Characteristics of thermalization of boost-invariant plasma from holography
Heller, M.P.; Janik, R.A.; Witaszczyk, P.
2012-01-01
We report on the approach toward the hydrodynamic regime of boost-invariant N=4 super Yang-Mills plasma at strong coupling starting from various far-from-equilibrium states at τ=0. The results are obtained through a numerical solution of Einstein’s equations for the dual geometries, as described in
Consistent Holographic Description of Boost-Invariant Plasma
Heller, Michal P.; Surówka, Piotr; Loganayagam, R.; Spaliński, Michał; Vázquez, Samuel E.
2009-01-01
Prior attempts to construct the gravity dual of boost-invariant flow of N=4 supersymmetric Yang-Mills gauge theory plasma suffered from apparent curvature singularities in the late-time expansion. This Letter shows how these problems can be resolved by a different choice of expansion parameter. The calculations presented correctly reproduce the plasma energy-momentum tensor within the framework of second-order viscous hydrodynamics.
Consistent holographic description of boost-invariant plasma.
Heller, Michal P; Surówka, Piotr; Loganayagam, R; Spaliński, Michał; Vázquez, Samuel E
2009-01-30
Prior attempts to construct the gravity dual of boost-invariant flow of N=4 supersymmetric Yang-Mills gauge theory plasma suffered from apparent curvature singularities in the late-time expansion. This Letter shows how these problems can be resolved by a different choice of expansion parameter. The calculations presented correctly reproduce the plasma energy-momentum tensor within the framework of second-order viscous hydrodynamics.
Characteristics of Thermalization of Boost-Invariant Plasma from Holography
Heller, Michal P.; Janik, Romuald A.; Witaszczyk, Przemysław
2012-05-01
We report on the approach toward the hydrodynamic regime of boost-invariant N=4 super Yang-Mills plasma at strong coupling starting from various far-from-equilibrium states at τ=0. The results are obtained through a numerical solution of Einstein’s equations for the dual geometries, as described in detail in the companion article [M. P. Heller, R. A. Janik, and P. Witaszczyk, arXiv:1203.0755]. Despite the very rich far-from-equilibrium evolution, we find surprising regularities in the form of clear correlations between initial entropy and total produced entropy, as well as between initial entropy and the temperature at thermalization, understood as the transition to a hydrodynamic description. For 29 different initial conditions that we consider, hydrodynamics turns out to be definitely applicable for proper times larger than 0.7 in units of inverse temperature at thermalization. We observe a sizable anisotropy in the energy-momentum tensor at thermalization, which is nevertheless entirely due to hydrodynamic effects. This suggests that effective thermalization in heavy-ion collisions may occur significantly earlier than true thermalization.
Characteristics of thermalization of boost-invariant plasma from holography.
Heller, Michal P; Janik, Romuald A; Witaszczyk, Przemysław
2012-05-18
We report on the approach toward the hydrodynamic regime of boost-invariant N=4 super Yang-Mills plasma at strong coupling starting from various far-from-equilibrium states at τ=0. The results are obtained through a numerical solution of Einstein's equations for the dual geometries, as described in detail in the companion article [M. P. Heller, R. A. Janik, and P. Witaszczyk, arXiv:1203.0755]. Despite the very rich far-from-equilibrium evolution, we find surprising regularities in the form of clear correlations between initial entropy and total produced entropy, as well as between initial entropy and the temperature at thermalization, understood as the transition to a hydrodynamic description. For 29 different initial conditions that we consider, hydrodynamics turns out to be definitely applicable for proper times larger than 0.7 in units of inverse temperature at thermalization. We observe a sizable anisotropy in the energy-momentum tensor at thermalization, which is nevertheless entirely due to hydrodynamic effects. This suggests that effective thermalization in heavy-ion collisions may occur significantly earlier than true thermalization.
Directory of Open Access Journals (Sweden)
Zhengbin Pang
2009-01-01
Full Text Available We present a reconfigurable architecture model for rotation invariant multi-view face detection based on a novel two-stage boosting method. A tree-structured detector hierarchy is designed to organize multiple detector nodes identifying pose ranges of faces. We propose a boosting algorithm for training the detector nodes. The strong classifier in each detector node is composed of multiple novelly designed two-stage weak classifiers. With a shared output space of multicomponents vector, each detector node deals with the multidimensional binary classification problems. The design of the hardware architecture which fully exploits the spatial and temporal parallelism is introduced in detail. We also study the reconfiguration of the architecture for finding an appropriate tradeoff among the hardware implementation cost, the detection accuracy, and speed. Experiments on FPGA show that high accuracy and marvelous speed are achieved compared with previous related works. The execution time speedups range from 14.68 to 20.86 for images with size of 160×120 up to 800×600 when our FPGA design (98 MHz is compared with software solution on PC (Pentium 4 2.8 GHz.
Indian Academy of Sciences (India)
removed two cells of the same color. Whenever you are putting a 2 × 1 rectangle you are covering one black and one white cell. So the total number of white cells you have covered minus the total number of black cells you have covered after putting some 2 × 1 rectangles is always zero. So this difference is an invariant! You.
Local invariants in non-ideal flows of neutral fluids and two-fluid plasmas
Zhu, Jian-Zhou
2018-03-01
The main objective is the locally invariant geometric object of any (magneto-)fluid dynamics with forcing and damping (nonideal), while more attention is paid to the untouched dynamical properties of two-fluid fashion. Specifically, local structures, beyond the well-known "frozen-in" to the barotropic flows of the generalized vorticities, of the two-fluid model of plasma flows are presented. More general non-barotropic situations are also considered. A modified Euler equation [T. Tao, "Finite time blowup for Lagrangian modifications of the three-dimensional Euler equation," Ann. PDE 2, 9 (2016)] is also accordingly analyzed and remarked from the angle of view of the two-fluid model, with emphasis on the local structures. The local constraints of high-order differential forms such as helicity, among others, find simple formulation for possible practices in modeling the dynamics. Thus, the Cauchy invariants equation [N. Besse and U. Frisch, "Geometric formulation of the Cauchy invariants for incompressible Euler flow in flat and curved spaces," J. Fluid Mech. 825, 412 (2017)] may be enabled to find applications in non-ideal flows. Some formal examples are offered to demonstrate the calculations, and particularly interestingly the two-dimensional-three-component (2D3C) or the 2D passive scalar problem presents that a locally invariant Θ = 2θζ, with θ and ζ being, respectively, the scalar value of the "vertical velocity" (or the passive scalar) and the "vertical vorticity," may be used as if it were the spatial density of the globally invariant helicity, providing a Lagrangian prescription to control the latter in some situations of studying its physical effects in rapidly rotating flows (ubiquitous in atmosphere of astrophysical objects) with marked 2D3C vortical modes or in purely 2D passive scalars.
International Nuclear Information System (INIS)
J. B. Green, Jr.; N. Domingo; J. M. E. Storey; R.M. Wagner; J.S. Armfield; L. Bromberg; D. R. Cohn; A. Rabinovich; N. Alexeev
2000-01-01
It is well known that hydrogen addition to spark-ignited (SI) engines can reduce exhaust emissions and increase efficiency. Micro plasmatron fuel converters can be used for onboard generation of hydrogen-rich gas by partial oxidation of a wide range of fuels. These plasma-boosted microreformers are compact, rugged, and provide rapid response. With hydrogen supplement to the main fuel, SI engines can run very lean resulting in a large reduction in nitrogen oxides (NO x ) emissions relative to stoichiometric combustion without a catalytic converter. This paper presents experimental results from a microplasmatron fuel converter operating under variable oxygen to carbon ratios. Tests have also been carried out to evaluate the effect of the addition of a microplasmatron fuel converter generated gas in a 1995 2.3-L four-cylinder SI production engine. The tests were performed with and without hydrogen-rich gas produced by the plasma boosted fuel converter with gasoline. A one hundred fold reduction in NO x due to very lean operation was obtained under certain conditions. An advantage of onboard plasma-boosted generation of hydrogen-rich gas is that it is used only when required and can be readily turned on and off. Substantial NO x reduction should also be obtainable by heavy exhaust gas recirculation (EGR) facilitated by use of hydrogen-rich gas with stoichiometric operation
Milne boost from Galilean gauge theory
Banerjee, Rabin; Mukherjee, Pradip
2018-03-01
Physical origin of Milne boost invariance of the Newton Cartan spacetime is traced to the effect of local Galilean boosts in its metric structure, using Galilean gauge theory. Specifically, we do not require any gauge field to understand Milne boost invariance.
Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.
Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M
2015-03-27
An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19} W/ cm^{2}. Highly charged gold ions with kinetic energies up to >200 MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.
Lorentz invariance with an invariant energy scale.
Magueijo, João; Smolin, Lee
2002-05-13
We propose a modification of special relativity in which a physical energy, which may be the Planck energy, joins the speed of light as an invariant, in spite of a complete relativity of inertial frames and agreement with Einstein's theory at low energies. This is accomplished by a nonlinear modification of the action of the Lorentz group on momentum space, generated by adding a dilatation to each boost in such a way that the Planck energy remains invariant. The associated algebra has unmodified structure constants. We also discuss the resulting modifications of field theory and suggest a modification of the equivalence principle which determines how the new theory is embedded in general relativity.
Radjavi, Heydar
2003-01-01
This broad survey spans a wealth of studies on invariant subspaces, focusing on operators on separable Hilbert space. Largely self-contained, it requires only a working knowledge of measure theory, complex analysis, and elementary functional analysis. Subjects include normal operators, analytic functions of operators, shift operators, examples of invariant subspace lattices, compact operators, and the existence of invariant and hyperinvariant subspaces. Additional chapters cover certain results on von Neumann algebras, transitive operator algebras, algebras associated with invariant subspaces,
Question of Lorentz invariance in muon decay
Noordmans, J.P.; Onderwater, C. J. G.; Wilschut, H. W.; Timmermans, R. G. E.
2014-01-01
Possibilities to test the Lorentz invariance of the weak interaction in muon decay are considered. We derive the general Lorentz-violating muon-decay rate and discuss measurements of the directional and boost dependence of the Michel parameters and of the muon lifetime as function of absolute
Viscous plasma evolution from gravity using anti-de sitter/conformal-field-theory correspondence.
Janik, Romuald A
2007-01-12
We analyze the anti-de Sitter/conformal-field-theory dual geometry of an expanding boost-invariant plasma. We show that the requirement of nonsingularity of the dual geometry for leading and subasymptotic times predicts, without any further assumptions about gauge theory dynamics, hydrodynamic expansion of the plasma with viscosity coefficient exactly matching the one obtained earlier in the static case by Policastro, Son, and Starinets.
Boosting foundations and algorithms
Schapire, Robert E
2012-01-01
Boosting is an approach to machine learning based on the idea of creating a highly accurate predictor by combining many weak and inaccurate "rules of thumb." A remarkably rich theory has evolved around boosting, with connections to a range of topics, including statistics, game theory, convex optimization, and information geometry. Boosting algorithms have also enjoyed practical success in such fields as biology, vision, and speech processing. At various times in its history, boosting has been perceived as mysterious, controversial, even paradoxical.
Global Dirac bispinor entanglement under Lorentz boosts
Bittencourt, Victor A. S. V.; Bernardini, Alex E.; Blasone, Massimo
2018-03-01
The effects of Lorentz boosts on the quantum entanglement encoded by a pair of massive spin-1/2 particles are described according to the Lorentz covariant structure described by Dirac bispinors. The quantum system considered incorporates four degrees of freedom: two of them related to the bispinor intrinsic parity and the other two related to the bispinor spin projection, i.e., the Dirac particle helicity. Because of the natural multipartite structure involved, the Meyer-Wallach global measure of entanglement is preliminarily used for computing global quantum correlations, while the entanglement separately encoded by spin degrees of freedom is measured through the negativity of the reduced two-particle spin-spin state. A general framework to compute the changes on quantum entanglement induced by a boost is developed and then specialized to describe three particular antisymmetric two-particle states. According to the results obtained, two-particle spin-spin entanglement cannot be created by the action of a Lorentz boost in a spin-spin separable antisymmetric state. On the other hand, the maximal spin-spin entanglement encoded by antisymmetric superpositions is degraded by Lorentz boosts driven by high-speed frame transformations. Finally, the effects of boosts on chiral states are shown to exhibit interesting invariance properties, which can only be obtained through such a Lorentz covariant formulation of the problem.
On the construction of a geometric invariant measuring the deviation from Kerr data
Bäckdahl, Thomas; Kroon, Juan A. Valiente
2010-01-01
This article contains a detailed and rigorous proof of the construction of a geometric invariant for initial data sets for the Einstein vacuum field equations. This geometric invariant vanishes if and only if the initial data set corresponds to data for the Kerr spacetime, and thus, it characterises this type of data. The construction presented is valid for boosted and non-boosted initial data sets which are, in a sense, asymptotically Schwarzschildean. As a preliminary step to the constructi...
Mukherjee, Arindam
2015-01-01
If you are a C++ programmer who has never used Boost libraries before, this book will get you up-to-speed with using them. Whether you are developing new C++ software or maintaining existing code written using Boost libraries, this hands-on introduction will help you decide on the right library and techniques to solve your practical programming problems.
Computational invariant theory
Derksen, Harm
2015-01-01
This book is about the computational aspects of invariant theory. Of central interest is the question how the invariant ring of a given group action can be calculated. Algorithms for this purpose form the main pillars around which the book is built. There are two introductory chapters, one on Gröbner basis methods and one on the basic concepts of invariant theory, which prepare the ground for the algorithms. Then algorithms for computing invariants of finite and reductive groups are discussed. Particular emphasis lies on interrelations between structural properties of invariant rings and computational methods. Finally, the book contains a chapter on applications of invariant theory, covering fields as disparate as graph theory, coding theory, dynamical systems, and computer vision. The book is intended for postgraduate students as well as researchers in geometry, computer algebra, and, of course, invariant theory. The text is enriched with numerous explicit examples which illustrate the theory and should be ...
Mosca, Alan; Magoulas, George D
2017-01-01
This paper introduces Deep Incremental Boosting, a new technique derived from AdaBoost, specifically adapted to work with Deep Learning methods, that reduces the required training time and improves generalisation. We draw inspiration from Transfer of Learning approaches to reduce the start-up time to training each incremental Ensemble member. We show a set of experiments that outlines some preliminary results on some common Deep Learning datasets and discuss the potential improvements Deep In...
ATLAS Boosted Objects tagging performance
Ferreira de Lima, D E; The ATLAS collaboration
2014-01-01
In the session on the performance of jet substructure reconstruction and boosted object tagging. This first contribution focuses on boosted object tagging performance. Material includes the shower deconstruction CONF note (missed BOOST2013, public), the Boosted boson tagging note (ATL-PHYS-PUB-2014-004, public since April). New papers on W/Z dsicrimination or top tagging are unlikely.
Measurement invariance versus selection invariance : Is fair selection possible?
Borsboom, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M.
This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement
Morozov, Albert D; Dragunov, Timothy N; Malysheva, Olga V
1999-01-01
This book deals with the visualization and exploration of invariant sets (fractals, strange attractors, resonance structures, patterns etc.) for various kinds of nonlinear dynamical systems. The authors have created a special Windows 95 application called WInSet, which allows one to visualize the invariant sets. A WInSet installation disk is enclosed with the book.The book consists of two parts. Part I contains a description of WInSet and a list of the built-in invariant sets which can be plotted using the program. This part is intended for a wide audience with interests ranging from dynamical
Bremsstrahlung from an Equilibrating Quark-Gluon Plasma
Mustafa, Munshi G.; Mustafa, Munshi G.; Thoma, Markus H.
2000-01-01
The photon production rate from a chemically equilibrating quark-gluon plasma likely to be produced at RHIC (BNL) and LHC (CERN) energies is computed taking into account bremsstrahlung. The plasma is assumed to be in local thermal equilibrium, but with a phase space distribution that deviates from the Fermi or Bose distribution by space-time dependent factors (fugacities). The photon spectrum is obtained by integrating the photon rate over the space-time history of the plasma, adopting a boost invariant cylindrically symmetric transverse expansion of the system with different nuclear profile functions. Initial conditions obtained from a self-screened parton cascade calculation and, for comparison, from the HIJING model are used. Compared to the equilibrium case a suppression of the photon yield by one to three orders of magnitude is observed. Furthermore the photon production due to bremsstrahlung from the chemically nonequilibrated plasma dominates over the emission from Compton scattering and quark-antiquar...
McCarty, Mark F; O'Keefe, James H; DiNicolantonio, James J
2017-05-01
The results of multi-center trials of B vitamin supplementation reveal that, whereas moderately elevated homocysteine predicts increased risk for coronary disease, it does not play a mediating role in this regard. This essay proposes that interleukin-1beta can act on hepatocytes to suppress expression of the hepatocyte-specific forms of methionine adenosyltransferase; this in turn can be expected to decrease hepatic activity of cystathionine-β-synthase, leading to an increase in plasma homocysteine. It is further proposed that interleukin-1beta (IL-1β) is a true mediating risk factor for cardiovascular disease, and that elevated homocysteine predicts coronary disease because it can serve as a marker for increased IL-1β activity. Potent statin therapy may decrease IL-1β production by suppressing inflammasome activation - thereby accounting for the marked protection from cardiovascular events observed in the classic JUPITER study, in which the enrolled subjects had low-normal Low Density Lipoprotein cholesterol but elevated C-reactive protein. Copyright © 2017 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
J. Buitrago
Full Text Available In a new classical Weyl 2-spinor approach to non abelian gauge theories, starting with the U(1 gauge group in a previous work, we study now the SU(3 case corresponding to quarks (antiquarks interacting with color fields. The principal difference with the conventional approach is that particle-field interactions are not described by means of potentials but by the field strength magnitudes. Some analytical expressions showing similarities with electrodynamics are obtained. Classical equations that describe the behavior of quarks under gluon fields might be in principle applied to the quarkâgluon plasma phase existing during the first instants of the Universe.
Algorithms in invariant theory
Sturmfels, Bernd
2008-01-01
J. Kung and G.-C. Rota, in their 1984 paper, write: "Like the Arabian phoenix rising out of its ashes, the theory of invariants, pronounced dead at the turn of the century, is once again at the forefront of mathematics". The book of Sturmfels is both an easy-to-read textbook for invariant theory and a challenging research monograph that introduces a new approach to the algorithmic side of invariant theory. The Groebner bases method is the main tool by which the central problems in invariant theory become amenable to algorithmic solutions. Students will find the book an easy introduction to this "classical and new" area of mathematics. Researchers in mathematics, symbolic computation, and computer science will get access to a wealth of research ideas, hints for applications, outlines and details of algorithms, worked out examples, and research problems.
Ushenko, A. G.; Dubolazov, A. V.; Ushenko, V. A.; Ushenko, Yu. A.; Sakhnovskiy, M. Y.; Pavlyukovich, O.; Pavlyukovich, N.; Novakovskaya, O.; Gorsky, M. P.
2016-09-01
The model of Mueller-matrix description of mechanisms of optical anisotropy that typical for polycrystalline layers of the histological sections of biological tissues and fluids - optical activity, birefringence, as well as linear and circular dichroism - is suggested. Within the statistical analysis distributions quantities of linear and circular birefringence and dichroism the objective criteria of differentiation of myocardium histological sections (determining the cause of death); films of blood plasma (liver pathology); peritoneal fluid (endometriosis of tissues of women reproductive sphere); urine (kidney disease) were determined. From the point of view of probative medicine the operational characteristics (sensitivity, specificity and accuracy) of the method of Mueller-matrix reconstruction of optical anisotropy parameters were found.
International Nuclear Information System (INIS)
Tian Chou.
1991-05-01
It is important but difficult to find the invariant groups for the differential equations. We found a new invariant group for the MKdV equation. In this paper, we present a new invariance for the CDF equation. By using this invariance, we obtain some new solutions of CDF equation. (author). 5 refs
Lorentz invariance in shape dynamics
International Nuclear Information System (INIS)
Carlip, S; Gomes, Henrique
2015-01-01
Shape dynamics is a reframing of canonical general relativity in which time reparametrization invariance is ‘traded’ for a local conformal invariance. We explore the emergence of Lorentz invariance in this model in three contexts: as a maximal symmetry, an asymptotic symmetry and a local invariance. (paper)
Robust Affine Invariant Descriptors
Directory of Open Access Journals (Sweden)
Jianwei Yang
2011-01-01
Full Text Available An approach is developed for the extraction of affine invariant descriptors by cutting object into slices. Gray values associated with every pixel in each slice are summed up to construct affine invariant descriptors. As a result, these descriptors are very robust to additive noise. In order to establish slices of correspondence between an object and its affine transformed version, general contour (GC of the object is constructed by performing projection along lines with different polar angles. Consequently, affine in-variant division curves are derived. A slice is formed by points fall in the region enclosed by two adjacent division curves. To test and evaluate the proposed method, several experiments have been conducted. Experimental results show that the proposed method is very robust to noise.
Energy Technology Data Exchange (ETDEWEB)
Perez-Nadal, Guillem [Universidad de Buenos Aires, Buenos Aires (Argentina)
2017-07-15
We consider a non-relativistic free scalar field theory with a type of anisotropic scale invariance in which the number of coordinates ''scaling like time'' is generically greater than one. We propose the Cartesian product of two curved spaces, the metric of each space being parameterized by the other space, as a notion of curved background to which the theory can be extended. We study this type of geometries, and find a family of extensions of the theory to curved backgrounds in which the anisotropic scale invariance is promoted to a local, Weyl-type symmetry. (orig.)
Modular invariant gaugino condensation
Energy Technology Data Exchange (ETDEWEB)
Gaillard, M.K.
1991-05-09
The construction of effective supergravity lagrangians for gaugino condensation is reviewed and recent results are presented that are consistent with modular invariance and yield a positive definite potential of the noscale type. Possible implications for phenomenology are briefly discussed. 29 refs.
Invariant differential operators
Dobrev, Vladimir K
2016-01-01
With applications in quantum field theory, elementary particle physics and general relativity, this two-volume work studies invariance of differential operators under Lie algebras, quantum groups, superalgebras including infinite-dimensional cases, Schrödinger algebras, applications to holography. This first volume covers the general aspects of Lie algebras and group theory.
Perspective Projection Invariants,
1986-02-01
AD-AI67 793 PERSPECTIVE PROJECTION INVARIANTS(U) MASSACHUSETTS INST 1/1~ OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB VERRI ET AL , FEB 86 AI-M-832...some stability properties. On the contrary, zeros of curvature of arbitrary 3D curves do not present any simple kindi of stability. Thus zeros of
International Nuclear Information System (INIS)
Bramson, B.D.
1978-01-01
An isolated system in general relativity makes a transition between stationary states. It is shown that the spin vectors of the system, long before and long after the emission of radiation, are supertranslation invariant and, hence, independent of the choice of Minkowski observation space. (author)
Invariants of generalized Lie algebras
International Nuclear Information System (INIS)
Agrawala, V.K.
1981-01-01
Invariants and invariant multilinear forms are defined for generalized Lie algebras with arbitrary grading and commutation factor. Explicit constructions of invariants and vector operators are given by contracting invariant forms with basic elements of the generalized Lie algebra. The use of the matrix of a linear map between graded vector spaces is emphasized. With the help of this matrix, the concept of graded trace of a linear operator is introduced, which is a rich source of multilinear forms of degree zero. To illustrate the use of invariants, a characteristic identity similar to that of Green is derived and a few Racah coefficients are evaluated in terms of invariants
Polarization particle drift and quasi-particle invariants
International Nuclear Information System (INIS)
Sosenko, P.P.
1995-01-01
The second-order approximation in quasi-particle description of magnetized plasmas is studied. Reduced particle and guiding-centre velocities are derived taking account of the second-order renormalization and polarization drift modified owing to finite-Larmor-radius effects. The second-order adiabatic invariant of quasi-particle motion is found. Global adiabatic invariants for the magnetized plasma are revealed, and their possible role in energy exchange between particles and fields, nonlinear mode cascades and global plasma stability is shown. 49 refs
Distribution-Specific Agnostic Boosting
Feldman, Vitaly
2009-01-01
We consider the problem of boosting the accuracy of weak learning algorithms in the agnostic learning framework of Haussler (1992) and Kearns et al. (1992). Known algorithms for this problem (Ben-David et al., 2001; Gavinsky, 2002; Kalai et al., 2008) follow the same strategy as boosting algorithms in the PAC model: the weak learner is executed on the same target function but over different distributions on the domain. We demonstrate boosting algorithms for the agnostic learning framework tha...
Boost C++ application development cookbook
Polukhin, Antony
2013-01-01
This book follows a cookbook approach, with detailed and practical recipes that use Boost libraries.This book is great for developers new to Boost, and who are looking to improve their knowledge of Boost and see some undocumented details or tricks. It's assumed that you will have some experience in C++ already, as well being familiar with the basics of STL. A few chapters will require some previous knowledge of multithreading and networking. You are expected to have at least one good C++ compiler and compiled version of Boost (1.53.0 or later is recommended), which will be used during the exer
Gradient Boosting Machines, A Tutorial
Directory of Open Access Journals (Sweden)
Alexey eNatekin
2013-12-01
Full Text Available Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods. A theoretical information is complemented with many descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. A set of practical examples of gradient boosting applications are presented and comprehensively analyzed.
Analytic invariants of boundary links
Garoufalidis, Stavros; Levine, Jerome
2001-01-01
Using basic topology and linear algebra, we define a plethora of invariants of boundary links whose values are power series with noncommuting variables. These turn out to be useful and elementary reformulations of an invariant originally defined by M. Farber.
Continuous Integrated Invariant Inference Project
National Aeronautics and Space Administration — The proposed project will develop a new technique for invariant inference and embed this and other current invariant inference and checking techniques in an...
Status of time reversal invariance
International Nuclear Information System (INIS)
Henley, E.M.
1989-01-01
Time Reversal Invariance is introduced, and theories for its violation are reviewed. The present experimental and theoretical status of Time Reversal Invariance and tests thereof will be presented. Possible future tests will be discussed
Differential invariants in nonclassical models of hydrodynamics
Bublik, Vasily V.
2017-10-01
In this paper, differential invariants are used to construct solutions for equations of the dynamics of a viscous heat-conducting gas and the dynamics of a viscous incompressible fluid modified by nanopowder inoculators. To describe the dynamics of a viscous heat-conducting gas, we use the complete system of Navier—Stokes equations with allowance for heat fluxes. Mathematical description of the dynamics of liquid metals under high-energy external influences (laser radiation or plasma flow) includes, in addition to the Navier—Stokes system of an incompressible viscous fluid, also heat fluxes and processes of nonequilibrium crystallization of a deformable fluid. Differentially invariant solutions are a generalization of partially invariant solutions, and their active study for various models of continuous medium mechanics is just beginning. Differentially invariant solutions can also be considered as solutions with differential constraints; therefore, when developing them, the approaches and methods developed by the science schools of academicians N. N. Yanenko and A. F. Sidorov will be actively used. In the construction of partially invariant and differentially invariant solutions, there are overdetermined systems of differential equations that require a compatibility analysis. The algorithms for reducing such systems to involution in a finite number of steps are described by Cartan, Finikov, Kuranishi, and other authors. However, the difficultly foreseeable volume of intermediate calculations complicates their practical application. Therefore, the methods of computer algebra are actively used here, which largely helps in solving this difficult problem. It is proposed to use the constructed exact solutions as tests for formulas, algorithms and their software implementations when developing and creating numerical methods and computational program complexes. This combination of effective numerical methods, capable of solving a wide class of problems, with
Conformal invariance of curvature perturbation
Gong, Jinn-Ouk; Park, Wan Il; Sasaki, Misao; Song, Yong-Seon
2011-01-01
We show that in the single component situation all perturbation variables in the comoving gauge are conformally invariant to all perturbation orders. Generally we identify a special time slicing, the uniform-conformal transformation slicing, where all perturbations are again conformally invariant to all perturbation orders. We apply this result to the delta N formalism, and show its conformal invariance.
Invariant scattering convolution networks.
Bruna, Joan; Mallat, Stéphane
2013-08-01
A wavelet scattering network computes a translation invariant image representation which is stable to deformations and preserves high-frequency information for classification. It cascades wavelet transform convolutions with nonlinear modulus and averaging operators. The first network layer outputs SIFT-type descriptors, whereas the next layers provide complementary invariant information that improves classification. The mathematical analysis of wavelet scattering networks explains important properties of deep convolution networks for classification. A scattering representation of stationary processes incorporates higher order moments and can thus discriminate textures having the same Fourier power spectrum. State-of-the-art classification results are obtained for handwritten digits and texture discrimination, with a Gaussian kernel SVM and a generative PCA classifier.
Conformal invariance in supergravity
International Nuclear Information System (INIS)
Bergshoeff, E.A.
1983-01-01
In this thesis the author explains the role of conformal invariance in supergravity. He presents the complete structure of extended conformal supergravity for N <= 4. The outline of this work is as follows. In chapter 2 he briefly summarizes the essential properties of supersymmetry and supergravity and indicates the use of conformal invariance in supergravity. The idea that the introduction of additional symmetry transformations can make clear the structure of a field theory is not reserved to supergravity only. By means of some simple examples it is shown in chapter 3 how one can always introduce additional gauge transformations in a theory of massive vector fields. Moreover it is shown how the gauge invariant formulation sometimes explains the quantum mechanical properties of the theory. In chapter 4 the author defines the conformal transformations and summarizes their main properties. He explains how these conformal transformations can be used to analyse the structure of gravity. The supersymmetric extension of these results is discussed in chapter 5. Here he describes as an example how N=1 supergravity can be reformulated in a conformally-invariant way. He also shows that beyond N=1 the gauge fields of the superconformal symmetries do not constitute an off-shell field representation of extended conformal supergravity. Therefore, in chapter 6, a systematic method to construct the off-shell formulation of all extended conformal supergravity theories with N <= 4 is developed. As an example he uses this method to construct N=1 conformal supergravity. Finally, in chapter 7 N=4 conformal supergravity is discussed. (Auth.)
2010-12-02
evaluating the function ΘP (A) for any fixed A,P is equivalent to solving the so-called Quadratic Assignment Problem ( QAP ), and thus we can employ various...tractable linear programming, spectral, and SDP relaxations of QAP [40, 11, 33]. In particular we discuss recent work [14] on exploiting group...symmetry in SDP relaxations of QAP , which is useful for approximately computing elementary convex graph invariants in many interesting cases. Finally in
Czech Academy of Sciences Publication Activity Database
Flusser, Jan; Kautský, J.; Šroubek, Filip
2010-01-01
Roč. 86, č. 1 (2010), s. 72-86 ISSN 0920-5691 R&D Projects: GA MŠk 1M0572; GA ČR GA102/08/1593 Institutional research plan: CEZ:AV0Z10750506 Keywords : Implicit invariants * Orthogonal polynomials * Polynomial image deformation Subject RIV: BD - Theory of Information Impact factor: 4.930, year: 2010 http://library.utia.cas.cz/separaty/2009/ZOI/flusser-0329394.pdf
Czech Academy of Sciences Publication Activity Database
Suk, Tomáš; Flusser, Jan
2004-01-01
Roč. 26, č. 10 (2004), s. 1364-1367 ISSN 0162-8828 R&D Projects: GA ČR GA201/03/0675 Institutional research plan: CEZ:AV0Z1075907 Keywords : projective transform * moment invariants * object recognition Subject RIV: JD - Computer Applications, Robotics Impact factor: 4.352, year: 2004 http://library.utia.cas.cz/prace/20040112.pdf
Schlaffer, Matthias; Takeuchi, Michihisa; Weiler, Andreas; Wymant, Chris
2014-01-01
The inclusive Higgs production rate through gluon fusion has been measured to be in agreement with the Standard Model (SM). We show that even if the inclusive Higgs production rate is very SM-like, a precise determination of the boosted Higgs transverse momentum shape offers the opportunity to see effects of natural new physics. These measurements are generically motivated by effective field theory arguments and specifically in extensions of the SM with a natural weak scale, like composite Higgs models and natural supersymmetry. We show in detail how a measurement at high transverse momentum of $H\\to 2\\ell+\\mathbf{p}\\!\\!/_T$ via $H\\to \\tau\\tau$ and $H\\to WW^*$ could be performed and demonstrate that it offers a compelling alternative to the $t\\bar t H$ channel. We discuss the sensitivity to new physics in the most challenging scenario of an exactly SM-like inclusive Higgs cross-section.
Project BOOST implementation: lessons learned.
Williams, Mark V; Li, Jing; Hansen, Luke O; Forth, Victoria; Budnitz, Tina; Greenwald, Jeffrey L; Howell, Eric; Halasyamani, Lakshmi; Vidyarthi, Arpana; Coleman, Eric A
2014-07-01
Enhancing care coordination and reducing hospital readmissions have been a focus of multiple quality improvement (QI) initiatives. Project BOOST (Better Outcomes by Optimizing Safe Transitions) aims to enhance the discharge transition from hospital to home. Previous research indicates that QI initiatives originating externally often face difficulties gaining momentum or effecting lasting change in a hospital. We performed a qualitative evaluation of Project BOOST implementation by examining the successes and failures experienced by six pilot sites. We also evaluated the unique physician mentoring component of this program. Finally, we examined the impact of intensification of the physician mentoring model on adoption of BOOST interventions in two later Illinois cohorts (27 hospitals). Qualitative analysis of six pilot hospitals used a process of methodological triangulation and analysis of the BOOST enrollment applications, the listserv, and content from telephone interviews. Evaluation of BOOST implementation at Illinois hospitals occurred via mid-year and year-end surveys. The identified common barriers included inadequate understanding of the current discharge process, insufficient administrative support, lack of protected time or dedicated resources, and lack of frontline staff buy-in. Facilitators of implementation included the mentor, a small beginning, teamwork, and proactive engagement of the patient. Notably, hospitals viewed their mentors as essential facilitators of change. Sites consistently commented that the individualized mentoring was extremely helpful and provided significant accountability and stimulated creativity. In the Illinois cohorts, the improved mentoring model showed more complete implementation of BOOST interventions. The implementation of Project BOOST was well received by hospitals, although sites faced substantial barriers consistent with other QI research reports. The unique mentorship element of Project BOOST proved extremely
AveBoost2: Boosting for Noisy Data
Oza, Nikunj C.
2004-01-01
AdaBoost is a well-known ensemble learning algorithm that constructs its constituent or base models in sequence. A key step in AdaBoost is constructing a distribution over the training examples to create each base model. This distribution, represented as a vector, is constructed to be orthogonal to the vector of mistakes made by the pre- vious base model in the sequence. The idea is to make the next base model's errors uncorrelated with those of the previous model. In previous work, we developed an algorithm, AveBoost, that constructed distributions orthogonal to the mistake vectors of all the previous models, and then averaged them to create the next base model s distribution. Our experiments demonstrated the superior accuracy of our approach. In this paper, we slightly revise our algorithm to allow us to obtain non-trivial theoretical results: bounds on the training error and generalization error (difference between training and test error). Our averaging process has a regularizing effect which, as expected, leads us to a worse training error bound for our algorithm than for AdaBoost but a superior generalization error bound. For this paper, we experimented with the data that we used in both as originally supplied and with added label noise-a small fraction of the data has its original label changed. Noisy data are notoriously difficult for AdaBoost to learn. Our algorithm's performance improvement over AdaBoost is even greater on the noisy data than the original data.
Permutationally invariant state reconstruction
DEFF Research Database (Denmark)
Moroder, Tobias; Hyllus, Philipp; Tóth, Géza
2012-01-01
Feasible tomography schemes for large particle numbers must possess, besides an appropriate data acquisition protocol, an efficient way to reconstruct the density operator from the observed finite data set. Since state reconstruction typically requires the solution of a nonlinear large-scale opti......Feasible tomography schemes for large particle numbers must possess, besides an appropriate data acquisition protocol, an efficient way to reconstruct the density operator from the observed finite data set. Since state reconstruction typically requires the solution of a nonlinear large......-scale optimization problem, this is a major challenge in the design of scalable tomography schemes. Here we present an efficient state reconstruction scheme for permutationally invariant quantum state tomography. It works for all common state-of-the-art reconstruction principles, including, in particular, maximum...... likelihood and least squares methods, which are the preferred choices in today's experiments. This high efficiency is achieved by greatly reducing the dimensionality of the problem employing a particular representation of permutationally invariant states known from spin coupling combined with convex...
Viability, invariance and applications
Carja, Ovidiu; Vrabie, Ioan I
2007-01-01
The book is an almost self-contained presentation of the most important concepts and results in viability and invariance. The viability of a set K with respect to a given function (or multi-function) F, defined on it, describes the property that, for each initial data in K, the differential equation (or inclusion) driven by that function or multi-function) to have at least one solution. The invariance of a set K with respect to a function (or multi-function) F, defined on a larger set D, is that property which says that each solution of the differential equation (or inclusion) driven by F and issuing in K remains in K, at least for a short time.The book includes the most important necessary and sufficient conditions for viability starting with Nagumo's Viability Theorem for ordinary differential equations with continuous right-hand sides and continuing with the corresponding extensions either to differential inclusions or to semilinear or even fully nonlinear evolution equations, systems and inclusions. In th...
Invariants in probabilistic reasoning.
Costello, Fintan; Watts, Paul
2018-02-01
Recent research has identified three invariants or identities that appear to hold in people's probabilistic reasoning: the QQ identity, the addition law identity, and the Bayes rule identity (Costello and Watts, 2014, 2016a, Fisher and Wolfe, 2014, Wang and Busemeyer, 2013, Wang et al., 2014). Each of these identities represent specific agreement with the requirements of normative probability theory; strikingly, these identities seem to hold in people's judgements despite the presence of strong and systematic biases against the requirements of normative probability theory in those very same judgements. These results suggest that the systematic biases seen in people's probabilistic reasoning follow mathematical rules: for these particular identities, these rules cause an overall cancellation of biases and so produce agreement with normative requirements. We assess two competing mathematical models of probabilistic reasoning (the 'probability theory plus noise' model and the 'quantum probability' model) in terms of their ability to account for this pattern of systematic biases and invariant identities. Copyright © 2017 Elsevier Inc. All rights reserved.
Stable pair invariants of surfaces and Seiberg-Witten invariants
Kool, M.
2016-01-01
The moduli space of stable pairs on a local surface X = KS is in general non-compact. The action of C ∗ on the fibres of X induces an action on the moduli space and the stable pair invariants of X are defined by the virtual localization formula. We study the contribution to these invariants of
Wulan, Hasi
2017-01-01
This monograph summarizes the recent major achievements in Möbius invariant QK spaces. First introduced by Hasi Wulan and his collaborators, the theory of QK spaces has developed immensely in the last two decades, and the topics covered in this book will be helpful to graduate students and new researchers interested in the field. Featuring a wide range of subjects, including an overview of QK spaces, QK-Teichmüller spaces, K-Carleson measures and analysis of weight functions, this book serves as an important resource for analysts interested in this area of complex analysis. Notes, numerous exercises, and a comprehensive up-to-date bibliography provide an accessible entry to anyone with a standard graduate background in real and complex analysis.
International Nuclear Information System (INIS)
Habegger, N.; Thompson, G.
1999-11-01
Let Z LMO be the 3-manifold invariant of [LMO]. It is shown that Z LMO (M) = 1, if the first Betti number of M, b 1 (M), is greater than 3. If b 1 (M) = 3, then Z LMO (M) is completely determined by the cohomology ring of M. A relation of Z LMO with the Rozansky-Witten invariants Z X RW [M] is established at a physical level of rigour. We show that Z X RW [M] satisfies appropriate connected sum properties suggesting that the generalized Casson invariant ought to be computable from the LMO invariant. (author)
On the generalized Casson invariant
International Nuclear Information System (INIS)
Thompson, G.
1998-11-01
The path integral generalization of the Casson invariant as developed by Rozansky and Witten is investigated. The path integral for various three manifolds is explicitly evaluated. A new class of topological observables are introduced that may allow for more effective invariants. Finally it is shown how the dimensional reduction of these theories correspond to a generalization of the topological B sigma model. (author)
Hidden scale invariance of metals
DEFF Research Database (Denmark)
Hummel, Felix; Kresse, Georg; Dyre, Jeppe C.
2015-01-01
Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between the thermal fluctuations of the virial and the potential energy in the isochoric ensemble. This demonstrates a general “hidden” scale invariance...... of metals making the condensed part of the thermodynamic phase diagram effectively one dimensional with respect to structure and dynamics. DFT computed density scaling exponents, related to the Grüneisen parameter, are in good agreement with experimental values for the 16 elements where reliable data were...... available. Hidden scale invariance is demonstrated in detail for magnesium by showing invariance of structure and dynamics. Computed melting curves of period three metals follow curves with invariance (isomorphs). The experimental structure factor of magnesium is predicted by assuming scale invariant...
Physical Invariants of Intelligence
Zak, Michail
2010-01-01
A program of research is dedicated to development of a mathematical formalism that could provide, among other things, means by which living systems could be distinguished from non-living ones. A major issue that arises in this research is the following question: What invariants of mathematical models of the physics of systems are (1) characteristic of the behaviors of intelligent living systems and (2) do not depend on specific features of material compositions heretofore considered to be characteristic of life? This research at earlier stages has been reported, albeit from different perspectives, in numerous previous NASA Tech Briefs articles. To recapitulate: One of the main underlying ideas is to extend the application of physical first principles to the behaviors of living systems. Mathematical models of motor dynamics are used to simulate the observable physical behaviors of systems or objects of interest, and models of mental dynamics are used to represent the evolution of the corresponding knowledge bases. For a given system, the knowledge base is modeled in the form of probability distributions and the mental dynamics is represented by models of the evolution of the probability densities or, equivalently, models of flows of information. At the time of reporting the information for this article, the focus of this research was upon the following aspects of the formalism: Intelligence is considered to be a means by which a living system preserves itself and improves its ability to survive and is further considered to manifest itself in feedback from the mental dynamics to the motor dynamics. Because of the feedback from the mental dynamics, the motor dynamics attains quantum-like properties: The trajectory of the physical aspect of the system in the space of dynamical variables splits into a family of different trajectories, and each of those trajectories can be chosen with a probability prescribed by the mental dynamics. From a slightly different perspective
Boosting jet power in black hole spacetimes.
Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis
2011-08-02
The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.
Boosted top: experimental tools overview
Usai, Emanuele
2015-01-01
An overview of tools and methods for the reconstruction of high-boost top quark decays at the LHC is given in this report. The focus is on hadronic decays, in particular an overview of the current status of top quark taggers in physics analyses is presented. The most widely used jet substructure techniques, normally used in combination with top quark taggers, are reviewed. Special techniques to treat pileup in large cone jets are described, along with a comparison of the performance of several boosted top quark reconstruction techniques.
SemiBoost: boosting for semi-supervised learning.
Mallapragada, Pavan Kumar; Jin, Rong; Jain, Anil K; Liu, Yi
2009-11-01
Semi-supervised learning has attracted a significant amount of attention in pattern recognition and machine learning. Most previous studies have focused on designing special algorithms to effectively exploit the unlabeled data in conjunction with labeled data. Our goal is to improve the classification accuracy of any given supervised learning algorithm by using the available unlabeled examples. We call this as the Semi-supervised improvement problem, to distinguish the proposed approach from the existing approaches. We design a metasemi-supervised learning algorithm that wraps around the underlying supervised algorithm and improves its performance using unlabeled data. This problem is particularly important when we need to train a supervised learning algorithm with a limited number of labeled examples and a multitude of unlabeled examples. We present a boosting framework for semi-supervised learning, termed as SemiBoost. The key advantages of the proposed semi-supervised learning approach are: 1) performance improvement of any supervised learning algorithm with a multitude of unlabeled data, 2) efficient computation by the iterative boosting algorithm, and 3) exploiting both manifold and cluster assumption in training classification models. An empirical study on 16 different data sets and text categorization demonstrates that the proposed framework improves the performance of several commonly used supervised learning algorithms, given a large number of unlabeled examples. We also show that the performance of the proposed algorithm, SemiBoost, is comparable to the state-of-the-art semi-supervised learning algorithms.
Invariant and semi-invariant probabilistic normed spaces
Energy Technology Data Exchange (ETDEWEB)
Ghaemi, M.B. [School of Mathematics Iran, University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)], E-mail: mghaemi@iust.ac.ir; Lafuerza-Guillen, B. [Departamento de Estadistica y Matematica Aplicada, Universidad de Almeria, Almeria E-04120 (Spain)], E-mail: blafuerz@ual.es; Saiedinezhad, S. [School of Mathematics Iran, University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)], E-mail: ssaiedinezhad@yahoo.com
2009-10-15
Probabilistic metric spaces were introduced by Karl Menger. Alsina, Schweizer and Sklar gave a general definition of probabilistic normed space based on the definition of Menger . We introduce the concept of semi-invariance among the PN spaces. In this paper we will find a sufficient condition for some PN spaces to be semi-invariant. We will show that PN spaces are normal spaces. Urysohn's lemma, and Tietze extension theorem for them are proved.
Boost.Asio C++ network programming
Torjo, John
2013-01-01
What you want is an easy level of abstraction, which is just what this book provides in conjunction with Boost.Asio. Switching to Boost.Asio is just a few extra #include directives away, with the help of this practical and engaging guide.This book is great for developers that need to do network programming, who don't want to delve into the complicated issues of a raw networking API. You should be familiar with core Boost concepts, such as smart pointers and shared_from_this, resource classes (noncopyable), functors and boost::bind, boost mutexes, and the boost date/time library. Readers should
Q-Boosted Optomechanical Resonators
2015-11-18
proposing team in 2004 [6], and apparently copied now by some in the optomechanical world, who seem to be calling it a spoke-supported toroid . Beyond merely...FA9550-10-1-0293 “Q-Boosted Optomechanical Resonators” CTN 9/18/15 24 [20] D. Armani, T. Kippenberg, S. Spillane and K. Vahala, "Ultra-high-Q toroid
Berlo, L.A.H.M.
2012-01-01
Onlangs sloot TNO een samenwerkingsovereenkomst met brancheorganisaties in de bouwkolom waaromder Bouwend Nederland en BNA. Doel van de overeenkomst: een BIM-boost in Nederland bewerkstelligen. Een gesprek met Leon van Berlo van TNO over deze en andere BIM-actualiteiten
The invariant theory of matrices
Concini, Corrado De
2017-01-01
This book gives a unified, complete, and self-contained exposition of the main algebraic theorems of invariant theory for matrices in a characteristic free approach. More precisely, it contains the description of polynomial functions in several variables on the set of m\\times m matrices with coefficients in an infinite field or even the ring of integers, invariant under simultaneous conjugation. Following Hermann Weyl's classical approach, the ring of invariants is described by formulating and proving the first fundamental theorem that describes a set of generators in the ring of invariants, and the second fundamental theorem that describes relations between these generators. The authors study both the case of matrices over a field of characteristic 0 and the case of matrices over a field of positive characteristic. While the case of characteristic 0 can be treated following a classical approach, the case of positive characteristic (developed by Donkin and Zubkov) is much harder. A presentation of this case...
On the Construction of a Geometric Invariant Measuring the Deviation from Kerr Data
Bäckdahl, Thomas; Valiente Kroon, Juan A.
2010-11-01
This article contains a detailed and rigorous proof of the construction of a geometric invariant for initial data sets for the Einstein vacuum field equations. This geometric invariant vanishes if and only if the initial data set corresponds to data for the Kerr spacetime, and thus, it characterises this type of data. The construction presented is valid for boosted and non-boosted initial data sets which are, in a sense, asymptotically Schwarzschildean. As a preliminary step to the construction of the geometric invariant, an analysis of a characterisation of the Kerr spacetime in terms of Killing spinors is carried out. A space spinor split of the (spacetime) Killing spinor equation is performed, to obtain a set of three conditions ensuring the existence of a Killing spinor of the development of the initial data set. In order to construct the geometric invariant, we introduce the notion of approximate Killing spinors. These spinors are symmetric valence 2 spinors intrinsic to the initial hypersurface and satisfy a certain second order elliptic equation ---the approximate Killing spinor equation. This equation arises as the Euler-Lagrange equation of a non-negative integral functional. This functional constitutes part of our geometric invariant ---however, the whole functional does not come from a variational principle. The asymptotic behaviour of solutions to the approximate Killing spinor equation is studied and an existence theorem is presented.
Modern Tests of Lorentz Invariance
Directory of Open Access Journals (Sweden)
Mattingly David
2005-09-01
Full Text Available Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.
CPT invariance in classical electrodynamics
Kaplan, Aaron D.; Tsankov, Tsvetelin D.
2017-11-01
The transformation properties of classical electrodynamic variables under charge conjugation C, parity reversal P, and time inversion T are considered both for standard and atypical assumptions for the nature of charge. We have shown that four distinct behaviours of charge under space and time inversion are consistent with the invariance of Maxwell’s equations under CPT and P. No prior knowledge of CPT invariance is assumed and the material is accessible to undergraduate students.
Invariant measures for Chebyshev maps
Directory of Open Access Journals (Sweden)
Abraham Boyarsky
2001-01-01
Full Text Available Let Tλ(x=cos(λarccosx, −1≤x≤1, where λ>1 is not an integer. For a certain set of λ's which are irrational, the density of the unique absolutely continuous measure invariant under Tλ is determined exactly. This is accomplished by showing that Tλ is differentially conjugate to a piecewise linear Markov map whose unique invariant density can be computed as the unique left eigenvector of a matrix.
Invariant Bayesian estimation on manifolds
Jermyn, Ian H.
2005-01-01
A frequent and well-founded criticism of the maximum a posteriori (MAP) and minimum mean squared error (MMSE) estimates of a continuous parameter \\gamma taking values in a differentiable manifold \\Gamma is that they are not invariant to arbitrary ``reparameterizations'' of \\Gamma. This paper clarifies the issues surrounding this problem, by pointing out the difference between coordinate invariance, which is a sine qua non for a mathematically well-defined problem, and diffeomorphism invarianc...
Object recognition by implicit invariants
Czech Academy of Sciences Publication Activity Database
Flusser, Jan; Kautsky, J.; Šroubek, Filip
2007-01-01
Roč. 2007, č. 4673 (2007), s. 856-863 ISSN 0302-9743. [Computer Analysis of Images and Patterns. Vienna, 27.08.2007-29.08.2007] R&D Projects: GA MŠk 1M0572 Institutional research plan: CEZ:AV0Z10750506 Keywords : Invariants * implicit invariants * moments * orthogonal polynomials * nonlinear object deformation Subject RIV: JD - Computer Applications, Robotics Impact factor: 0.402, year: 2005 http://staff.utia.cas.cz/sroubekf/papers/CAIP_07.pdf
Classification of simple current invariants
Gato-Rivera, Beatriz
1992-01-01
We summarize recent work on the classification of modular invariant partition functions that can be obtained with simple currents in theories with a center (Z_p)^k with p prime. New empirical results for other centers are also presented. Our observation that the total number of invariants is monodromy-independent for (Z_p)^k appears to be true in general as well. (Talk presented in the parallel session on string theory of the Lepton-Photon/EPS Conference, Geneva, 1991.)
ATLAS measurements of boosted object production
Arguin, Jean-Francois; The ATLAS collaboration
2015-01-01
This talk reviews ATLAS Standard Model measurements performed with boosted objects, i.e. boosted top quarks and W and Z bosons, which decay hadronically and are reconstructed as a single large radius jet.
Invariant Matsumoto metrics on homogeneous spaces
Salimi Moghaddam, H.R.
2014-01-01
In this paper we consider invariant Matsumoto metrics which are induced by invariant Riemannian metrics and invariant vector fields on homogeneous spaces, and then we give the flag curvature formula of them. Also we study the special cases of naturally reductive spaces and bi-invariant metrics. We end the article by giving some examples of geodesically complete Matsumoto spaces.
ada: An R Package for Stochastic Boosting
Directory of Open Access Journals (Sweden)
Mark Culp
2006-09-01
Full Text Available Boosting is an iterative algorithm that combines simple classification rules with ‘mediocre’ performance in terms of misclassification error rate to produce a highly accurate classification rule. Stochastic gradient boosting provides an enhancement which incorporates a random mechanism at each boosting step showing an improvement in performance and speed in generating the ensemble. ada is an R package that implements three popular variants of boosting, together with a version of stochastic gradient boosting. In addition, useful plots for data analytic purposes are provided along with an extension to the multi-class case. The algorithms are illustrated with synthetic and real data sets.
ada: An R Package for Stochastic Boosting
Directory of Open Access Journals (Sweden)
Mark Culp
2006-09-01
Full Text Available Boosting is an iterative algorithm that combines simple classification rules with "mediocre" performance in terms of misclassification error rate to produce a highly accurate classification rule. Stochastic gradient boosting provides an enhancement which incorporates a random mechanism at each boosting step showing an improvement in performance and speed in generating the ensemble. ada is an R package that implements three popular variants of boosting, together with a version of stochastic gradient boosting. In addition, useful plots for data analytic purposes are provided along with an extension to the multi-class case. The algorithms are illustrated with synthetic and real data sets.
Energy Invariance in Capillary Systems
Ruiz-Gutiérrez, Élfego; Guan, Jian H.; Xu, Ben; McHale, Glen; Wells, Gary G.; Ledesma-Aguilar, Rodrigo
2017-05-01
We demonstrate the continuous translational invariance of the energy of a capillary surface in contact with reconfigurable solid boundaries. We present a theoretical approach to find the energy-invariant equilibria of spherical capillary surfaces in contact with solid boundaries of arbitrary shape and examine the implications of dynamic frictional forces upon a reconfiguration of the boundaries. Experimentally, we realize our ideas by manipulating the position of a droplet in a wedge geometry using lubricant-impregnated solid surfaces, which eliminate the contact-angle hysteresis and provide a test bed for quantifying dissipative losses out of equilibrium. Our experiments show that dissipative energy losses for an otherwise energy-invariant reconfiguration are relatively small, provided that the actuation time scale is longer than the typical relaxation time scale of the capillary surface. We discuss the wider applicability of our ideas as a pathway for liquid manipulation at no potential energy cost in low-pinning, low-friction situations.
Invariants of triangular Lie algebras
International Nuclear Information System (INIS)
Boyko, Vyacheslav; Patera, Jiri; Popovych, Roman
2007-01-01
Triangular Lie algebras are the Lie algebras which can be faithfully represented by triangular matrices of any finite size over the real/complex number field. In the paper invariants ('generalized Casimir operators') are found for three classes of Lie algebras, namely those which are either strictly or non-strictly triangular, and for so-called special upper triangular Lie algebras. Algebraic algorithm of Boyko et al (2006 J. Phys. A: Math. Gen.39 5749 (Preprint math-ph/0602046)), developed further in Boyko et al (2007 J. Phys. A: Math. Theor.40 113 (Preprint math-ph/0606045)), is used to determine the invariants. A conjecture of Tremblay and Winternitz (2001 J. Phys. A: Math. Gen.34 9085), concerning the number of independent invariants and their form, is corroborated
Dark coupling and gauge invariance
International Nuclear Information System (INIS)
Gavela, M.B.; Honorez, L. Lopez; Mena, O.; Rigolin, S.
2010-01-01
We study a coupled dark energy-dark matter model in which the energy-momentum exchange is proportional to the Hubble expansion rate. The inclusion of its perturbation is required by gauge invariance. We derive the linear perturbation equations for the gauge invariant energy density contrast and velocity of the coupled fluids, and we determine the initial conditions. The latter turn out to be adiabatic for dark energy, when assuming adiabatic initial conditions for all the standard fluids. We perform a full Monte Carlo Markov Chain likelihood analysis of the model, using WMAP 7-year data
Numeric invariants from multidimensional persistence
Energy Technology Data Exchange (ETDEWEB)
Skryzalin, Jacek [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carlsson, Gunnar [Stanford Univ., Stanford, CA (United States)
2017-05-19
In this paper, we analyze the space of multidimensional persistence modules from the perspectives of algebraic geometry. We first build a moduli space of a certain subclass of easily analyzed multidimensional persistence modules, which we construct specifically to capture much of the information which can be gained by using multidimensional persistence over one-dimensional persistence. We argue that the global sections of this space provide interesting numeric invariants when evaluated against our subclass of multidimensional persistence modules. Lastly, we extend these global sections to the space of all multidimensional persistence modules and discuss how the resulting numeric invariants might be used to study data.
Trace Invariance for Quaternion Matrices
Directory of Open Access Journals (Sweden)
Ralph John de la Cruz
2015-12-01
Full Text Available Let F be a f ield. It is a classical result in linear algebra that for each A, P ϵ Mn (F such that P is nonsingular, tr A = tr (PAP-1. We show in this paper that the preceding property does not hold true if F is the division ring of real quaternions. We show that the only quaternion matrices that have their trace invariant under unitary similarity are Hermitian matrices, and that the only matrices that have their trace invariant under similarity are real scalar matrices.
Pinning down top dipole moments with ultra-boosted tops
Aguilar-Saavedra, Juan A.; Mangano, Michelangelo L.
2015-01-01
We investigate existing and future hadron-collider constraints on the top dipole chromomagnetic and chromoelectric moments, two quantities that are expected to be modified in the presence of new physics. We focus first on recent measurements of the inclusive top pair production cross section at the Tevatron and at the Large Hadron Collider. We then analyse the role of top-antitop events produced at very large invariant masses, in the context of the forthcoming 13-14 TeV runs of the LHC, and at a future 100 TeV proton-proton collider. In this latter case, the selection of semileptonic decays to hard muons allows to tag top quarks boosted to the multi-TeV regime, strongly reducing the QCD backgrounds and leading to a significant improvement in the sensitivity to anomalous top couplings.
Supersymmetric gauge invariant interaction revisited
International Nuclear Information System (INIS)
Smith, A.W.; Pontificia Univ. Catolica do Rio de Janeiro; Barcelos Neto, J.
1983-01-01
A supersymmetric Lagrangian invariant under local U(1) gauge transformations is written in terms of a non-chiral superfield which substitute the usual vector supermultiplet together with chiral and anti-chiral superfields. The Euler equations allow us to obtain the off-shell version of the usual Lagrangian for supersymmetric quantum-electrodynamics (SQED). (Author) [pt
On renormalization-invariant masses
International Nuclear Information System (INIS)
Fleming, H.; Furuya, K.
1978-02-01
It is shown that spontaneous generation of renormalization invariant mass is possible in infra-red stable theories with more than one coupling constant. If relations among the coupling constants are permitted the effect can be made compatible with pertubation theory
Moment Invariants in Image Analysis
Czech Academy of Sciences Publication Activity Database
Flusser, Jan
2006-01-01
Roč. 11, č. 2 (2006), s. 196-201 ISSN 1305-5313 R&D Projects: GA MŠk 1M0572; GA ČR GA102/04/0155 Institutional research plan: CEZ:AV0Z10750506 Keywords : moment invariants * pattern recognition Subject RIV: JD - Computer Applications, Robotics
A Many Particle Adiabatic Invariant
DEFF Research Database (Denmark)
Hjorth, Poul G.
1999-01-01
For a system of N charged particles moving in a homogeneous, sufficiently strong magnetic field, a many-particle adiabatic invariant constrains the collisional exchange of energy between the degrees of freedom perpendicular to and parallel to the magnetic field. A description of the phenomenon...
Recursive bias estimation and L2 boosting
Energy Technology Data Exchange (ETDEWEB)
Hengartner, Nicolas W [Los Alamos National Laboratory; Cornillon, Pierre - Andre [INRA, FRANCE; Matzner - Lober, Eric [RENNE, FRANCE
2009-01-01
This paper presents a general iterative bias correction procedure for regression smoothers. This bias reduction schema is shown to correspond operationally to the L{sub 2} Boosting algorithm and provides a new statistical interpretation for L{sub 2} Boosting. We analyze the behavior of the Boosting algorithm applied to common smoothers S which we show depend on the spectrum of I - S. We present examples of common smoother for which Boosting generates a divergent sequence. The statistical interpretation suggest combining algorithm with an appropriate stopping rule for the iterative procedure. Finally we illustrate the practical finite sample performances of the iterative smoother via a simulation study.
Continuous Integrated Invariant Inference, Phase I
National Aeronautics and Space Administration — The proposed project will develop a new technique for invariant inference and embed this and other current invariant inference and checking techniques in an...
Local unitary invariants for multipartite quantum systems
Energy Technology Data Exchange (ETDEWEB)
Vrana, Peter, E-mail: vranap@math.bme.hu [Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, H-1111 Budapest (Hungary)
2011-03-18
A method is presented to obtain local unitary invariants for multipartite quantum systems consisting of fermions or distinguishable particles. The invariants are organized into infinite families, in particular, the generalization to higher dimensional single-particle Hilbert spaces is straightforward. Many well-known invariants and their generalizations are also included.
Gauge invariant fractional electromagnetic fields
Energy Technology Data Exchange (ETDEWEB)
Lazo, Matheus Jatkoske, E-mail: matheuslazo@furg.br [Instituto de Matematica, Estatistica e Fisica - FURG, Rio Grande, RS (Brazil)
2011-09-26
Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators. -- Highlights: → We propose a fractional Lagrangian formulation for fractional Maxwell's fields. → We obtain gauge invariant fractional electromagnetic fields. → Our generalized fractional Maxwell's field is spatially symmetrical. → We discuss the non-causality of the theory.
Invariance for Single Curved Manifold
Castro, Pedro Machado Manhaes de
2012-08-01
Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.
Holographic multiverse and conformal invariance
Energy Technology Data Exchange (ETDEWEB)
Garriga, Jaume [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08193 Barcelona (Spain); Vilenkin, Alexander, E-mail: jaume.garriga@ub.edu, E-mail: vilenkin@cosmos.phy.tufts.edu [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, 212 College Ave., Medford, MA 02155 (United States)
2009-11-01
We consider a holographic description of the inflationary multiverse, according to which the wave function of the universe is interpreted as the generating functional for a lower dimensional Euclidean theory. We analyze a simple model where transitions between inflationary vacua occur through bubble nucleation, and the inflating part of spacetime consists of de Sitter regions separated by thin bubble walls. In this model, we present some evidence that the dual theory is conformally invariant in the UV.
Molecular invariants: atomic group valence
International Nuclear Information System (INIS)
Mundim, K.C.; Giambiagi, M.; Giambiagi, M.S. de.
1988-01-01
Molecular invariants may be deduced in a very compact way through Grassman algebra. In this work, a generalized valence is defined for an atomic group; it reduces to the Known expressions for the case of an atom in a molecule. It is the same of the correlations between the fluctions of the atomic charges qc and qd (C belongs to the group and D does not) around their average values. Numerical results agree with chemical expectation. (author) [pt
Homotopy invariants of Gauss words
Gibson, Andrew
2009-01-01
By defining combinatorial moves, we can define an equivalence relation on Gauss words called homotopy. In this paper we define a homotopy invariant of Gauss words. We use this to show that there exist Gauss words that are not homotopically equivalent to the empty Gauss word, disproving a conjecture by Turaev. In fact, we show that there are an infinite number of equivalence classes of Gauss words under homotopy.
Random SU(2) invariant tensors
Li, Youning; Han, Muxin; Ruan, Dong; Zeng, Bei
2018-04-01
SU(2) invariant tensors are states in the (local) SU(2) tensor product representation but invariant under the global group action. They are of importance in the study of loop quantum gravity. A random tensor is an ensemble of tensor states. An average over the ensemble is carried out when computing any physical quantities. The random tensor exhibits a phenomenon known as ‘concentration of measure’, which states that for any bipartition the average value of entanglement entropy of its reduced density matrix is asymptotically the maximal possible as the local dimensions go to infinity. We show that this phenomenon is also true when the average is over the SU(2) invariant subspace instead of the entire space for rank-n tensors in general. It is shown in our earlier work Li et al (2017 New J. Phys. 19 063029) that the subleading correction of the entanglement entropy has a mild logarithmic divergence when n = 4. In this paper, we show that for n > 4 the subleading correction is not divergent but a finite number. In some special situation, the number could be even smaller than 1/2, which is the subleading correction of random state over the entire Hilbert space of tensors.
Indian Academy of Sciences (India)
Example 5 (Chameleons): In a certain island there are 13 grey, 15 brown and 17 crimson chameleons. If two chameleons of different colors meet, both of them change to the third color. No other color changes are ... permutation)?' is the question. Well, the set of per- mutations are divided into two classes, odd and even.
Advanced Airfoils Boost Helicopter Performance
2007-01-01
Carson Helicopters Inc. licensed the Langley RC4 series of airfoils in 1993 to develop a replacement main rotor blade for their Sikorsky S-61 helicopters. The company's fleet of S-61 helicopters has been rebuilt to include Langley's patented airfoil design, and the helicopters are now able to carry heavier loads and fly faster and farther, and the main rotor blades have twice the previous service life. In aerial firefighting, the performance-boosting airfoils have helped the U.S. Department of Agriculture's Forest Service control the spread of wildfires. In 2003, Carson Helicopters signed a contract with Ducommun AeroStructures Inc., to manufacture the composite blades for Carson Helicopters to sell
ATLAS boosted object tagging 2
Caudron, Julien; The ATLAS collaboration
2015-01-01
A detailed study into the optimal techniques for identifying boosted hadronically decaying W or Z bosons is presented. Various algorithms for reconstructing, grooming and tagging bosonic jets are compared for W bosons with a wide range of transverse momenta using 8 TeV data and 8 TeV and 13 TeV MC simulations. In addition, given that a hadronic jet has been identified as resulting from the hadronic decay of a W or Z, a technique is developed to discriminate between W and Z bosons. The modeling of the tagging variables used in this technique is studied using 8 TeV pp collision data and systematic uncertainties for the tagger efficiency and fake rates are evaluated.
Blur invariants constructed from arbitrary moments.
Kautsky, Jaroslav; Flusser, Jan
2011-12-01
This paper deals with moment invariants with respect to image blurring. It is mainly a reaction to the works of Zhang and Chen , recently published in these Transactions. We present a general method on how to construct blur invariants from arbitrary moments and show that it is no longer necessary to separately derive the invariants for each polynomial basis. We show how to discard dependent terms in blur invariants definition and discuss a proper implementation of the invariants in orthogonal bases using recurrent relations. An example for Legendre moments is given. © 2011 IEEE
Cartan invariants and event horizon detection
Brooks, D.; Chavy-Waddy, P. C.; Coley, A. A.; Forget, A.; Gregoris, D.; MacCallum, M. A. H.; McNutt, D. D.
2018-04-01
We show that it is possible to locate the event horizon of a black hole (in arbitrary dimensions) by the zeros of certain Cartan invariants. This approach accounts for the recent results on the detection of stationary horizons using scalar polynomial curvature invariants, and improves upon them since the proposed method is computationally less expensive. As an application, we produce Cartan invariants that locate the event horizons for various exact four-dimensional and five-dimensional stationary, asymptotically flat (or (anti) de Sitter), black hole solutions and compare the Cartan invariants with the corresponding scalar curvature invariants that detect the event horizon.
Invariant Classification of Gait Types
DEFF Research Database (Denmark)
Fihl, Preben; Moeslund, Thomas B.
2008-01-01
This paper presents a method of classifying human gait in an invariant manner based on silhouette comparison. A database of artificially generated silhouettes is created representing the three main types of gait, i.e. walking, jogging, and running. Silhouettes generated from different camera angles....... Input silhouettes are matched to the database using the Hungarian method. A classifier is defined based on the dissimilarity between the input silhouettes and the gait actions of the database. The overall recognition rate is 88.2% on a large and diverse test set. The recognition rate is better than...
Quantum Weyl invariance and cosmology
Energy Technology Data Exchange (ETDEWEB)
Dabholkar, Atish, E-mail: atish@ictp.it [International Centre for Theoretical Physics, ICTP-UNESCO, Strada Costiera 11, Trieste 34151 (Italy); Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7589, LPTHE, F-75005, Paris (France)
2016-09-10
Equations for cosmological evolution are formulated in a Weyl invariant formalism to take into account possible Weyl anomalies. Near two dimensions, the renormalized cosmological term leads to a nonlocal energy-momentum tensor and a slowly decaying vacuum energy. A natural generalization to four dimensions implies a quantum modification of Einstein field equations at long distances. It offers a new perspective on time-dependence of couplings and naturalness with potentially far-reaching consequences for the cosmological constant problem, inflation, and dark energy.
Invariant metrics for Hamiltonian systems
International Nuclear Information System (INIS)
Rangarajan, G.; Dragt, A.J.; Neri, F.
1991-05-01
In this paper, invariant metrics are constructed for Hamiltonian systems. These metrics give rise to norms on the space of homeogeneous polynomials of phase-space variables. For an accelerator lattice described by a Hamiltonian, these norms characterize the nonlinear content of the lattice. Therefore, the performance of the lattice can be improved by minimizing the norm as a function of parameters describing the beam-line elements in the lattice. A four-fold increase in the dynamic aperture of a model FODO cell is obtained using this procedure. 7 refs
Orthodontics Align Crooked Teeth and Boost Self-Esteem
... desktop! more... Orthodontics Align Crooked Teeth and Boost Self- esteem Article Chapters Orthodontics Align Crooked Teeth and Boost Self- esteem print full article print this chapter email this ...
Tensor network methods for invariant theory
Biamonte, Jacob; Bergholm, Ville; Lanzagorta, Marco
2013-11-01
Invariant theory is concerned with functions that do not change under the action of a given group. Here we communicate an approach based on tensor networks to represent polynomial local unitary invariants of quantum states. This graphical approach provides an alternative to the polynomial equations that describe invariants, which often contain a large number of terms with coefficients raised to high powers. This approach also enables one to use known methods from tensor network theory (such as the matrix product state (MPS) factorization) when studying polynomial invariants. As our main example, we consider invariants of MPSs. We generate a family of tensor contractions resulting in a complete set of local unitary invariants that can be used to express the Rényi entropies. We find that the graphical approach to representing invariants can provide structural insight into the invariants being contracted, as well as an alternative, and sometimes much simpler, means to study polynomial invariants of quantum states. In addition, many tensor network methods, such as MPSs, contain excellent tools that can be applied in the study of invariants.
Limit Cycles and Conformal Invariance
Fortin, Jean-Francois; Stergiou, Andreas
2013-01-01
There is a widely held belief that conformal field theories (CFTs) require zero beta functions. Nevertheless, the work of Jack and Osborn implies that the beta functions are not actually the quantites that decide conformality, but until recently no such behavior had been exhibited. Our recent work has led to the discovery of CFTs with nonzero beta functions, more precisely CFTs that live on recurrent trajectories, e.g., limit cycles, of the beta-function vector field. To demonstrate this we study the S function of Jack and Osborn. We use Weyl consistency conditions to show that it vanishes at fixed points and agrees with the generator Q of limit cycles on them. Moreover, we compute S to third order in perturbation theory, and explicitly verify that it agrees with our previous determinations of Q. A byproduct of our analysis is that, in perturbation theory, unitarity and scale invariance imply conformal invariance in four-dimensional quantum field theories. Finally, we study some properties of these new, "cycl...
Remark on shape invariant potential
International Nuclear Information System (INIS)
Drigo Filho, Elso; Ricotta, Regina Maria
1997-01-01
For more than a decade, Supersymmetry has provided new information about ordinary quantum mechanical problems, and Supersymmetric Quantum Mechanics has become a field research by itself. If has been shown that the symmetry between two different systems that share energy spectra can be interpreted in terms of supersymmetry. From the knowledge of the ground state of a given potential it is possible to find another potential with the same energy spectrum, except for the ground state. In fact, from the use of supersymmetric partner Hamiltonians and their degeneracy spectra it has become possible to determine a ladder of Hamiltonians and their spectra, only through the ground states of the ladder. Concerning the partner Hamiltonians with potentials V + and V - that are similar in shape but Differ in the parameters. Gedenshtein introduced in 1983 the concept of shape invariance. Here we propose an extension of this concept. It is formulated in terms of the functional form of the whole super-family and not only between any two members of the ladder. We give two examples where all the members of the super-family can be written in a general functional form and conclude that Gedenshtein's conditions of shape invariance is sufficient but not necessary in order to obtain the super-family. (author)
Scale-invariant gravity: geometrodynamics
International Nuclear Information System (INIS)
Anderson, Edward; Barbour, Julian; Foster, Brendan; Murchadha, Niall O
2003-01-01
We present a scale-invariant theory, conformal gravity, which closely resembles the geometrodynamical formulation of general relativity (GR). While previous attempts to create scale-invariant theories of gravity have been based on Weyl's idea of a compensating field, our direct approach dispenses with this and is built by extension of the method of best matching w.r.t. scaling developed in the parallel particle dynamics paper by one of the authors. In spatially compact GR, there is an infinity of degrees of freedom that describe the shape of 3-space which interact with a single volume degree of freedom. In conformal gravity, the shape degrees of freedom remain, but the volume is no longer a dynamical variable. Further theories and formulations related to GR and conformal gravity are presented. Conformal gravity is successfully coupled to scalars and the gauge fields of nature. It should describe the solar system observations as well as GR does, but its cosmology and quantization will be completely different
Modeling of asymmetrical boost converters
Directory of Open Access Journals (Sweden)
Eliana Isabel Arango Zuluaga
2014-01-01
Full Text Available The asymmetrical interleaved dual boost (AIDB is a fifth-order DC/DC converter designed to interface photovoltaic (PV panels. The AIDB produces small current harmonics to the PV panels, reducing the power losses caused by the converter operation. Moreover, the AIDB provides a large voltage conversion ratio, which is required to step-up the PV voltage to the large dc-link voltage used in grid-connected inverters. To reject irradiance and load disturbances, the AIDB must be operated in a closed-loop and a dynamic model is required. Given that the AIDB converter operates in Discontinuous Conduction Mode (DCM, classical modeling approaches based on Continuous Conduction Mode (CCM are not valid. Moreover, classical DCM modeling techniques are not suitable for the AIDB converter. Therefore, this paper develops a novel mathematical model for the AIDB converter, which is suitable for control-pur-poses. The proposed model is based on the calculation of a diode current that is typically disregarded. Moreover, because the traditional correction to the second duty cycle reported in literature is not effective, a new equation is designed. The model accuracy is contrasted with circuital simulations in time and frequency domains, obtaining satisfactory results. Finally, the usefulness of the model in control applications is illustrated with an application example.
CANCER Escape from senescence boosts tumour growth
Medema, Jan Paul
2018-01-01
Some chemotherapies block cancer growth by driving tumour cells into a state of cell-division arrest termed senescence. It emerges that such cells have a boosted capacity to drive tumour growth if they exit senescence
Boosting Learning Algorithm for Stock Price Forecasting
Wang, Chengzhang; Bai, Xiaoming
2018-03-01
To tackle complexity and uncertainty of stock market behavior, more studies have introduced machine learning algorithms to forecast stock price. ANN (artificial neural network) is one of the most successful and promising applications. We propose a boosting-ANN model in this paper to predict the stock close price. On the basis of boosting theory, multiple weak predicting machines, i.e. ANNs, are assembled to build a stronger predictor, i.e. boosting-ANN model. New error criteria of the weak studying machine and rules of weights updating are adopted in this study. We select technical factors from financial markets as forecasting input variables. Final results demonstrate the boosting-ANN model works better than other ones for stock price forecasting.
Avoiding Anemia: Boost Your Red Blood Cells
... Issues Subscribe January 2014 Print this issue Avoiding Anemia Boost Your Red Blood Cells En español Send ... Disease When Blood Cells Bend Wise Choices Preventing Anemia To prevent or treat iron-deficiency anemia: Eat ...
Wilson loop invariants from WN conformal blocks
Directory of Open Access Journals (Sweden)
Oleg Alekseev
2015-12-01
Full Text Available Knot and link polynomials are topological invariants calculated from the expectation value of loop operators in topological field theories. In 3D Chern–Simons theory, these invariants can be found from crossing and braiding matrices of four-point conformal blocks of the boundary 2D CFT. We calculate crossing and braiding matrices for WN conformal blocks with one component in the fundamental representation and another component in a rectangular representation of SU(N, which can be used to obtain HOMFLY knot and link invariants for these cases. We also discuss how our approach can be generalized to invariants in higher-representations of WN algebra.
Top reconstruction and boosted top experimental overview
Skinnari, Louise
2015-01-01
An overview of techniques used to reconstruct resolved and boosted top quarks is presented. Techniques for resolved top quark reconstruction include kinematic likelihood fitters and pseudo- top reconstruction. Many tools and methods are available for the reconstruction of boosted top quarks, such as jet grooming techniques, jet substructure variables, and dedicated top taggers. Different techniques as used by ATLAS and CMS analyses are described and the performance of different variables and top taggers are shown.
Scale invariance in road networks.
Kalapala, Vamsi; Sanwalani, Vishal; Clauset, Aaron; Moore, Cristopher
2006-02-01
We study the topological and geographic structure of the national road networks of the United States, England, and Denmark. By transforming these networks into their dual representation, where roads are vertices and an edge connects two vertices if the corresponding roads ever intersect, we show that they exhibit both topological and geographic scale invariance. That is, we show that for sufficiently large geographic areas, the dual degree distribution follows a power law with exponent 2.2< or = alpha < or =2.4, and that journeys, regardless of their length, have a largely identical structure. To explain these properties, we introduce and analyze a simple fractal model of road placement that reproduces the observed structure, and suggests a testable connection between the scaling exponent and the fractal dimensions governing the placement of roads and intersections.
Invariants of DNA genomic signals
Cristea, Paul Dan A.
2005-02-01
For large scale analysis purposes, the conversion of genomic sequences into digital signals opens the possibility to use powerful signal processing methods for handling genomic information. The study of complex genomic signals reveals large scale features, maintained over the scale of whole chromosomes, that would be difficult to find by using only the symbolic representation. Based on genomic signal methods and on statistical techniques, the paper defines parameters of DNA sequences which are invariant to transformations induced by SNPs, splicing or crossover. Re-orienting concatenated coding regions in the same direction, regularities shared by the genomic material in all exons are revealed, pointing towards the hypothesis of a regular ancestral structure from which the current chromosome structures have evolved. This property is not found in non-nuclear genomic material, e.g., plasmids.
Local invariance via comparison functions
Directory of Open Access Journals (Sweden)
Ovidiu Carja
2004-04-01
Full Text Available We consider the ordinary differential equation $u'(t=f(t,u(t$, where $f:[a,b]imes Do mathbb{R}^n$ is a given function, while $D$ is an open subset in $mathbb{R}^n$. We prove that, if $Ksubset D$ is locally closed and there exists a comparison function $omega:[a,b]imesmathbb{R}_+o mathbb{R}$ such that $$ liminf_{hdownarrow 0}frac{1}{h}ig[d(xi+hf(t,xi;K-d(xi;Kig] leqomega(t,d(xi;K $$ for each $(t,xiin [a,b]imes D$, then $K$ is locally invariant with respect to $f$. We show further that, under some natural extra condition, the converse statement is also true.
Asymptotic invariants of homotopy groups
Manin, Fedor
We study the homotopy groups of a finite CW complex X via constraints on the geometry of representatives of their elements. For example, one can measure the "size" of alpha ∈ pi n (X) by the optimal Lipschitz constant or volume of a representative. By comparing the geometrical structure thus obtained with the algebraic structure of the group, one can define functions such as growth and distortion in pin(X), analogously to the way that such functions are studied in asymptotic geometric group theory. We provide a number of examples and techniques for studying these invariants, with a special focus on spaces with few rational homotopy groups. Our main theorem characterizes those X in which all non-torsion homotopy classes are undistorted, that is, their volume distortion functions, and hence also their Lipschitz distortion functions, are linear.
Scale-invariant extended inflation
International Nuclear Information System (INIS)
Holman, R.; Kolb, E.W.; Vadas, S.L.; Wang, Y.
1991-01-01
We propose a model of extended inflation which makes use of the nonlinear realization of scale invariance involving the dilaton coupled to an inflaton field whose potential admits a metastable ground state. The resulting theory resembles the Jordan-Brans-Dicke version of extended inflation. However, quantum effects, in the form of the conformal anomaly, generate a mass for the dilaton, thus allowing our model to evade the problems of the original version of extended inflation. We show that extended inflation can occur for a wide range of inflaton potentials with no fine-tuning of dimensionless parameters required. Furthermore, we also find that it is quite natural for the extended-inflation period to be followed by an epoch of slow-rollover inflation as the dilaton settles down to the minimum of its induced potential
Chirality invariance and 'chiral' fields
International Nuclear Information System (INIS)
Ziino, G.
1978-01-01
The new field model derived in the present paper actually gives a definite answer to three fundamental questions concerning elementary-particle physics: 1) The phenomenological dualism between parity and chirality invariance: it would be only an apparent display of a general 'duality' principle underlying the intrinsic nature itself of (spin 1/2) fermions and expressed by the anticommutativity property between scalar and pseudoscalar charges. 2) The real physical meaning of V - A current structure: it would exclusively be connected to the one (just pointed out) of chiral fields themselves. 3) The unjustified apparent oddness shown by Nature in weak interactions, for the fact of picking out only one of the two (left- and right-handed) fermion 'chiral' projections: the key to such a 'mystery' would just be provided by the consequences of the dual and partial character of the two fermion-antifermion field bases. (Auth.)
Negation switching invariant signed graphs
Directory of Open Access Journals (Sweden)
Deepa Sinha
2014-04-01
Full Text Available A signed graph (or, $sigraph$ in short is a graph G in which each edge x carries a value $\\sigma(x \\in \\{-, +\\}$ called its sign. Given a sigraph S, the negation $\\eta(S$ of the sigraph S is a sigraph obtained from S by reversing the sign of every edge of S. Two sigraphs $S_{1}$ and $S_{2}$ on the same underlying graph are switching equivalent if it is possible to assign signs `+' (`plus' or `-' (`minus' to vertices of $S_{1}$ such that by reversing the sign of each of its edges that has received opposite signs at its ends, one obtains $S_{2}$. In this paper, we characterize sigraphs which are negation switching invariant and also see for what sigraphs, S and $\\eta (S$ are signed isomorphic.
International Nuclear Information System (INIS)
Siqueira, J.R.R.
1984-01-01
The question of how far the requirement of invariance under the continuous conformal group determines relativistic Schroedinger wave equations for (free) zero mass particles of arbitrary spin is rised. First, the conditions to be satisfied by the Hamiltonian operator appearing in the Schroedinger wave equation i∂Ψ/∂t= H Ψ (with Ψ transforming locally under homogeneous Lorentz transformations) are derived such that the wave equation is invariant individually under boosts, dilatations and special conformal transformations of the conformal group whose generators are in the local forms given by Mack and Salam for Type Ia fields. Then starting with the most general form of the Hamiltonian for the spin s case, invariant under translations and rotations, the boost, dilatational and special conformal invariance conditions are applied on H so as to make an explicit determination of the solutions for H when ψ transforms according (i) D(o,s) (ii) D(s,o) and (iii) D(o,s) + D(s,o) representation of the Homogeneous Lorentz group. (E.G.) [pt
Spontaneously broken abelian gauge invariant supersymmetric model
International Nuclear Information System (INIS)
Mainland, G.B.; Tanaka, K.
A model is presented that is invariant under an Abelian gauge transformation and a modified supersymmetry transformation. This model is broken spontaneously, and the interplay between symmetry breaking, Goldstone particles, and mass breaking is studied. In the present model, spontaneously breaking the Abelian symmetry of the vacuum restores the invariance of the vacuum under a modified supersymmetry transformation. (U.S.)
Invariant subsets under compact quantum group actions
Huang, Huichi
2012-01-01
We investigate compact quantum group actions on unital $C^*$-algebras by analyzing invariant subsets and invariant states. In particular, we come up with the concept of compact quantum group orbits and use it to show that countable compact metrizable spaces with infinitely many points are not quantum homogeneous spaces.
Scale invariant Volkov–Akulov supergravity
Directory of Open Access Journals (Sweden)
S. Ferrara
2015-10-01
Full Text Available A scale invariant goldstino theory coupled to supergravity is obtained as a standard supergravity dual of a rigidly scale-invariant higher-curvature supergravity with a nilpotent chiral scalar curvature. The bosonic part of this theory describes a massless scalaron and a massive axion in a de Sitter Universe.
Superfield approach to symmetry invariance in quantum ...
Indian Academy of Sciences (India)
invariance for the Abelian and non-Abelian 1-form gauge theories where there is an explicit coupling between the 1-form gauge fields and the Dirac fields. It has been established, in the above works [26–28], that the (anti-)BRST invariance of the 4D Lagrangian densities is encoded in the Grassmannian independence of ...
Real object recognition using moment invariants
Indian Academy of Sciences (India)
contour-based shape descriptors and region-based shape descriptors (Kim & Sung 2000). Regular moment invariants are one of the most popular and widely used contour-based shape descriptors is a set of derived by Hu (1962). These geometrical moment invariants have been then extended to larger sets by Wong & Siu ...
Gromov–Witten invariants and quantum cohomology
Indian Academy of Sciences (India)
no local invariant in symplectic geometry, like, for example, the curvature in Riemannian geometry. The only possible invariants have to be global. The Darboux ..... that earlier Donaldson [D] used similar arguments for the orientation of Yang–Mills moduli spaces. Part (b) uses an infinite dimensional version of Sard–Smale ...
A test for ordinal measurement invariance
Ligtvoet, R.; Millsap, R.E.; Bolt, D.M.; van der Ark, L.A.; Wang, W.-C.
2015-01-01
One problem with the analysis of measurement invariance is the reliance of the analysis on having a parametric model that accurately describes the data. In this paper an ordinal version of the property of measurement invariance is proposed, which relies only on nonparametric restrictions. This
Constructing Invariant Fairness Measures for Surfaces
DEFF Research Database (Denmark)
Gravesen, Jens; Ungstrup, Michael
1998-01-01
This paper presents a general method which from an invariant curve fairness measure constructs an invariant surface fairness measure. Besides the curve fairness measure one only needs a class of curves on the surface for which one wants to apply the curve measure. The surface measure at a point...... variation.The method is extended to the case where one considers, not the fairness of one curve, but the fairness of a one parameter family of curves. Such a family is generated by the flow of a vector field, orthogonal to the curves. The first, respectively the second order derivative along the curve...... of the size of this vector field is used as the fairness measure on the family.Six basic 3rd order invariants satisfying two quadratic equations are defined. They form a complete set in the sense that any invariant 3rd order function can be written as a function of the six basic invariants together...
The usage of color invariance in SURF
Meng, Gang; Jiang, Zhiguo; Zhao, Danpei
2009-10-01
SURF (Scale Invariant Feature Transform) is a robust local invariant feature descriptor. However, SURF is mainly designed for gray images. In order to make use of the information provided by color (mainly RGB channels), this paper presents a novel colored local invariant feature descriptor, CISURF (Color Invariance based SURF). The proposed approach builds the descriptors in a color invariant space, which stems from Kubelka-Munk model and provides more valuable information than the gray space. Compared with the conventional SURF and SIFT descriptors, the experimental results show that descriptors created by CISURF is more robust to the circumstance changes such as the illumination direction, illumination intensity, and the viewpoints, and are more suitable for the deep space background objects.
Scale invariant transfer matrices and Hamiltionians
Jones, Vaughan F. R.
2018-03-01
Given a direct system of Hilbert spaces s\\mapsto {\\mathcal H}s (with isometric inclusion maps \\iota_s^t:{\\mathcal H}_s→ {\\mathcal H}t for s≤slant t ) corresponding to quantum systems on scales s, we define notions of scale invariant and weakly scale invariant operators. In some cases of quantum spin chains we find conditions for transfer matrices and nearest neighbour Hamiltonians to be scale invariant or weakly so. Scale invariance forces spatial inhomogeneity of the spectral parameter. But weakly scale invariant transfer matrices may be spatially homogeneous in which case the change of spectral parameter from one scale to another is governed by a classical dynamical system exhibiting fractal behaviour.
Experimental tests of confinement scale invariance on JET, DIIID, ASDEX Upgrade and CMOD
International Nuclear Information System (INIS)
Christiansen, J.P.; Cordey, J.G.; Budny, R.
2001-01-01
An international collaboration between JET, DIIID, AUG and CMOD has resulted in four sets of Tokamak discharges which are approximately identical as regards a set of dimensionless plasma variables. The data demonstrates some measure of scale invariance of local and global confinement but a more accurate matching of scaled density, power etc. is required to make firmer conclusions. (author)
Modeling of Laser wakefield acceleration in the Lorentz boosted frame using UPIC-EMMA and OSIRIS
Yu, Peicheng; Xu, Xinlu; Decyk, Viktor; Tsung, Frank; Vieira, Jorge; Fonseca, Ricardo; Lu, Wei; Silva, Luis; Mori, Warren; UCLA Team; Tsinghua University Beijing Team; IST Portugal Team
2014-10-01
We present the capability of investigating physics of laser wakefield accelerator (LWFA) in nonlinear regimes using various approaches. This includes simulating the physics using OSIRIS 3D code in the lab and boosted frame. We also implemented hybrid 3D algorithm into OSIRIS which uses an algorithm with a PIC description in r-z and a gridless description in phi [A. F. Lifschitz et al., JCP. 228, 1803 (2009)]. This algorithm greatly reduce the computation load by describing the three-dimensional (3D) physics problem of laser-plasma interaction with essentially two-dimensional if the expansion is truncated. The hybrid 3D OSIRIS code can be used to simulate the nonlinear physics in LWFA in both lab and boosted frames. Combining the hybrid 3D and boosted frame approaches potentially provides unprecedented speedups. Furthermore, we can simulate the same problems in a boosted frame using the spectral EM-PIC code UPIC-EMMA which solves the Maxwell's equation in Fourier space. By applying a recipe to systematically reduce the numerical Cerenkov instability (NCI) in the spspectral code, we are able to conduct LWFA Lorentz boosted frame simulation at arbitrary gamma with no signs of NCI.
Rotational Invariant Dimensionality Reduction Algorithms.
Lai, Zhihui; Xu, Yong; Yang, Jian; Shen, Linlin; Zhang, David
2017-11-01
A common intrinsic limitation of the traditional subspace learning methods is the sensitivity to the outliers and the image variations of the object since they use the norm as the metric. In this paper, a series of methods based on the -norm are proposed for linear dimensionality reduction. Since the -norm based objective function is robust to the image variations, the proposed algorithms can perform robust image feature extraction for classification. We use different ideas to design different algorithms and obtain a unified rotational invariant (RI) dimensionality reduction framework, which extends the well-known graph embedding algorithm framework to a more generalized form. We provide the comprehensive analyses to show the essential properties of the proposed algorithm framework. This paper indicates that the optimization problems have global optimal solutions when all the orthogonal projections of the data space are computed and used. Experimental results on popular image datasets indicate that the proposed RI dimensionality reduction algorithms can obtain competitive performance compared with the previous norm based subspace learning algorithms.
Stereo Correspondence Using Moment Invariants
Premaratne, Prashan; Safaei, Farzad
Autonomous navigation is seen as a vital tool in harnessing the enormous potential of Unmanned Aerial Vehicles (UAV) and small robotic vehicles for both military and civilian use. Even though, laser based scanning solutions for Simultaneous Location And Mapping (SLAM) is considered as the most reliable for depth estimation, they are not feasible for use in UAV and land-based small vehicles due to their physical size and weight. Stereovision is considered as the best approach for any autonomous navigation solution as stereo rigs are considered to be lightweight and inexpensive. However, stereoscopy which estimates the depth information through pairs of stereo images can still be computationally expensive and unreliable. This is mainly due to some of the algorithms used in successful stereovision solutions require high computational requirements that cannot be met by small robotic vehicles. In our research, we implement a feature-based stereovision solution using moment invariants as a metric to find corresponding regions in image pairs that will reduce the computational complexity and improve the accuracy of the disparity measures that will be significant for the use in UAVs and in small robotic vehicles.
A scale invariance criterion for LES parametrizations
Directory of Open Access Journals (Sweden)
Urs Schaefer-Rolffs
2015-01-01
Full Text Available Turbulent kinetic energy cascades in fluid dynamical systems are usually characterized by scale invariance. However, representations of subgrid scales in large eddy simulations do not necessarily fulfill this constraint. So far, scale invariance has been considered in the context of isotropic, incompressible, and three-dimensional turbulence. In the present paper, the theory is extended to compressible flows that obey the hydrostatic approximation, as well as to corresponding subgrid-scale parametrizations. A criterion is presented to check if the symmetries of the governing equations are correctly translated into the equations used in numerical models. By applying scaling transformations to the model equations, relations between the scaling factors are obtained by demanding that the mathematical structure of the equations does not change.The criterion is validated by recovering the breakdown of scale invariance in the classical Smagorinsky model and confirming scale invariance for the Dynamic Smagorinsky Model. The criterion also shows that the compressible continuity equation is intrinsically scale-invariant. The criterion also proves that a scale-invariant turbulent kinetic energy equation or a scale-invariant equation of motion for a passive tracer is obtained only with a dynamic mixing length. For large-scale atmospheric flows governed by the hydrostatic balance the energy cascade is due to horizontal advection and the vertical length scale exhibits a scaling behaviour that is different from that derived for horizontal length scales.
Feedback-Driven Dynamic Invariant Discovery
Zhang, Lingming; Yang, Guowei; Rungta, Neha S.; Person, Suzette; Khurshid, Sarfraz
2014-01-01
Program invariants can help software developers identify program properties that must be preserved as the software evolves, however, formulating correct invariants can be challenging. In this work, we introduce iDiscovery, a technique which leverages symbolic execution to improve the quality of dynamically discovered invariants computed by Daikon. Candidate invariants generated by Daikon are synthesized into assertions and instrumented onto the program. The instrumented code is executed symbolically to generate new test cases that are fed back to Daikon to help further re ne the set of candidate invariants. This feedback loop is executed until a x-point is reached. To mitigate the cost of symbolic execution, we present optimizations to prune the symbolic state space and to reduce the complexity of the generated path conditions. We also leverage recent advances in constraint solution reuse techniques to avoid computing results for the same constraints across iterations. Experimental results show that iDiscovery converges to a set of higher quality invariants compared to the initial set of candidate invariants in a small number of iterations.
Centrifugal compressor design for electrically assisted boost
Y Yang, M.; Martinez-Botas, R. F.; Zhuge, W. L.; Qureshi, U.; Richards, B.
2013-12-01
Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically.
An Update on Statistical Boosting in Biomedicine
Directory of Open Access Journals (Sweden)
Andreas Mayr
2017-01-01
Full Text Available Statistical boosting algorithms have triggered a lot of research during the last decade. They combine a powerful machine learning approach with classical statistical modelling, offering various practical advantages like automated variable selection and implicit regularization of effect estimates. They are extremely flexible, as the underlying base-learners (regression functions defining the type of effect for the explanatory variables can be combined with any kind of loss function (target function to be optimized, defining the type of regression setting. In this review article, we highlight the most recent methodological developments on statistical boosting regarding variable selection, functional regression, and advanced time-to-event modelling. Additionally, we provide a short overview on relevant applications of statistical boosting in biomedicine.
Improved Stereo Matching With Boosting Method
Directory of Open Access Journals (Sweden)
Shiny B
2015-06-01
Full Text Available Abstract This paper presents an approach based on classification for improving the accuracy of stereo matching methods. We propose this method for occlusion handling. This work employs classification of pixels for finding the erroneous disparity values. Due to the wide applications of disparity map in 3D television medical imaging etc the accuracy of disparity map has high significance. An initial disparity map is obtained using local or global stereo matching methods from the input stereo image pair. The various features for classification are computed from the input stereo image pair and the obtained disparity map. Then the computed feature vector is used for classification of pixels by using GentleBoost as the classification method. The erroneous disparity values in the disparity map found by classification are corrected through a completion stage or filling stage. A performance evaluation of stereo matching using AdaBoostM1 RUSBoost Neural networks and GentleBoost is performed.
Transformer Isolated Buck-Boost Converters
Directory of Open Access Journals (Sweden)
Barry W. Williams
2016-12-01
Full Text Available Of the single-switch dc-to-dc converters, those with the buck-boost voltage transfer function offer most potential for transformer coupling, hence isolation, at the kilowatt level. This paper highlights the limitations of the traditional magnetic coupled, buck-boost topology. Then four split-capacitor transformer-coupled topologies (specifically the Cuk, sepic, zeta, and a new, converters with a common ac equivalent circuit are explored, that do not temporarily store core magnetic energy as does the traditional isolated buck-boost converter nor have a core dc magnetizing current bias, as with the sepic and zeta transformer coupled topologies. Core dc bias capacitive voltage compensation is a practical design constraint in three of the four topologies, while all four must cater for stray and leakage inductance effects. Simulations and experimental results for the new converter at 408W support the transformer-coupled, single-switch dc-to-dc converter concepts investigated.
Gromov–Witten invariants and localization
International Nuclear Information System (INIS)
Morrison, David R
2017-01-01
We give a pedagogical review of the computation of Gromov–Witten invariants via localization in 2D gauged linear sigma models. We explain the relationship between the two-sphere partition function of the theory and the Kähler potential on the conformal manifold. We show how the Kähler potential can be assembled from classical, perturbative, and non-perturbative contributions, and explain how the non-perturbative contributions are related to the Gromov–Witten invariants of the corresponding Calabi–Yau manifold. We then explain how localization enables efficient calculation of the two-sphere partition function and, ultimately, the Gromov–Witten invariants themselves. (topical review)
Topological excitations in U(1) -invariant theories
International Nuclear Information System (INIS)
Savit, R.
1977-01-01
A class of U(1) -invariant theories in d dimensions is introduced on a lattice. These theories are labeled by a simplex number s, with 1 < or = s < d. The case with s = 1 is the X-Y model; and s = 2 gives compact photodynamics. An exact duality transformation is applied to show that the U(1) -invariant theory in d dimensions with simplex number s is the same as a similar theory in d dimensions but which is Z /sub infinity/-invariant and has simplex number s = d-s. This dual theory describes the topological excitations of the original theory. These excitations are of dimension s - 1
Comment on ``Pairing interaction and Galilei invariance''
Arias, J. M.; Gallardo, M.; Gómez-Camacho, J.
1999-05-01
A recent article by Dussel, Sofia, and Tonina studies the relation between Galilei invariance and dipole energy weighted sum rule (EWSR). The authors find that the pairing interaction, which is neither Galilei nor Lorentz invariant, produces big changes in the EWSR and in effective masses of the nucleons. They argue that these effects of the pairing force could be realistic. In this Comment we stress the validity of Galilei invariance to a very good approximation in this context of low-energy nuclear physics and show that the effective masses and the observed change in the EWSR for the electric dipole operator relative to its classical value are compatible with this symmetry.
Simultaneity as an Invariant Equivalence Relation
Mamone-Capria, Marco
2012-11-01
This paper deals with the concept of simultaneity in classical and relativistic physics as construed in terms of group-invariant equivalence relations. A full examination of Newton, Galilei and Poincaré invariant equivalence relations in ℝ4 is presented, which provides alternative proofs, additions and occasionally corrections of results in the literature, including Malament's theorem and some of its variants. It is argued that the interpretation of simultaneity as an invariant equivalence relation, although interesting for its own sake, does not cut in the debate concerning the conventionality of simultaneity in special relativity.
Multiperiod Maximum Loss is time unit invariant.
Kovacevic, Raimund M; Breuer, Thomas
2016-01-01
Time unit invariance is introduced as an additional requirement for multiperiod risk measures: for a constant portfolio under an i.i.d. risk factor process, the multiperiod risk should equal the one period risk of the aggregated loss, for an appropriate choice of parameters and independent of the portfolio and its distribution. Multiperiod Maximum Loss over a sequence of Kullback-Leibler balls is time unit invariant. This is also the case for the entropic risk measure. On the other hand, multiperiod Value at Risk and multiperiod Expected Shortfall are not time unit invariant.
Quadratic Boost A-Source Impedance Network
DEFF Research Database (Denmark)
Siwakoti, Yam Prasad; Blaabjerg, Frede; Chub, Andrii
2016-01-01
A novel quadratic boost A-source impedance network is proposed to realize converters that demand very high voltage gain. To satisfy the requirement, the network uses an autotransformer where the obtained gain is quadratically dependent on the duty ratio and is unmatched by any existing impedance...... source networks and normal dc-dc converters with coupled magnetics at the same duty ratio and turns ratio. The term “Quadratic Boost A-Source” indicates its quadratic varying gain in the operating principle of the converter. The proposed converter draws a continuous current from the source and suits...
Invariant Measures of Genetic Recombination Processes
Akopyan, Arseniy V.; Pirogov, Sergey A.; Rybko, Aleksandr N.
2015-07-01
We construct a non-linear Markov process connected with a biological model of a bacterial genome recombination. The description of invariant measures of this process gives us the solution of one problem in elementary probability theory.
Ermakov–Lewis invariants and Reid systems
International Nuclear Information System (INIS)
Mancas, Stefan C.; Rosu, Haret C.
2014-01-01
Reid's mth-order generalized Ermakov systems of nonlinear coupling constant α are equivalent to an integrable Emden–Fowler equation. The standard Ermakov–Lewis invariant is discussed from this perspective, and a closed formula for the invariant is obtained for the higher-order Reid systems (m≥3). We also discuss the parametric solutions of these systems of equations through the integration of the Emden–Fowler equation and present an example of a dynamical system for which the invariant is equivalent to the total energy. - Highlights: • Reid systems of order m are connected to Emden–Fowler equations. • General expressions for the Ermakov–Lewis invariants both for m=2 and m≥3 are obtained. • Parametric solutions of the Emden–Fowler equations related to Reid systems are obtained
Borromean surgery formula for the Casson invariant
DEFF Research Database (Denmark)
Meilhan, Jean-Baptiste Odet Thierry
2008-01-01
It is known that every oriented integral homology 3-sphere can be obtained from S3 by a finite sequence of Borromean surgeries. We give an explicit formula for the variation of the Casson invariant under such a surgery move. The formula involves simple classical invariants, namely the framing, li......, linking number and Milnor's triple linking number. A more general statement, for n independent Borromean surgeries, is also provided.......It is known that every oriented integral homology 3-sphere can be obtained from S3 by a finite sequence of Borromean surgeries. We give an explicit formula for the variation of the Casson invariant under such a surgery move. The formula involves simple classical invariants, namely the framing...
Ermakov–Lewis invariants and Reid systems
Energy Technology Data Exchange (ETDEWEB)
Mancas, Stefan C., E-mail: stefan.mancas@erau.edu [Department of Mathematics, Embry-Riddle Aeronautical University, Daytona Beach, FL 32114-3900 (United States); Rosu, Haret C., E-mail: hcr@ipicyt.edu.mx [IPICyT, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San José 2055, Col. Lomas 4a Sección, 78216 San Luis Potosí, S.L.P. (Mexico)
2014-06-13
Reid's mth-order generalized Ermakov systems of nonlinear coupling constant α are equivalent to an integrable Emden–Fowler equation. The standard Ermakov–Lewis invariant is discussed from this perspective, and a closed formula for the invariant is obtained for the higher-order Reid systems (m≥3). We also discuss the parametric solutions of these systems of equations through the integration of the Emden–Fowler equation and present an example of a dynamical system for which the invariant is equivalent to the total energy. - Highlights: • Reid systems of order m are connected to Emden–Fowler equations. • General expressions for the Ermakov–Lewis invariants both for m=2 and m≥3 are obtained. • Parametric solutions of the Emden–Fowler equations related to Reid systems are obtained.
Testing Lorentz invariance of dark matter
Energy Technology Data Exchange (ETDEWEB)
Blas, Diego [Theory Group, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Ivanov, Mikhail M.; Sibiryakov, Sergey, E-mail: diego.blas@cern.ch, E-mail: mm.ivanov@physics.msu.ru, E-mail: sibir@inr.ac.ru [Faculty of Physics, Moscow State University, Vorobjevy Gory, 119991 Moscow (Russian Federation)
2012-10-01
We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.
Testing Lorentz invariance of dark matter
Blas, Diego; Sibiryakov, Sergey
2012-01-01
We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.
Modified dispersion relations, inflation, and scale invariance
Bianco, Stefano; Friedhoff, Victor Nicolai; Wilson-Ewing, Edward
2018-02-01
For a certain type of modified dispersion relations, the vacuum quantum state for very short wavelength cosmological perturbations is scale-invariant and it has been suggested that this may be the source of the scale-invariance observed in the temperature anisotropies in the cosmic microwave background. We point out that for this scenario to be possible, it is necessary to redshift these short wavelength modes to cosmological scales in such a way that the scale-invariance is not lost. This requires nontrivial background dynamics before the onset of standard radiation-dominated cosmology; we demonstrate that one possible solution is inflation with a sufficiently large Hubble rate, for this slow roll is not necessary. In addition, we also show that if the slow-roll condition is added to inflation with a large Hubble rate, then for any power law modified dispersion relation quantum vacuum fluctuations become nearly scale-invariant when they exit the Hubble radius.
Is quantum entanglement invariant in special relativity?
Ahn, D.; Lee, H. J.; Hwang, S. W.; Kim, M. S.
2003-01-01
Quantum entanglements are of fundamental importance in quantum physics ranging from the quantum information processing to the physics of black hole. Here, we show that the quantum entanglement is not invariant in special relativity. This suggests that nearly all aspects of quantum information processing would be affected significantly when relativistic effects are considered because present schemes are based on the general assumption that entanglement is invariant. There should be additional ...
Computer calculation of Witten's 3-manifold invariant
International Nuclear Information System (INIS)
Freed, D.S.; Gompf, R.E.
1991-01-01
Witten's 2+1 dimensional Chern-Simons theory is exactly solvable. We compute the partition function, a topological invariant of 3-manifolds, on generalized Seifert spaces. Thus we test the path integral using the theory of 3-manifolds. In particular, we compare the exact solution with the asymptotic formula predicted by perturbation theory. We conclude that this path integral works as advertised and gives an effective topological invariant. (orig.)
Absolute space-time and realism in Lorentz invariant interpretations of quantum mechanics
Combourieu, Marie-Christine; Vigier, Jean-Pierre
1993-04-01
The assertion that Lorentz invariance must necessarily be violated in models aimed at giving a realistic account of quantum theory is shown to be incorrect. Assuming that an absolute curved system ofaxes forms the envelope of Local inertial frames where the 2.7 K radiation field as the preferred frame is isotropic, we demonstrate that Lorentz invariance, as well as covariance, stil apply to quantum mechanics in all frames of reference whenever Einstein and de Broglie's theory of light, recently revisited by Vigier [IEEE Trans. Plasma Sci. 18 (1990) 64; in: Proc. ISQM-SAT Conf.], is considered.
Niacin to Boost Your HDL "Good" Cholesterol
Niacin can boost 'good' cholesterol Niacin is a B vitamin that may raise your HDL ("good") cholesterol. But side effects might outweigh benefits for most ... been used to increase high-density lipoprotein (HDL) cholesterol — the "good" cholesterol that helps remove low-density ...
Detection of Illegitimate Emails using Boosting Algorithm
DEFF Research Database (Denmark)
Nizamani, Sarwat; Memon, Nasrullah; Wiil, Uffe Kock
2011-01-01
In this paper, we report on experiments to detect illegitimate emails using boosting algorithm. We call an email illegitimate if it is not useful for the receiver or for the society. We have divided the problem into two major areas of illegitimate email detection: suspicious email detection and s...
Boosting China's research collaboration | IDRC - International ...
International Development Research Centre (IDRC) Digital Library (Canada)
Boosting China's research collaboration. Rong Li presenting. Rong Li. Research Awards ... “China's cooperation to date has also largely ignored the role of research collaboration,” he says. Li focused on what China's foreign ... It was my first time formally working abroad,” he says. “It will definitely benefit my future career.”.
Schools Enlisting Defense Industry to Boost STEM
Trotter, Andrew
2008-01-01
Defense contractors Northrop Grumman Corp. and Lockheed Martin Corp. are joining forces in an innovative partnership to develop high-tech simulations to boost STEM--or science, technology, engineering, and mathematics--education in the Baltimore County schools. The Baltimore County partnership includes the local operations of two major military…
The Attentional Boost Effect with Verbal Materials
Mulligan, Neil W.; Spataro, Pietro; Picklesimer, Milton
2014-01-01
Study stimuli presented at the same time as unrelated targets in a detection task are better remembered than stimuli presented with distractors. This attentional boost effect (ABE) has been found with pictorial (Swallow & Jiang, 2010) and more recently verbal materials (Spataro, Mulligan, & Rossi-Arnaud, 2013). The present experiments…
Boosting youth employment prospects in Tanzania | IDRC ...
International Development Research Centre (IDRC) Digital Library (Canada)
2015-12-16
Dec 16, 2015 ... Read the brief, Boosting youth employment prospects: Tanzania, (PDF, 999 KB); Read full report, Youth employment in Tanzania: Taking stock of the evidence and knowledge gaps, (1.14 MB); For a visual representation of the key findings see the infographic poster (PDF, 296 KB). Return to main page, ...
The Attentional Boost Effect and Context Memory
Mulligan, Neil W.; Smith, S. Adam; Spataro, Pietro
2016-01-01
Stimuli co-occurring with targets in a detection task are better remembered than stimuli co-occurring with distractors--the attentional boost effect (ABE). The ABE is of interest because it is an exception to the usual finding that divided attention during encoding impairs memory. The effect has been demonstrated in tests of item memory but it is…
Extending statistical boosting. An overview of recent methodological developments.
Mayr, A; Binder, H; Gefeller, O; Schmid, M
2014-01-01
Boosting algorithms to simultaneously estimate and select predictor effects in statistical models have gained substantial interest during the last decade. This review highlights recent methodological developments regarding boosting algorithms for statistical modelling especially focusing on topics relevant for biomedical research. We suggest a unified framework for gradient boosting and likelihood-based boosting (statistical boosting) which have been addressed separately in the literature up to now. The methodological developments on statistical boosting during the last ten years can be grouped into three different lines of research: i) efforts to ensure variable selection leading to sparser models, ii) developments regarding different types of predictor effects and how to choose them, iii) approaches to extend the statistical boosting framework to new regression settings. Statistical boosting algorithms have been adapted to carry out unbiased variable selection and automated model choice during the fitting process and can nowadays be applied in almost any regression setting in combination with a large amount of different types of predictor effects.
Internal transport barriers in plasmas with reversed plasma flow
Ferro, R. M.; Caldas, I. L.
2018-04-01
Evidences of internal particle transport barriers have been observed in plasma discharges with reversed plasma flow. To investigate the influence of the radial electric field profile on these barriers, we apply a drift wave map that describe the plasma particle transport and allows the integration of particle drift in the presence of a given electrostatic turbulence spectrum. With this procedure we show that transport barriers due to the shearless flow invariant lines are created inside the plasma. Moreover, by varying the radial electric field profile, we observe the formation and destruction of internal transport barriers constituted by shearless invariant lines, as well as its effects on the transport in the map's phase space. Applicability of our results are discussed for the Texas Helimak, a toroidal plasma device in which the radial electric field can be changed by application of bias potential.
Primary Paralleled Isolated Boost Converter with Extended Operating Voltage Range
DEFF Research Database (Denmark)
Hernandez Botella, Juan Carlos; Sen, Gökhan; Mira Albert, Maria del Carmen
2012-01-01
Applications requiring wide input and output voltage range cannot often be satisfied by using buck or boost derived topologies. Primary paralleled isolated boost converter (PPIBC) [1]-[2] is a high efficiency boost derived topology. This paper proposes a new operation mode for extending the input...
The boost transistor: a field plate controlled LDMOST
Ferrara, A.; Schmitz, Jurriaan; Boksteen, B.K.; Hueting, Raymond Josephus Engelbart; Steeneken, P.G.; Heringa, A.; Claes, J.; van der Wel, A.P.
2015-01-01
In this work we present a new device: the boost transistor. The boost transistor is an LDMOS transistor that is controlled by a separate field plate boost electrode that reduces the specific on-resistance RonA. By applying a positive voltage Vboost, this electrode creates an accumulation layer in
Chesler, Paul M.
We study dynamics in conformal field theories with gravitational duals. Attention is focused on heavy and light quark jets as well as far-from-equilibrium dynamics. The stress-energy tensor of a heavy quark moving through a strongly coupled N = 4 supersymmetric Yang-Mills plasma is evaluated using gauge/gravity duality. The accuracy with which the resulting wake, in position space, is reproduced by hydrodynamics is examined. Remarkable agreement is found between hydrodynamics and the complete result down to distances less than 2/ T away from the quark. We also compute the penetration depth of a light quark moving through a N = 4 supersymmetric Yang-Mills plasma using a combination of analytic and numerical techniques. We find that the maximum distance a quark with energy E can travel through a plasma is given by Dxmax E= C/T E/Tl 1/3 with C ≈ 0.5. For the study of dynamics far-from-equilibrium, we consider the creation and evolution of boost invariant anisotropic, strongly coupled conformal plasma. In the dual gravitational description, this corresponds to horizon formation in a geometry driven to be anisotropic by a time-dependent change in boundary conditions.
Yu, Peicheng; Xu, Xinlu; Davidson, Asher; Tableman, Adam; Dalichaouch, Thamine; Li, Fei; Meyers, Michael D.; An, Weiming; Tsung, Frank S.; Decyk, Viktor K.; Fiuza, Frederico; Vieira, Jorge; Fonseca, Ricardo A.; Lu, Wei; Silva, Luis O.; Mori, Warren B.
2016-07-01
When modeling laser wakefield acceleration (LWFA) using the particle-in-cell (PIC) algorithm in a Lorentz boosted frame, the plasma is drifting relativistically at βb c towards the laser, which can lead to a computational speedup of ∼ γb2 =(1 - βb2)- 1. Meanwhile, when LWFA is modeled in the quasi-3D geometry in which the electromagnetic fields and current are decomposed into a limited number of azimuthal harmonics, speedups are achieved by modeling three dimensional (3D) problems with the computational loads on the order of two dimensional r - z simulations. Here, we describe a method to combine the speedups from the Lorentz boosted frame and quasi-3D algorithms. The key to the combination is the use of a hybrid Yee-FFT solver in the quasi-3D geometry that significantly mitigates the Numerical Cerenkov Instability (NCI) which inevitably arises in a Lorentz boosted frame due to the unphysical coupling of Langmuir modes and EM modes of the relativistically drifting plasma in these simulations. In addition, based on the space-time distribution of the LWFA data in the lab and boosted frame, we propose to use a moving window to follow the drifting plasma, instead of following the laser driver as is done in the LWFA lab frame simulations, in order to further reduce the computational loads. We describe the details of how the NCI is mitigated for the quasi-3D geometry, the setups for simulations which combine the Lorentz boosted frame, quasi-3D geometry, and the use of a moving window, and compare the results from these simulations against their corresponding lab frame cases. Good agreement is obtained among these sample simulations, particularly when there is no self-trapping, which demonstrates it is possible to combine the Lorentz boosted frame and the quasi-3D algorithms when modeling LWFA. We also discuss the preliminary speedups achieved in these sample simulations.
Substructure of Highly Boosted Massive Jets
Energy Technology Data Exchange (ETDEWEB)
Alon, Raz [Weizmann Inst. of Science, Rehovot (Israel)
2012-10-01
Modern particle accelerators enable researchers to study new high energy frontiers which have never been explored before. This realm opens possibilities to further examine known fields such as Quantum Chromodynamics. In addition, it allows searching for new physics and setting new limits on the existence of such. This study examined the substructure of highly boosted massive jets measured by the CDF II detector. Events from 1.96 TeV proton-antiproton collisions at the Fermilab Tevatron Collider were collected out of a total integrated luminosity of 5.95 fb$^{-1}$. They were selected to have at least one jet with transverse momentum above 400 GeV/c. The jet mass, angularity, and planar flow were measured and compared with predictions of perturbative Quantum Chromodynamics, and were found to be consistent with the theory. A search for boosted top quarks was conducted and resulted in an upper limit on the production cross section of such top quarks.
Boosting Nonlinear Additive Autoregressive Time Series
Shafik, Nivien; Tutz, Gerhard
2007-01-01
Within the last years several methods for the analysis of nonlinear autoregressive time series have been proposed. As in linear autoregressive models main problems are model identification, estimation and prediction. A boosting method is proposed that performs model identification and estimation simultaneously within the framework of nonlinear autoregressive time series. The method allows to select influential terms from a large numbers of potential lags and exogenous variables. The influence...
Cash boost to Great British science unveiled
2002-01-01
"Trade and Industry Secretary, Patricia Hewitt today unveiled new plans for the DTI's record science budget over the next three years, to keep Britain at the forefront of world science. The plans include funding to develop life saving new health techniques, to seek alternative energy sources, to help our rural economy, to develop the computers of tomorrow and boost business with the next generation of leading edge technologies" (1 page).
Change of adiabatic invariant near the separatrix
International Nuclear Information System (INIS)
Bulanov, S.V.
1995-10-01
The properties of particle motion in the vicinity of the separatrix in a phase plane are investigated. The change of adiabatic invariant value due to the separatrix crossing is evaluated as a function of a perturbation parameter magnitude and a phase of a particle for time dependent Hamiltonians. It is demonstrated that the change of adiabatic invariant value near the separatrix birth is much larger than that in the case of the separatrix crossing near the saddle point in a phase plane. The conditions of a stochastic regime to appear around the separatrix are found. The results are applied to study the longitudinal invariant behaviour of charged particles near singular lines of the magnetic field. (author). 22 refs, 9 figs
Spin foam diagrammatics and topological invariance
International Nuclear Information System (INIS)
Girelli, Florian; Oeckl, Robert; Perez, Alejandro
2002-01-01
We provide a simple proof of the topological invariance of the Turaev-Viro model (corresponding to simplicial 3D pure Euclidean gravity with cosmological constant) by means of a novel diagrammatic formulation of the state sum models for quantum BF theories. Moreover, we prove the invariance under more general conditions allowing the state sum to be defined on arbitrary cellular decompositions of the underlying manifold. Invariance is governed by a set of identities corresponding to local gluing and rearrangement of cells in the complex. Due to the fully algebraic nature of these identities our results extend to a vast class of quantum groups. The techniques introduced here could be relevant for investigating the scaling properties of non-topological state sums, proposed as models of quantum gravity in 4D, under refinement of the cellular decomposition
Blurred image recognition by legendre moment invariants
Zhang, Hui; Shu, Huazhong; Han, Guo-Niu; Coatrieux, Gouenou; Luo, Limin; Coatrieux, Jean-Louis
2010-01-01
Processing blurred images is a key problem in many image applications. Existing methods to obtain blur invariants which are invariant with respect to centrally symmetric blur are based on geometric moments or complex moments. In this paper, we propose a new method to construct a set of blur invariants using the orthogonal Legendre moments. Some important properties of Legendre moments for the blurred image are presented and proved. The performance of the proposed descriptors is evaluated with various point-spread functions and different image noises. The comparison of the present approach with previous methods in terms of pattern recognition accuracy is also provided. The experimental results show that the proposed descriptors are more robust to noise and have better discriminative power than the methods based on geometric or complex moments. PMID:19933003
Knot invariants and higher representation theory
Webster, Ben
2018-01-01
The author constructs knot invariants categorifying the quantum knot variants for all representations of quantum groups. He shows that these invariants coincide with previous invariants defined by Khovanov for \\mathfrak{sl}_2 and \\mathfrak{sl}_3 and by Mazorchuk-Stroppel and Sussan for \\mathfrak{sl}_n. The author's technique is to study 2-representations of 2-quantum groups (in the sense of Rouquier and Khovanov-Lauda) categorifying tensor products of irreducible representations. These are the representation categories of certain finite dimensional algebras with an explicit diagrammatic presentation, generalizing the cyclotomic quotient of the KLR algebra. When the Lie algebra under consideration is \\mathfrak{sl}_n, the author shows that these categories agree with certain subcategories of parabolic category \\mathcal{O} for \\mathfrak{gl}_k.
Boosted Random Ferns for Object Detection.
Vergel, Michael Villamizar; Andrade-Cetto, Juan; Sanfeliu, Alberto; Moreno-Noguer, Francesc
2018-02-01
In this paper we introduce the Boosted Random Ferns (BRFs) to rapidly build discriminative classifiers for learning and detecting object categories. At the core of our approach we use standard random ferns, but we introduce four main innovations that let us bring ferns from an instance to a category level, and still retain efficiency. First, we define binary features on the histogram of oriented gradients-domain (as opposed to intensity-), allowing for a better representation of intra-class variability. Second, both the positions where ferns are evaluated within the sliding window, and the location of the binary features for each fern are not chosen completely at random, but instead we use a boosting strategy to pick the most discriminative combination of them. This is further enhanced by our third contribution, that is to adapt the boosting strategy to enable sharing of binary features among different ferns, yielding high recognition rates at a low computational cost. And finally, we show that training can be performed online, for sequentially arriving images. Overall, the resulting classifier can be very efficiently trained, densely evaluated for all image locations in about 0.1 seconds, and provides detection rates similar to competing approaches that require expensive and significantly slower processing times. We demonstrate the effectiveness of our approach by thorough experimentation in publicly available datasets in which we compare against state-of-the-art, and for tasks of both 2D detection and 3D multi-view estimation.
Fast neutron boost for the treatment of grade IV astrocytomas
International Nuclear Information System (INIS)
Breteau, N.; Destembert, B.; Favre, A.; Pheline, C.; Schlienger, M.
1989-01-01
A previous study, on grade IV astrocytomas, compared a combination of photons and fast neutron boost to photons only, both treatments being delivered following a concentrated irradiation schedule. A slight improvement in survival was observed after neutron boost for non operated patients, but not for operated patients. Since death was always related to local recurrence and since no complication occurred after neutron boost, the neutron dose was increased from 6 to 7 Gy in January 1985. No improvement in survival was observed for patients treated with neutron boost after complete resection. After subtotal resection, the group that was treated with the higher neutron boost (7 Gy) showed a significant benefit in survival at twelve months. When patients had only a biopsy before irradiation, there was a benefit in survival after neutron boost, but no additional benefit was gained when the size of the neutron boost was increased from 6 to 7 Gy. (orig.) [de
Invariant distances and metrics in complex analysis
Jarnicki, Marek
2013-01-01
As in the field of ""Invariant Distances and Metrics in Complex Analysis"" there was and is a continuous progress this is the second extended edition of the corresponding monograph. This comprehensive book is about the study of invariant pseudodistances (non-negative functions on pairs of points) and pseudometrics (non-negative functions on the tangent bundle) in several complex variables. It is an overview over a highly active research area at the borderline between complex analysis, functional analysis and differential geometry. New chapters are covering the Wu, Bergman and several other met
The decomposition of global conformal invariants
Alexakis, Spyros
2012-01-01
This book addresses a basic question in differential geometry that was first considered by physicists Stanley Deser and Adam Schwimmer in 1993 in their study of conformal anomalies. The question concerns conformally invariant functionals on the space of Riemannian metrics over a given manifold. These functionals act on a metric by first constructing a Riemannian scalar out of it, and then integrating this scalar over the manifold. Suppose this integral remains invariant under conformal re-scalings of the underlying metric. What information can one then deduce about the Riemannian scalar? Dese
Application of invariant embedding to reactor physics
Shimizu, Akinao; Parsegian, V L
1972-01-01
Application of Invariant Embedding to Reactor Physics describes the application of the method of invariant embedding to radiation shielding and to criticality calculations of atomic reactors. The authors intend to show how this method has been applied to realistic problems, together with the results of applications which will be useful to shielding design. The book is organized into two parts. Part A deals with the reflection and transmission of gamma rays by slabs. The chapters in this section cover topics such as the reflection and transmission problem of gamma rays; formulation of the probl
Approaching Moons from Resonance via Invariant Manifolds
Anderson, Rodney L.
2012-01-01
In this work, the approach phase from the final resonance of the endgame scenario in a tour design is examined within the context of invariant manifolds. Previous analyses have typically solved this problem either by using numerical techniques or by computing a catalog of suitable trajectories. The invariant manifolds of a selected set of libration orbits and unstable resonant orbits are computed here to serve as guides for desirable approach trajectories. The analysis focuses on designing an approach phase that may be tied into the final resonance in the endgame sequence while also targeting desired conditions at the moon.
Conformal invariants topics in geometric function theory
Ahlfors, Lars V
2010-01-01
Most conformal invariants can be described in terms of extremal properties. Conformal invariants and extremal problems are therefore intimately linked and form together the central theme of this classic book which is primarily intended for students with approximately a year's background in complex variable theory. The book emphasizes the geometric approach as well as classical and semi-classical results which Lars Ahlfors felt every student of complex analysis should know before embarking on independent research. At the time of the book's original appearance, much of this material had never ap
Supersymmetric models with broken Lorentz invariance.
Directory of Open Access Journals (Sweden)
Marakulin Arthur
2017-01-01
Full Text Available Several supersymmetric theories with broken Lorentz invariance are considered. We study at the component level Lorentz violating representations of the supersymmetry algebra and construct Lagrangians for the scalar and vector supermultiplets with broken Lorentz invariance. Lorentz violating model for the gravitational supermultiplet is constructed using the superfield formalism as supersymmetric extension of the linearized Einstein-aether theory. The most general Lagrangian of the linearized Einstein-aether supergravity is constructed. We show that the Lagrangian for this model is unique and obtain its bosonic part in components. The constraints imposed by supersymmetry on the parameters of the theory are obtained. The phenomenological consequences of the model are discussed.
Perturbative string theory in BRST invariant formalism
International Nuclear Information System (INIS)
Di Vecchia, P.; Hornfeck, K.; Frau, M.; Lerda, A.
1988-01-01
In this talk we present a constructive and very explicit way of calculating multiloop amplitudes in string theories. The main ingredients are the BRST invariant N String Vertex and the BRST invariant twisted propagator. This approach naturally leads to the Schottky parametrization of moduli space in terms of multipliers and fixed points of the g projective transformations which characterize a Riemann surface of genus g. The complete expression (including measure) of the multiloop corrections to the N String Vertex for the bosonic string is exhibited. (orig.)
Lorentz invariance as a low energy phenomenon
International Nuclear Information System (INIS)
Chadha, S.
1982-09-01
It is propsed that the various symmetries observed in nature be regarded as infrared attractive fixed points of a large class of theories which are not endowed with these symmetries a priori. That this hypothesis is feasible is explicitly demonstrated for the case of Lorentz invariance. The strategy is to consider a suitable noncovariant model of electrodynamics, and to show by calculating the relevant β-functions that this model simulates Lorentz invariance better and better as the energy scale is progressively lowered. (Auth.)
Reparametrization invariance and the Schroedinger equation
International Nuclear Information System (INIS)
Tkach, V.I.; Pashnev, A.I.; Rosales, J.J.
1999-01-01
A time-dependent Schroedinger equation for systems invariant under the reparametrization of time is considered. We develop the two-stage procedure of construction such systems from a given initial ones, which are not invariant under the time reparametrization. One of the first-class constraints of the systems in such description becomes the time-dependent Schroedinger equation. The procedure is applicable in the supersymmetric theories as well. The n = 2 supersymmetric quantum mechanics is coupled to world-line supergravity, and the local supersymmetric action is constructed leading to the square root representation of the time-dependent Schroedinger equation
Quantized Hall conductance as a topological invariant
International Nuclear Information System (INIS)
Niu, Q.; Thouless, Ds.J.; Wu, Y.S.
1984-10-01
Whenever the Fermi level lies in a gap (or mobility gap) the bulk Hall conductance can be expressed in a topologically invariant form showing the quantization explicitly. The new formulation generalizes the earlier result by TKNN to the situation where many body interaction and substrate disorder are also present. When applying to the fractional quantized Hall effect we draw the conclusion that there must be a symmetry breaking in the many body ground state. The possibility of writing the fractionally quantized Hall conductance as a topological invariant is also carefully discussed. 19 references
Scaling theory of {{{Z}}_{2}} topological invariants
Chen, Wei; Sigrist, Manfred; Schnyder, Andreas P.
2016-09-01
For inversion-symmetric topological insulators and superconductors characterized by {{{Z}}2} topological invariants, two scaling schemes are proposed to judge topological phase transitions driven by an energy parameter. The scaling schemes renormalize either the phase gradient or the second derivative of the Pfaffian of the time-reversal operator, through which the renormalization group flow of the driving energy parameter can be obtained. The Pfaffian near the time-reversal invariant momentum is revealed to display a universal critical behavior for a great variety of models examined.
Modeling laser wakefield accelerators in a Lorentz boosted frame
Energy Technology Data Exchange (ETDEWEB)
Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grote, D.P.
2010-09-15
Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [1] is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing theframe of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two orders of magnitude for a 0.1 GeV class stages. The method then allows direct and efficient full-scale modeling of deeply depleted laser-plasma stages of 10 GeV-1 TeV for the first time, verifying the scaling of plasma accelerators to very high energies. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively.
Modeling laser wakefield accelerators in a Lorentz boosted frame
Energy Technology Data Exchange (ETDEWEB)
Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grotec, D. P.
2010-06-15
Modeling of laser-plasma wakefield accelerators in an optimal frame of reference is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high-frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing the frame of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two orders of magnitude for a 0.1 GeV class stages. The method then allows direct and efficient full-scale modeling of deeply depleted laser-plasma stages of 10 GeV-1 TeV for the first time, verifying the scaling of plasma accelerators to very high energies. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively.
Invariant of dynamical systems: A generalized entropy
International Nuclear Information System (INIS)
Meson, A.M.; Vericat, F.
1996-01-01
In this work the concept of entropy of a dynamical system, as given by Kolmogorov, is generalized in the sense of Tsallis. It is shown that this entropy is an isomorphism invariant, being complete for Bernoulli schemes. copyright 1996 American Institute of Physics
Field transformations, collective coordinates and BRST invariance
International Nuclear Information System (INIS)
Alfaro, J.; Damgaard, P.H.
1989-12-01
A very large class of general field transformations can be viewed as a field theory generalization of the method of collective coordinates. The introduction of new variables induces a gauge invariance in the transformed theory, and the freedom left in gauge fixing this new invariance can be used to find equivalent formulations of the same theory. First the Batalin-Fradkin-Vilkovisky formalism is applied to the Hamiltonian formulation of physical systems that can be described in terms of collective coordinates. We then show how this type of collective coordinate scheme can be generalized to field transformations, and discuss the War Identities of the associated BRST invariance. For Yang-Mills theory a connection to topological field theory and the background field method is explained in detail. In general the resulting BRST invariance we find hidden in any quantum field theory can be viewed as a consequence of our freedom in choosing a basis of coordinates φ(χ) in the action S[φ]. (orig.)
Learning the Lie groups of visual invariance.
Miao, Xu; Rao, Rajesh P N
2007-10-01
A fundamental problem in biological and machine vision is visual invariance: How are objects perceived to be the same despite transformations such as translations, rotations, and scaling? In this letter, we describe a new, unsupervised approach to learning invariances based on Lie group theory. Unlike traditional approaches that sacrifice information about transformations to achieve invariance, the Lie group approach explicitly models the effects of transformations in images. As a result, estimates of transformations are available for other purposes, such as pose estimation and visuomotor control. Previous approaches based on first-order Taylor series expansions of images can be regarded as special cases of the Lie group approach, which utilizes a matrix-exponential-based generative model of images and can handle arbitrarily large transformations. We present an unsupervised expectation-maximization algorithm for learning Lie transformation operators directly from image data containing examples of transformations. Our experimental results show that the Lie operators learned by the algorithm from an artificial data set containing six types of affine transformations closely match the analytically predicted affine operators. We then demonstrate that the algorithm can also recover novel transformation operators from natural image sequences. We conclude by showing that the learned operators can be used to both generate and estimate transformations in images, thereby providing a basis for achieving visual invariance.
Gauge invariance and fractional quantized Hall effect
International Nuclear Information System (INIS)
Tao, R.; Wu, Y.S.
1984-01-01
It is shown that gauge invariance arguments imply the possibility of fractional quantized Hall effect; the Hall conductance is accurately quantized to a rational value. The ground state of a system showing the fractional quantized Hall effect must be degenerate; the non-degenerate ground state can only produce the integral quantized Hall effect. 12 references
Invariant metric for nonlinear symplectic maps
Indian Academy of Sciences (India)
a function of system parameters, we demonstrate that the performance of a nonlinear Hamiltonian system is enhanced. Keywords. Invariant metric; symplectic maps; performance optimization. PACS Nos 05.45. ...... [7] A Nijenhuis and H S Wilf, Computational algorithms for computers and calculators (Academic. Press, New ...
Neutrinos as Probes of Lorentz Invariance
Directory of Open Access Journals (Sweden)
Jorge S. Díaz
2014-01-01
Full Text Available Neutrinos can be used to search for deviations from exact Lorentz invariance. The worldwide experimental program in neutrino physics makes these particles a remarkable tool to search for a variety of signals that could reveal minute relativity violations. This paper reviews the generic experimental signatures of the breakdown of Lorentz symmetry in the neutrino sector.
Testing Lorentz and CPT Invariance with Neutrinos
Directory of Open Access Journals (Sweden)
Jorge S. Díaz
2016-10-01
Full Text Available Neutrino experiments can be considered sensitive tools to test Lorentz and CPT invariance. Taking advantage of the great variety of neutrino experiments, including neutrino oscillations, weak decays, and astrophysical neutrinos, the generic experimental signatures of the breakdown of these fundamental symmetries in the neutrino sector are presented.
Automatic invariant detection in dynamic web applications
Groeneveld, F.; Mesbah, A.; Van Deursen, A.
2010-01-01
The complexity of modern web applications increases as client-side JavaScript and dynamic DOM programming are used to offer a more interactive web experience. In this paper, we focus on improving the dependability of such applications by automatically inferring invariants from the client-side and
Constitutive laws, tensorial invariance and chocolate cake
Rundle, John B.; Passman, S. L.
1982-04-01
Although constitutive modeling is a well-established branch of mathematics which has found wide industrial application, geophysicists often do not take full advantage of its known results. We present a synopsis of the theory of constitutive modeling, couched in terms of the ‘simple material’, which has been extensively studied and is complex enough to include most of the correct models proposed to describe the behavior of geological materials. Critical in the development of the theory are various invariance requirements, the principal ones being coordinate invariance, peer group invariance (isotropy), and frame-indifference. Each places distinet restrictions on constitutive equations. A noncomprehensive list of properly invariant and commonly used constitutive equations is given. To exemplify use of the equations, we consider two problems in detail: steady extension, which models the commonly performed constant strain rate triaxial test, and simple shearing. We note that each test is so restricted kinematically that only the most trivial aspects of material behavior are manifested in these tests, no matter how complex the material. Furthermore, the results of one test do not generally determine the results of the other.
Invariant metric for nonlinear symplectic maps
Indian Academy of Sciences (India)
In this paper, we construct an invariant metric in the space of homogeneous polynomials of a given degree (≥ 3). The homogeneous polynomials specify a nonlinear symplectic map which in turn represents a Hamiltonian system. By minimizing the norm constructed out of this metric as a function of system parameters, we ...
Joint local quasinilpotence and common invariant subspaces
Indian Academy of Sciences (India)
MS received 27 November 2005; revised 3 February 2006. Abstract. In this article we obtain some positive results about the existence of a common nontrivial invariant subspace for N-tuples of not necessarily commuting operators on. Banach spaces with a Schauder basis. The concept of joint quasinilpotence plays a basic.
Notes on the knot concordance invariant Upsilon
Livingston, Charles
2014-01-01
The knot concordance invariant Upsilon, recently defined by Ozsvath, Stipsicz, and Szabo, takes values in the group of piecewise linear functions on the closed interval [0,2]. This paper presents a description of one approach to defining Upsilon and of proving its basic properties related to the knot 3-genus, 4-genus, and concordance genus.
General relativity invariance and string field theory
International Nuclear Information System (INIS)
Aref'eva, I.Ya.; Volovich, I.V.
1987-04-01
The general covariance principle in the string field theory is considered. The algebraic properties of the string Lie derivative are discussed. The string vielbein and spin connection are introduced and an action invariant under general co-ordinate transformation is proposed. (author). 18 refs
Translationally invariant self-consistent field theories
International Nuclear Information System (INIS)
Shakin, C.M.; Weiss, M.S.
1977-01-01
We present a self-consistent field theory which is translationally invariant. The equations obtained go over to the usual Hartree-Fock equations in the limit of large particle number. In addition to deriving the dynamic equations for the self-consistent amplitudes we discuss the calculation of form factors and various other observables
Adaptivity and group invariance in mathematical morphology
Roerdink, Jos B.T.M.
2009-01-01
The standard morphological operators are (i) defined on Euclidean space, (ii) based on structuring elements, and (iii) invariant with respect to translation. There are several ways to generalise this. One way is to make the operators adaptive by letting the size or shape of structuring elements
Superfield approach to symmetry invariance in quantum ...
Indian Academy of Sciences (India)
vectors Ei and Bi are the electric and magnetic fields and totally antisymmetric εijk is the 3D Levi–Civita tensor. ... origin to the exterior derivative (i.e. d = dxµ∂µ) of the differential geometry, remains invariant. ... of the Langrangian density (2.1), modulo some total ordinary space-time derivative terms, which do not affect the ...
Real object recognition using moment invariants
Indian Academy of Sciences (India)
associative memory was used to create a system, recognizing objects regardless of changes in rotation or scale by Wechsler & Zimmerman (1998) 3-D object simulations were ..... Hu M 1962 Visual pattern recognition by moment invariants. IRE Trans. Inf. Theor. IT-8: 179–187. Khotanzad A, Lu J-H 1990 Classification of ...
Invariant properties between stroke features in handwriting
Teulings, H L; Schomaker, L R
A handwriting pattern is considered as a sequence of ballistic strokes. Replications of a pattern may be generated from a single, higher-level memory representation, acting as a motor program. Therefore, those stroke features which show the most invariant pattern are probably related to the
Invariant Theory (IT) & Standard Monomial Theory (SMT)
Indian Academy of Sciences (India)
2013-07-06
Jul 6, 2013 ... Introducing co-ordinate axes in the usual fashion (with origin at the central point), we can represent the points by ordered pairs (xred, yred), (xblue, yblue), (xgreen, ygreen),. (xyellow, yyellow). ..... What are the (polynomial) invariants in this case? The dot products x2 red + y2 red, . . . (of every point with itself) ...
Conformal branching rules and modular invariants
International Nuclear Information System (INIS)
Walton, M.A.
1989-01-01
Using the outer automorphisms of the affine algebra SU(n), we show how the branching rules for the conformal subalgebra SU(pq) contains SU(p) x SU(q) may be simply calculated. We demonstrate that new modular invariant combinations of SU(n) characters are obtainable from the branching rules. (orig.)
Dimensional analysis using toric ideals: primitive invariants.
Directory of Open Access Journals (Sweden)
Mark A Atherton
Full Text Available Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units [Formula: see text] etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer [Formula: see text] matrix from the initial integer [Formula: see text] matrix holding the exponents for the derived quantities. The [Formula: see text] matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups is obtained directly from the toric ideal defined by [Formula: see text]. One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of [Formula: see text], is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found.
Boosted cylindrical magnetized Kaluza-Klein wormhole
Hashemi, S. Sedigheh; Riazi, Nematollah
2018-02-01
In this work, we consider a vacuum solution of Kaluza-Klein theory with cylindrical symmetry. We investigate the physical properties of the solution as viewed in four dimensional spacetime, which turns out to be a stationary, cylindrical wormhole supported by a scalar field and a magnetic field oriented along the wormhole. We then apply a boost to the five dimensional solution along the extra dimension, and perform the Kaluza-Klein reduction. As a result, we show that the new solution is still a wormhole with a radial electric field and a magnetic field stretched along the wormhole throat.
single-phase dc phase dc-ac boost converter ac boost converter
African Journals Online (AJOL)
User
supply (UPS) AC motor drives and other power sup systems, need to step-up the DC input voltage. increase the output voltage level in order requirements, DC-DC boost converter is used provide DC bus voltage for PWM inverters. Hence, conventional design always cascades DC and a separate DC-AC converter.
Aichelburg-Sexl boost of domain walls and cosmic strings
International Nuclear Information System (INIS)
Barrabes, C.; Hogan, P.A.; Israel, W.
2002-01-01
We consider the application of the Aichelburg-Sexl boost to plane and line distributions of matter. Our analysis shows that for a domain wall the space-time after the boost is flat except on a null hypersurface which is the history of a null shell. For a cosmic string we study the influence of the boost on the conical singularity and give the new value of the conical deficit
Inelastic Boosted Dark Matter at direct detection experiments
Giudice, Gian F.; Kim, Doojin; Park, Jong-Chul; Shin, Seodong
2018-01-01
We explore a novel class of multi-particle dark sectors, called Inelastic Boosted Dark Matter (iBDM). These models are constructed by combining properties of particles that scatter off matter by making transitions to heavier states (Inelastic Dark Matter) with properties of particles that are produced with a large Lorentz boost in annihilation processes in the galactic halo (Boosted Dark Matter). This combination leads to new signals that can be observed at ordinary direct detection experimen...
Quantization of a conformal invariant pure spinor model
International Nuclear Information System (INIS)
Akdeniz, K.G.; Hortacsu, M.; Pak, N.K.; Arik, M.
1982-08-01
The Gursey model, a conformally invariant pure spinor model in four dimensions, is shown to yield a renormalizable field theory, which is asymptotically free in the phase which has discrete ν 5 -invariance. (author)
Boosted Higgs boson tagging using jet substructures
Shvydkin, Pavel
2016-01-01
Searching BSM particles via the Higgs boson final state has now become common. The mass of desired BSM particle is more than 1 TeV, thereby its decay products are highly Lorentz-boosted. Hence the jets from b quark-antiquark pair - which the Higgs boson mostly decays into - are very closed to each other, and merged into one jet, that is typically reconstructed using large jet sizes (∆R = 0.8). In this work regression technique is applied to AK8 jets (which defined by anti-kT algorithm, using ΔR = 0.8). The regression makes use of boosted jets with substructure information, coupled with the pecularities of a b quark decay, like the presence of a soft lepton (SL) inside the jet. It has allowed to improve the resolution of the mass reconstruction and transverse momentum of the Higgs boson. This application results in improvement of the mass reconstruction by 3-4 percent. These result may be improved firstly by making more careful pileup rejection. Then it is possible to combine base regression train for dif...
A scale invariant covariance structure on jet space
DEFF Research Database (Denmark)
Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo
2005-01-01
This paper considers scale invariance of statistical image models. We study statistical scale invariance of the covariance structure of jet space under scale space blurring and derive the necessary structure and conditions of the jet covariance matrix in order for it to be scale invariant. As part...... results where we estimate the scale invariant jet covariance of natural images and show that it resembles that of Brownian images....
How to Find Invariants for Coloured Petri Nets
DEFF Research Database (Denmark)
Jensen, Kurt
1981-01-01
This paper shows how invariants can be found for coloured Petri Nets. We define a set of transformation rules, which can be used to transform the incidence matrix, without changing the set of invariants.......This paper shows how invariants can be found for coloured Petri Nets. We define a set of transformation rules, which can be used to transform the incidence matrix, without changing the set of invariants....
The gauge invariant Lagrangian for Seiberg-Witten topological monopoles
International Nuclear Information System (INIS)
Gianvittorio, R.; Martin, I.; Restuccia, A.
1995-04-01
A topological gauge invariant Lagrangian for Seiberg-Witten monopole equations is constructed. The actions is invariant under a huge class of gauge transformations which after BRST fixing leads to the BRST invariant actin associated to Seiberg-Witten monopole topological theory. The supersymmetric transformation of the fields involved in the construction is obtained from the nilpotent BRST algebra. (author). 6 refs
Complex dynamical invariants for two-dimensional complex potentials
Indian Academy of Sciences (India)
that the cubic oscillator and shifted harmonic oscillator admit quadratic complex invariants. The obtained invariants ..... where α, β, α1,α2,β1,β2,δ3 and δ4 are arbitrary constants of integration. Pramana – J. Phys. ..... An invariant for a shifted harmonic oscillator in complex plane can be derived by substi- tuting δ3 = 0,δ2 = −1.
Invariant Einstein metrics on Ledger-Obata spaces
Chen, Zhiqi; Nikonorov, Yuriĭ; Nikonorova, Yulia
2016-01-01
In this paper, we study invariant Einstein metrics on Ledger-Obata spaces $F^m/\\operatorname{diag}(F)$. In particular, we classify invariant Einstein metrics on $F^4/\\operatorname{diag}(F)$ and estimate the number of invariant Einstein metrics on general Ledger-Obata spaces $F^{m}/\\operatorname{diag}(F)$.
Image indexing using composite color and shape invariant features
Gevers, Th.; Smeulders, A.W.M.
1998-01-01
New sets of color models are proposed for object recognition invariant to a change in view point, object geometry and illumination. Further, computational methods are presented to combine color and shape invariants to produce a high-dimensional invariant feature set for discriminatory object
The need for invariant assessments in South African education
African Journals Online (AJOL)
Even though we cannot conclude at this stage that the Marko-D satisfies the requirements of invariance and unidimensionality com- pletely, this study provides an elucidation of the need for invariant assessments in South African education. Keywords: foundation phase learners; invariance; mathematical competence; ...
The geometric Hopf invariant and surgery theory
Crabb, Michael
2017-01-01
Written by leading experts in the field, this monograph provides homotopy theoretic foundations for surgery theory on higher-dimensional manifolds. Presenting classical ideas in a modern framework, the authors carefully highlight how their results relate to (and generalize) existing results in the literature. The central result of the book expresses algebraic surgery theory in terms of the geometric Hopf invariant, a construction in stable homotopy theory which captures the double points of immersions. Many illustrative examples and applications of the abstract results are included in the book, making it of wide interest to topologists. Serving as a valuable reference, this work is aimed at graduate students and researchers interested in understanding how the algebraic and geometric topology fit together in the surgery theory of manifolds. It is the only book providing such a wide-ranging historical approach to the Hopf invariant, double points and surgery theory, with many results old and new. .
Scale invariance from phase transitions to turbulence
Lesne, Annick
2012-01-01
During a century, from the Van der Waals mean field description (1874) of gases to the introduction of renormalization group (RG techniques 1970), thermodynamics and statistical physics were just unable to account for the incredible universality which was observed in numerous critical phenomena. The great success of RG techniques is not only to solve perfectly this challenge of critical behaviour in thermal transitions but to introduce extremely useful tools in a wide field of daily situations where a system exhibits scale invariance. The introduction of scaling, scale invariance and universality concepts has been a significant turn in modern physics and more generally in natural sciences. Since then, a new "physics of scaling laws and critical exponents", rooted in scaling approaches, allows quantitative descriptions of numerous phenomena, ranging from phase transitions to earthquakes, polymer conformations, heartbeat rhythm, diffusion, interface growth and roughening, DNA sequence, dynamical systems, chaos ...
Odor concentration invariance by chemical ratio coding
Directory of Open Access Journals (Sweden)
Naoshige Uchida
2008-08-01
Full Text Available Many animal species rely on chemical signals to extract ecologically important information from the environment. Yet in natural conditions chemical signals will frequently undergo concentration changes that produce differences in both level and pattern of activation of olfactory receptor neurons. Thus, a central problem in olfactory processing is how the system is able to recognize the same stimulus across different concentrations. To signal species identity for mate recognition, some insects use the ratio of two components in a binary chemical mixture to produce a code that is invariant to dilution. Here, using psychophysical methods, we show that rats also classify binary odor mixtures according to the molar ratios of their components, spontaneously generalizing over at least a tenfold concentration range. These results indicate that extracting chemical ratio information is not restricted to pheromone signaling and suggest a general solution for concentration-invariant odor recognition by the mammalian olfactory system.
Mutation, Witten index, and quiver invariant
International Nuclear Information System (INIS)
Kim, Heeyeon; Lee, Seung-Joo; Yi, Piljin
2015-01-01
We explore Seiberg-like dualities, or mutations, for N=4 quiver quantum mechanics in the context of wall-crossing. In contrast to higher dimensions, the 1d Seiberg-duality must be performed with much care. With fixed Fayet-Iliopoulos constants, at most two nodes can be mutated, one left and the other right, mapping a chamber of a quiver into a chamber of a mutated quiver. We delineate this complex pattern for triangle quivers and show how the Witten indices are preserved under such finely chosen mutations. On the other hand, the quiver invariants, or wall-crossing-safe part of supersymmetric spectra, mutate more straightforwardly, whereby a quiver is mapped to a quiver. The mutation rule that preserves the quiver invariant is different from the usual one, however, which we explore and confirm numerically.
BRS invariant stochastic quantization of Einstein gravity
International Nuclear Information System (INIS)
Nakazawa, Naohito.
1989-11-01
We study stochastic quantization of gravity in terms of a BRS invariant canonical operator formalism. By introducing artificially canonical momentum variables for the original field variables, a canonical formulation of stochastic quantization is proposed in the sense that the Fokker-Planck hamiltonian is the generator of the fictitious time translation. Then we show that there exists a nilpotent BRS symmetry in an enlarged phase space of the first-class constrained systems. The phase space is spanned by the dynamical variables, their canonical conjugate momentum variables, Faddeev-Popov ghost and anti-ghost. We apply the general BRS invariant formulation to stochastic quantization of gravity which is described as a second-class constrained system in terms of a pair of Langevin equations coupled with white noises. It is shown that the stochastic action of gravity includes explicitly the De Witt's type superspace metric which leads to a geometrical interpretation of quantum gravity analogous to nonlinear σ-models. (author)
Role of Lifshitz Invariants in Liquid Crystals
Directory of Open Access Journals (Sweden)
Amelia Sparavigna
2009-06-01
Full Text Available The interaction between an external action and the order parameter, via a dependence described by a so-called Lifshitz invariant, is very important to determine the final configuration of liquid crystal cells. The external action can be an electric field applied to the bulk or the confinement due to free surfaces or cell walls. The Lifshitz invariant includes the order parameter in the form of an elastic strain. This coupling between elastic strains and fields, inserted in a Landau-Ginzburg formalism, is well known and gives rise to striction effects causing undulations in the director configuration. We want to discuss here the role of Lifshitz coupling terms, following an approach similar to that introduced by Dzyaloshinskii for magnetic materials. Case studies on nematics in planar and cylindrical cells are also proposed.
CP invariance: a point of view
International Nuclear Information System (INIS)
Mohan, Gyan
1983-01-01
That the longlived component L of K 0 has both CP = +1 and CP = -1 modes of decay is often cited as evidence of violation of CP invariance. The careful ones find the compelling evidence to be the non-dilution of the regeneration interference pattern when the incident K 0 beam is mixed even substantially with anti-K 0 . However the two phenomena comprehensively imply that L has a CP = +1 component Lsub(+) and CP = -1 component Lsub(-) and that the longlived component of both K 0 and anti-K 0 are one and the same L. This does not demand abandoning CP invariance. It does imply that anti-K 0 is not the CP conjugate of K 0 . (author)
Gauge-invariant variables and entanglement entropy
Agarwal, Abhishek; Karabali, Dimitra; Nair, V. P.
2017-12-01
The entanglement entropy (EE) of gauge theories in three spacetime dimensions is analyzed using manifestly gauge-invariant variables defined directly in the continuum. Specifically, we focus on the Maxwell, Maxwell-Chern-Simons (MCS), and non-Abelian Yang-Mills theories. Special attention is paid to the analysis of edge modes and their contribution to EE. The contact term is derived without invoking the replica method and its physical origin is traced to the phase space volume measure for the edge modes. The topological contribution to the EE for the MCS case is calculated. For all the Abelian cases, the EE presented in this paper agrees with known results in the literature. The EE for the non-Abelian theory is computed in a gauge-invariant Gaussian approximation, which incorporates the dynamically generated mass gap. A formulation of the contact term for the non-Abelian case is also presented.
Revisiting R-invariant direct gauge mediation
Energy Technology Data Exchange (ETDEWEB)
Chiang, Cheng-Wei [Center for Mathematics and Theoretical Physics andDepartment of Physics, National Central University,Taoyuan, Taiwan 32001, R.O.C. (China); Institute of Physics, Academia Sinica,Taipei, Taiwan 11529, R.O.C. (China); Physics Division, National Center for Theoretical Sciences,Hsinchu, Taiwan 30013, R.O.C. (China); Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Ibe, Masahiro [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Yanagida, Tsutomu T. [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)
2016-03-21
We revisit a special model of gauge mediated supersymmetry breaking, the “R-invariant direct gauge mediation.” We pay particular attention to whether the model is consistent with the minimal model of the μ-term, i.e., a simple mass term of the Higgs doublets in the superpotential. Although the incompatibility is highlighted in view of the current experimental constraints on the superparticle masses and the observed Higgs boson mass, the minimal μ-term can be consistent with the R-invariant gauge mediation model via a careful choice of model parameters. We derive an upper limit on the gluino mass from the observed Higgs boson mass. We also discuss whether the model can explain the 3σ excess of the Z+jets+E{sub T}{sup miss} events reported by the ATLAS collaboration.
Monopoles, Abelian projection, and gauge invariance
International Nuclear Information System (INIS)
Bonati, Claudio; Di Giacomo, Adriano; Lepori, Luca; Pucci, Fabrizio
2010-01-01
A direct connection is proved between the non-Abelian Bianchi Identities (NABI's) and the Abelian Bianchi identities for the 't Hooft tensor. As a consequence, the existence of a nonzero magnetic current is related to the violation of the NABI's and is a gauge-invariant property. The construction allows us to show that not all Abelian projections can be used to expose monopoles in lattice configurations: each field configuration with nonzero magnetic charge identifies its natural projection, up to gauge transformations which tend to unity at large distances. It is shown that the so-called maximal-Abelian gauge is a legitimate choice. It is also proven, starting from the NABI, that monopole condensation is a physical gauge-invariant phenomenon, independent of the choice of the Abelian projection.
Adiabatic invariants for field-reversed configurations
International Nuclear Information System (INIS)
Schwarzmeier, J.L.; Lewis, H.R.; Seyler, C.E.
1982-01-01
Field reversed configurations (FRCs) are characterized by azimuthal symmetry, so two exact constants of the particle motion are the total particle energy E and the canonical angular momentum P/sub theta/. For many purposes it is desirable to construct a third (diabatic) constant of the motion if this is possible. It is shown that for parameters characteristic of current FRCs that the magnetic moment μ is a poor adiabatic invariant, while the radial action J is conserved rather well
Liaison, Schottky Problem and Invariant Theory
Alonso, Maria Emilia; Mallavibarrena, Raquel; Sols, Ignacio
2010-01-01
This volume is a homage to the memory of the Spanish mathematician Federico Gaeta (1923-2007). Apart from a historical presentation of his life and interaction with the classical Italian school of algebraic geometry, the volume presents surveys and original research papers on the mathematics he studied. Specifically, it is divided into three parts: linkage theory, Schottky problem and invariant theory. On this last topic a hitherto unpublished article by Federico Gaeta is also included.
3D rotation invariants by complex moments
Czech Academy of Sciences Publication Activity Database
Suk, Tomáš; Flusser, Jan; Boldyš, Jiří
2015-01-01
Roč. 48, č. 11 (2015), s. 3516-3526 ISSN 0031-3203 R&D Projects: GA ČR(CZ) GA13-29225S; GA ČR(CZ) GA15-16928S Institutional support: RVO:67985556 Keywords : Complex moment * spherical harmonic * group representation theory * 3D rotation invariant Subject RIV: IN - Informatics, Computer Science Impact factor: 3.399, year: 2015 http://library.utia.cas.cz/separaty/2015/ZOI/suk-0445882.pdf
Invariant dependence structures and Archimedean copulas
Czech Academy of Sciences Publication Activity Database
Durante, F.; Jaworski, P.; Mesiar, Radko
2011-01-01
Roč. 81, č. 12 (2011), s. 1995-2003 ISSN 0167-7152 R&D Projects: GA ČR GAP402/11/0378 Institutional research plan: CEZ:AV0Z10750506 Keywords : Archimedean copula * Tail dependence * Clayton model Subject RIV: BA - General Mathematics Impact factor: 0.498, year: 2011 http://library.utia.cas.cz/separaty/2011/E/mesiar-invariant dependence structures and archimedean copulas.pdf
Coordinate invariant conservation laws in Schwarzschild geometry
Energy Technology Data Exchange (ETDEWEB)
Burghardt, R.
1983-01-01
Einstein's field equations can be written in a special way to give expressions free of any quantities which cannot be measured. These expressions are fully coordinate invariant but observer dependent. Generalized Lorentz transformations according to Treder's theory serve as connecting links between the measured values of different observer systems. The field equations contain expressions for gravitational energy stresses which satisfy covariant conservation laws.
Affine Moment Invariants Generated by Graph Method
Czech Academy of Sciences Publication Activity Database
Suk, Tomáš; Flusser, Jan
2011-01-01
Roč. 44, č. 9 (2011), 2047 – 2056 ISSN 0031-3203 R&D Projects: GA ČR(CZ) GA102/08/1593 Institutional research plan: CEZ:AV0Z10750506 Keywords : Image moments * Object recognition * Affine transformation * Affine moment invariants * Pseudoinvariants * Graph representation * Irreducibility * Independence Subject RIV: IN - Informatics, Computer Science Impact factor: 2.292, year: 2011 http://library.utia.cas.cz/separaty/2011/ZOI/suk-0359752.pdf
Invariance and inconsistency in utility ratings.
Bravata, Dena M; Nelson, Lorene M; Garber, Alan M; Goldstein, Mary K
2005-01-01
To assess utilities of composite health states for dependence in activities of daily living (ADLs) for invariance (i.e., when subjects provide a utility of 1 for all health states) and order inconsistency (i.e., when subjects order their utilities such that their utility for a combination of ADL dependencies is greater than their utility for any subset of the combination). Each of the 400 subjects, age 65 y and older, enrolled in one of several regional medical centers of the Kaiser Permanente Medical Care Program of Northern California and provided standard-gamble utilities for single ADL dependencies (e.g., bathing, dressing, continence) and for dependence in 8 other combinations of ADL dependencies. For order-inconsistent responses, the authors calculated the maximum magnitude of inconsistency as the maximum difference between the utility for the combined ADL dependence health state and that of its inconsistent subset. A total of 76 subjects (19%) gave a utility of 1.0 for all health states presented to them; 19 (5%) gave the same utility other than 1.0 for all health states; 130 (33%) gave at least 1 utility Invariance was associated with a Mini-Mental Status Examination score invariant (0.88 [0.24]) was higher than among inconsistent subjects (0.80 [0.27]; P = 0.01). Invariance and order inconsistencies in utility ratings for complex health states occur frequently. Utilities of consistent subjects may differ from those of inconsistent subjects. Utility assessments should attempt to measure and report these patterns.
Visual Distinctness Determined by Partially Invariant Features
2000-03-01
DISTINCTNESS DETERMINED BY PARTIALLY INVARIANT FEATURES. J.A. Garcia, J. Fdez-Valdivia Departamento de Ciencias de la Computacion e I.A. Univ. de Granada...constant, independently of the viewing distance.The perceptual organization capabilities of human in a complex rural background. vision seem to exhibit...designed and 5.1.2. Clarity of separation at stage j organized by NVESD (Night Vision & Electro-optic Sensors Here we introduce the criterion by which we
O(3)-invariant tunneling in general relativity
International Nuclear Information System (INIS)
Berezin, V.A.; Tkachev, I.I.; Kuzmin, V.A.; AN SSSR, Moscow. Inst. Yadernykh Issledovanij)
1987-12-01
We derived a general formula for the action for any O(3)-invariant tunneling processes in false vacuum decay in general relativity. The general classification of the bubble Euclidean trajectories is elaborated and explicit expressions for bounces for some processes like the vacuum creation of a double bubble, in particular in the vicinity of a black hole; the subbarrier creation of the Einstein-Rosen bridge, creation from nothing of two Minkowski worlds connected by a shell etc., are given. (orig.)
On local invariants of singular symplectic forms
Domitrz, Wojciech
2017-04-01
We find a complete set of local invariants of singular symplectic forms with the structurally stable Martinet hypersurface on a 2 n-dimensional manifold. In the C-analytic category this set consists of the Martinet hypersurface Σ2, the restriction of the singular symplectic form ω to TΣ2 and the kernel of ω n - 1 at the point p ∈Σ2. In the R-analytic and smooth categories this set contains one more invariant: the canonical orientation of Σ2. We find the conditions to determine the kernel of ω n - 1 at p by the other invariants. In dimension 4 we find sufficient conditions to determine the equivalence class of a singular symplectic form-germ with the structurally smooth Martinet hypersurface by the Martinet hypersurface and the restriction of the singular symplectic form to it. We also study the singular symplectic forms with singular Martinet hypersurfaces. We prove that the equivalence class of such singular symplectic form-germ is determined by the Martinet hypersurface, the canonical orientation of its regular part and the restriction of the singular symplectic form to its regular part if the Martinet hypersurface is a quasi-homogeneous hypersurface with an isolated singularity.
Representation of magnetic fields with toroidal topology in terms of field-line invariants
International Nuclear Information System (INIS)
Lewis, H.R.
1990-01-01
Beginning with Boozer's representation of magnetic fields with toroidal topology [Phys. Fluids 26, 1288 (1983)], a general formalism is presented for the representation of any magnetic field with toroidal topology in terms of field-line invariants. The formalism is an application to the magnetic field case of results developed recently by Lewis et al. (submitted for publication to J. Phys. A) for arbitrary time-dependent Hamiltonian systems with one degree of freedom. Every magnetic field with toroidal topology can be associated with time-dependent Hamiltonian systems with one degree of freedom and every time-dependent Hamiltonian system with one degree of freedom can be associated with magnetic fields with toroidal topology. In the Hamiltonian context, given any particular function I(q,p,t), Lewis et al. derived those Hamiltonians for which I(q,p,t) is an invariant. In addition, for each of those Hamiltonians, they derived a function canonically conjugate to I(q,p,t) that is also an invariant. They applied this result to the case where I(q,p,t) is expressed as a function of two canonically conjugate functions. This general Hamiltonian formalism provides a basis for representing magnetic fields with toroidal topology in terms of field-line invariants. The magnetic fields usually contain plasma with flow and anisotropic pressure. A class of fields with or without rotational symmetry is identified for which there are magnetic surfaces. The formalism is developed for application to the case of vacuum magnetic fields
The maximal kinematical invariance group of fluid dynamics and explosion-implosion duality
International Nuclear Information System (INIS)
O'Raifeartaigh, L.; Sreedhar, V.V.
2001-01-01
It has recently been found that supernova explosions can be simulated in the laboratory by implosions induced in a plasma by intense lasers. A theoretical explanation is that the inversion transformation, (Σ:t→-1/t, x→x/t), leaves the Euler equations of fluid dynamics, with standard polytropic exponent, invariant. This implies that the kinematical invariance group of the Euler equations is larger than the Galilei group. In this paper we determine, in a systematic manner, the maximal invariance group G of general fluid dynamics and show that it is a semi-direct product G=SL(2, R) three G, where the SL(2, R) group contains the time-translations, dilations, and the inversion Σ, and G is the static (nine-parameter) Galilei group. A subtle aspect of the inclusion of viscosity fields is discussed and it is shown that the Navier-Stokes assumption of constant viscosity breaks the SL(2, R) group to a two-parameter group of time translations and dilations in a tensorial way. The 12-parameter group G is also known to be the maximal invariance group of the free Schroedinger equation. It originates in the free Hamilton-Jacobi equation which is central to both fluid dynamics and the Schroedinger equation
Very boosted Higgs in gluon fusion
Grojean, Christophe; Schlaffer, Matthias; Weiler, Andreas
2014-01-01
The Higgs production and decay rates offer a new way to probe new physics beyond the Standard Model. While dynamics aiming at alleviating the hierarchy problem generically predict deviations in the Higgs rates, the current experimental analyses cannot resolve the long- and short-distance contributions to the gluon fusion process and thus cannot access directly the coupling between the Higgs and the top quark. We investigate the production of a boosted Higgs in association with a high-transverse momentum jet as an alternative to the $t\\bar{t}h$ channel to pin down this crucial coupling. Presented first in the context of an effective field theory, our analysis is then applied to models of partial compositeness at the TeV scale and of natural supersymmetry.
Giving top quark effective operators a boost
Englert, Christoph
2016-01-01
We investigate the prospects to systematically improve generic effective field theory-based searches for new physics in the top sector during LHC run 2 as well as the high luminosity phase. In particular, we assess the benefits of high momentum transfer final states on top EFT-fit as a function of systematic uncertainties in comparison with sensitivity expected from fully-resolved analyses focusing on $t\\bar t$ production. We find that constraints are typically driven by fully-resolved selections, while boosted top quarks can serve to break degeneracies in the global fit. This demystifies and clarifies the importance of high momentum transfer final states for global fits to new interactions in the top sector from direct measurements.
Very boosted Higgs in gluon fusion
Energy Technology Data Exchange (ETDEWEB)
Grojean, C. [Univ. Autonoma de Barcelona, Bellaterra (Spain). ICREA at IFAE; Salvioni, E. [California Univ., Davis, CA (United States). Dept. of Physics; European Organization for Nuclear Research (CERN), Geneva (Switzerland); Padova Univ. (Italy). Dipt. di Fisica e Astronomica; INFN, Sezione di Padova (Italy); Schlaffer, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Weiler, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2013-12-15
The Higgs production and decay rates offer a new way to probe new physics beyond the Standard Model. While dynamics aiming at alleviating the hierarchy problem generically predict deviations in the Higgs rates, the current experimental analyses cannot resolve the long- and short-distance contributions to the gluon fusion process and thus cannot access directly the coupling between the Higgs and the top quark. We investigate the production of a boosted Higgs in association with a high-transverse momentum jet as an alternative to the t anti th channel to pin down this crucial coupling. Presented rst in the context of an effective field theory, our analysis is then applied to models of partial compositeness at the TeV scale and of natural supersymmetry.
Dattagupta, Aparajita; The ATLAS collaboration
2016-01-01
A detailed study of the techniques for identifying boosted hadronically decaying W or Z bosons is presented. The best performing algorithm for reconstructing, grooming and tagging bosonic jets as seen in studies using 8 TeV data and simulation is validated for W bosons with a wide range of transverse momenta using 13 TeV data and MC simulations. The same is studied for Z bosons in 13 TeV MC simulation. Improvement in tagger performance using detector tracking information is also studied. In addition, given that a hadronic jet has been identified as resulting from the hadronic decay of a W or Z, a technique is developed to discriminate between W and Z bosons using 8 TeV data. The alternative of using variable-R jets for capturing the hadronic decay products compared to standard techniques is also discussed.
Boosted objects: a probe of beyond the standard model physics
DEFF Research Database (Denmark)
Abdesselam, A.; Belyaev, A.; Kuutmann, E. B.
2011-01-01
We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools...
Higher-order Gaussian kernel in bootstrap boosting algorithm ...
African Journals Online (AJOL)
The bootstrap boosting algorithm is a bias reduction scheme. The adoption of higher-order Gaussian kernel in a bootstrap boosting algorithm in kernel density estimation was investigated. The algorithm used the higher-order. Gaussian kernel instead of the regular fixed kernels. A comparison of the scheme with existing ...
Boosting aquaculture production systems in Osun state: Role of ...
African Journals Online (AJOL)
This scenario leaves a high percentage of the population who depend on fish and fish products food insecure, and thus, the need to boost aquaculture production to argument the supply from the wild. The study therefore looks into the possibility of boosting the production systems through the use of micro-credit and ...
Diode-Assisted Buck-Boost Current Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Cai, Liang; Loh, P.C.
2007-01-01
This paper presents a couple of novel current source inverters (CSIs) with the enhanced current buckboost capability. With the unique diode-inductor network added between current source inverter circuitry and current boost elements, the proposed buck-boost current source inverters demonstrate...
The attentional boost effect and context memory.
Mulligan, Neil W; Smith, S Adam; Spataro, Pietro
2016-04-01
Stimuli co-occurring with targets in a detection task are better remembered than stimuli co-occurring with distractors-the attentional boost effect (ABE). The ABE is of interest because it is an exception to the usual finding that divided attention during encoding impairs memory. The effect has been demonstrated in tests of item memory but it is unclear if context memory is likewise affected. Some accounts suggest enhanced perceptual encoding or associative binding, predicting an ABE on context memory, whereas other evidence suggests a more abstract, amodal basis of the effect. In Experiment 1, context memory was assessed in terms of an intramodal perceptual detail, the font and color of the study word. Experiment 2 examined context memory cross-modally, assessing memory for the modality (visual or auditory) of the study word. Experiments 3 and 4 assessed context memory with list discrimination, in which 2 study lists are presented and participants must later remember which list (if either) a test word came from. In all experiments, item (recognition) memory was also assessed and consistently displayed a robust ABE. In contrast, the attentional-boost manipulation did not enhance context memory, whether defined in terms of visual details, study modality, or list membership. There was some evidence that the mode of responding on the detection task (motoric response as opposed to covert counting of targets) may impact context memory but there was no evidence of an effect of target detection, per se. In sum, the ABE did not occur in context memory with verbal materials. (c) 2016 APA, all rights reserved).
Glucose starvation boosts Entamoeba histolytica virulence.
Directory of Open Access Journals (Sweden)
Ayala Tovy
2011-08-01
Full Text Available The unicellular parasite, Entamoeba histolytica, is exposed to numerous adverse conditions, such as nutrient deprivation, during its life cycle stages in the human host. In the present study, we examined whether the parasite virulence could be influenced by glucose starvation (GS. The migratory behaviour of the parasite and its capability to kill mammalian cells and to lyse erythrocytes is strongly enhanced following GS. In order to gain insights into the mechanism underlying the GS boosting effects on virulence, we analyzed differences in protein expression levels in control and glucose-starved trophozoites, by quantitative proteomic analysis. We observed that upstream regulatory element 3-binding protein (URE3-BP, a transcription factor that modulates E.histolytica virulence, and the lysine-rich protein 1 (KRiP1 which is induced during liver abscess development, are upregulated by GS. We also analyzed E. histolytica membrane fractions and noticed that the Gal/GalNAc lectin light subunit LgL1 is up-regulated by GS. Surprisingly, amoebapore A (Ap-A and cysteine proteinase A5 (CP-A5, two important E. histolytica virulence factors, were strongly down-regulated by GS. While the boosting effect of GS on E. histolytica virulence was conserved in strains silenced for Ap-A and CP-A5, it was lost in LgL1 and in KRiP1 down-regulated strains. These data emphasize the unexpected role of GS in the modulation of E.histolytica virulence and the involvement of KRiP1 and Lgl1 in this phenomenon.
Boosted one dimensional fermionic superfluids on a lattice
Ray, Sayonee; Mukerjee, Subroto; Shenoy, Vijay B.
2017-09-01
We study the effect of a boost (Fermi sea displaced by a finite momentum) on one dimensional systems of lattice fermions with short-ranged interactions. In the absence of a boost such systems with attractive interactions possess algebraic superconducting order. Motivated by physics in higher dimensions, one might naively expect a boost to weaken and ultimately destroy superconductivity. However, we show that for one dimensional systems the effect of the boost can be to strengthen the algebraic superconducting order by making correlation functions fall off more slowly with distance. This phenomenon can manifest in interesting ways, for example, a boost can produce a Luther-Emery phase in a system with both charge and spin gaps by engendering the destruction of the former.
Relaxed states with plasma flow
International Nuclear Information System (INIS)
Avinash, K.; Taylor, J.B.
1991-01-01
In the theory of relaxation, a turbulent plasma reaches a state of minimum energy subject to constant magnetic helicity. In this state the plasma velocity is zero. Attempts have been made by introducing a number of different constraints, to obtain relaxed states with plasma flow. It is shown that these alternative constraints depend on two self-helicities, one for ions, and one for electrons. However, whereas there are strong arguments for the effective invariance of the original magnetic-helicity, these arguments do not apply to the self-helicities. Consequently the existence of relaxed states with flow remains in doubt. (author)
Dust in cosmic plasma environments
International Nuclear Information System (INIS)
Mendis, D.A.
1979-01-01
Cosmic dust is invariably immersed in a plasma and a radiative environment. Consequently, it is charged to some electrostatic potential which depends on the properties of the environment as well as the nature of the dust. This charging affects the physical and dynamical properties of the dust. In this paper the basic aspects of this dust-plasma interaction in several cosmic environments - including planetary magnetospheres, the heliosphere and the interstellar medium - are discussed. The physical and dynamical consequences of the interaction, as well as the pertinent observational evidence, are reviewed. Finally, the importance of the surface charge during the condensation process in plasma environments is stressed. (Auth.)
Directory of Open Access Journals (Sweden)
Alexandra J Spencer
Full Text Available The orthodox role of the invariant chain (CD74; Ii is in antigen presentation to CD4+ T cells, but enhanced CD8+ T cells responses have been reported after vaccination with vectored viral vaccines encoding a fusion of Ii to the antigen of interest. In this study we assessed whether fusion of the malarial antigen, ME-TRAP, to Ii could increase the vaccine-induced CD8+ T cell response. Following single or heterologous prime-boost vaccination of mice with a recombinant chimpanzee adenovirus vector, ChAd63, or recombinant modified vaccinia virus Ankara (MVA, higher frequencies of antigen-specific CD4+ and CD8+ T cells were observed, with the largest increases observed following a ChAd63-MVA heterologous prime-boost regimen. Studies in non-human primates confirmed the ability of Ii-fusion to augment the T cell response, where a 4-fold increase was maintained up to 11 weeks after the MVA boost. Of the numerous different approaches explored to increase vectored vaccine induced immunogenicity over the years, fusion to the invariant chain showed a consistent enhancement in CD8+ T cell responses across different animal species and may therefore find application in the development of vaccines against human malaria and other diseases where high levels of cell-mediated immunity are required.
Introducing state-trajectory control for the synchronous interleaved boost converter
DEFF Research Database (Denmark)
Peña-Alzola, Rafael; Ksiazek, Peter; Ordonez, Martin
2015-01-01
Synchronous interleaved boost converters (SIBCs) result in lower ripple currents and bidirectional power flow. The boost topology has a non-minimum phase characteristic, producing instability problems when a large bandwidth is required. Linear controllers inherently limit the boost controller...
Constructing invariant fairness measures for surfaces
DEFF Research Database (Denmark)
Gravesen, Jens; Ungstrup, Michael
2002-01-01
The paper proposes a rational method to derive fairness measures for surfaces. It works in cases where isophotes, reflection lines, planar intersection curves, or other curves are used to judge the fairness of the surface. The surface fairness measure is derived by demanding that all the given cu...... of curves. Six basic third order invariants by which the fairing measures can be expressed are defined. Furthermore, the geometry of a plane intersection curve is studied, and the variation of the total, the normal, and the geodesic curvature and the geodesic torsion is determined....
Invariant measures of mass migration processes
Czech Academy of Sciences Publication Activity Database
Fajfrová, Lucie; Gobron, T.; Saada, E.
2016-01-01
Roč. 21, č. 1 (2016), s. 1-52, č. článku 60. ISSN 1083-6489 R&D Projects: GA ČR GAP201/12/2613; GA ČR(CZ) GA16-15238S Institutional support: RVO:67985556 Keywords : interacting particle systems * product invariant measures * zero range process * target process * mass migration process * condensation Subject RIV: BA - General Mathematics Impact factor: 0.904, year: 2016 http://library.utia.cas.cz/separaty/2016/SI/fajfrova-0464455.pdf
Origin of gauge invariance in string theory
Horowitz, G. T.; Strominger, A.
1986-01-01
A first quantization of the space-time embedding Chi exp mu and the world-sheet metric rho of the open bosonic string. The world-sheet metric rho decouples from S-matrix elements in 26 dimensions. This formulation of the theory naturally includes 26-dimensional gauge transformations. The gauge invariance of S-matrix elements is a direct consequence of the decoupling of rho. Second quantization leads to a string field Phi(Chi exp mu, rho) with a gauge-covariant equation of motion.
Translational invariant shell model for Λ hypernuclei
Directory of Open Access Journals (Sweden)
Jolos R.V.
2016-01-01
Full Text Available We extend shell model for Λ hypernuclei suggested by Gal and Millener by including 2ћω excitations in the translation invariant version to estimate yields of different hyperfragments from primary p-shell hypernuclei. We are inspired by the first successful experiment done at MAMI which opens way to study baryon decay of hypernuclei. We use quantum numbers of group SU(4, [f], and SU(3, (λμ, to classify basis wave functions and calculate coefficients of fractional parentage.
The axion mass in modular invariant supergravity
International Nuclear Information System (INIS)
Butter, Daniel; Gaillard, Mary K.
2005-01-01
When supersymmetry is broken by condensates with a single condensing gauge group, there is a nonanomalous R-symmetry that prevents the universal axion from acquiring a mass. It has been argued that, in the context of supergravity, higher dimension operators will break this symmetry and may generate an axion mass too large to allow the identification of the universal axion with the QCD axion. We show that such contributions to the axion mass are highly suppressed in a class of models where the effective Lagrangian for gaugino and matter condensation respects modular invariance (T-duality)
Scale invariants from Gaussian-Hermite moments
Czech Academy of Sciences Publication Activity Database
Yang, B.; Kostková, Jitka; Flusser, Jan; Suk, Tomáš
2017-01-01
Roč. 132, č. 1 (2017), s. 77-84 ISSN 0165-1684 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : Scale invariants * Gaussian–Hermite moments * Variable modulation * Normalization * Zernike moments Subject RIV: JD - Computer Applications, Robotics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 3.110, year: 2016 http://library.utia.cas.cz/separaty/2016/ZOI/flusser-0466031.pdf
Testing Lorentz invariance in β decay
Directory of Open Access Journals (Sweden)
Sytema A.
2014-03-01
Experimentally we exploit the Gamow-Teller transition of polarized 20Na, where we can test the dependence of the β-decay rate on the spin orientation of 20Na. The polarization degree is measured using the β asymmetry, while the decay rate is measured by the γ yield. A change in the γ rate, when reversing the spin, implies Lorentz invariance violation. The decay rate should depend on sidereal time and the polarization direction relative to the rotation axis of the earth. The method of the measurement will be presented, together with the first results.
Structure of BRS-invariant local functionals
International Nuclear Information System (INIS)
Brandt, F.
1993-01-01
For a large class of gauge theories a nilpotent BRS-operator s is constructed and its cohomology in the space of local functionals of the off-shell fields is shown to be isomorphic to the cohomology of s=s+d on functions f(C,T) of tensor fields T and of variables C which are constructed of the ghosts and the connection forms. The result allows general statements about the structure of invariant classical actions and anomaly cadidates whose BRS-variation vanishes off-shell. The assumptions under which the result holds are thoroughly discussed. (orig.)
Modular invariance and covariant loop calculus
International Nuclear Information System (INIS)
Petersen, J.L.; Roland, K.O.; Sidenius, J.R.
1988-01-01
The covariant loop calculus provides an efficient technique for computing explicit expressions for the density on moduli space corresponding to arbitrary (bosonic string) loop diagrams. Since modular invariance is not manifest, however, we carry out a detailed comparison with known explicit two- and three-loop results derived using analytic geometry (one loop is known to be okay). We establish identity to 'high' order in some moduli and exactly in others. Agreement is found as a result of various nontrivial cancellations, in part related to number theory. We feel our results provide very strong support for the correctness of the covariant loop calculus approach. (orig.)
Gauge invariant actions for string models
International Nuclear Information System (INIS)
Banks, T.
1986-06-01
String models of unified interactions are elegant sets of Feynman rules for the scattering of gravitons, gauge bosons, and a host of massive excitations. The purpose of these lectures is to describe the progress towards a nonperturbative formulation of the theory. Such a formulation should make the geometrical meaning of string theory manifest and explain the many ''miracles'' exhibited by the string Feynman rules. There are some new results on gauge invariant observables, on the cosmological constant, and on the symmetries of interacting string field theory. 49 refs
Hidden Scale Invariance in Condensed Matter
DEFF Research Database (Denmark)
Dyre, J. C.
2014-01-01
. This means that the phase diagram becomes effectively one-dimensional with regard to several physical properties. Liquids and solids with isomorphs include most or all van der Waals bonded systems and metals, as well as weakly ionic or dipolar systems. On the other hand, systems with directional bonding...... (hydrogen bonds or covalent bonds) or strong Coulomb forces generally do not exhibit hidden scale invariance. The article reviews the theory behind this picture of condensed matter and the evidence for it coming from computer simulations and experiments...
Modular invariance and covariant loop calculus
International Nuclear Information System (INIS)
Petersen, J.L.; Roland, K.O.; Sidenius, J.R.
1988-01-01
The covariant loop calculus provides and efficient technique for computing explicit expressions for the density on moduli space corresponding to arbitrary (bosonic string) loop diagrams. Since modular invariance is not manifest, however, we carry out a detailed comparison with known explicit 2- and 3- loop results derived using analytic geometry (1 loop is known to be ok). We establish identity to 'high' order in some moduli and exactly in others. Agreement is found as a result of various non-trivial cancellations, in part related to number theory. We feel our results provide very strong support for the correctness of the covariant loop calculus approach. (orig.)
ResBoost: characterizing and predicting catalytic residues in enzymes
Directory of Open Access Journals (Sweden)
Freund Yoav
2009-06-01
Full Text Available Abstract Background Identifying the catalytic residues in enzymes can aid in understanding the molecular basis of an enzyme's function and has significant implications for designing new drugs, identifying genetic disorders, and engineering proteins with novel functions. Since experimentally determining catalytic sites is expensive, better computational methods for identifying catalytic residues are needed. Results We propose ResBoost, a new computational method to learn characteristics of catalytic residues. The method effectively selects and combines rules of thumb into a simple, easily interpretable logical expression that can be used for prediction. We formally define the rules of thumb that are often used to narrow the list of candidate residues, including residue evolutionary conservation, 3D clustering, solvent accessibility, and hydrophilicity. ResBoost builds on two methods from machine learning, the AdaBoost algorithm and Alternating Decision Trees, and provides precise control over the inherent trade-off between sensitivity and specificity. We evaluated ResBoost using cross-validation on a dataset of 100 enzymes from the hand-curated Catalytic Site Atlas (CSA. Conclusion ResBoost achieved 85% sensitivity for a 9.8% false positive rate and 73% sensitivity for a 5.7% false positive rate. ResBoost reduces the number of false positives by up to 56% compared to the use of evolutionary conservation scoring alone. We also illustrate the ability of ResBoost to identify recently validated catalytic residues not listed in the CSA.
Multi-Centered Invariants, Plethysm and Grassmannians
Cacciatori, Sergio L.; van Geemen, Bert
2013-01-01
Motivated by multi-centered black hole solutions of Maxwell-Einstein theories of (super)gravity in D=4 space-time dimensions, we develop some general methods, that can be used to determine all homogeneous invariant polynomials on the irreducible (SL_h(p,R) x G4)-representation (p,R), where p denotes the number of centers, and SL_h(p,R) is the "horizontal" symmetry of the system, acting upon the indices labelling the centers. The black hole electric and magnetic charges sit in the symplectic representation R of the generalized electric-magnetic (U-)duality group G4. We start with an algebraic approach based on classical invariant theory, using Schur polynomials and the Cauchy formula. Then, we perform a geometric analysis, involving Grassmannians, Pluecker coordinates, and exploiting Bott's Theorem. We focus on non-degenerate groups G4 "of type E7" relevant for (super)gravities whose (vector multiplets') scalar manifold is a symmetric space. In the triality-symmetric stu model of N=2 supergravity, we explicitl...
Duality invariant class of exact string backgrounds
Klimcík, C
1994-01-01
We consider a class of $2+D$ - dimensional string backgrounds with a target space metric having a covariantly constant null Killing vector and flat `transverse' part. The corresponding sigma models are invariant under $D$ abelian isometries and are transformed by $O(D,D)$ duality into models belonging to the same class. The leading-order solutions of the conformal invariance equations (metric, antisymmetric tensor and dilaton), as well as the action of $O(D,D)$ duality transformations on them, are exact, i.e. are not modified by $\\a'$-corrections. This makes a discussion of different space-time representations of the same string solution (related by $O(D,D|Z)$ duality subgroup) rather explicit. We show that the $O(D,D)$ duality may connect curved $2+D$-dimensional backgrounds with solutions having flat metric but, in general, non-trivial antisymmetric tensor and dilaton. We discuss several particular examples including the $2+D=4$ - dimensional background that was recently interpreted in terms of a WZW model.
Natural inflation with hidden scale invariance
Directory of Open Access Journals (Sweden)
Neil D. Barrie
2016-05-01
Full Text Available We propose a new class of natural inflation models based on a hidden scale invariance. In a very generic Wilsonian effective field theory with an arbitrary number of scalar fields, which exhibits scale invariance via the dilaton, the potential necessarily contains a flat direction in the classical limit. This flat direction is lifted by small quantum corrections and inflation is realised without need for an unnatural fine-tuning. In the conformal limit, the effective potential becomes linear in the inflaton field, yielding to specific predictions for the spectral index and the tensor-to-scalar ratio, being respectively: ns−1≈−0.025(N⋆60−1 and r≈0.0667(N⋆60−1, where N⋆≈30–65 is a number of efolds during observable inflation. This predictions are in reasonable agreement with cosmological measurements. Further improvement of the accuracy of these measurements may turn out to be critical in falsifying our scenario.
Asymptotically free theory with scale invariant thermodynamics
Ferrari, Gabriel N.; Kneur, Jean-Loïc; Pinto, Marcus Benghi; Ramos, Rudnei O.
2017-12-01
A recently developed variational resummation technique, incorporating renormalization group properties consistently, has been shown to solve the scale dependence problem that plagues the evaluation of thermodynamical quantities, e.g., within the framework of approximations such as in the hard-thermal-loop resummed perturbation theory. This method is used in the present work to evaluate thermodynamical quantities within the two-dimensional nonlinear sigma model, which, apart from providing a technically simpler testing ground, shares some common features with Yang-Mills theories, like asymptotic freedom, trace anomaly and the nonperturbative generation of a mass gap. The present application confirms that nonperturbative results can be readily generated solely by considering the lowest-order (quasiparticle) contribution to the thermodynamic effective potential, when this quantity is required to be renormalization group invariant. We also show that when the next-to-leading correction from the method is accounted for, the results indicate convergence, apart from optimally preserving, within the approximations here considered, the sought-after scale invariance.
Conformal invariance in conditioned stochastic particle systems
Schütz, Gunter M.
2017-08-01
We consider space-time correlations in generic one-dimensional stochastic interacting particle systems with short-range interactions that undergo a fluctuation with an atypically activity of particle jumps or reactions or spin flips. We briefly review the approach in the framework of the quantum Hamiltonian formalism and present examples where the dynamics during such large fluctuations is governed not by the typical stationary dynamics, but by ballistic universality classes with dynamical exponent z=1 that are described unitary conformally invariant field theories with central charge c. For reaction-diffusion and spin flip dynamics we identify critical points (a) in the Ising universality class with c=1/2 , and (b) in the universality class of the three-states Potts model with c=4/5 . For the Ising universality class we obtain a universal scaling form for the generating function of cumulants of the jump activity. For repulsive driven diffusive systems with one conservation law the regime of an atypically high current or hopping activity is generically conformally invariant with central charge c=1 .
Component-Minimized Buck-Boost Voltage Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.; Blaabjerg, Frede
2007-01-01
. In order to form a distinct neutral potential in the corresponding voltage boost circuitry for correct B4 inverter operation, necessary modifications are derived step by step. The resulted dc networks with symmetrical placement of passive components allow complete charging and equal energy distribution...... semiconductors. Besides the advantage of reduced active components, buck-boost B4 inverters use a little more passive components when compared with buck-boost B6 inverters, which would allow a selectable tradeoff in practice. Moreover, analysis for discontinuous conduction mode of inductor current reveals...
On logarithmic extensions of local scale-invariance
Energy Technology Data Exchange (ETDEWEB)
Henkel, Malte, E-mail: malte.henkel@ijl.nancy-universite.fr [Groupe de Physique Statistique, Département de Physique de la Matière et des Matériaux, Institut Jean Lamour (CNRS UMR 7198), Université de Lorraine Nancy, B.P. 70239, F-54506 Vandoeuvre lès Nancy Cedex (France)
2013-04-11
Ageing phenomena far from equilibrium naturally present dynamical scaling and in many situations this may be generalised to local scale-invariance. Generically, the absence of time-translation-invariance implies that each scaling operator is characterised by two independent scaling dimensions. Building on analogies with logarithmic conformal invariance and logarithmic Schrödinger-invariance, this work proposes a logarithmic extension of local scale-invariance, without time-translation-invariance. Carrying this out requires in general to replace both scaling dimensions of each scaling operator by Jordan cells. Co-variant two-point functions are derived for the most simple case of a two-dimensional logarithmic extension. Their form is compared to simulational data for autoresponse functions in several universality classes of non-equilibrium ageing phenomena.
Conformal invariance in the long-range Ising model
Directory of Open Access Journals (Sweden)
Miguel F. Paulos
2016-01-01
Full Text Available We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.
SMART STRATEGY TO BOOST STUDENTS’ READING COMPREHENSION
Directory of Open Access Journals (Sweden)
Muhammad Lukman Syafi’i
2015-05-01
Full Text Available Reading as one of language skills plays significant roles in the teaching English as a foreign language. Since the teacher still uses the conventional way to teach reading, students‘ ability in reading comprehension seems still unsatisfactory yet. So, teacher should explore and develop new strategies. One of strategies in reading comprehension that can trigger our students to attain that purpose is SMART (Self Monitoring Approach for Reading and Thinking strategy. This study is developing SMART strategy to boost the reading comprehension achievement of the ninth grade students. The research applies a collaborative classroom action research design in which the researcher and the collaborative teacher work together in preparing a suitable procedure of SMART strategy, designing the lesson plan, determining the criteria of success, implementing the action, observing, and doing reflection. The finding indicated that SMART strategy was successful to enhance students‘ motivation to be actively involved in the instructional process. The improvement on the students‘ participation was 75% in Cycle 1 and 87% in Cycle 2.
Designing boosting ensemble of relational fuzzy systems.
Scherer, Rafał
2010-10-01
A method frequently used in classification systems for improving classification accuracy is to combine outputs of several classifiers. Among various types of classifiers, fuzzy ones are tempting because of using intelligible fuzzy if-then rules. In the paper we build an AdaBoost ensemble of relational neuro-fuzzy classifiers. Relational fuzzy systems bond input and output fuzzy linguistic values by a binary relation; thus, fuzzy rules have additional, comparing to traditional fuzzy systems, weights - elements of a fuzzy relation matrix. Thanks to this the system is better adjustable to data during learning. In the paper an ensemble of relational fuzzy systems is proposed. The problem is that such an ensemble contains separate rule bases which cannot be directly merged. As systems are separate, we cannot treat fuzzy rules coming from different systems as rules from the same (single) system. In the paper, the problem is addressed by a novel design of fuzzy systems constituting the ensemble, resulting in normalization of individual rule bases during learning. The method described in the paper is tested on several known benchmarks and compared with other machine learning solutions from the literature.
Subcellular localization prediction through boosting association rules.
Yoon, Yongwook; Lee, Gary Geunbae
2012-01-01
Computational methods for predicting protein subcellular localization have used various types of features, including N-terminal sorting signals, amino acid compositions, and text annotations from protein databases. Our approach does not use biological knowledge such as the sorting signals or homologues, but use just protein sequence information. The method divides a protein sequence into short $k$-mer sequence fragments which can be mapped to word features in document classification. A large number of class association rules are mined from the protein sequence examples that range from the N-terminus to the C-terminus. Then, a boosting algorithm is applied to those rules to build up a final classifier. Experimental results using benchmark datasets show our method is excellent in terms of both the classification performance and the test coverage. The result also implies that the $k$-mer sequence features which determine subcellular locations do not necessarily exist in specific positions of a protein sequence. Online prediction service implementing our method is available at http://isoft.postech.ac.kr/research/BCAR/subcell.
RAMOBoost: Ranked Minority Oversampling in Boosting.
Chen, Sheng; He, Haibo; Garcia, Edwardo A
2010-10-01
In recent years, learning from imbalanced data has attracted growing attention from both academia and industry due to the explosive growth of applications that use and produce imbalanced data. However, because of the complex characteristics of imbalanced data, many real-world solutions struggle to provide robust efficiency in learning-based applications. In an effort to address this problem, this paper presents Ranked Minority Oversampling in Boosting (RAMOBoost), which is a RAMO technique based on the idea of adaptive synthetic data generation in an ensemble learning system. Briefly, RAMOBoost adaptively ranks minority class instances at each learning iteration according to a sampling probability distribution that is based on the underlying data distribution, and can adaptively shift the decision boundary toward difficult-to-learn minority and majority class instances by using a hypothesis assessment procedure. Simulation analysis on 19 real-world datasets assessed over various metrics-including overall accuracy, precision, recall, F-measure, G-mean, and receiver operation characteristic analysis-is used to illustrate the effectiveness of this method.
Distinctiveness and the Attentional Boost Effect.
Smith, S Adam; Mulligan, Neil W
2018-02-01
The typical pattern of results in divided attention experiments is that subjects in a full attention (FA) condition perform markedly better on tests of memory than subjects in a divided attention (DA) condition which forces subjects to split their attention between studying to-be-remembered stimuli and completing some peripheral task. Nevertheless, recent research has revealed an exception wherein stimuli presented concurrently with targets in a detection task are better remembered than stimuli which co-occur with distractors. Research on this phenomenon-the Attentional Boost Effect (ABE)-has demonstrated that the ABE is reduced or eliminated for words made distinct by their word frequency or orthographic properties-forms of secondary distinctiveness. However, it is unclear how primary distinctiveness effects may interact with the ABE. The current study observed how perceptual and semantic manipulations of primary distinctiveness via the isolation paradigm interact with the ABE, and revealed these interactions to be fundamentally different than those of secondary distinctiveness. Specifically, whereas the effects of secondary distinctiveness in earlier studies were found to be redundant with the ABE, the current study demonstrated that items characterized by primary distinctiveness enhanced memory performance independently of the ABE. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Corinne Pralavorio
2015-01-01
The first HIE-ISOLDE cryomodule was commissioned at the end of October. The radioactive ion beams can now be accelerated to 4.3 MeV per nucleon. The ISOLDE beamline that supplies the Miniball array. The first HIE-ISOLDE cryomodule can be seen in the background, in its light-grey cryostat. ISOLDE is getting an energy boost. The first cryomodule of the new superconducting linear accelerator HIE-ISOLDE (High Intensity and Energy ISOLDE), located downstream of the REX-ISOLDE accelerator, increases the energy of the radioactive ion beams from 3 to 4.3 MeV per nucleon. It supplies the Miniball array, where an experiment using radioactive zinc ions (see box) began at the end of October. This is the first stage in the commissioning of HIE-ISOLDE. The facility will ultimately be equipped with four cryomodules that will accelerate the beams to 10 MeV per nucleon. Each cryomodule has five accelerating cavities and a solenoid, which focuses the beam. All of these components are superconducting. This first ...
Skein Invariants of Links and Their State Sum Models
Directory of Open Access Journals (Sweden)
Louis H. Kauffman
2017-10-01
Full Text Available We present the new skein invariants of classical links, H [ H ] , K [ K ] and D [ D ] , based on the invariants of links, H, K and D, denoting the regular isotopy version of the Homflypt polynomial, the Kauffman polynomial and the Dubrovnik polynomial. The invariants are obtained by abstracting the skein relation of the corresponding invariant and making a new skein algorithm comprising two computational levels: first producing unlinked knotted components, then evaluating the resulting knots. The invariants in this paper, were revealed through the skein theoretic definition of the invariants Θ d related to the Yokonuma–Hecke algebras and their 3-variable generalization Θ , which generalizes the Homflypt polynomial. H [ H ] is the regular isotopy counterpart of Θ . The invariants K [ K ] and D [ D ] are new generalizations of the Kauffman and the Dubrovnik polynomials. We sketch skein theoretic proofs of the well-definedness and topological properties of these invariants. The invariants of this paper are reformulated into summations of the generating invariants (H, K, D on sublinks of the given link L, obtained by partitioning L into collections of sublinks. The first such reformulation was achieved by W.B.R. Lickorish for the invariant Θ and we generalize it to the Kauffman and Dubrovnik polynomial cases. State sum models are formulated for all the invariants. These state summation models are based on our skein template algorithm which formalizes the skein theoretic process as an analogue of a statistical mechanics partition function. Relationships with statistical mechanics models are articulated. Finally, we discuss physical situations where a multi-leveled course of action is taken naturally.
Differential invariants for higher-rank tensors. A progress report
International Nuclear Information System (INIS)
Tapial, V.
2004-07-01
We outline the construction of differential invariants for higher-rank tensors. In section 2 we outline the general method for the construction of differential invariants. A first result is that the simplest tensor differential invariant contains derivatives of the same order as the rank of the tensor. In section 3 we review the construction for the first-rank tensors (vectors) and second-rank tensors (metrics). In section 4 we outline the same construction for higher-rank tensors. (author)
Dimuon Level-1 invariant mass in 2017 data
CMS Collaboration
2018-01-01
This document shows the Level-1 (L1) dimuon invariant mass with and without L1 muon track extrapolation to the collision vertex and how it compares with the offline reconstructed dimuon invariant mass. The plots are made with the data sample collected in 2017. The event selection, the matching algorithm and the results of the L1 dimuon invariant mass are described in the next pages.
Geometric Invariant Measuring the Deviation from Kerr Data
Bäckdahl, Thomas; Kroon, Juan A. Valiente
2010-01-01
A geometrical invariant for regular asymptotically Euclidean data for the vacuum Einstein field equations is constructed. This invariant vanishes if and only if the data correspond to a slice of the Kerr black hole spacetime --thus, it provides a measure of the non-Kerr-like behavior of generic data. In order to proceed with the construction of the geometric invariant, we introduce the notion of approximate Killing spinors.
Geometric Invariant Measuring the Deviation from Kerr Data
Bäckdahl, Thomas; Valiente Kroon, Juan A.
2010-06-01
A geometrical invariant for regular asymptotically Euclidean data for the vacuum Einstein field equations is constructed. This invariant vanishes if and only if the data correspond to a slice of the Kerr black hole spacetime—thus, it provides a measure of the non-Kerr-like behavior of generic data. In order to proceed with the construction of the geometric invariant, we introduce the notion of approximate Killing spinors.
Cotton-Type and Joint Invariants for Linear Elliptic Systems
Directory of Open Access Journals (Sweden)
A. Aslam
2013-01-01
that Cotton-type invariants derived from these two approaches are identical. Furthermore, Cotton-type and joint invariants for a general system of two linear elliptic equations are also obtained from the Laplace-type and joint invariants for a system of two linear hyperbolic equations equivalent to the system of linear elliptic equations by complex changes of the independent variables. Examples are presented to illustrate the results.
Binary optical filters for scale invariant pattern recognition
Reid, Max B.; Downie, John D.; Hine, Butler P.
1992-01-01
Binary synthetic discriminant function (BSDF) optical filters which are invariant to scale changes in the target object of more than 50 percent are demonstrated in simulation and experiment. Efficient databases of scale invariant BSDF filters can be designed which discriminate between two very similar objects at any view scaled over a factor of 2 or more. The BSDF technique has considerable advantages over other methods for achieving scale invariant object recognition, as it also allows determination of the object's scale. In addition to scale, the technique can be used to design recognition systems invariant to other geometric distortions.
Experimental Design for Testing Local Lorentz Invariance Violations in Gravity
Directory of Open Access Journals (Sweden)
Ya-Fen Chen
2017-10-01
Full Text Available Local Lorentz invariance is an important component of General Relativity. Testing for Local Lorentz invariance can not only probe the foundation stone of General Relativity but also help to explore the unified theory for General Relativity and quantum mechanics. In this paper, we search the Local Lorentz invariance violation associated with operators of mass dimension d = 6 in the pure-gravity sector with short-range gravitational experiments. To enlarge the Local Lorentz invariance violation signal effectively, we design a new experiment in which the constraints of all fourteen violation coefficients may be improved by about one order of magnitude.
On the invariance of residues of Feynman graphs
International Nuclear Information System (INIS)
Bierenbaum, Isabella; Kreckel, Richard; Kreimer, Dirk
2002-01-01
We use simple iterated one-loop graphs in massless Yukawa theory and QED to pose the following question: what are the symmetries of the residues of a graph under a permutation of places to insert subdivergences. The investigation confirms partial invariance of the residue under such permutations: the highest weight transcendental is invariant under such a permutation. For QED this result is gauge invariant, i.e., the permutation invariance holds for any gauge. Computations are done making use of the Hopf algebra structure of graphs and employing GiNaC to automate the calculations
Experimental Design for Testing Local Lorentz Invariance Violations in Gravity
Chen, Ya-Fen; Tan, Yu-Jie; Shao, Cheng-Gang
2017-09-01
Local Lorentz invariance is an important component of General Relativity. Testing for Local Lorentz invariance can not only probe the foundation stone of General Relativity but also help to explore the unified theory for General Relativity and quantum mechanics. In this paper, we search the Local Lorentz invariance violation associated with operators of mass dimension d=6 in the pure-gravity sector with short-range gravitational experiments. To enlarge the Local Lorentz invariance violation signal effectively, we design a new experiment in which the constraints of all fourteen violation coefficients may be improved by about one order of magnitude
Note on Weyl versus conformal invariance in field theory
Energy Technology Data Exchange (ETDEWEB)
Wu, Feng [Nanchang University, Department of Physics, Nanchang (China)
2017-12-15
It was argued recently that conformal invariance in flat spacetime implies Weyl invariance in a general curved background for unitary theories and possible anomalies in the Weyl variation of scalar operators are identified. We argue that generically unitarity alone is not sufficient for a conformal field theory to be Weyl invariant. Furthermore, we show explicitly that when a unitary conformal field theory couples to gravity in a Weyl-invariant way, each primary scalar operator that is either relevant or marginal in the unitary conformal field theory corresponds to a Weyl-covariant operator in the curved background. (orig.)
Metric Ranking of Invariant Networks with Belief Propagation
Energy Technology Data Exchange (ETDEWEB)
Tao, Changxia [Xi' an Jiaotong University, China; Ge, Yong [University of North Carolina, Charlotte; Song, Qinbao [Xi' an Jiaotong University, China; Ge, Yuan [Anhui Polytechnic University, China; Omitaomu, Olufemi A [ORNL
2014-01-01
The management of large-scale distributed information systems relies on the effective use and modeling of monitoring data collected at various points in the distributed information systems. A promising approach is to discover invariant relationships among the monitoring data and generate invariant networks, where a node is a monitoring data source (metric) and a link indicates an invariant relationship between two monitoring data. Such an invariant network representation can help system experts to localize and diagnose the system faults by examining those broken invariant relationships and their related metrics, because system faults usually propagate among the monitoring data and eventually lead to some broken invariant relationships. However, at one time, there are usually a lot of broken links (invariant relationships) within an invariant network. Without proper guidance, it is difficult for system experts to manually inspect this large number of broken links. Thus, a critical challenge is how to effectively and efficiently rank metrics (nodes) of invariant networks according to the anomaly levels of metrics. The ranked list of metrics will provide system experts with useful guidance for them to localize and diagnose the system faults. To this end, we propose to model the nodes and the broken links as a Markov Random Field (MRF), and develop an iteration algorithm to infer the anomaly of each node based on belief propagation (BP). Finally, we validate the proposed algorithm on both realworld and synthetic data sets to illustrate its effectiveness.
Boosting the Kerr geometry in an arbitrary direction
Balasin, Herbert; Nachbagauer, Herbert
1996-04-01
We construct ultrarelativistic Kerr geometries from their distributional energy - momentum tensors. The latter are obtained by boosting Kerr's distributional energy - momentum tensor in arbitrary directions, thereby generalizing previous work by the authors.
Superconducting Electric Boost Pump for Nuclear Thermal Propulsion, Phase II
National Aeronautics and Space Administration — Design, fabrication, assembly and test of the Florida Turbine Technologies, Inc. (FTT) concept for a submersible, superconducting electric boost pump during Phase II...
TOPOLOGICAL REVIEW AND ANALYSIS OF DC-DC BOOST CONVERTERS
Directory of Open Access Journals (Sweden)
V. INDRA GANDHI
2017-06-01
Full Text Available DC voltage boost up is essential in numerous applications; especially considering Photovoltaic (PV based renewable power generation system. The conventional DC-DC boost converter is the most admired configuration for this scheme, even if the converter efficiency is restricted at duty cycle near to maximum value. In order to find solution to the problem and improve its conversion capability, many converter configurations have been implemented so far. With this circumstance, this research work proposes to give overview of a few most imperative research works related to DC-DC boost converters. Some configurations are covered and classified basically based on the application. The major benefits and disadvantages related to the available techniques are also briefly conveyed. At last, a proper evaluation is recognized among the important types of DC-DC boost converters in terms of efficiency, number of components, and stability.
Superconducting Electric Boost Pump for Nuclear Thermal Propulsion, Phase I
National Aeronautics and Space Administration — A submersible, superconducting electric boost pump sized to meet the needs of future Nuclear Thermal Propulsion systems in the 25,000 lbf thrust range is proposed....
The Synergy Between PAV and AdaBoost.
Wilbur, W John; Yeganova, Lana; Kim, Won
2005-11-01
Schapire and Singer's improved version of AdaBoost for handling weak hypotheses with confidence rated predictions represents an important advance in the theory and practice of boosting. Its success results from a more efficient use of information in weak hypotheses during updating. Instead of simple binary voting a weak hypothesis is allowed to vote for or against a classification with a variable strength or confidence. The Pool Adjacent Violators (PAV) algorithm is a method for converting a score into a probability. We show how PAV may be applied to a weak hypothesis to yield a new weak hypothesis which is in a sense an ideal confidence rated prediction and that this leads to an optimal updating for AdaBoost. The result is a new algorithm which we term PAV-AdaBoost. We give several examples illustrating problems for which this new algorithm provides advantages in performance.
Invariant relationships deriving from classical scaling transformations
International Nuclear Information System (INIS)
Bludman, Sidney; Kennedy, Dallas C.
2011-01-01
Because scaling symmetries of the Euler-Lagrange equations are generally not variational symmetries of the action, they do not lead to conservation laws. Instead, an extension of Noether's theorem reduces the equations of motion to evolutionary laws that prove useful, even if the transformations are not symmetries of the equations of motion. In the case of scaling, symmetry leads to a scaling evolutionary law, a first-order equation in terms of scale invariants, linearly relating kinematic and dynamic degrees of freedom. This scaling evolutionary law appears in dynamical and in static systems. Applied to dynamical central-force systems, the scaling evolutionary equation leads to generalized virial laws, which linearly connect the kinetic and potential energies. Applied to barotropic hydrostatic spheres, the scaling evolutionary equation linearly connects the gravitational and internal energy densities. This implies well-known properties of polytropes, describing degenerate stars and chemically homogeneous nondegenerate stellar cores.
Kahler stabilized, modular invariant heterotic string models
Energy Technology Data Exchange (ETDEWEB)
Gaillard, Mary K.; Gaillard, Mary K.; Nelson, Brent D.
2007-03-19
We review the theory and phenomenology of effective supergravity theories based on orbifold compactifications of the weakly-coupled heterotic string. In particular, we consider theories in which the four-dimensional theory displays target space modular invariance and where the dilatonic mode undergoes Kahler stabilization. A self-contained exposition of effective Lagrangian approaches to gaugino condensation and heterotic string theory is presented, leading to the development of the models of Binétruy, Gaillard and Wu. Various aspects of the phenomenology of this class of models are considered. These include issues of supersymmetry breaking and superpartner spectra, the role of anomalous U(1) factors, issues of flavor and R-parity conservation, collider signatures, axion physics, and early universe cosmology. For the vast majority of phenomenological considerations the theories reviewed here compare quite favorably to other string-derived models in the literature. Theoretical objections to the framework and directions for further research are identified and discussed.
Blocks of finite groups and their invariants
Sambale, Benjamin
2014-01-01
Providing a nearly complete selection of up-to-date methods and results on block invariants with respect to their defect groups, this book covers the classical theory pioneered by Brauer, the modern theory of fusion systems introduced by Puig, the geometry of numbers developed by Minkowski, the classification of finite simple groups, and various computer assisted methods. In a powerful combination, these tools are applied to solve many special cases of famous open conjectures in the representation theory of finite groups. Most of the material is drawn from peer-reviewed journal articles, but there are also new previously unpublished results. In order to make the text self-contained, detailed proofs are given whenever possible. Several tables add to the text's usefulness as a reference. The book is aimed at experts in group theory or representation theory who may wish to make use of the presented ideas in their research.
Gauge invariance and Weyl-polymer quantization
Strocchi, Franco
2016-01-01
The book gives an introduction to Weyl non-regular quantization suitable for the description of physically interesting quantum systems, where the traditional Dirac-Heisenberg quantization is not applicable. The latter implicitly assumes that the canonical variables describe observables, entailing necessarily the regularity of their exponentials (Weyl operators). However, in physically interesting cases -- typically in the presence of a gauge symmetry -- non-observable canonical variables are introduced for the description of the states, namely of the relevant representations of the observable algebra. In general, a gauge invariant ground state defines a non-regular representation of the gauge dependent Weyl operators, providing a mathematically consistent treatment of familiar quantum systems -- such as the electron in a periodic potential (Bloch electron), the Quantum Hall electron, or the quantum particle on a circle -- where the gauge transformations are, respectively, the lattice translations, the magne...
Joint survival probability via truncated invariant copula
International Nuclear Information System (INIS)
Kim, Jeong-Hoon; Ma, Yong-Ki; Park, Chan Yeol
2016-01-01
Highlights: • We have studied an issue of dependence structure between default intensities. • We use a multivariate shot noise intensity process, where jumps occur simultaneously and their sizes are correlated. • We obtain the joint survival probability of the integrated intensities by using a copula. • We apply our theoretical result to pricing basket default swap spread. - Abstract: Given an intensity-based credit risk model, this paper studies dependence structure between default intensities. To model this structure, we use a multivariate shot noise intensity process, where jumps occur simultaneously and their sizes are correlated. Through very lengthy algebra, we obtain explicitly the joint survival probability of the integrated intensities by using the truncated invariant Farlie–Gumbel–Morgenstern copula with exponential marginal distributions. We also apply our theoretical result to pricing basket default swap spreads. This result can provide a useful guide for credit risk management.
Scale-invariance in soft gamma repeaters
Chang, Zhe; Lin, Hai-Nan; Sang, Yu; Wang, Ping
2017-06-01
The statistical properties of the soft gamma repeater SGR J1550-5418 are investigated carefully. We find that the cumulative distributions of fluence, peak flux and duration can be well fitted by a bent power law, while the cumulative distribution of waiting time follows a simple power law. In particular, the probability density functions of fluctuations of fluence, peak flux, and duration have a sharp peak and fat tails, which can be well fitted by a q-Gaussian function. The q values keep approximately steady for different scale intervals, indicating a scale-invariant structure of soft gamma repeaters. Those results support that the origin of soft gamma repeaters is crustquakes of neutron stars with extremely strong magnetic fields. Supported by National Natural Science Foundation of China (11375203, 11675182, 11690022, 11603005), and Fundamental Research Funds for Central Universities (106112016CDJCR301206)
Quantum critical phenomena and conformal invariance
International Nuclear Information System (INIS)
Zhe Chang.
1995-05-01
We show that the Abelian bosonization of continuum limit of the 1D Hubbard model corresponds to the 2D explicitly conformal invariant Gaussian model at weak coupling limit. A universality argument is used to extend the equivalence to an entire segment of the critical line of the strongly correlated electron system. An integral equation satisfied by the mapping function between critical lines of the 1D Hubbard model and 2D Gaussian model is obtained and then solved in some limiting cases. By making use of the fact that the free Hubbard system reduces to four fermions and each of them is related to a c = 1/2 conformal field theory, we present exactly the partition function of the Hubbard model on a finite 1D lattice. (author). 16 refs
Null tests of time-reversal invariance
International Nuclear Information System (INIS)
Conzett, H.E.
1993-01-01
Because null tests of parity conservation exist in nuclear and particle reactions, it has been possible to measure very precisely the (weak-interaction) parity nonconserving contribution to the process. There is, however, a proof of the nonexistence of a comparable null test of time-reversal invariance. As a result, reaction tests of T symmetry have, at best, achieved precisions several orders of magnitude below that of the tests of P symmetry. Since transmission experiments are not included in the nonexistence proof, the existing formalism used to describe spin observables in neutron transmission experiments has been expanded to include explicitly the target spin. Through this formalism, the time-reversal-violating (and parity nonconserving) forward scattering amplitudes are identified, along with the corresponding spin observables. It is noted that new and more precise tests of T symmetry are provided in transmission experiments, and that such investigations are applicable more generally in nuclear and particle physics
Conformally invariant braneworld and the cosmological constant
International Nuclear Information System (INIS)
Guendelman, E.I.
2004-01-01
A six-dimensional braneworld scenario based on a model describing the interaction of gravity, gauge fields and 3+1 branes in a conformally invariant way is described. The action of the model is defined using a measure of integration built of degrees of freedom independent of the metric. There is no need to fine tune any bulk cosmological constant or the tension of the two (in the scenario described here) parallel branes to obtain zero cosmological constant, the only solutions are those with zero 4D cosmological constant. The two extra dimensions are compactified in a 'football' fashion and the branes lie on the two opposite poles of the compact 'football-shaped' sphere
2001 BUDGET: Research Gets Hefty Boost in 2001 Defense Budget.
Malakoff, D
2000-09-08
Next year's $289 billion defense budget, which President Bill Clinton signed last month, includes big boosts for a host of science programs, from endangered species research to developing laser weapons. And with the two major presidential candidates pledging further boosts, the Pentagon's portfolio is attracting increasing attention from the life sciences community as well. But some analysts worry that Congress and the Pentagon may be shortchanging long-term, high-risk research in favor of projects with a more certain payoff.
Searches with Boosted Objects at ATLAS and CMS
Behr, K; The ATLAS collaboration
2014-01-01
This talk presents an overview of searches for new physics in boosted final states conducted by the ATLAS and CMS experiments during Run-I of the LHC. An emphasis is put on techniques for the reconstruction and identification of both hadronic and leptonic decays of objects with large transverse momenta: Various substructure and grooming techniques as well as modified lepton isolation criteria are reviewed and their use in the most common algorithms for boosted top and boson tagging is discussed.
Time reversal invariance in polarized neutron decay
Energy Technology Data Exchange (ETDEWEB)
Wasserman, Eric G. [Harvard Univ., Cambridge, MA (United States)
1994-03-01
An experiment to measure the time reversal invariance violating (T-violating) triple correlation (D) in the decay of free polarized neutrons has been developed. The detector design incorporates a detector geometry that provides a significant improvement in the sensitivity over that used in the most sensitive of previous experiments. A prototype detector was tested in measurements with a cold neutron beam. Data resulting from the tests are presented. A detailed calculation of systematic effects has been performed and new diagnostic techniques that allow these effects to be measured have been developed. As the result of this work, a new experiment is under way that will improve the sensitivity to D to 3 x 10^{-4} or better. With higher neutron flux a statistical sensitivity of the order 3 x 10^{-5} is ultimately expected. The decay of free polarized neutrons (n → p + e + $\\bar{v}$_{e}) is used to search for T-violation by measuring the triple correlation of the neutron spin polarization, and the electron and proton momenta (σ_{n} • p_{p} x p_{e}). This correlation changes sign under reversal of the motion. Since final state effects in neutron decay are small, a nonzero coefficient, D, of this correlation indicates the violation of time reversal invariance. D is measured by comparing the numbers of coincidences in electron and proton detectors arranged symmetrically about a longitudinally polarized neutron beam. Particular care must be taken to eliminate residual asymmetries in the detectors or beam as these can lead to significant false effects. The Standard Model predicts negligible T-violating effects in neutron decay. Extensions to the Standard Model include new interactions some of which include CP-violating components. Some of these make first order contributions to D.
Conformally invariant processes in the plane
International Nuclear Information System (INIS)
Lawler, G.F.
2004-01-01
These lectures will focus on recent rigorous work on continuum limits of planar lattice models from statistical physics at criticality. For an introduction, I would like to discuss the general problem of critical exponents and scaling limits for lattice models in equilibrium statistical mechanics. There are a number of models, [e.g., self-avoiding walk (polymers), percolation, loop-erased random walk (uniform spanning trees, domino tilings), Ising model, Potts model, nonintersecting simple random walks] that fall under this general framework. These lectures will consider the case d = 2. Mathematicians are now starting to understand rigorously the scaling limit of two-dimensional systems. For most of these models, the general strategy can be described as: Construct possible continuum limits for these models. Show that there are only a limited number of such limits that are conformally invariant. Prove that the lattice model approaches the continuum limit. We should think of the first step as being similar for all of these models. We will spend the next couple of lectures discussing the continuum limits. One example you should already know - the scaling limit of simple random walk is Brownian motion (which in two dimensions is conformally invariant). The important new ideas are restriction measures and stochastic Loewner evolution (SLE). The later lectures will discuss rigorous results about lattice models approaching the continuum limit - we will discuss nonintersecting random walks (which can be shown to be equivalent to problems about exceptional sets of Brownian paths), percolation on the triangular lattice, and the loop-erased random walk. As a rule, the methods used for the second step are particular to each model
Time reversal invariance in polarized neutron decay
International Nuclear Information System (INIS)
Wasserman, E.G.
1994-03-01
An experiment to measure the time reversal invariance violating (T-violating) triple correlation (D) in the decay of free polarized neutrons has been developed. The detector design incorporates a detector geometry that provides a significant improvement in the sensitivity over that used in the most sensitive of previous experiments. A prototype detector was tested in measurements with a cold neutron beam. Data resulting from the tests are presented. A detailed calculation of systematic effects has been performed and new diagnostic techniques that allow these effects to be measured have been developed. As the result of this work, a new experiment is under way that will improve the sensitivity to D to 3 x 10 -4 or better. With higher neutron flux a statistical sensitivity of the order 3 x 10 -5 is ultimately expected. The decay of free polarized neutrons (n → p + e + bar v e ) is used to search for T-violation by measuring the triple correlation of the neutron spin polarization, and the electron and proton momenta (σ n · p p x p e ). This correlation changes sign under reversal of the motion. Since final state effects in neutron decay are small, a nonzero coefficient, D, of this correlation indicates the violation of time reversal invariance. D is measured by comparing the numbers of coincidences in electron and proton detectors arranged symmetrically about a longitudinally polarized neutron beam. Particular care must be taken to eliminate residual asymmetries in the detectors or beam as these can lead to significant false effects. The Standard Model predicts negligible T-violating effects in neutron decay. Extensions to the Standard Model include new interactions some of which include CP-violating components. Some of these make first order contributions to D
Rigid invariance as derived from BRS invariance. The abelian Higgs model
International Nuclear Information System (INIS)
Kraus, E.
1995-02-01
Consequences of a symmetry, e.g. relations amongst Green functions, are renormalization scheme independently expressed in terms of a rigid Ward identity. The corresponding local version yields information on the respective current. In the case of spontaneous breakdown one has to define the theory via the BRS invariance and thus to construct rigid and current Ward identity non-trivially in accordance with it. We performed this construction to all orders of perturbation theory in the abelian Higgs model as a prelude to the standard model. A technical tool of interest in itself is the use of a doublet of external scalar ''background'' fields. The Callan-Symanzik equation has an interesting form and follows easily once the rigid invariance is established. (orig.)
Buck-Boost Current-Source Inverters With Diode-Inductor Network
DEFF Research Database (Denmark)
Gao, Feng; Liang, Chao; Loh, Poh Chiang
2009-01-01
This paper presents a number of novel currentsource inverters (CSIs) with enhanced current buck-boost capability. By adding a unique diode-inductor network between the inverter circuitry and current-boost elements, the proposed buck-boost CSIs demonstrate a doubling of current-boost capability...
The parametrization invariant and gauge invariant effective actions in quantum field theory
International Nuclear Information System (INIS)
Odintsov, S.D.
1990-01-01
The review of formulation and methods of calculation of the parametrization and gauge invariant effective actions in quantum field theory is given. As an example the Vilkovisky-De Witt Effective action (EA) is studied (this EA is a natural representative of gauge and parametrization invariant EA's). The examples where the use of the standard EA leads to the ambiguity are demonstrated. This happens as the result of dependence of the standard EA upon the choice of gauge condition. These examples are as follows: Coleman-Weinberg potential in the finite theories and symmetry breaking, EA in quantum gravity with matter and d=5 gauged supergravity, the possibility of spontaneous supersymmetry breaking in N=1 supergravity and the spontaneous compactification in the multidimensional R 2 -gravity. In all these cases the one-loop Vilkovisky-De Witt EA is found and therefore the problem of gauge dependence of EA is solved. The dependence of standard EA of composite fields upon the gauge is studied for the general gauge theories. The class of gauge and parametrization invariant EA's of the composite fields is offered. (author)
Projective invariants in a conformal finsler space - I
International Nuclear Information System (INIS)
Mishra, C.K.; Singh, M.P.
1989-12-01
The projective invariants in a conformal Finsler space have been studied in regard to certain tensor and scalar which are invariant under projective transformation in a Finsler space. They have been the subject of further investigation by the present authors. (author). 8 refs
N=2 supergravity in superspace: the invariant action
International Nuclear Information System (INIS)
Gal'perin, A.S.; Sokachev, E.
1987-01-01
This paper continues the formulation of harmonic superspace supergravity. We write down the invariant action for the first off-shell version of the theory. The proof of the invariance relies on the existence of a new 'hybrid' basis in harmonic superspace in which semi-chirality combined with analyticity are manifest
Measurement Invariance of the Pay Satisfaction Questionnaire across Three Countries
Lievens, Filip; Anseel, Frederik; Harris, Michael M.; Eisenberg, Jacob
2007-01-01
In recent years, pay satisfaction has been increasingly studied in an international context, prompting the importance of examining whether the Pay Satisfaction Questionnaire (PSQ) is invariant across countries other than the United States. This study investigated the measurement invariance across three countries, namely, the United States (N =…
Rotation-invariant fingerprint matching using radon and DCT
Indian Academy of Sciences (India)
Sangita Bharkad
2017-11-20
Nov 20, 2017 ... invariant features using radon transform and translation invariance is achieved using DCT. ... et al [11] introduced a convolutional neural-network-based approach for automatic extraction of minutiae points ...... recognition, machine intelligence and biometrics (PRMI),. Chapter 17, Springer, pp. 417–455.
Measurement Invariance: A Foundational Principle for Quantitative Theory Building
Nimon, Kim; Reio, Thomas G., Jr.
2011-01-01
This article describes why measurement invariance is a critical issue to quantitative theory building within the field of human resource development. Readers will learn what measurement invariance is and how to test for its presence using techniques that are accessible to applied researchers. Using data from a LibQUAL+[TM] study of user…
On Action Invariance under Linear Spinor-Vector Supersymmetry
Directory of Open Access Journals (Sweden)
Kazunari Shima
2006-01-01
Full Text Available We show explicitly that a free Lagrangian expressed in terms of scalar, spinor, vector and Rarita-Schwinger (RS fields is invariant under linear supersymmetry transformations generated by a global spinor-vector parameter. A (generalized gauge invariance of the Lagrangian for the RS field is also discussed.
Polynomial invariants to quantify Four-body Correlations
Sharma, Santosh Shelly; Sharma, Naresh Kumar
2013-03-01
Local unitary invariance and notion of negativity fonts are used as the principle tools to construct four qubit polynomial invariants of degree 8, 12, and 24. Determinants of negativity fonts are linked to matrices obtained from state operator through selective partial transposition. Our general aim is to construct the polynomial invariants that quantify entanglement due to K - body correlations in an N-qubit (N ? K) pure state. This is done by constructing N-qubit invariants from multivariate forms with (K - 1)-qubit invariants as coefficients. In particular, the invariant that quantifies entanglement due to N-body correlations is obtained from a biform having as coefficients the N - 1 qubit invariants. A polynomial invariant that is non-zero on four qubit pure states with four-body correlations and zero on all other states, is identified. Classification of four qubit states into seven major classes, using criterion based on the nature of correlations, is discussed. We gratefully acknowledge financial support from CNPq Brazil and Faep, UEL, Brazil.
The Scale Invariant Synchrotron Jet of Flat Spectrum Radio Quasars
Indian Academy of Sciences (India)
2016-01-27
Jan 27, 2016 ... In this paper, the scale invariance of the synchrotron jet of Flat Spectrum Radio Quasars has been studied using a sample of combined sources from FKM04 and from SDSS DR3 catalogue. Since the research of scale invariance has been focused on sub-Eddington cases that can be fitted onto the ...
Conformal invariance in the long-range Ising model
Paulos, M.F.; Rychkov, S.; van Rees, B.C.; Zan, B.
We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to
The undergeneration of permutation invariance as a criterion for logicality
Dutilh Novaes, Catarina
2014-01-01
Permutation invariance is often presented as the correct criterion for logicality. The basic idea is that one can demarcate the realm of logic by isolating speciﬁc entities—logical notions or constants—and that permutation invariance would provide a philosophically motivated and technically
Integrable lattice models, graphs and modular invariant conformal field theories
International Nuclear Information System (INIS)
Francesco, P.
1992-01-01
This paper reviews the construction of integrable height models attached to graphs in connection with compact Lie groups. The continuum limit of these models yields conformally invariant field theories. A direct relation between graphs and (Kac-Moody or coset) modular invariants is proposed
Construction of exact complex dynamical invariant of a two ...
Indian Academy of Sciences (India)
physics pp. 999–1009. Construction of exact complex dynamical invariant of a two-dimensional classical system. FAKIR CHAND and S C MISHRA. Department ... namical invariants for both time-dependent and time-independent classical systems. [1–3]. .... where [·, ·] is the Poisson bracket, which in view of the definition eq.
Existence of a last invariant of conservative motion
International Nuclear Information System (INIS)
Hall, L.S.
1982-01-01
A general theory of integrable systems in two dimensions is formulated and applied. (The theory also has applications to more dimensions). The constraints are found which admit to general integrability of the orbits for magnetic forces as well as for forces derivable from a potential. When a system admits a given invariant, the invariant is found. A number of examples including known and apparently previously unknown invariants are given. The theory of exact integrals of the motion also can be extended to the derivation of approximate invariants. The general theory admits a variational principle, among other approximation techniques, for the computation of a best approximate invariant. The problem of the general cubic potential with one symmetric coordinate, V = 1/2 Ax 2 + 1/2 By 2 + Cx 2 y + 1/3 Dy 3 (of which the well-studied Henon-Heiles potential is the special case for A = B and C = -D), is examined in detail
Boosted Fast Flux Loop Final Report
Energy Technology Data Exchange (ETDEWEB)
Boosted Fast Flux Loop Project Staff
2009-09-01
The Boosted Fast Flux Loop (BFFL) project was initiated to determine basic feasibility of designing, constructing, and installing in a host irradiation facility, an experimental vehicle that can replicate with reasonable fidelity the fast-flux test environment needed for fuels and materials irradiation testing for advanced reactor concepts. Originally called the Gas Test Loop (GTL) project, the activity included (1) determination of requirements that must be met for the GTL to be responsive to potential users, (2) a survey of nuclear facilities that may successfully host the GTL, (3) conceptualizing designs for hardware that can support the needed environments for neutron flux intensity and energy spectrum, atmosphere, flow, etc. needed by the experimenters, and (4) examining other aspects of such a system, such as waste generation and disposal, environmental concerns, needs for additional infrastructure, and requirements for interfacing with the host facility. A revised project plan included requesting an interim decision, termed CD-1A, that had objectives of' establishing the site for the project at the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL), deferring the CD 1 application, and authorizing a research program that would resolve the most pressing technical questions regarding GTL feasibility, including issues relating to the use of booster fuel in the ATR. Major research tasks were (1) hydraulic testing to establish flow conditions through the booster fuel, (2) mini-plate irradiation tests and post-irradiation examination to alleviate concerns over corrosion at the high heat fluxes planned, (3) development and demonstration of booster fuel fabrication techniques, and (4) a review of the impact of the GTL on the ATR safety basis. A revised cooling concept for the apparatus was conceptualized, which resulted in renaming the project to the BFFL. Before the subsequent CD-1 approval request could be made, a decision was made in April
Lorentz boosted frame simulation technique in Particle-in-cell methods
Yu, Peicheng
In this dissertation, we systematically explore the use of a simulation method for modeling laser wakefield acceleration (LWFA) using the particle-in-cell (PIC) method, called the Lorentz boosted frame technique. In the lab frame the plasma length is typically four orders of magnitude larger than the laser pulse length. Using this technique, simulations are performed in a Lorentz boosted frame in which the plasma length, which is Lorentz contracted, and the laser length, which is Lorentz expanded, are now comparable. This technique has the potential to reduce the computational needs of a LWFA simulation by more than four orders of magnitude, and is useful if there is no or negligible reflection of the laser in the lab frame. To realize the potential of Lorentz boosted frame simulations for LWFA, the first obstacle to overcome is a robust and violent numerical instability, called the Numerical Cerenkov Instability (NCI), that leads to unphysical energy exchange between relativistically drifting particles and their radiation. This leads to unphysical noise that dwarfs the real physical processes. In this dissertation, we first present a theoretical analysis of this instability, and show that the NCI comes from the unphysical coupling of the electromagnetic (EM) modes and Langmuir modes (both main and aliasing) of the relativistically drifting plasma. We then discuss the methods to eliminate them. However, the use of FFTs can lead to parallel scalability issues when there are many more cells along the drifting direction than in the transverse direction(s). We then describe an algorithm that has the potential to address this issue by using a higher order finite difference operator for the derivative in the plasma drifting direction, while using the standard second order operators in the transverse direction(s). The NCI for this algorithm is analyzed, and it is shown that the NCI can be eliminated using the same strategies that were used for the hybrid FFT
International Nuclear Information System (INIS)
Dawson, J.M.
1988-01-01
The Superconducting Supercollider (SSC) will require an 87-kilometer accelerator ring to boost particles to 40 TeV. The SSC's size is due in part to the fact that its operating principle is the same one that has dominated accelerator design for 50 years: it guides particles by means of magnetic fields and propels them by strong electric fields. If one were to build an equally powerful but smaller accelerator, one would need to increase the strength of the guiding and propelling fields. Actually, however, conventional technology may not be able to provide significant increases in field strength. There are two reasons. First, the forces from magnetic fields are becoming greater than the structural forces that hold a magnetic material together; the magnets that produce these fields would themselves be torn apart. Second, the energy from electric fields is reaching the energies that bind electrons to atoms; it would tear electrons from nuclei in the accelerator's support structures. It is the electric field problem that plasma accelerators can overcome. Plasma particle accelerators are based on the principle that particles can be accelerated by the electric fields generated within a plasma. Because the plasma has already been ionized, plasma particle accelerators are not susceptible to electron dissociation. They can in theory sustain accelerating fields thousands of times stronger that conventional technologies. So far two methods for creating plasma waves for accelerators have been proposed and tested: the wakefield and the beat wave. Although promising electric fields have been produced, more research is necessary to determine whether plasma particle accelerators can compete with the existing accelerators. 7 figs
AN ILLUMINATION INVARIANT TEXTURE BASED FACE RECOGNITION
Directory of Open Access Journals (Sweden)
K. Meena
2013-11-01
Full Text Available Automatic face recognition remains an interesting but challenging computer vision open problem. Poor illumination is considered as one of the major issue, since illumination changes cause large variation in the facial features. To resolve this, illumination normalization preprocessing techniques are employed in this paper to enhance the face recognition rate. The methods such as Histogram Equalization (HE, Gamma Intensity Correction (GIC, Normalization chain and Modified Homomorphic Filtering (MHF are used for preprocessing. Owing to great success, the texture features are commonly used for face recognition. But these features are severely affected by lighting changes. Hence texture based models Local Binary Pattern (LBP, Local Derivative Pattern (LDP, Local Texture Pattern (LTP and Local Tetra Patterns (LTrPs are experimented under different lighting conditions. In this paper, illumination invariant face recognition technique is developed based on the fusion of illumination preprocessing with local texture descriptors. The performance has been evaluated using YALE B and CMU-PIE databases containing more than 1500 images. The results demonstrate that MHF based normalization gives significant improvement in recognition rate for the face images with large illumination conditions.
Achieving Translationally Invariant Trapped Ion Rings
Urban, Erik; Li, Hao-Kun; Noel, Crystal; Hemmerling, Boerge; Zhang, Xiang; Haeffner, Hartmut
2017-04-01
We present the design and implementation of a novel surface ion trap design in a ring configuration. By eliminating the need for wire bonds through the use of electrical vias and using a rotationally invariant electrode configuration, we have realized a trap that is able to trap up to 20 ions in a ring geometry 45um in diameter, 400um above the trap surface. This large trapping height to ring diameter ratio allows for global addressing of the ring with both lasers and electric fields in the chamber, thereby increasing our ability to control the ring as a whole. Applying compensating electric fields, we measure very low tangential trap frequencies (less than 20kHz) corresponding to rotational barriers down to 4mK. This measurement is currently limited by the temperature of the ions but extrapolation indicates the barrier can be reduced much further with more advanced cooling techniques. Finally, we show that we are able to reduce this energy barrier sufficiently such that the ions are able to overcome it either through thermal motion or rotational motion and delocalize over the full extent of the ring. This work was funded by the Keck Foundation and the NSF.
Computing with scale-invariant neural representations
Howard, Marc; Shankar, Karthik
The Weber-Fechner law is perhaps the oldest quantitative relationship in psychology. Consider the problem of the brain representing a function f (x) . Different neurons have receptive fields that support different parts of the range, such that the ith neuron has a receptive field at xi. Weber-Fechner scaling refers to the finding that the width of the receptive field scales with xi as does the difference between the centers of adjacent receptive fields. Weber-Fechner scaling is exponentially resource-conserving. Neurophysiological evidence suggests that neural representations obey Weber-Fechner scaling in the visual system and perhaps other systems as well. We describe an optimality constraint that is solved by Weber-Fechner scaling, providing an information-theoretic rationale for this principle of neural coding. Weber-Fechner scaling can be generated within a mathematical framework using the Laplace transform. Within this framework, simple computations such as translation, correlation and cross-correlation can be accomplished. This framework can in principle be extended to provide a general computational language for brain-inspired cognitive computation on scale-invariant representations. Supported by NSF PHY 1444389 and the BU Initiative for the Physics and Mathematics of Neural Systems,.
Numerical continuation of normally hyperbolic invariant manifolds
Broer, H. W.; Hagen, A.; Vegter, G.
2007-06-01
This paper deals with the numerical continuation of invariant manifolds regardless of the restricted dynamics. Common examples of such manifolds include limit sets, codimension 1 manifolds separating basins of attraction (separatrices), stable/unstable/centre manifolds, nested hierarchies of attracting manifolds in dissipative systems and manifolds appearing in bifurcations. The approach is based on the general principle of normal hyperbolicity, where the graph transform leads to the numerical algorithms. This gives a highly multiple purpose method. The graph transform and linear graph transform compute the perturbed manifold with its hyperbolic splitting. To globally discretize manifolds, a discrete tubular neighbourhood is used, induced by a transverse bundle composed of discrete stable and unstable bundles. This approach allows the development of the discrete graph transform/linear graph transform analogous to the usual smooth case. Convergence results are given. The discrete vector bundle construction and associated local k-plane interpolation may be of independent interest. A practical numerical implementation for solving the global equations underlying the graph transform is proposed. Relevant numerical techniques are discussed and computational tests included. An additional application is the computation of the 'slow-transient' surface of an enzyme reaction.
Scale-invariant gravity: spacetime recovered
International Nuclear Information System (INIS)
Kelleher, Bryan
2004-01-01
The configuration space of general relativity is superspace-the space of all Riemannian 3-metrics modulo diffeomorphisms. However, it has been argued that the configuration space for gravity should be conformal superspace-the space of all Riemannian 3-metrics modulo diffeomorphisms and conformal transformations. Recently a manifestly three-dimensional theory was constructed with conformal superspace as the configuration space. Here a fully four-dimensional action is constructed so as to be invariant under conformal transformations of the 4-metric using general relativity as a guide. This action is then decomposed to a (3 + 1)-dimensional form and from this to its Jacobi form. The surprising thing is that the new theory turns out to be precisely the original three-dimensional theory. The physical data are identified and used to find the physical representation of the theory. In this representation the theory is extremely similar to general relativity. The clarity of the four-dimensional picture should prove very useful for comparing the theory with those aspects of general relativity which are usually treated in the four-dimensional framework
ICECUBE NEUTRINOS AND LORENTZ INVARIANCE VIOLATION
Energy Technology Data Exchange (ETDEWEB)
Amelino-Camelia, Giovanni [Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sez. Roma1, P.le A. Moro 2, I-00185 Roma (Italy); Guetta, D. [Osservatorio astronomico di Roma, v. Frascati 33, I-00040 Monte Porzio Catone (Italy); Piran, Tsvi [The Racah Institute for Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)
2015-06-20
The IceCube neutrino telescope has found so far no evidence of gamma-ray burst (GRB) neutrinos. We here notice that these results assume the same travel times from source to telescope for neutrinos and photons, an assumption that is challenged by some much-studied pictures of spacetime quantization. We briefly review previous results suggesting that limits on quantum-spacetime effects obtained for photons might not be applicable to neutrinos, and we then observe that the outcome of GRB-neutrino searches could depend strongly on whether one allows for neutrinos to be affected by the minute effects of Lorentz invariance violation (LIV) predicted by some relevant quantum-spacetime models. We discuss some relevant issues using as an illustrative example three neutrinos that were detected by IceCube in good spatial coincidence with GRBs, but hours before the corresponding gamma rays. In general, this could happen if the earlier arrival reflects quantum-spacetime-induced LIV, but, as we stress, some consistency criteria must be enforced in order to properly test such a hypothesis. Our analysis sets the stage for future GRB-neutrino searches that could systematically test the possibility of quantum-spacetime-induced LIV.
Implications of conformal invariance in momentum space
Bzowski, Adam; McFadden, Paul; Skenderis, Kostas
2014-03-01
We present a comprehensive analysis of the implications of conformal invariance for 3-point functions of the stress-energy tensor, conserved currents and scalar operators in general dimension and in momentum space. Our starting point is a novel and very effective decomposition of tensor correlators which reduces their computation to that of a number of scalar form factors. For example, the most general 3-point function of a conserved and traceless stress-energy tensor is determined by only five form factors. Dilatations and special conformal Ward identities then impose additional conditions on these form factors. The special conformal Ward identities become a set of first and second order differential equations, whose general solution is given in terms of integrals involving a product of three Bessel functions (`triple- K integrals'). All in all, the correlators are completely determined up to a number of constants, in agreement with well-known position space results. In odd dimensions 3-point functions are finite without renormalisation while in even dimensions non-trivial renormalisation in required. In this paper we restrict ourselves to odd dimensions. A comprehensive analysis of renormalisation will be discussed elsewhere. This paper contains two parts that can be read independently of each other. In the first part, we explain the method that leads to the solution for the correlators in terms of triple- K integrals while the second part contains a self-contained presentation of all results. Readers interested only in results may directly consult the second part of the paper.
Lifshitz invariants from ab initio lattice dynamics
Schiaffino, Andrea; Stengel, Massimiliano
The interaction between different order parameters is vital to explain the emergence of new functionalities (hybrid improper ferroelectricity, magnetoelectricity) in multiferroic systems. While considerable theoretical efforts have been directed in the past at studying couplings (e.g. trilinear or biquadratic) that occur in a homogeneous sample, recent research has revealed an increasing number of cases where the interesting physics emerges from inhomogeneities in some order parameter (e.g. flexoelectricity, domain walls), rather than the uniform bulk phase itself. These are usually described in phenomenological theories via symmetry-allowed gradient-mediated terms, the so-called Lifshitz invariants. Here I will present a general method to calculate such couplings ab initio, within the framework of density-functional perturbation theory. I will start with a brief overview on the most challenging aspects of these calculations, i.e. how to deal with the breakdown of the translational symmetry, and with the unusual electrostatic effects that occur in such a regime. Next, I will demonstrate this strategy in practice by presenting calculations of the most relevant gradient coefficients involving strain, octahedral tilts and polarization in ferroelastic SrTiO3. MINECO-Spain through Grants No. FIS2013-48668-C2-2-P and No. SEV-2015-0496, and by Generalitat de Catalunya (Grant No. 2014SRG301).
Parity and time invariance violation in mercury
International Nuclear Information System (INIS)
Ginges, J.S.M.; Dzuba, V.A.; Flambaum, V.V.; Kozlov, M.G.
2002-01-01
Full text: In a recent experiment, a stringent upper limit was placed on the atomic electric dipole moment (EDM) of 199 Hg corresponding to the best limit on an atomic EDM to date. This limit can be interpreted in terms of a limit on a parity-and time-invariance violating (P,T-odd) nuclear electric moment, the Schiff moment. This moment can arise in the nucleus due to an intrinsic EDM of an unpaired nucleon or a P,T-odd interaction between nucleons. In previous calculations the electrostatic potential of the Schiff moment was expressed in a singular form which must be treated carefully to avoid divergences in the electronic matrix elements. We have shown that the electric field distribution inside the nucleus arising from the Schiff moment is constant and directed along the nuclear spin. This allows us to express the Schiff moment in a form more convenient for numerical relativistic atomic calculations. We have calculated the atomic EDM induced in Hg due to the Schiff moment (for which no direct calculation has previously been performed) and have placed new limits on the fundamental P,T-odd parameters. These limits strongly constrain competing theories of CP-violation
Spatially invariant computations in stereoscopic vision.
Vidal-Naquet, Michel; Gepshtein, Sergei
2012-01-01
PERCEPTION OF STEREOSCOPIC DEPTH REQUIRES THAT VISUAL SYSTEMS SOLVE A CORRESPONDENCE PROBLEM: find parts of the left-eye view of the visual scene that correspond to parts of the right-eye view. The standard model of binocular matching implies that similarity of left and right images is computed by inter-ocular correlation. But the left and right images of the same object are normally distorted relative to one another by the binocular projection, in particular when slanted surfaces are viewed from close distance. Correlation often fails to detect correct correspondences between such image parts. We investigate a measure of inter-ocular similarity that takes advantage of spatially invariant computations similar to the computations performed by complex cells in biological visual systems. This measure tolerates distortions of corresponding image parts and yields excellent performance over a much larger range of surface slants than the standard model. The results suggest that, rather than serving as disparity detectors, multiple binocular complex cells take part in the computation of inter-ocular similarity, and that visual systems are likely to postpone commitment to particular binocular disparities until later stages in the visual process.
Search for New Light Higgs Bosons in Boosted Tau Final States with the CMS Experiment
AUTHOR|(CDS)2081769
In this dissertation, I present a search for non-standard decays of a Standard Model-likeHiggs boson to pairs of light bosons, as predicted in models with extended Higgs sectors.In two Higgs doublet models, including the next-to-minimal supersymmetric standardmodel, the Higgs boson can decay into a pair of light pseudoscalars a.In this search, the gluon fusion, W and Z associated Higgs, and vector boson fusionproduction channels for the Higgs are all considered, and the decay H →aa with a → τ τis reconstructed from the tau decay products. The ﬁnal state is characterized by oneisolated high pT muon plus at least one highly boosted pair of taus, of which one of thetaus is required to decay to a muon.Using 19.7 fb−1 of 8 TeV center of mass pp collision data recorded by the CompactMuon Solenoid experiment at the Large Hadron Collider, a counting experiment is performed in a region of high di-tau invariant mass. We have found no excess of events abovethe Standard Model backgrounds, and the observed data ...
First search for boosted Higgs boson production using the H->bb decay with CMS
CERN. Geneva
2017-01-01
An inclusive search for the standard model Higgs boson produced with high transverse momentum decaying to a bottom-antibottom quark pair has been performed using a data set of pp collisions at √s = 13 TeV collected with the CMS experiment at LHC. The data sample corresponds to an integrated luminosity of 35.9 fb−1. High-transverse-momentum Higgs bosons are reconstructed in a single jet with radius R = 0.8. Jet substructure and dedicated b-tagging techniques are used to identify boosted H → bb. The resulting experimental signature is a peak over a falling background in the distribution of the invariant mass of the jet. The Z process validates the analysis strategy and is observed with a local significance of 5.1 standard deviations for the first time in the single jet topology. An excess of events is observed above the expected background with a local significance of 1.3 standard deviations for a Higgs boson mass of 125 GeV. The signal strength corresponding to this excess, relative to that of the standa...
Substructure boosts to dark matter annihilation from Sommerfeld enhancement
International Nuclear Information System (INIS)
Bovy, Jo
2009-01-01
The recently introduced Sommerfeld enhancement of the dark matter annihilation cross section has important implications for the detection of dark matter annihilation in subhalos in the Galactic halo. In addition to the boost to the dark matter annihilation cross section from the high densities of these subhalos with respect to the main halo, an additional boost caused by the Sommerfeld enhancement results from the fact that they are kinematically colder than the Galactic halo. If we further believe the generic prediction of the cold dark matter paradigm that in each subhalo there is an abundance of substructure which is approximately self-similar to that of the Galactic halo, then I show that additional boosts coming from the density enhancements of these small substructures and their small velocity dispersions enhance the dark matter annihilation cross section even further. I find that very large boost factors (10 5 to 10 9 ) are obtained in a large class of models. The implications of these boost factors for the detection of dark matter annihilation from dwarf spheroidal galaxies in the Galactic halo are such that, generically, they outshine the background gamma-ray flux and are detectable by the Fermi Gamma-ray Space Telescope.
Invariant measures of the 2D Euler and Vlasov equations
International Nuclear Information System (INIS)
Bouchet, Freddy; Corvellec, Marianne
2010-01-01
We discuss invariant measures of partial differential equations such as the 2D Euler or Vlasov equations. For the 2D Euler equations, starting from the Liouville theorem, valid for N-dimensional approximations of the dynamics, we define the microcanonical measure as a limit measure where N goes to infinity. When only the energy and enstrophy invariants are taken into account, we give an explicit computation to prove the following result: the microcanonical measure is actually a Young measure corresponding to the maximization of a mean-field entropy. We explain why this result remains true for more general microcanonical measures, when all the dynamical invariants are taken into account. We give an explicit proof that these microcanonical measures are invariant measures for the dynamics of the 2D Euler equations. We describe a more general set of invariant measures and discuss briefly their stability and their consequence for the ergodicity of the 2D Euler equations. The extension of these results to the Vlasov equations is also discussed, together with a proof of the uniqueness of statistical equilibria, for Vlasov equations with repulsive convex potentials. Even if we consider, in this paper, invariant measures only for Hamiltonian equations, with no fluxes of conserved quantities, we think this work is an important step towards the description of non-equilibrium invariant measures with fluxes
Boosted Fast Flux Loop Alternative Cooling Assessment
Energy Technology Data Exchange (ETDEWEB)
Glen R. Longhurst; Donna Post Guillen; James R. Parry; Douglas L. Porter; Bruce W. Wallace
2007-08-01
The Gas Test Loop (GTL) Project was instituted to develop the means for conducting fast neutron irradiation tests in a domestic radiation facility. It made use of booster fuel to achieve the high neutron flux, a hafnium thermal neutron absorber to attain the high fast-to-thermal flux ratio, a mixed gas temperature control system for maintaining experiment temperatures, and a compressed gas cooling system to remove heat from the experiment capsules and the hafnium thermal neutron absorber. This GTL system was determined to provide a fast (E > 0.1 MeV) flux greater than 1.0E+15 n/cm2-s with a fast-to-thermal flux ratio in the vicinity of 40. However, the estimated system acquisition cost from earlier studies was deemed to be high. That cost was strongly influenced by the compressed gas cooling system for experiment heat removal. Designers were challenged to find a less expensive way to achieve the required cooling. This report documents the results of the investigation leading to an alternatively cooled configuration, referred to now as the Boosted Fast Flux Loop (BFFL). This configuration relies on a composite material comprised of hafnium aluminide (Al3Hf) in an aluminum matrix to transfer heat from the experiment to pressurized water cooling channels while at the same time providing absorption of thermal neutrons. Investigations into the performance this configuration might achieve showed that it should perform at least as well as its gas-cooled predecessor. Physics calculations indicated that the fast neutron flux averaged over the central 40 cm (16 inches) relative to ATR core mid-plane in irradiation spaces would be about 1.04E+15 n/cm2-s. The fast-to-thermal flux ratio would be in excess of 40. Further, the particular configuration of cooling channels was relatively unimportant compared with the total amount of water in the apparatus in determining performance. Thermal analyses conducted on a candidate configuration showed the design of the water coolant and
Static analysis of class invariants in Java programs
Bonilla-Quintero, Lidia Dionisia
2011-12-01
This paper presents a technique for the automatic inference of class invariants from Java bytecode. Class invariants are very important for both compiler optimization and as an aid to programmers in their efforts to reduce the number of software defects. We present the original DC-invariant analysis from Adam Webber, talk about its shortcomings and suggest several different ways to improve it. To apply the DC-invariant analysis to identify DC-invariant assertions, all that one needs is a monotonic method analysis function and a suitable assertion domain. The DC-invariant algorithm is very general; however, the method analysis can be highly tuned to the problem in hand. For example, one could choose shape analysis as the method analysis function and use the DC-invariant analysis to simply extend it to an analysis that would yield class-wide invariants describing the shapes of linked data structures. We have a prototype implementation: a system we refer to as "the analyzer" that infers DC-invariant unary and binary relations and provides them to the user in a human readable format. The analyzer uses those relations to identify unnecessary array bounds checks in Java programs and perform null-reference analysis. It uses Adam Webber's relational constraint technique for the class-invariant binary relations. Early results with the analyzer were very imprecise in the presence of "dirty-called" methods. A dirty-called method is one that is called, either directly or transitively, from any constructor of the class, or from any method of the class at a point at which a disciplined field has been altered. This result was unexpected and forced an extensive search for improved techniques. An important contribution of this paper is the suggestion of several ways to improve the results by changing the way dirty-called methods are handled. The new techniques expand the set of class invariants that can be inferred over Webber's original results. The technique that produces better
Invariants for minimal conformal supergravity in six dimensions
Energy Technology Data Exchange (ETDEWEB)
Butter, Daniel [Nikhef Theory Group,Science Park 105, 1098 XG Amsterdam (Netherlands); Kuzenko, Sergei M. [School of Physics M013, The University of Western Australia,35 Stirling Highway, Crawley W.A. 6009 (Australia); Novak, Joseph; Theisen, Stefan [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,Am Mühlenberg 1, D-14476 Golm (Germany)
2016-12-15
We develop a new off-shell formulation for six-dimensional conformal supergravity obtained by gauging the 6D N=(1,0) superconformal algebra in superspace. This formulation is employed to construct two invariants for 6D N=(1,0) conformal supergravity, which contain C{sup 3} and C◻C terms at the component level. Using a conformal supercurrent analysis, we prove that these exhaust all such invariants in minimal conformal supergravity. Finally, we show how to construct the supersymmetric F◻F invariant in curved superspace.
Hermite-symmetry and super-gauge-invariance
Energy Technology Data Exchange (ETDEWEB)
Treder, H.J. (Akademie der Wissenschaften der DDR, Potsdam-Babelsberg. Einstein-Laboratorium fuer Theoretische Physik)
1985-03-01
Within a unitary general relativistic field theory the metric fundamental tensor and the affinities are to be considered as independent field variables under the condition that besides the coordinate covariance the invariance for 'transformations preserving parallelism' (Einstein's A-gauge-invariance) exists. For a (non-degenerate) hermitian fundamental tensor the demand for super-gauge-invariance leads to the hermitian symmetry of both the affinities and the Ricci tensor. The hermitian continuation of general relativity into the complex domain leads therefore to the Einstein-Schroedinger field equations.
Verification of Java Programs using Symbolic Execution and Invariant Generation
Pasareanu, Corina; Visser, Willem
2004-01-01
Software verification is recognized as an important and difficult problem. We present a norel framework, based on symbolic execution, for the automated verification of software. The framework uses annotations in the form of method specifications an3 loop invariants. We present a novel iterative technique that uses invariant strengthening and approximation for discovering these loop invariants automatically. The technique handles different types of data (e.g. boolean and numeric constraints, dynamically allocated structures and arrays) and it allows for checking universally quantified formulas. Our framework is built on top of the Java PathFinder model checking toolset and it was used for the verification of several non-trivial Java programs.
Gauge invariance properties and singularity cancellations in a modified PQCD
Cabo-Montes de Oca, Alejandro; Cabo, Alejandro; Rigol, Marcos
2006-01-01
The gauge-invariance properties and singularity elimination of the modified perturbation theory for QCD introduced in previous works, are investigated. The construction of the modified free propagators is generalized to include the dependence on the gauge parameter $\\alpha $. Further, a functional proof of the independence of the theory under the changes of the quantum and classical gauges is given. The singularities appearing in the perturbative expansion are eliminated by properly combining dimensional regularization with the Nakanishi infrared regularization for the invariant functions in the operator quantization of the $\\alpha$-dependent gauge theory. First-order evaluations of various quantities are presented, illustrating the gauge invariance-properties.
Assessing the Gender Invariance of the Modern Homonegativity Scale.
Romero, Daniel H; Morera, Osvaldo F; Wiebe, John S
2015-01-01
The measurement invariance of the Modern Homonegativity Scale (MHS) was examined among heterosexual female (n = 449) and male (n = 329) university students who were predominantly Mexican American. The MHS demonstrated full invariance of factor loadings and partial invariance of latent intercepts. At the latent mean level, heterosexual men compared to heterosexual women held more negative attitudes toward both gay men and lesbian women. There were no latent mean differences in attitudes toward gay men and lesbian women when rated by either heterosexual men or heterosexual women. The MHS can be used by heterosexual men and heterosexual women to assess their homonegativity.
Evolution of Brain Tumor and Stability of Geometric Invariants
Directory of Open Access Journals (Sweden)
K. Tawbe
2008-01-01
Full Text Available This paper presents a method to reconstruct and to calculate geometric invariants on brain tumors. The geometric invariants considered in the paper are the volume, the area, the discrete Gauss curvature, and the discrete mean curvature. The volume of a tumor is an important aspect that helps doctors to make a medical diagnosis. And as doctors seek a stable calculation, we propose to prove the stability of some invariants. Finally, we study the evolution of brain tumor as a function of time in two or three years depending on patients with MR images every three or six months.
Invariant renormalization method for nonlinear realizations of dynamical symmetries
International Nuclear Information System (INIS)
Kazakov, D.I.; Pervushin, V.N.; Pushkin, S.V.
1977-01-01
The structure of ultraviolet divergences is investigated for the field theoretical models with nonlinear realization of the arbitrary semisimple Lie group, with spontaneously broken symmetry of vacuum. An invariant formulation of the background field method of renormalization is proposed which gives the manifest invariant counterterms off mass shell. A simple algorithm for construction of counterterms is developed. It is based on invariants of the group of dynamical symmetry in terms of the Cartan forms. The results of one-loop and two-loop calculations are reported
Estimation of reliability of a interleaving PFC boost converter
Directory of Open Access Journals (Sweden)
Gulam Amer Sandepudi
2010-01-01
Full Text Available Reliability plays an important role in power supplies. For other electronic equipment, a certain failure mode, at least for a part of the total system, can often be employed without serious (critical effects. However, for power supply no such condition can be accepted, since very high demands on its reliability must be achieved. At higher power levels, the continuous conduction mode (CCM boost converter is preferred topology for implementation a front end with PFC. As a result, significant efforts have been made to improve the performance of high boost converter. This paper is one of the efforts for improving the performance of the converter from the reliability point of view. In this paper, interleaving boost power factor correction converter is simulated with single switch in continuous conduction mode (CCM, discontinuous conduction mode (DCM and critical conduction mode (CRM under different output power ratings. Results of the converter are explored from reliability point of view.
Radiotherapy Boost Following Conservative Surgery for Locally Advanced Breast Cancer
International Nuclear Information System (INIS)
Cendales, Ricardo; Ospino, Rosalba; Torres, Felipe; Cotes, Martha
2009-01-01
Nearly half of breast cancer patients in developing countries present with a locally advanced cancer. Treatment is centered on a multimodal approach based on chemotherapy, surgery and radiotherapy. The growing use of neoadjuvant chemotherapy has led to a more conservative surgical approach; nonetheless, it is not yet considered as a standard. There are no clear recommendations on the use of a radiotherapy boost in such situation. A Medline search was developed. Most articles are retrospective series. Survival free of locoregional relapse in patients treated with neoadjuvant chemotherapy, breast conserving surgery and radiotherapy is good. All articles described a boost administered to nearly all patients without regard to their prognostic factors, given that a locally advanced tumor is already considered as a poor prognostic factor. Even tough the poor level of evidence, a recommendation can be made: radiotherapy boost should be administered to all patients with locally advanced breast cancer treated with neoadjuvant chemotherapy and breast conserving surgery.
Boosted black holes on Kaluza-Klein bubbles
International Nuclear Information System (INIS)
Iguchi, Hideo; Mishima, Takashi; Tomizawa, Shinya
2007-01-01
We construct an exact stationary solution of black-hole-bubble sequence in the five-dimensional Kaluza-Klein theory by using solitonic solution-generating techniques. The solution describes two stationary black holes with topology S 3 on a Kaluza-Klein bubble and has a linear momentum component in the compactified direction. We call the solution boosted black holes on Kaluza-Klein bubble because it has the linear momentum. The Arnowitt-Deser-Misner mass and the linear momentum depend on the two boosted velocity parameters of black holes. In the effective four-dimensional theory, the solution has an electric charge which is proportional to the linear momentum. The solution includes the static solution found by Elvang and Horowitz. The small and the big black holes limits are investigated. The relation between the solution and the single boosted black string are considered
Active pre-filters for dc/dc Boost regulators
Directory of Open Access Journals (Sweden)
Carlos Andrés Ramos-Paja
2014-05-01
Full Text Available This paper proposes an active pre-filter to mitigate the current harmonics generated by classical dc/dc Boost regulators, which generate current ripples proportional to the duty cycle. Therefore, high output voltage conditions, i.e., high voltage conversion ratios, produce high current harmonics that must be filtered to avoid damage or source losses. Traditionally, these current components are filtered using electrolytic capacitors, which introduce reliability problems because of their high failure rate. The solution introduced in this paper instead uses a dc/dc converter based on the parallel connection of the Boost canonical cells to filter the current ripples generated by the Boost regulator, improving the system reliability. This solution provides the additional benefits of improving the overall efficiency and the voltage conversion ratio. Finally, the solution is validated with simulations and experimental results.
Performance of Boosted W Boson Identification with the ATLAS Detector
The ATLAS collaboration
2014-01-01
This note presents the performance of a variety of techniques used to identify highly- boosted hadronically-decaying $W$ bosons. The studies presented here are divided into two parts: the first is based on Monte Carlo simulation, and the second compares the simulations to 20.3$\\pm$0.6 fb$^{-1}$ of proton-–proton collisions data collected by the ATLAS detector in 2012 at $\\sqrt{s} = 8$ TeV. Various tagging approaches and different grooming algorithms are compared in simulation, using a signal of large-$R$ jets containing a highly boosted $W$ boson and a background of large-$R$ jets originating from high-momentum light quarks or gluons. These techniques could also be utilised to identify hadronic decays of boosted $Z$ and Higgs bosons. A sample enriched in $t\\bar{t}\\to (W^+b)(W^-\\bar{b}) \\to (q\\bar{q}b)(\\mu \\bar{\
Self-boosting vaccines and their implications for herd immunity.
Arinaminpathy, Nimalan; Lavine, Jennie S; Grenfell, Bryan T
2012-12-04
Advances in vaccine technology over the past two centuries have facilitated far-reaching impact in the control of many infections, and today's emerging vaccines could likewise open new opportunities in the control of several diseases. Here we consider the potential, population-level effects of a particular class of emerging vaccines that use specific viral vectors to establish long-term, intermittent antigen presentation within a vaccinated host: in essence, "self-boosting" vaccines. In particular, we use mathematical models to explore the potential role of such vaccines in situations where current immunization raises only relatively short-lived protection. Vaccination programs in such cases are generally limited in their ability to raise lasting herd immunity. Moreover, in certain cases mass vaccination can have the counterproductive effect of allowing an increase in severe disease, through reducing opportunities for immunity to be boosted through natural exposure to infection. Such dynamics have been proposed, for example, in relation to pertussis and varicella-zoster virus. In this context we show how self-boosting vaccines could open qualitatively new opportunities, for example by broadening the effective duration of herd immunity that can be achieved with currently used immunogens. At intermediate rates of self-boosting, these vaccines also alleviate the potential counterproductive effects of mass vaccination, through compensating for losses in natural boosting. Importantly, however, we also show how sufficiently high boosting rates may introduce a new regime of unintended consequences, wherein the unvaccinated bear an increased disease burden. Finally, we discuss important caveats and data needs arising from this work.
The Lateral Decubitus Breast Boost: Description, Rationale, and Efficacy
International Nuclear Information System (INIS)
Ludwig, Michelle S.; McNeese, Marsha D.; Buchholz, Thomas A.; Perkins, George H.; Strom, Eric A.
2010-01-01
Purpose: To describe and evaluate the modified lateral decubitus boost, a breast irradiation technique. Patients are repositioned and resimulated for electron boost to minimize the necessary depth for the electron beam and optimize target volume coverage. Methods and Materials: A total of 2,606 patients were treated with post-lumpectomy radiation at our institution between January 1, 2000, and February 1, 2008. Of these, 231 patients underwent resimulation in the lateral decubitus position with electron boost. Distance from skin to the maximal depth of target volume was measured in both the original and boost plans. Age, body mass index (BMI), boost electron energy, and skin reaction were evaluated. Results: Resimulation in the lateral decubitus position reduced the distance from skin to maximal target volume depth in all patients. Average depth reduction by repositioning was 2.12 cm, allowing for an average electron energy reduction of approximately 7 MeV. Mean skin entrance dose was reduced from about 90% to about 85% (p < 0.001). Only 14 patients (6%) experienced moist desquamation in the boost field at the end of treatment. Average BMI of these patients was 30.4 (range, 17.8-50.7). BMI greater than 30 was associated with more depth reduction by repositioning and increased risk of moist desquamation. Conclusions: The lateral decubitus position allows for a decrease in the distance from the skin to the target volume depth, improving electron coverage of the tumor bed while reducing skin entrance dose. This is a well-tolerated regimen for a patient population with a high BMI or deep tumor location.
DEFF Research Database (Denmark)
Lillemark, Marie Rathcke; Gerstoft, Jan; Obel, Niels
2011-01-01
The use of highly active antiretroviral treatment (HAART) regimens with unboosted protease inhibitors (PIs) has resulted in a high level of virological failure primarily due to the development of resistant virus. Current boosted PI regimens combine successfully low-dose ritonavir (r) with a second...... PI. The aim of the study was to estimate the proportion of patients, in a population based setting, who develop virological failure on a PI/r regimen. Through The Danish HIV Cohort Study 1,007 patients who received PI/r based treatment between 1995 and 2008 were identified. Twenty-three (2.......3%) experienced virological failure, of whom 19 (83%) started PI/r treatment before 2001. Patients from Copenhagen (n=19) were selected to study the development of protease (PR) and gag cleavage site (CS) mutations during PI/r treatment and PI plasma levels at the time of virological failure. Three patients (16...
Boosted Objects: A Probe of Beyond the Standard Model Physics
Energy Technology Data Exchange (ETDEWEB)
Abdesselam, A.; /Oxford U.; Kuutmann, E.Bergeaas; /DESY; Bitenc, U.; /Freiburg U.; Brooijmans, G.; /Columbia U.; Butterworth, J.; /University Coll. London; Bruckman de Renstrom, P.; /Cracow, INP; Buarque Franzosi, D.; /Turin U.; Buckingham, R.; /Oxford U.; Chapleau, B.; /McGill U.; Dasgupta, M.; /Manchester U.; Davison, A.; /University Coll. London; Dolen, J.; /UC, Davis; Ellis, S.; /Washington U., Seattle; Fassi, F.; /Lyon, IPN; Ferrando, J.; /Oxford U.; Frandsen, M.T.; /Oxford U.; Frost, J.; /Cambridge U.; Gadfort, T.; /Brookhaven; Glover, N.; /Durham U.; Haas, A.; /SLAC; Halkiadakis, E.; /Rutgers U., Piscataway /INFN, Milan Bicocca /Oxford U. /Ohio State U. /Rutherford /Oxford U. /Oxford U. /Maryland U. /Bristol U. /Princeton U. /Oxford U. /Oxford U. /Arizona U. /Johns Hopkins U. /Oxford U. /Fermilab /Rutherford /Bristol U. /Karlsruhe U., EKP /Weizmann Inst. /Washington U., Seattle /Johns Hopkins U. /Oslo U. /Durham U. /Princeton U. /Paris, LPTHE /CERN /Southern Denmark U., CP3-Origins /Granada U. /SLAC /Rutherford /Toronto U. /Stockholm U., OKC /Stockholm U. /Yale U.; /more authors..
2012-06-12
We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.
A Two-Stage Wind Grid Inverter with Boost Converter
Che, Yanbo; Zhang, Wen; Ge, Leijiao; Zhang, Jijie
2014-01-01
At present, the conversion efficiency of commercial small wind grid inverter is low, and, in case of low wind speed, the wind energy cannot be used efficiently. In order to resolve this problem, it is necessary to improve the topological structure and control strategy, and design a new small wind grid inverter. In this paper, we apply a two-voltage stage topology with boost converter. The boost circuit is to achieve the maximum power output of the wind energy by the segmented regulation, whil...
Boosted objects: a probe of beyond the Standard Model physics
Abdesselam, A; Bitenc, U; Brooijmans, G; Butterworth, J; Bruckman de Renstrom, P; Buarque Franzosi, D; Buckingham, R; Chapleau, B; Dasgupta, M; Davison, A; Dolen, J; Ellis, S; Fassi, F; Ferrando, J; Frandsen, M T; Frost, J; Gadfort, T; Glover, N; Haas, A; Halkiadakis, E; Hamilton, K; Hays, C; Hill, C; Jackson, J; Issever, C; Karagoz, M; Katz, A; Kreczko, L; Krohn, D; Lewis, A; Livermore, S; Loch, P; Maksimovic, P; March-Russell, J; Martin, A; McCubbin, N; Newbold, D; Ott, J; Perez, G; Policchio, A; Rappoccio, S; Raklev, A R; Richardson, P; Salam, G P; Sannino, F; Santiago, J; Schwartzman, A; Shepherd-Themistocleous, C; Sinervo, P; Sjoelin, J; Son, M; Spannowsky, M; Strauss, E; Takeuchi, M; Tseng, J; Tweedie, B; Vermillion, C; Voigt, J; Vos, M; Wacker, J; Wagner-Kuhr, J; Wilson, M G
2011-01-01
We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.
Zhu, Wandi; Pewin, Winston; Wang, Chao; Luo, Yuan; Gonzalez, Gilbert X; Mohan, Teena; Prausnitz, Mark R; Wang, Bao-Zhong
2017-09-10
The biodegradable microneedle patch (MNP) is a novel technology for vaccine delivery that could improve the immunogenicity of vaccines. To broaden the protective efficiency of conventional influenza vaccines, a new 4M2e-tFliC fusion protein construct containing M2e sequences from different subtypes was generated. Purified fusion protein was encapsulate into MNPs with a biocompatible polymer for use as a boosting vaccine. The results demonstrated that mice receiving a conventional inactivated vaccine followed by a skin-applied dissolving 4M2e-tFliC MNP boost could better maintain the humoral antibody response than that by the conventional vaccine-prime alone. Compared with an intramuscular injection boost, mice receiving the MNP boost showed significantly enhanced cellular immune responses, hemagglutination-inhibition (HAI) titers, and neutralization titers. Increased frequency of antigen-specific plasma cells and long-lived bone marrow plasma cells was detected in the MNP boosted group as well, indicating that skin vaccination with 4M2e-tFliC facilitated a long-term antibody-mediated immunity. The 4M2e-tFliC MNP-boosted group also possessed enhanced protection against high lethal dose challenges against homologous A/PR/8/34 and A/Aichi/2/68 viruses and protection for a majority of immunized mice against a heterologous A/California/07/2009 H1N1 virus. High levels of M2e specific immune responses were observed in the 4M2e-tFliC MNP-boosted group as well. These results demonstrate that a skin-applied 4M2e-tFliC MNP boosting immunization to seasonal vaccine recipients may be a rapid approach for increasing the protective efficacy of seasonal vaccines in response to a significant drift seen in circulating viruses. The results also provide a new perspective for future exploration of universal influenza vaccines. Copyright © 2017 Elsevier B.V. All rights reserved.
A quantization scheme for scale-invariant pure gauge theories
International Nuclear Information System (INIS)
Hortacsu, M.
1988-01-01
A scheme is suggested for the quantization of the recently proposed scale-invariant gauge theories in higher dimensions. The model is minimally coupled to a spinor field. Regularization algorithms are proposed. (orig.)
Gauge-invariant two- and three- density correlators
Alexandrou, C; Tsapalis, A; Forcrand, Ph. de
2003-01-01
Gauge-invariant spatial correlations between two and three quarks inside a hadron are measured within quenched and unquenched QCD. These correlators provide information on the shape and multipole moments of the pion, the rho, the nucleon and the $\\Delta$.
About Shape Identification Methods of Objects Invariant to Projective Transformations
Directory of Open Access Journals (Sweden)
Gostev Ivan M.
2016-01-01
Full Text Available Diffculties concerning the choice of the invariants of the projective transformation groups used for the identification of the shapes of planar objects are illustrated and solutions allowing the derivation of robust identification criteria are discussed.
Linear Invariant Tensor Interpolation Applied to Cardiac Diffusion Tensor MRI
Gahm, Jin Kyu; Wisniewski, Nicholas; Kindlmann, Gordon; Kung, Geoffrey L.; Klug, William S.; Garfinkel, Alan; Ennis, Daniel B.
2015-01-01
Purpose Various methods exist for interpolating diffusion tensor fields, but none of them linearly interpolate tensor shape attributes. Linear interpolation is expected not to introduce spurious changes in tensor shape. Methods Herein we define a new linear invariant (LI) tensor interpolation method that linearly interpolates components of tensor shape (tensor invariants) and recapitulates the interpolated tensor from the linearly interpolated tensor invariants and the eigenvectors of a linearly interpolated tensor. The LI tensor interpolation method is compared to the Euclidean (EU), affine-invariant Riemannian (AI), log-Euclidean (LE) and geodesic-loxodrome (GL) interpolation methods using both a synthetic tensor field and three experimentally measured cardiac DT-MRI datasets. Results EU, AI, and LE introduce significant microstructural bias, which can be avoided through the use of GL or LI. Conclusion GL introduces the least microstructural bias, but LI tensor interpolation performs very similarly and at substantially reduced computational cost. PMID:23286085
Gauge field improvement, form-scalar duality and conformal invariance
Deser, Stanley
1994-01-01
The problem of maintaining scale and conformal invariance in Maxwell and general N-form gauge theories away from their critical dimension d=2(N+1) is analyzed.We first exhibit the underlying group-theoretical clash between locality,gauge,Lorentz and conformal invariance require- ments. "Improved" traceless stress tensors are then constructed;each violates one of the above criteria.However,when d=N+2,there is a duality equivalence between N-form models and massless scalars.Here we show that conformal invariance is not lost,by constructing a quasilocal gauge invariant improved stress tensor.The correlators of the scalar theory are then reproduced including the latter's trace anomaly.
Chiral gauge theories on the lattice with exact gauge invariance
Lüscher, Martin
1999-01-01
A recently proposed formulation of chiral lattice gauge theories is reviewed, in which the locality and gauge invariance of the theory can be preserved if the fermion representation of the gauge group is anomaly-free.
Canopy spectral invariants for remote sensing and model applications
Huang, D.; Knyazikhin, Y.; Dickinson, R.E.; Rautiainen, M.; Stenberg, P.; Disney, M.; Lewis, P.; Cescatti, A.; Tian, Y.; Verhoef, W.; Martonchik, J.V.; Myneni, R.B.
2007-01-01
The concept of canopy spectral invariants expresses the observation that simple algebraic combinations of leaf and canopy spectral transmittance and reflectance become wavelength independent and determine a small set of canopy structure specific variables. This set includes the canopy interceptance,
The component structure of conformal supergravity invariants in six dimensions
Butter, Daniel; Novak, Joseph; Tartaglino-Mazzucchelli, Gabriele
2017-05-01
In the recent paper arXiv:1606.02921, the two invariant actions for 6D N=(1,0) conformal supergravity were constructed in superspace, corresponding to the supersymmetrization of C 3 and C□ C. In this paper, we provide the translation from superspace to the component formulation of superconformal tensor calculus, and we give the full component actions of these two invariants. As a second application, we build the component form for the supersymmetric F□ F action coupled to conformal supergravity. Exploiting the fact that the N=(2,0) Weyl multiplet has a consistent truncation to N=(1,0), we then verify that there is indeed only a single N=(2,0) conformal supergravity invariant and reconstruct most of its bosonic terms by uplifting a certain linear combination of N=(1,0) invariants.
Invariance properties of the Dirac equation with external electro ...
Indian Academy of Sciences (India)
. Introduction. The objective of this short paper is to investigate the invariance properties of the Dirac equation with external electro-magnetic field. There exists a large number of literatures on the problem beginning almost from the formulation ...
Generalized N-coupled maps with invariant measure in Bose ...
Indian Academy of Sciences (India)
- bility of the ..... One-parameter families of chaotic maps of the interval [0, ...... their invariant measure and Lyapunov exponent in order to simplify the generation of coupled map model based on Bose–Mesner algebra: 1. Bernuli shift map:.
Inertial Spontaneous Symmetry Breaking and Quantum Scale Invariance
Energy Technology Data Exchange (ETDEWEB)
Ferreira, Pedro G. [Oxford U.; Hill, Christopher T. [Fermilab; Ross, Graham G. [Oxford U., Theor. Phys.
2018-01-23
Weyl invariant theories of scalars and gravity can generate all mass scales spontaneously, initiated by a dynamical process of "inertial spontaneous symmetry breaking" that does not involve a potential. This is dictated by the structure of the Weyl current, $K_\\mu$, and a cosmological phase during which the universe expands and the Einstein-Hilbert effective action is formed. Maintaining exact Weyl invariance in the renormalised quantum theory is straightforward when renormalisation conditions are referred back to the VEV's of fields in the action of the theory, which implies a conserved Weyl current. We do not require scale invariant regulators. We illustrate the computation of a Weyl invariant Coleman-Weinberg potential.
Manifestly scale-invariant regularization and quantum effective operators
Ghilencea, D.M.
2016-01-01
Scale invariant theories are often used to address the hierarchy problem, however the regularization of their quantum corrections introduces a dimensionful coupling (dimensional regularization) or scale (Pauli-Villars, etc) which break this symmetry explicitly. We show how to avoid this problem and study the implications of a manifestly scale invariant regularization in (classical) scale invariant theories. We use a dilaton-dependent subtraction function $\\mu(\\sigma)$ which after spontaneous breaking of scale symmetry generates the usual DR subtraction scale $\\mu(\\langle\\sigma\\rangle)$. One consequence is that "evanescent" interactions generated by scale invariance of the action in $d=4-2\\epsilon$ (but vanishing in $d=4$), give rise to new, finite quantum corrections. We find a (finite) correction $\\Delta U(\\phi,\\sigma)$ to the one-loop scalar potential for $\\phi$ and $\\sigma$, beyond the Coleman-Weinberg term. $\\Delta U$ is due to an evanescent correction ($\\propto\\epsilon$) to the field-dependent masses (of...
Trace anomaly and invariance under transformation of units
Namavarian, Nadereh
2017-05-01
Paying attention to conformal invariance as the invariance under local transformations of units of measure, we take a conformal-invariant quantum field as a quantum matter theory in which one has the freedom to choose the values of units of mass, length, and time arbitrarily at each point. To be able to have this view, it is necessary that the background on which the quantum field is based be conformal invariant as well. Consequently, defining the unambiguous expectation value of the energy-momentum tensor of such a quantum field through the Wald renormalizing prescription necessitates breaking down the conformal symmetry of the background. Then, noticing the field equations suitable for describing the backreaction effect, we show that the existence of the "trace anomaly," known for indicating the brokenness of conformal symmetry in quantum field theory, can also indicate the above "gravitational" conformal symmetry brokenness.
Testing measurement invariance of composites using partial least squares
Henseler, Jörg; Ringle, Christian M.; Sarstedt, Marko
2016-01-01
Purpose Research on international marketing usually involves comparing different groups of respondents. When using structural equation modeling (SEM), group comparisons can be misleading unless researchers establish the invariance of their measures. While methods have been proposed to analyze
Construction of exact complex dynamical invariant of a two ...
Indian Academy of Sciences (India)
dimensional classical dynamical system on an extended complex space utilizing Lie algebraic approach. These invariants are expected to play a vital role in understanding the complex trajectories of both classical and quantum systems.
Wavelet subspaces invariant under groups of translation operators
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
Tα(Vj ) ⊂ Vj for all j ∈ Z and for all α ∈ R. Madych proved that the only translation invariant MRAs are those for which the Fourier transform of the scaling function is the characteristic function of a set. In other words, the associated wavelet is an MSF wavelet. Walter [10,11] modified the definition of translation invariance to ...
Construction of Lie algebras and invariant tensors through abelian semigroups
International Nuclear Information System (INIS)
Izaurieta, Fernando; RodrIguez, Eduardo; Salgado, Patricio
2008-01-01
The Abelian Semigroup Expansion Method for Lie Algebras is briefly explained. Given a Lie Algebra and a discrete abelian semigroup, the method allows us to directly build new Lie Algebras with their corresponding non-trivial invariant tensors. The Method is especially interesting in the context of M-Theory, because it allows us to construct M-Algebra Invariant Chern-Simons/Transgression Lagrangians in d = 11.
Skewed base compositions, asymmetric transition matrices, and phylogenetic invariants.
Ferretti, V; Lang, B F; Sankoff, D
1994-01-01
Evolutionary inference methods that assume equal DNA base compositions and symmetric nucleotide substitution matrices, where these assumptions do not hold, are likely to group species on the basis of similar base compositions rather than true phylogenetic relationships. We propose an invariants-based method for dealing with this problem. An invariant QT of a tree T under a k-state Markov model, where a generalized time parameter is identified with the E edges of T, allows us to recognize whether data on N observed species can be associated with the N terminal vertices of T in the sense of having been generated on T rather than on any other tree with N terminals. The form of the generalized time parameter is a positive determinant matrix in some semigroup S of stochastic matrices. The invariance is with respect to the choice of the set of E matrices in S, one associated with each of the E edges of T. We apply a general "empirical" method of finding invariants of a parametrized functional form. It involves calculating the probability f of all KN data possibilities for each of m sets of E matrices in S to associate with the edges of T, then solving for the parameters using the m equations of form Q(f) = 0. We discuss the problems of finding asymmetric models satisfying the property of semigroup closure, of finding asymmetric models that admit invariants at all, and of the computational complexity of the method. We propose a class of semigroups Sc containing matrices of form [formula: see text] to account for A+T versus G+C asymmetries in DNA base composition. Quadratic invariants are obtained for rooted trees with three and with four terminals. In the latter case the smallest set of algebraically independent invariants is sought. These invariants are applied to data pertaining the fungal evolution and to the origin of mitochondria as bacterial endosymbionts.
RG Cycles, Scale vs Conformal Invariance, and All That...
Fortin, J.-F.; Grinstein, B.; Stergiou, A.
Two long-standing questions in Quantum Field Theory have been recently answered, at least in perturbation theory. The first one is, are there recursive flows as solutions of the renormalization group equation (answer: yes). The second one is, can a theory display invariance under dilatations but not be conformally invariant? (answer: no). We review these results. In so doing we give a hopefully pedagogic derivation of the trace anomaly equation and of the Weyl consistency conditions of Jack and Osborn.
Modular invariant partition functions for toroidally compactified bosonic string
International Nuclear Information System (INIS)
Ardalan, F.; Arfaei, H.
1988-06-01
We systematically find all the modular invariant partition functions for the toroidally compactified closed bosonic string defined on a subset of a simply laced simple Lie algebra lattice, or equivalently for the closed bosonic string moving on a group manifold with the WZW coefficient k=1. We examine the relation between modular invariance of partition function and the possibility of describing it by an even Lorentzian self dual lattice in our context. (author). 23 refs
Rotation invariants from Gaussian-Hermite moments of color images
Czech Academy of Sciences Publication Activity Database
Yang, B.; Suk, Tomáš; Flusser, Jan; Shi, Z.; Chen, X.
2018-01-01
Roč. 143, č. 1 (2018), s. 282-291 ISSN 0165-1684 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : Color images * Object recognition * Rotation invariants * Gaussian–Hermite moments * Joint invariants Subject RIV: JD - Computer Applications, Robotics Impact factor: 3.110, year: 2016 http://library.utia.cas.cz/separaty/2017/ZOI/suk-0479748. pdf
Gender invariance of the College Student Stress Scale.
Feldt, Ronald C; Updegraff, Christina
2013-10-01
Assessment of perceived stress may be an important prerequisite to deployment of effective coping in efforts to help college students adjust to academic and social demands of college. The study examined the extent to which a seven-item measure of the College Student Stress Scale is invariant across gender. Results indicated invariance of factor loadings, factor variance, and all but one item intercept. No statistically significant gender difference was observed between latent variable means.
Are the invariance principles really truly Lorentz covariant?
International Nuclear Information System (INIS)
Arunasalam, V.
1994-02-01
It is shown that some sections of the invariance (or symmetry) principles such as the space reversal symmetry (or parity P) and time reversal symmetry T (of elementary particle and condensed matter physics, etc.) are not really truly Lorentz covariant. Indeed, I find that the Dirac-Wigner sense of Lorentz invariance is not in full compliance with the Einstein-Minkowski reguirements of the Lorentz covariance of all physical laws (i.e., the world space Mach principle)
The supersymmetric t-J model with quantum group invariance
International Nuclear Information System (INIS)
Foerster, A.; Karowski, M.
1993-04-01
An integrable quantum group deformation of the supersymmetric t-J model is introduced. Open boundary conditions lead to an spl q (2, 1) invariant hamiltonian. A general procedure to obtain such invariant models is proposed. To solve the model a generalized nested algebraic Bethe ansatz is constructed and the Bethe ansatz equations are obtained. The quantum supergroup structure of the model is investigated. (orig.)
Modular invariants from simple currents. An explicit proof
International Nuclear Information System (INIS)
Schellekens, A.N.; Yankielowicz, S.
1989-01-01
In a previous paper an orbifold construction was used to demonstrate that the existence of primary fields with simple fusion rules in a conformal field theory implies the existence of non-diagonal modular invariant partition functions. Here we present a direct and explicit proof of modular invariance, which also covers a few cases that could not be obtained with the orbifold method. We also give a very simple general formula for the modular matrix M. (orig.)
QCD, monopoles on the lattice and gauge invariance
International Nuclear Information System (INIS)
Bonati, C.; Di Giacomo, A.; D'Elia, M.
2011-01-01
The number and the location of the monopoles observed on the lattice in QCD configurations happens to depend strongly on the choice of the gauge used to expose them, in contrast to the physical expectation that monopoles be gauge invariant objects. It is proved by use of the non abelian Bianchi identities (NABI) that monopoles are indeed gauge invariant, but the method used to detect them depends, in a controllable way, on the choice of the abelian projection. Numerical checks are presented.
Observation of the Efimovian Expansion in Scale Invariant Fermi Gases
Deng, Shujin; Shi, Zhe-Yu; Diao, Pengpeng; Yu, Qianli; Zhai, Hui; Qi, Ran; Wu, Haibin
2015-01-01
Scale invariance emerges and plays an important role in strongly correlated many-body systems such as critical regimes nearby phase transitions and the unitary Fermi gases. Discrete scaling symmetry also manifests itself in quantum few-body systems such as the Efimov effect. Here we report both theoretical predication and experimental observation of a novel type expansion dynamics for scale invariant quantum gases. When the frequency of the harmonic trap holding the gas decreases continuously...
3D rotation invariants of Gaussian-Hermite moments
Czech Academy of Sciences Publication Activity Database
Yang, Bo; Flusser, Jan; Suk, Tomáš
2015-01-01
Roč. 54, č. 1 (2015), s. 18-26 ISSN 0167-8655 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : Rotation invariants * Orthogonal moments * Gaussian–Hermite moments * 3D moment invariants Subject RIV: IN - Informatics, Computer Science Impact factor: 1.586, year: 2015 http://library.utia.cas.cz/separaty/2014/ZOI/yang-0438325.pdf
Invariance as a Tool for Ontology of Information
Directory of Open Access Journals (Sweden)
Marcin J. Schroeder
2016-03-01
Full Text Available Attempts to answer questions regarding the ontological status of information are frequently based on the assumption that information should be placed within an already existing framework of concepts of established ontological statuses related to science, in particular to physics. However, many concepts of physics have undetermined or questionable ontological foundations. We can look for a solution in the recognition of the fundamental role of invariance with respect to a change of reference frame and to other transformations as a criterion for objective existence. The importance of invariance (symmetry as a criterion for a primary ontological status can be identified in the methodology of physics from its beginnings in the work of Galileo, to modern classifications of elementary particles. Thus, the study of the invariance of the theoretical description of information is proposed as the first step towards ontology of information. With the exception of only a few works among publications which set the paradigm of information studies, the issues of invariance were neglected. Orthodox analysis of information lacks conceptual framework for the study of invariance. The present paper shows how invariance can be formalized for the definition of information and, accompanying it, mathematical formalism proposed by the author in his earlier publications.
Adiabatic invariants of the extended KdV equation
Energy Technology Data Exchange (ETDEWEB)
Karczewska, Anna [Faculty of Mathematics, Computer Science and Econometrics, University of Zielona Góra, Szafrana 4a, 65-246 Zielona Góra (Poland); Rozmej, Piotr, E-mail: p.rozmej@if.uz.zgora.pl [Institute of Physics, Faculty of Physics and Astronomy, University of Zielona Góra, Szafrana 4a, 65-246 Zielona Góra (Poland); Infeld, Eryk [National Centre for Nuclear Research, Hoża 69, 00-681 Warszawa (Poland); Rowlands, George [Department of Physics, University of Warwick, Coventry, CV4 7A (United Kingdom)
2017-01-30
When the Euler equations for shallow water are taken to the next order, beyond KdV, momentum and energy are no longer exact invariants. (The only one is mass.) However, adiabatic invariants (AI) can be found. When the KdV expansion parameters are zero, exact invariants are recovered. Existence of adiabatic invariants results from general theory of near-identity transformations (NIT) which allow us to transform higher order nonintegrable equations to asymptotically equivalent (when small parameters tend to zero) integrable form. Here we present a direct method of calculations of adiabatic invariants. It does not need a transformation to a moving reference frame nor performing a near-identity transformation. Numerical tests show that deviations of AI from constant values are indeed small. - Highlights: • We suggest a new and simple method for calculating adiabatic invariants of second order wave equations. • It is easy to use and we hope that it will be useful if published. • Interesting numerics included.
Quantum tunneling, adiabatic invariance and black hole spectroscopy
Li, Guo-Ping; Pu, Jin; Jiang, Qing-Quan; Zu, Xiao-Tao
2017-05-01
In the tunneling framework, one of us, Jiang, together with Han has studied the black hole spectroscopy via adiabatic invariance, where the adiabatic invariant quantity has been intriguingly obtained by investigating the oscillating velocity of the black hole horizon. In this paper, we attempt to improve Jiang-Han's proposal in two ways. Firstly, we once again examine the fact that, in different types (Schwarzschild and Painlevé) of coordinates as well as in different gravity frames, the adiabatic invariant I_adia = \\oint p_i dq_i introduced by Jiang and Han is canonically invariant. Secondly, we attempt to confirm Jiang-Han's proposal reasonably in more general gravity frames (including Einstein's gravity, EGB gravity and HL gravity). Concurrently, for improving this proposal, we interestingly find in more general gravity theories that the entropy of the black hole is an adiabatic invariant action variable, but the horizon area is only an adiabatic invariant. In this sense, we emphasize the concept that the quantum of the black hole entropy is more natural than that of the horizon area.
Quantum tunneling, adiabatic invariance and black hole spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Li, Guo-Ping; Zu, Xiao-Tao [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Pu, Jin [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); China West Normal University, College of Physics and Space Science, Nanchong (China); Jiang, Qing-Quan [China West Normal University, College of Physics and Space Science, Nanchong (China)
2017-05-15
In the tunneling framework, one of us, Jiang, together with Han has studied the black hole spectroscopy via adiabatic invariance, where the adiabatic invariant quantity has been intriguingly obtained by investigating the oscillating velocity of the black hole horizon. In this paper, we attempt to improve Jiang-Han's proposal in two ways. Firstly, we once again examine the fact that, in different types (Schwarzschild and Painleve) of coordinates as well as in different gravity frames, the adiabatic invariant I{sub adia} = circular integral p{sub i}dq{sub i} introduced by Jiang and Han is canonically invariant. Secondly, we attempt to confirm Jiang-Han's proposal reasonably in more general gravity frames (including Einstein's gravity, EGB gravity and HL gravity). Concurrently, for improving this proposal, we interestingly find in more general gravity theories that the entropy of the black hole is an adiabatic invariant action variable, but the horizon area is only an adiabatic invariant. In this sense, we emphasize the concept that the quantum of the black hole entropy is more natural than that of the horizon area. (orig.)
International Nuclear Information System (INIS)
Horton, W.
1998-07-01
The origin of plasma turbulence from currents and spatial gradients in plasmas is described and shown to lead to the dominant transport mechanism in many plasma regimes. A wide variety of turbulent transport mechanism exists in plasmas. In this survey the authors summarize some of the universally observed plasma transport rates
Boosted jet identification using particle candidates and deep neural networks
CMS Collaboration
2017-01-01
This note presents developments for the identification of hadronically decaying top quarks using deep neural networks in CMS. A new method that utilizes one dimensional convolutional neural networks based on jet constituent particles is proposed. Alternative methods using boosted decision trees based on jet observables are compared. The new method shows significant improvement in performance.
Integrated Current Balancing Transformer for Primary Parallel Isolated Boost Converter
DEFF Research Database (Denmark)
Sen, Gökhan; Ouyang, Ziwei; Thomsen, Ole Cornelius
2011-01-01
A simple, PCB compatible integrated solution is proposed for the current balancing requirement of the primary parallel isolated boost converter (PPIBC). Input inductor and the current balancing transformer are merged into the same core, which reduces the number of components allowing a cheaper an...
Biochar boosts tropical but not temperate crop yields
Jeffery, Simon; Abalos Rodriguez, Diego; Prodana, Marija; Bastos, Ana Catarina; Groenigen, van Jan Willem; Hungate, Bruce A.; Verheijen, Frank
2017-01-01
Applying biochar to soil is thought to have multiple benefits, from helping mitigate climate change [1, 2], to managing waste [3] to conserving soil [4]. Biochar is also widely assumed to boost crop yield [5, 6], but there is controversy regarding the extent and cause of any yield benefit [7].
Solar-Based Boost Differential Single Phase Inverter | Eya | Nigerian ...
African Journals Online (AJOL)
... current concurrently and finally, it is portable. This research also shows the disparity between the simulated results of open loop and closed loop of boost differential inverter systems. The dc power source is photovoltaic cell. The maximum power point tracker is in-cooperated in capturing the maximum power from the sun.
Boosting food security in sub-Saharan Africa through cassava ...
African Journals Online (AJOL)
Boosting food security in sub-Saharan Africa through cassava production: a case study of Nigeria. ... Nigerian Journal of Economic History ... The paper argues that cassava which is widely grown in Sub-Saharan Africa with a lot of variety of food derivatives from it can reduce to the barest minimum the present state of food ...
HIV-prevention studies: Educate smarter, boost women's earning ...
African Journals Online (AJOL)
the 'very hard-to-reach' youth of informal settlements countrywide. 'Although it was done in a small community, we need to think of feasible ways in which we can ... strewn about below the condocans, perhaps indicating the community's. HIV-prevention studies: Educate smarter, boost women's earning power. Professor ...
Adaptive Kernel in Meshsize Boosting Algorithm in KDE ...
African Journals Online (AJOL)
This paper proposes the use of adaptive kernel in a meshsize boosting algorithm in kernel density estimation. The algorithm is a bias reduction scheme like other existing schemes but uses adaptive kernel instead of the regular fixed kernels. An empirical study for this scheme is conducted and the findings are comparatively ...
Adaptive Kernel In The Bootstrap Boosting Algorithm In KDE ...
African Journals Online (AJOL)
This paper proposes the use of adaptive kernel in a bootstrap boosting algorithm in kernel density estimation. The algorithm is a bias reduction scheme like other existing schemes but uses adaptive kernel instead of the regular fixed kernels. An empirical study for this scheme is conducted and the findings are comparatively ...
Congress OKs $2 Billion Boost for the NIH.
2017-07-01
President Donald Trump last week signed a $1.1 trillion spending bill for fiscal year 2017, including a welcome $2 billion boost for the NIH that will support former Vice President Joe Biden's Cancer Moonshot initiative, among other priorities. However, researchers who rely heavily on NIH grant funding remain concerned about proposed cuts for 2018. ©2017 American Association for Cancer Research.
Higher-Order Hybrid Gaussian Kernel in Meshsize Boosting Algorithm
African Journals Online (AJOL)
In this paper, we shall use higher-order hybrid Gaussian kernel in a meshsize boosting algorithm in kernel density estimation. Bias reduction is guaranteed in this scheme like other existing schemes but uses the higher-order hybrid Gaussian kernel instead of the regular fixed kernels. A numerical verification of this scheme ...
A THREE-PHASE BOOST DC-AC CONVERTER
African Journals Online (AJOL)
- strate the feasibility of the proposed three-phase inverter. The inverter is intended to be used in three-phase electric drives and uninterruptible power supply (UPS) systems. Keywords: Boost converter, three-phase dc-ac converter, sliding ...
Multistage switched inductor boost converter for renewable energy application
DEFF Research Database (Denmark)
Maroti, Pandav Kiran; Padmanaban, Sanjeevikumar; Bhaskar, Mahajan Sagar
2017-01-01
In this paper Multistage Switched Inductor Boost Converter (Multistage SIBC) is uttered for renewable energy applications. The projected converter is derived from an amalgamation of the conventional step-up converter and inductor stack. The number of inductor and duty ratio decides the overall...
Primary Parallel Isolated Boost Converter with Bidirectional Operation
DEFF Research Database (Denmark)
Hernandez Botella, Juan Carlos; Mira Albert, Maria del Carmen; Sen, Gökhan
2012-01-01
This paper presents a bidirectional dc/dc converter operated with batteries both in the input and output. Primary parallel isolated boost converter (PPIBC) with transformer series connection on the high voltage side is preferred due to its ability to handle high currents in the low voltage side...
Boost IORT in Breast Cancer: Body of Evidence
Directory of Open Access Journals (Sweden)
Felix Sedlmayer
2014-01-01
Full Text Available The term IORT (intraoperative radiotherapy is currently used for various techniques that show decisive differences in dose delivery. The largest evidence for boost IORT preceding whole breast irradiation (WBI originates from intraoperative electron treatments with single doses around 10 Gy, providing outstandingly low local recurrence rates in any risk constellation also at long term analyses. Compared to other boost methods, an intraoperative treatment has evident advantages as follows. Precision. Direct visualisation of the tumour bed during surgery guarantees an accurate dose delivery. This fact has additionally gained importance in times of primary reconstruction techniques after lumpectomy to optimise cosmetic outcome. IORT is performed before breast tissue is mobilised for plastic purposes. Cosmesis. As a consequence of direct tissue exposure without distension by hematoma/seroma, IORT allows for small treatment volumes and complete skin sparing, both having a positive effect on late tissue tolerance and, hence, cosmetic appearance. Patient Comfort. Boost IORT marginally prolongs the surgical procedure, while significantly shortening postoperative radiotherapy. Its combination with a 3-week hypofractionated external beam radiotherapy to the whole breast (WBI is presently tested in the HIOB trial (hypofractionated WBI preceded by IORT electron boost, a prospective multicenter trial of the International Society of Intraoperative Radiotherapy (ISIORT.
Tricky treats: how and when temptations boost self-control
Kroese, F.M.|info:eu-repo/dai/nl/313869871
2012-01-01
The overall aim of this dissertation was to explore how and when temptations boost self-control. More specifically, we aimed to a) replicate and extend previous findings showing that temptations yield enhanced self-control on cognitive as well as behavioral measures; b) examine the role of
438 Adaptive Kernel in Meshsize Boosting Algorithm in KDE (Pp ...
African Journals Online (AJOL)
FIRST LADY
2011-01-18
Jan 18, 2011 ... Birke, Melanie (2009). “Shape constrained KDE.” Journal of Statistical. Planning & Inference, vol 139, issue 8 , August 2009, pg 2851 –. 2862. Duffy, N. and Hemlbold, D. (2000). “Potential bosters? Advances in Neural info.” Proc. Sys. 12, 258 – 264. Freund, Y. (1995). “Boosting a Weak Learning Algorithm ...
Search for new resonances with boosted signatures at CMS
CERN. Geneva
2015-01-01
The LHC and its experiments are ideally suited to search for these new resonances in order to validate or constrain the corresponding theories. At resonance masses well above 1 TeV, these searches face specific challenges. The decay products have large Lorentz boosts, resulting in very collimated final state topologies. Jet substructure methods and the use of non-isolate...
Modeling and Control of Primary Parallel Isolated Boost Converter
DEFF Research Database (Denmark)
Mira Albert, Maria del Carmen; Hernandez Botella, Juan Carlos; Sen, Gökhan
2012-01-01
In this paper state space modeling and closed loop controlled operation have been presented for primary parallel isolated boost converter (PPIBC) topology as a battery charging unit. Parasitic resistances have been included to have an accurate dynamic model. The accuracy of the model has been...
International Nuclear Information System (INIS)
Weitzner, H.
1990-06-01
This paper discusses the following topics: MHD plasma activity: equilibrium, stability and transport; statistical analysis; transport studies; edge physics studies; wave propagation analysis; basic plasma physics and fluid dynamics; space plasma; and numerical methods
Wide Temperature Range DC-DC Boost Converters for Command/Control/Drive Electronics, Phase I
National Aeronautics and Space Administration — We shall develop wide temperature range DC-DC boost converters that can be fabricated using commercial CMOS foundries. The boost converters will increase the low...
Ganeev, Rashid A
2014-01-01
Preface; Why plasma harmonics? A very brief introduction Early stage of plasma harmonic studies - hopes and frustrations New developments in plasma harmonics studies: first successes Improvements of plasma harmonics; Theoretical basics of plasma harmonics; Basics of HHG Harmonic generation in fullerenes using few-cycle pulsesVarious approaches for description of observed peculiarities of resonant enhancement of a single harmonic in laser plasmaTwo-colour pump resonance-induced enhancement of odd and even harmonics from a tin plasmaCalculations of single harmonic generation from Mn plasma;Low-o
A Survey on Voltage Boosting Techniques for Step-Up DC-DC Converters
DEFF Research Database (Denmark)
Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Gorji, Saman Asghari
2016-01-01
Step-up dc-dc converters are used to boost the voltage level of the input to a higher output level. Despite of its features such as simplicity of implementation, the fundamental boost dc-dc converter has shortcomings such as low boost ability and low power density. With these limitations, researc...
14 CFR 27.695 - Power boost and power-operated control system.
2010-01-01
... Systems § 27.695 Power boost and power-operated control system. (a) If a power boost or power-operated... failure of all engines. (b) Each alternate system may be a duplicate power portion or a manually operated... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Power boost and power-operated control...
14 CFR 29.695 - Power boost and power-operated control system.
2010-01-01
... Systems § 29.695 Power boost and power-operated control system. (a) If a power boost or power-operated... failure of all engines. (b) Each alternate system may be a duplicate power portion or a manually operated... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Power boost and power-operated control...
Multi-clues image retrieval based on improved color invariants
Liu, Liu; Li, Jian-Xun
2012-05-01
At present, image retrieval has a great progress in indexing efficiency and memory usage, which mainly benefits from the utilization of the text retrieval technology, such as the bag-of-features (BOF) model and the inverted-file structure. Meanwhile, because the robust local feature invariants are selected to establish BOF, the retrieval precision of BOF is enhanced, especially when it is applied to a large-scale database. However, these local feature invariants mainly consider the geometric variance of the objects in the images, and thus the color information of the objects fails to be made use of. Because of the development of the information technology and Internet, the majority of our retrieval objects is color images. Therefore, retrieval performance can be further improved through proper utilization of the color information. We propose an improved method through analyzing the flaw of shadow-shading quasi-invariant. The response and performance of shadow-shading quasi-invariant for the object edge with the variance of lighting are enhanced. The color descriptors of the invariant regions are extracted and integrated into BOF based on the local feature. The robustness of the algorithm and the improvement of the performance are verified in the final experiments.
An Advanced Rotation Invariant Descriptor for SAR Image Registration
Directory of Open Access Journals (Sweden)
Yuming Xiang
2017-07-01
Full Text Available The Scale-Invariant Feature Transform (SIFT algorithm and its many variants have been widely used in Synthetic Aperture Radar (SAR image registration. The SIFT-like algorithms maintain rotation invariance by assigning a dominant orientation for each keypoint, while the calculation of dominant orientation is not robust due to the effect of speckle noise in SAR imagery. In this paper, we propose an advanced local descriptor for SAR image registration to achieve rotation invariance without assigning a dominant orientation. Based on the improved intensity orders, we first divide a circular neighborhood into several sub-regions. Second, rotation-invariant ratio orientation histograms of each sub-region are proposed by accumulating the ratio values of different directions in a rotation-invariant coordinate system. The proposed descriptor is composed of the concatenation of the histograms of each sub-region. In order to increase the distinctiveness of the proposed descriptor, multiple image neighborhoods are aggregated. Experimental results on several satellite SAR images have shown an improvement in the matching performance over other state-of-the-art algorithms.
Color-invariant shape moments for object recognition
Zhou, Qiang; Celenk, Mehmet
2001-05-01
Geometric moments have been widely used in many shape recognition and object classification tasks. These monomials are usually computed from binary or gray-level images for the object shape recognition invariant to rotation, translation, and scaling. In this paper, we attempt to calculate the shape related moments from color images, and study their noise immunity and color invariance property for the application areas of face recognition and content based image retrieval. To this end, we describe a computationally efficient method of converting a vector-valued color image into a gray scale for robust moment computation. Geometric moments are calculated from the resultant scalar representation of a color image data, and proven to be robust shape descriptors for the face and flower images. The generated shape invariants appear to have better noise immunity than the Hu moments and exhibit characteristics invariant to hue changes in the object colors. As compared to the Zernike polynomials, the proposed feature set has higher discriminatory power although the Zernike polynomials present superior noise rejection capability. Robust performance, computational efficiency, high noise immunity, and hue invariance property of the new approach are particularly useful for fast image retrieval tasks requiring high query accuracy.
Phylogenetic mixtures and linear invariants for equal input models.
Casanellas, Marta; Steel, Mike
2017-04-01
The reconstruction of phylogenetic trees from molecular sequence data relies on modelling site substitutions by a Markov process, or a mixture of such processes. In general, allowing mixed processes can result in different tree topologies becoming indistinguishable from the data, even for infinitely long sequences. However, when the underlying Markov process supports linear phylogenetic invariants, then provided these are sufficiently informative, the identifiability of the tree topology can be restored. In this paper, we investigate a class of processes that support linear invariants once the stationary distribution is fixed, the 'equal input model'. This model generalizes the 'Felsenstein 1981' model (and thereby the Jukes-Cantor model) from four states to an arbitrary number of states (finite or infinite), and it can also be described by a 'random cluster' process. We describe the structure and dimension of the vector spaces of phylogenetic mixtures and of linear invariants for any fixed phylogenetic tree (and for all trees-the so called 'model invariants'), on any number n of leaves. We also provide a precise description of the space of mixtures and linear invariants for the special case of [Formula: see text] leaves. By combining techniques from discrete random processes and (multi-) linear algebra, our results build on a classic result that was first established by James Lake (Mol Biol Evol 4:167-191, 1987).
Uniqueness of the gauge invariant action for cosmological perturbations
Energy Technology Data Exchange (ETDEWEB)
Prokopec, Tomislav; Weenink, Jan, E-mail: t.prokopec@uu.nl, E-mail: j.g.weenink@uu.nl [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Leuvenlaan 4, 3585 CE Utrecht (Netherlands)
2012-12-01
In second order perturbation theory different definitions are known of gauge invariant perturbations in single field inflationary models. Consequently the corresponding gauge invariant cubic actions do not have the same form. Here we show that the cubic action for one choice of gauge invariant variables is unique in the following sense: the action for any other, non-linearly related variable can be brought to the same bulk action, plus additional boundary terms. These boundary terms correspond to the choice of hypersurface and generate extra, disconnected contributions to the bispectrum. We also discuss uniqueness of the action with respect to conformal frames. When expressed in terms of the gauge invariant curvature perturbation on uniform field hypersurfaces the action for cosmological perturbations has a unique form, independent of the original Einstein or Jordan frame. Crucial is that the gauge invariant comoving curvature perturbation is frame independent, which makes it extremely helpful in showing the quantum equivalence of the two frames, and therefore in calculating quantum effects in nonminimally coupled theories such as Higgs inflation.
Arthur's invariant trace formula and comparison of inner forms
Flicker, Yuval Z
2016-01-01
This monograph provides an accessible and comprehensive introduction to James Arthur’s invariant trace formula, a crucial tool in the theory of automorphic representations. It synthesizes two decades of Arthur’s research and writing into one volume, treating a highly detailed and often difficult subject in a clearer and more uniform manner without sacrificing any technical details. The book begins with a brief overview of Arthur’s work and a proof of the correspondence between GL(n) and its inner forms in general. Subsequent chapters develop the invariant trace formula in a form fit for applications, starting with Arthur’s proof of the basic, non-invariant trace formula, followed by a study of the non-invariance of the terms in the basic trace formula, and, finally, an in-depth look at the development of the invariant formula. The final chapter illustrates the use of the formula by comparing it for G’ = GL(n) and its inner form G and for functions with matching orbital integrals. Arthur’s Invarian...
Robust Frequency Invariant Beamforming with Low Sidelobe for Speech Enhancement
Zhu, Yiting; Pan, Xiang
2018-01-01
Frequency invariant beamformers (FIBs) are widely used in speech enhancement and source localization. There are two traditional optimization methods for FIB design. The first one is convex optimization, which is simple but the frequency invariant characteristic of the beam pattern is poor with respect to frequency band of five octaves. The least squares (LS) approach using spatial response variation (SRV) constraint is another optimization method. Although, it can provide good frequency invariant property, it usually couldn’t be used in speech enhancement for its lack of weight norm constraint which is related to the robustness of a beamformer. In this paper, a robust wideband beamforming method with a constant beamwidth is proposed. The frequency invariant beam pattern is achieved by resolving an optimization problem of the SRV constraint to cover speech frequency band. With the control of sidelobe level, it is available for the frequency invariant beamformer (FIB) to prevent distortion of interference from the undesirable direction. The approach is completed in time-domain by placing tapped delay lines(TDL) and finite impulse response (FIR) filter at the output of each sensor which is more convenient than the Frost processor. By invoking the weight norm constraint, the robustness of the beamformer is further improved against random errors. Experiment results show that the proposed method has a constant beamwidth and almost the same white noise gain as traditional delay-and-sum (DAS) beamformer.
Gauge-invariant three-gluon vertex in QCD
International Nuclear Information System (INIS)
Cornwall, J.M.; Papavassiliou, J.
1989-01-01
By resumming the Feynman graphs which contribute to any gauge-invariant process we explicitly construct, at one-loop order, a three-gluon vertex for QCD which is completely independent of the choice of gauge. This vertex satisfies a Ward identity of the type encountered in ghost-free gauges, relating the vertex to the proper self-energy of a previously constructed gluon propagator, also found by resumming graphs; like the vertex, this self-energy is completely gauge invariant. We also derive the gauge-invariant propagator and vertex via a second related technique which minimizes the dependence on embedding these objects in a gauge-invariant process; the same results are found as in the first technique. These results motivate a toy model of the nonlinear Schwinger-Dyson equation satisfied by the exact gauge-invariant three-gluon vertex. This model is nonperturbative and has infrared singularities, which we can remove via gluon mass generation; it shows many interesting features expected of QCD, such as a β function which is not Borel summable in perturbation theory
Superconformal invariants for scattering amplitudes in N=4 SYM theory
Energy Technology Data Exchange (ETDEWEB)
Korchemsky, G.P., E-mail: korchems@th.u-psud.f [Institut de Physique Theorique, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Sokatchev, E. [LAPTH, Universite de Savoie, CNRS, B.P. 110, F-74941 Annecy-le-Vieux (France)
2010-11-11
Recent studies of scattering amplitudes in planar N=4 SYM theory revealed the existence of a hidden dual superconformal symmetry. Together with the conventional superconformal symmetry it gives rise to powerful restrictions on the planar scattering amplitudes to all loops. We study the general form of the invariants of both symmetries. We first construct an integral representation for the most general dual superconformal invariants and show that it allows a considerable freedom in the choice of the integration measure. We then perform a half-Fourier transform to twistor space, where conventional conformal symmetry is realized locally, derive the resulting conformal Ward identity for the integration measure and show that it admits a unique solution. Thus, the combination of dual and conventional superconformal symmetries, together with invariance under helicity rescalings, completely fixes the form of the invariants. The expressions obtained generalize the known tree and one-loop superconformal invariants and coincide with the recently proposed coefficients of the leading singularities of the scattering amplitudes as contour integrals over Grassmannians.
Concomitant boost radiotherapy for squamous carcinoma of the tonsillar fossa
International Nuclear Information System (INIS)
Gwozdz, John T.; Morrison, William H.; Garden, Adam S.; Weber, Randal S.; Peters, Lester J.; Ang, K. Kian
1997-01-01
Purpose: To assess the efficacy of a concomitant boost fractionation schedule of radiotherapy for treating patients with squamous carcinoma of the tonsillar fossa. Patients and Methods: Between December 1983 and November 1992, 83 patients with squamous carcinoma of the tonsil were treated with concomitant boost fractionation. The distribution of American Joint Committee on Cancer T stages was TX-4, T1-5, T2-29, T3-41, T4-4; N stages were NX-1, N0-26, N1-13, N2-31, N3-12. Patients were treated with standard large fields to 54 Gy in 6 weeks. The boost treatment consisted of a second daily 1.5 Gy fraction for 10-12 fractions, usually delivered during the final phase of treatment. The tumor dose was 69-72 Gy, given over 6 weeks. Twenty-one patients, who all had N2 or N3 regional disease, underwent neck dissections, either before (13 patients) or 6 weeks after radiotherapy (8 patients); the other patients were treated with radiotherapy alone. Results: The 5-year actuarial disease-specific survival and overall survival rates were 71 and 60%, respectively. Patients with T2 and T3 primary tumors had 5-year actuarial local control rates of 96 and 78%, respectively. Patients with T3 disease who received the final-phase boost had a 5-year actuarial local control rate of 82%. Actuarial 5-year regional disease control rates were N0, 92%; N1, 76%; N2, 89%; and N3, 89%. The 21 patients who had neck dissections all had their disease regionally controlled. Patients presenting with nodal disease or after a node excision who were treated with radiation alone had a 5-year actuarial regional disease control rate of 79%. All but five patients had confluent Grade 4 mucositis during treatment. Severe late complications attributable to radiation included mandibular necrosis, in-field osteosarcoma, and chronic dysphagia for solid foods. Conclusions: High rates of local and regional disease control were achieved with the concomitant boost fractionation schedule, with few cases of severe late
International Nuclear Information System (INIS)
Thode, L.E.
1981-01-01
A method is described for electron beam heating of a high-density plasma to drive a fast liner. An annular or solid relativistic electron beam is used to heat a plasma to kilovolt temperatures through streaming instabilities in the plasma. Energy deposited in the plasma then converges on a fast liner to explosively or ablatively drive the liner to implosion. (U.K.)
Fuzzy based finger vein recognition with rotation invariant feature matching
Ezhilmaran, D.; Joseph, Rose Bindu
2017-11-01
Finger vein recognition is a promising biometric with commercial applications which is explored widely in the recent years. In this paper, a finger vein recognition system is proposed using rotation invariant feature descriptors for matching after enhancing the finger vein images with an interval type-2 fuzzy method. SIFT features are extracted and matched using a matching score based on Euclidian distance. Rotation invariance of the proposed method is verified in the experiment and the results are compared with SURF matching and minutiae matching. It is seen that rotation invariance is verified and the poor quality issues are solved efficiently with the designed system of finger vein recognition during the analysis. The experiments underlines the robustness and reliability of the interval type-2 fuzzy enhancement and SIFT feature matching.
Measurement Invariance of Discipline in Different Cultural Contexts.
Huang, Li; Malone, Patrick S; Lansford, Jennifer E; Deater-Deckard, Kirby; Di Giunta, Laura; Bombi, Anna Silvia; Bornstein, Marc H; Chang, Lei; Dodge, Kenneth A; Oburu, Paul; Pastorelli, Concetta; Skinner, Ann T; Sorbring, Emma; Tapanya, Sombat; Tirado, Liliana Maria Uribe; Zelli, Arnaldo; Alampay, Liane; Al-Hassan, Suha M; Bacchini, Dario
2011-07-01
The measurement invariance of mother-reported use of 18 discipline strategies was examined in samples from 13 different ethnic/cultural groups in nine countries (China, Colombia, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States). Participants included approximately 100-120 mothers and their children aged 7 to 10 years from each group. The results of exploratory factor analyses and multigroup categorical confirmatory factor analyses (MCCFA) indicated that a seven-factor solution was feasible across the cultural groups, as shown by marginally sufficient evidence for configural and metric invariance for the mother-reported frequency on the discipline interview. This study makes a contribution on measurement invariance to the parenting literature, and establishes the mother-report aspect of the discipline interview as an instrument for use in further cross-cultural research on discipline.
ASIFT: An Algorithm for Fully Affine Invariant Comparison
Directory of Open Access Journals (Sweden)
Guoshen Yu
2011-02-01
Full Text Available If a physical object has a smooth or piecewise smooth boundary, its images obtained by cameras in varying positions undergo smooth apparent deformations. These deformations are locally well approximated by affine transforms of the image plane. In consequence the solid object recognition problem has often been led back to the computation of affine invariant image local features. The similarity invariance (invariance to translation, rotation, and zoom is dealt with rigorously by the SIFT method The method illustrated and demonstrated in this work, Affine-SIFT (ASIFT, simulates a set of sample views of the initial images, obtainable by varying the two camera axis orientation parameters, namely the latitude and the longitude angles, which are not treated by the SIFT method. Then it applies the SIFT method itself to all images thus generated. Thus, ASIFT covers effectively all six parameters of the affine transform.
Probability density functions for CP-violating rephasing invariants
Fortin, Jean-François; Giasson, Nicolas; Marleau, Luc
2018-05-01
The implications of the anarchy principle on CP violation in the lepton sector are investigated. A systematic method is introduced to compute the probability density functions for the CP-violating rephasing invariants of the PMNS matrix from the Haar measure relevant to the anarchy principle. Contrary to the CKM matrix which is hierarchical, it is shown that the Haar measure, and hence the anarchy principle, are very likely to lead to the observed PMNS matrix. Predictions on the CP-violating Dirac rephasing invariant |jD | and Majorana rephasing invariant |j1 | are also obtained. They correspond to 〈 |jD | 〉 Haar = π / 105 ≈ 0.030 and 〈 |j1 | 〉 Haar = 1 / (6 π) ≈ 0.053 respectively, in agreement with the experimental hint from T2K of |jDexp | ≈ 0.032 ± 0.005 (or ≈ 0.033 ± 0.003) for the normal (or inverted) hierarchy.
Isomorph invariance of the structure and dynamics of classical crystals
DEFF Research Database (Denmark)
Albrechtsen, Dan; Olsen, Andreas Elmerdahl; Pedersen, Ulf Rørbæk
2014-01-01
This paper shows by computer simulations that some crystalline systems have curves in their thermodynamic phase diagrams, so-called isomorphs, along which structure and dynamics in reduced units are invariant to a good approximation. The crystals are studied in a classical-mechanical framework......, which is generally a good description except significantly below melting. The existence of isomorphs for crystals is validated by simulations of particles interacting via the Lennard-Jones pair potential arranged into a face-centered cubic (fcc) crystalline structure; the slow vacancy-jump dynamics...... of a defective fcc crystal is also shown to be isomorph invariant. In contrast, a NaCl crystal model does not exhibit isomorph invariances. Other systems simulated, though in less detail, are the Wahnström binary Lennard-Jones crystal with the MgZn2 Laves crystal structure, monatomic fcc crystals of particles...
SPEEDY: An Eclipse-based IDE for invariant inference
Directory of Open Access Journals (Sweden)
David R. Cok
2014-04-01
Full Text Available SPEEDY is an Eclipse-based IDE for exploring techniques that assist users in generating correct specifications, particularly including invariant inference algorithms and tools. It integrates with several back-end tools that propose invariants and will incorporate published algorithms for inferring object and loop invariants. Though the architecture is language-neutral, current SPEEDY targets C programs. Building and using SPEEDY has confirmed earlier experience demonstrating the importance of showing and editing specifications in the IDEs that developers customarily use, automating as much of the production and checking of specifications as possible, and showing counterexample information directly in the source code editing environment. As in previous work, automation of specification checking is provided by back-end SMT solvers. However, reducing the effort demanded of software developers using formal methods also requires a GUI design that guides users in writing, reviewing, and correcting specifications and automates specification inference.
Open Gromov-Witten Invariants from the Augmentation Polynomial
Directory of Open Access Journals (Sweden)
Matthew Mahowald
2017-10-01
Full Text Available A conjecture of Aganagic and Vafa relates the open Gromov-Witten theory of X = O P 1 ( − 1 , − 1 to the augmentation polynomial of Legendrian contact homology. We describe how to use this conjecture to compute genus zero, one boundary component open Gromov-Witten invariants for Lagrangian submanifolds L K ⊂ X obtained from the conormal bundles of knots K ⊂ S 3 . This computation is then performed for two non-toric examples (the figure-eight and three-twist knots. For ( r , s torus knots, the open Gromov-Witten invariants can also be computed using Atiyah-Bott localization. Using this result for the unknot and the ( 3 , 2 torus knot, we show that the augmentation polynomial can be derived from these open Gromov-Witten invariants.
Boosted H->bb Tagger In Run II
Sahinsoy, Merve; The ATLAS collaboration
2016-01-01
Several searches for Higgs bosons decaying to bquark pairs benefit from the increased Run II centreofmass energy by exploiting the large transversmomentum (boosted) Higgs boson regime, where the two bjets are merged into one largeradius jet. ATLAS uses a boosted H>bb tagger algorithm to separate the Higgs signal from the background processes (QCD, W and Z bosons, top quarks). The tagger takes as input a largeR=1.0 jet calibrating the pseudorapidity, energy and mass scale. The tagger employs btagging, Higgs candidate mass, and substructure information. The performance of several operating points in Higgs boson signal and QCD and ttbar allhadronic backgrounds are presented. Systematic uncertainties are evaluated so that this tagger can be used in analyses.
High Efficient Universal Buck Boost Solar Array Regulator SAR Module
Kimmelmann, Stefan; Knorr, Wolfgang
2014-08-01
The high efficient universal Buck Boost Solar Array Regulator (SAR) module concept is applicable for a wide range of input and output voltages. The single point failure tolerant SAR module contains 3 power converters for the transfer of the SAR power to the battery dominated power bus. The converters are operating parallel in a 2 out of 3 redundancy and are driven by two different controllers. The output power of one module can be adjusted up to 1KW depending on the requirements. The maximum power point tracker (MPPT) is placed on a separate small printed circuit board and can be used if no external tracker signal is delivered. Depending on the mode and load conditions an efficiency of more than 97% is achievable. The stable control performance is achieved by implementing the magnetic current sense detection. The sensed power coil current is used in Buck and Boost control mode.
Investigating light NMSSM pseudoscalar states with boosted ditau tagging
Energy Technology Data Exchange (ETDEWEB)
Conte, Eric [Groupe de Recherche de Physique des Hautes Énergies (GRPHE),Université de Haute-Alsace, IUT Colmar,34 rue du Grillenbreit BP 50568, 68008 Colmar Cedex (France); Fuks, Benjamin [Sorbonne Universités, UPMC University Paris 06,UMR 7589, LPTHE, F-75005, Paris (France); CNRS, UMR 7589, LPTHE, F-75005, Paris (France); Guo, Jun [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190 (China); Institut Pluridisciplinaire Hubert Curien/Département Recherches Subatomiques,Université de Strasbourg/CNRS-IN2P3,23 rue du Loess, F-67037 Strasbourg (France); Li, Jinmian; Williams, Anthony G. [ARC Centre of Excellence for Particle Physics at the Terascale and CSSM,Department of Physics, University of Adelaide,Adelaide, SA 5005 (Australia)
2016-05-17
We study a class of realizations of the Next-to-Minimal Supersymmetric Standard Model that is motivated by dark matter and Higgs data, and in which the lightest pseudoscalar Higgs boson mass is smaller than twice the bottom quark mass and greater than twice the tau lepton mass. In such scenarios, the lightest pseudoscalar Higgs boson can be copiously produced at the LHC from the decay of heavier superpartners and will dominantly further decay into a pair of tau leptons that is generally boosted. We make use of a boosted object tagging technique designed to tag such a ditau jet, and estimate the sensitivity of the LHC to the considered supersymmetric scenarios with 20 to 50 fb{sup −1} of proton-proton collisions at a center-of-mass energy of 13 TeV.
Diode-Assisted Buck-Boost Voltage-Source Inverters
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus
2009-01-01
, a number of diode-assisted inverter variants can be designed with each having its own operational principle and voltage gain expression. For controlling them, a generic modulation scheme that can be used for controlling all diode-assisted variants with minimized harmonic distortion and component stress......This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques....... Using the diode-assisted network, the proposed inverters can naturally configure themselves to perform capacitive charging in parallel and discharging in series to give a higher voltage multiplication factor without compromising waveform quality. In addition, by adopting different front-end circuitries...
High Temperature Boost (HTB) Power Processing Unit (PPU) Formulation Study
Chen, Yuan; Bradley, Arthur T.; Iannello, Christopher J.; Carr, Gregory A.; Mohammad, Mojarradi M.; Hunter, Don J.; DelCastillo, Linda; Stell, Christopher B.
2013-01-01
This technical memorandum is to summarize the Formulation Study conducted during fiscal year 2012 on the High Temperature Boost (HTB) Power Processing Unit (PPU). The effort is authorized and supported by the Game Changing Technology Division, NASA Office of the Chief Technologist. NASA center participation during the formulation includes LaRC, KSC and JPL. The Formulation Study continues into fiscal year 2013. The formulation study has focused on the power processing unit. The team has proposed a modular, power scalable, and new technology enabled High Temperature Boost (HTB) PPU, which has 5-10X improvement in PPU specific power/mass and over 30% in-space solar electric system mass saving.
Boosting bonsai trees for handwritten/printed text discrimination
Ricquebourg, Yann; Raymond, Christian; Poirriez, Baptiste; Lemaitre, Aurélie; Coüasnon, Bertrand
2013-12-01
Boosting over decision-stumps proved its efficiency in Natural Language Processing essentially with symbolic features, and its good properties (fast, few and not critical parameters, not sensitive to over-fitting) could be of great interest in the numeric world of pixel images. In this article we investigated the use of boosting over small decision trees, in image classification processing, for the discrimination of handwritten/printed text. Then, we conducted experiments to compare it to usual SVM-based classification revealing convincing results with very close performance, but with faster predictions and behaving far less as a black-box. Those promising results tend to make use of this classifier in more complex recognition tasks like multiclass problems.
Machine learning strategies for systems with invariance properties
Ling, Julia; Jones, Reese; Templeton, Jeremy
2016-08-01
In many scientific fields, empirical models are employed to facilitate computational simulations of engineering systems. For example, in fluid mechanics, empirical Reynolds stress closures enable computationally-efficient Reynolds Averaged Navier Stokes simulations. Likewise, in solid mechanics, constitutive relations between the stress and strain in a material are required in deformation analysis. Traditional methods for developing and tuning empirical models usually combine physical intuition with simple regression techniques on limited data sets. The rise of high performance computing has led to a growing availability of high fidelity simulation data. These data open up the possibility of using machine learning algorithms, such as random forests or neural networks, to develop more accurate and general empirical models. A key question when using data-driven algorithms to develop these empirical models is how domain knowledge should be incorporated into the machine learning process. This paper will specifically address physical systems that possess symmetry or invariance properties. Two different methods for teaching a machine learning model an invariance property are compared. In the first method, a basis of invariant inputs is constructed, and the machine learning model is trained upon this basis, thereby embedding the invariance into the model. In the second method, the algorithm is trained on multiple transformations of the raw input data until the model learns invariance to that transformation. Results are discussed for two case studies: one in turbulence modeling and one in crystal elasticity. It is shown that in both cases embedding the invariance property into the input features yields higher performance at significantly reduced computational training costs.
Synaptotagmin 7 confers frequency invariance onto specialized depressing synapses
Turecek, Josef; Jackman, Skyler L.; Regehr, Wade G.
2017-11-01
At most synapses in the brain, short-term plasticity dynamically modulates synaptic strength. Rapid frequency-dependent changes in synaptic strength have key roles in sensory adaptation, gain control and many other neural computations. However, some auditory, vestibular and cerebellar synapses maintain constant strength over a wide range of firing frequencies, and as a result efficiently encode firing rates. Despite its apparent simplicity, frequency-invariant transmission is difficult to achieve because of inherent synaptic nonlinearities. Here we study frequency-invariant transmission at synapses from Purkinje cells to deep cerebellar nuclei and at vestibular synapses in mice. Prolonged activation of these synapses leads to initial depression, which is followed by steady-state responses that are frequency invariant for their physiological activity range. We find that synaptotagmin 7 (Syt7), a calcium sensor for short-term facilitation, is present at both synapses. It was unclear why a sensor for facilitation would be present at these and other depressing synapses. We find that at Purkinje cell and vestibular synapses, Syt7 supports facilitation that is normally masked by depression, which can be revealed in wild-type mice but is absent in Syt7 knockout mice. In wild-type mice, facilitation increases with firing frequency and counteracts depression to produce frequency-invariant transmission. In Syt7-knockout mice, Purkinje cell and vestibular synapses exhibit conventional use-dependent depression, weakening to a greater extent as the firing frequency is increased. Presynaptic rescue of Syt7 expression restores both facilitation and frequency-invariant transmission. Our results identify a function for Syt7 at synapses that exhibit overall depression, and demonstrate that facilitation has an unexpected and important function in producing frequency-invariant transmission.
Boosted PWM open loop control of hydraulic proportional valves
International Nuclear Information System (INIS)
Amirante, R.; Innone, A.; Catalano, L.A.
2008-01-01
This paper presents an innovative open loop control technique for direct single stage hydraulic proportional valves whose response rate is significantly higher than that obtained by standard open loop control techniques, even comparable to more costly commercial closed loop systems. Different from standard open loop techniques, which provide the coil with a constant current proportional to the target position, the control strategy proposed in this paper employs the peak and hold (P and H) technique, widely used in Diesel engine modern supply systems, to boost the duty cycle value of the pulse width modulation (PWM) signal for a short time, namely during the spool displacement, while maintaining a lower duty cycle for holding the spool in the required opening position. The developed 'boosted PWM' technique only requires a low cost microcontroller, such as a peripheral interface controller (PIC) equipped with a metal oxide semiconductor (MOS) power driver. The PWM parameters are calibrated as a function of the spool displacement so as to maximize the response rate without introducing overshoots: the collected data are stored in the PIC. Different valve opening procedures with step response have been compared to demonstrate the merits of the proposed boosted PWM technique. No overshoots have been registered. Moreover, the proposed method is characterized by a significantly higher response rate with respect to a standard open loop control, which approximately has the same cost. Similar experimental tests show that the proposed boosted PWM technique has a response rate even higher than that provided by the more costly commercial closed loop system mounted on the valve, and it produces no overshoots
Corrector del factor de potencia mediante convertidor boost multifase
Barriocanal Escobar, Jordi
2009-01-01
Las fuentes de alimentación tradicionales provocan una clara disminución del factor de potencia. Es necesario encontrar un circuito que pase la corr iente alterna a corriente continua, con un elevado factor de potencia. Para ello se puede utilizar un convertidor de poten cia Boost posterior a un rectificador. Se aumenta el factor de potencia pero en la tensión de salida aparece un rizado de baja frecuenci...
Motivating quantum field theory: the boosted particle in a box
International Nuclear Information System (INIS)
Vutha, Amar C
2013-01-01
It is a maxim often stated, yet rarely illustrated, that the combination of special relativity and quantum mechanics necessarily leads to quantum field theory. An elementary illustration is provided using the familiar particle in a box, boosted to relativistic speeds. It is shown that quantum fluctuations of momentum lead to energy fluctuations, which are inexplicable without a framework that endows the vacuum with dynamical degrees of freedom and allows particle creation/annihilation. (letters and comments)
The Voltage Boost Enabled by Luminescence Extraction in Solar Cells
Energy Technology Data Exchange (ETDEWEB)
Ganapati, Vidya; Steiner, Myles A.; Yablonovitch, Eli
2016-11-21
A new physical principle has emerged to produce record voltages and efficiencies in photovoltaic cells, 'luminescence extraction.' This is exemplified by the mantra 'a good solar cell should also be a good LED.' Luminescence extraction is the escape of internal photons out of the front surface of a solar cell. Basic thermodynamics says that the voltage boost should be related to concentration ratio, C, of a resource by ..delta..V=(kT/q)ln{C}. In light trapping, (i.e. when the solar cell is textured and has a perfect back mirror) the concentration ratio of photons C={4n2}, so one would expect a voltage boost of ..delta..V=kT ln{4n2} over a solar cell with no texture and zero back reflectivity, where n is the refractive index. Nevertheless, there has been ambiguity over the voltage benefit to be expected from perfect luminescence extraction. Do we gain an open circuit voltage boost of ..delta..V=(kT/q)ln{n2}, ..delta..V=(kT/q)ln{2n2}, or ..delta..V=(kT/q)ln{4n2}? What is responsible for this voltage ambiguity ..delta..V=(kT/q)ln{4}=36mVolts? We show that different results come about, depending on whether the photovoltaic cell is optically thin or thick to its internal luminescence. In realistic intermediate cases of optical thickness the voltage boost falls in between; ln{n2}q..delta..V/kT)<;ln{4n2}.
Concurrent Boost with Adjuvant Breast Hypofractionated Radiotherapy and Toxicity Assessment
Directory of Open Access Journals (Sweden)
Mona M. Sayed
2015-01-01
Full Text Available Background: The use of shorter radiotherapy schedules has an economic and logistic advantage for radiotherapy departments, as well as a high degree of patient convenience. The aim of this study is to assess the acute and short-term late toxicities of a hypofractionated radiotherapy schedule with a concomitant boost. Methods: We enrolled 57 eligible patients as group A. These patients received 42.5 Gy in 16 fractions of 2.66 Gy each to the whole breast over 3.2 weeks. A concomitant electron boost of 12 Gy in 16 fractions was also administered which gave an additional 0.75 Gy daily to the lumpectomy area for a total radiation dose of 54.5 Gy. Toxicity was recorded at three weeks and at three months for this group as well as for a control group (group B. The control group comprised 76 eligible patients treated conventionally with 50 Gy to the whole breast over five weeks followed by a sequential electron boost of 12 Gy in 2 Gy per fraction. Results: There were no statistically significant differences observed in the incidence of acute skin toxicity, breast pain, and edema recorded at three weeks or pigmentation and fibrosis recorded at three months between the two groups (P0.05. Conclusion: The results of this study suggest there are no increased acute and shortterm late toxicities affiliated with the hypofractionated schedule plus a concomitant boost as prescribed compared to the conventional fractionation of adjuvant breast radiotherapy. Large randomized trials and long-term follow-up are needed to confirm these favorable findings.
Spectral invariants of operators of Dirac type on partitioned manifolds
DEFF Research Database (Denmark)
Booss-Bavnbek, Bernhelm; Bleecker, D.
2004-01-01
We review the concepts of the index of a Fredholm operator, the spectral flow of a curve of self-adjoint Fredholm operators, the Maslov index of a curve of Lagrangian subspaces in symplectic Hilbert space, and the eta invariant of operators of Dirac type on closed manifolds and manifolds...... with boundary. We emphasize various (occasionally overlooked) aspects of rigorous definitions and explain the quite different stability properties. Moreover, we utilize the heat equation approach in various settings and show how these topological and spectral invariants are mutually related in the study...
Weyl versus conformal invariance in quantum field theory
Farnsworth, Kara; Luty, Markus A.; Prilepina, Valentina
2017-10-01
We argue that conformal invariance in flat spacetime implies Weyl invariance in a general curved background metric for all unitary theories in spacetime dimensions d ≤ 10. We also study possible curvature corrections to the Weyl transformations of operators, and show that these are absent for operators of sufficiently low dimensionality and spin. We find possible `anomalous' Weyl transformations proportional to the Weyl (Cotton) tensor for d > 3 ( d = 3). The arguments are based on algebraic consistency conditions similar to the Wess-Zumino consistency conditions that classify possible local anomalies. The arguments can be straightforwardly extended to larger operator dimensions and higher d with additional algebraic complexity.
Trace Maps, Invariants, and Some of Their Applications
Baake, M.; Grimm, U.; Joseph, D.
Trace maps of two-letter substitution rules are investigated with special emphasis on the underlying algebraic structure and on the existence of invariants. We illustrate the results with the generalized Fibonacci chains and show that the well-known Fricke character I(x, y, z)=x2+y2+z2-2xyz-1 is not the only type of invariant that can occur. We discuss several physical applications to electronic spectra including the gap-labeling theorem, to kicked two-level systems, and to the classical 1D Ising model with non-commuting transfer matrices.
Gauge invariant treatment of the electroweak phase transition
International Nuclear Information System (INIS)
Buchmueller, W.; Fodor, Z.; Hebecker, A.
1994-03-01
We evaluate the gauge invariant effective potential for the composite field σ = 2Φ † Φin the SU(2)-Higgs model at finite temperature. Symmetric and broken phases correspond to the domains σ ≤ T 2 /3 and σ > T 2 /3, respectively. The effective potential increases very steeply at small values of σ. Predictions for several observables, derived from the ordinary and the gauge invariant effective potential, are compared. Good agreement is found for the critical temperature and the jump in the order parameter. The results for the latent heat differ significantly for large Higgs masses. (orig.)
Bidirectional log-polar mapping for invariant object recognition
Mehanian, Courosh; Rak, Steven J.
1991-08-01
The representation of visual information in human striate cortex is of significance to machine vision. Invariance to certain geometrical transformations in the field-of-view may be provided by the computational anatomy of the visual cortex. For example, there is evidence that the retino-cortical mapping is closely approximated by a log-polar transform. When combined with the foveation response, log-polar mapping can provide a basis for translation, rotation, and scale-invariant perception. There is also evidence that the visual system is sensitive to the spatial frequency content of its input. Although a Fourier transform is physiologically implausible, some authors have suggested its use for invariant object recognition because the magnitude of the Fourier transform is shift invariant. The Fourier transform magnitude operation followed by log-polar mapping can also provide a basis for translation, rotation, and scale-invariant perception. Both of these image-transform (feature mapping) algorithms give mathematical invariance to translation, rotation, and dilation. For an automatic recognition system, however, the feature mapping module has to be robust to discretization error, noise, and possible obscuration. Robustness considerations led to the development of the bi- directional log-polar mapping (BPM) algorithm. The BPM algorithm overcomes the pixel- dropout problems associated with conventional approaches to log-polar mapping. The authors evaluate several feature mapping models, both biologically and mathematically inspired, for their effect on recognition performance when embedded in a neural-network-based, object- recognition system. The modular recognition system, consisting of image restoration, detection, segmentation, feature extraction, invariant mapping, and classification, is being developed to classify objects in laser radar range imagery. Synthetic laser radar range images of four vehicles rotated in the field-of-view, scaled to various ranges, and
Object detection based on improved color and scale invariant features
Chen, Mengyang; Men, Aidong; Fan, Peng; Yang, Bo
2009-10-01
A novel object detection method which combines color and scale invariant features is presented in this paper. The detection system mainly adopts the widely used framework of SIFT (Scale Invariant Feature Transform), which consists of both a keypoint detector and descriptor. Although SIFT has some impressive advantages, it is not only computationally expensive, but also vulnerable to color images. To overcome these drawbacks, we employ the local color kernel histograms and Haar Wavelet Responses to enhance the descriptor's distinctiveness and computational efficiency. Extensive experimental evaluations show that the method has better robustness and lower computation costs.
Seven Experiments to Test the Local Lorentz Invariance of c
Gezari, Daniel Y.
2005-01-01
The speed of light has never been measured directly with a moving detector to test the fundamental assertion of special relativity that c is invariant to motion of the observer. Seven simple experiments are proposed, four of which could test the invariance of c to motion of the detector. Three other observations of moving sources could test Einstein s second postulate and the relativity of stellar aberration. There are lingering concerns that the speed of light may depend on the motion of the observer, after all. This issue can now be resolved by experiment.
Translation invariant time-dependent massive gravity: Hamiltonian analysis
Energy Technology Data Exchange (ETDEWEB)
Mourad, Jihad; Steer, Danièle A. [Laboratoire APC -- Astroparticule et Cosmologie, Université Paris Diderot, 75013 Paris (France); Noui, Karim, E-mail: mourad@apc.univ-paris7.fr, E-mail: karim.noui@lmpt.univ-tours.fr, E-mail: steer@apc.univ-paris7.fr [Laboratoire de Mathématiques et Physique Théorique, Université François Rabelais, Parc de Grandmont, 37200 Tours (France)
2014-09-01
The canonical structure of the massive gravity in the first order moving frame formalism is studied. We work in the simplified context of translation invariant fields, with mass terms given by general non-derivative interactions, invariant under the diagonal Lorentz group, depending on the moving frame as well as a fixed reference frame. We prove that the only mass terms which give 5 propagating degrees of freedom are the dRGT mass terms, namely those which are linear in the lapse. We also complete the Hamiltonian analysis with the dynamical evolution of the system.
Breakdown of invariant attractors for the dissipative standard map.
Calleja, Renato; Celletti, Alessandra
2010-03-01
We implement different methods for the computation of the breakdown threshold of invariant attractors in the dissipative standard mapping. A first approach is based on the computation of the Sobolev norms of the function parametrizing the solution. Then we look for the approximating periodic orbits and we analyze their stability in order to compute the critical threshold at which an invariant attractor breaks down. We also determine the domain of convergence of the dissipative standard mapping by extending the computations to the complex parameter space as well as by investigating a two-frequency model.
Scaling theory of [Formula: see text] topological invariants.
Chen, Wei; Sigrist, Manfred; Schnyder, Andreas P
2016-09-14
For inversion-symmetric topological insulators and superconductors characterized by [Formula: see text] topological invariants, two scaling schemes are proposed to judge topological phase transitions driven by an energy parameter. The scaling schemes renormalize either the phase gradient or the second derivative of the Pfaffian of the time-reversal operator, through which the renormalization group flow of the driving energy parameter can be obtained. The Pfaffian near the time-reversal invariant momentum is revealed to display a universal critical behavior for a great variety of models examined.
Projection Operators and Moment Invariants to Image Blurring
Czech Academy of Sciences Publication Activity Database
Flusser, Jan; Suk, Tomáš; Boldyš, Jiří; Zitová, Barbara
2015-01-01
Roč. 37, č. 4 (2015), s. 786-802 ISSN 0162-8828 R&D Projects: GA ČR GA13-29225S; GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : Blurred image * N-fold rotation symmetry * projection operators * image moments * moment invariants * blur invariants * object recognition Subject RIV: JD - Computer Applications, Robotics Impact factor: 6.077, year: 2015 http://library.utia.cas.cz/separaty/2014/ZOI/flusser-0434521.pdf
Smooth invariant densities for random switching on the torus
Bakhtin, Yuri; Hurth, Tobias; Lawley, Sean D.; Mattingly, Jonathan C.
2018-04-01
We consider a random dynamical system obtained by switching between the flows generated by two smooth vector fields on the 2d-torus, with the random switchings happening according to a Poisson process. Assuming that the driving vector fields are transversal to each other at all points of the torus and that each of them allows for a smooth invariant density and no periodic orbits, we prove that the switched system also has a smooth invariant density, for every switching rate. Our approach is based on an integration by parts formula inspired by techniques from Malliavin calculus.
Asia-Pacific Region Water Boosted Rocket Events
Oyama, K.-I.; Hidayat, A.; Sofyan, E.; Sinha, H. S. S.; Herudi, K.; Kubota, T.; Sukkarieh, S.; Arban, J. L.; Chung, D. M.; Medagangoda, I.; Mohd, Z. B.; Pitan, S.; Chin, C.; Sarkar, F. R.
2010-05-01
Space Education and Awareness Working Group, which is one of four working groups of Asia-Pacific Regional Space Agency Forum, had organized water boosted rocket competition in Japan in 2005, in Indonesia in 2006, and in 2007 in India. One junior high school student (12-15 years old) and one leader from 9 and 13 Asian/Pacific countries attended the 1st, 2nd, and 3rd water rocket events, respectively. The 4th event is planned in Vietnam, in December 2008. The manuscript introduces the structure and activities of Space Education and Awareness Working Group, which is working under Asia-Pacific Regional Space Agency Forum sponsored by Ministry of Education, Culture, Sports, and Technology of Japan; and application of water-boosted rocket to other field is described. Details of the water boosted rocket events, such as the purpose, competition rules, and the schedules are provided. Finally we discuss the issues to be taken into account for the future event.
Stereotactic Body Radiation Therapy Boost in Locally Advanced Pancreatic Cancer
International Nuclear Information System (INIS)
Seo, Young Seok; Kim, Mi-Sook; Yoo, Sung Yul; Cho, Chul Koo; Yang, Kwang Mo; Yoo, Hyung Jun; Choi, Chul Won; Lee, Dong Han; Kim, Jin; Kim, Min Suk; Kang, Hye Jin; Kim, YoungHan
2009-01-01
Purpose: To investigate the clinical application of a stereotactic body radiation therapy (SBRT) boost in locally advanced pancreatic cancer patients with a focus on local efficacy and toxicity. Methods and Materials: We retrospectively reviewed 30 patients with locally advanced and nonmetastatic pancreatic cancer who had been treated between 2004 and 2006. Follow-up duration ranged from 4 to 41 months (median, 14.5 months). A total dose of 40 Gy was delivered in 20 fractions using a conventional three-field technique, and then a single fraction of 14, 15, 16, or 17 Gy SBRT was administered as a boost without a break. Twenty-one patients received chemotherapy. Overall and local progression-free survival were calculated and prognostic factors were evaluated. Results: One-year overall survival and local progression-free survival rates were 60.0% and 70.2%, respectively. One patient (3%) developed Grade 4 toxicity. Carbohydrate antigen 19-9 response was found to be an independent prognostic factor for survival. Conclusions: Our findings indicate that a SBRT boost provides a safe means of increasing radiation dose. Based on the results of this study, we recommend that a well controlled Phase II study be conducted on locally advanced pancreatic cancer.
Boosted dark matter signals uplifted with self-interaction
Energy Technology Data Exchange (ETDEWEB)
Kong, Kyoungchul, E-mail: kckong@ku.edu [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Mohlabeng, Gopolang, E-mail: mohlabeng319@gmail.com [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Park, Jong-Chul, E-mail: log1079@gmail.com [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)
2015-04-09
We explore detection prospects of a non-standard dark sector in the context of boosted dark matter. We focus on a scenario with two dark matter particles of a large mass difference, where the heavier candidate is secluded and interacts with the standard model particles only at loops, escaping existing direct and indirect detection bounds. Yet its pair annihilation in the galactic center or in the Sun may produce boosted stable particles, which could be detected as visible Cherenkov light in large volume neutrino detectors. In such models with multiple candidates, self-interaction of dark matter particles is naturally utilized in the assisted freeze-out mechanism and is corroborated by various cosmological studies such as N-body simulations of structure formation, observations of dwarf galaxies, and the small scale problem. We show that self-interaction of the secluded (heavier) dark matter greatly enhances the capture rate in the Sun and results in promising signals at current and future experiments. We perform a detailed analysis of the boosted dark matter events for Super-Kamiokande, Hyper-Kamiokande and PINGU, including notable effects such as evaporation due to self-interaction and energy loss in the Sun.
Chagas Parasite Detection in Blood Images Using AdaBoost
Directory of Open Access Journals (Sweden)
Víctor Uc-Cetina
2015-01-01
Full Text Available The Chagas disease is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi. Visual detection of such parasite through microscopic inspection is a tedious and time-consuming task. In this paper, we provide an AdaBoost learning solution to the task of Chagas parasite detection in blood images. We give details of the algorithm and our experimental setup. With this method, we get 100% and 93.25% of sensitivity and specificity, respectively. A ROC comparison with the method most commonly used for the detection of malaria parasites based on support vector machines (SVM is also provided. Our experimental work shows mainly two things: (1 Chagas parasites can be detected automatically using machine learning methods with high accuracy and (2 AdaBoost + SVM provides better overall detection performance than AdaBoost or SVMs alone. Such results are the best ones known so far for the problem of automatic detection of Chagas parasites through the use of machine learning, computer vision, and image processing methods.
Boosted dark matter signals uplifted with self-interaction
Directory of Open Access Journals (Sweden)
Kyoungchul Kong
2015-04-01
Full Text Available We explore detection prospects of a non-standard dark sector in the context of boosted dark matter. We focus on a scenario with two dark matter particles of a large mass difference, where the heavier candidate is secluded and interacts with the standard model particles only at loops, escaping existing direct and indirect detection bounds. Yet its pair annihilation in the galactic center or in the Sun may produce boosted stable particles, which could be detected as visible Cherenkov light in large volume neutrino detectors. In such models with multiple candidates, self-interaction of dark matter particles is naturally utilized in the assisted freeze-out mechanism and is corroborated by various cosmological studies such as N-body simulations of structure formation, observations of dwarf galaxies, and the small scale problem. We show that self-interaction of the secluded (heavier dark matter greatly enhances the capture rate in the Sun and results in promising signals at current and future experiments. We perform a detailed analysis of the boosted dark matter events for Super-Kamiokande, Hyper-Kamiokande and PINGU, including notable effects such as evaporation due to self-interaction and energy loss in the Sun.
Boosting target tracking using particle filter with flow control
Moshtagh, Nima; Chan, Moses W.
2013-05-01
Target detection and tracking with passive infrared (IR) sensors can be challenging due to significant degradation and corruption of target signature by atmospheric transmission and clutter effects. This paper summarizes our efforts in phenomenology modeling of boosting targets with IR sensors, and developing algorithms for tracking targets in the presence of background clutter. On the phenomenology modeling side, the clutter images are generated using a high fidelity end-to-end simulation testbed. It models atmospheric transmission, structured clutter and solar reflections to create realistic background images. The dynamics and intensity of a boosting target are modeled and injected onto the background scene. Pixel level images are then generated with respect to the sensor characteristics. On the tracking analysis side, a particle filter for tracking targets in a sequence of clutter images is developed. The particle filter is augmented with a mechanism to control particle flow. Specifically, velocity feedback is used to constrain and control the particles. The performance of the developed "adaptive" particle filter is verified with tracking of a boosting target in the presence of clutter and occlusion.
Darvas, Gyrgy
2009-01-01
The paper discusses the mathematical consequences of the application of derived variables in gauge fields. Physics is aware of several phenomena, which depend first of all on velocities (like e.g., the force caused by charges moving in a magnetic field, or the Lorentz transformation). Applying the property of the second Noether theorem, that allowed generalised variables, this paper extends the article by Al-Kuwari and Taha (1991) with a new conclusion. They concluded that there are no extra conserved currents associated with local gauge invariance. We show, that in a more general case, there are further conserved Noether currents. In its method the paper reconstructs the clue introduced by Utiyama (1956, 1959) and followed by Al-Kuwari and Taha (1991) in the presence of a gauge field that depends on the co-ordinates of the velocity space. In this course we apply certain (but not full) analogies with Mills (1989). We show, that handling the space-time coordinates as implicit variables in the gauge field, reproduces the same results that have been derived in the configuration space (i.e., we do not lose information), while the proposed new treatment gives additional information extending those. The result is an extra conserved Noether current.
Kaplan, S A; ter Haar, D
2013-01-01
Plasma Astrophysics is a translation from the Russian language; the topics discussed are based on lectures given by V.N. Tsytovich at several universities. The book describes the physics of the various phenomena and their mathematical formulation connected with plasma astrophysics. This book also explains the theory of the interaction of fast particles plasma, their radiation activities, as well as the plasma behavior when exposed to a very strong magnetic field. The text describes the nature of collective plasma processes and of plasma turbulence. One author explains the method of elementary
Swanson, DG
1989-01-01
Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th
Perturbation of frame sequences in shift-invariant spaces
DEFF Research Database (Denmark)
Christensen, Ole; Kim, Hong Oh; Kim, Rae Young
2005-01-01
We prove a new perturbation criteria for frame sequences, which generalizes previous results and is easier to apply. In the special case of frames infinitely generated shift-invariant subspaces of L2(ℝd) the condition can be formulated in terms of the norm of a finite Gram matrix and a correspond...
Three-dimensional low-energy topological invariants
International Nuclear Information System (INIS)
Bakalarska, M.; Broda, B.
2000-01-01
A description of the one-loop approximation formula for the partition function of a three-dimensional abelian version of the Donaldson-Witten theory is proposed. The one-loop expression is shown to contain such topological invariants of a three-dimensional manifold M like the Reidemeister-Ray-Singer torsion τ R and Betti numbers. (orig.)
Conserved currents and gauge invariance in Yang-Mills theory
International Nuclear Information System (INIS)
Barnich, G.; Brandt, F.; Henneaux, M.
1994-01-01
It is shown that in the absence of free abelian gauge fields, the conserved currents of (classical) Yang-Mills gauge models coupled to matter fields can be always redefined so as to be gauge invariant. This is a direct consequence of the general analysis of the Wess-Zumino consistency condition for Yang-Mills theory that we have provided recently. (orig.)
Gauge invariance and equations of motion for closed string modes
Directory of Open Access Journals (Sweden)
B. Sathiapalan
2014-12-01
Full Text Available We continue earlier discussions on loop variables and the exact renormalization group on the string world sheet for closed and open string backgrounds. The world sheet action with a UV regulator is written in a generally background covariant way by introducing a background metric. It is shown that the renormalization group gives background covariant equations of motion – this is the gauge invariance of the graviton. Interaction is written in terms of gauge invariant and generally covariant field strength tensors. The basic idea is to work in Riemann normal coordinates and covariantize the final equation. It turns out that the equations for massive modes are gauge invariant only if the space–time curvature of the (arbitrary background is zero. The exact RG equations give quadratic equations of motion for all the modes including the physical graviton. The level (2,2¯ massive field equations are used to illustrate the techniques. At this level there are mixed symmetry tensors. Gauge invariant interacting equations can be written down. In flat space an action can also be written for the free theory.
Rotation-invariant fingerprint matching using radon and DCT
Indian Academy of Sciences (India)
A new set of promising rotation-invariant features based on radon and discrete cosine transform (DCT) is proposed for fingerprint matching. The radon and DCT of a tiny area in the region of core point of fingerprint image is computed. In the proposed method only 34% DCT coefficients are used for feature extraction.
An invariant symmetric non-selfadjoint differential operator
Thomas, Erik G.F.
2002-01-01
Let D be a symmetric left invariant differential operator on a unimodular Lie group G of type I. Then we show that D is essentially self-adjoint if and only if for almost all pi is an element of (G) over cap, with respect to the Plancherel measure, the operator pi(D) is essentially self-adjoint.
Transformations and invariants for dihedral Gauss hypergeometric functions
Vidunas, Raimundas
2011-01-01
Hypergeometric equations with a dihedral monodromy group can be solved in terms of elementary functions. This paper gives explicit general expressions for quadratic monodromy invariants for these hypergeometric equations, using a generalization of Clausen's formula and terminating double hypergeometric sums. Besides, pull-back transformations for the dihedral hypergeometric equations are presented, including Klein's pullback transformations for the equations with a finite (dihedral) monodromy...
Second invariant for two-dimensional classical super systems
Indian Academy of Sciences (India)
In §3, we obtain a set of coupled linear equations using graded bracket relation for the canonical conjugate variable where the existence of the second-order invariant for the super dynamical system under consideration is being as- sumed. A consistent solution of these equations yields the systems which are integrable.