4,163 research outputs found
From Bosonic Grand-Canonical Ensembles to Nonlinear Gibbs Measures
In a recent paper, in collaboration with Mathieu Lewin and Phan Th{\`a}nh
Nam, we showed that nonlinear Gibbs measures based on Gross-Pitaevskii like
functionals could be derived from many-body quantum mechanics, in a mean-field
limit. This text summarizes these findings. It focuses on the simplest, but
most physically relevant, case we could treat so far, namely that of the
defocusing cubic NLS functional on a 1D interval. The measure obtained in the
limit, which (almost) lives over H^{1/2} , has been previously shown to be
invariant under the NLS flow by Bourgain.Comment: This is the text of a Laurent Schwartz X-EDP seminar I gave in
November 2014. It summarizes some of the results of arXiv:1410.033
General covariance of the non-abelian DBI-action: Checks and Balances
We perform three tests on our proposal to implement diffeomorphism invariance
in the non-abelian D0-brane DBI action as a basepoint independence constraint
between matrix Riemann normal coordinate systems. First we show that T-duality
along an isometry correctly interchanges the potential and kinetic terms in the
action. Second, we show that the method to impose basepoint independence using
an auxiliary dN^2-dimensional non-linear sigma model also works for metrics
which are curved along the brane, provided a physical gauge choice is made at
the end. Third, we show that without alteration this method is applicable to
higher order in velocities. Testing specifically to order four, we elucidate
the range of validity of the symmetrized trace approximation to the non-abelian
DBI action.Comment: LaTeX, 22 page
Temporal Feature Selection with Symbolic Regression
Building and discovering useful features when constructing machine learning models is the central task for the machine learning practitioner. Good features are useful not only in increasing the predictive power of a model but also in illuminating the underlying drivers of a target variable. In this research we propose a novel feature learning technique in which Symbolic regression is endowed with a ``Range Terminal\u27\u27 that allows it to explore functions of the aggregate of variables over time. We test the Range Terminal on a synthetic data set and a real world data in which we predict seasonal greenness using satellite derived temperature and snow data over a portion of the Arctic. On the synthetic data set we find Symbolic regression with the Range Terminal outperforms standard Symbolic regression and Lasso regression. On the Arctic data set we find it outperforms standard Symbolic regression, fails to beat the Lasso regression, but finds useful features describing the interaction between Land Surface Temperature, Snow, and seasonal vegetative growth in the Arctic
Software as a service: Undo
This paper proposes a highly automated mechanism to build an undo facility into a new or existing system easily. Our
proposal is based on the observation that for a large set of
operators it is not necessary to store in-memory object states or executed system commands to undo an action; the storage of input data is instead enough. This strategy simplifies greatly the design of the undo process and encapsulates most of the functionalities required in a framework structure similar to the many object-oriented programming frameworks
Service Oriented Architecture for Undo Functionality
This paper proposes a highly automated mechanism to build an undo facility into a new or existing system easily encapsulated into a service. Our proposal is based on the observation that for a large set of operators it is not necessary to store in-memory object states or executed system commands to undo an action; the storage of input data is instead enough. The use of services strategy simplifies greatly the design of the undo process and encapsulates most of the functionalities required in a framework structure similar to the many object-oriented programming frameworks. We present a proof of concept illustrating the simplicity and reusability of the proposed framework under alignments of Software as a Service.Trabajo presentado en el VI International Conference on Research and Practical Issues of Enterprise Information Systems, realizado del 19 al 21 de septiembre en Bélgica
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