statements) that are description logic (DL) formulas, and a non-deterministic assignment statement (a choice operator given by a DL formula). We sketch an operational semantics of the proposed programming language and then develop a matching Hoare calculus whose pre- and post-conditions are again DL formulas. A major difficulty resides in showing that the formulas generated when calculating weakest preconditions remain within the chosen DL fragment. In particular, this concerns substitutions whose result is not directly representable. We therefore explicitly add substitution as a constructor of the logic and show how it can be eliminated by an interleaving with the rules of a traditional tableau calculus. Source


Bricon-Souf N.,CNRS Toulouse Institute in Information Technology | Verdier C.,Laboratoire Dinformatique Of Grenoble | Flory A.,INSA Lyon | Jaulent M.C.,French Institute of Health and Medical Research
IRBM | Year: 2013

This paper presents the activities of the theme C "medical information systems and databases" in the GDR Stic Santé. Six one-day workshops have been organized during the period 2011-2012. They were devoted to 1) sharing anatomical and physiological object models for simulation of clinical medical images, 2) advantages and limitations of datawarehouse for biological data, 3) medical information engineering, 4) systems for sharing medical images for research, 5) knowledge engineering for semantic interoperability in e-health applications, and 6) using context in health. In the future, our activities will continue with a specific interest on information systems for translational medicine and the role of electronic healthcare reports in decision-making. Workshops with other research groups will be organized in particular with the e-health research group. © 2013 Elsevier Masson SAS. Source


Martinet J.,Laboratoire Dinformatique Fondamentale Of Lille | Chiaramella Y.,Laboratoire Dinformatique Of Grenoble | Mulhem P.,Laboratoire Dinformatique Of Grenoble
Information Processing and Management | Year: 2011

In this paper, we lay out a relational approach for indexing and retrieving photographs from a collection. The increase of digital image acquisition devices, combined with the growth of the World Wide Web, requires the development of information retrieval (IR) models and systems that provide fast access to images searched by users in databases. The aim of our work is to develop an IR model suited to images, integrating rich semantics for representing this visual data and user queries, which can also be applied to large corpora. Our proposal merges the vector space model of IR - widely tested in textual IR - with the conceptual graph (CG) formalism, based on the use of star graphs (i.e. elementary CGs made up of a single relation connected to some concepts representing image objects). A novel weighting scheme for star graphs, based on image objects size, position, and image heterogeneity is outlined. We show that integrating relations into the vector space model through star graphs increases the system's precision, and that the results are comparable to those from graph projection systems, and also that they shorten processing time for user queries. © 2010 Elsevier Ltd. All rights reserved. Source

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