pinecone/core-2020-05-10-deduplication huggingface dataset:
sine-Gordon Equation: From Discrete to Continuum

In the present Chapter, we consider two prototypical Klein-Gordon models: the
integrable sine-Gordon equation and the non-integrable $\phi^4$ model. We
focus, in particular, on two of their prototypical solutions, namely the
kink-like heteroclinic connections and the time-periodic, exponentially
localized in space breather waveforms. Two limits of the discrete variants of
these models are contrasted: on the one side, the analytically tractable
original continuum limit, and on the opposite end, the highly discrete,
so-called anti-continuum limit of vanishing coupling. Numerical computations
are used to bridge these two limits, as regards the existence, stability and
dynamical properties of the waves. Finally, a recent variant of this theme is
presented in the form of $\mathcal{PT}$-symmetric Klein-Gordon field theories
and a number of relevant results are touched upon.Comment: Book chapter; 17 pages, 10 figure
PPSA: A tool for suboptimal control of time delay systems: Revision and open tasks

Abstract During the development of algebraic controller design in a special ring for time delay systems (TDSs) a problem of a suitable free controller parameters setting appeared. The first author of this contribution recently suggested a natural idea of placing the dominant characteristic numbers (poles) and zeros of the infinite-dimensional feedback control system on the basis of the desired overshoot for a simple finite-dimensional matching model and shifting of the rest of the spectrum. However, the original procedure called the Pole-Placement Shifting based controller tuning Algorithm (PPSA) was not developed and described entirely well. The aim of this paper is to revise the idea of the PPSA and suggest a possible ways how to improve or extend the algorithm. A concise illustrative example is attached to clarify the procedure for the reader as well
Nonequilibrium and irreversibility

The booklet contain an overview on selected recent developments in
nonequilibrium statistical mechanics and chaos theory: SRB distributions,
chaotic hypothesis, fluctuation theorem, proposals for tests and applications
to granular materials, fluidodynamics, irreversibility of quasi static
processes. In appendices examples of the kind of technical work necessary for
actual construction of nonequilibrium stationary states.Comment: XI+247 pages, latex, V.2 with new references and typos eliminated V.3
  references added, further typos eliminated, style adjustment
Non-Linear Effects in Non-Kerr spacetimes

There is a chance that the spacetime around massive compact objects which are
expected to be black holes is not described by the Kerr metric, but by a metric
which can be considered as a perturbation of the Kerr metric. These non-Kerr
spacetimes are also known as bumpy black hole spacetimes. We expect that, if
some kind of a bumpy black hole exists, the spacetime around it should possess
some features which will make the divergence from a Kerr spacetime detectable.
One of the differences is that these non-Kerr spacetimes do not posses all the
symmetries needed to make them integrable. We discuss how we can take advantage
of this fact by examining EMRIs into the Manko-Novikov spacetime.Comment: 8 pages, 3 Figures; to appear in the proceedings of the conference
  "Relativity and Gravitation: 100 Years after Einstein in Prague" (2012
Geodesic deviation in Kundt spacetimes of any dimension

Using the invariant form of the equation of geodesic deviation, which
describes relative motion of free test particles, we investigate a general
family of D-dimensional Kundt spacetimes. We demonstrate that local influence
of the gravitational field can be naturally decomposed into Newton-type tidal
effects typical for type II spacetimes, longitudinal deformations mainly
present in spacetimes of algebraic type III, and type N purely transverse
effects corresponding to gravitational waves with D(D-3)/2 independent
polarization states. We explicitly study the most important examples, namely
exact pp-waves, gyratons, and VSI spacetimes. This analysis helps us to clarify
the geometrical and physical interpretation of the Kundt class of nonexpanding,
nontwisting and shearfree geometries.Comment: 8 pages, 2 figures, to appear in the Proceedings of the conference
  "Relativity and Gravitation, 100 Years after Einstein in Prague", Prague,
  June 25-29, 201
Concordance Cosmology with Particle Creation

A constant-rate creation of dark particles in the late-time FLRW spacetime
provides a cosmological model in accordance with precise observational tests.
The matter creation backreaction implies in this context a vacuum energy
density scaling linearly with the Hubble parameter, which is consistent with
the vacuum expectation value of the QCD condensate in a low-energy expanding
spacetime. Both the cosmological constant and coincidence problems are
alleviated in this scenario. We discuss the cosmological model that arises in
this context and present a joint analysis of observations of the first acoustic
peak in the cosmic microwave background (CMB) anisotropy spectrum, the Hubble
diagram for supernovas of type Ia (SNIa), the distance scale of baryonic
acoustic oscillations (BAO) and the distribution of large scale structures
(LSS). We show that a good concordance is obtained, albeit with a higher value
of the present matter abundance than in the standard model.Comment: Presented at "Spanish Relativity Meeting" (ERE2012) and "Relativity
  and Gravitation: 100 years after Einstein in Prague" (Prague, 2012
Regular and Chaotic Motion in General Relativity: The Case of a Massive
  Magnetic Dipole

Circular motion of particles, dust grains and fluids in the vicinity of
compact objects has been investigated as a model for accretion of gaseous and
dusty environment. Here we further discuss, within the framework of general
relativity, figures of equilibrium of matter under the influence of combined
gravitational and large-scale magnetic fields, assuming that the accreted
material acquires a small electric charge due to interplay of plasma processes
and photoionization. In particular, we employ an exact solution describing the
massive magnetic dipole and we identify the regions of stable motion. We also
investigate situations when the particle dynamics exhibits the onset of chaos.
In order to characterize the measure of chaoticness we employ techniques of
Poincar\'e surfaces of section and of recurrence plots.Comment: 11 pages, 6 figures, published in the proceedings of the conference
  "Relativity and Gravitation: 100 Years after Einstein in Prague" (25. - 29.
  6. 2012, Prague
The fitting problem in a lattice Universe

We present a regular cubic lattice solution to Einstein field equations
that is exact at second order in a small parameter. We show that this solution
is kinematically equivalent to the Friedmann-Lemaˆıtre-Robertson-Walker (FLRW)
solution with the same averaged energy density. This allows us to discuss the fitting
problem in that framework: are observables along the past lightcone of observers
equivalent to those in the analogue FLRW model obtained by smoothing spatially
the distribution of matter? We find a criterion on the compacity of the objects that
must be satisfied in order for the answer to this question to be positive and given
by perturbative arguments. If this criterion is not met, the answer to this question
must be addressed fully non perturbatively along the past lightcone, even though the
spacetime geometry can be described perturbatively.
Effect of magnetic fields on equatorial circular orbits in Kerr
  spacetimes

In this work we analyze the effects of an external magnetic field on charged
particles on equatorial circular orbits in a Kerr spacetime, both in the black
hole and the naked singularity cases. Understanding these phenomena is of great
importance because equatorial circular orbits are a key ingredient of simple
accretion disc models. We focus on two important magnetic field configurations:
a) a uniform magnetic field aligned with the angular momentum and b) a dipolar
magnetic field. We center our attention on the effect of these external fields
on the marginally bounded and marginally stable equatorial circular orbits
because they give information on observable quantities that could be useful to
determine whether the central object is a black hole or a naked singularity.
Using a perturbative approach we are able to give analytic results and compare
(in the black hole case) with previous results.Comment: 4 pages, 2 figures, accepted for publication in the proceedings of
  the Relativity and Gravitation, 100 Years after Einstein in Prague meeting
  held in Prague, Czech Republic during June 25 - 29, 201
Spontaneous breaking of Lorentz symmetry for canonical gravity

In the Ashtekar-Barbero formulation of canonical general relativity based on
an SU(2) connection, Lorentz covariance is a subtle issue which has been the
focus of some debate. Here we present a Lorentz covariant formulation
generalising the notion of a foliation of spacetime to a field of local
observers which specify a time direction only locally. This field spontaneously
breaks the local SO(3,1) symmetry down to a subgroup SO(3); we show that the
apparent symmetry breaking to SO(3) is not in conflict with Lorentz covariance.
We give a geometric picture of our construction as Cartan geometrodynamics and
outline further applications of the formalism of local observers, motivating
the idea that observer space, instead of spacetime, should serve as the
fundamental arena for gravitational physics.Comment: 8 pages, contribution to the proceedings of the conference
  "Relativity and Gravitation - 100 years after Einstein in Prague"; v2: added
  heading "References
Introducing Problem-Based Learning in a Joint Masters Degree: Offshoring Information Technologies

International audienceA young offshore software industry has grown up in Morocco. The University of Brest has set up a network of major software companies and Moroccan universities, providing two mobility schemes towards France. Both schemes include a final internship on the French side of global companies, with pre-employment on the Moroccan side - a successful internship being the key that opens the door to recruitment. Student heterogeneity, and student reluctance to move towards a professional attitude are important barriers to employability. Hence, we redesigned a significant proportion of our technical courses to use a problem-based learning (PBL) approach. The PBL approach is illustrated through drawing parallels with the production of a TV series. Three aspects of the approach are presented: (i) set-up of the studio in which sessions are run, i.e. a real software project, its work products and its software development environment; (ii) pre-production tasks including the screenwriting of problem-based learning scenarios and the procurement of input artefacts; and (iii) acting, i.e. students' interpretation of characters (roles) and teacher direction
Requirements based estimation approach for system engineering projects

In this paper the requirements are used for the purpose of the estimation. Requirements are cluster according to their complexity. The new approach in the papers is based on requirements analysis. The complexity of the requirements is set and Total Requirements Points Value (TRP) is calculated. The Total Requirements Points are modified by the technical and environmental factors, which described the problem domain and the development team experiences. The Total Requirements point can be used as a coefficient for the system size. According this approach system-engineering project can be compared and priced
Process of transformation, Storage and data analysis for data mart enlargement

Creation of the information system is the complex and long process but it is only the first step in its existence. Most of information systems go through a certain development during its life cycle. Very often the users have defined the requests for the enlargement of the functionality and the volume of the displayed data. The process of the transformation, storage and analysis for data mart enlargement based on the users’ requests; concretely the data mart of the personal transport is presented in the paper. The expressions from the field of the Business Intelligence and the systems used for gaining data, data analysis or creation of forms and reports are explained
Template-based ontology population for Smart Environments configuration

Smart Environment is one of several domains in which Semantic Web technologies are applied nowadays. Ontologies, in particular, are used as core modeling languages for representing devices, systems and environments. Developing such ontologies, that typically involve several device descriptions (individuals) and related information, i.e., individuals of classes contributing to the device model, is often done by a manual, time consuming, and error-prone approach. Flexible and semi-automatic tools are therefore needed to enhance ontology population and to enable end-users to fruitfully configure their Smart Environments without the intervention of an ontology expert. This paper presents a template based approach, which increases accuracy, ease of use, and time-effectiveness of the ontology population process by reducing the amount of user-given information of about an order of magnitude, with respect to the fully manual approach. User-required information only pertains device features (e.g., name, location, etc.) and never implies knowledge of Semantic Web technologies, thus enabling end-user configuration of smart homes and buildings. Experimental results with a prototypical implementation confirm the viability of the approach on a real-world use cas
A light-weight framework for bridge-building from desktop to cloud

A significant trend in science research for at least the past decade has been the increasing uptake of computational techniques (modelling) for insilico experimentation, which is trickling down from the grand challenges that require capability computing to smaller-scale problems suited to capacity computing. Such virtual experiments also establish an opportunity for collaboration at a distance. At the same time, the development of web service and cloud technology, is providing a potential platform to support these activities. The problem on which we focus is the technical hurdles for users without detailed knowledge of such mechanisms - in a word, 'accessibility' - specifically: (i) the heavy weight and diversity of infrastructures that inhibits shareability and collaboration between services, (ii) the relatively complicated processes associated with deployment and management of web services for non-disciplinary specialists, and (iii) the relative technical difficulty in packaging the legacy software that encapsulates key discipline knowledge for web-service environments. In this paper, we describe a light-weight framework based on cloud and REST to address the above issues. The framework provides a model that allows users to deploy REST services from the desktop on to computing infrastructure without modification or recompilation, utilizing legacy applications developed for the command-line. A behind-the-scenes facility provides asynchronous distributed staging of data (built directly on HTTP and REST). We describe the framework, comprising the service factory, data staging services and the desktop file manager overlay for service deployment, and present experimental results regarding: (i) the improvement in turnaround time from the data staging service, and (ii) the evaluation of usefulness and usability of the framework through case studies in image processing and in multi-disciplinary optimization
Generalized differential privacy: regions of priors that admit robust optimal mechanisms

International audienceDifferential privacy is a notion of privacy that was initially designed for statistical databases, and has been recently extended to a more general class of domains. Both differential privacy and its generalized version can be achieved by adding random noise to the reported data. Thus, privacy is obtained at the cost of reducing the data's accuracy, and therefore their utility. In this paper we consider the problem of identifying optimal mechanisms for gen- eralized differential privacy, i.e. mechanisms that maximize the utility for a given level of privacy. The utility usually depends on a prior distribution of the data, and naturally it would be desirable to design mechanisms that are universally optimal, i.e., optimal for all priors. However it is already known that such mechanisms do not exist in general. We then characterize maximal classes of priors for which a mechanism which is optimal for all the priors of the class does exist. We show that such classes can be defined as convex polytopes in the priors space. As an application, we consider the problem of privacy that arises when using, for instance, location-based services, and we show how to define mechanisms that maximize the quality of service while preserving the desired level of geo- indistinguishability
Decoder Hardware Architecture for HEVC

This chapter provides an overview of the design challenges faced in the implementation of hardware HEVC decoders. These challenges can be attributed to the larger and diverse coding block sizes and transform sizes, the larger interpolation filter for motion compensation, the increased number of steps in intra prediction and the introduction of a new in-loop filter. Several solutions to address these implementation challenges are discussed. As a reference, results for an HEVC decoder test chip are also presented.Texas Instruments Incorporate
Entropy Coding in HEVC

Context-Based Adaptive Binary Arithmetic Coding (CABAC) is a method of entropy coding first introduced in H.264/AVC and now used in the latest High Efficiency Video Coding (HEVC) standard. While it provides high coding efficiency, the data dependencies in H.264/AVC CABAC make it challenging to parallelize and thus limit its throughput. Accordingly, during the standardization of entropy coding for HEVC, both aspects of coding efficiency and throughput were considered. This chapter describes the functionality and design methodology behind CABAC entropy coding in HEVC
Multiscale Partition of Unity

We introduce a new Partition of Unity Method for the numerical homogenization
of elliptic partial differential equations with arbitrarily rough coefficients.
We do not restrict to a particular ansatz space or the existence of a finite
element mesh. The method modifies a given partition of unity such that optimal
convergence is achieved independent of oscillation or discontinuities of the
diffusion coefficient. The modification is based on an orthogonal decomposition
of the solution space while preserving the partition of unity property. This
precomputation involves the solution of independent problems on local
subdomains of selectable size. We deduce quantitative error estimates for the
method that account for the chosen amount of localization. Numerical
experiments illustrate the high approximation properties even for 'cheap'
parameter choices.Comment: Proceedings for Seventh International Workshop on Meshfree Methods
  for Partial Differential Equations, 18 pages, 3 figure
Meshfree Finite Differences for Vector Poisson and Pressure Poisson Equations with Electric Boundary Conditions

We demonstrate how meshfree finite difference methods can be applied to solve vector Poisson problems with electric boundary conditions. In these, the tangential velocity and the incompressibility of the vector field are prescribed at the boundary. Even on irregular domains with only convex corners, canonical nodalbased finite elements may converge to the wrong solution due to a version of the Babuška paradox. In turn, straightforward meshfree finite differences converge to the true solution, and even high-order accuracy can be achieved in a simple fashion. The methodology is then extended to a specific pressure Poisson equation reformulation of the Navier-Stokes equations that possesses the same type of boundary conditions. The resulting numerical approach is second order accurate and allows for a simple switching between an explicit and implicit treatment of the viscosity terms. Keywords: Meshfree Finite-differences; Navier-Stokes; Incompressible; Vector Poisson equation; Pressure Poisson equation; Reformulation; Manufactured solution; High-orderNational Science Foundation (U.S.) (Grant DMS–1318942
An Ontology-Enabled Approach for Modelling Business Processes

International audienceColoured Petri Nets (CPNs) have formal semantics and can describe any type of workflow system, behavioral and syntax wise simultaneously. They are widely studied and successfully applied in modelling of workflows and workflow systems. There is an inherent problem regarding business processes modelled with CPNs sharing and subsequently their reuse need to be considered. The Semantic Web technologies, such as ontologies, with their characteristics demonstrate that they can play an important role in this scenario. In this paper, we propose an ontological approach for representing business models in a meta-knowledge base. Firstly, the CPN ontology is defined to represent CPNs with OWL DL. Secondly, we introduce four basic types of manipulation operations on process models used to develop and modify business workflow patterns. To the best of our knowledge, representing business process definitions and business workflow patterns as knowledge based upon ontologies is a novel approach
Real-Time Hand Shape Classification

The problem of hand shape classification is challenging since a hand is
characterized by a large number of degrees of freedom. Numerous shape
descriptors have been proposed and applied over the years to estimate and
classify hand poses in reasonable time. In this paper we discuss our parallel
framework for real-time hand shape classification applicable in real-time
applications. We show how the number of gallery images influences the
classification accuracy and execution time of the parallel algorithm. We
present the speedup and efficiency analyses that prove the efficacy of the
parallel implementation. Noteworthy, different methods can be used at each step
of our parallel framework. Here, we combine the shape contexts with the
appearance-based techniques to enhance the robustness of the algorithm and to
increase the classification score. An extensive experimental study proves the
superiority of the proposed approach over existing state-of-the-art methods.Comment: 11 page
Xml warehouse modelling and querying

Integrating XML documents in data warehouse is a major issue for decisional data processing and business intelligence. Indeed this type of data is increasingly being used in organisations’ information system. But the current warehousing systems do not manage documents as they do for extracted data from relational databases. We have therefore developed a multidimensional model based on the Unified Modeling Language (UML), to describe an XML Document Warehouse (XDW). The warehouse diagram obtained is a Star schema ( StarCD) which fact represents the documents class to be analyzed, and the dimensions correspond to analysis criteria extracted from the structure of the documents. The standard XQuery language can express queries on XML documents, but it is not suitable for analyzing a warehouse as its syntax is too complex for a non IT specialist. This paper presents a new language aimed at decision-makers and allows applying OLAP queries on a XDW described by a StarCD