WorldWideScience

Sample records for discrete lie advection

  1. Authalic parameterization of general surfaces using Lie advection.

    Science.gov (United States)

    Zou, Guangyu; Hu, Jiaxi; Gu, Xianfeng; Hua, Jing

    2011-12-01

    Parameterization of complex surfaces constitutes a major means of visualizing highly convoluted geometric structures as well as other properties associated with the surface. It also enables users with the ability to navigate, orient, and focus on regions of interest within a global view and overcome the occlusions to inner concavities. In this paper, we propose a novel area-preserving surface parameterization method which is rigorous in theory, moderate in computation, yet easily extendable to surfaces of non-disc and closed-boundary topologies. Starting from the distortion induced by an initial parameterization, an area restoring diffeomorphic flow is constructed as a Lie advection of differential 2-forms along the manifold, which yields equality of the area elements between the domain and the original surface at its final state. Existence and uniqueness of result are assured through an analytical derivation. Based upon a triangulated surface representation, we also present an efficient algorithm in line with discrete differential modeling. As an exemplar application, the utilization of this method for the effective visualization of brain cortical imaging modalities is presented. Compared with conformal methods, our method can reveal more subtle surface patterns in a quantitative manner. It, therefore, provides a competitive alternative to the existing parameterization techniques for better surface-based analysis in various scenarios.

  2. Lie symmetries and conserved quantities of discrete nonholonomic Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    Wang Xing-Zhong; Fu Hao; Fu Jing-Li

    2012-01-01

    This paper focuses on studying Lie symmetries and conserved quantities of discrete nonholonomic Hamiltonian systems.Firstly,the discrete generalized Hamiltonian canonical equations and discrete energy equation of nonholonomic Hamiltonian systems are derived from discrete Hamiltonian action.Secondly,the determining equations and structure equation of Lie symmetry of the system are obtained.Thirdly,the Lie theorems and the conservation quantities are given for the discrete nonholonomic Hamiltonian systems.Finally,an example is discussed to illustrate the application of the results.

  3. Local and nonlocal advected invariants and helicities in magnetohydrodynamics and gas dynamics I: Lie dragging approach

    Science.gov (United States)

    Webb, G. M.; Dasgupta, B.; McKenzie, J. F.; Hu, Q.; Zank, G. P.

    2014-03-01

    In this paper advected invariants and conservation laws in ideal magnetohydrodynamics (MHD) and gas dynamics are obtained using Lie dragging techniques. There are different classes of invariants that are advected or Lie dragged with the flow. Simple examples are the advection of the entropy S (a 0-form), and the conservation of magnetic flux (an invariant 2-form advected with the flow). The magnetic flux conservation law is equivalent to Faraday's equation. The gauge condition for the magnetic helicity to be advected with the flow is determined. Different variants of the helicity in ideal fluid dynamics and MHD including: fluid helicity, cross helicity and magnetic helicity are investigated. The fluid helicity conservation law and the cross-helicity conservation law in MHD are derived for the case of a barotropic gas. If the magnetic field lies in the constant entropy surface, then the gas pressure can depend on both the entropy and the density. In these cases the conservation laws are local conservation laws. For non-barotropic gases, we obtain nonlocal conservation laws for fluid helicity and cross helicity by using Clebsch variables. These nonlocal conservation laws are the main new results of the paper. Ertel's theorem and potential vorticity, the Hollman invariant, and the Godbillon-Vey invariant for special flows for which the magnetic helicity is zero are also discussed.

  4. Local and Nonlocal Advected Invariants and Helicities in Magnetohydrodynamics and Gas Dynamics I: Lie Dragging Approach

    CERN Document Server

    Webb, Gary M; McKenzie, James F; Hu, Qiang; Zank, Gary P

    2013-01-01

    In this paper we discuss conservation laws in ideal magnetohydrodynamics (MHD) and gas dynamics associated with advected invariants. The invariants in some cases, can be related to fluid relabelling symmetries associated with the Lagrangian map. There are different classes of invariants that are advected or Lie dragged with the flow. Simple examples are the advection of the entropy S (a 0-form), and the conservation of magnetic flux (an invariant 2-form advected with the flow). The magnetic flux conservation law is equivalent to Faraday's equation. We discuss the gauge condition required for the magnetic helicity to be advected with the flow. The conditions for the cross helicity to be an invariant are discussed. We discuss the different variants of helicity in fluid dynamics and in MHD, including: fluid helicity, cross helicity and magnetic helicity. The fluid helicity conservation law and the cross helcity conservation law in MHD are derived for the case of a barotropic gas. If the magnetic field lies in th...

  5. Geometric Approach to Lie Symmetry of Discrete Time Toda Equation

    Institute of Scientific and Technical Information of China (English)

    JIA Xiao-Yu; WANG Na

    2009-01-01

    By using the extended Harrison and Estabrook geometric approach,we investigate the Lie symmetry of discrete time Toda equation from the geometric point of view.Its one-dimensional continuous symmetry group is presented.

  6. On Approximation of Lie Groups by Discrete Subgroups

    Indian Academy of Sciences (India)

    Hatem Hamrouni; Salah Souissi

    2014-02-01

    A locally compact group is said to be approximated by discrete sub-groups (in the sense of Tôyama) if there is a sequence of discrete subgroups of that converges to in the Chabauty topology (or equivalently, in the Vietoris topology). The notion of approximation of Lie groups by discrete subgroups was introduced by Tôyama in Kodai Math. Sem. Rep. 1 (1949) 36–37 and investigated in detail by Kuranishi in Nagoya Math. J. 2 (1951) 63–71. It is known as a theorem of Tôyama that any connected Lie group approximated by discrete subgroups is nilpotent. The converse, in general, does not hold. For example, a connected simply connected nilpotent Lie group is approximated by discrete subgroups if and only if has a rational structure. On the other hand, if is a discrete uniform subgroup of a connected, simply connected nilpotent Lie group then is approximated by discrete subgroups $_n$ containing . The proof of the above result is by induction on the dimension of , and gives an algorithm for inductively determining $_n$. The purpose of this paper is to give another proof in which we present an explicit formula for the sequence $(_n)_{n≥ 0}$ in terms of . Several applications are given.

  7. Noether symmetry and Lie symmetry of discrete holonomic systems with dependent coordinates

    Institute of Scientific and Technical Information of China (English)

    Shi Shen-Yang; Huang Xiao-Hong

    2008-01-01

    The Noether symmetry,the Lie symmetry and the conserved quantity of discrete holonomic systems with dependent coordinates are investigated in this paper.The Noether symmetry provides a discrete Noether identity and a conserved qu中antity of the system.The invariance of discrete motion equations under infinitesimal transformation groups is defined as the Lie symmetry,and the condition of obtaining the Noether conserved quantity from the Lie symmetry is also presented.An example is discussed to show the applications of the results.

  8. Lie Symmetry Analysis of the Inhomogeneous Toda Lattice Equation via Semi-Discrete Exterior Calculus

    Science.gov (United States)

    Liu, Jiang; Wang, Deng-Shan; Yin, Yan-Bin

    2017-06-01

    In this work, the Lie point symmetries of the inhomogeneous Toda lattice equation are obtained by semi-discrete exterior calculus, which is a semi-discrete version of Harrison and Estabrook’s geometric approach. A four-dimensional Lie algebra and its one-, two- and three-dimensional subalgebras are given. Two similarity reductions of the inhomogeneous Toda lattice equation are obtained by using the symmetry vectors. Supported by National Natural Science Foundation of China under Grant Nos. 11375030, 11472315, and Department of Science and Technology of Henan Province under Grant No. 162300410223 and Beijing Finance Funds of Natural Science Program for Excellent Talents under Grant No. 2014000026833ZK19

  9. Discrete Cocompact Subgroups of the Five-Dimensional Connected and Simply Connected Nilpotent Lie Groups

    Directory of Open Access Journals (Sweden)

    Amira Ghorbel

    2009-02-01

    Full Text Available The discrete cocompact subgroups of the five-dimensional connected, simply connected nilpotent Lie groups are determined up to isomorphism. Moreover, we prove if G = N × A is a connected, simply connected, nilpotent Lie group with an Abelian factor A, then every uniform subgroup of G is the direct product of a uniform subgroup of N and Z^r where r = dim A.

  10. Upper Triangular Matrix of Lie Algebra and a New Discrete Integrable Coupling System

    Institute of Scientific and Technical Information of China (English)

    YU Fa-Jun; ZHANG Hong-Qing

    2007-01-01

    The upper triangular matrix of Lie algebra is used to construct integrable couplings of discrete solition equations.Correspondingly,a feasible way to construct integrable couplings is presented.A nonlinear lattice soliton equation spectral problem is obtained and leads to a novel hierarchy of the nonlinear lattice equation hierarchy.It indicates that the study of integrable couplings using upper triangular matrix of Lie algebra is an important step towards constructing integrable systems.

  11. The TUBES algorithm for the exact representation of advective transport in a two-dimensional discretized flow field

    Energy Technology Data Exchange (ETDEWEB)

    Costa-Cabral, M.C. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik

    1999-07-01

    Current Lagrangian models for simulating advective transport of trace species in a discretized two-dimensional flow field use simplified descriptions of tracer sources, receptors and flow paths. When 'forward trajectories' are used, a diffuse source spread over a two-dimensional grid cell is treated as a single point source located at the cell's center, and its flow is projected in the downflow direction by a line. When 'backward trajectories' are used, each cell is treated as a point receptor and flow is projected back in time in the upflow direction by a line. In both cases, two-dimensional sources or receptors are treated as zero dimensional, and two-dimensional flow tubes are replaced by one-dimensional lines. While these simplifications may be acceptable in some cases, they can generate large errors when the flow field contains regions of considerable divergence of flow directions, or when fine scales are used. A new algorithm is introduced, called TUBES, which provides an exact solution to advective transport in a discretized two-dimensional flow field. TUBES uses two-dimensional flow tubes whose width expands and contracts over directionally divergent and convergent regions of the flow field, respectively. TUBES has applications in a wide variety of the earth sciences, including atmospheric science, oceanography, and surface and groundwater hydrology. (orig.) [German] Gegenwaertige Lagrange-Modelle zur Simulation advektiver Transporte von Tracern in einem diskretisierten zweidimensionalen Stroemungsfeld verwenden vereinfachte Beschreibungen der Quellen, Rezeptoren und Transportwege. Bei der Verwendung vorwaerts gerichteter Trajektorien ('forward trajectories') werden diffusive Quellen, die ueber eine zweidimensionale Gitterzelle verteilt sind, als Punktquelle behandelt, und der Transport mit der Stroemung erfolgt entlang einer Linie. Bei der Verwendung rueckwaerts gerichteter Trajektorien ('backward trajectories

  12. Three semi-direct sum Lie algebras and three discrete integrable couplings associated with the modified KdV lattice equation.

    Science.gov (United States)

    Yu, Zhang; Zhang, Yufeng

    2009-01-30

    Three semi-direct sum Lie algebras are constructed, which is an efficient and new way to obtain discrete integrable couplings. As its applications, three discrete integrable couplings associated with the modified KdV lattice equation are worked out. The approach can be used to produce other discrete integrable couplings of the discrete hierarchies of solition equations.

  13. Lie algebras

    CERN Document Server

    Jacobson, Nathan

    1979-01-01

    Lie group theory, developed by M. Sophus Lie in the 19th century, ranks among the more important developments in modern mathematics. Lie algebras comprise a significant part of Lie group theory and are being actively studied today. This book, by Professor Nathan Jacobson of Yale, is the definitive treatment of the subject and can be used as a textbook for graduate courses.Chapter I introduces basic concepts that are necessary for an understanding of structure theory, while the following three chapters present the theory itself: solvable and nilpotent Lie algebras, Carlan's criterion and its

  14. Lie Superalgebras

    CERN Document Server

    Papi, Paolo; Advances in Lie Superalgebras

    2014-01-01

    The volume is the outcome of the conference "Lie superalgebras," which was held at the Istituto Nazionale di Alta Matematica, in 2012. The conference gathered many specialists in the subject, and the talks held provided comprehensive insights into the newest trends in research on Lie superalgebras (and related topics like vertex algebras, representation theory and supergeometry). The book contains contributions of many leading esperts in the field and provides a complete account of the newest trends in research on Lie Superalgebras.

  15. Frontiers of chaotic advection

    CERN Document Server

    Aref, Hassan; Budišić, Marko; Cartwright, Julyan H E; Clercx, Herman J H; Feudel, Ulrike; Golestanian, Ramin; Gouillart, Emmanuelle; Guer, Yves Le; van Heijst, GertJan F; Krasnopolskaya, Tatyana S; MacKay, Robert S; Meleshko, Vyacheslav V; Metcalfe, Guy; Mezić, Igor; de Moura, Alessandro P S; Omari, Kamal El; Piro, Oreste; Speetjens, Michel F M; Sturman, Rob; Thiffeault, Jean-Luc; Tuval, Idan

    2014-01-01

    We review the present position of and survey future perspectives in the physics of chaotic advection; the field that emerged three decades ago at the intersection of fluid mechanics and nonlinear dynamics, which encompasses a range of applications with length scales ranging from micrometers to hundreds of kilometers, including systems as diverse as mixing and thermal processing of viscous fluids, micro-fluidics, biological flows, and large-scale dispersion of pollutants in oceanographic and atmospheric flows.

  16. Magnetic-dipole-to-electric-quadrupole cross-susceptibilities for relativistic hydrogenlike atoms in some low-lying discrete energy eigenstates

    CERN Document Server

    Stefańska, Patrycja

    2016-01-01

    In this paper we present tabulated data for magnetic-dipole-to-electric-quadrupole cross-susceptibilities ($\\chi_{\\textrm{M}1 \\to \\textrm{E}2}$) for Dirac one-electron atoms with a pointlike, spinless and motionless nucleus of charge $Ze$. Numerical values of this susceptibility for the hydrogen atom ($Z=1$) and for hydrogenic ions with $2 \\leqslant Z \\leqslant 137$ are computed from the general analytical formula, recently derived by us [P. Stefa{\\'n}ska, Phys. Rev. A 93 (2016) 022504], valid for an arbitrary discrete energy eigenstate. In this work we provide 30 tables with the values of $\\chi_{\\textrm{M}1 \\to \\textrm{E}2}$ for the ground state, and also for the first, the second and the third set of excited states (i.e.: 2s$_{1/2}$, 2p$_{1/2}$, 2p$_{3/2}$, 3s$_{1/2}$, 3p$_{1/2}$, 3p$_{3/2}$, 3d$_{3/2}$, 3d$_{5/2}$, 4s$_{1/2}$, 4p$_{1/2}$, 4p$_{3/2}$, 4d$_{3/2}$, 4d$_{5/2}$, 4f$_{5/2}$ and 4f$_{7/2}$) of the relativistic hydrogenlike atoms. The value of the inverse of the fine-structure constant used in the...

  17. New complex variable meshless method for advection-diffusion problems

    Institute of Scientific and Technical Information of China (English)

    Wang Jian-Fei; Cheng Yu-Min

    2013-01-01

    In this paper,an improved complex variable meshless method (ICVMM) for two-dimensional advection-diffusion problems is developed based on improved complex variable moving least-square (ICVMLS) approximation.The equivalent functional of two-dimensional advection-diffusion problems is formed,the variation method is used to obtain the equation system,and the penalty method is employed to impose the essential boundary conditions.The difference method for two-point boundary value problems is used to obtain the discrete equations.Then the corresponding formulas of the ICVMM for advection-diffusion problems are presented.Two numerical examples with different node distributions are used to validate and investigate the accuracy and efficiency of the new method in this paper.It is shown that ICVMM is very effective for advection-diffusion problems,and has a good convergent character,accuracy,and computational efficiency.

  18. LAYER DEPENDENT ADVECTION IN CMAQ

    Science.gov (United States)

    The advection methods used in CMAQ require that the Courant-Friedrichs-Lewy (CFL) condition be satisfied for numerical stability and accuracy. In CMAQ prior to version 4.3, the ADVSTEP algorithm established CFL-safe synchronization and advection timesteps that were uniform throu...

  19. Groupoids, Discrete Mechanics, and Discrete Variation

    Institute of Scientific and Technical Information of China (English)

    GUO Jia-Feng; JIA Xiao-Yu; WU Ke; ZHAO Wei-Zhong

    2008-01-01

    After introducing some of the basic definitions and results from the theory of groupoid and Lie algebroid,we investigate the discrete Lagrangian mechanics from the viewpoint of groupoid theory and give the connection between groupoids variation and the methods of the first and second discrete variational principles.

  20. Fast multigrid solution of the advection problem with closed characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Yavneh, I. [Israel Inst. of Technology, Haifa (Israel); Venner, C.H. [Univ. of Twente, Enschede (Netherlands); Brandt, A. [Weizmann Inst. of Science, Rehovot (Israel)

    1996-12-31

    The numerical solution of the advection-diffusion problem in the inviscid limit with closed characteristics is studied as a prelude to an efficient high Reynolds-number flow solver. It is demonstrated by a heuristic analysis and numerical calculations that using upstream discretization with downstream relaxation-ordering and appropriate residual weighting in a simple multigrid V cycle produces an efficient solution process. We also derive upstream finite-difference approximations to the advection operator, whose truncation terms approximate {open_quotes}physical{close_quotes} (Laplacian) viscosity, thus avoiding spurious solutions to the homogeneous problem when the artificial diffusivity dominates the physical viscosity.

  1. Lie groups and Lie algebras for physicists

    CERN Document Server

    Das, Ashok

    2015-01-01

    The book is intended for graduate students of theoretical physics (with a background in quantum mechanics) as well as researchers interested in applications of Lie group theory and Lie algebras in physics. The emphasis is on the inter-relations of representation theories of Lie groups and the corresponding Lie algebras.

  2. A generalized advection dispersion equation

    Indian Academy of Sciences (India)

    Abdon Atangana

    2014-02-01

    This paper examines a possible effect of uncertainties, variability or heterogeneity of any dynamic system when being included in its evolution rule; the notion is illustrated with the advection dispersion equation, which describes the groundwater pollution model. An uncertain derivative is defined; some properties of the operator are presented. The operator is used to generalize the advection dispersion equation. The generalized equation differs from the standard equation in four properties. The generalized equation is solved via the variational iteration technique. Some illustrative figures are presented.

  3. Weak Lie symmetry and extended Lie algebra

    Energy Technology Data Exchange (ETDEWEB)

    Goenner, Hubert [Institute for Theoretical Physics, Friedrich-Hund-Platz 1, University of Goettingen, D-37077 Gottingen (Germany)

    2013-04-15

    The concept of weak Lie motion (weak Lie symmetry) is introduced. Applications given exhibit a reduction of the usual symmetry, e.g., in the case of the rotation group. In this context, a particular generalization of Lie algebras is found ('extended Lie algebras') which turns out to be an involutive distribution or a simple example for a tangent Lie algebroid. Riemannian and Lorentz metrics can be introduced on such an algebroid through an extended Cartan-Killing form. Transformation groups from non-relativistic mechanics and quantum mechanics lead to such tangent Lie algebroids and to Lorentz geometries constructed on them (1-dimensional gravitational fields).

  4. 3-LIE BIALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    白瑞蒲; 程宇; 李佳倩; 孟伟

    2014-01-01

    3-Lie algebras have close relationships with many important fields in mathemat-ics and mathematical physics. This article concerns 3-Lie algebras. The concepts of 3-Lie coalgebras and 3-Lie bialgebras are given. The structures of such categories of algebras and the relationships with 3-Lie algebras are studied. And the classification of 4-dimensional 3-Lie coalgebras and 3-dimensional 3-Lie bialgebras over an algebraically closed field of char-acteristic zero are provided.

  5. Consistency Problem with Tracer Advection in the Atmospheric Model GAMIL

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai; WAN Hui; WANG Bin; ZHANG Meigen

    2008-01-01

    The radon transport test,which is a widely used test case for atmospheric transport models,is carried out to evaluate the tracer advection schemes in the Grid-Point Atmospheric Model of IAP-LASG (GAMIL).TWO of the three available schemes in the model are found to be associated with significant biases in the polar regions and in the upper part of the atmosphere,which implies potentially large errors in the simulation of ozone-like tracers.Theoretical analyses show that inconsistency exists between the advection schemes and the discrete continuity equation in the dynamical core of GAMIL and consequently leads to spurious sources and sinks in the tracer transport equation.The impact of this type of inconsistency is demonstrated by idealized tests and identified as the cause of the aforementioned biases.Other potential effects of this inconsistency are also discussed.Results of this study provide some hints for choosing suitable advection schemes in the GAMIL model.At least for the polar-region-concentrated atmospheric components and the closely correlated chemical species,the Flux-Form Semi-Lagrangian advection scheme produces more reasonable simulations of the large-scale transport processes without significantly increasing the computational expense.

  6. Smoothed particle hydrodynamics model for Landau-Lifshitz-Navier-Stokes and advection-diffusion equations.

    Science.gov (United States)

    Kordilla, Jannes; Pan, Wenxiao; Tartakovsky, Alexandre

    2014-12-14

    We propose a novel smoothed particle hydrodynamics (SPH) discretization of the fully coupled Landau-Lifshitz-Navier-Stokes (LLNS) and stochastic advection-diffusion equations. The accuracy of the SPH solution of the LLNS equations is demonstrated by comparing the scaling of velocity variance and the self-diffusion coefficient with kinetic temperature and particle mass obtained from the SPH simulations and analytical solutions. The spatial covariance of pressure and velocity fluctuations is found to be in a good agreement with theoretical models. To validate the accuracy of the SPH method for coupled LLNS and advection-diffusion equations, we simulate the interface between two miscible fluids. We study formation of the so-called "giant fluctuations" of the front between light and heavy fluids with and without gravity, where the light fluid lies on the top of the heavy fluid. We find that the power spectra of the simulated concentration field are in good agreement with the experiments and analytical solutions. In the absence of gravity, the power spectra decay as the power -4 of the wavenumber-except for small wavenumbers that diverge from this power law behavior due to the effect of finite domain size. Gravity suppresses the fluctuations, resulting in much weaker dependence of the power spectra on the wavenumber. Finally, the model is used to study the effect of thermal fluctuation on the Rayleigh-Taylor instability, an unstable dynamics of the front between a heavy fluid overlaying a light fluid. The front dynamics is shown to agree well with the analytical solutions.

  7. Solvable quadratic Lie algebras

    Institute of Scientific and Technical Information of China (English)

    ZHU; Linsheng

    2006-01-01

    A Lie algebra endowed with a nondegenerate, symmetric, invariant bilinear form is called a quadratic Lie algebra. In this paper, the author investigates the structure of solvable quadratic Lie algebras, in particular, the solvable quadratic Lie algebras whose Cartan subalgebras consist of semi-simple elements, the author presents a procedure to construct a class of quadratic Lie algebras from the point of view of cohomology and shows that all solvable quadratic Lie algebras can be obtained in this way.

  8. Stochastic Lie group integrators

    CERN Document Server

    Malham, Simon J A

    2007-01-01

    We present Lie group integrators for nonlinear stochastic differential equations with non-commutative vector fields whose solution evolves on a smooth finite dimensional manifold. Given a Lie group action that generates transport along the manifold, we pull back the stochastic flow on the manifold to the Lie group via the action, and subsequently pull back the flow to the corresponding Lie algebra via the exponential map. We construct an approximation to the stochastic flow in the Lie algebra via closed operations and then push back to the Lie group and then to the manifold, thus ensuring our approximation lies in the manifold. We call such schemes stochastic Munthe-Kaas methods after their deterministic counterparts. We also present stochastic Lie group integration schemes based on Castell--Gaines methods. These involve using an underlying ordinary differential integrator to approximate the flow generated by a truncated stochastic exponential Lie series. They become stochastic Lie group integrator schemes if...

  9. Advective Coalescence in Chaotic Flows

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, Takashi; Toroczkai, Zoltan; Grebogi, Celso

    2001-07-16

    We investigate the reaction kinetics of small spherical particles with inertia, obeying coalescence type of reaction, B+B{yields}B , and being advected by hydrodynamical flows with time-periodic forcing. In contrast to passive tracers, the particle dynamics is governed by the strongly nonlinear Maxey-Riley equations, which typically create chaos in the spatial component of the particle dynamics, appearing as filamental structures in the distribution of the reactants. Defining a stochastic description supported on the natural measure of the attractor, we show that, in the limit of slow reaction, the reaction kinetics assumes a universal behavior exhibiting a t{sup -1} decay in the amount of reagents, which become distributed on a subset of dimension D{sub 2} , where D{sub 2} is the correlation dimension of the chaotic flow.

  10. Correcting temporal sampling error in radar-rainfall: Effect of advection parameters and rain storm characteristics on the correction accuracy

    Science.gov (United States)

    Seo, Bong-Chul; Krajewski, Witold F.

    2015-12-01

    This study offers a method to correct for the radar temporal sampling error when determining radar-rainfall accumulations. The authors evaluate the correction effect with respect to multiple factors associated with storm advection, rainfall characteristics, and different rainfall accumulation time scales. The advection method presented in this study uses linear interpolation of static rain storm locations observed at two intermittent radar sampling times to correct for the missed rainfall accumulations. The advection correction is applied to the high space (0.5 km) and time (5-min) resolution radar-rainfall products provided by the Iowa Flood Center. We use the ground reference data from a high quality and high density rain gauge network distributed over the Turkey River basin in Iowa to evaluate the advection corrected rain fields. We base our evaluation on six rain events and examine the correction performance/improvement with respect to the advection discretization, spatial grid aggregation, rainfall basin coverage, and conditional average rainfall intensity. The results show that the 1-min advection discretization is sufficient to represent the observed distribution of storm velocities for the presented cases. Grid aggregation that is motivated by the need to expedite the computation may induce errors in estimating advection vectors. The authors found that while the advection correction tends to enhance the QPE accuracy for intense rain storms over small or isolated areas, it has little impact on the improvement of light rain estimation.

  11. Lying with Maps

    OpenAIRE

    Monmonier, Mark

    2005-01-01

    Darrell Huff’s How to Lie with Statistics was the inspiration for How to Lie with Maps, in which the author showed that geometric distortion and graphic generalization of data are unavoidable elements of cartographic representation. New examples of how ill-conceived or deliberately contrived statistical maps can greatly distort geographic reality demonstrate that lying with maps is a special case of lying with statistics. Issues addressed include the effects of map scale on geometry and featu...

  12. Discrete dynamics versus analytic dynamics

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2014-01-01

    For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...

  13. Parenting by Lying

    Science.gov (United States)

    Heyman, Gail D.; Luu, Diem H.; Lee, Kang

    2009-01-01

    The present set of studies identifies the phenomenon of "parenting by lying", in which parents lie to their children as a means of influencing their emotional states and behaviour. In Study 1, undergraduates (n = 127) reported that their parents had lied to them while maintaining a concurrent emphasis on the importance of honesty. In Study 2 (n =…

  14. Additive Lie ($\\xi$-Lie) Derivations and Generalized Lie ($\\xi$-Lie) Derivations on Prime Algebras

    CERN Document Server

    Qi, Xiaofei

    2010-01-01

    The additive (generalized) $\\xi$-Lie derivations on prime algebras are characterized. It is shown, under some suitable assumption, that an additive map $L$ is an additive (generalized) Lie derivation if and only if it is the sum of an additive (generalized) derivation and an additive map from the algebra into its center vanishing all commutators; is an additive (generalized) $\\xi$-Lie derivation with $\\xi\

  15. Turbulent dynamo with advective magnetic helicity flux

    CERN Document Server

    Del Sordo, Fabio; Brandenburg, Axel

    2012-01-01

    Many astrophysical bodies harbor magnetic fields that are thought to be sustained by dynamo processes. However, it has been argued that the production of large-scale magnetic fields by a mean-field dynamo is strongly suppressed at large magnetic Reynolds numbers owing to the conservation of magnetic helicity. This phenomenon is known as catastrophic quenching. Advection of magnetic field toward the outer boundaries and away from the dynamo is expected to alleviate such quenching. Examples are stellar and galactic winds. Such advection might be able to overcome the constraint imposed by the conservation of magnetic helicity, transporting a fraction of it outside the domain in which the dynamo operates. We study how the dynamo process is affected by advection. In particular, we study the relative roles played by advective and diffusive fluxes of magnetic helicity. We do this by performing direct numerical simulations of a turbulent dynamo of alpha^2 type driven by forced turbulence in a Cartesian domain in the ...

  16. The ease of lying

    NARCIS (Netherlands)

    Verschuere, B.; Spruyt, A.; Meijer, E.H.; Otgaar, H.

    2011-01-01

    Brain imaging studies suggest that truth telling constitutes the default of the human brain and that lying involves intentional suppression of the predominant truth response. By manipulating the truth proportion in the Sheffield lie test, we investigated whether the dominance of the truth response i

  17. The ease of lying

    NARCIS (Netherlands)

    Verschuere, B.; Spruyt, A.; Meijer, E.H.; Otgaar, H.

    2011-01-01

    Brain imaging studies suggest that truth telling constitutes the default of the human brain and that lying involves intentional suppression of the predominant truth response. By manipulating the truth proportion in the Sheffield lie test, we investigated whether the dominance of the truth response

  18. Whoppers and White Lies.

    Science.gov (United States)

    Vermillion, Marti

    1985-01-01

    Lying is a symptom of a much broader problem. Primary motivations are need for acceptance, fear of punishment, and desire for attention. Children learn about honesty through observation, both directly and indirectly. Admitting mistakes, especially to children, is invaluable and can help break the lying syndrome. (MT)

  19. Medicine, lies and deceptions.

    Science.gov (United States)

    Benn, P

    2001-04-01

    This article offers a qualified defence of the view that there is a moral difference between telling lies to one's patients, and deceiving them without lying. However, I take issue with certain arguments offered by Jennifer Jackson in support of the same conclusion. In particular, I challenge her claim that to deny that there is such a moral difference makes sense only within a utilitarian framework, and I cast doubt on the aptness of some of her examples of non-lying deception. But I argue that lies have a greater tendency to damage trust than does non-lying deception, and suggest that since many doctors do believe there is a moral boundary between the two types of deception, encouraging them to violate that boundary may have adverse general effects on their moral sensibilities.

  20. Construction of Lie algebras and invariant tensors through abelian semigroups

    Energy Technology Data Exchange (ETDEWEB)

    Izaurieta, Fernando; RodrIguez, Eduardo; Salgado, Patricio [Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)], E-mail: fizaurie@gmail.com, E-mail: edurodriguez@udec.cl, E-mail: pasalgad@udec.cl

    2008-11-01

    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.

  1. Evasive Lying in Strategic Communication

    OpenAIRE

    Khalmetski, Kiryl; Rockenbach, Bettina; Werner, Peter

    2017-01-01

    In a sender-receiver game we investigate if sanctions for lying induce more truth-telling. Senders may not only choose between truth-telling and (explicit) lying, but may also engage in evasive lying by credibly pretending not to know. Sanctions promote truth-telling if senders cannot engage in evasive lying. If evasive lying is possible, explicit lying is largely substituted by evasive lying, in line with the notion that evasive lying is perceived as sufficiently less psychologically costly.

  2. On lying and deceiving.

    Science.gov (United States)

    Bakhurst, D

    1992-06-01

    This article challenges Jennifer Jackson's recent defence of doctors' rights to deceive patients. Jackson maintains there is a general moral difference between lying and intentional deception: while doctors have a prima facie duty not to lie, there is no such obligation to avoid deception. This paper argues 1) that an examination of cases shows that lying and deception are often morally equivalent, and 2) that Jackson's position is premised on a species of moral functionalism that misconstrues the nature of moral obligation. Against Jackson, it is argued that both lying and intentional deception are wrong where they infringe a patient's right to autonomy or his/her right to be treated with dignity. These rights represent 'deontological constraints' on action, defining what we must not do whatever the functional value of the consequences. Medical ethics must recognise such constraints if it is to contribute to the moral integrity of medical practice.

  3. Lie algebras and applications

    CERN Document Server

    Iachello, Francesco

    2015-01-01

    This course-based primer provides an introduction to Lie algebras and some of their applications to the spectroscopy of molecules, atoms, nuclei and hadrons. In the first part, it concisely presents the basic concepts of Lie algebras, their representations and their invariants. The second part includes a description of how Lie algebras are used in practice in the treatment of bosonic and fermionic systems. Physical applications considered include rotations and vibrations of molecules (vibron model), collective modes in nuclei (interacting boson model), the atomic shell model, the nuclear shell model, and the quark model of hadrons. One of the key concepts in the application of Lie algebraic methods in physics, that of spectrum generating algebras and their associated dynamic symmetries, is also discussed. The book highlights a number of examples that help to illustrate the abstract algebraic definitions and includes a summary of many formulas of practical interest, such as the eigenvalues of Casimir operators...

  4. Additive Lie (ζ-Lie) Derivations and Generalized Lie (ζ-Lie)Derivations on Prime Algebras

    Institute of Scientific and Technical Information of China (English)

    Xiao Fei QI; Jin Chuan HOU

    2013-01-01

    The additive (generalized) ζ-Lie derivations on prime algebras are characterized.It is shown,under some suitable assumptions,that an additive map L is an additive generalized Lie derivation if and only if it is the sum of an additive generalized derivation and an additive map from the algebra into its center vanishing all commutators; is an additive (generalized) ζ-Lie derivation with ζ ≠ 1 if and only if it is an additive (generalized) derivation satisfying L(ζA) =ζL(A) for all A.These results are then used to characterize additive (generalized) ζ-Lie derivations on several operator algebras such as Banach space standard operator algebras and von Neumman algebras.

  5. Lying, honor, and contradiction

    National Research Council Canada - National Science Library

    Michael Gilsenan

    2016-01-01

    .... +Superscript 1 -Superscript With a particular concentration on the manifold practices of what will be called "lying," I shall try to show the way in which individuals in a Lebanese village negotiate...

  6. Discrete Mathematics

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    The objectives of Discrete Mathematics (IDISM2) are: The introduction of the mathematics needed for analysis, design and verification of discrete systems, including the application within programming languages for computer systems. Having passed the IDISM2 course, the student will be able...... to accomplish the following: -Understand and apply formal representations in discrete mathematics. -Understand and apply formal representations in problems within discrete mathematics. -Understand methods for solving problems in discrete mathematics. -Apply methods for solving problems in discrete mathematics......; construct a finite state machine for a given application. Apply these concepts to new problems. The teaching in Discrete Mathematics is a combination of sessions with lectures and students solving problems, either manually or by using Matlab. Furthermore a selection of projects must be solved and handed...

  7. Variational Integration for Ideal MHD with Built-in Advection Equations

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yao [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Qin, Hong [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Burby, J. W. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Bhattacharjee, A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2014-08-05

    Newcomb's Lagrangian for ideal MHD in Lagrangian labeling is discretized using discrete exterior calculus. Variational integrators for ideal MHD are derived thereafter. Besides being symplectic and momentum preserving, the schemes inherit built-in advection equations from Newcomb's formulation, and therefore avoid solving them and the accompanying error and dissipation. We implement the method in 2D and show that numerical reconnection does not take place when singular current sheets are present. We then apply it to studying the dynamics of the ideal coalescence instability with multiple islands. The relaxed equilibrium state with embedded current sheets is obtained numerically.

  8. Lying in neuropsychology.

    Science.gov (United States)

    Seron, X

    2014-10-01

    The issue of lying occurs in neuropsychology especially when examinations are conducted in a forensic context. When a subject intentionally either presents non-existent deficits or exaggerates their severity to obtain financial or material compensation, this behaviour is termed malingering. Malingering is discussed in the general framework of lying in psychology, and the different procedures used by neuropsychologists to evidence a lack of collaboration at examination are briefly presented and discussed. When a lack of collaboration is observed, specific emphasis is placed on the difficulty in unambiguously establishing that this results from the patient's voluntary decision.

  9. Optically-thick accretion discs with advection

    Institute of Scientific and Technical Information of China (English)

    陈林红; 吴枚; 尚仁成

    2002-01-01

    The structures of optically-thick accretion discs with radial advection have been investigated by the iteration and integration algorithms. The advective cooling term changes mostly the inner part of disc solution, and even results in an optically-thick advection-dominated accretion flow (ADAF). Three distinct branches-the outer Shakura-Sunyaev disc (SSD), the inner ADAF and the middle transition layer-are found for a super-Eddington disc. The SSD-ADAF transition radius can be estimated as 18(M/ME)RG where RG is the Schwarzschild radius, M is the mass accretion rate and ME is the Eddington accretion rate. SSD solutions calculated with the iteration and integration methods are identical, while ADAF solutions obtained by these two methods differ greatly. Detailed algorithms and their differences have been analysed. The iteration algorithm is not self-consistent, since it implies that the dimensionless advection factor ξ is invariant, but in the inner ADAF region the variation of ξ is not negligible. The integration algorithm is always effective for the whole region of an optically-thick disc if the accretion rate is no smaller than 10-4ME. For optically-thin discs, the validity of these two algorithms is different. We suggest that the integration method be employed to calculate the global solution of a disc model without assuming ξ to be a constant. We also discuss its application to the emergent continuum spectrum in order to explain observational facts.

  10. Ensemble simulations with discrete classical dynamics

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2013-01-01

    For discrete classical Molecular dynamics (MD) obtained by the "Verlet" algorithm (VA) with the time increment $h$ there exist a shadow Hamiltonian $\\tilde{H}$ with energy $\\tilde{E}(h)$, for which the discrete particle positions lie on the analytic trajectories for $\\tilde{H}$. $\\tilde...

  11. Discrete integrable system and its integrable coupling

    Institute of Scientific and Technical Information of China (English)

    LI Zhu

    2009-01-01

    This paper derives new discrete integrable system based on discrete isospectral problem. It shows that the hierarchy is completely integrable in the Liouville sense and possesses bi-Hamiltonian structure. Finally, integrable couplings of the obtained system is given by means of semi-direct sums of Lie algebras.

  12. On the Logic of Lying

    NARCIS (Netherlands)

    H. van Ditmarsch (Hans); D.J.N. van Eijck (Jan); F.A.G. Sietsma (Floor); Y. Wang (Yanjing); D.J.N. van Eijck (Jan); R. Verbrugge

    2011-01-01

    htmlabstractWe look at lying as an act of communication, where (i) the proposition that is communicated is not true, (ii) the utterer of the lie knows (or believes) that what she communicates is not true, and (iii) the utterer of the lie intends the lie to be taken as truth. Rather than dwell on

  13. Discrete Breathers

    CERN Document Server

    Flach, S

    1998-01-01

    Nonlinear classical Hamiltonian lattices exhibit generic solutions in the form of discrete breathers. These solutions are time-periodic and (typically exponentially) localized in space. The lattices exhibit discrete translational symmetry. Discrete breathers are not confined to certain lattice dimensions. Necessary ingredients for their occurence are the existence of upper bounds on the phonon spectrum (of small fluctuations around the groundstate) of the system as well as the nonlinearity in the differential equations. We will present existence proofs, formulate necessary existence conditions, and discuss structural stability of discrete breathers. The following results will be also discussed: the creation of breathers through tangent bifurcation of band edge plane waves; dynamical stability; details of the spatial decay; numerical methods of obtaining breathers; interaction of breathers with phonons and electrons; movability; influence of the lattice dimension on discrete breather properties; quantum lattic...

  14. Application of Lie groups to discretizing nuclear engineering problems

    Science.gov (United States)

    Grove, Travis Justin

    A method utilizing groups of point transformations is applied to the three and four group time-independent neutron diffusion equations to obtain invariant difference equations for one-region and composite-region domains in one-dimensional Cartesian, cylindrical, and spherical geometries. Also, the theory behind this particular method will be discussed. A comparison of the invariant difference equations will be made to standard finite difference equations as well as to analytical results. From the analytical results, it will be shown that the invariant difference technique gives exact analytical solutions for the grid point values. The construction of invariant difference operators technique is also applied to the one-dimensional P 3 equations from neutron transport theory in Cartesian geometry, using the FLIP formulation, which allows PL equations to be written in the form of sets of coupled ordinary differential equations. The use of finite transforms will be examined to transform multi-dimensional problems into one-dimension where then the construction of invariant difference operators technique can be used to create difference equations. The solutions to the set of equations can then be transformed back into the multi-dimensional geometries. The use of finite transforms along with the construction of invariant difference operators technique is applied to a simple two-dimensional benchmark problem. In addition, a method using groups of point transformations along with Noether's theorem is shown to generate a conservation law that can be used to create a two-term recurrence relation which calculates numerically exact Green's functions in one dimension for the time-independent neutron diffusion equation for Cartesian, cylindrical, and spherical geometries. This method will be expanded to constructing two-term recurrence relations for an arbitrary number of spatial regions, as well as detailing starting point values for type 2 and type 3 homogeneous endpoint boundary conditions. Finally, the method of constructing two-term recurrence relations will be applied to Green's function matrices for the one-dimensional time-independent neutron diffusion equation for Cartesian, cylindrical, and spherical geometries. In particular, two-term recurrence relations for the off-diagonal elements of the Green's function matrices will be derived, and the method is adapted to take into account discontinuities in the value of a function.

  15. Lie algebraic noncommutative gravity

    Science.gov (United States)

    Banerjee, Rabin; Mukherjee, Pradip; Samanta, Saurav

    2007-06-01

    We exploit the Seiberg-Witten map technique to formulate the theory of gravity defined on a Lie algebraic noncommutative space-time. Detailed expressions of the Seiberg-Witten maps for the gauge parameters, gauge potentials, and the field strengths have been worked out. Our results demonstrate that notwithstanding the introduction of more general noncommutative structure there is no first order correction, exactly as happens for a canonical (i.e. constant) noncommutativity.

  16. Capillary deposition of advected floating particles

    Science.gov (United States)

    Dressaire, Emilie; Debaisieux, Aymeric; Gregori, Federico

    2016-11-01

    The deposition and aggregation of particles flowing through a confined environment can dramatically hinder the transport of suspensions. Yet, the mechanisms responsible for the deposition of particles in shear flow are not fully understood. Here, we use an experimental model system in which floating particles are advected on the surface of a water channel and deposited on fixed obstacles through attractive capillary effects. By varying the flow rate of the liquid, the wetting properties and size of the particles and obstacles, we can tune the magnitude of the capillary and hydrodynamic forces that determine the probability of deposition and the equilibrium position on the substrate. We show that arrays of obstacles can be designed to efficiently capture the floating particles advected by the flow.

  17. Onset of chaotic advection in open flows.

    Science.gov (United States)

    Biemond, J J Benjamin; de Moura, Alessandro P S; Károlyi, György; Grebogi, Celso; Nijmeijer, Henk

    2008-07-01

    In this paper we investigate the transition to chaos in the motion of particles advected by open flows with obstacles. By means of a topological argument, we show that the separation points on the surface of the obstacle imply the existence of a saddle point downstream from the obstacle, with an associated heteroclinic orbit. We argue that as soon as the flow becomes time periodic, these orbits give rise to heteroclinic tangles, causing passively advected particles to experience transient chaos. The transition to chaos thus coincides with the onset of time dependence in open flows with stagnant points, in contrast with flows with no stagnant points. We also show that the nonhyperbolic nature of the dynamics near the walls causes anomalous scalings in the vicinity of the transition. These results are confirmed by numerical simulations of the two-dimensional flow around a cylinder.

  18. Introduction to quantum Lie algebras

    CERN Document Server

    Delius, G W

    1996-01-01

    Quantum Lie algebras are generalizations of Lie algebras whose structure constants are power series in h. They are derived from the quantized enveloping algebras \\uqg. The quantum Lie bracket satisfies a generalization of antisymmetry. Representations of quantum Lie algebras are defined in terms of a generalized commutator. In this paper the recent general results about quantum Lie algebras are introduced with the help of the explicit example of (sl_2)_h.

  19. Lie groups, lie algebras, and representations an elementary introduction

    CERN Document Server

    Hall, Brian

    2015-01-01

    This textbook treats Lie groups, Lie algebras and their representations in an elementary but fully rigorous fashion requiring minimal prerequisites. In particular, the theory of matrix Lie groups and their Lie algebras is developed using only linear algebra, and more motivation and intuition for proofs is provided than in most classic texts on the subject. In addition to its accessible treatment of the basic theory of Lie groups and Lie algebras, the book is also noteworthy for including: a treatment of the Baker–Campbell–Hausdorff formula and its use in place of the Frobenius theorem to establish deeper results about the relationship between Lie groups and Lie algebras motivation for the machinery of roots, weights and the Weyl group via a concrete and detailed exposition of the representation theory of sl(3;C) an unconventional definition of semisimplicity that allows for a rapid development of the structure theory of semisimple Lie algebras a self-contained construction of the representations of compac...

  20. Distributed Parallel Particle Advection using Work Requesting

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Cornelius; Camp, David; Hentschel, Bernd; Garth, Christoph

    2013-09-30

    Particle advection is an important vector field visualization technique that is difficult to apply to very large data sets in a distributed setting due to scalability limitations in existing algorithms. In this paper, we report on several experiments using work requesting dynamic scheduling which achieves balanced work distribution on arbitrary problems with minimal communication overhead. We present a corresponding prototype implementation, provide and analyze benchmark results, and compare our results to an existing algorithm.

  1. High Order Semi-Lagrangian Advection Scheme

    Science.gov (United States)

    Malaga, Carlos; Mandujano, Francisco; Becerra, Julian

    2014-11-01

    In most fluid phenomena, advection plays an important roll. A numerical scheme capable of making quantitative predictions and simulations must compute correctly the advection terms appearing in the equations governing fluid flow. Here we present a high order forward semi-Lagrangian numerical scheme specifically tailored to compute material derivatives. The scheme relies on the geometrical interpretation of material derivatives to compute the time evolution of fields on grids that deform with the material fluid domain, an interpolating procedure of arbitrary order that preserves the moments of the interpolated distributions, and a nonlinear mapping strategy to perform interpolations between undeformed and deformed grids. Additionally, a discontinuity criterion was implemented to deal with discontinuous fields and shocks. Tests of pure advection, shock formation and nonlinear phenomena are presented to show performance and convergence of the scheme. The high computational cost is considerably reduced when implemented on massively parallel architectures found in graphic cards. The authors acknowledge funding from Fondo Sectorial CONACYT-SENER Grant Number 42536 (DGAJ-SPI-34-170412-217).

  2. Discrete Variational Optimal Control

    CERN Document Server

    Jimenez, Fernando; de Diego, David Martin

    2012-01-01

    This paper develops numerical methods for optimal control of mechanical systems in the Lagrangian setting. It extends the theory of discrete mechanics to enable the solutions of optimal control problems through the discretization of variational principles. The key point is to solve the optimal control problem as a variational integrator of a specially constructed higher-dimensional system. The developed framework applies to systems on tangent bundles, Lie groups, underactuated and nonholonomic systems with symmetries, and can approximate either smooth or discontinuous control inputs. The resulting methods inherit the preservation properties of variational integrators and result in numerically robust and easily implementable algorithms. Several theoretical and a practical examples, e.g. the control of an underwater vehicle, will illustrate the application of the proposed approach.

  3. Discrete Variational Optimal Control

    Science.gov (United States)

    Jiménez, Fernando; Kobilarov, Marin; Martín de Diego, David

    2013-06-01

    This paper develops numerical methods for optimal control of mechanical systems in the Lagrangian setting. It extends the theory of discrete mechanics to enable the solutions of optimal control problems through the discretization of variational principles. The key point is to solve the optimal control problem as a variational integrator of a specially constructed higher dimensional system. The developed framework applies to systems on tangent bundles, Lie groups, and underactuated and nonholonomic systems with symmetries, and can approximate either smooth or discontinuous control inputs. The resulting methods inherit the preservation properties of variational integrators and result in numerically robust and easily implementable algorithms. Several theoretical examples and a practical one, the control of an underwater vehicle, illustrate the application of the proposed approach.

  4. Asynchronous discrete event schemes for PDEs

    Science.gov (United States)

    Stone, D.; Geiger, S.; Lord, G. J.

    2017-08-01

    A new class of asynchronous discrete-event simulation schemes for advection-diffusion-reaction equations is introduced, based on the principle of allowing quanta of mass to pass through faces of a (regular, structured) Cartesian finite volume grid. The timescales of these events are linked to the flux on the face. The resulting schemes are self-adaptive, and local in both time and space. Experiments are performed on realistic physical systems related to porous media flow applications, including a large 3D advection diffusion equation and advection diffusion reaction systems. The results are compared to highly accurate reference solutions where the temporal evolution is computed with exponential integrator schemes using the same finite volume discretisation. This allows a reliable estimation of the solution error. Our results indicate a first order convergence of the error as a control parameter is decreased, and we outline a framework for analysis.

  5. The fundamental solution and numerical solution of the Riesz fractional advection-dispersion equation

    Science.gov (United States)

    Shen, S.; Liu, F.; Anh, V.; Turner, I.

    2008-12-01

    In this paper, we consider a Riesz fractional advection-dispersion equation (RFADE), which is derived from the kinetics of chaotic dynamics. The RFADE is obtained from the standard advection-dispersion equation by replacing the first-order and second-order space derivatives by the Riesz fractional derivatives of order{alpha} [isin] (0, 1) and {beta} [isin] (1, 2], respectively. We derive the fundamental solution for the Riesz fractional advection-dispersion equation with an initial condition (RFADE-IC). We investigate a discrete random walk model based on an explicit finite-difference approximation for the RFADE-IC and prove that the random walk model belongs to the domain of attraction of the corresponding stable distribution. We also present explicit and implicit difference approximations for the Riesz fractional advection-dispersion equation with initial and boundary conditions (RFADE-IBC) in a finite domain. Stability and convergence of these numerical methods for the RFADE-IBC are discussed. Some numerical examples are given to show that the numerical results are in good agreement with our theoretical analysis.

  6. Development of Multigrid Methods for diffusion, Advection, and the incompressible Navier-Stokes Equations

    Energy Technology Data Exchange (ETDEWEB)

    Gjesdal, Thor

    1997-12-31

    This thesis discusses the development and application of efficient numerical methods for the simulation of fluid flows, in particular the flow of incompressible fluids. The emphasis is on practical aspects of algorithm development and on application of the methods either to linear scalar model equations or to the non-linear incompressible Navier-Stokes equations. The first part deals with cell centred multigrid methods and linear correction scheme and presents papers on (1) generalization of the method to arbitrary sized grids for diffusion problems, (2) low order method for advection-diffusion problems, (3) attempt to extend the basic method to advection-diffusion problems, (4) Fourier smoothing analysis of multicolour relaxation schemes, and (5) analysis of high-order discretizations for advection terms. The second part discusses a multigrid based on pressure correction methods, non-linear full approximation scheme, and papers on (1) systematic comparison of the performance of different pressure correction smoothers and some other algorithmic variants, low to moderate Reynolds numbers, and (2) systematic study of implementation strategies for high order advection schemes, high-Re flow. An appendix contains Fortran 90 data structures for multigrid development. 160 refs., 26 figs., 22 tabs.

  7. Discrete Stein characterizations and discrete information distances

    CERN Document Server

    Ley, Christophe

    2012-01-01

    We construct two different Stein characterizations of discrete distributions and use these to provide a natural connection between Stein characterizations for discrete distributions and discrete information functionals.

  8. Lie algebraic Noncommutative Gravity

    CERN Document Server

    Banerjee, R; Samanta, S; Banerjee, Rabin; Mukherjee, Pradip; Samanta, Saurav

    2007-01-01

    The minimal (unimodular) formulation of noncommutative general relativity, based on gauging the Poincare group, is extended to a general Lie algebra valued noncommutative structure. We exploit the Seiberg -- Witten map technique to formulate the theory as a perturbative Lagrangian theory. Detailed expressions of the Seiberg -- Witten maps for the gauge parameters, gauge potentials and the field strengths have been worked out. Our results demonstrate that notwithstanding the introduction of more general noncommutative structure there is no first order correction, exactly as happens for a canonical (i.e. constant) noncommutativity.

  9. Lied Transplant Center

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Department of Energy has prepared an Environmental Assessment (DOE/EA-1143) evaluating the construction, equipping and operation of the proposed Lied Transplant Center at the University of Nebraska Medical Center in Omaha, Nebraska. Based on the analysis in the EA, the DOE has determined that the proposed action does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an Environmental Statement in not required.

  10. New Applications of a Kind of Infinitesimal-Operator Lie Algebra

    Directory of Open Access Journals (Sweden)

    Honwah Tam

    2016-01-01

    Full Text Available Applying some reduced Lie algebras of Lie symmetry operators of a Lie transformation group, we obtain an invariant of a second-order differential equation which can be generated by a Euler-Lagrange formulism. A corresponding discrete equation approximating it is given as well. Finally, we make use of the Lie algebras to generate some new integrable systems including (1+1 and (2+1 dimensions.

  11. Police lie detection accuracy: the effect of lie scenario.

    Science.gov (United States)

    O'Sullivan, Maureen; Frank, Mark G; Hurley, Carolyn M; Tiwana, Jaspreet

    2009-12-01

    Although most people are not better than chance in detecting deception, some groups of police professionals have demonstrated significant lie detection accuracy. One reason for this difference may be that the types of lies police are asked to judge in scientific experiments often do not represent the types of lies they see in their profession. Across 23 studies, involving 31 different police groups in eight countries, police officers tested with lie detection scenarios using high stakes lies (i.e., the lie was personally involving and/or resulted in substantial rewards or punishments for the liar) were significantly more accurate than law enforcement officials tested with low stakes lies. Face validity and construct validity of various lie scenarios are differentiated.

  12. Discrete Mathematics

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    The introduction of the mathematics needed for analysis, design and verification of discrete systems, including applications within programming languages for computer systems. Course sessions and project work. Semester: Spring 2010 Ectent: 5 ects Class size: 18......The introduction of the mathematics needed for analysis, design and verification of discrete systems, including applications within programming languages for computer systems. Course sessions and project work. Semester: Spring 2010 Ectent: 5 ects Class size: 18...

  13. Discrete Mathematics

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2010-01-01

    The introduction of the mathematics needed for analysis, design and verification of discrete systems, including applications within programming languages for computer systems. Course sessions and project work. Semester: Autumn 2010 Ectent: 5 ects Class size: 15......The introduction of the mathematics needed for analysis, design and verification of discrete systems, including applications within programming languages for computer systems. Course sessions and project work. Semester: Autumn 2010 Ectent: 5 ects Class size: 15...

  14. Construction of Difference Equations Using Lie Groups

    Energy Technology Data Exchange (ETDEWEB)

    Axford, R.A.

    1998-08-01

    The theory of prolongations of the generators of groups of point transformations to the grid point values of dependent variables and grid spacings is developed and applied to the construction of group invariant numerical algorithms. The concepts of invariant difference operators and generalized discrete sources are introduced for the discretization of systems of inhomogeneous differential equations and shown to produce exact difference equations. Invariant numerical flux functions are constructed from the general solutions of first order partial differential equations that come out of the evaluation of the Lie derivatives of conservation forms of difference schemes. It is demonstrated that invariant numerical flux functions with invariant flux or slope limiters can be determined to yield high resolution difference schemes. The introduction of an invariant flux or slope limiter can be done so as not to break the symmetry properties of a numerical flux-function.

  15. [Diagnostic imaging of lying].

    Science.gov (United States)

    Lass, Piotr; Sławek, Jarosław; Sitek, Emilia; Szurowska, Edyta; Zimmermann, Agnieszka

    2013-01-01

    Functional diagnostic imaging has been applied in neuropsychology for more than two decades. Nowadays, the functional magnetic resonance (fMRI) seems to be the most important technique. Brain imaging in lying has been performed and discussed since 2001. There are postulates to use fMRI for forensic purposes, as well as commercially, e.g. testing the loyalty of employees, especially because of the limitations of traditional polygraph in some cases. In USA fMRI is performed in truthfulness/lying assessment by at least two commercial companies. Those applications are a matter of heated debate of practitioners, lawyers and specialists of ethics. The opponents of fMRI use for forensic purposes indicate the lack of common agreement on it and the lack of wide recognition and insufficient standardisation. Therefore it cannot serve as a forensic proof, yet. However, considering the development of MRI and a high failure rate of traditional polygraphy, forensic applications of MRI seem to be highly probable in future.

  16. Telling Lies: The Irrepressible Truth?

    Science.gov (United States)

    Williams, Emma J.; Bott, Lewis A.; Patrick, John; Lewis, Michael B.

    2013-01-01

    Telling a lie takes longer than telling the truth but precisely why remains uncertain. We investigated two processes suggested to increase response times, namely the decision to lie and the construction of a lie response. In Experiments 1 and 2, participants were directed or chose whether to lie or tell the truth. A colored square was presented and participants had to name either the true color of the square or lie about it by claiming it was a different color. In both experiments we found that there was a greater difference between lying and telling the truth when participants were directed to lie compared to when they chose to lie. In Experiments 3 and 4, we compared response times when participants had only one possible lie option to a choice of two or three possible options. There was a greater lying latency effect when questions involved more than one possible lie response. Experiment 5 examined response choice mechanisms through the manipulation of lie plausibility. Overall, results demonstrate several distinct mechanisms that contribute to additional processing requirements when individuals tell a lie. PMID:23573277

  17. Discrete integrable couplings associated with modified Korteweg-de Vries lattice and two hierarchies of discrete soliton equations

    Institute of Scientific and Technical Information of China (English)

    Dong Huan-He

    2007-01-01

    A direct way to construct integrable couplings for discrete systems is presented by use of two semi-direct sum Lie algebras. As their applications, the discrete integrable couplings associated with modified Korteweg-de Vries (m-KdV) lattice and two hierarchies of discrete soliton equations are developed. It is also indicated that the study of integrable couplings using semi-direct sums of Lie algebras is an important step towards the complete classification of integrable couplings.

  18. A balancing domain decomposition method by constraints for advection-diffusion problems

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Xuemin; Li, Jing

    2008-12-10

    The balancing domain decomposition methods by constraints are extended to solving nonsymmetric, positive definite linear systems resulting from the finite element discretization of advection-diffusion equations. A pre-conditioned GMRES iteration is used to solve a Schur complement system of equations for the subdomain interface variables. In the preconditioning step of each iteration, a partially sub-assembled finite element problem is solved. A convergence rate estimate for the GMRES iteration is established, under the condition that the diameters of subdomains are small enough. It is independent of the number of subdomains and grows only slowly with the subdomain problem size. Numerical experiments for several two-dimensional advection-diffusion problems illustrate the fast convergence of the proposed algorithm.

  19. A condensed-mass advection based model for the simulation of liquid polar stratospheric clouds

    Directory of Open Access Journals (Sweden)

    D. Lowe

    2002-06-01

    Full Text Available We present a condensed-mass advection based model (MADVEC designed to simulate the condensation/evaporation of liquid polar stratospheric cloud (PSC particles. A (Eulerian-in-radius discretization scheme is used, making the model suitable for use in global or mesoscale chemistry and transport models (CTMs. The mass advection equations are solved using an adaption of the weighted average flux (WAF scheme. We validate the numerical scheme using an analytical solution for multicomponent aerosols. The physics of the model are tested using a test case designed by Meilinger et al. (1995. The results from this test corroborate the composition gradients across the size distribution under rapid cooling conditions that were reported in earlier studies.

  20. Group discussion improves lie detection

    National Research Council Canada - National Science Library

    Nadav Klein; Nicholas Epley

    2015-01-01

    ... identify when a person is lying. These experiments demonstrate that the group advantage in lie detection comes through the process of group discussion, and is not a product of aggregating individual opinions...

  1. Lying because we care: Compassion increases prosocial lying.

    Science.gov (United States)

    Lupoli, Matthew J; Jampol, Lily; Oveis, Christopher

    2017-07-01

    Prosocial lies, or lies intended to benefit others, are ubiquitous behaviors that have important social and economic consequences. Though emotions play a central role in many forms of prosocial behavior, no work has investigated how emotions influence behavior when one has the opportunity to tell a prosocial lie-a situation that presents a conflict between two prosocial ethics: lying to prevent harm to another, and honesty, which might also provide benefits to the target of the lie. Here, we examine whether the emotion of compassion influences prosocial lying, and find that compassion causally increases and positively predicts prosocial lying. In Studies 1 and 2, participants evaluated a poorly written essay and provided feedback to the essay writer. Experimentally induced compassion felt toward the essay writer (Study 1) and individual differences in trait compassion (Study 2) were positively associated with inflated feedback to the essay writer. In both of these studies, the relationship between compassion and prosocial lying was partially mediated by an enhanced importance placed on preventing emotional harm. In Study 3, we found moderation such that experimentally induced compassion increased lies that resulted in financial gains for a charity, but not lies that produced financial gains for the self. This research illuminates the emotional underpinnings of the common yet morally complex behavior of prosocial lying, and builds on work highlighting the potentially harmful effects of compassion-an emotion typically seen as socially beneficial. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. On the Logic of Lying

    NARCIS (Netherlands)

    H. van Ditmarsch (Hans); D.J.N. van Eijck (Jan); F.A.G. Sietsma (Floor)

    2012-01-01

    textabstractWe model lying as a communicative act changing the beliefs of the agents in a multi-agent system. With Augustine, we see lying as an utterance believed to be false by the speaker and uttered with the intent to deceive the addressee. The deceit is successful if the lie is believed

  3. Lying relies on the truth

    NARCIS (Netherlands)

    Debey, E.; De Houwer, J.; Verschuere, B.

    2014-01-01

    Cognitive models of deception focus on the conflict-inducing nature of the truth activation during lying. Here we tested the counterintuitive hypothesis that the truth can also serve a functional role in the act of lying. More specifically, we examined whether the construction of a lie can involve a

  4. Lying relies on the truth

    NARCIS (Netherlands)

    Debey, E.; De Houwer, J.; Verschuere, B.

    2014-01-01

    Cognitive models of deception focus on the conflict-inducing nature of the truth activation during lying. Here we tested the counterintuitive hypothesis that the truth can also serve a functional role in the act of lying. More specifically, we examined whether the construction of a lie can involve a

  5. Pre-Lie Deformation Theory

    NARCIS (Netherlands)

    Dotsenko, V.; Shadrin, S.; Vallette, B.

    2016-01-01

    In this paper, we develop the deformation theory controlled by pre-Lie algebras; the main tool is a new integration theory for preLie algebras. The main field of application lies in homotopy algebra structures over a Koszul operad; in this case, we provide a homotopical description of the associated

  6. Semi-analytical solution of the steady three-dimensional advection-diffusion equation in the planetary boundary layer

    Science.gov (United States)

    Costa, C. P.; Vilhena, M. T.; Moreira, D. M.; Tirabassi, T.

    We present a three-dimensional solution of the steady-state advection-diffusion equation considering a vertically inhomogeneous planetary boundary layer (PBL). We reach this goal applying the generalized integral transform technique (GITT), a hybrid method that had solved a wide class of direct and inverse problems mainly in the area of heat transfer and fluid mechanics. The transformed problem is solved by the advection-diffusion multilayer model (ADMM) method, a semi-analytical solution based on a discretization of the PBL in sub-layers where the advection-diffusion equation is solved by the Laplace transform technique. Numerical simulations are presented and the performances of the solution are compared against field experiments data.

  7. Novel Second-Order Accurate Implicit Numerical Methods for the Riesz Space Distributed-Order Advection-Dispersion Equations

    Directory of Open Access Journals (Sweden)

    X. Wang

    2015-01-01

    Full Text Available We derive and analyze second-order accurate implicit numerical methods for the Riesz space distributed-order advection-dispersion equations (RSDO-ADE in one-dimensional (1D and two-dimensional (2D cases, respectively. Firstly, we discretize the Riesz space distributed-order advection-dispersion equations into multiterm Riesz space fractional advection-dispersion equations (MT-RSDO-ADE by using the midpoint quadrature rule. Secondly, we propose a second-order accurate implicit numerical method for the MT-RSDO-ADE. Thirdly, stability and convergence are discussed. We investigate the numerical solution and analysis of the RSDO-ADE in 1D case. Then we discuss the RSDO-ADE in 2D case. For 2D case, we propose a new second-order accurate implicit alternating direction method, and the stability and convergence of this method are proved. Finally, numerical results are presented to support our theoretical analysis.

  8. Parallel algorithms for semi-lagrangian advection

    Science.gov (United States)

    Malevsky, A. V.; Thomas, S. J.

    1997-08-01

    Numerical time step limitations associated with the explicit treatment of advection-dominated problems in computational fluid dynamics are often relaxed by employing Eulerian-Lagrangian methods. These are also known as semi-Lagrangian methods in the atmospheric sciences. Such methods involve backward time integration of a characteristic equation to find the departure point of a fluid particle arriving at a Eulerian grid point. The value of the advected field at the departure point is obtained by interpolation. Both the trajectory integration and repeated interpolation influence accuracy. We compare the accuracy and performance of interpolation schemes based on piecewise cubic polynomials and cubic B-splines in the context of a distributed memory, parallel computing environment. The computational cost and interprocessor communication requirements for both methods are reported. Spline interpolation has better conservation properties but requires the solution of a global linear system, initially appearing to hinder a distributed memory implementation. The proposed parallel algorithm for multidimensional spline interpolation has almost the same communication overhead as local piecewise polynomial interpolation. We also compare various techniques for tracking trajectories given different values for the Courant number. Large Courant numbers require a high-order ODE solver involving multiple interpolations of the velocity field.

  9. Striated populations in disordered environments with advection

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.; Succi, Sauro

    2017-01-01

    Growth in static and controlled environments such as a Petri dish can be used to study the spatial population dynamics of microorganisms. However, natural populations such as marine microbes experience fluid advection and often grow up in heterogeneous environments. We investigate a generalized Fisher-Kolmogorov-Petrovsky-Piscounov (FKPP) equation describing single species population subject to a constant flow field and quenched random spatially inhomogeneous growth rates with a fertile overall growth condition. We analytically and numerically demonstrate that the non-equilibrium steady-state population density develops a flow-driven striation pattern. The striations are highly asymmetric with a longitudinal correlation length that diverges linearly with the flow speed and a transverse correlation length that approaches a finite velocity-independent value. Linear response theory is developed to study the statistics of the steady states. Theoretical predictions show excellent agreement with the numerical steady states of the generalized FKPP equation obtained from Lattice Boltzmann simulations. These findings suggest that, although the growth disorder can be spatially uncorrelated, correlated population structures with striations emerge naturally at sufficiently strong advection.

  10. A computational method for sharp interface advection

    Science.gov (United States)

    Roenby, Johan; Bredmose, Henrik; Jasak, Hrvoje

    2016-11-01

    We devise a numerical method for passive advection of a surface, such as the interface between two incompressible fluids, across a computational mesh. The method is called isoAdvector, and is developed for general meshes consisting of arbitrary polyhedral cells. The algorithm is based on the volume of fluid (VOF) idea of calculating the volume of one of the fluids transported across the mesh faces during a time step. The novelty of the isoAdvector concept consists of two parts. First, we exploit an isosurface concept for modelling the interface inside cells in a geometric surface reconstruction step. Second, from the reconstructed surface, we model the motion of the face-interface intersection line for a general polygonal face to obtain the time evolution within a time step of the submerged face area. Integrating this submerged area over the time step leads to an accurate estimate for the total volume of fluid transported across the face. The method was tested on simple two-dimensional and three-dimensional interface advection problems on both structured and unstructured meshes. The results are very satisfactory in terms of volume conservation, boundedness, surface sharpness and efficiency. The isoAdvector method was implemented as an OpenFOAM extension and is published as open source.

  11. A Computational Method for Sharp Interface Advection

    CERN Document Server

    Roenby, Johan; Jasak, Hrvoje

    2016-01-01

    We devise a numerical method for passive advection of a surface, such as the interface between two incompressible fluids, across a computational mesh. The method is called isoAdvector, and is developed for general meshes consisting of arbitrary polyhedral cells. The algorithm is based on the volume of fluid (VOF) idea of calculating the volume of one of the fluids transported across the mesh faces during a time step. The novelty of the isoAdvector concept consists in two parts: First, we exploit an isosurface concept for modelling the interface inside cells in a geometric surface reconstruction step. Second, from the reconstructed surface, we model the motion of the face-interface intersection line for a general polygonal face to obtain the time evolution within a time step of the submerged face area. Integrating this submerged area over the time step leads to an accurate estimate for the total volume of fluid transported across the face. The method was tested on simple 2D and 3D interface advection problems ...

  12. Quantization on nilpotent Lie groups

    CERN Document Server

    Fischer, Veronique

    2016-01-01

    This book presents a consistent development of the Kohn-Nirenberg type global quantization theory in the setting of graded nilpotent Lie groups in terms of their representations. It contains a detailed exposition of related background topics on homogeneous Lie groups, nilpotent Lie groups, and the analysis of Rockland operators on graded Lie groups together with their associated Sobolev spaces. For the specific example of the Heisenberg group the theory is illustrated in detail. In addition, the book features a brief account of the corresponding quantization theory in the setting of compact Lie groups. The monograph is the winner of the 2014 Ferran Sunyer i Balaguer Prize.

  13. Discrete Chaos

    CERN Document Server

    Waelbroeck, H

    1999-01-01

    We propose a theory of deterministic chaos for discrete systems, based on their representations in symbolic history spaces Ømega. These are spaces of semi-infinite sequences, as the one-sided shift spaces, but endowed with a more general topology which we call a semicausal topology. We show that define metrical properties, including the correlation dimension of the attractor. Examples are considered: Asymmetric neural networks and random cellular automata are not chaotic. A neural network model with memory, on the other hand, does appear to be an example of discrete chaos.

  14. Discrete mechanics

    CERN Document Server

    Caltagirone, Jean-Paul

    2014-01-01

    This book presents the fundamental principles of mechanics to re-establish the equations of Discrete Mechanics. It introduces physics and thermodynamics associated to the physical modeling.  The development and the complementarity of sciences lead to review today the old concepts that were the basis for the development of continuum mechanics. The differential geometry is used to review the conservation laws of mechanics. For instance, this formalism requires a different location of vector and scalar quantities in space. The equations of Discrete Mechanics form a system of equations where the H

  15. Territorial discretion

    Directory of Open Access Journals (Sweden)

    Augusto Hernández Vidal

    2011-12-01

    Full Text Available In order to strengthen the concept of municipal autonomy, this essay proposes an extensive interpretation of administrative discretion. Discretion is the exercise of free judgment given by law to authorities for performing official acts. This legislative technique seems to be suitable whenever the legislative is intended to legislate over the essential core of municipal autonomy. This way, an eventual abuse of that autonomy could be avoided, for the disproportional restriction of the local faculty to oversee the local issues. This alternative is presented as a tool to provide with dynamism the performing of administrative activities as well, aiming to assimilate public administration new practices.

  16. Study of a model for correcting the effects of horizontal advection on surface fluxes measurement based on remote sensing

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>As well known, the methods of remote sensing and Bowen Ratio for retrieving surface flux are based on energy balance closure; however, in most cases, surface energy observed in experiment is lack of closure. There are two main causes for this: one is from the errors of the observation devices and the differences of their observational scale; the other lies in the effect of horizontal advection on the surface flux measurement. Therefore, it is very important to estimate the effects of horizontal advection quantitatively. Based on the local advection theory and the surface experiment, a model has been proposed for correcting the effect of horizontal advection on surface flux measurement, in which the relationship between the fetch of the measurement and pixel size for remote sensed data was considered. By means of numerical simulations, the sensitivities of the main parameters in the model and the scaling problems of horizontal advection were analyzed. At last, by using the observational data acquired in agricultural field with relatively homogeneous surface, the model was validated.

  17. A numerical scheme for space-time fractional advection-dispersion equation

    CERN Document Server

    Javadi, S; Jani, M

    2015-01-01

    In this paper, we develop a numerical resolution of the space-time fractional advection-dispersion equation. After time discretization, we utilize collocation technique and implement a product integration method in order to simplify the evaluation of the terms involving spatial fractional order derivatives. Then utilizing Bernstein polynomials as basis, the problem is transformed into a linear system of algebraic equations. Error analysis and order of convergence for the proposed method are also discussed. Some numerical experiments are presented to demonstrate the effectiveness of the proposed method and to confirm the analytic results.

  18. Lie Subalgebras in a Certain Operator Lie Algebra with Involution

    Institute of Scientific and Technical Information of China (English)

    Shan Li SUN; Xue Feng MA

    2011-01-01

    We show in a certain Lie'-algebra,the connections between the Lie subalgebra G+:=G+G*+[G,G*],generated by a Lie subalgebra G,and the properties of G.This allows us to investigate some useful information about the structure of such two Lie subalgebras.Some results on the relations between the two Lie subalgebras are obtained.As an application,we get the following conclusion:Let A (∪) B(X)be a space of self-adjoint operators and L:=A ⊕ iA the corresponding complex Lie*-algebra.G+=G+G*+[G,G*]and G are two LM-decomposable Lie subalgebras of,L with the decomposition G+=R(G+)+S,G=RG+SG,and RG (∪) R(C+).Then G+ is ideally finite iff RG+:=RG+RG*+[RG,RG*]is a quasisolvable Lie subalgebra,SG+:=SG+SG*+[SG,SG*]is an ideally finite semisimple Lie subalgebra,and [RG,SG]=[RG*,SG]={0}.

  19. Neural correlates of telling lies: A functional magnetic resonance imaging study at 4 tesla

    NARCIS (Netherlands)

    Phan, K.L.; Magalhaes, A.; Ziemlewicz, T.J.; Fitzgerald, D.A.; Green, C.; Smith, W.

    2005-01-01

    Rationale and objective - Intentional deception (ie, lying) is a complex cognitive act, with important legal, moral, political, and economic implications. Prior studies have identified activation of discrete anterior frontal regions, such as the ventrolateral prefrontal cortex (VLPFC), dorsolateral

  20. Hamiltonian Forms for a Hierarchy of Discrete Integrable Coupling Systems

    Institute of Scientific and Technical Information of China (English)

    XU Xi-Xiang; YANG Hong-Xiang; LU Rong-Wu

    2008-01-01

    A semi-direct sum of two Lie algebras of four-by-four matrices is presented, and a discrete four-by-fore matrix spectral problem is introduced. A hierarchy of discrete integrable coupling systems is derived. The obtained integrable coupling systems are all written in their Hamiltonian forms by the discrete variational identity. Finally, we prove that the lattice equations in the obtained integrable coupling systems are all Liouville integrable discrete Hamiltonian systems.

  1. A computational method for sharp interface advection

    DEFF Research Database (Denmark)

    Roenby, Johan; Bredmose, Henrik; Jasak, Hrvoje

    2016-01-01

    We devise a numerical method for passive advection of a surface, such as the interface between two incompressible fluids, across a computational mesh. The method is called isoAdvector, and is developed for general meshes consisting of arbitrary polyhedral cells. The algorithm is based on the volume...... of fluid (VOF) idea of calculating the volume of one of the fluids transported across the mesh faces during a time step. The novelty of the isoAdvector concept consists of two parts. First, we exploit an isosurface concept for modelling the interface inside cells in a geometric surface reconstruction step....... Second, from the reconstructed surface, we model the motion of the face–interface intersection line for a general polygonal face to obtain the time evolution within a time step of the submerged face area. Integrating this submerged area over the time step leads to an accurate estimate for the total...

  2. Cellwise conservative unsplit advection for the volume of fluid method

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    2015-01-01

    We present a cellwise conservative unsplit (CCU) advection scheme for the volume of fluid method (VOF) in 2D. Contrary to other schemes based on explicit calculations of the flux balances, the CCU advection adopts a cellwise approach where the pre-images of the control volumes are traced backward......We present a cellwise conservative unsplit (CCU) advection scheme for the volume of fluid method (VOF) in 2D. Contrary to other schemes based on explicit calculations of the flux balances, the CCU advection adopts a cellwise approach where the pre-images of the control volumes are traced...

  3. Lie groups and automorphic forms

    CERN Document Server

    Ji, Lizhen; Xu, H W; Yau, Shing-Tung

    2006-01-01

    Lie groups are fundamental objects in mathematics. They occur naturally in differential geometry, algebraic geometry, representation theory, number theory, and other areas. Closely related are arithmetic subgroups, locally symmetric spaces and the spectral theory of automorphic forms. This book consists of five chapters which give comprehensive introductions to Lie groups, Lie algebras, arithmetic groups and reduction theories, cohomology of arithmetic groups, and the Petersson and Kuznetsov trace formulas.

  4. Discrete Mathematics

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    2011-01-01

    examples on regular languages. Apply these concepts to new problems. Finite state machines: Define a finite state machine as a 6-tuble; describe simple finite state machines by tables and graphs; pattern recognition by finite state machines; minimizing the number of states in a finite state machine......The objectives of Discrete Mathematics (IDISM2) are: The introduction of the mathematics needed for analysis, design and verification of discrete systems, including the application within programming languages for computer systems. Having passed the IDISM2 course, the student will be able...... of natural numbers. Apply these concepts to new problems. Division and factorizing: Define a prime number and apply Euclid´s algorithm for factorizing an integer. Regular languages: Define a language from the elements of a set; define a regular language; form strings from a regular language; construct...

  5. Bosonization and Lie Group Structure

    CERN Document Server

    Ha, Yuan K

    2015-01-01

    We introduce a concise quantum operator formula for bosonization in which the Lie group structure appears in a natural way. The connection between fermions and bosons is found to be exactly the connection between Lie group elements and the group parameters. Bosonization is an extraordinary way of expressing the equation of motion of a complex fermion field in terms of a real scalar boson in two dimensions. All the properties of the fermion field theory are known to be preserved under this remarkable transformation with substantial simplification and elucidation of the original theory, much like Lie groups can be studied by their Lie algebras.

  6. Lying relies on the truth.

    Science.gov (United States)

    Debey, Evelyne; De Houwer, Jan; Verschuere, Bruno

    2014-09-01

    Cognitive models of deception focus on the conflict-inducing nature of the truth activation during lying. Here we tested the counterintuitive hypothesis that the truth can also serve a functional role in the act of lying. More specifically, we examined whether the construction of a lie can involve a two-step process, where the first step entails activating the truth, based upon which a lie response can be formulated in a second step. To investigate this hypothesis, we tried to capture the covert truth activation in a reaction-time based deception paradigm. Together with each question, we presented either the truth or lie response as distractors. If lying depends on the covert activation of the truth, deceptive responses would thus be facilitated by truth distractors relative to lie distractors. Our results indeed revealed such a "covert congruency" effect, both in errors and reaction times (Experiment 1). Moreover, stimulating participants to use the distractor information by increasing the proportion of truth distractor trials enlarged the "covert congruency" effects, and as such confirmed that the effects operate at a covert response level (Experiment 2). Our findings lend support to the idea that lying relies on a first step of truth telling, and call for a shift in theoretical thinking that highlights both the functional and interfering properties of the truth activation in the lying process. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Differential geometry on Lie groups

    OpenAIRE

    2013-01-01

    Resumo: Neste trabalho estudamos os aspectos geométricos dos grupos de Lie do ponto de vista da geometria Riemanniana, geometria Hermitiana e geometria Kähler, através das estruturas geométricas invariantes associadas. Exploramos resultados relacionados às curvaturas da variedade Riemanniana subjacente a um grupo de Lie através do estudo de sua álgebra de Lie correspondente. No contexto da geometria Hermitiana e geometria Kähler, para um caso concreto de grupo de Lie complexo, investigaram su...

  8. Affective Priming Caused by Lying

    Directory of Open Access Journals (Sweden)

    Megumi Sato

    2011-10-01

    Full Text Available Typically, arousal increases when telling a lie, as indicated in psychophysiological studies about lie detection. But the emotional valence induced by lying is unknown, though intuition indicates that it may be negative. Indeed, the Electrodermal Activity (EDA, used in such studies, only shows arousal changes during an emotional response. In this study, we examined the emotional valence induced by lying using two tasks. First, in the deceptive task, participants answered “no” to every question regarding the nature of displayed playing cards. Therefore, they told a lie about specific cards. During the task, their EDA was recorded. Secondly, in the figure estimation task, they assessed pictures by “like” or “dislike” after looking at playing cards visibly or subliminally as prime stimuli. We expected them to tend to estimate figures by “dislike” when cards relevant to deception were previously shown. This would mean that an affective priming effect due to telling a lie happened. Actually, this effect was found only when prime stimuli were displayed visibly. This result suggests that lying per se induces negative emotions even without motivation or punishment due to lying. Furthermore, we found that such effect was more blatant in participants whose EDA changes were salient while lying.

  9. A Lie based 4-dimensional higher Chern-Simons theory

    CERN Document Server

    Zucchini, Roberto

    2015-01-01

    We present and study a model of 4-dimensional higher Chern-Simons theory, special Chern-Simons (SCS) theory, instances of which have appeared in the string literature, whose symmetry is encoded in a skeletal semistrict Lie 2-algebra constructed from a compact Lie group with non discrete center. The field content of SCS theory consists of a Lie valued 2-connection coupled to a background closed 3-form. SCS theory enjoys a large gauge and gauge for gauge symmetry organized in an infinite dimensional strict Lie 2-group. The partition function of SCS theory is simply related to that of a topological gauge theory localizing on flat connections with degree 3 second characteristic class determined by the background 3-form. Finally, SCS theory is related to a 3-dimensional special gauge theory whose 2-connection space has a natural symplectic structure with respect to which the 1-gauge transformation action is Hamiltonian, the 2-curvature map acting as moment map.

  10. Theatres of the lie: 'crazy' deception and lying as drama.

    Science.gov (United States)

    Dongen, Els van

    2002-08-01

    In this article, the author argues that lying is drama, theatre, which brings about transition, reflection, reversal and involvement of the participants in the drama. By means of ethnographic data of a psychiatric ward, the author shows that lying of mental patients is not pathological, but a ritual of affliction. By using Turner's theory about rituals and performance and Goffman's theory about presentation of the self it will be showed that lying serves the redefinition of reciprocity and solidarity. With the help of Bakhtin's work on Rabelais, the author discusses the nature of the drama of the lie. It is concluded that a perspective on lying as theatre may be of use outside psychiatric wards and will occur in imbalanced power relationships.

  11. Combination of activity and lying/standing data for detection of oestrus in cows

    DEFF Research Database (Denmark)

    Jónsson, Ragnar Ingi; Blanke, Mogens; Poulsen, Niels Kjølstad

    2009-01-01

    is measured by a sensor attached to the hind leg of the cow. Activity and lying/standing behaviour are modelled as a discrete event system, constructed using automata theory. In an attempt to estimate a biologically relevant lying balance, a lying balance indicator is constructed and is influencing transition......The objective of this study is to develop an algorithm for detecting oestrus in dairy cows from measurements of activity and duration of lying/standing periods. Each cows activity is measured by a sensor attached to the neck that returns an activity index for each hour. Duration of lying...

  12. A high-order discontinuous Galerkin method for unsteady advection-diffusion problems

    Science.gov (United States)

    Borker, Raunak; Farhat, Charbel; Tezaur, Radek

    2017-03-01

    A high-order discontinuous Galerkin method with Lagrange multipliers is presented for the solution of unsteady advection-diffusion problems in the high Péclet number regime. It operates directly on the second-order form of the governing equation and does not require any stabilization. Its spatial basis functions are chosen among the free-space solutions of the homogeneous form of the partial differential equation obtained after time-discretization. It also features Lagrange multipliers for enforcing a weak continuity of the approximated solution across the element interface boundaries. This leads to a system of differential-algebraic equations which are time-integrated by an implicit family of schemes. The numerical stability of these schemes and the well-posedness of the overall discretization method are supported by a theoretical analysis. The performance of this method is demonstrated for various high Péclet number constant-coefficient model flow problems.

  13. Deciding isomorphism of Lie algebras

    NARCIS (Netherlands)

    Graaf, W.A. de

    2001-01-01

    When doing calculations with Lie algebras one of the main problems is to decide whether two given Lie algebras are isomorphic. A partial solution to this problem is obtained by calculating structural invariants. There is also a direct method available which involves the computation of Grobner bases.

  14. The low lying glueball spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Adam Szczepaniak; Eric Swanson

    2003-12-18

    The complete low-lying positive charge conjugation glueball spectrum is obtained from QCD. The formalism relies on the construction of an efficient quasiparticle gluon basis for Hamiltonian QCD in Coulomb gauge. The resulting rapidly convergent Fock space expansion is exploited to derive quenched low-lying glueball masses with no free parameters which are in remarkable agreement with lattice gauge theory.

  15. Lie Symmetries of Ishimori Equation

    Institute of Scientific and Technical Information of China (English)

    SONG Xu-Xia

    2013-01-01

    The Ishimori equation is one of the most important (2+1)-dimensional integrable models,which is an integrable generalization of (1+1)-dimensional classical continuous Heisenberg ferromagnetic spin equations.Based on importance of Lie symmetries in analysis of differential equations,in this paper,we derive Lie symmetries for the Ishimori equation by Hirota's direct method.

  16. Lying despite telling the truth.

    Science.gov (United States)

    Wiegmann, Alex; Samland, Jana; Waldmann, Michael R

    2016-05-01

    According to the standard definition of lying an utterance counts as a lie if the agent believes the statement to be false. Thus, according to this view it is possible that a lie states something that happens to be true. This subjective view on lying has recently been challenged by Turri and Turri (2015) who presented empirical evidence suggesting that people only consider statements as lies that are objectively false (objective view). We argue that the presented evidence is in fact consistent with the standard subjective view if conversational pragmatics is taken into account. Three experiments are presented that directly test and support the subjective view. An additional experiment backs up our pragmatic hypothesis by using the uncontroversial case of making a promise.

  17. Group discussion improves lie detection.

    Science.gov (United States)

    Klein, Nadav; Epley, Nicholas

    2015-06-16

    Groups of individuals can sometimes make more accurate judgments than the average individual could make alone. We tested whether this group advantage extends to lie detection, an exceptionally challenging judgment with accuracy rates rarely exceeding chance. In four experiments, we find that groups are consistently more accurate than individuals in distinguishing truths from lies, an effect that comes primarily from an increased ability to correctly identify when a person is lying. These experiments demonstrate that the group advantage in lie detection comes through the process of group discussion, and is not a product of aggregating individual opinions (a "wisdom-of-crowds" effect) or of altering response biases (such as reducing the "truth bias"). Interventions to improve lie detection typically focus on improving individual judgment, a costly and generally ineffective endeavor. Our findings suggest a cheap and simple synergistic approach of enabling group discussion before rendering a judgment.

  18. Discrete optimization

    CERN Document Server

    Parker, R Gary

    1988-01-01

    This book treats the fundamental issues and algorithmic strategies emerging as the core of the discipline of discrete optimization in a comprehensive and rigorous fashion. Following an introductory chapter on computational complexity, the basic algorithmic results for the two major models of polynomial algorithms are introduced--models using matroids and linear programming. Further chapters treat the major non-polynomial algorithms: branch-and-bound and cutting planes. The text concludes with a chapter on heuristic algorithms.Several appendixes are included which review the fundamental ideas o

  19. Advective-diffusive transport in microflows

    Science.gov (United States)

    Anderson, Patrick; Speetjens, Michel; Gorodetskyi, Oleksandr

    2014-11-01

    Advective-diffusive transport in microflows is studied by means of the diffusive mapping method, a recent extension of the mapping method by Gorodetskyi et al. (Phys. Fluids 24, 2012) that includes molecular diffusion. This greatly expands the application area of the mapping technique and makes the powerful concepts of eigenmode decomposition and spectral analysis of scalar transport accessible to an important class of flows: inline micromixers with diffusion. The staggered herringbone micro-mixer is adopted as a prototypical three-dimensional micro mixer. Simulations with the diffusive mapping method are in close agreement with experimental observations in literature and expose a strong impact of diffusion on the transport. Diffusion enables crossing of Lagrangian transport barriers and thus smoothens concentration gradients and accelerates homogenization. Spectral analysis of the mapping matrix reveals this already occurs on a modal level in that individual eigenmodes progressively smoothen and spread out across transport barriers with stronger diffusion. Concurrently, the corresponding eigenvalues diminish and thus fundamentally alter the mixing process by invariably causing homogenization, irrespective of the Lagrangian flow structure.

  20. Quantifying streambed advection and conduction heat fluxes

    Science.gov (United States)

    Caissie, Daniel; Luce, Charles H.

    2017-02-01

    Groundwater and accompanying heat fluxes are particularly relevant for aquatic habitats as they influence living conditions both within the river and streambed. This study focuses on the theory and the development of new equations to estimate conduction and advection heat fluxes into and out of the bed, correcting some earlier misunderstandings and adding parameterizations that extend our understanding of timing of heat fluxes. The new heat flux equations are illustrated using Catamaran Brook (New Brunswick, Canada) stream/streambed temperature data. We show important relationships between fluxes when the surface water temperature (1) follows a sinusoidal function superimposed on a steady state condition (constant deep streambed temperature) and (2) when sinusoidal variations in stream temperature at two frequencies (annual and diel) are superimposed. When the stream temperature is used as a prescribed boundary condition, the contribution of bed fluid fluxes to stream temperature occurs through the effects of conductive thermal gradients, not through direct contribution/mixing of cold/warm water. Boundary conditions can be modified, however, to account for direct contribution of cold/warm water (e.g., localized upwelling) and consequences for the conduction heat flux. Equations developed allow for prediction of conductive fluxes to the bed during summer driven by diel and annual temperature fluctuations of the stream water and good agreement was observed between analytic solutions and field data. Results from this study provide a better insight into groundwater and heat fluxes which will ultimately result in better stream temperature models and a better management of fisheries resources.

  1. Detecting true lies: police officers' ability to detect suspects' lies.

    Science.gov (United States)

    Mann, Samantha; Vrij, Aldert; Bull, Ray

    2004-02-01

    Ninety-nine police officers, not identified in previous research as belonging to groups that are superior in lie detection, attempted to detect truths and lies told by suspects during their videotaped police interviews. Accuracy rates were higher than those typically found in deception research and reached levels similar to those obtained by specialized lie detectors in previous research. Accuracy was positively correlated with perceived experience in interviewing suspects and with mentioning cues to detecting deceit that relate to a suspect's story. Accuracy was negatively correlated with popular stereotypical cues such as gaze aversion and fidgeting. As in previous research, accuracy and confidence were not significantly correlated, but the level of confidence was dependent on whether officers judged actual truths or actual lies and on the method by which confidence was measured.

  2. Lying aversion and prosocial behaviour

    CERN Document Server

    Biziou-van-Pol, Laura; Novaro, Arianna; Liberman, Andrés Occhipinti; Capraro, Valerio

    2015-01-01

    The focus of this paper is the moral conflict between lying aversion and prosociality. What does telling a white lie signal about a person's prosocial tendencies? How does believing a possibly untruthful message signal about a listener's prosocial tendencies? To answer these questions, we conducted a 2x3 experiment. In the first stage we measured altruistic tendencies using a Dictator Game and cooperative tendencies using a Prisoner's dilemma. In the second stage, we used a sender-receiver game to measure aversion to telling a Pareto white lie (i.e., a lie that helps both the liar and the listener), aversion to telling an altruistic white lie (i.e., a lie that helps the listener at the expense of the liar), and skepticism towards believing a possibly untruthful message. We found three major results: (i) both altruism and cooperation are positively correlated with aversion to telling a Pareto white lie; (ii) neither altruism nor cooperation are significantly correlated with aversion to telling an altruistic wh...

  3. Lies, Calculations and Constructions: Beyond How to Lie with Statistics

    OpenAIRE

    Best, Joel

    2005-01-01

    Darrell Huff’s How to Lie with Statistics remains the best-known, nontechnical call for critical thinking about statistics. However, drawing a distinction between statistics and lying ignores the process by which statistics are socially constructed. For instance, bad statistics often are disseminated by sincere, albeit innumerate advocates (e.g., inflated estimates for the number of anorexia deaths) or through research findings selectively highlighted to attract media coverage (e.g., a recent...

  4. Last Multipliers on Lie Algebroids

    Indian Academy of Sciences (India)

    Mircea Crasmareanu; Cristina-Elena Hreţcanu

    2009-06-01

    In this paper we extend the theory of last multipliers as solutions of the Liouville’s transport equation to Lie algebroids with their top exterior power as trivial line bundle (previously developed for vector fields and multivectors). We define the notion of exact section and the Liouville equation on Lie algebroids. The aim of the present work is to develop the theory of this extension from the tangent bundle algebroid to a general Lie algebroid (e.g. the set of sections with a prescribed last multiplier is still a Gerstenhaber subalgebra). We present some characterizations of this extension in terms of Witten and Marsden differentials.

  5. On Discrete Differential Geometry in Twistor Space

    OpenAIRE

    2011-01-01

    In this paper we introduce a discrete integrable system generalizing the discrete (real) cross-ratio system in $S^4$ to complex values of a generalized cross-ratio by considering $S^4$ as a real section of the complex Pl\\"ucker quadric, realized as the space of two-spheres in $S^4.$ We develop the geometry of the Pl\\"ucker quadric by examining the novel contact properties of two-spheres in $S^4,$ generalizing classical Lie geometry in $S^3.$ Discrete differential geometry aims to develop disc...

  6. Discrete transforms

    CERN Document Server

    Firth, Jean M

    1992-01-01

    The analysis of signals and systems using transform methods is a very important aspect of the examination of processes and problems in an increasingly wide range of applications. Whereas the initial impetus in the development of methods appropriate for handling discrete sets of data occurred mainly in an electrical engineering context (for example in the design of digital filters), the same techniques are in use in such disciplines as cardiology, optics, speech analysis and management, as well as in other branches of science and engineering. This text is aimed at a readership whose mathematical background includes some acquaintance with complex numbers, linear differen­ tial equations, matrix algebra, and series. Specifically, a familiarity with Fourier series (in trigonometric and exponential forms) is assumed, and an exposure to the concept of a continuous integral transform is desirable. Such a background can be expected, for example, on completion of the first year of a science or engineering degree cour...

  7. Gravitating fluids with Lie symmetries

    CERN Document Server

    Msomi, A M; Maharaj, S D

    2010-01-01

    We analyse the underlying nonlinear partial differential equation which arises in the study of gravitating flat fluid plates of embedding class one. Our interest in this equation lies in discussing new solutions that can be found by means of Lie point symmetries. The method utilised reduces the partial differential equation to an ordinary differential equation according to the Lie symmetry admitted. We show that a class of solutions found previously can be characterised by a particular Lie generator. Several new families of solutions are found explicitly. In particular we find the relevant ordinary differential equation for all one-dimensional optimal subgroups; in several cases the ordinary differential equation can be solved in general. We are in a position to characterise particular solutions with a linear barotropic equation of state.

  8. Historical Techniques of Lie Detection

    Directory of Open Access Journals (Sweden)

    Martina Vicianova

    2015-08-01

    Full Text Available Since time immemorial, lying has been a part of everyday life. For this reason, it has become a subject of interest in several disciplines, including psychology. The purpose of this article is to provide a general overview of the literature and thinking to date about the evolution of lie detection techniques. The first part explores ancient methods recorded circa 1000 B.C. (e.g., God’s judgment in Europe. The second part describes technical methods based on sciences such as phrenology, polygraph and graphology. This is followed by an outline of more modern-day approaches such as FACS (Facial Action Coding System, functional MRI, and Brain Fingerprinting. Finally, after the familiarization with the historical development of techniques for lie detection, we discuss the scope for new initiatives not only in the area of designing new methods, but also for the research into lie detection itself, such as its motives and regulatory issues related to deception.

  9. Predicting salt advection in groundwater from saline aquaculture ponds

    Science.gov (United States)

    Verrall, D. P.; Read, W. W.; Narayan, K. A.

    2009-01-01

    SummaryThis paper predicts saltwater advection in groundwater from leaky aquaculture ponds. A closed form solution for the potential function, stream function and velocity field is derived via the series solutions method. Numerically integrating along different streamlines gives the location (or advection front) of saltwater throughout the domain for any predefined upper time limit. Extending this process produces a function which predicts advection front location against time. The models considered in this paper are easily modified given knowledge of the required physical parameters.

  10. Designing for chaos: applications of chaotic advection at the microscale.

    Science.gov (United States)

    Stremler, Mark A; Haselton, F R; Aref, Hassan

    2004-05-15

    Chaotic advection can play an important role in efficient microfluidic mixers. We discuss a design paradigm that exploits chaotic advection and illustrate by two recent examples, namely enhancing gene expression profiling and constructing an in-line microfluidic mixing channel, how application of this paradigm has led to successful micromixers. We suggest that 'designing for chaos', that is, basing practical mixer design on chaotic advection analysis, is a promising approach to adopt in this developing field which otherwise has little to guide it and is constrained by issues of scale and manufacturability.

  11. Chaotic advection, diffusion, and reactions in open flows

    Energy Technology Data Exchange (ETDEWEB)

    Tel, Tamas [Institute for Theoretical Physics, Eoetvoes University, P.O. Box 32, H-1518 Budapest, (Hungary); Karolyi, Gyoergy [Department of Civil Engineering Mechanics, Technical University of Budapest, Mueegyetem rpk. 3, H-1521 Budapest, (Hungary); Pentek, Aron [Marine Physical Laboratory, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0238 (United States); Scheuring, Istvan [Department of Plant Taxonomy and Ecology, Research Group of Ecology and Theoretical Biology, Eoetvoes University, Ludovika ter 2, H-1083 Budapest, (Hungary); Toroczkai, Zoltan [Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States); Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0435 (United States); Grebogi, Celso [Institute for Plasma Research, University of Maryland, College Park, Maryland 20742 (United States); Kadtke, James [Marine Physical Laboratory, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0238 (United States)

    2000-03-01

    We review and generalize recent results on advection of particles in open time-periodic hydrodynamical flows. First, the problem of passive advection is considered, and its fractal and chaotic nature is pointed out. Next, we study the effect of weak molecular diffusion or randomness of the flow. Finally, we investigate the influence of passive advection on chemical or biological activity superimposed on open flows. The nondiffusive approach is shown to carry some features of a weak diffusion, due to the finiteness of the reaction range or reaction velocity. (c) 2000 American Institute of Physics.

  12. Signatures of fractal clustering of aerosols advected under gravity.

    Science.gov (United States)

    Vilela, Rafael D; Tél, Tamás; de Moura, Alessandro P S; Grebogi, Celso

    2007-06-01

    Aerosols under chaotic advection often approach a strange attractor. They move chaotically on this fractal set but, in the presence of gravity, they have a net vertical motion downwards. In practical situations, observational data may be available only at a given level, for example, at the ground level. We uncover two fractal signatures of chaotic advection of aerosols under the action of gravity. Each one enables the computation of the fractal dimension D(0) of the strange attractor governing the advection dynamics from data obtained solely at a given level. We illustrate our theoretical findings with a numerical experiment and discuss their possible relevance to meteorology.

  13. An explicit high order method for fractional advection diffusion equations

    Science.gov (United States)

    Sousa, Ercília

    2014-12-01

    We propose a high order explicit finite difference method for fractional advection diffusion equations. These equations can be obtained from the standard advection diffusion equations by replacing the second order spatial derivative by a fractional operator of order α with 1convergence of the numerical method through consistency and stability. The order of convergence varies between two and three and for advection dominated flows is close to three. Although the method is conditionally stable, the restrictions allow wide stability regions. The analysis is confirmed by numerical examples.

  14. A Toy Model for Advection Dominated Accretion Flows

    Institute of Scientific and Technical Information of China (English)

    汪定雄; 雷卫华; 肖看

    2003-01-01

    A toy disc model with advection dominated accretion on to a black hole is presented. The advection dominated accretion flows (ADAFs) are assumed to exist in the inner thick disc with rin < r < rout, and the disc is assumed to be geometrically thin for r > rout. Compared with Paczynski's toy model the thick disc is not limited to be 100% advective. It turns out that the inner radius rin depends not only on the outer radius rout but also on the ADAF parameters f and ε. The effects of the inner thick disc on the radiation efficiency and the temperature profile of the outer thin disc are discussed in details.

  15. Structure of Solvable Quadratic Lie Algebras

    Institute of Scientific and Technical Information of China (English)

    ZHU Lin-sheng

    2005-01-01

    @@ Killing form plays a key role in the theory of semisimple Lie algebras. It is natural to extend the study to Lie algebras with a nondegenerate symmetric invariant bilinear form. Such a Lie algebra is generally called a quadratic Lie algebra which occur naturally in physics[10,12,13]. Besides semisimple Lie algebras, interesting quadratic Lie algebras include the Kac-Moody algebras and the Extended Affine Lie algebras.

  16. Contribution of Advective and Non-advective Heat Fluxes to the Heat Budget of a Shallow Lagoon

    Directory of Open Access Journals (Sweden)

    Rodríguez-Rodríguez Miguel

    2005-01-01

    Full Text Available The heat budget in a shallow lagoon has been established from field measurements at a bihourly scale. Information on the main advective and non-advective heat fluxes were collected during year 2003 at Nueva lagoon (Almería, Southern Spain. Heat storage data was obtained from a thermistor chain located in the deepest part of the lagoon and meteorological information was acquired using an automatic meteorological station placed near the lagoon's shore. In addition, estimation of evaporation was inferred from climatic approaches. Inputs of heat energy were dominated by radiative fluxes, with received net radiation accounting on average for around 95% of the non-advective total gains and radiation losses accounting for around 70% of the non-advective total losses. Sensible heat transfer from/to the atmosphere constituted the second energy input (4% and output (20%, although heat losses by evaporation were also significant. Conduction of heat into the sediments was a relatively constant form of energy loss but constitutes a minor contribution on the overall heat budget. Considerable variability was evident in non-advective heat fluxes at different time scales, from diel to seasonal. In relation to advective heat fluxes, groundwater and irrigation surpluses added to the heat storage of Nueva lagoon, whereas heat advected via precipitation was negligible.

  17. Anomalous scaling of a scalar field advected by turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Kraichnan, R.H. [Robert H. Kraichnan, Inc., Santa Fe, NM (United States)

    1995-12-31

    Recent work leading to deduction of anomalous scaling exponents for the inertial range of an advected passive field from the equations of motion is reviewed. Implications for other turbulence problems are discussed.

  18. Lie bialgebras of generalized Witt type

    Institute of Scientific and Technical Information of China (English)

    SONG; Guang'ai; SU; Yucai

    2006-01-01

    In this paper, all Lie bialgebra structures on the Lie algebras of generalized Witt type are considered. It is proved that, for any Lie algebra W of generalized Witt type, all Lie bialgebras on W are the coboundary triangular Lie bialgebras. As a by-product, it is also proved that the first cohomology group H1(W, W (x) W) is trivial.

  19. An evaluation on Real Semisimple Lie Algebras

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ The theory of Lie groups and Lie algebras stem from that of continuous groups founded by Sophus Lie at the end of 19th century. From the beginning, the theory of Lie groups and Lie algebras has displayed great value in both theoretical researches and applications.

  20. Cohomology of Heisenberg Lie superalgebras

    Science.gov (United States)

    Bai, Wei; Liu, Wende

    2017-02-01

    Suppose the ground field to be algebraically closed and of characteristic different from 2 and 3. All Heisenberg Lie superalgebras consist of two super-versions of the Heisenberg Lie algebras, 𝔥2m,n and 𝔟𝔞n with m a non-negative integer and n a positive integer. The space of a "classical" Heisenberg Lie superalgebra 𝔥2m,n is the direct sum of a superspace with a non-degenerate anti-supersymmetric even bilinear form and a one-dimensional space of values of this form constituting the even center. The other super-analog of the Heisenberg Lie algebra, 𝔟𝔞n, is constructed by means of a non-degenerate anti-supersymmetric odd bilinear form with values in the one-dimensional odd center. In this paper, we study the cohomology of 𝔥2m,n and 𝔟𝔞n with coefficients in the trivial module by using the Hochschild-Serre spectral sequences relative to a suitable ideal. In the characteristic zero case, for any Heisenberg Lie superalgebra, we determine completely the Betti numbers and associative superalgebra structures for their cohomology. In the characteristic p > 3 case, we determine the associative superalgebra structure for the divided power cohomology of 𝔟𝔞n and we also make an attempt to determine the divided power cohomology of 𝔥2m,n by computing it in a low-dimensional case.

  1. Truth therapy/lie therapy.

    Science.gov (United States)

    Langs, R

    In this paper an attempt is made to conceptualize a basic dimension of various psychotherapeutic treatment modalities, especially psychoanalysis and psychoanalytically oriented psychotherapy. The central variable under consideration is the extent to which each endeavors to approach the truth within both patient and therapist as it exists dynamically in terms of their spiraling unconscious communicative interaction. That treatment modality which takes into account every possible dimension of such truths is termed truth therapy. Treatment modalities that make no attempt to arrive at these truths or that deliberately or inadvertently falsify their nature are termed lie or barrier therapies. Extensive consideration is given to truth therapy and the truth system on which it is based. The basis for the need for lie therapies is explored, and lie systems, which may arise from either patient or therapist, or both, are identified. A classification of common types of lie patients and lie therapists (and their main techniques) is offered. The implications of this delineation for our understanding of the dynamic therapies are discussed, and a number of new clinical issues arising from this perspective are addressed.

  2. Discretizing singular point sources in hyperbolic wave propagation problems

    Science.gov (United States)

    Petersson, N. Anders; O'Reilly, Ossian; Sjögreen, Björn; Bydlon, Samuel

    2016-09-01

    We develop high order accurate source discretizations for hyperbolic wave propagation problems in first order formulation that are discretized by finite difference schemes. By studying the Fourier series expansions of the source discretization and the finite difference operator, we derive sufficient conditions for achieving design accuracy in the numerical solution. Only half of the conditions in Fourier space can be satisfied through moment conditions on the source discretization, and we develop smoothness conditions for satisfying the remaining accuracy conditions. The resulting source discretization has compact support in physical space, and is spread over as many grid points as the number of moment and smoothness conditions. In numerical experiments we demonstrate high order of accuracy in the numerical solution of the 1-D advection equation (both in the interior and near a boundary), the 3-D elastic wave equation, and the 3-D linearized Euler equations.

  3. Approximation of the Lévy Feller advection dispersion process by random walk and finite difference method

    Science.gov (United States)

    Liu, Q.; Liu, F.; Turner, I.; Anh, V.

    2007-03-01

    In this paper we present a random walk model for approximating a Lévy-Feller advection-dispersion process, governed by the Lévy-Feller advection-dispersion differential equation (LFADE). We show that the random walk model converges to LFADE by use of a properly scaled transition to vanishing space and time steps. We propose an explicit finite difference approximation (EFDA) for LFADE, resulting from the Grünwald-Letnikov discretization of fractional derivatives. As a result of the interpretation of the random walk model, the stability and convergence of EFDA for LFADE in a bounded domain are discussed. Finally, some numerical examples are presented to show the application of the present technique.

  4. Finite dimensional quadratic Lie superalgebras

    CERN Document Server

    Jarvis, Peter; Yates, Luke

    2010-01-01

    We consider a special class of Z_2-graded, polynomial algebras of degree 2, which we call quadratic Lie superalgebras. Starting from the formal definition, we discuss the generalised Jacobi relations in the context of the Koszul property, and give a proof of the PBW basis theorem. We give several concrete examples of quadratic Lie superalgebras for low dimensional cases, and discuss aspects of their structure constants for the `type I' class. Based on the factorisation of the enveloping algebra, we derive the Kac module construction for typical and atypical modules, and a related direct construction of irreducible modules due to Gould. We investigate the method for one specific case, the quadratic generalisation gl_2(n/1) of the Lie superalgebra sl(n/1). We formulate the general atypicality conditions at level 1, and present an analysis of zero-and one-step atypical modules for a certain family of Kac modules.

  5. On Split Lie Triple Systems

    Indian Academy of Sciences (India)

    Antonio J Calderón Martín

    2009-04-01

    We begin the study of arbitrary split Lie triple systems by focussing on those with a coherent 0-root space. We show that any such triple systems with a symmetric root system is of the form $T=\\mathcal{U}+\\sum_j I_j$ with $\\mathcal{U}$ a subspace of the 0-root space $T_0$ and any $I_j$ a well described ideal of , satisfying $[I_j,T,I_k]=0$ if $j≠ k$. Under certain conditions, it is shown that is the direct sum of the family of its minimal ideals, each one being a simple split Lie triple system, and the simplicity of is characterized. The key tool in this job is the notion of connection of roots in the framework of split Lie triple systems.

  6. Loop Virasoro Lie conformal algebra

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Henan, E-mail: wuhenanby@163.com; Chen, Qiufan; Yue, Xiaoqing [Department of Mathematics, Tongji University, Shanghai 200092 (China)

    2014-01-15

    The Lie conformal algebra of loop Virasoro algebra, denoted by CW, is introduced in this paper. Explicitly, CW is a Lie conformal algebra with C[∂]-basis (L{sub i} | i∈Z) and λ-brackets [L{sub i} {sub λ} L{sub j}] = (−∂−2λ)L{sub i+j}. Then conformal derivations of CW are determined. Finally, rank one conformal modules and Z-graded free intermediate series modules over CW are classified.

  7. Energetics of lateral eddy diffusion/advection:Part III. Energetics of horizontal and isopycnal diffusion/advection

    Institute of Scientific and Technical Information of China (English)

    HUANG Rui Xin

    2014-01-01

    Gravitational Potential Energy (GPE) change due to horizontal/isopycnal eddy diffusion and advection is examined. Horizontal/isopycnal eddy diffusion is conceptually separated into two steps:stirring and sub-scale diffusion. GPE changes associated with these two steps are analyzed. In addition, GPE changes due to stirring and subscale diffusion associated with horizontal/isopycnal advection in the Eulerian coordinates are analyzed. These formulae are applied to the SODA data for the world oceans. Our analysis indicates that horizontal/isopycnal advection in Eulerian coordinates can introduce large artificial diffusion in the model. It is shown that GPE source/sink in isopycnal coordinates is closely linked to physical property distribution, such as temperature, salinity and velocity. In comparison with z-coordinates, GPE source/sink due to stir-ring/cabbeling associated with isopycnal diffusion/advection is much smaller. Although isopycnal coordi-nates may be a better choice in terms of handling lateral diffusion, advection terms in the traditional Eule-rian coordinates can produce artificial source of GPE due to cabbeling associated with advection. Reducing such numerical errors remains a grand challenge.

  8. Isomorphism of Intransitive Linear Lie Equations

    Directory of Open Access Journals (Sweden)

    Jose Miguel Martins Veloso

    2009-11-01

    Full Text Available We show that formal isomorphism of intransitive linear Lie equations along transversal to the orbits can be extended to neighborhoods of these transversal. In analytic cases, the word formal is dropped from theorems. Also, we associate an intransitive Lie algebra with each intransitive linear Lie equation, and from the intransitive Lie algebra we recover the linear Lie equation, unless of formal isomorphism. The intransitive Lie algebra gives the structure functions introduced by É. Cartan.

  9. Discretization of topological spaces

    OpenAIRE

    Amini, Massoud; Golestani, Nasser

    2014-01-01

    There are several compactification procedures in topology, but there is only one standard discretization, namely, replacing the original topology with the discrete topology. We give a notion of discretization which is dual (in categorical sense) to compactification and give examples of discretizations. Especially, a discretization functor from the category of $\\alpha$-scattered Stonean spaces to the category of discrete spaces is constructed which is the converse of the Stone-\\v{C}ech compact...

  10. A Fully Discrete Galerkin Method for a Nonlinear Space-Fractional Diffusion Equation

    Directory of Open Access Journals (Sweden)

    Yunying Zheng

    2011-01-01

    Full Text Available The spatial transport process in fractal media is generally anomalous. The space-fractional advection-diffusion equation can be used to characterize such a process. In this paper, a fully discrete scheme is given for a type of nonlinear space-fractional anomalous advection-diffusion equation. In the spatial direction, we use the finite element method, and in the temporal direction, we use the modified Crank-Nicolson approximation. Here the fractional derivative indicates the Caputo derivative. The error estimate for the fully discrete scheme is derived. And the numerical examples are also included which are in line with the theoretical analysis.

  11. Cartan Connections and Lie Algebroids

    Directory of Open Access Journals (Sweden)

    Michael Crampin

    2009-06-01

    Full Text Available This paper is a study of the relationship between two constructions associated with Cartan geometries, both of which involve Lie algebroids: the Cartan algebroid, due to [Blaom A.D., Trans. Amer. Math. Soc. 358 (2006, 3651–3671], and tractor calculus [Cap A., Gover A.R., Trans. Amer. Math. Soc. 354 (2001, 1511–1548].

  12. Cartan Connections and Lie Algebroids

    CERN Document Server

    Crampin, Michael

    2009-01-01

    This paper is a study of the relationship between two constructions associated with Cartan geometries, both of which involve Lie algebroids: the Cartan algebroid, due to [Blaom A.D., Trans. Amer. Math. Soc. 358 (2006), 3651-3671], and tractor calculus [Cap A., Gover A.R., Trans. Amer. Math. Soc. 354 (2001), 1511-1548].

  13. String Topology for Lie Groups

    DEFF Research Database (Denmark)

    A. Hepworth, Richard

    2010-01-01

    In 1999 Chas and Sullivan showed that the homology of the free loop space of an oriented manifold admits the structure of a Batalin-Vilkovisky algebra. In this paper we give a direct description of this Batalin-Vilkovisky algebra in the case that the manifold is a compact Lie group G. Our answer ...

  14. Low-Dissipation Advection Schemes Designed for Large Eddy Simulations of Hypersonic Propulsion Systems

    Science.gov (United States)

    White, Jeffrey A.; Baurle, Robert A.; Fisher, Travis C.; Quinlan, Jesse R.; Black, William S.

    2012-01-01

    The 2nd-order upwind inviscid flux scheme implemented in the multi-block, structured grid, cell centered, finite volume, high-speed reacting flow code VULCAN has been modified to reduce numerical dissipation. This modification was motivated by the desire to improve the codes ability to perform large eddy simulations. The reduction in dissipation was accomplished through a hybridization of non-dissipative and dissipative discontinuity-capturing advection schemes that reduces numerical dissipation while maintaining the ability to capture shocks. A methodology for constructing hybrid-advection schemes that blends nondissipative fluxes consisting of linear combinations of divergence and product rule forms discretized using 4th-order symmetric operators, with dissipative, 3rd or 4th-order reconstruction based upwind flux schemes was developed and implemented. A series of benchmark problems with increasing spatial and fluid dynamical complexity were utilized to examine the ability of the candidate schemes to resolve and propagate structures typical of turbulent flow, their discontinuity capturing capability and their robustness. A realistic geometry typical of a high-speed propulsion system flowpath was computed using the most promising of the examined schemes and was compared with available experimental data to demonstrate simulation fidelity.

  15. Discrete Curvatures and Discrete Minimal Surfaces

    KAUST Repository

    Sun, Xiang

    2012-06-01

    This thesis presents an overview of some approaches to compute Gaussian and mean curvature on discrete surfaces and discusses discrete minimal surfaces. The variety of applications of differential geometry in visualization and shape design leads to great interest in studying discrete surfaces. With the rich smooth surface theory in hand, one would hope that this elegant theory can still be applied to the discrete counter part. Such a generalization, however, is not always successful. While discrete surfaces have the advantage of being finite dimensional, thus easier to treat, their geometric properties such as curvatures are not well defined in the classical sense. Furthermore, the powerful calculus tool can hardly be applied. The methods in this thesis, including angular defect formula, cotangent formula, parallel meshes, relative geometry etc. are approaches based on offset meshes or generalized offset meshes. As an important application, we discuss discrete minimal surfaces and discrete Koenigs meshes.

  16. Anomalous Scaling in the Anisotropic Sectors of the Kriachnan Model of Passive Scalar Advection

    CERN Document Server

    Lvov, A I; Procaccia, I; L'vov, Itai Arad Victor S.; Podivilov, Evgenii; Procaccia, Itamar

    1999-01-01

    Kraichnan's model of passive scalar advection is studied as a case model for understanding the anomalous scaling in the anisotropic sectors. We show here that the solutions of the Kraichnan equation for the $n$ order correlations foliate into sectors that are classified by the irreducible representations of the SO(d) group. We find a discrete spectrum of universal anomalous exponents in every sector. Generically the correlations and structure functions appear as sums over all the contributions, with non-universal amplitudes which are determined by the anisotropic boundary conditions. The isotropic sector is always characterized by the smallest exponent, and therefore for sufficiently small scales local isotropy is always restored. The calculation of the anomalous exponents is done in two complementary ways. In the first they are obtained from the analysis of correlations of gradient fields. The corresponding theory involves the control of logarithmic divergences which translate into anomalous scaling with the...

  17. Modeling size segregation of granular materials: the roles of segregation, advection and diffusion

    CERN Document Server

    Fan, Yi; Umbanhowar, Paul B; Ottino, Julio M; Lueptow, Richard M

    2014-01-01

    Predicting segregation of granular materials composed of different-sized particles is a challenging problem. In this paper, we develop and implement a theoretical model that captures the interplay between advection, segregation, and diffusion in size bidisperse granular materials. The fluxes associated with these three driving factors depend on the underlying kinematics, whose characteristics play key roles in determining particle segregation configurations. Unlike previous models for segregation, our model uses parameters based on kinematic measures from discrete element method simulations instead of arbitrarily adjustable fitting parameters, and it achieves excellent quantitative agreement with both experimental and simulation results when applied to quasi-two-dimensional bounded heaps. The model yields two dimensionless control parameters, both of which are only functions of physically control parameters (feed rate, particle sizes, and system size) and kinematic parameters (diffusion coefficient, flowing l...

  18. A self-organizing Lagrangian particle method for adaptive-resolution advection-diffusion simulations

    Science.gov (United States)

    Reboux, Sylvain; Schrader, Birte; Sbalzarini, Ivo F.

    2012-05-01

    We present a novel adaptive-resolution particle method for continuous parabolic problems. In this method, particles self-organize in order to adapt to local resolution requirements. This is achieved by pseudo forces that are designed so as to guarantee that the solution is always well sampled and that no holes or clusters develop in the particle distribution. The particle sizes are locally adapted to the length scale of the solution. Differential operators are consistently evaluated on the evolving set of irregularly distributed particles of varying sizes using discretization-corrected operators. The method does not rely on any global transforms or mapping functions. After presenting the method and its error analysis, we demonstrate its capabilities and limitations on a set of two- and three-dimensional benchmark problems. These include advection-diffusion, the Burgers equation, the Buckley-Leverett five-spot problem, and curvature-driven level-set surface refinement.

  19. On enforcing maximum principles and achieving element-wise species balance for advection-diffusion-reaction equations under the finite element method

    Science.gov (United States)

    Mudunuru, M. K.; Nakshatrala, K. B.

    2016-01-01

    We present a robust computational framework for advective-diffusive-reactive systems that satisfies maximum principles, the non-negative constraint, and element-wise species balance property. The proposed methodology is valid on general computational grids, can handle heterogeneous anisotropic media, and provides accurate numerical solutions even for very high Péclet numbers. The significant contribution of this paper is to incorporate advection (which makes the spatial part of the differential operator non-self-adjoint) into the non-negative computational framework, and overcome numerical challenges associated with advection. We employ low-order mixed finite element formulations based on least-squares formalism, and enforce explicit constraints on the discrete problem to meet the desired properties. The resulting constrained discrete problem belongs to convex quadratic programming for which a unique solution exists. Maximum principles and the non-negative constraint give rise to bound constraints while element-wise species balance gives rise to equality constraints. The resulting convex quadratic programming problems are solved using an interior-point algorithm. Several numerical results pertaining to advection-dominated problems are presented to illustrate the robustness, convergence, and the overall performance of the proposed computational framework.

  20. Helical turbulent Prandtl number in the A model of passive vector advection

    Science.gov (United States)

    Hnatič, M.; Zalom, P.

    2016-11-01

    Using the field theoretic renormalization group technique in the two-loop approximation, turbulent Prandtl numbers are obtained in the general A model of passive vector advected by fully developed turbulent velocity field with violation of spatial parity introduced via the continuous parameter ρ ranging from ρ =0 (no violation of spatial parity) to |ρ |=1 (maximum violation of spatial parity). Values of A represent a continuously adjustable parameter which governs the interaction structure of the model. In nonhelical environments, we demonstrate that A is restricted to the interval -1.723 ≤A ≤2.800 (rounded to 3 decimal places) in the two-loop order of the field theoretic model. However, when ρ >0.749 (rounded to 3 decimal places), the restrictions may be removed, which means that presence of helicity exerts a stabilizing effect onto the possible stationary regimes of the system. Furthermore, three physically important cases A ∈{-1 ,0 ,1 } are shown to lie deep within the allowed interval of A for all values of ρ . For the model of the linearized Navier-Stokes equations (A =-1 ) up to date unknown helical values of the turbulent Prandtl number have been shown to equal 1 regardless of parity violation. Furthermore, we have shown that interaction parameter A exerts strong influence on advection-diffusion processes in turbulent environments with broken spatial parity. By varying A continuously, we explain high stability of the kinematic MHD model (A =1 ) against helical effects as a result of its proximity to the A =0.912 (rounded to 3 decimal places) case where helical effects are completely suppressed. Contrary, for the physically important A =0 model, we show that it lies deep within the interval of models where helical effects cause the turbulent Prandtl number to decrease with |ρ | . We thus identify internal structure of interactions given by the parameter A , and not the vector character of the admixture itself being the dominant factor influencing

  1. Helical turbulent Prandtl number in the A model of passive vector advection.

    Science.gov (United States)

    Hnatič, M; Zalom, P

    2016-11-01

    Using the field theoretic renormalization group technique in the two-loop approximation, turbulent Prandtl numbers are obtained in the general A model of passive vector advected by fully developed turbulent velocity field with violation of spatial parity introduced via the continuous parameter ρ ranging from ρ=0 (no violation of spatial parity) to |ρ|=1 (maximum violation of spatial parity). Values of A represent a continuously adjustable parameter which governs the interaction structure of the model. In nonhelical environments, we demonstrate that A is restricted to the interval -1.723≤A≤2.800 (rounded to 3 decimal places) in the two-loop order of the field theoretic model. However, when ρ>0.749 (rounded to 3 decimal places), the restrictions may be removed, which means that presence of helicity exerts a stabilizing effect onto the possible stationary regimes of the system. Furthermore, three physically important cases A∈{-1,0,1} are shown to lie deep within the allowed interval of A for all values of ρ. For the model of the linearized Navier-Stokes equations (A=-1) up to date unknown helical values of the turbulent Prandtl number have been shown to equal 1 regardless of parity violation. Furthermore, we have shown that interaction parameter A exerts strong influence on advection-diffusion processes in turbulent environments with broken spatial parity. By varying A continuously, we explain high stability of the kinematic MHD model (A=1) against helical effects as a result of its proximity to the A=0.912 (rounded to 3 decimal places) case where helical effects are completely suppressed. Contrary, for the physically important A=0 model, we show that it lies deep within the interval of models where helical effects cause the turbulent Prandtl number to decrease with |ρ|. We thus identify internal structure of interactions given by the parameter A, and not the vector character of the admixture itself being the dominant factor influencing diffusion-advection

  2. Discrete auroras and magnetotail processes.

    Science.gov (United States)

    Lyons, L. R.

    Important information about magnetospheric phenomena associated with auroras and substorms can be inferred from low-altitude auroral observations. Satellite observations have shown that discrete auroral arcs lie within a boundary plasma sheet (BPS) region that is outside the central plasma sheet (CPS). The observations imply that arcs are generated along BPS field lines by magnetospheric processes that form large, perpendicular electric field structures. The BPS and the arc generation processes apparently lie along field lines that are in the vicinity of the boundary between open and closed field lines and cross the tail (or magnetopause) current sheet. Ground-based observations show that the first indication of a substorm onset is the brightening of a quiet, discrete arc. This suggests that substorms are initiated along the BPS field lines associated with arc generation, and not within the CPS. Finally, auroral observations have shown that the area of open, polar-cap field lines varies considerably during periods of geomagnetic activity. Expansion of the polar cap has the potential for releasing trapped plasma sheet particles along freshly open field lines. The resulting evacuation of field lines has the potential for being an important loss process for the plasma sheet and for being a source of tailward flows and energetic particle bursts in the tail.

  3. Coupling of Active Motion and Advection Shapes Intracellular Cargo Transport

    CERN Document Server

    Trong, P Khuc; Goldstein, R E; 10.1103/PhysRevLett.109.028104

    2012-01-01

    Intracellular cargo transport can arise from passive diffusion, active motor-driven transport along cytoskeletal filament networks, and passive advection by fluid flows entrained by such motor/cargo motion. Active and advective transport are thus intrinsically coupled as related, yet different representations of the same underlying network structure. A reaction-advection-diffusion system is used here to show that this coupling affects the transport and localization of a passive tracer in a confined geometry. For sufficiently low diffusion, cargo localization to a target zone is optimized either by low reaction kinetics and decoupling of bound and unbound states, or by a mostly disordered cytoskeletal network with only weak directional bias. These generic results may help to rationalize subtle features of cytoskeletal networks, for example as observed for microtubules in fly oocytes.

  4. Concentration polarization, surface currents, and bulk advection in a microchannel

    CERN Document Server

    Nielsen, Christoffer P

    2014-01-01

    We present a comprehensive analysis of salt transport and overlimiting currents in a microchannel during concentration polarization. We have carried out full numerical simulations of the coupled Poisson-Nernst-Planck-Stokes problem governing the transport and rationalized the behaviour of the system. A remarkable outcome of the investigations is the discovery of strong couplings between bulk advection and the surface current; without a surface current, bulk advection is strongly suppressed. The numerical simulations are supplemented by analytical models valid in the long channel limit as well as in the limit of negligible surface charge. By including the effects of diffusion and advection in the diffuse part of the electric double layers, we extend a recently published analytical model of overlimiting current due to surface conduction.

  5. Semiclassical states on Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Tsobanjan, Artur, E-mail: artur.tsobanjan@gmail.com [King’s College, 133 North River Street, Kingston, Pennsylvania 18702 (United States)

    2015-03-15

    The effective technique for analyzing representation-independent features of quantum systems based on the semiclassical approximation (developed elsewhere) has been successfully used in the context of the canonical (Weyl) algebra of the basic quantum observables. Here, we perform the important step of extending this effective technique to the quantization of a more general class of finite-dimensional Lie algebras. The case of a Lie algebra with a single central element (the Casimir element) is treated in detail by considering semiclassical states on the corresponding universal enveloping algebra. Restriction to an irreducible representation is performed by “effectively” fixing the Casimir condition, following the methods previously used for constrained quantum systems. We explicitly determine the conditions under which this restriction can be consistently performed alongside the semiclassical truncation.

  6. Symmetry via Lie algebra cohomology

    CERN Document Server

    Eastwood, Michael

    2010-01-01

    The Killing operator on a Riemannian manifold is a linear differential operator on vector fields whose kernel provides the infinitesimal Riemannian symmetries. The Killing operator is best understood in terms of its prolongation, which entails some simple tensor identities. These simple identities can be viewed as arising from the identification of certain Lie algebra cohomologies. The point is that this case provides a model for more complicated operators similarly concerned with symmetry.

  7. Noether conserved quantities and Lie point symmetries of difference Lagrange-Maxwell equations and lattices

    Institute of Scientific and Technical Information of China (English)

    Fu Jing-Li; Nie Ning-Ming; Huang Jian-Fei; Jiménez Salvador; Tang Yi-Fa; Vázquez Luis; Zhao Wei-Jia

    2009-01-01

    This paper presents a method to find Noether-type conserved quantities and Lie point symmetries for discrete mechanico-electrical dynamical systems, which leave invariant the set of solutions of the corresponding difference scheme.This approach makes it possible to devise techniques for solving the Lagrange-Maxwell equations in differences which correspond to mechanico-electrical systems, by adapting existing differential equations. In particular, it obtains a new systematic method to determine both the one-parameter Lie groups and the discrete Noether conserved quantities of Lie point symmetries for mechanico-electrical systems. As an application, it obtains the Lie point symmetries and the conserved quantities for the difference equation of a model that represents a capacitor microphone.

  8. Can Lies Be Detected Unconsciously?

    Directory of Open Access Journals (Sweden)

    David eShanks

    2015-08-01

    Full Text Available People are typically poor at telling apart truthful and deceptive statements. Based on the Unconscious Thought Theory, it has been suggested that poor lie detection arises from the intrinsic limitations of conscious thinking and can be improved by facilitating the contribution of unconscious thought. In support of this hypothesis, Reinhard, Greifeneder, and Scharmach (2013 observed improved lie detection among participants engaging in unconscious thought. The present study aimed to replicate this unconscious thought advantage using a similar experimental procedure but with an important improvement in a key control condition. Specifically, participants judged the truthfulness of 8 video recordings in three thinking modes: immediately after watching them or after a period of unconscious or conscious deliberation. Results from two experiments (combined N = 226 failed to reveal a significant difference in lie detection accuracy between the thinking modes, even after efforts were made to facilitate the occurrence of an unconscious thought advantage in Experiment 2. The results imply that the unconscious thought advantage in deception detection is not a robust phenomenon.

  9. Why Canonical Disks Cannot Produce Advection Dominated Flows

    CERN Document Server

    Molteni, D; Valenza, M A

    2001-01-01

    Using simple arguments we show that the canonical thin keplerian accretion disks cannot smoothly match any plain advection dominated flow (ADAF) model. By 'plain' ADAF model we mean the ones with zero cooling. The existence of sonic points in exact solutions is critical and imposes constraints that cannot be surpassed adopting 'reasonable' physical conditions at the hypothetical match point. Only the occurrence of new critical physical phenomena may produce a transition. We propose that exact advection models are a class of solutions which don't necessarily involve the standard thin cool disks and suggest a different scenario in which good ADAF solutions could eventually occur.

  10. Particle-like structure of Lie algebras

    Science.gov (United States)

    Vinogradov, A. M.

    2017-07-01

    If a Lie algebra structure 𝔤 on a vector space is the sum of a family of mutually compatible Lie algebra structures 𝔤i's, we say that 𝔤 is simply assembled from the 𝔤i's. Repeating this procedure with a number of Lie algebras, themselves simply assembled from the 𝔤i's, one obtains a Lie algebra assembled in two steps from 𝔤i's, and so on. We describe the process of modular disassembling of a Lie algebra into a unimodular and a non-unimodular part. We then study two inverse questions: which Lie algebras can be assembled from a given family of Lie algebras, and from which Lie algebras can a given Lie algebra be assembled. We develop some basic assembling and disassembling techniques that constitute the elements of a new approach to the general theory of Lie algebras. The main result of our theory is that any finite-dimensional Lie algebra over an algebraically closed field of characteristic zero or over R can be assembled in a finite number of steps from two elementary constituents, which we call dyons and triadons. Up to an abelian summand, a dyon is a Lie algebra structure isomorphic to the non-abelian 2-dimensional Lie algebra, while a triadon is isomorphic to the 3-dimensional Heisenberg Lie algebra. As an example, we describe constructions of classical Lie algebras from triadons.

  11. An advective mechanism for deep chlorophyll maxima formation in southern Drake Passage

    Science.gov (United States)

    Erickson, Zachary K.; Thompson, Andrew F.; Cassar, Nicolas; Sprintall, Janet; Mazloff, Matthew R.

    2016-10-01

    We observe surface and subsurface fluorescence-derived chlorophyll maxima in southern Drake Passage during austral summer. Backscatter measurements indicate that the deep chlorophyll maxima (DCMs) are also deep biomass maxima, and euphotic depth estimates show that they lie below the euphotic layer. Subsurface, offshore and near-surface, onshore features lie along the same isopycnal, suggesting advective generation of DCMs. Temperature measurements indicate a warming of surface waters throughout austral summer, capping the winter water (WW) layer and increasing off-shelf stratification in this isopycnal layer. The outcrop position of the WW isopycnal layer shifts onshore, into a surface phytoplankton bloom. A lateral potential vorticity (PV) gradient develops, such that a down-gradient PV flux is consistent with offshore, along-isopycnal tracer transport. Model results are consistent with this mechanism. Subduction of chlorophyll and biomass along isopycnals represents a biological term not observed by surface satellite measurements which may contribute significantly to the strength of the biological pump in this region.

  12. Filiform Lie algebras of order 3

    Science.gov (United States)

    Navarro, R. M.

    2014-04-01

    The aim of this work is to generalize a very important type of Lie algebras and superalgebras, i.e., filiform Lie (super)algebras, into the theory of Lie algebras of order F. Thus, the concept of filiform Lie algebras of order F is obtained. In particular, for F = 3 it has been proved that by using infinitesimal deformations of the associated model elementary Lie algebra it can be obtained families of filiform elementary lie algebras of order 3, analogously as that occurs into the theory of Lie algebras [M. Vergne, "Cohomologie des algèbres de Lie nilpotentes. Application à l'étude de la variété des algèbres de Lie nilpotentes," Bull. Soc. Math. France 98, 81-116 (1970)]. Also we give the dimension, using an adaptation of the {sl}(2,{C})-module Method, and a basis of such infinitesimal deformations in some generic cases.

  13. A remapped particle-mesh semi-Lagrangian advection scheme

    NARCIS (Netherlands)

    Cotter, C.J.; Frank, J.E.; Reich, S.

    2007-01-01

    We describe the remapped particle-mesh advection method, a new mass-conserving method for solving the density equation which is suitable for combining with semi-Lagrangian methods for compressible flow applied to numerical weather prediction. In addition to the conservation property, the remapped pa

  14. Advective - dispersive contaminant transport towards a pumping well

    NARCIS (Netherlands)

    Kooten, van J.J.A.

    1996-01-01


    In this thesis we describe an analytical approximation method for predicting the advective- dispersive transport of a contaminant towards a pumping well. The groundwater flow is assumed to be stationary and essentially horizontal. Due to dispersion contaminant transport is a stochastic pr

  15. Simulating magnetised plasma with the versatile advection code

    NARCIS (Netherlands)

    Keppens, R.; Toth, G.; Palma, J. M. L.; Dongarra, J.; Hernandez, V.

    1999-01-01

    Matter in the universe mainly consists of plasma. The dynamics of plasmas is controlled by magnetic fields. To simulate the evolution of magnetised plasma, we solve the equations of magnetohydrodynamics using the Versatile Advection Code (VAC). To demonstrate the versatility of VAC, we present calcu

  16. Theory of advection-driven long range biotic transport

    Science.gov (United States)

    We propose a simple mechanistic model to examine the effects of advective flow on the spread of fungal diseases spread by wind-blown spores. The model is defined by a set of two coupled non-linear partial differential equations for spore densities. One equation describes the long-distance advectiv...

  17. Simulating magnetised plasma with the versatile advection code

    NARCIS (Netherlands)

    Keppens, R.; Toth, G.; Palma, J. M. L.; Dongarra, J.; Hernandez, V.

    1999-01-01

    Matter in the universe mainly consists of plasma. The dynamics of plasmas is controlled by magnetic fields. To simulate the evolution of magnetised plasma, we solve the equations of magnetohydrodynamics using the Versatile Advection Code (VAC). To demonstrate the versatility of VAC, we present

  18. Spinor Lie derivatives and Fermion stress-energies

    CERN Document Server

    Helfer, Adam D

    2016-01-01

    Stress-energies for Fermi fields are derived from the principle of general covariance. This is done by developing a notion of Lie derivatives of spinors along arbitrary vector fields. A substantial theory of such derivatives was first introduced by Kosmann; here I show how an apparent conflict in the literature on this is due to a difference in the definitions of spinors, and that tracking the Lie derivative of the Infeld-van der Waerden symbol, as well as the spinor fields under consideration, gives a fuller picture of the geometry and leads to the Fermion stress-energy. The differences in the definitions of spinors do not affect the results here, but could matter in certain quantum-gravity programs and for spinor transformations under discrete symmetries.

  19. Random Lie group actions on compact manifolds: a perturbative analysis

    CERN Document Server

    Sadel, Christian

    2008-01-01

    A random Lie group action on a compact manifold generates a discrete time Markov process. The main object of this paper is the evaluation of associated Birkhoff sums in a regime of weak, but sufficiently effective coupling of the randomness. This effectiveness is expressed in terms of random Lie algebra elements and replaces the transience or Furstenberg's irreducibility hypothesis in related problems. The Birkhoff sum of any given smooth function then turns out to be equal to its integral w.r.t. a unique smooth measure on the manifold up to errors of the order of the coupling constant. Applications to the theory of products of random matrices and a model of a disordered quantum wire are presented.

  20. Transformation groups and Lie algebras

    CERN Document Server

    Ibragimov, Nail H

    2013-01-01

    This book is based on the extensive experience of teaching for mathematics, physics and engineering students in Russia, USA, South Africa and Sweden. The author provides students and teachers with an easy to follow textbook spanning a variety of topics. The methods of local Lie groups discussed in the book provide universal and effective method for solving nonlinear differential equations analytically. Introduction to approximate transformation groups also contained in the book helps to develop skills in constructing approximate solutions for differential equations with a small parameter.

  1. On discrete cosine transform

    CERN Document Server

    Zhou, Jianqin

    2011-01-01

    The discrete cosine transform (DCT), introduced by Ahmed, Natarajan and Rao, has been used in many applications of digital signal processing, data compression and information hiding. There are four types of the discrete cosine transform. In simulating the discrete cosine transform, we propose a generalized discrete cosine transform with three parameters, and prove its orthogonality for some new cases. A new type of discrete cosine transform is proposed and its orthogonality is proved. Finally, we propose a generalized discrete W transform with three parameters, and prove its orthogonality for some new cases.

  2. Mimetic discretization methods

    CERN Document Server

    Castillo, Jose E

    2013-01-01

    To help solve physical and engineering problems, mimetic or compatible algebraic discretization methods employ discrete constructs to mimic the continuous identities and theorems found in vector calculus. Mimetic Discretization Methods focuses on the recent mimetic discretization method co-developed by the first author. Based on the Castillo-Grone operators, this simple mimetic discretization method is invariably valid for spatial dimensions no greater than three. The book also presents a numerical method for obtaining corresponding discrete operators that mimic the continuum differential and

  3. Bound-Preserving Discontinuous Galerkin Methods for Conservative Phase Space Advection in Curvilinear Coordinates

    CERN Document Server

    Endeve, Eirik; Xing, Yulong; Mezzacappa, Anthony

    2014-01-01

    We extend the positivity-preserving method of Zhang & Shu (2010, JCP, 229, 3091-3120) to simulate the advection of neutral particles in phase space using curvilinear coordinates. The ability to utilize these coordinates is important for non-equilibrium transport problems in general relativity and also in science and engineering applications with specific geometries. The method achieves high-order accuracy using Discontinuous Galerkin (DG) discretization of phase space and strong stability-preserving, Runge-Kutta (SSP-RK) time integration. Special care in taken to ensure that the method preserves strict bounds for the phase space distribution function $f$; i.e., $f\\in[0,1]$. The combination of suitable CFL conditions and the use of the high-order limiter proposed in Zhang & Shu (2010) is sufficient to ensure positivity of the distribution function. However, to ensure that the distribution function satisfies the upper bound, the discretization must, in addition, preserve the divergence-free property of ...

  4. Discrete mathematics, discrete physics and numerical methods

    Directory of Open Access Journals (Sweden)

    Felice Iavernaro

    2007-12-01

    Full Text Available Discrete mathematics has been neglected for a long time. It has been put in the shade by the striking success of continuous mathematics in the last two centuries, mainly because continuous models in physics proved very reliable, but also because of the greater difficulty in dealing with it. This perspective has been rapidly changing in the last years owing to the needs of the numerical analysis and, more recently, of the so called discrete physics. In this paper, starting from some sentences of Fichera about discrete and continuous world, we shall present some considerations about discrete phenomena which arise when designing numerical methods or discrete models for some classical physical problems.

  5. Nonlinear analysis of flexible plates lying on elastic foundation

    Directory of Open Access Journals (Sweden)

    Trushin Sergey

    2017-01-01

    Full Text Available This article describes numerical procedures for analysis of flexible rectangular plates lying on elastic foundation. Computing models are based on the theory of plates with account of transverse shear deformations. The finite difference energy method of discretization is used for reducing the initial continuum problem to finite dimensional problem. Solution procedures for nonlinear problem are based on Newton-Raphson method. This theory of plates and numerical methods have been used for investigation of nonlinear behavior of flexible plates on elastic foundation with different properties.

  6. Energetics of lateral eddy diffusion/advection:Part IV. Energetics of diffusion/advection in sigma coordinates and other coordinates

    Institute of Scientific and Technical Information of China (English)

    HUANG Rui Xin

    2014-01-01

    Gravitational potential energy (GPE) source and sink due to stirring and cabbeling associated with sigma dif-fusion/advection is analyzed. It is shown that GPE source and sink is too big, and they are not closely linked to physical property distribution, such as temperature, salinity and velocity. Although the most frequently quoted advantage of sigma coordinate models are their capability of dealing with topography;the exces-sive amount of GPE source and sink due to stirring and cabbeling associated with sigma diffusion/advec-tion diagnosed from our analysis raises a very serious question whether the way lateral diffusion/advection simulated in the sigma coordinates model is physically acceptable. GPE source and sink in three coordinates is dramatically different in their magnitude and patterns. Overall, in terms of simulating lateral eddy diffu-sion and advection isopycnal coordinates is the best choice and sigma coordinates is the worst. The physical reason of the excessive GPE source and sink in sigma coordinates is further explored in details. However, even in the isopycnal coordinates, simulation based on the Eulerian coordinates can be contaminated by the numerical errors associated with the advection terms.

  7. The applications of a higher-dimensional Lie algebra and its decomposed subalgebras.

    Science.gov (United States)

    Yu, Zhang; Zhang, Yufeng

    2009-01-15

    With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 x 6 matrix Lie algebra smu(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra smu(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras smu(6) and E is used to directly construct integrable couplings.

  8. Discrete Wigner function dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A B; Munoz, C [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, 44410, Guadalajara, Jalisco (Mexico)

    2005-12-01

    We study the evolution of the discrete Wigner function for prime and the power of prime dimensions using the discrete version of the star-product operation. Exact and semiclassical dynamics in the limit of large dimensions are considered.

  9. DERIVATIONS AND EXTENSIONS OF LIE COLOR ALGEBRA

    Institute of Scientific and Technical Information of China (English)

    Zhang Qingcheng; Zhang Yongzheng

    2008-01-01

    In this article, the authors obtain some results concerning derivations of fi-nitely generated Lie color algebras and discuss the relation between skew derivation space SkDer(L) and central extension H2(L, F) on some Lie color algebras. Meanwhile, they generalize the notion of double extension to quadratic Lie color algebras, a sufficient con-dition for a quadratic Lie color algebra to be a double extension and further properties are given.

  10. Discrete Noether Currents

    CERN Document Server

    Seidl, Gerhart

    2014-01-01

    We present a simple generalization of Noether's theorem for discrete symmetries in relativistic continuum field theories. We calculate explicitly the conserved current for several discrete spacetime and internal symmetries. In addition, we formulate an analogue of the Ward-Takahashi identity for the Noether current associated with a discrete symmetry.

  11. Infinite-dimensional Hamiltonian Lie superalgebras

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The natural filtration of the infinite-dimensional Hamiltonian Lie superalgebra over a field of positive characteristic is proved to be invariant under automorphisms by characterizing ad-nilpotent elements.We are thereby able to obtain an intrinsic characterization of the Hamiltonian Lie superalgebra and establish a property of the automorphisms of the Lie superalgebra.

  12. SOME RESULTS OF MODULAR LIE SUPERALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the present article, the authors give some properties on subinvariant subalgebras of modular Lie superalgebras and obtain the derivation tower theorem of modular Lie superalgebras, which is analogous to the automorphism tower theorem of finite groups.Moreover, they announce and prove some results of modular complete Lie superalgebras.

  13. Emergence of Lying in Very Young Children

    Science.gov (United States)

    Evans, Angela D.; Lee, Kang

    2013-01-01

    Lying is a pervasive human behavior. Evidence to date suggests that from the age of 42 months onward, children become increasingly capable of telling lies in various social situations. However, there is limited experimental evidence regarding whether very young children will tell lies spontaneously. The present study investigated the emergence of…

  14. A Kind of Braided-Lie Structures

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ We introduce a family of braidedLie algebras.They are Lie algebras in the unifying YetterDrinfeldLong module categoryJJMQQ where J and Q are Hopf algebras.We study their structure and the braidedLie structure of an algebra A in JJM QQ.

  15. Probability on real Lie algebras

    CERN Document Server

    Franz, Uwe

    2016-01-01

    This monograph is a progressive introduction to non-commutativity in probability theory, summarizing and synthesizing recent results about classical and quantum stochastic processes on Lie algebras. In the early chapters, focus is placed on concrete examples of the links between algebraic relations and the moments of probability distributions. The subsequent chapters are more advanced and deal with Wigner densities for non-commutative couples of random variables, non-commutative stochastic processes with independent increments (quantum Lévy processes), and the quantum Malliavin calculus. This book will appeal to advanced undergraduate and graduate students interested in the relations between algebra, probability, and quantum theory. It also addresses a more advanced audience by covering other topics related to non-commutativity in stochastic calculus, Lévy processes, and the Malliavin calculus.

  16. Linearization via the Lie Derivative

    Directory of Open Access Journals (Sweden)

    Carmen Chicone

    2000-11-01

    Full Text Available The standard proof of the Grobman-Hartman linearization theorem for a flow at a hyperbolic rest point proceeds by first establishing the analogous result for hyperbolic fixed points of local diffeomorphisms. In this exposition we present a simple direct proof that avoids the discrete case altogether. We give new proofs for Hartman's smoothness results: A ${cal C}^2$ flow is ${cal C}^1$ linearizable at a hyperbolic sink, and a ${cal C}^2$ flow in the plane is ${cal C}^1$ linearizable at a hyperbolic rest point. Also, we formulate and prove some new results on smooth linearization for special classes of quasi-linear vector fields where either the nonlinear part is restricted or additional conditions on the spectrum of the linear part (not related to resonance conditions are imposed.

  17. Advection equation analysed by two-timing method

    CERN Document Server

    Vladimirov, V A

    2016-01-01

    The aim of this paper is to study and classify the multiplicity of distinguished limits and asymptotic solutions for the advection equation with a general oscillating velocity field with the systematic use of the two-timing method. Our results are: (i) the dimensionless advection equation contains two independent small parameters, which represent the ratio of two characteristic time-scales and the spatial amplitudes of oscillations; the scaling of the variables and parameters contains Strouhal number; (ii) an infinite sequence of distinguished limits has been identified; this sequence corresponds to the successive degenerations of a drift velocity; (iii) we have derived the averaged and oscillatory equations for the first four distinguished limits; derivations are performed up to the forth orders in small parameters; (v) we have shown, that each distinguish limit solution generates an infinite number of parametric solutions; these solutions differ from each other by the slow time-scale and the amplitude of pr...

  18. Features of a rare advection-radiation event

    Institute of Scientific and Technical Information of China (English)

    PU MeiJuan; ZHANG GuoZheng; YAN WenLian; LI ZiHua

    2008-01-01

    To investigate effects of atmospheric pollutants on fog nature,a comprehensive in situ observation project was implemented in the northern suburb of Nanjing,in December of 2006. For December 24-27 there occurred a heavy fog lasting 4 d in succession. This event is of rare characteristics,namely long persistence,high concentration,tall fog top,acid fog water and explosive growth. Detailed analysis along with the causes of the fog was presented. The evidence suggests that the fog was generated by nighttime radiative cooling,maintained and developed under effects of warm,wet advection. As a result,it is an advection-radiation fog event.

  19. Lattice Boltzmann method for the fractional advection-diffusion equation.

    Science.gov (United States)

    Zhou, J G; Haygarth, P M; Withers, P J A; Macleod, C J A; Falloon, P D; Beven, K J; Ockenden, M C; Forber, K J; Hollaway, M J; Evans, R; Collins, A L; Hiscock, K M; Wearing, C; Kahana, R; Villamizar Velez, M L

    2016-04-01

    Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β, the fractional order α, and the single relaxation time τ, the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering.

  20. Spectral Theory of Advective Diffusion in the Ocean

    Science.gov (United States)

    2013-09-19

    to study this enhancement of sea ice thermal conductivity and better understand temperature data collected during a 2007 Antarctic expedition. 15...conductivity and better understand temperature data collected during a 2007 Antarctic expedition. Activities and Findings: 1. Advection-enhanced...critically on the properties of this Hilbert space. More specifically, it is only on a special subset of this space that the random operator is Hermitian

  1. Lattice Boltzmann method for the fractional advection-diffusion equation

    Science.gov (United States)

    Zhou, J. G.; Haygarth, P. M.; Withers, P. J. A.; Macleod, C. J. A.; Falloon, P. D.; Beven, K. J.; Ockenden, M. C.; Forber, K. J.; Hollaway, M. J.; Evans, R.; Collins, A. L.; Hiscock, K. M.; Wearing, C.; Kahana, R.; Villamizar Velez, M. L.

    2016-04-01

    Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β , the fractional order α , and the single relaxation time τ , the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering.

  2. NUMERICAL SIMULATIONS OF SEA ICE WITH DIFFERENT ADVECTION SCHEMES

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-ying

    2011-01-01

    Numerical simulations are carried out for sea ice with four different advection schemes to study their effects on the simulation results.The sea ice model employed here is the Sea Ice Simulator (SIS) of the Geophysical Fluid Dynamics Laboratory (GFDL) Modular Ocean Model version 4b (MOM4b) and the four advection schemes are, the upwind scheme originally used in the SIS, the Multi-Dimensional Positive Advection (MDPA) scheme, the Incremental Remapping Scheme (IRS) and the Two Step Shape Preserving (TSSP) scheme.The latter three schemes are newly introduced.To consider the interactions between sea ice and ocean, a mixed layer ocean model is introduced and coupled to the SIS.The coupled model uses a tri-polar coordinate with 120×65 grids,covering the whole earth globe, in the horizontal plane.Simulation results in the northern high latitudes are analyzed.In all simulations, the model reproduces the seasonal variation of sea ice in the northern high latitudes well.Compared with the results from the observation, the sea ice model produces some extra sea ice coverage in the Greenland Sea and Barents Sea in winter due to the exclusion of ocean current effects and the smaller simulated sea ice thickness in the Arctic basin.There are similar features among the results obtained with the introduced three advection schemes.The simulated sea ice thickness with the three newly introduced schemes are all smaller than that of the upwind scheme and the simulated sea ice velocities of movement are all smaller than that of the upwind scheme.There are more similarities shared in the results obtained with the MPDA and TSSP schemes.

  3. Lies and Deception: A Failed Reconciliation

    DEFF Research Database (Denmark)

    Broncano-Berrocal, Fernando

    2013-01-01

    The traditional view of lying says that lying is a matter of intending to deceive others by making statements that one believes to be false. Jennifer Lackey has recently defended the following version of the traditional view: A lies to B just in case (i) A states that p to B, (ii) A believes that...... is false and (iii) A intends to be deceptive to B in stating that p. I argue that, despite all the virtues that Lackey ascribes to her view, conditions (i), (ii) and (iii) are not sufficient for lying.......The traditional view of lying says that lying is a matter of intending to deceive others by making statements that one believes to be false. Jennifer Lackey has recently defended the following version of the traditional view: A lies to B just in case (i) A states that p to B, (ii) A believes that p...

  4. [Psychopathological study of lie motif in schizophrenia].

    Science.gov (United States)

    Otsuka, Koichiro; Kato, Satoshi

    2006-01-01

    The theme of a statement is called "lie motif" by the authors when schizophrenic patients say "I have lied to anybody". We tried to analyse of the psychopathological characteristics and anthropological meanings of the lie motifs in schizophrenia, which has not been thematically examined until now, based on 4 cases, and contrasting with the lie motif (Lügenmotiv) in depression taken up by A. Kraus (1989). We classified the lie motifs in schizophrenia into the following two types: a) the past directive lie motif: the patients speak about their real lie regarding it as a 'petty fault' in their distant past with self-guilty feeling, b) the present directive lie motif: the patients say repeatedly 'I have lied' (about their present speech and behavior), retreating from their previous commitments. The observed false confessions of innocent fault by the patients seem to belong to the present directed lie motif. In comparison with the lie motif in depression, it is characteristic for the lie motif in schizophrenia that the patients feel themselves to already have been caught out by others before they confess the lie. The lie motif in schizophrenia seems to come into being through the attribution process of taking the others' blame on ones' own shoulders, which has been pointed out to be common in the guilt experience in schizophrenia. The others' blame on this occasion is due to "the others' gaze" in the experience of the initial self-centralization (i.e. non delusional self-referential experience) in the early stage of schizophrenia (S. Kato 1999). The others' gaze is supposed to bring about the feeling of amorphous self-revelation which could also be regarded as the guilt feeling without content, to the patients. When the guilt feeling is bound with a past concrete fault, the patients tell the past directive lie motif. On the other hand, when the patients cannot find a past fixed content, and feel their present actions as uncertain and experience them as lies, the

  5. Learning to lie: Effects of practice on the cognitive cost of lying

    Directory of Open Access Journals (Sweden)

    Bram eVan Bockstaele

    2012-11-01

    Full Text Available Cognitive theories on deception posit that lying requires more cognitive resources than telling the truth. In line with this idea, it has been demonstrated that deceptive responses are typically associated with increased response times and higher error rates compared to truthful responses. Although the cognitive cost of lying has been assumed to be resistant to practice, it has recently been shown that people who are trained to lie can reduce this cost. In the present study (n = 42, we further explored the effects of practice on one’s ability to lie by manipulating the proportions of lie and truth-trials in a Sheffield lie test across three phases: Baseline (50% lie, 50% truth, Training (frequent-lie group: 75% lie, 25% truth; control group: 50% lie, 50% truth; and frequent-truth group: 25% lie, 75% truth, and Test (50% lie, 50% truth. The results showed that lying became easier while participants were trained to lie more often and that lying became more difficult while participants were trained to tell the truth more often. Furthermore, these effects did carry over to the test phase, but only for the specific items that were used for the training manipulation. Hence, our study confirms that relatively little practice is enough to alter the cognitive cost of lying, although this effect does not persist over time for non-practiced items.

  6. Deceivers' Responses to Challenges of Their Truthfulness: Difference between Familiar Lies and Unfamiliar Lies.

    Science.gov (United States)

    di Battista, Patrick

    1997-01-01

    Examines whether a lie's cognitive representation affects deceivers' ability to respond to probing. Shows that behavioral changes made in response to probing varied depending on whether the lie was a familiar lie or an unfamiliar lie but that none of these behaviors were related to judges' ratings of truthfulness. (SR)

  7. Non-linear thermal engineering, chaotic advection and mixing; Thermique non-lineaire, melange et advection chaotique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This conference day was jointly organized by the `university group of thermal engineering (GUT)` and the French association of thermal engineers. This book of proceedings contains 7 papers entitled: `energy spectra of a passive scalar undergoing advection by a chaotic flow`; `analysis of chaotic behaviours: from topological characterization to modeling`; `temperature homogeneity by Lagrangian chaos in a direct current flow heat exchanger: numerical approach`; ` thermal instabilities in a mixed convection phenomenon: nonlinear dynamics`; `experimental characterization study of the 3-D Lagrangian chaos by thermal analogy`; `influence of coherent structures on the mixing of a passive scalar`; `evaluation of the performance index of a chaotic advection effect heat exchanger for a wide range of Reynolds numbers`. (J.S.)

  8. The nature and role of advection in advection-diffusion equations used for modelling bed load transport

    Science.gov (United States)

    Ancey, Christophe; Bohorquez, Patricio; Heyman, Joris

    2016-04-01

    The advection-diffusion equation arises quite often in the context of sediment transport, e.g., for describing time and space variations in the particle activity (the solid volume of particles in motion per unit streambed area). Stochastic models can also be used to derive this equation, with the significant advantage that they provide information on the statistical properties of particle activity. Stochastic models are quite useful when sediment transport exhibits large fluctuations (typically at low transport rates), making the measurement of mean values difficult. We develop an approach based on birth-death Markov processes, which involves monitoring the evolution of the number of particles moving within an array of cells of finite length. While the topic has been explored in detail for diffusion-reaction systems, the treatment of advection has received little attention. We show that particle advection produces nonlocal effects, which are more or less significant depending on the cell size and particle velocity. Albeit nonlocal, these effects look like (local) diffusion and add to the intrinsic particle diffusion (dispersal due to velocity fluctuations), with the important consequence that local measurements depend on both the intrinsic properties of particle displacement and the dimensions of the measurement system.

  9. Holomorph of Lie color algebras%Lie color代数的全形

    Institute of Scientific and Technical Information of China (English)

    杨恒云

    2007-01-01

    给出Lie color代数全形的一些性质,证明Lie color代数L的全形有分解(H)(L)=L(+)Z(H)(L)(L)的充分必要条件是它是完备Lie color代数.%To the holomorph of Lie color algebras, some properties are studied. A Lie color algebra L is complete if and only if (H)(L) = L(+)Z(H)(L) (L).

  10. Discretization of partial differential equations preserving their physical symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Valiquette, F; Winternitz, P [Centre de Recherches Mathematiques, Universite de Montreal, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7 (Canada)

    2005-11-11

    A procedure for obtaining a 'minimal' discretization of a partial differential equation, preserving all of its Lie point symmetries, is presented. 'Minimal' in this case means that the differential equation is replaced by a partial difference scheme involving N difference equations, where N is the number of independent and dependent variables. We restrict ourselves to one scalar function of two independent variables. As examples, invariant discretizations of the heat, Burgers and Korteweg-de Vries equations are presented. Some exact solutions of the discrete schemes are obtained.

  11. Geometry of the Borel - de Siebenthal discrete series

    DEFF Research Database (Denmark)

    Ørsted, Bent; Wolf, Joseph A

    system”. There is a lot of fascinating geometry associated to the corresponding “Borel – de Siebenthal discrete series” representations of G0. In this paper we explore some of those geometric aspects and we work out the K0–spectra of the Borel – de Siebenthal discrete series representations. This has......Let G0 be a connected, simply connected real simple Lie group. Suppose that G0 has a compact Cartan subgroup T0, so it has discrete series representations. Relative to T0 there is a distinguished positive root system + for which there is a unique noncompact simple root , the “Borel – de Siebenthal...

  12. An Arbitrary Lagrangian-Eulerian Discretization of MHD on 3D Unstructured Grids

    Energy Technology Data Exchange (ETDEWEB)

    Rieben, R N; White, D A; Wallin, B K; Solberg, J M

    2006-06-12

    We present an arbitrary Lagrangian-Eulerian (ALE) discretization of the equations of resistive magnetohydrodynamics (MHD) on unstructured hexahedral grids. The method is formulated using an operator-split approach with three distinct phases: electromagnetic diffusion, Lagrangian motion, and Eulerian advection. The resistive magnetic dynamo equation is discretized using a compatible mixed finite element method with a 2nd order accurate implicit time differencing scheme which preserves the divergence-free nature of the magnetic field. At each discrete time step, electromagnetic force and heat terms are calculated and coupled to the hydrodynamic equations to compute the Lagrangian motion of the conducting materials. By virtue of the compatible discretization method used, the invariants of Lagrangian MHD motion are preserved in a discrete sense. When the Lagrangian motion of the mesh causes significant distortion, that distortion is corrected with a relaxation of the mesh, followed by a 2nd order monotonic remap of the electromagnetic state variables. The remap is equivalent to Eulerian advection of the magnetic flux density with a fictitious mesh relaxation velocity. The magnetic advection is performed using a novel variant of constrained transport (CT) that is valid for unstructured hexahedral grids with arbitrary mesh velocities. The advection method maintains the divergence free nature of the magnetic field and is second order accurate in regions where the solution is sufficiently smooth. For regions in which the magnetic field is discontinuous (e.g. MHD shocks) the method is limited using a novel variant of algebraic flux correction (AFC) which is local extremum diminishing (LED) and divergence preserving. Finally, we verify each stage of the discretization via a set of numerical experiments.

  13. Quantum Lie theory a multilinear approach

    CERN Document Server

    Kharchenko, Vladislav

    2015-01-01

    This is an introduction to the mathematics behind the phrase “quantum Lie algebra”. The numerous attempts over the last 15-20 years to define a quantum Lie algebra as an elegant algebraic object with a binary “quantum” Lie bracket have not been widely accepted. In this book, an alternative approach is developed that includes multivariable operations. Among the problems discussed are the following: a PBW-type theorem; quantum deformations of Kac--Moody algebras; generic and symmetric quantum Lie operations; the Nichols algebras; the Gurevich--Manin  Lie algebras;  and Shestakov--Umirbaev  operations for the Lie theory of nonassociative products.  Opening with an introduction for beginners and continuing as a textbook for graduate students in physics and mathematics, the book can also be used as a reference by more advanced readers. With the exception of the introductory chapter, the content of this monograph has not previously appeared in book form.

  14. Statistical discrete geometry

    CERN Document Server

    Ariwahjoedi, Seramika; Kosasih, Jusak Sali; Rovelli, Carlo; Zen, Freddy Permana

    2016-01-01

    Following our earlier work, we construct statistical discrete geometry by applying statistical mechanics to discrete (Regge) gravity. We propose a coarse-graining method for discrete geometry under the assumptions of atomism and background independence. To maintain these assumptions, restrictions are given to the theory by introducing cut-offs, both in ultraviolet and infrared regime. Having a well-defined statistical picture of discrete Regge geometry, we take the infinite degrees of freedom (large n) limit. We argue that the correct limit consistent with the restrictions and the background independence concept is not the continuum limit of statistical mechanics, but the thermodynamical limit.

  15. Generalized derivations of Lie triple systems

    Directory of Open Access Journals (Sweden)

    Zhou Jia

    2016-01-01

    Full Text Available In this paper, we present some basic properties concerning the derivation algebra Der (T, the quasiderivation algebra QDer (T and the generalized derivation algebra GDer (T of a Lie triple system T, with the relationship Der (T ⊆ QDer (T ⊆ GDer (T ⊆ End (T. Furthermore, we completely determine those Lie triple systems T with condition QDer (T = End (T. We also show that the quasiderivations of T can be embedded as derivations in a larger Lie triple system.

  16. 3-Leibniz bialgebras (3-Lie bialgebras)

    OpenAIRE

    2016-01-01

    In this paper by use of cohomology complex of $3$-Leibniz algebras, the definitions of Leibniz bialgebras (and Lie bialgebras) are extended for the case of $3$-Leibniz algebras. Many theorems about Leibniz bialgebras are extended and proved for the case of $3$-Leibniz bialgebras ($3$-Lie bialgebras). Moreover a new theorem on the correspondence between $3$-Leibniz bialgebra and its associated Leibniz bialgebra is proved. $3$-Lie bialgebra as particular case of the $3$-Leibniz bialgebra is inv...

  17. Killing Forms of Isotropic Lie Algebras

    CERN Document Server

    Malagon, Audrey

    2010-01-01

    This paper presents a method for computing the Killing form of an isotropic Lie algebra defined over an arbitrary field based on the Killing form of a subalgebra containing its anisotropic kernel. This approach allows for streamlined formulas for many Lie algebras of types E6 and E7 and yields a unified formula for all Lie algebras of inner type E6, including the anisotropic ones.

  18. Discrete mathematics, discrete physics and numerical methods

    OpenAIRE

    Felice Iavernaro; Donato Trigiante

    2007-01-01

    Discrete mathematics has been neglected for a long time. It has been put in the shade by the striking success of continuous mathematics in the last two centuries, mainly because continuous models in physics proved very reliable, but also because of the greater difficulty in dealing with it. This perspective has been rapidly changing in the last years owing to the needs of the numerical analysis and, more recently, of the so called discrete physics. In this paper, starting from some sentences o...

  19. ALIED: A Theory of Lie Detection

    Directory of Open Access Journals (Sweden)

    Chris N. H. Street

    2016-07-01

    Full Text Available We are very inaccurate lie detectors, and tend to believe what others tell us is the truth more often than we ought to. In fact, studies on lie detection typically describe our tendency to believe others as an error in judgment. Although people may look like hopeless lie detectors, the Adaptive Lie Detector theory (ALIED claims that people are actually making smart, informed judgments. This article explores the ALIED theory and what it means for those wanting to spot a liar.

  20. Computations in finite-dimensional Lie algebras

    Directory of Open Access Journals (Sweden)

    A. M. Cohen

    1997-12-01

    Full Text Available This paper describes progress made in context with the construction of a general library of Lie algebra algorithms, called ELIAS (Eindhoven Lie Algebra System, within the computer algebra package GAP. A first sketch of the package can be found in Cohen and de Graaf[1]. Since then, in a collaborative effort with G. Ivanyos, the authors have continued to develop algorithms which were implemented in ELIAS by the second author. These activities are part of a bigger project, called ACELA and financed by STW, the Dutch Technology Foundation, which aims at an interactive book on Lie algebras (cf. Cohen and Meertens [2]. This paper gives a global description of the main ways in which to present Lie algebras on a computer. We focus on the transition from a Lie algebra abstractly given by an array of structure constants to a Lie algebra presented as a subalgebra of the Lie algebra of n×n matrices. We describe an algorithm typical of the structure analysis of a finite-dimensional Lie algebra: finding a Levi subalgebra of a Lie algebra.

  1. Engel Subalgebras of n-Lie Algebras

    Institute of Scientific and Technical Information of China (English)

    Donald W. BARNES

    2008-01-01

    Engel subalgebras of finite-dimensional n Lie algebras are shown to have similar properties to those of Lie algebras.Using these,it is shown that an n Lie algebra,all of whose maximal subalgebras are ideals,is nilpotent.A primitive 2-soluble n Lie algebra is shown to split over its minimal ideal, and all the complements to its minimal ideal are conjugate.A subalgebra is shown to be a Cartan subalgebra if and only if it is minimal Engel,provided that the field has su .ciently many elements. Cartan subalgebras are shown to have a property analogous to intravariance.

  2. A nonlocal and periodic reaction-diffusion-advection model of a single phytoplankton species.

    Science.gov (United States)

    Peng, Rui; Zhao, Xiao-Qiang

    2016-02-01

    In this article, we are concerned with a nonlocal reaction-diffusion-advection model which describes the evolution of a single phytoplankton species in a eutrophic vertical water column where the species relies solely on light for its metabolism. The new feature of our modeling equation lies in that the incident light intensity and the death rate are assumed to be time periodic with a common period. We first establish a threshold type result on the global dynamics of this model in terms of the basic reproduction number R0. Then we derive various characterizations of R0 with respect to the vertical turbulent diffusion rate, the sinking or buoyant rate and the water column depth, respectively, which in turn give rather precise conditions to determine whether the phytoplankton persist or become extinct. Our theoretical results not only extend the existing ones for the time-independent case, but also reveal new interesting effects of the modeling parameters and the time-periodic heterogeneous environment on persistence and extinction of the phytoplankton species, and thereby suggest important implications for phytoplankton growth control.

  3. Effect of advection on transient ion concentration-polarization phenomenon

    Science.gov (United States)

    Rosentsvit, Leon; Park, Sinwook; Yossifon, Gilad

    2017-08-01

    Here, we studied the effect of advection on the transient ion concentration-polarization phenomenon in microchannel-membrane systems. Specifically, the temporal evolution of the depletion layer in a system that supports net flow rates with varying Péclet values was examined. Experiments complemented with simplified analytical one-dimensional semi-infinite modeling and numerical simulations demonstrated either suppression or enhancement of the depletion layer propagation against or with the direction of the net flow, respectively. Of particular interest was the third-species fluorescent dye ion concentration-polarization dynamics which was further explained using two-dimensional numerical simulations that accounted for the device complex geometry.

  4. Update on Advection-Diffusion Purge Flow Model

    Science.gov (United States)

    Brieda, Lubos

    2015-01-01

    Gaseous purge is commonly used in sensitive spacecraft optical or electronic instruments to prevent infiltration of contaminants and/or water vapor. Typically, purge is sized using simplistic zero-dimensional models that do not take into account instrument geometry, surface effects, and the dependence of diffusive flux on the concentration gradient. For this reason, an axisymmetric computational fluid dynamics (CFD) simulation was recently developed to model contaminant infiltration and removal by purge. The solver uses a combined Navier-Stokes and Advection-Diffusion approach. In this talk, we report on updates in the model, namely inclusion of a particulate transport model.

  5. Visualizing Vector Fields Using Line Integral Convolution and Dye Advection

    Science.gov (United States)

    Shen, Han-Wei; Johnson, Christopher R.; Ma, Kwan-Liu

    1996-01-01

    We present local and global techniques to visualize three-dimensional vector field data. Using the Line Integral Convolution (LIC) method to image the global vector field, our new algorithm allows the user to introduce colored 'dye' into the vector field to highlight local flow features. A fast algorithm is proposed that quickly recomputes the dyed LIC images. In addition, we introduce volume rendering methods that can map the LIC texture on any contour surface and/or translucent region defined by additional scalar quantities, and can follow the advection of colored dye throughout the volume.

  6. Advective heat transport in the upper carbonate aquifer beneath Winnipeg, Manitoba

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, G.A.G.; Woodbury, A.D. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

    2003-07-01

    Air conditioning and industrial cooling in Winnipeg, Manitoba requires large volumes of groundwater, with the bulk of this water pumped from the Upper Carbonate Aquifer. Pumping takes place at the erosional surface of several dipping Paleozoic carbonate units beneath the city. To prevent excessive drawdown, wastewater from these processes is reinjected into the aquifer. Heat loading from the surface, combined with this practice, leads to the creation of areas of elevated temperature within the Upper Carbonate Aquifer. An industrial area located in eastern Winnipeg is the site of the largest of these anomalies, where the aquifer's permeability is enhanced by the presence of conduits and discrete fractures. The use of numerical modeling showed that the greatest temperature anomalies occur where there are very high permeabilities, especially in the form of conduits and discrete fractures. Groundwater velocities are increased by these factors, and could result in the creation of plumes of heated water. Plumes of heated water are less likely to occur where the aquifer is thicker and conduits are absent, due to advective heat transport becoming focused between the injection well and the production well in lower permeability situations. These areas also correspond to the areas of decreased transmissivity in several parts of the Upper Carbonate Aquifer, and may not be capable of producing the required volumes of groundwater for thermal applications. Taking into account these permeability features in planning and design of non-consumptive groundwater systems in the Upper Carbonate Aquifer helps to minimize both drawdown and changes in aquifer temperature. 8 refs., 2 figs.

  7. Finite Discrete Gabor Analysis

    DEFF Research Database (Denmark)

    Søndergaard, Peter Lempel

    2007-01-01

    on the real line to be well approximated by finite and discrete Gabor frames. This method of approximation is especially attractive because efficient numerical methods exists for doing computations with finite, discrete Gabor systems. This thesis presents new algorithms for the efficient computation of finite...

  8. Discrete Mathematics Re "Tooled."

    Science.gov (United States)

    Grassl, Richard M.; Mingus, Tabitha T. Y.

    1999-01-01

    Indicates the importance of teaching discrete mathematics. Describes how the use of technology can enhance the teaching and learning of discrete mathematics. Explorations using Excel, Derive, and the TI-92 proved how preservice and inservice teachers experienced a new dimension in problem solving and discovery. (ASK)

  9. Discrete Quantum Mechanics

    CERN Document Server

    Chang, Lay Nam; Minic, Djordje; Takeuchi, Tatsu

    2012-01-01

    We construct a discrete quantum mechanics using a vector space over the Galois field GF(q). We find that the correlations in our model do not violate the Clauser-Horne-Shimony-Holt (CHSH) version of Bell's inequality, despite the fact that the predictions of this discrete quantum mechanics cannot be reproduced with any hidden variable theory.

  10. Discrete Control Systems

    CERN Document Server

    Lee, Taeyoung; McClamroch, N Harris

    2007-01-01

    Discrete control systems, as considered here, refer to the control theory of discrete-time Lagrangian or Hamiltonian systems. These discrete-time models are based on a discrete variational principle, and are part of the broader field of geometric integration. Geometric integrators are numerical integration methods that preserve geometric properties of continuous systems, such as conservation of the symplectic form, momentum, and energy. They also guarantee that the discrete flow remains on the manifold on which the continuous system evolves, an important property in the case of rigid-body dynamics. In nonlinear control, one typically relies on differential geometric and dynamical systems techniques to prove properties such as stability, controllability, and optimality. More generally, the geometric structure of such systems plays a critical role in the nonlinear analysis of the corresponding control problems. Despite the critical role of geometry and mechanics in the analysis of nonlinear control systems, non...

  11. Discrete Element Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J; Johnson, S

    2007-12-03

    The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.

  12. Discrete control systems

    CERN Document Server

    Okuyama, Yoshifumi

    2014-01-01

    Discrete Control Systems establishes a basis for the analysis and design of discretized/quantized control systemsfor continuous physical systems. Beginning with the necessary mathematical foundations and system-model descriptions, the text moves on to derive a robust stability condition. To keep a practical perspective on the uncertain physical systems considered, most of the methods treated are carried out in the frequency domain. As part of the design procedure, modified Nyquist–Hall and Nichols diagrams are presented and discretized proportional–integral–derivative control schemes are reconsidered. Schemes for model-reference feedback and discrete-type observers are proposed. Although single-loop feedback systems form the core of the text, some consideration is given to multiple loops and nonlinearities. The robust control performance and stability of interval systems (with multiple uncertainties) are outlined. Finally, the monograph describes the relationship between feedback-control and discrete ev...

  13. Continuity in Discrete Sets

    CERN Document Server

    Burgin, Mark

    2010-01-01

    Continuous models used in physics and other areas of mathematics applications become discrete when they are computerized, e.g., utilized for computations. Besides, computers are controlling processes in discrete spaces, such as films and television programs. At the same time, continuous models that are in the background of discrete representations use mathematical technology developed for continuous media. The most important example of such a technology is calculus, which is so useful in physics and other sciences. The main goal of this paper is to synthesize continuous features and powerful technology of the classical calculus with the discrete approach of numerical mathematics and computational physics. To do this, we further develop the theory of fuzzy continuous functions and apply this theory to functions defined on discrete sets. The main interest is the classical Intermediate Value theorem. Although the result of this theorem is completely based on continuity, utilization of a relaxed version of contin...

  14. The structure of complex Lie groups

    CERN Document Server

    Lee, Dong Hoon

    2001-01-01

    Complex Lie groups have often been used as auxiliaries in the study of real Lie groups in areas such as differential geometry and representation theory. To date, however, no book has fully explored and developed their structural aspects.The Structure of Complex Lie Groups addresses this need. Self-contained, it begins with general concepts introduced via an almost complex structure on a real Lie group. It then moves to the theory of representative functions of Lie groups- used as a primary tool in subsequent chapters-and discusses the extension problem of representations that is essential for studying the structure of complex Lie groups. This is followed by a discourse on complex analytic groups that carry the structure of affine algebraic groups compatible with their analytic group structure. The author then uses the results of his earlier discussions to determine the observability of subgroups of complex Lie groups.The differences between complex algebraic groups and complex Lie groups are sometimes subtle ...

  15. Classification and identification of Lie algebras

    CERN Document Server

    Snobl, Libor

    2014-01-01

    The purpose of this book is to serve as a tool for researchers and practitioners who apply Lie algebras and Lie groups to solve problems arising in science and engineering. The authors address the problem of expressing a Lie algebra obtained in some arbitrary basis in a more suitable basis in which all essential features of the Lie algebra are directly visible. This includes algorithms accomplishing decomposition into a direct sum, identification of the radical and the Levi decomposition, and the computation of the nilradical and of the Casimir invariants. Examples are given for each algorithm. For low-dimensional Lie algebras this makes it possible to identify the given Lie algebra completely. The authors provide a representative list of all Lie algebras of dimension less or equal to 6 together with their important properties, including their Casimir invariants. The list is ordered in a way to make identification easy, using only basis independent properties of the Lie algebras. They also describe certain cl...

  16. Testosterone Administration Reduces Lying in Men

    NARCIS (Netherlands)

    Wibral, M.; Dohmen, T.J.; Klingmüller, Dietrich; Weber, Bernd; Falk, Armin

    2012-01-01

    Lying is a pervasive phenomenon with important social and economic implications. However, despite substantial interest in the prevalence and determinants of lying, little is known about its biological foundations. Here we study a potential hormonal influence, focusing on the steroid hormone

  17. Lie Group Techniques for Neural Learning

    Science.gov (United States)

    2005-01-03

    Lie group techniques for Neural Learning Edinburgh June 2004 Elena Celledoni SINTEF Applied Mathematics, IMF-NTNU Lie group techniques for Neural...ORGANIZATION NAME(S) AND ADDRESS(ES) SINTEF Applied Mathematics, IMF-NTNU 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND

  18. The Killing Forms of Lie Triple Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi Xue; GAO Rui

    2009-01-01

    For Lie triple systems in the characteristic zero setting, we obtain by means of the Killing forms two criterions for semisimplicity and for solvability respectively, and then investigate the relationship among the Killing forms of a real Lie triple system To, the complexification T of To, and the realification of T.

  19. Matrix Lie Algebras and Integrable Couplings

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-Feng; GUO Fu-Kui

    2006-01-01

    Three kinds of higher-dimensional Lie algebras are given which can be used to directly construct integrable couplings of the soliton integrable systems. The relations between the Lie algebras are discussed. Finally, the integrable couplings and the Hamiltonian structure of Giachetti-Johnson hierarchy and a new integrable system are obtained, respectively.

  20. Induced Modules of Restricted Lie Superalgebras

    Institute of Scientific and Technical Information of China (English)

    刘文德

    2005-01-01

    In this paper we first prove the PBW theorem for reduced universal enveloping algebras of restricted Lie superalgebras. Then the notion of an induced module is introduced and the dimension formula of induced modules is established.Finally, using the results above, we obtain a property of induced modules pertaining to automorphisms of Lie superalgebras and isomorphisms of modules.

  1. On Nambu-Lie 3-algebra representations

    CERN Document Server

    Sochichiu, Corneliu

    2008-01-01

    We propose a recipe to construct matrix representations of Nambu--Lie 3-algebras in terms of irreducible representations of underlying Lie algebra. The case of Euclidean four-dimensional 3-algebra is considered in details. We find that representations of this 3-algebra are not possible in terms of only Hermitian matrices in spite of its Euclidean nature.

  2. Computations in finite-dimensional Lie algebras

    NARCIS (Netherlands)

    Cohen, A.M.; Graaf, W.A. de; Rónyai, L.

    2001-01-01

    This paper describes progress made in context with the construction of a general library of Lie algebra algorithms, called ELIAS (Eindhoven Lie Algebra System), within the computer algebra package GAP. A first sketch of the packagecan be found in Cohen and de Graaf[1]. Since then, in a collaborative

  3. Horizontal advection, diffusion and plankton spectra at the sea surface.

    Science.gov (United States)

    Bracco, A.; Clayton, S.; Pasquero, C.

    2009-04-01

    Plankton patchiness is ubiquitous in the oceans, and various physical and biological processes have been proposed as its generating mechanisms. However, a coherent statement on the problem is missing, due to both a small number of suitable observations and to an incomplete understanding of the properties of reactive tracers in turbulent media. Abraham (1998) suggested that horizontal advection may be the dominant process behind the observed distributions of phytoplankton and zooplankton, acting to mix tracers with longer reaction times (Rt) down to smaller scales. Conversely, Mahadevan and Campbell (2002) attributed the relative distributions of sea surface temperature and phytoplankton to small scale upwelling, where tracers with longer Rt are able to homogenize more than those with shorter reaction times. Neither of the above mechanisms can explain simultaneously the (relative) spectral slopes of temperature, phytoplankton and zooplankton. Here, with a simple advection model and a large suite of numerical experiments, we concentrate on some of the physical processes influencing the relative distributions of tracers at the ocean surface, and we investigate: 1) the impact of the spatial scale of tracer supply; 2) the role played by coherent eddies on the distribution of tracers with different Rt; 3) the role of diffusion (so far neglected). We show that diffusion determines the distribution of temperature, regardless of the nature of the forcing. We also find that coherent structures together with differential diffusion of tracers with different Rt impact the tracer distributions. This may help in understanding the highly variable nature of observed plankton spectra.

  4. Influence of Ohmic Heating on Advection-Dominated Accretion Flows

    CERN Document Server

    Bisnovatyi-Kogan, G S

    1997-01-01

    Advection-dominated, high-temperature, quasi-spherical accretion flow onto a compact object of mass M, recently considered by a number of authors, assume that the dissipation of turbulent energy of the flow heats the ions and that a constant fraction f of the dissipated energy is advected inward. It is suggested that the efficiency of conversion of accretion energy to radiation can be very much smaller than unity. However, it is likely that the flows have an equipartition magnetic field with the result that dissipation of magnetic energy at a rate comparable to that for the turbulence must occur by Ohmic heating. We argue that this heating occurs as a result of plasma instabilities and that the relevant instabilities are current driven in response to the strong electric fields parallel to the magnetic field. We argue further that these instabilities heat predominantly the electrons. We analyze a model for the radial dependence of the ion and electron temperatures of a general, possibly quasi-spherical accreti...

  5. Toward enhanced subsurface intervention methods using chaotic advection.

    Science.gov (United States)

    Trefry, Michael G; Lester, Daniel R; Metcalfe, Guy; Ord, Alison; Regenauer-Lieb, Klaus

    2012-01-01

    Many intervention activities in the terrestrial subsurface involve the need to recover/emplace distributions of scalar quantities (e.g. dissolved phase concentrations or heat) from/in volumes of saturated porous media. These scalars can be targeted by pump-and-treat methods or by amendment technologies. Application examples include in-situ leaching for metals, recovery of dissolved contaminant plumes, or utilizing heat energy in geothermal reservoirs. While conventional pumping methods work reasonably well, costs associated with maintaining pumping schedules are high and improvements in efficiency would be welcome. In this paper we discuss how transient switching of the pressure at different wells can intimately control subsurface flow, generating a range of "programmed" flows with various beneficial characteristics. Some programs produce chaotic flows which accelerate mixing, while others create encapsulating flows which can isolate fluid zones for lengthy periods. In a simplified model of an aquifer subject to balanced pumping, chaotic flow topologies have been predicted theoretically and verified experimentally using Hele-Shaw cells. Here, a survey of the key characteristics of chaotic advection is presented. Mathematical methods are used to show how these characteristics may translate into practical situations involving regional flows and heterogeneity. The results are robust to perturbations, and withstand significant aquifer heterogeneity. It is proposed that chaotic advection may form the basis of new efficient technologies for groundwater interventions. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  6. Advection-Based Sparse Data Management for Visualizing Unsteady Flow.

    Science.gov (United States)

    Guo, Hanqi; Zhang, Jiang; Liu, Richen; Liu, Lu; Yuan, Xiaoru; Huang, Jian; Meng, Xiangfei; Pan, Jingshan

    2014-12-01

    When computing integral curves and integral surfaces for large-scale unsteady flow fields, a major bottleneck is the widening gap between data access demands and the available bandwidth (both I/O and in-memory). In this work, we explore a novel advection-based scheme to manage flow field data for both efficiency and scalability. The key is to first partition flow field into blocklets (e.g. cells or very fine-grained blocks of cells), and then (pre)fetch and manage blocklets on-demand using a parallel key-value store. The benefits are (1) greatly increasing the scale of local-range analysis (e.g. source-destination queries, streak surface generation) that can fit within any given limit of hardware resources; (2) improving memory and I/O bandwidth-efficiencies as well as the scalability of naive task-parallel particle advection. We demonstrate our method using a prototype system that works on workstation and also in supercomputing environments. Results show significantly reduced I/O overhead compared to accessing raw flow data, and also high scalability on a supercomputer for a variety of applications.

  7. Multiple anisotropic collisions for advection-diffusion Lattice Boltzmann schemes

    Science.gov (United States)

    Ginzburg, Irina

    2013-01-01

    This paper develops a symmetrized framework for the analysis of the anisotropic advection-diffusion Lattice Boltzmann schemes. Two main approaches build the anisotropic diffusion coefficients either from the anisotropic anti-symmetric collision matrix or from the anisotropic symmetric equilibrium distribution. We combine and extend existing approaches for all commonly used velocity sets, prescribe most general equilibrium and build the diffusion and numerical-diffusion forms, then derive and compare solvability conditions, examine available anisotropy and stable velocity magnitudes in the presence of advection. Besides the deterioration of accuracy, the numerical diffusion dictates the stable velocity range. Three techniques are proposed for its elimination: (i) velocity-dependent relaxation entries; (ii) their combination with the coordinate-link equilibrium correction; and (iii) equilibrium correction for all links. Two first techniques are also available for the minimal (coordinate) velocity sets. Even then, the two-relaxation-times model with the isotropic rates often gains in effective stability and accuracy. The key point is that the symmetric collision mode does not modify the modeled diffusion tensor but it controls the effective accuracy and stability, via eigenvalue combinations of the opposite parity eigenmodes. We propose to reduce the eigenvalue spectrum by properly combining different anisotropic collision elements. The stability role of the symmetric, multiple-relaxation-times component, is further investigated with the exact von Neumann stability analysis developed in diffusion-dominant limit.

  8. A cryogenic circulating advective multi-pass absorption cell

    Science.gov (United States)

    Stockett, M. H.; Lawler, J. E.

    2012-03-01

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 107 cm-3. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.

  9. Neutrino-driven convection versus advection in core collapse supernovae

    CERN Document Server

    Foglizzo, T; Janka, H T

    2005-01-01

    A toy model is analyzed in order to evaluate the linear stability of the gain region immediately behind a stalled accretion shock, after core bounce. This model demonstrates that a negative entropy gradient is not sufficient to warrant linear instability. The stability criterion is governed by the ratio "chi" of the advection time through the gain region divided by the local timescale of buoyancy. The gain region is linearly stable if chi>3. For chi>3, perturbations are unstable in a limited range of horizontal wavelengths centered around twice the vertical size H of the gain region. The threshold horizontal wavenumbers k_{min} and k_{max} follow simple scaling laws such that Hk_{min}\\propto 1/chi and Hk_{max}\\propto chi. These scaling laws are understood as the consequence of a vortical-acoustic cycle within the gain region, fed by the Rayleigh-Taylor growth of vorticity perturbations during advection. The stability of short wavelength perturbations is compared to the "ablative stabilization" of accelerated ...

  10. OBSERVATION OF MAGNETIC RECONNECTION DRIVEN BY GRANULAR SCALE ADVECTION

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Zhicheng; Cao Wenda [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Blvd., Newark, NJ 07102 (United States); Ji Haisheng [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States)

    2013-06-01

    We report the first evidence of magnetic reconnection driven by advection in a rapidly developing large granule using high spatial resolution observations of a small surge event (base size {approx} 4'' Multiplication-Sign 4'') with the 1.6 m aperture New Solar Telescope at the Big Bear Solar Observatory. The observations were carried out in narrowband (0.5 A) He I 10830 A and broadband (10 A) TiO 7057 A. Since He I 10830 A triplet has a very high excitation level and is optically thin, its filtergrams enable us to investigate the surge from the photosphere through the chromosphere into the lower corona. Simultaneous space data from the Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory were used in the analysis. It is shown that the surge is spatio-temporally associated with magnetic flux emergence in the rapidly developing large granule. During the development of the granule, its advecting flow ({approx}2 km s{sup -1}) squeezed the magnetic flux into an intergranular lane area, where a magnetic flux concentration was formed and the neighboring flux with opposite magnetic polarity was canceled. During the cancellation, the surge was produced as absorption in He I 10830 A filtergrams while simultaneous EUV brightening occurred at its base. The observations clearly indicate evidence of a finest-scale reconnection process driven by the granule's motion.

  11. Local and nonlocal advection of a passive scalar

    Science.gov (United States)

    Scott, R. K.

    2006-11-01

    Passive and active scalar mixing is examined in a simple one-parameter family of two-dimensional flows based on quasi-geostrophic dynamics, in which the active scalar, the quasi-geostrophic potential vorticity, is confined to a single horizontal surface (so-called surface quasi-geostrophic dynamics) and in which a passive scalar field is also advected by the (horizontal, two-dimensional) velocity field at a finite distance from the surface. At large distances from the surface the flow is determined by the largest horizontal scales, the flow is spectrally nonlocal, and a chaotic advection-type regime dominates. At small distances, z, scaling arguments suggest a transition wavenumber kc˜1/2z, where the slope of the passive scalar spectrum changes from k-5/3, determined by local dynamics, to k-1, determined by nonlocal dynamics, analogous to the transition to a k-1 slope in the Batchelor regime in three-dimensional turbulence. Direct numerical simulations reproduce the qualitative aspects of this transition. Other characteristics of the simulated scalar fields, such as the relative dominance of coherent or filamentary structures, are also shown to depend strongly on the degree of locality.

  12. Lie symmetries and 2D Material Physics

    CERN Document Server

    Belhaj, Adil

    2014-01-01

    Inspired from Lie symmetry classification, we establish a correspondence between rank two Lie symmetries and 2D material physics. The material unit cell is accordingly interpreted as the geometry of a root system. The hexagonal cells, appearing in graphene like models, are analyzed in some details and are found to be associated with A_2 and G_2 Lie symmetries. This approach can be applied to Lie supersymmetries associated with fermionic degrees of freedom. It has been suggested that these extended symmetries can offer a new way to deal with doping material geometries. Motivated by Lie symmetry applications in high energy physics, we speculate on a possible connection with (p,q) brane networks used in the string theory compactification on singular Calabi-Yau manifolds.

  13. Characteristics of the Eysenck Personality Questionnaire Lie Scale and of Extreme Lie Scorers.

    Science.gov (United States)

    Loo, Robert

    1980-01-01

    Results of statistical analyses suggest that high lie-scorers respond honestly, and that the Lie Scale for the Eysenck Personality Inventory may reflect a personality dimension of interest rather than an extraneous and undesirable factor to be eliminated. (Author)

  14. M2 to D2 and vice versa by 3-Lie and Lie bialgebra

    Energy Technology Data Exchange (ETDEWEB)

    Aali-Javanangrouh, M.; Rezaei-Aghdam, A. [Azarbaijan Shahid Madani University, Department of Physics, Faculty of Science, Tabriz (Iran, Islamic Republic of)

    2016-11-15

    Using the concept of a 3-Lie bialgebra, which has recently been defined in arXiv:1604.04475, we construct a Bagger-Lambert-Gustavson (BLG) model for the M2-brane on a Manin triple of a special 3-Lie bialgebra. Then by using the correspondence and the relation between those 3-Lie bialgebra with Lie bialgebra, we reduce this model to an N = (4,4) WZW model (D2-brane), such that its algebraic structure is a Lie bialgebra with one 2-cocycle. In this manner by using the correspondence of the 3-Lie bialgebra and Lie bialgebra (for this special 3-Lie algebra) one can construct the M2-brane from a D2-brane and vice versa. (orig.)

  15. A-扩张Lie Rinehart代数%On the A-extended Lie Rinehart Algebras

    Institute of Scientific and Technical Information of China (English)

    陈酌; 祁玉海

    2007-01-01

    The purpose of this paper is to give a brief introduction to the category of Lie Rinehart algebras and introduces the concept of smooth manifolds associated with a unitary,commutative, associative algebra A. It especially shows that the A-extended algebra as well as the action algebra can be realized as the space of A-left invariant vector fields on a Lie group, analogous to the well known relationship of Lie algebras and Lie groups.

  16. The Prevalence of Lying in America: Three Studies of Self-Reported Lies

    Science.gov (United States)

    Serota, Kim B.; Levine, Timothy R.; Boster, Franklin J.

    2010-01-01

    This study addresses the frequency and the distribution of reported lying in the adult population. A national survey asked 1,000 U.S. adults to report the number of lies told in a 24-hour period. Sixty percent of subjects report telling no lies at all, and almost half of all lies are told by only 5% of subjects; thus, prevalence varies widely and…

  17. Homology of Lie algebra of supersymmetries and of super Poincare Lie algebra

    Energy Technology Data Exchange (ETDEWEB)

    Movshev, M.V. [Department of Mathematics, Stony Brook University, Stony Brook, NY 11794-3651 (United States); Schwarz, A., E-mail: schwarz@math.ucdavis.edu [Department of Mathematics, University of California, Davis, CA 95616 (United States); Xu, Renjun [Department of Physics, University of California, Davis, CA 95616 (United States)

    2012-01-11

    We study the homology and cohomology groups of super Lie algebras of supersymmetries and of super Poincare Lie algebras in various dimensions. We give complete answers for (non-extended) supersymmetry in all dimensions {<=}11. For dimensions D=10,11 we describe also the cohomology of reduction of supersymmetry Lie algebra to lower dimensions. Our methods can be applied to extended supersymmetry Lie algebras.

  18. A Class of Solvable Lie Algebras and Their Hom-Lie Algebra Structures

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-chao; LI Dong-ya; JIN Quan-qin

    2014-01-01

    The finite-dimensional indecomposable solvable Lie algebras s with Q2n+1 as their nilradical are studied and classified, it turns out that the dimension of s is dim Q2n+1+1. Then the Hom-Lie algebra structures on solvable Lie algebras s are calculated.

  19. Torus Bifurcation Under Discretization

    Institute of Scientific and Technical Information of China (English)

    邹永魁; 黄明游

    2002-01-01

    Parameterized dynamical systems with a simple zero eigenvalue and a couple of purely imaginary eigenvalues are considered. It is proved that this type of eigen-structure leads to torns bifurcation under certain nondegenerate conditions. We show that the discrete systems, obtained by discretizing the ODEs using symmetric, eigen-structure preserving schemes, inherit the similar torus bifurcation properties. Fredholm theory in Banach spaces is applied to obtain the global torns bifurcation. Our results complement those on the study of discretization effects of global bifurcation.

  20. Discrete density of states

    Science.gov (United States)

    Aydin, Alhun; Sisman, Altug

    2016-03-01

    By considering the quantum-mechanically minimum allowable energy interval, we exactly count number of states (NOS) and introduce discrete density of states (DOS) concept for a particle in a box for various dimensions. Expressions for bounded and unbounded continua are analytically recovered from discrete ones. Even though substantial fluctuations prevail in discrete DOS, they're almost completely flattened out after summation or integration operation. It's seen that relative errors of analytical expressions of bounded/unbounded continua rapidly decrease for high NOS values (weak confinement or high energy conditions), while the proposed analytical expressions based on Weyl's conjecture always preserve their lower error characteristic.

  1. The role of advection in a two-species competition model

    CERN Document Server

    Averill, Isabel; Lou, Yuan

    2017-01-01

    The effects of weak and strong advection on the dynamics of reaction-diffusion models have long been studied. In contrast, the role of intermediate advection remains poorly understood. For example, concentration phenomena can occur when advection is strong, providing a mechanism for the coexistence of multiple populations, in contrast with the situation of weak advection where coexistence may not be possible. The transition of the dynamics from weak to strong advection is generally difficult to determine. In this work the authors consider a mathematical model of two competing populations in a spatially varying but temporally constant environment, where both species have the same population dynamics but different dispersal strategies: one species adopts random dispersal, while the dispersal strategy for the other species is a combination of random dispersal and advection upward along the resource gradient. For any given diffusion rates the authors consider the bifurcation diagram of positive steady states by u...

  2. Introduction to the theory of Lie groups

    CERN Document Server

    Godement, Roger

    2017-01-01

    This textbook covers the general theory of Lie groups. By first considering the case of linear groups (following von Neumann's method) before proceeding to the general case, the reader is naturally introduced to Lie theory. Written by a master of the subject and influential member of the Bourbaki group, the French edition of this textbook has been used by several generations of students. This translation preserves the distinctive style and lively exposition of the original. Requiring only basics of topology and algebra, this book offers an engaging introduction to Lie groups for graduate students and a valuable resource for researchers.

  3. Quasi-big\\`ebres de Lie et cohomologie d'alg\\`ebre de Lie

    CERN Document Server

    Bangoura, Momo

    2010-01-01

    Lie quasi-bialgebras are natural generalisations of Lie bialgebras introduced by Drinfeld. To any Lie quasi-bialgebra structure of finite-dimensional (G, \\mu, \\gamma ,\\phi ?), correspond one Lie algebra structure on D = G\\oplus G*, called the double of the given Lie quasi-bialgebra. We show that there exist on \\Lambda G, the exterior algebra of G, a D-module structure and we establish an isomorphism of D-modules between \\Lambda D and End(\\Lambda G), D acting on \\Lambda D by the adjoint action.

  4. Induced Lie Algebras of a Six-Dimensional Matrix Lie Algebra

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-Feng; LIU Jing

    2008-01-01

    By using a six-dimensional matrix Lie algebra [Y.F. Zhang and Y. Wang, Phys. Lett. A 360 (2006) 92], three induced Lie algebras are constructed. One of them is obtained by extending Lie bracket, the others are higher-dimensional complex Lie algebras constructed by using linear transformations. The equivalent Lie algebras of the later two with multi-component forms are obtained as well. As their applications, we derive an integrable coupling and quasi-Hamiltonian structure of the modified TC hierarchy of soliton equations.

  5. Tomography-based monitoring of isothermal snow metamorphism under advective conditions

    OpenAIRE

    P. P. Ebner; M. Schneebeli; A. Steinfeld

    2015-01-01

    Time-lapse X-ray micro-tomography was used to investigate the structural dynamics of isothermal snow metamorphism exposed to an advective airflow. Diffusion and advection across the snow pores were analysed in controlled laboratory experiments. The 3-D digital geometry obtained by tomographic scans was used in direct pore-level numerical simulations to determine the effective transport properties. The results showed that isothermal advection with saturated air have no influence...

  6. A conservative orbital advection scheme for simulations of magnetized shear flows with the PLUTO code

    Science.gov (United States)

    Mignone, A.; Flock, M.; Stute, M.; Kolb, S. M.; Muscianisi, G.

    2012-09-01

    Context. Explicit numerical computations of hypersonic or super-fast differentially rotating disks are subject to the time-step constraint imposed by the Courant condition, according to which waves cannot travel more than a fraction of a cell during a single time-step update. When the bulk orbital velocity largely exceeds any other wave speed (e.g., sound or Alfvén), as computed in the rest frame, the time step is considerably reduced and an unusually large number of steps may be necessary to complete the computation. Aims: We present a robust numerical scheme to overcome the Courant limitation by improving and extending the algorithm previously known as FARGO (fast advection in rotating gaseous objects) to the equations of magnetohydrodynamics (MHD) using a more general formalism. The proposed scheme conserves total angular momentum and energy to machine precision and works in cartesian, cylindrical, or spherical coordinates. The algorithm has been implemented in the next release of the PLUTO code for astrophysical gasdynamics and is suitable for local or global simulations of accretion or proto-planetary disk models. Methods: By decomposing the total velocity into an average azimuthal contribution and a residual term, the algorithm approaches the solution of the MHD equations through two separate steps corresponding to a linear transport operator in the direction of orbital motion and a standard nonlinear solver applied to the MHD equations written in terms of the residual velocity. Since the former step is not subject to any stability restriction, the Courant condition is computed only in terms of the residual velocity, leading to substantially larger time steps. The magnetic field is advanced in time using the constrained transport method in order to fulfill the divergence-free condition. Furthermore, conservation of total energy and angular momentum is enforced at the discrete level by properly expressing the source terms in terms of upwind Godunov fluxes

  7. Pearls of Discrete Mathematics

    CERN Document Server

    Erickson, Martin

    2009-01-01

    Presents methods for solving counting problems and other types of problems that involve discrete structures. This work illustrates the relationship of these structures to algebra, geometry, number theory and combinatorics. It addresses topics such as information and game theories

  8. Discrete fractional calculus

    CERN Document Server

    Goodrich, Christopher

    2015-01-01

    This text provides the first comprehensive treatment of the discrete fractional calculus. Experienced researchers will find the text useful as a reference for discrete fractional calculus and topics of current interest. Students who are interested in learning about discrete fractional calculus will find this text to provide a useful starting point. Several exercises are offered at the end of each chapter and select answers have been provided at the end of the book. The presentation of the content is designed to give ample flexibility for potential use in a myriad of courses and for independent study. The novel approach taken by the authors includes a simultaneous treatment of the fractional- and integer-order difference calculus (on a variety of time scales, including both the usual forward and backwards difference operators). The reader will acquire a solid foundation in the classical topics of the discrete calculus while being introduced to exciting recent developments, bringing them to the frontiers of the...

  9. Advection of nematic liquid crystals by chaotic flow

    CERN Document Server

    O'Naraigh, Lennon

    2016-01-01

    Consideration is given to the effects of inhomogeneous shear flow (both regular and chaotic) on nematic liquid crystals in a planar two-dimensional geometry. The Landau-de Gennes equation coupled to an externally-prescribed flow field is the basis for the study: this is solved numerically in a periodic spatial domain. The focus is on a limiting case where the advection is passive, such that variations in the liquid-crystal properties do not feed back into the equation of motion for the uid velocity. The numerical simulations demonstrate that the coarsening of the liquid-crystal domains is arrested by the ow. The nature of the arrest is different depending on whether the flow is regular or chaotic. For the specific case where tumbling is important, the flow has a strong effect on the the liquid-crystal morphology: this provides a mechanism for controlling the shape of the liquid-crystal domains.

  10. Magnetic field advection in two interpenetrating plasma streams

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D. D.; Kugland, N. L.; Levy, M. C.; Plechaty, C.; Ross, J. S.; Park, H. S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2013-03-15

    Laser-generated colliding plasma streams can serve as a test-bed for the study of various astrophysical phenomena and the general physics of self-organization. For streams of a sufficiently high kinetic energy, collisions between the ions of one stream with the ions of the other stream are negligible, and the streams can penetrate through each other. On the other hand, the intra-stream collisions for high-Mach-number flows can still be very frequent, so that each stream can be described hydrodynamically. This paper presents an analytical study of the effects that these interpenetrating streams have on large-scale magnetic fields either introduced by external coils or generated in the plasma near the laser targets. Specifically, a problem of the frozen-in constraint is assessed and paradoxical features of the field advection in this system are revealed. A possibility of using this system for studies of magnetic reconnection is mentioned.

  11. The Discrete Wavelet Transform

    Science.gov (United States)

    1991-06-01

    focuses on bringing together two separately motivated implementations of the wavelet transform , the algorithm a trous and Mallat’s multiresolution...decomposition. These algorithms are special cases of a single filter bank structure, the discrete wavelet transform , the behavior of which is governed by...nonorthogonal multiresolution algorithm for which the discrete wavelet transform is exact. Moreover, we show that the commonly used Lagrange a trous

  12. Discrete computational structures

    CERN Document Server

    Korfhage, Robert R

    1974-01-01

    Discrete Computational Structures describes discrete mathematical concepts that are important to computing, covering necessary mathematical fundamentals, computer representation of sets, graph theory, storage minimization, and bandwidth. The book also explains conceptual framework (Gorn trees, searching, subroutines) and directed graphs (flowcharts, critical paths, information network). The text discusses algebra particularly as it applies to concentrates on semigroups, groups, lattices, propositional calculus, including a new tabular method of Boolean function minimization. The text emphasize

  13. A high-order splitting scheme for the advection-diffusion equation of pollutants

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A high-order splitting scheme for the advection-diffusion equation of pollutants is proposed in this paper. The multidimensional advection-diffusion equation is splitted into several one-dimensional equations that are solved by the scheme. Only three spatial grid points are needed in each direction and the scheme has fourth-order spatial accuracy. Several typically pure advection and advection-diffusion problems are simulated. Numerical results show that the accuracy of the scheme is much higher than that of the classical schemes and the scheme can be efficiently solved with little programming effort.

  14. Hybrid Topological Lie-Hamiltonian Learning in Evolving Energy Landscapes

    Science.gov (United States)

    Ivancevic, Vladimir G.; Reid, Darryn J.

    2015-11-01

    In this Chapter, a novel bidirectional algorithm for hybrid (discrete + continuous-time) Lie-Hamiltonian evolution in adaptive energy landscape-manifold is designed and its topological representation is proposed. The algorithm is developed within a geometrically and topologically extended framework of Hopfield's neural nets and Haken's synergetics (it is currently designed in Mathematica, although with small changes it could be implemented in Symbolic C++ or any other computer algebra system). The adaptive energy manifold is determined by the Hamiltonian multivariate cost function H, based on the user-defined vehicle-fleet configuration matrix W, which represents the pseudo-Riemannian metric tensor of the energy manifold. Search for the global minimum of H is performed using random signal differential Hebbian adaptation. This stochastic gradient evolution is driven (or, pulled-down) by `gravitational forces' defined by the 2nd Lie derivatives of H. Topological changes of the fleet matrix W are observed during the evolution and its topological invariant is established. The evolution stops when the W-topology breaks down into several connectivity-components, followed by topology-breaking instability sequence (i.e., a series of phase transitions).

  15. The Frattini Subalgebra of Restricted Lie Superalgebras

    Institute of Scientific and Technical Information of China (English)

    Liang Yun CHEN; Dao Ji MENG; Yong Zheng ZHANG

    2006-01-01

    In the present paper, we study the Frattini subalgebra of a restricted Lie superalgebra (L, [p]). We show first that if L = A1 (⊙) A2 (⊙) … (⊙) An, then φp (L) = φp (A1) + φp (A2) +… +φp (An),where each Ai is a p-ideal of L. We then obtain two results: F(L) = φ(L) = J(L) = L(1) if and only if L is nilpotent; Fp(L) and F(L) are nilpotent ideals of L if L is solvable. In addition, necessary and sufficient conditions are found for φp-free restricted Lie superalgebras. Finally, we discuss the relationships of E-p-restricted Lie superalgebras and E-restricted Lie superalgebras.

  16. Linearization from Complex Lie Point Transformations

    Directory of Open Access Journals (Sweden)

    Sajid Ali

    2014-01-01

    Full Text Available Complex Lie point transformations are used to linearize a class of systems of second order ordinary differential equations (ODEs which have Lie algebras of maximum dimension d, with d≤4. We identify such a class by employing complex structure on the manifold that defines the geometry of differential equations. Furthermore we provide a geometrical construction of the procedure adopted that provides an analogue in R3 of the linearizability criteria in R2.

  17. Lie Superalgebras arising from bosonic representation

    CERN Document Server

    Jing, Naihuan

    2012-01-01

    A 2-toroidal Lie superalgebra is constructed using bosonic fields and a ghost field. The superalgebra contains $osp(1|2n)^{(1)}$ as a distinguished subalgebra and behaves similarly to the toroidal Lie superalgebra of type $B(0, n)$. Furthermore this algebra is a central extension of the algebra $osp(1|2n)\\otimes \\mathbb C[s, s^{-1}, t,t^{-1}]$.

  18. Noncommutative geometry with graded differential Lie algebras

    Science.gov (United States)

    Wulkenhaar, Raimar

    1997-06-01

    Starting with a Hilbert space endowed with a representation of a unitary Lie algebra and an action of a generalized Dirac operator, we develop a mathematical concept towards gauge field theories. This concept shares common features with the Connes-Lott prescription of noncommutative geometry, differs from that, however, by the implementation of unitary Lie algebras instead of associative * -algebras. The general scheme is presented in detail and is applied to functions ⊗ matrices.

  19. Post-Lie algebras and factorization theorems

    Science.gov (United States)

    Ebrahimi-Fard, Kurusch; Mencattini, Igor; Munthe-Kaas, Hans

    2017-09-01

    In this note we further explore the properties of universal enveloping algebras associated to a post-Lie algebra. Emphasizing the role of the Magnus expansion, we analyze the properties of group like-elements belonging to (suitable completions of) those Hopf algebras. Of particular interest is the case of post-Lie algebras defined in terms of solutions of modified classical Yang-Baxter equations. In this setting we will study factorization properties of the aforementioned group-like elements.

  20. Constructing semisimple subalgebras of semisimple Lie algebras

    CERN Document Server

    de Graaf, Willem A

    2010-01-01

    Algorithms are described that help with obtaining a classification of the semisimple subalgebras of a given semisimple Lie algebra, up to linear equivalence. The algorithms have been used to obtain classifications of the semisimple subalgebras of the simple Lie algebras of ranks <= 8. These have been made available as a database inside the SLA package of GAP4. The subalgebras in this database are explicitly given, as well as the inclusion relations among them.

  1. Lie Admissible Non-Associative Algebras

    Institute of Scientific and Technical Information of China (English)

    H.Mohammad Ahmadi; Ki-Bong Nam; Jonathan Pakinathan

    2005-01-01

    A non-associative ring which contains a well-known associative ring or Lie ring is interesting. In this paper, a method to construct a Lie admissible non-associative ring is given; a class of simple non-associative algebras is obtained; all the derivations of the non-associative simple N0,0,1 algebra defined in this paper are determined; and finally, a solid algebra is defined.

  2. Central extension of graded Lie algebras

    CERN Document Server

    Welte, Angelika

    2010-01-01

    In this thesis we describe the universal central extension of two important classes of so-called root-graded Lie algebras defined over a commutative associative unital ring $k.$ Root-graded Lie algebras are Lie algebras which are graded by the root lattice of a locally finite root system and contain enough $\\mathfrak{sl}_2$-triples to separate the homogeneous spaces of the grading. Examples include the infinite rank analogs of the simple finite-dimensional complex Lie algebras. \\\\ In the thesis we show that in general the universal central extension of a root-graded Lie algebra $L$ is not root-graded anymore, but that we can measure quite easily how far it is away from being so, using the notion of degenerate sums, introduced by van der Kallen. We then concentrate on root-graded Lie algebras which are graded by the root systems of type $A$ with rank at least 2 and of type $C$. For them one can use the theory of Jordan algebras.

  3. Investigation of structure and properties of novel multi-layer clay nanocomposite films produced controllably by continuous chaotic advection blending

    Science.gov (United States)

    Mahesha, Chaitra

    A unique processing technique based on chaotic advection developed at Clemson University and shown to controllably produce structured materials in the past was employed to produce structured nanocomposites with a high degree of clay orientation as well as localization of platelets within layers of nanoscale thicknesses. Continuous lengths of nanocomposites with different clay contents were extruded in the form of films by feeding separately melts of virgin polyamide-6 polymer and polyamide 6-clay masterbatch into a continuous chaotic advection blender. A variety of composite structures were producible at fixed clay compositions. The internal structure was characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Nanocomposites with novel in-situ multi-layered structures and a high degree of platelet orientation were formed by the recursive stretching and folding of the melt domains due to chaotic advection. Clay platelets were localized within discrete regions to form alternating virgin and platelet-rich layers leading to a hierarchical structure with multiple nano-scales. The thicknesses of the layers reduced with prolonged chaotic advection, eventually leading to nanocomposites in which the multi-layering was no longer discernible. The oriented platelets appeared to be homogenously dispersed through the bulk of the nanocomposite. Investigation of the morphology of the matrix by XRD showed that the homogeneity of the crystalline phase and the orientation of polymer chains parallel to the film surface increased with increased chaotic advection. Also, as the layer thickness reduced, the number of polymer chains restricted by clay platelets increased causing the gamma-crystalline fraction to increase. While XRD results suggested a change in total crystallinity with chaotic advection and clay content but without a specific trend, no change in crystallinity was measured by DSC. Such contradictions are

  4. A twisted generalization of Lie-Yamaguti algebras

    CERN Document Server

    Gaparayi, Donatien

    2010-01-01

    A twisted generalization of Lie-Yamaguti algebras, called Hom-Lie-Yamaguti algebras, is defined. Hom-Lie-Yamaguti algebras generalize Hom-Lie triple systems (and susequently ternary Hom-Nambu algebras) and Hom-Lie algebras in the same way as Lie-Yamaguti algebras generalize Lie triple systems and Lie algebras. It is shown that the category of Hom-Lie-Yamaguti algebras is closed under twisting by self-morphisms. Constructions of Hom-Lie-Yamaguti algebras from classical Lie-Yamaguti algebras and Malcev algebras are given. It is observed that, when the ternary operation of a Hom-Lie-Yamaguti algebra expresses through its binary one in a specific way, then such a Hom-Lie-Yamaguti algebra is a Hom-Malcev algebra.

  5. Using a Multiregion Model to Study the Effects of Advective and Diffusive Mass Transfer on Local Physical Nonequilibrium and Solute Mobility in a Structured Soil

    Science.gov (United States)

    Gwo, J. P.; Jardine, P. M.; Wilson, G. V.; Yeh, G. T.

    1996-03-01

    Waste management problems for shallow land burial facilities in the humid eastern United States are usually complicated by slow but continuous movement of wastes through the soil matrix and discrete but rapid pulses of wastes through macropores and fractures. Multiple-pore-region models employed to describe flow and solute transport in the soils usually consist of multiple mass transfer coefficients that cannot be measured experimentally, and their effects on subsurface mass transport are poorly understood. The objective of this research was to study the individual and concurrent effects of interaggregate advection and diffusion on mass transport in a structured soil. The interactions of these two mass transfer processes and local solute concentration equilibrium are examined for a heterogeneous soil. Pore region water retention, hydraulic conductivity, and dispersivities, obtained from independent measurements and published calibration results, were used to test a novel three-pore-region, one-dimensional numerical model. Advective and diffusive mass transfer coefficients were estimated using mass transfer equations and fracture spacings published in the literature. The mass transfer coefficients were then varied systematically, and the sensitivity of local fluid pressure and solute concentration nonequilibrium to interregion mass transfer were analyzed. Our results indicated that time-dependent interaggregate advection and diffusion were important processes controlling solute mobility in heterogeneous media. Under transient flow conditions, interaggregate advection may reduce the significance of interaggregate diffusion that otherwise dominates interaggregate mass transfer under steady state conditions. Nonetheless, the equilibrium of local solute concentrations was 20 times more sensitive to diffusive mass transfer than to advective mass transfer, which suggests that site characterization efforts should be directed more toward the former process. Unfortunately

  6. Detecting true lies:police officers' ability to detect suspects' lies

    OpenAIRE

    Mann, Samantha; Vrij, Aldert; Bull, Ray

    2004-01-01

    Ninety-nine police officers, not identified in previous research as belonging to groups which are superior in lie detection, attempted to detect truths and lies told by suspects during their videotaped police interviews. Accuracy rates were higher than typically found in deception research and reached levels similar to those obtained by specialized lie detectors in previous research. Accuracy was positively correlated with perceived experience in interviewing suspects and with mentioning cues...

  7. Algebraic dynamics solution to and algebraic dynamics algorithm for nonlinear advection equation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Algebraic dynamics approach and algebraic dynamics algorithm for the solution of nonlinear partial differential equations are applied to the nonlinear advection equa-tion. The results show that the approach is effective for the exact analytical solu-tion and the algorithm has higher precision than other existing algorithms in nu-merical computation for the nonlinear advection equation.

  8. Nucleosynthesis in Advective Accretion Disks Around Galactic and Extra-Galactic Black Holes

    CERN Document Server

    Mukhopadhyay, B

    1998-01-01

    We compute the nucleosynthesis of materials inside advective disks around black holes. We show that composition of incoming matter can change significantly depending on the accretion rate and accretion disks. These works are improvements on the earlier works in thick accretion disks of Chakrabarti, Jin & Arnett (1987) in presence of advection in the flow.

  9. Discrete-Event Simulation

    Directory of Open Access Journals (Sweden)

    Prateek Sharma

    2015-04-01

    Full Text Available Abstract Simulation can be regarded as the emulation of the behavior of a real-world system over an interval of time. The process of simulation relies upon the generation of the history of a system and then analyzing that history to predict the outcome and improve the working of real systems. Simulations can be of various kinds but the topic of interest here is one of the most important kind of simulation which is Discrete-Event Simulation which models the system as a discrete sequence of events in time. So this paper aims at introducing about Discrete-Event Simulation and analyzing how it is beneficial to the real world systems.

  10. Discrete Anderson Speckle

    CERN Document Server

    Kondakci, H Esat; Saleh, Bahaa E A

    2016-01-01

    When a disordered array of coupled waveguides is illuminated with an extended coherent optical field, discrete speckle develops: partially coherent light with a granular intensity distribution on the lattice sites. The same paradigm applies to a variety of other settings in photonics, such as imperfectly coupled resonators or fibers with randomly coupled cores. Through numerical simulations and analytical modeling, we uncover a set of surprising features that characterize discrete speckle in one- and two-dimensional lattices known to exhibit transverse Anderson localization. Firstly, the fingerprint of localization is embedded in the fluctuations of the discrete speckle and is revealed in the narrowing of the spatial coherence function. Secondly, the transverse coherence length (or speckle grain size) is frozen during propagation. Thirdly, the axial coherence depth is independent of the axial position, thereby resulting in a coherence voxel of fixed volume independently of position. We take these unique featu...

  11. Discrete systems and integrability

    CERN Document Server

    Hietarinta, J; Nijhoff, F W

    2016-01-01

    This first introductory text to discrete integrable systems introduces key notions of integrability from the vantage point of discrete systems, also making connections with the continuous theory where relevant. While treating the material at an elementary level, the book also highlights many recent developments. Topics include: Darboux and Bäcklund transformations; difference equations and special functions; multidimensional consistency of integrable lattice equations; associated linear problems (Lax pairs); connections with Padé approximants and convergence algorithms; singularities and geometry; Hirota's bilinear formalism for lattices; intriguing properties of discrete Painlevé equations; and the novel theory of Lagrangian multiforms. The book builds the material in an organic way, emphasizing interconnections between the various approaches, while the exposition is mostly done through explicit computations on key examples. Written by respected experts in the field, the numerous exercises and the thoroug...

  12. Discrete Classical Electromagnetic Fields

    CERN Document Server

    De Souza, M M

    1997-01-01

    The classical electromagnetic field of a spinless point electron is described in a formalism with extended causality by discrete finite transverse point-vector fields with discrete and localized point interactions. These fields are taken as a classical representation of photons, ``classical photons". They are all transversal photons; there are no scalar nor longitudinal photons as these are definitely eliminated by the gauge condition. The angular distribution of emitted photons coincides with the directions of maximum emission in the standard formalism. The Maxwell formalism and its standard field are retrieved by the replacement of these discrete fields by their space-time averages, and in this process scalar and longitudinal photons are necessarily created and added. Divergences and singularities are by-products of this averaging process. This formalism enlighten the meaning and the origin of the non-physical photons, the ones that violate the Lorentz condition in manifestly covariant quantization methods.

  13. Lie n-algebras of BPS charges

    CERN Document Server

    Sati, Hisham

    2015-01-01

    We uncover higher algebraic structures on Noether currents and BPS charges. It is known that equivalence classes of conserved currents form a Lie algebra. We show that at least for target space symmetries of higher parameterized WZW-type sigma-models this naturally lifts to a Lie (p+1)-algebra structure on the Noether currents themselves. Applied to the Green-Schwarz-type action functionals for super p-brane sigma-models this yields super Lie (p+1)-algebra refinements of the traditional BPS brane charge extensions of supersymmetry algebras. We discuss this in the generality of higher differential geometry, where it applies also to branes with (higher) gauge fields on their worldvolume. Applied to the M5-brane sigma-model we recover and properly globalize the M-theory super Lie algebra extension of 11-dimensional superisometries by 2-brane and 5-brane charges. Passing beyond the infinitesimal Lie theory we find cohomological corrections to these charges in higher analogy to the familiar corrections for D-brane...

  14. Introductory discrete mathematics

    CERN Document Server

    Balakrishnan, V K

    2010-01-01

    This concise text offers an introduction to discrete mathematics for undergraduate students in computer science and mathematics. Mathematics educators consider it vital that their students be exposed to a course in discrete methods that introduces them to combinatorial mathematics and to algebraic and logical structures focusing on the interplay between computer science and mathematics. The present volume emphasizes combinatorics, graph theory with applications to some stand network optimization problems, and algorithms to solve these problems.Chapters 0-3 cover fundamental operations involv

  15. Discrete breathers in crystals

    Science.gov (United States)

    Dmitriev, S. V.; Korznikova, E. A.; Baimova, Yu A.; Velarde, M. G.

    2016-05-01

    It is well known that periodic discrete defect-containing systems, in addition to traveling waves, support vibrational defect-localized modes. It turned out that if a periodic discrete system is nonlinear, it can support spatially localized vibrational modes as exact solutions even in the absence of defects. Since the nodes of the system are all on equal footing, it is only through the special choice of initial conditions that a group of nodes can be found on which such a mode, called a discrete breather (DB), will be excited. The DB frequency must be outside the frequency range of the small-amplitude traveling waves. Not resonating with and expending no energy on the excitation of traveling waves, a DB can theoretically conserve its vibrational energy forever provided no thermal vibrations or other perturbations are present. Crystals are nonlinear discrete systems, and the discovery in them of DBs was only a matter of time. It is well known that periodic discrete defect-containing systems support both traveling waves and vibrational defect-localized modes. It turns out that if a periodic discrete system is nonlinear, it can support spatially localized vibrational modes as exact solutions even in the absence of defects. Because the nodes of the system are all on equal footing, only a special choice of the initial conditions allows selecting a group of nodes on which such a mode, called a discrete breather (DB), can be excited. The DB frequency must be outside the frequency range of small-amplitude traveling waves. Not resonating with and expending no energy on the excitation of traveling waves, a DB can theoretically preserve its vibrational energy forever if no thermal vibrations or other perturbations are present. Crystals are nonlinear discrete systems, and the discovery of DBs in them was only a matter of time. Experimental studies of DBs encounter major technical difficulties, leaving atomistic computer simulations as the primary investigation tool. Despite

  16. Discrete and computational geometry

    CERN Document Server

    Devadoss, Satyan L

    2011-01-01

    Discrete geometry is a relatively new development in pure mathematics, while computational geometry is an emerging area in applications-driven computer science. Their intermingling has yielded exciting advances in recent years, yet what has been lacking until now is an undergraduate textbook that bridges the gap between the two. Discrete and Computational Geometry offers a comprehensive yet accessible introduction to this cutting-edge frontier of mathematics and computer science. This book covers traditional topics such as convex hulls, triangulations, and Voronoi diagrams, as well a

  17. Deformed discrete symmetries

    Science.gov (United States)

    Arzano, Michele; Kowalski-Glikman, Jerzy

    2016-09-01

    We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of κ-deformations of the Poincaré algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter κ to be derived via precision measurements of discrete symmetries and CPT.

  18. On classification of discrete, scalar-valued Poisson Brackets

    CERN Document Server

    Parodi, Emanuele

    2011-01-01

    We address the problem of classifying discrete differential-geometric Poisson brackets (dDGPBs) of any fixed order on target space of dimension 1. It is proved that these Poisson brackets (PBs) are in one-to-one correspondence with the intersection points of certain projective hypersurfaces. In addition, they can be reduced to cubic PB of standard Volterra lattice by discrete Miura-type transformations. Finally, improving a consolidation lattice procedure, we obtain new families of non-degenerate, vector-valued and first order dDGPBs, which can be considered in the framework of admissible Lie-Poisson group theory.

  19. Standing Shock Instability in Advection-Dominated Accretion Flows

    CERN Document Server

    Le, Truong; Wolff, Michael T; Becker, Peter A; Putney, Joy

    2015-01-01

    Depending on the values of the energy and angular momentum per unit mass in the gas supplied at large radii, inviscid advection-dominated accretion flows can display velocity profiles with either pre-shock deceleration or pre-shock acceleration. Nakayama has shown that these two types of flow configurations are expected to have different stability properties. By employing the Chevalier & Imamura linearization method and the Nakayama instability boundary conditions, we discover that there are regions of parameters space where disk/shocks with outflows can be stable or unstable. In region of instability, we find that pre-shock deceleration is always unstable to the zeroth mode with zero frequency of oscillation, but is always stable to the fundamental and overtones. Furthermore, we also find that pre-shock acceleration is always unstable to the zeroth mode, and that the fundamental and overtones become increasingly less stable as the shock location moves away from the horizon when the disk half-height expan...

  20. Implementation of Two Component Advective Flow Solution in XSPEC

    CERN Document Server

    Debnath, Dipak; Mondal, Santanu

    2014-01-01

    Spectral and Temporal properties of black hole candidates can be explained reasonably well using Chakrabarti-Titarchuk solution of two component advective flow (TCAF). This model requires two accretion rates, namely, the Keplerian disk accretion rate and the halo accretion rate, the latter being composed of a sub-Keplerian, low angular momentum flow which may or may not develop a shock. In this solution, the relevant parameter is the relative importance of the halo (which creates the Compton cloud region) rate with respect to the Keplerian disk rate (soft photon source). Though this model has been used earlier to manually fit data of several black hole candidates quite satisfactorily, for the first time, we made it user friendly by implementing it into XSPEC software of GSFC/NASA. This enables any user to extract physical parameters of the accretion flows, such as two accretion rates, the shock location, the shock strength etc. for any black hole candidate. We provide some examples of fitting a few cases usin...

  1. Memory effects in chaotic advection of inertial particles

    Science.gov (United States)

    Daitche, Anton; Tél, Tamás

    2014-07-01

    A systematic investigation of the effect of the history force on particle advection is carried out for both heavy and light particles. General relations are given to identify parameter regions where the history force is expected to be comparable with the Stokes drag. As an illustrative example, a paradigmatic two-dimensional flow, the von Kármán flow is taken. For small (but not extremely small) particles all investigated dynamical properties turn out to heavily depend on the presence of memory when compared to the memoryless case: the history force generates a rather non-trivial dynamics that appears to weaken (but not to suppress) inertial effects, it enhances the overall contribution of viscosity. We explore the parameter space spanned by the particle size and the density ratio, and find a weaker tendency for accumulation in attractors and for caustics formation. The Lyapunov exponent of transients becomes larger with memory. Periodic attractors are found to have a very slow, {{t}^{-1/2}} type convergence towards the asymptotic form. We find that the concept of snapshot attractors is useful to understand this slow convergence: an ensemble of particles converges exponentially fast towards a snapshot attractor, which undergoes a slow shift for long times.

  2. Memory Effects in Chaotic Advection of Inertial Particles

    CERN Document Server

    Daitche, Anton

    2014-01-01

    A systematic investigation of the effect of the history force on particle advection is carried out for both heavy and light particles. General relations are given to identify parameter regions where the history force is expected to be comparable with the Stokes drag. As an illustrative example, a paradigmatic two-dimensional flow, the von K\\'arm\\'an flow is taken. For small (but not extremely small) particles all investigated dynamical properties turn out to heavily depend on the presence of memory when compared to the memoryless case: the history force generates a rather nontrivial dynamics that appears to weaken (but not to suppress) inertial effects, it enhances the overall contribution of viscosity. We explore the parameter space spanned by the particle size and the density ratio, and find a weaker tendency for accumulation in attractors and for caustics formation. The Lyapunov exponent of transients becomes larger with memory. Periodic attractors are found to have a very slow, $t^{-1/2}$ type convergence...

  3. Modelling the advection of herring larvae in the North Sea

    Science.gov (United States)

    Bartsch, J.; Brander, K.; Heath, M.; Munk, P.; Richardson, K.; Svendsen, E.

    1989-08-01

    THE number of fish at the age of first capture in a fishery (recruitment) is dependent on the production of eggs by the parent stock and the survival of early life stages (eggs, larvae and juveniles). In many pelagic fish species the survival of larvae depends on transport from spawning to nursery areas1. To investigate larval transport processes for North Sea herring (Clupea harengus L.) we have modelled in three dimensions the advection of autumn-spawned larvae during the winter of 1987-1988 and compared the results with sequential field data on the actual distribution of larvae. Circulation in the North Sea is pre-dominantly wind-driven during the winter, and in 1987-1988 anomalous atmospheric conditions caused a reduction in cyclonic circulation and unusual transport of larvae from northern North Sea and west of Scotland spawning areas. Predicting variations in recruitment in advance of fishery legislation has always been difficult and the collapse of North Sea herring populations during the mid-1970s is believed to have been due to a period of several years of low recruitment coupled with high fishing activity2. Our results suggest that a better understanding can be achieved with the aid of environmental modelling.

  4. Mass loss from advective accretion disc around rotating black holes

    CERN Document Server

    Aktar, Ramiz; Nandi, Anuj

    2015-01-01

    We examine the properties of the outflowing matter from an advective accretion disc around a spinning black hole. During accretion, rotating matter experiences centrifugal pressure supported shock transition that effectively produces a virtual barrier around the black hole in the form of post-shock corona (hereafter, PSC). Due to shock compression, PSC becomes hot and dense that eventually deflects a part of the inflowing matter as bipolar outflows because of the presence of extra thermal gradient force. In our approach, we study the outflow properties in terms of the inflow parameters, namely specific energy (${\\mathcal E}$) and specific angular momentum ($\\lambda$) considering the realistic outflow geometry around the rotating black holes. We find that spin of the black hole ($a_k$) plays an important role in deciding the outflow rate $R_{\\dot m}$ (ratio of mass flux of outflow and inflow), in particular, $R_{\\dot m}$ is directly correlated with $a_k$ for the same set of inflow parameters. It is found that ...

  5. Population persistence under advection-diffusion in river networks.

    Science.gov (United States)

    Ramirez, Jorge M

    2012-11-01

    An integro-differential equation on a tree graph is used to model the time evolution and spatial distribution of a population of organisms in a river network. Individual organisms become mobile at a constant rate, and disperse according to an advection-diffusion process with coefficients that are constant on the edges of the graph. Appropriate boundary conditions are imposed at the outlet and upstream nodes of the river network. The local rates of population growth/decay and that by which the organisms become mobile, are assumed constant in time and space. Imminent extinction of the population is understood as the situation whereby the zero solution to the integro-differential equation is stable. Lower and upper bounds for the eigenvalues of the dispersion operator, and related Sturm-Liouville problems are found. The analysis yields sufficient conditions for imminent extinction and/or persistence in terms of the values of water velocity, channel length, cross-sectional area and diffusivity throughout the river network.

  6. Riemannian manifolds as Lie-Rinehart algebras

    Science.gov (United States)

    Pessers, Victor; van der Veken, Joeri

    2016-07-01

    In this paper, we show how Lie-Rinehart algebras can be applied to unify and generalize the elementary theory of Riemannian geometry. We will first review some necessary theory on a.o. modules, bilinear forms and derivations. We will then translate some classical theory on Riemannian geometry to the setting of Rinehart spaces, a special kind of Lie-Rinehart algebras. Some generalized versions of classical results will be obtained, such as the existence of a unique Levi-Civita connection, inducing a Levi-Civita connection on a submanifold, and the construction of spaces with constant sectional curvature.

  7. Split-octonion Lie 3-algebra

    CERN Document Server

    Jardino, Sergio

    2010-01-01

    We extend the concept of a generalized Lie 3-algebra, known to octonions $\\mathbb{O}$, to split-octonions $\\mathbb{SO}$. In order to do that, we introduce a notational device that unifies the two elements product of both of the algebras. We have also proved that $\\mathbb{SO}$ is a Malcev algebra and have recalculated known relations for the structure constants in terms of the introduced structure tensor. An application of the split Lie $3-$algebra to a Bagger and Lambert gauge theory is also discussed.

  8. Integrability of Lie Systems Through Riccati Equations

    Science.gov (United States)

    Cariñena, José F.; de Lucas, Javier

    Integrability conditions for Lie systems are related to reduction or transformation processes. We here analyse a geometric method to construct integrability conditions for Riccati equations following these approaches. This approach provides us with a unified geometrical viewpoint that allows us to analyse some previous works on the topic and explain new properties. Moreover, this new approach can be straightforwardly generalised to describe integrability conditions for any Lie system. Finally, we show the usefulness of our treatment in order to study the problem of the linearisability of Riccati equations.

  9. Integrability of Lie systems through Riccati equations

    CERN Document Server

    Cariñena, José F

    2010-01-01

    Integrability conditions for Lie systems are related to reduction or transformation processes. We here analyse a geometric method to construct integrability conditions for Riccati equations following these approaches. This approach provides us with a unified geometrical viewpoint that allows us to analyse some previous works on the topic and explain new properties. Moreover, this new approach can be straightforwardly generalised to describe integrability conditions for any Lie system. Finally, we show the usefulness of our treatment in order to study the problem of the linearisability of Riccati equations.

  10. Quiver Gauge theories from Lie Superalgebras

    CERN Document Server

    Belhaj, A

    2012-01-01

    We discuss quiver gauge models with matter fields based on Dynkin diagrams of Lie superalgebra structures. We focus on A(1,0) case and we find first that it can be related to intersecting complex cycles with genus $g$. Using toric geometry, A(1,0) quivers are analyzed in some details and it is shown that A(1,0) can be used to incorporate fundamental fields to a product of two unitary factor groups. We expect that this approach can be applied to other kinds of Lie superalgebras;

  11. Spiders for rank 2 Lie algebras

    CERN Document Server

    Kuperberg, G

    1996-01-01

    A spider is an axiomatization of the representation theory of a group, quantum group, Lie algebra, or other group or group-like object. We define certain combinatorial spiders by generators and relations that are isomorphic to the representation theories of the three rank two simple Lie algebras, namely A2, B2, and G2. They generalize the widely-used Temperley-Lieb spider for A1. Among other things, they yield bases for invariant spaces which are probably related to Lusztig's canonical bases, and they are useful for computing quantities such as generalized 6j-symbols and quantum link invariants.

  12. Lie algebra contractions and separation of variables

    CERN Document Server

    Vinternits, P; Pogosyan, G S; Sissakian, A N

    2001-01-01

    The concept of analytical Lie group contractions is introduced to relate the separation of variables in space of constant nonzero curvature to separation in Euclidean or pseudo-Euclidean spaces. The contraction parameter is introduced explicitly into the basis of the Lie algebra, the Laplace-Beltrami operator, the complete set of commuting operators, the coordinates themselves and into the solutions. This enables to obtain asymptotic formulae connecting special functions related to the groups O(n) and O(n,1) to those related to Euclidean and pseudo-Euclidean groups

  13. Lie Point Symmetries of Differential-Difference Equations

    Institute of Scientific and Technical Information of China (English)

    DING Wei; TANG Xiao-Yan

    2004-01-01

    In this paper, the classical Lie group approach is extended to find some Lie point symmetries of differentialdifference equations. It reveals that the obtained Lie point symmetries can constitute a Kac-Moody-Virasoro algebra.

  14. Generalized double extension and descriptions of qadratic Lie superalgebras

    CERN Document Server

    Bajo, I; Bordemann, M

    2007-01-01

    A Lie superalgebra endowed with a supersymmetric, even, non-degenerate, invariant bilinear form is called a quadratic Lie superalgebra. In this paper we give inductive descriptions of quadratic Lie superalgebras in terms of generalized double extensions.

  15. The discrete Feynman integral

    NARCIS (Netherlands)

    Dorlas, T. C.; Thomas, E. G. F.

    2008-01-01

    We construct a genuine Radon measure with values in B(l(2)(Z(d))) on the set of paths in Z(d) representing Feynman's integral for the discrete Laplacian on l(2)(Z(d)), and we prove the Feynman integral formula for the solutions of the Schrodinger equation with Hamiltonian H=-1/2 Delta+ V, where Delt

  16. Discrete time process algebra

    NARCIS (Netherlands)

    Bergstra, J.A.; Baeten, J.C.M.

    1996-01-01

    The axiom system ACP of [BeK84a] was extended with real time features in [BaB91]. Here we proceed to define a discrete time extension of ACP, along the lines of ATP [NiS94]. We present versions based on relative timing and on absolute timing. Both approaches are integrated using parametric timing. T

  17. Discrete gauge theories

    NARCIS (Netherlands)

    de Wild Propitius, M.D.F.; Bais, F.A.

    1999-01-01

    In these lectures, we present a self-contained treatment of planar gauge theories broken down to some finite residual gauge group $H$ via the Higgs mechanism. The main focus is on the discrete $H$ gauge theory describing the long distance physics of such a model. The spectrum features global $H$ cha

  18. The Lie Algebras in which Every Subspace s Its Subalgebra

    Institute of Scientific and Technical Information of China (English)

    WU MING-ZHONG

    2009-01-01

    In this paper, we study the Lie algebras in which every subspace is its subalgebra (denoted by HB Lie algebras). We get that a nonabelian Lie algebra is an HB Lie algebra if and only if it is isomorphic to g+Cidg, where g is an abelian Lie algebra. Moreover we show that the derivation algebra and the holomorph of a nonabelian HB Lie algebra are complete.

  19. Lie, truth, lie: the role of task switching in a deception context.

    Science.gov (United States)

    Debey, Evelyne; Liefooghe, Baptist; De Houwer, Jan; Verschuere, Bruno

    2015-05-01

    A cornerstone of the task switching literature is the finding that task performance is typically slower and more error-prone when the task switches than when it repeats. So far, deception research has largely ignored that such cognitive switch costs should also emerge when switching between truth telling and lying, and may affect the cognitive cost of lying as reflected in higher prefrontal brain activity and slower and less accurate responding compared to truth telling. To get a grasp on the relative size of the switch costs associated with lying and truth telling, the current study had participants perform a reaction time-based deception task, in which they alternated between lying and telling the truth to yes/no questions that were related to activities performed in the lab (Experiment 1) or neutral autobiographical facts (Experiment 2). In both experiments, the error and reaction time switch costs were found to be equally large for switching from truth telling to lying and from lying to truth telling. This symmetry in switch costs can be explained from the hypothesis that lying requires a first step of truth telling, and demonstrates that task switching does not contribute to the cognitive cost of lying when the repetition/switch ratio is balanced. Theoretical and methodological implications are considered.

  20. Lying in Business : Insights from Hannah Arendt’s ‘Lying in Politics’

    NARCIS (Netherlands)

    Eenkhoorn, P.; Graafland, J.J.

    2010-01-01

    The famous political philosopher Hannah Arendt develops several arguments why truthfulness cannot be counted among the political virtues. This article shows that similar arguments apply to lying in business. Based on Hannah Arendt’s theory, we distinguish five reasons why lying is a structural tempt

  1. Teaching the Truth about Lies to Psychology Students: The Speed Lying Task

    Science.gov (United States)

    Pearson, Matthew R.; Richardson, Thomas A.

    2013-01-01

    To teach the importance of deception in everyday social life, an in-class activity called the "Speed Lying Task" was given in an introductory social psychology class. In class, two major research findings were replicated: Individuals detected deception at levels no better than expected by chance and lie detection confidence was unrelated…

  2. Lying in Business : Insights from Hannah Arendt’s ‘Lying in Politics’

    NARCIS (Netherlands)

    Eenkhoorn, P.; Graafland, J.J.

    2010-01-01

    The famous political philosopher Hannah Arendt develops several arguments why truthfulness cannot be counted among the political virtues. This article shows that similar arguments apply to lying in business. Based on Hannah Arendt’s theory, we distinguish five reasons why lying is a structural tempt

  3. Lying in Business : Insights from Hannah Arendt’s ‘Lying in Politics’

    NARCIS (Netherlands)

    Eenkhoorn, P.; Graafland, J.J.

    2010-01-01

    The famous political philosopher Hannah Arendt develops several arguments why truthfulness cannot be counted among the political virtues. This article shows that similar arguments apply to lying in business. Based on Hannah Arendt’s theory, we distinguish five reasons why lying is a structural

  4. Teaching the Truth about Lies to Psychology Students: The Speed Lying Task

    Science.gov (United States)

    Pearson, Matthew R.; Richardson, Thomas A.

    2013-01-01

    To teach the importance of deception in everyday social life, an in-class activity called the "Speed Lying Task" was given in an introductory social psychology class. In class, two major research findings were replicated: Individuals detected deception at levels no better than expected by chance and lie detection confidence was unrelated…

  5. Why Do Lie-Catchers Fail? A Lens Model Meta-Analysis of Human Lie Judgments

    Science.gov (United States)

    Hartwig, Maria; Bond, Charles F., Jr.

    2011-01-01

    Decades of research has shown that people are poor at detecting lies. Two explanations for this finding have been proposed. First, it has been suggested that lie detection is inaccurate because people rely on invalid cues when judging deception. Second, it has been suggested that lack of valid cues to deception limits accuracy. A series of 4…

  6. Yang-Baxter Maps, Discrete Integrable Equations and Quantum Groups

    CERN Document Server

    Bazhanov, Vladimir V

    2015-01-01

    For every quantized Lie algebra there exists a map from the tensor square of the algebra to itself, which by construction satisfies the set-theoretic Yang-Baxter equation. This map allows one to define an integrable discrete quantum evolution system on quadrilateral lattices, where local degrees of freedom (dynamical variables) take values in a tensor power of the quantized Lie algebra. The corresponding equations of motion admit the zero curvature representation. The commuting Integrals of Motion are defined in the standard way via the Quantum Inverse Problem Method, utilizing Baxter's famous commuting transfer matrix approach. All elements of the above construction have a meaningful quasi-classical limit. As a result one obtains an integrable discrete Hamiltonian evolution system, where the local equation of motion are determined by a classical Yang-Baxter map and the action functional is determined by the quasi-classical asymptotics of the universal R-matrix of the underlying quantum algebra. In this paper...

  7. Hiding an Inconvenient Truth : Lies and Vagueness

    NARCIS (Netherlands)

    Serra Garcia, M.; van Damme, E.E.C.; Potters, J.J.M.

    2010-01-01

    When truth conflicts with e¢ ciency, can verbal communication destroy efficiency? Or are lies or vagueness used to hide inconvenient truths? We consider a sequential 2-player public good game in which the leader has private information about the value of the public good. This value can be low, high,

  8. Are 'Lying Compositions' Detrimental To Student Growth?

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ A greater number of primary school students are inventing stories and telling lies when they are supposed to be writing about personal experiences. The Chengdu Business Daily said, of 40 pupils in a grade-four class, 30 wrote about how they struggled with human traffickers or thieves, and 26 pupils admitted they made the stories up.

  9. Lie Algebra of Noncommutative Inhomogeneous Hopf Algebra

    CERN Document Server

    Lagraa, M

    1997-01-01

    We construct the vector space dual to the space of right-invariant differential forms construct from a first order differential calculus on inhomogeneous quantum group. We show that this vector space is equipped with a structure of a Hopf algebra which closes on a noncommutative Lie algebra satisfying a Jacobi identity.

  10. SAYD modules over Lie-Hopf algebras

    CERN Document Server

    Rangipour, B

    2011-01-01

    In this paper a general van Est type isomorphism is established. The isomorphism is between the Lie algebra cohomology of a bicrossed sum Lie algebra and the Hopf cyclic cohomology of its Hopf algebra. We first prove a one to one correspondence between stable-anti-Yetter-Drinfeld (SAYD) modules over the total Lie algebra and SAYD modules over the associated Hopf algebra. In contrast to the non-general case done in our previous work, here the van Est isomorphism is found at the first level of a natural spectral sequence, rather than at the level of complexes. It is proved that the Connes-Moscovici Hopf algebras do not admit any finite dimensional SAYD modules except the unique one-dimensional one found by Connes- Moscovici in 1998. This is done by extending our techniques to work with the infinite dimensional Lie algebra of formal vector fields. At the end, the one to one correspondence is applied to construct a highly nontrivial four dimensional SAYD module over the Schwarzian Hopf algebra. We then illustrate...

  11. Happiness lies somewhere in your brain

    Institute of Scientific and Technical Information of China (English)

    梅寒

    2007-01-01

    <正> When I was a kid,I defined happinessas being able to afford anything that was de-sired and thus I came up with the conclusionthat happiness lies in the possession of mon-ey.Time turned me tall and smart,also,able

  12. Lie algebras and linear differential equations.

    Science.gov (United States)

    Brockett, R. W.; Rahimi, A.

    1972-01-01

    Certain symmetry properties possessed by the solutions of linear differential equations are examined. For this purpose, some basic ideas from the theory of finite dimensional linear systems are used together with the work of Wei and Norman on the use of Lie algebraic methods in differential equation theory.

  13. On Split Lie Triple Systems II

    Indian Academy of Sciences (India)

    Antonio J Calderón Martín; M Forero Piulestán

    2010-04-01

    In [4] it is studied that the structure of split Lie triple systems with a coherent 0-root space, that is, satisfying $[T_0,T_0,T]=0$ and $[T_0,T_,T_0]≠ 0$ for any nonzero root and where $T_0$ denotes the 0-root space and $T_$ the -root space, by showing that any of such triple systems with a symmetric root system is of the form $T=\\mathcal{U}+\\sum_j I_j$ with $\\mathcal{U}$ a subspace of the 0-root space $T_0$ and any $I_j$ a well described ideal of , satisfying $[I_j,T,I_k]=0$ if $j≠ k$. It is also shown in [4] that under certain conditions, a split Lie triple system with a coherent 0-root space is the direct sum of the family of its minimal ideals, each one being a simple split Lie triple system, and the simplicity of is characterized. In the present paper we extend these results to arbitrary split Lie triple systems with no restrictions on their 0-root spaces.

  14. SAYD Modules over Lie-Hopf Algebras

    Science.gov (United States)

    Rangipour, Bahram; Sütlü, Serkan

    2012-11-01

    In this paper a general van Est type isomorphism is proved. The isomorphism is between the Lie algebra cohomology of a bicrossed sum Lie algebra and the Hopf cyclic cohomology of its Hopf algebra. We first prove a one to one correspondence between stable-anti-Yetter-Drinfeld (SAYD) modules over the total Lie algebra and those modules over the associated Hopf algebra. In contrast to the non-general case done in our previous work, here the van Est isomorphism is proved at the first level of a natural spectral sequence, rather than at the level of complexes. It is proved that the Connes-Moscovici Hopf algebras do not admit any finite dimensional SAYD modules except the unique one-dimensional one found by Connes-Moscovici in 1998. This is done by extending our techniques to work with the infinite dimensional Lie algebra of formal vector fields. At the end, the one to one correspondence is applied to construct a highly nontrivial four dimensional SAYD module over the Schwarzian Hopf algebra. We then illustrate the whole theory on this example. Finally explicit representative cocycles of the cohomology classes for this example are calculated.

  15. Verification of Advective Bar Elements Implemented in the Aria Thermal Response Code.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Brantley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    A verification effort was undertaken to evaluate the implementation of the new advective bar capability in the Aria thermal response code. Several approaches to the verification process were taken : a mesh refinement study to demonstrate solution convergence in the fluid and the solid, visually examining the mapping of the advective bar element nodes to the surrounding surfaces, and a comparison of solutions produced using the advective bars for simple geometries with solutions from commercial CFD software . The mesh refinement study has shown solution convergence for simple pipe flow in both temperature and velocity . Guidelines were provided to achieve appropriate meshes between the advective bar elements and the surrounding volume. Simulations of pipe flow using advective bars elements in Aria have been compared to simulations using the commercial CFD software ANSYS Fluent (r) and provided comparable solutions in temperature and velocity supporting proper implementation of the new capability. Verification of Advective Bar Elements iv Acknowledgements A special thanks goes to Dean Dobranich for his guidance and expertise through all stages of this effort . His advice and feedback was instrumental to its completion. Thanks also goes to Sam Subia and Tolu Okusanya for helping to plan many of the verification activities performed in this document. Thank you to Sam, Justin Lamb and Victor Brunini for their assistance in resolving issues encountered with running the advective bar element model. Finally, thanks goes to Dean, Sam, and Adam Hetzler for reviewing the document and providing very valuable comments.

  16. Symmetries of the Continuous and Discrete Krichever-Novikov Equation

    Directory of Open Access Journals (Sweden)

    Decio Levi

    2011-10-01

    Full Text Available A symmetry classification is performed for a class of differential-difference equations depending on 9 parameters. A 6-parameter subclass of these equations is an integrable discretization of the Krichever-Novikov equation. The dimension n of the Lie point symmetry algebra satisfies 1≤n≤5. The highest dimensions, namely n=5 and n=4 occur only in the integrable cases.

  17. STANDING SHOCK INSTABILITY IN ADVECTION-DOMINATED ACCRETION FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Le, Truong [Department of Physics, Astronomy and Geology, Berry College, Mount Berry, GA 30149 (United States); Wood, Kent S.; Wolff, Michael T. [High Energy Space Environment Branch, Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Becker, Peter A. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Putney, Joy, E-mail: tle@berry.edu [Department of Physics and Engineering, Washington and Lee University, Lexington, VA 24450 (United States)

    2016-03-10

    Depending on the values of the energy and angular momentum per unit mass in the gas supplied at large radii, inviscid advection-dominated accretion flows can display velocity profiles with either preshock deceleration or preshock acceleration. Nakayama has shown that these two types of flow configurations are expected to have different stability properties. By employing the Chevalier and Imamura linearization method and the Nakayama instability boundary conditions, we discover that there are regions of parameter space where disks/shocks with outflows can be stable or unstable. In regions of instability, we find that preshock deceleration is always unstable to the zeroth mode with zero frequency of oscillation, but is always stable to the fundamental mode and overtones. Furthermore, we also find that preshock acceleration is always unstable to the zeroth mode and that the fundamental mode and overtones become increasingly less stable as the shock location moves away from the horizon when the disk half-height expands above ∼12 gravitational radii at the shock radius. In regions of stability, we demonstrate the zeroth mode to be stable for the velocity profiles that exhibit preshock acceleration and deceleration. Moreover, for models that are linearly unstable, our model suggests the possible existence of quasi-periodic oscillations (QPOs) with ratios 2:3 and 3:5. These ratios are believed to occur in stellar and supermassive black hole candidates, for example, in GRS 1915+105 and Sgr A*, respectively. We expect that similar QPO ratios also exist in regions of stable shocks.

  18. Round window membrane intracochlear drug delivery enhanced by induced advection.

    Science.gov (United States)

    Borkholder, David A; Zhu, Xiaoxia; Frisina, Robert D

    2014-01-28

    Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy+canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds.

  19. The contiguous domains of Arctic Ocean advection: Trails of life and death

    Science.gov (United States)

    Wassmann, P.; Kosobokova, K. N.; Slagstad, D.; Drinkwater, K. F.; Hopcroft, R. R.; Moore, S. E.; Ellingsen, I.; Nelson, R. J.; Carmack, E.; Popova, E.; Berge, J.

    2015-12-01

    The central Arctic Ocean is not isolated, but tightly connected to the northern Pacific and Atlantic Oceans. Advection of nutrient-, detritus- and plankton-rich waters into the Arctic Ocean forms lengthy contiguous domains that connect subarctic with the arctic biota, supporting both primary production and higher trophic level consumers. In turn, the Arctic influences the physical, chemical and biological oceanography of adjacent subarctic waters through southward fluxes. However, exports of biomass out of the Arctic Ocean into both the Pacific and Atlantic Oceans are thought to be far smaller than the northward influx. Thus, Arctic Ocean ecosystems are net biomass beneficiaries through advection. The biotic impact of Atlantic- and Pacific-origin taxa in arctic waters depends on the total supply of allochthonously-produced biomass, their ability to survive as adults and their (unsuccessful) reproduction in the new environment. Thus, advective transport can be thought of as trails of life and death in the Arctic Ocean. Through direct and indirect (mammal stomachs, models) observations this overview presents information about the advection and fate of zooplankton in the Arctic Ocean, now and in the future. The main zooplankton organisms subjected to advection into and inside the Arctic Ocean are (a) oceanic expatriates of boreal Atlantic and Pacific origin, (b) oceanic Arctic residents and (c) neritic Arctic expatriates. As compared to the Pacific gateway the advective supply of zooplankton biomass through the Atlantic gateways is 2-3 times higher. Advection characterises how the main planktonic organisms interact along the contiguous domains and shows how the subarctic production regimes fuel life in the Arctic Ocean. The main differences in the advective regimes through the Pacific and Atlantic gateways are presented. The Arctic Ocean is, at least in some regions, a net heterotrophic ocean that - during the foreseeable global warming trend - will more and more rely

  20. Comments on the newly discovered advection dominated flows around black holes and neutron stars

    CERN Document Server

    Chakrabarti, S K

    1995-01-01

    We provide complete and global solutions of transonic flows around black holes, in presence of advection, rotation, heating and cooling. We show that for any degree of advection, there may exist two critical viscosity parameters \\alpha_{c1, c2} such that for \\alpha \\alpha_{c2}, the flow may again pass through the inner sonic point, depending on flow parameters. No new topologies emerge other than what we found earlier while studying viscous isothermal transonic flows. These findings indicate that the newly discovered advection dominated flows do not constitute any new solutions.

  1. Advective and diffusive contributions to reactive gas transport during pyrite oxidation in the unsaturated zone

    DEFF Research Database (Denmark)

    Binning, Philip John; Postma, Diederik Jan; Russel, T.F.;

    2007-01-01

    at depth in the unsaturated zone, a pressure gradient is created between the reactive zone and the ground surface, causing a substantial advective air flow into the subsurface. To determine the balance between advective and diffusive transport, a one-dimensional multicomponent unsaturated zone gas...... flows at steady state. However, greater pressure gradients are found in low-permeability soils. In transient cases, advective fluxes depend on the initial conditions and can be far greater than diffusive fluxes. In contrast to steady state conditions the transient case is sensitive to other model...

  2. The effect of magnetic resistivity in advection dominated accretion disk with poloidal magnetic

    Directory of Open Access Journals (Sweden)

    J Ghanbari

    2009-12-01

    Full Text Available In this work, we carry out self –similar solutions of viscous-resistive accretion flows around a magnetized compact object. We consider an axi-symmetric, rotating, isothermal steady accretion flow, which contains a poloidal magnetic field of the central star. The dominant mechanism of energy dissipation is assumed to be the turbulence viscosity and magnetic diffusivity due to the magnetic field of the central star. We explore the effect of viscosity, magnetic diffusivity and advection on a rotating disk. We show that dynamical quantities of advection dominated accretion flows (ADAFs are sensitive to the advection, viscosity and magnetic diffusivity parameters.

  3. Tomography-based monitoring of isothermal snow metamorphism under advective conditions

    Directory of Open Access Journals (Sweden)

    P. P. Ebner

    2015-02-01

    Full Text Available Time-lapse X-ray micro-tomography was used to investigate the structural dynamics of isothermal snow metamorphism exposed to an advective airflow. Diffusion and advection across the snow pores were analysed in controlled laboratory experiments. The 3-D digital geometry obtained by tomographic scans was used in direct pore-level numerical simulations to determine the effective transport properties. The results showed that isothermal advection with saturated air have no influence on the coarsening rate that is typical for isothermal snow metamorphism. Diffusion originating in the Kelvin effect between snow structures dominates and is the main transport process in isothermal snow packs.

  4. SEBAL-A: A remote sensing ET algorithm that accounts for advection with limited data. Part II: Test for transferability

    Science.gov (United States)

    Because the Surface Energy Balance Algorithm for Land (SEBAL) tends to underestimate ET under conditions of advection, the model was modified by incorporating an advection component as part of the energy usable for crop evapotranspiration (ET). The modification involved the estimation of advected en...

  5. Discrete mathematics with applications

    CERN Document Server

    Koshy, Thomas

    2003-01-01

    This approachable text studies discrete objects and the relationsips that bind them. It helps students understand and apply the power of discrete math to digital computer systems and other modern applications. It provides excellent preparation for courses in linear algebra, number theory, and modern/abstract algebra and for computer science courses in data structures, algorithms, programming languages, compilers, databases, and computation.* Covers all recommended topics in a self-contained, comprehensive, and understandable format for students and new professionals * Emphasizes problem-solving techniques, pattern recognition, conjecturing, induction, applications of varying nature, proof techniques, algorithm development and correctness, and numeric computations* Weaves numerous applications into the text* Helps students learn by doing with a wealth of examples and exercises: - 560 examples worked out in detail - More than 3,700 exercises - More than 150 computer assignments - More than 600 writing projects*...

  6. Discrete torsion defects

    CERN Document Server

    Brunner, Ilka; Plencner, Daniel

    2014-01-01

    Orbifolding two-dimensional quantum field theories by a symmetry group can involve a choice of discrete torsion. We apply the general formalism of `orbifolding defects' to study and elucidate discrete torsion for topological field theories. In the case of Landau-Ginzburg models only the bulk sector had been studied previously, and we re-derive all known results. We also introduce the notion of `projective matrix factorisations', show how they naturally describe boundary and defect sectors, and we further illustrate the efficiency of the defect-based approach by explicitly computing RR charges. Roughly half of our results are not restricted to Landau-Ginzburg models but hold more generally, for any topological field theory. In particular we prove that for a pivotal bicategory, any two objects of its orbifold completion that have the same base are orbifold equivalent. Equivalently, from any orbifold theory (including those based on nonabelian groups) the original unorbifolded theory can be be obtained by orbifo...

  7. Discrete dynamical models

    CERN Document Server

    Salinelli, Ernesto

    2014-01-01

    This book provides an introduction to the analysis of discrete dynamical systems. The content is presented by an unitary approach that blends the perspective of mathematical modeling together with the ones of several discipline as Mathematical Analysis, Linear Algebra, Numerical Analysis, Systems Theory and Probability. After a preliminary discussion of several models, the main tools for the study of linear and non-linear scalar dynamical systems are presented, paying particular attention to the stability analysis. Linear difference equations are studied in detail and an elementary introduction of Z and Discrete Fourier Transform is presented. A whole chapter is devoted to the study of bifurcations and chaotic dynamics. One-step vector-valued dynamical systems are the subject of three chapters, where the reader can find the applications to positive systems, Markov chains, networks and search engines. The book is addressed mainly to students in Mathematics, Engineering, Physics, Chemistry, Biology and Economic...

  8. Time Discretization Techniques

    KAUST Repository

    Gottlieb, S.

    2016-10-12

    The time discretization of hyperbolic partial differential equations is typically the evolution of a system of ordinary differential equations obtained by spatial discretization of the original problem. Methods for this time evolution include multistep, multistage, or multiderivative methods, as well as a combination of these approaches. The time step constraint is mainly a result of the absolute stability requirement, as well as additional conditions that mimic physical properties of the solution, such as positivity or total variation stability. These conditions may be required for stability when the solution develops shocks or sharp gradients. This chapter contains a review of some of the methods historically used for the evolution of hyperbolic PDEs, as well as cutting edge methods that are now commonly used.

  9. Linearity stabilizes discrete breathers

    Indian Academy of Sciences (India)

    T R Krishna Mohan; Surajit Sen

    2011-11-01

    The study of the dynamics of 1D chains with both harmonic and nonlinear interactions, as in the Fermi–Pasta–Ulam (FPU) and related problems, has played a central role in efforts to identify the broad consequences of nonlinearity in these systems. Here we study the dynamics of highly localized excitations, or discrete breathers, which are known to be initiated by the quasistatic stretching of bonds between adjacent particles. We show via dynamical simulations that acoustic waves introduced by the harmonic term stabilize the discrete breather by suppressing the breather’s tendency to delocalize and disperse. We conclude that the harmonic term, and hence acoustic waves, are essential for the existence of localized breathers in these systems.

  10. Lectures on discrete geometry

    CERN Document Server

    2002-01-01

    Discrete geometry investigates combinatorial properties of configurations of geometric objects. To a working mathematician or computer scientist, it offers sophisticated results and techniques of great diversity and it is a foundation for fields such as computational geometry or combinatorial optimization. This book is primarily a textbook introduction to various areas of discrete geometry. In each area, it explains several key results and methods, in an accessible and concrete manner. It also contains more advanced material in separate sections and thus it can serve as a collection of surveys in several narrower subfields. The main topics include: basics on convex sets, convex polytopes, and hyperplane arrangements; combinatorial complexity of geometric configurations; intersection patterns and transversals of convex sets; geometric Ramsey-type results; polyhedral combinatorics and high-dimensional convexity; and lastly, embeddings of finite metric spaces into normed spaces. Jiri Matousek is Professor of Com...

  11. Steerable Discrete Cosine Transform

    OpenAIRE

    Fracastoro, Giulia; Fosson, Sophie; Magli, Enrico

    2017-01-01

    In image compression, classical block-based separable transforms tend to be inefficient when image blocks contain arbitrarily shaped discontinuities. For this reason, transforms incorporating directional information are an appealing alternative. In this paper, we propose a new approach to this problem, namely, a discrete cosine transform (DCT) that can be steered in any chosen direction. Such transform, called steerable DCT (SDCT), allows to rotate in a flexible way pairs of basis vectors, an...

  12. Discrete Quantum Mechanics

    OpenAIRE

    Odake, Satoru; Sasaki, Ryu

    2011-01-01

    A comprehensive review of the discrete quantum mechanics with the pure imaginary shifts and the real shifts is presented in parallel with the corresponding results in the ordinary quantum mechanics. The main subjects to be covered are the factorised Hamiltonians, the general structure of the solution spaces of the Schroedinger equation (Crum's theorem and its modification), the shape invariance, the exact solvability in the Schroedinger picture as well as in the Heisenberg picture, the creati...

  13. Dimension of the $c$-nilpotent multiplier of Lie algebras

    Indian Academy of Sciences (India)

    MEHDI ARASKHAN; MOHAMMAD REZA RISMANCHIAN

    2016-08-01

    The purpose of this paper is to derive some inequalities for dimension of the $c$-nilpotent multiplier of finite dimensional Lie algebras and their factor Lie algebras. We further obtain an inequality between dimensions of $c$-nilpotent multiplier of Lie algebra $L$ and tensor product of a central ideal by its abelianized factor Lie algebra

  14. Legitimate lies : The relationship between omission, commission, and cheating

    NARCIS (Netherlands)

    Pittarello, Andrea; Rubaltelli, Enrico; Motro, Daphna

    2016-01-01

    Across four experiments, we show that when people can serve their self-interest, they are more likely to refrain from reporting the truth ( lie of omission) than actively lie ( lie of commission). We developed a novel online "Heads or Tails" task in which participants can lie to win a monetary prize

  15. Whittaker categories and strongly typical Whittaker modules for Lie superalgebras

    CERN Document Server

    Bagci, Irfan; Wiesner, Emilie

    2012-01-01

    Following analogous constructions for Lie algebras, we define Whittaker modules and Whittaker categories for finite-dimensional simple Lie superalgebras. Results include a decomposition of Whittaker categories for a Lie superalgebra according to the action of an appropriate sub-superalgebra; and, for basic classical Lie superalgebras of type I, a description of the strongly typical simple Whittaker modules.

  16. A Local Characterization of Lie Homomorphisms of Nest Algebras

    Institute of Scientific and Technical Information of China (English)

    YANG Miao-xia; ZHANG Jian-hua

    2014-01-01

    In this paper, linear maps preserving Lie products at zero points on nest algebras are studied. It is proved that every linear map preserving Lie products at zero points on any finite nest algebra is a Lie homomorphism. As an application, the form of a linear bijection preserving Lie products at zero points between two finite nest algebras is obtained.

  17. Lie symmetries for equations in conformal geometries

    CERN Document Server

    Hansraj, S; Msomi, A M; Govinder, K S

    2005-01-01

    We seek exact solutions to the Einstein field equations which arise when two spacetime geometries are conformally related. Whilst this is a simple method to generate new solutions to the field equations, very few such examples have been found in practice. We use the method of Lie analysis of differential equations to obtain new group invariant solutions to conformally related Petrov type D spacetimes. Four cases arise depending on the nature of the Lie symmetry generator. In three cases we are in a position to solve the master field equation in terms of elementary functions. In the fourth case special solutions in terms of Bessel functions are obtained. These solutions contain known models as special cases.

  18. Geodesic models generated by Lie symmetries

    CERN Document Server

    Abebe, G Z; Govinder, K S

    2014-01-01

    We study the junction condition relating the pressure to the heat flux at the boundary of a shearing and expanding spherically symmetric radiating star when the fluid particles are travelling in geodesic motion. The Lie symmetry generators that leave the junction condition invariant are identified and the optimal system is generated. We use each element of the optimal system to transform the partial differential equation to an ordinary differential equation. New exact solutions, which are group invariant under the action of Lie point infinitesimal symmetries, are found. We obtain families of traveling wave solutions and self-similar solutions, amongst others. The gravitational potentials are given in terms of elementary functions, and the line elements can be given explicitly in all cases. We show that the Friedmann dust model is regained as a special case, and we can connect our results to earlier investigations.

  19. Analytic factorization of Lie group representations

    DEFF Research Database (Denmark)

    Gimperlein, Heiko; Krötz, Bernhard; Lienau, Christoph

    2012-01-01

    For every moderate growth representation (p,E)(p,E) of a real Lie group G on a Fréchet space, we prove a factorization theorem of Dixmier–Malliavin type for the space of analytic vectors E¿E¿. There exists a natural algebra of superexponentially decreasing analytic functions A(G)A(G), such that E......¿=¿(A(G))E¿E¿=¿(A(G))E¿. As a corollary we obtain that E¿E¿ coincides with the space of analytic vectors for the Laplace–Beltrami operator on G.......For every moderate growth representation (p,E)(p,E) of a real Lie group G on a Fréchet space, we prove a factorization theorem of Dixmier–Malliavin type for the space of analytic vectors E¿E¿. There exists a natural algebra of superexponentially decreasing analytic functions A(G)A(G), such that E...

  20. Harmonic analysis on exponential solvable Lie groups

    CERN Document Server

    Fujiwara, Hidenori

    2015-01-01

    This book is the first one that brings together recent results on the harmonic analysis of exponential solvable Lie groups. There still are many interesting open problems, and the book contributes to the future progress of this research field. As well, various related topics are presented to motivate young researchers. The orbit method invented by Kirillov is applied to study basic problems in the analysis on exponential solvable Lie groups. This method tells us that the unitary dual of these groups is realized as the space of their coadjoint orbits. This fact is established using the Mackey theory for induced representations, and that mechanism is explained first. One of the fundamental problems in the representation theory is the irreducible decomposition of induced or restricted representations. Therefore, these decompositions are studied in detail before proceeding to various related problems: the multiplicity formula, Plancherel formulas, intertwining operators, Frobenius reciprocity, and associated alge...

  1. Constructions of Lie algebras and their modules

    CERN Document Server

    Seligman, George B

    1988-01-01

    This book deals with central simple Lie algebras over arbitrary fields of characteristic zero. It aims to give constructions of the algebras and their finite-dimensional modules in terms that are rational with respect to the given ground field. All isotropic algebras with non-reduced relative root systems are treated, along with classical anisotropic algebras. The latter are treated by what seems to be a novel device, namely by studying certain modules for isotropic classical algebras in which they are embedded. In this development, symmetric powers of central simple associative algebras, along with generalized even Clifford algebras of involutorial algebras, play central roles. Considerable attention is given to exceptional algebras. The pace is that of a rather expansive research monograph. The reader who has at hand a standard introductory text on Lie algebras, such as Jacobson or Humphreys, should be in a position to understand the results. More technical matters arise in some of the detailed arguments. T...

  2. ON THE PRIMARY DECOMPOSITION THEOREM OF MODULAR LIE SUPERALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    CHEN LIANGYUN; MENG DAOJI

    2005-01-01

    This gives some identities of associative Lie superalgebras and some properties of modular Lie superalgebras. Furthermore, the primry decomposition theorem of modular Lie superalgebras is shown. It is well known that the primary decomposition theorem of modular Lie algebras has played an important role in the classification of the finite-dimensional simple modular Lie algebras (see [5, 6]). Analogously, the primary decomposition theorem of modular Lie superalgebras may play an important role in the open classification of the finite dimensional simple modular Lie superalgebras.

  3. Abstract Lie groups and locally compact topological groups

    Directory of Open Access Journals (Sweden)

    Jacek Lech

    2004-05-01

    Full Text Available We introduce a notion of abstract Lie group by means of the mapping which plays the role of the evolution operator. We show some basic properties of such groups very similar to the fundamentals of the infinite dimensional Lie theory. Next we give remarkable examples of abstract Lie groups which are not necessarily usual Lie groups. In particular, by making use of Yamabe theorem we prove that any locally compact topological group admits the structure of abstract Lie group and that the Lie algebra and the exponential mapping of it coincide with those determined by the Lie group structure.

  4. A Method for Measuring Subcanopy CO2 Advection

    Science.gov (United States)

    Staebler, R. M.; Fitzjarrald, D. R.

    2004-12-01

    Underestimation of nocturnal CO2 respiration under calm conditions remains an unsolved problem at many forest flux stations, and several groups are currently investigating the direct measurement of horizontal advection of CO2. This presentation will describe a systematic, relatively low-cost methodology developed to determine whether horizontal mean transport of CO2 accounts for the missing CO2 at the Harvard Forest (Petersham, MA). This methodology includes the characterization of subcanopy motions, determining the appropriate size of the subcanopy network required to make the measurements, developing a method of integrating the measurements in the vertical, and determining the required averaging time. Measurements were conducted over 4 years and produced data for 310 nights covering all seasons. Subcanopy flows were decoupled from the flows aloft 75% of the time. Conditions conducive to the generation of negative buoyancy near the forest floor, necessary for drainage flows to develop, were given in 92% of all nights. The occurrence of nocturnal drainage flows correlated well with "missing flux" problems ("deficit nights"), prompting us to propose an improvement on the commonly used friction velocity criterion (which requires u* to be larger than some empirical cut-off for the eddy fluxes to be considered credible). The "negative buoyancy forcing fraction", i.e. negative buoyancy as a fraction of the sum of the dynamic driving forces, can be shown to predict deficit nights significantly better than the u* cut-off. The appropriate horizontal size of the network of wind and CO2 sensors at the Harvard Forest was shown to be on the order of 100 m, ensuring that sensors were generally observing coherent processes on this scale or larger and thus displaying some correlation. Horizontal transport of CO2 was found to be restricted to the bottom ~10 m of the forest, facilitating the development of a method of integrating the horizontal CO2 gradients in the vertical

  5. On High-Order Upwind Methods for Advection

    Science.gov (United States)

    Huynh, H. T.

    2017-01-01

    In the fourth installment of the celebrated series of five papers entitled "Towards the ultimate conservative difference scheme", Van Leer (1977) introduced five schemes for advection, the first three are piecewise linear, and the last two, piecewise parabolic. Among the five, scheme I, which is the least accurate, extends with relative ease to systems of equations in multiple dimensions. As a result, it became the most popular and is widely known as the MUSCL scheme (monotone upstream-centered schemes for conservation laws). Schemes III and V have the same accuracy, are the most accurate, and are closely related to current high-order methods. Scheme III uses a piecewise linear approximation that is discontinuous across cells, and can be considered as a precursor of the discontinuous Galerkin methods. Scheme V employs a piecewise quadratic approximation that is, as opposed to the case of scheme III, continuous across cells. This method is the basis for the on-going "active flux scheme" developed by Roe and collaborators. Here, schemes III and V are shown to be equivalent in the sense that they yield identical (reconstructed) solutions, provided the initial condition for scheme III is defined from that of scheme V in a manner dependent on the CFL number. This equivalence is counter intuitive since it is generally believed that piecewise linear and piecewise parabolic methods cannot produce the same solutions due to their different degrees of approximation. The finding also shows a key connection between the approaches of discontinuous and continuous polynomial approximations. In addition to the discussed equivalence, a framework using both projection and interpolation that extends schemes III and V into a single family of high-order schemes is introduced. For these high-order extensions, it is demonstrated via Fourier analysis that schemes with the same number of degrees of freedom ?? per cell, in spite of the different piecewise polynomial degrees, share the same

  6. Boundary value problemfor multidimensional fractional advection-dispersion equation

    Directory of Open Access Journals (Sweden)

    Khasambiev Mokhammad Vakhaevich

    2015-05-01

    authors first considered the boundary value problem for stationary equation for mass transfer in super-diffusion conditions and abnormal advection. Then the solution of the problem is explicitly given. The solution is obtained by the Fourier’s method.The obtained results will be useful in liquid filtration theory in fractal medium and for modeling the temperature variations in the heated bar.

  7. Rigorous upper bounds for fluid and plasma transport due to passive advection

    Energy Technology Data Exchange (ETDEWEB)

    Krommes, J.A.; Smith, R.A.; Kim, C.B.

    1987-07-01

    The formulation of variational principles for transport due to passive advection is described. A detailed account of the work has been published elsewhere. In the present paper, the motivations, philosophy, and implications of the method are briefly discussed. 15 refs.

  8. Simulation of Helical Flow Hydrodynamics in Meanders and Advection-Turbulent Diffusion Using Smoothed Particle Hydrodynamics

    Science.gov (United States)

    Gusti, T. P.; Hertanti, D. R.; Bahsan, E.; Soeryantono, H.

    2013-12-01

    Particle-based numerical methods, such as Smoothed Particle Hydrodynamics (SPH), may be able to simulate some hydrodynamic and morphodynamic behaviors better than grid-based numerical methods. This study simulates hydrodynamics in meanders and advection and turbulent diffusion in straight river channels using Microsoft Excel and Visual Basic. The simulators generate three-dimensional data for hydrodynamics and one-dimensional data for advection-turbulent diffusion. Fluid at rest, sloshing, and helical flow are simulated in the river meanders. Spill loading and step loading are done to simulate concentration patterns associated with advection-turbulent diffusion. Results indicate that helical flow is formed due to disturbance in morphology and particle velocity in the stream and the number of particles does not have a significant effect on the pattern of advection-turbulent diffusion concentration.

  9. Solving the Advection-Diffusion Equations in Biological Contexts using the Cellular Potts Model

    CERN Document Server

    Dan, D; Chen, K; Glazier, J A; Dan, Debasis; Mueller, Chris; Chen, Kun; Glazier, James A.

    2005-01-01

    The Cellular Potts Model (CPM) is a robust, cell-level methodology for simulation of biological tissues and morphogenesis. Both tissue physiology and morphogenesis depend on diffusion of chemical morphogens in the extra-cellular fluid or matrix (ECM). Standard diffusion solvers applied to the cellular potts model use finite difference methods on the underlying CPM lattice. However, these methods produce a diffusing field tied to the underlying lattice, which is inaccurate in many biological situations in which cell or ECM movement causes advection rapid compared to diffusion. Finite difference schemes suffer numerical instabilities solving the resulting advection-diffusion equations. To circumvent these problems we simulate advection-diffusion within the framework of the CPM using off-lattice finite-difference methods. We define a set of generalized fluid particles which detach advection and diffusion from the lattice. Diffusion occurs between neighboring fluid particles by local averaging rules which approxi...

  10. Advective surface velocity in the north west Pacific derived from NOAA AVHRR images

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Akiyama, M.; Okada, Y.; Sugimori, Y.

    Using sequential AVHRR images in November 1983, nearsurface advective velocities are derived in the region Kuroshio south of Japan. For deriving the velocities two methods are used. One is the Method of Cross Correlation (MCC), using image pair...

  11. k-symplectic formalism on Lie algebroids

    Energy Technology Data Exchange (ETDEWEB)

    De Leon, M; De Diego, D Martin [Instituto de Ciencias Matematicas (CSIC-UAM-UC3M-UCM) C/Serrano 123, 28006 Madrid (Spain); Salgado, M; Vilarino, S [Departamento de XeometrIa e TopoloxIa, Facultade de Matematicas, Universidade de Santiago de Compostela, 15782-Santiago de Compostela (Spain)], E-mail: mdeleon@imaff.cfmac.csic.es, E-mail: d.martin@imaff.cfmac.csic.es, E-mail: modesto.salgado@usc.es, E-mail: silvia.vilarino@usc.es

    2009-09-25

    In this paper we introduce a geometric description of Lagrangian and Hamiltonian classical field theories on Lie algebroids in the framework of k-symplectic geometry. We discuss the relation between the Lagrangian and Hamiltonian descriptions through a convenient notion of Legendre transformation. The theory is a natural generalization of the standard one; in addition, other interesting examples are studied, in particular, systems with symmetry and Poisson-sigma models.

  12. How to Lie with Bad Data

    OpenAIRE

    De Veaux, Richard D.; Hand, David J.

    2005-01-01

    As Huff’s landmark book made clear, lying with statistics can be accomplished in many ways. Distorting graphics, manipulating data or using biased samples are just a few of the tried and true methods. Failing to use the correct statistical procedure or failing to check the conditions for when the selected method is appropriate can distort results as well, whether the motives of the analyst are honorable or not. Even when the statistical procedure and motives are correct, bad data can produce ...

  13. Lies, Incentives and Self-confidence

    OpenAIRE

    Maggian, Valeria

    2013-01-01

    The present thesis is composed by three chapters, each of them making contributions to three distinct topics in behavioral Economics. The chapters can thus be read independently from each other. The first chapter concerns an experimental analysis which aim is to examine the development of social preferences with respect to age and how they are related with lying behavior of children. The second chapter investigates the role of reciprocity in exacerbating inefficient and opportunistic behavior...

  14. Spherical functions on affine Lie groups

    CERN Document Server

    Etingof, P; Kirillov, A A; Pavel Etingof; Igor Frenkel; Alexander Kirillov Jr

    1994-01-01

    We show that the space of holomorphic functions of a fixed degree on an affine Lie group which take values in a finite-dimensional representation of this group and are equivariant with respect to (twisted) conjugacy coin- cides with the space of conformal blocks of the Wess-Zumino-Witten conformal field theory on an elliptic curve with punctures, or, equivalently,with the space of states of the Chern-Simons topological field theory in genus 1. This provides a group-theoretic realization of the Segal modular functor for elliptic curves. We also show that the the radial part of the second order Laplace operator on an affine Lie group acting in the space of equivariant functions coincides with the operator defining the Knizhnik-Zamolodchikov connection on conformal blocks on elliptic curves, and its eigenfunctions coincide with the correlation functions of conformal blocks. At the critical value of the degree (minus the dual Coxeter number of the underlying simple Lie algebra) there exist higher order Laplace op...

  15. Influence of advective bio-irrigation on carbon and nitrogen cycling in sandy sediments

    OpenAIRE

    Na, T.; Gribsholt, B.; Galaktionov, O. S.; T. Lee; Meysman, F. J. R.

    2008-01-01

    In sandy sediments, the burrow ventilation activity of benthic macrofauna can generate substantial advective flows within the sediment surrounding their burrows. Here we investigated the effects of such advective bio-irrigation on carbon and nitrogen cycling in sandy sediments. To this end, we combined a range of complementary experimental and modelling approaches in a microcosm study of the lugworm Arenicola marina (Polychaeta: Annelida). Bio-irrigation rates were determined using uranine as...

  16. Wright functions governed by fractional directional derivatives and fractional advection diffusion equations

    CERN Document Server

    D'Ovidio, Mirko

    2012-01-01

    We consider fractional directional derivatives and establish some connection with stable densities. Solutions to advection equations involving fractional directional derivatives are presented and some properties investigated. In particular we obtain solutions written in terms of Wright functions by exploiting operational rules involving the shift operator. We also consider fractional advection diffusion equations involving fractional powers of the negative Laplace operator and directional derivatives of fractional order and discuss the probabilistic interpretations of solutions.

  17. Tomography-based monitoring of isothermal snow metamorphism under advective conditions

    OpenAIRE

    P. P. Ebner; M. Schneebeli; A. Steinfeld

    2015-01-01

    Time-lapse X-ray microtomography was used to investigate the structural dynamics of isothermal snow metamorphism exposed to an advective airflow. The effect of diffusion and advection across the snow pores on the snow microstructure were analysed in controlled laboratory experiments and possible effects on natural snowpacks discussed. The 3-D digital geometry obtained by tomographic scans was used in direct pore-level numerical simulations to determine the effective permeabi...

  18. COMPLETE LIE ALGEBRAS WITH l-STEP NILPOTENT RADICALS

    Institute of Scientific and Technical Information of China (English)

    高永存; 孟道冀

    2002-01-01

    The authors first give a necessary and sufficient condition for some solvable Lie algebras with l-step nilpotent radicals to be complete, and then construct a new class of infinite dimensional complete Lie algebras by using the modules of simple Lie algebras. The quotient algebras of this new constructed Lie algebras are non-solvable complete Lie algebras with l-step nilpotent radicals.

  19. Lie algebras with given properties of subalgebras and elements

    CERN Document Server

    Zusmanovich, Pasha

    2011-01-01

    Results about the following classes of finite-dimensional Lie algebras over a field of characteristic zero are presented: anisotropic (i.e., Lie algebras for which each adjoint operator is semisimple), regular (i.e., Lie algebras in which each nonzero element is regular in the sense of Bourbaki), minimal nonabelian (i.e., nonabelian Lie algebras all whose proper subalgebras are abelian), and algebras of depth 2 (i.e., Lie algebras all whose proper subalgebras are abelian or minimal nonabelian).

  20. Classification of filiform Lie algebras of order 3

    Science.gov (United States)

    Navarro, Rosa María

    2016-12-01

    Lie algebras of order 3 constitute a generalization of Lie algebras and superalgebras. Throughout this paper the classification problem of filiform Lie algebras of order 3 is considered and therefore this work is a continuation papers seen in the literature. We approach this classification by extending Vergne's result for filiform Lie algebras and by considering algebras of order 3 of high nilindex. We find the expression of the law to which any elementary filiform Lie algebra of order 3 is isomorphic.

  1. Lie color 代数的商代数%Algebras of quotients of Lie color algebras

    Institute of Scientific and Technical Information of China (English)

    裴凤; 周建华

    2004-01-01

    介绍了Lie color 代数的一些性质,如素性、半素性、非退化性等.给出了Lie color 代数的商代数以及弱商代数的概念,并把Lie color 代数的素性和半素性推广到它的商代数上.利用没有非零零化子的理想对Lie color 代数的商代数进行刻画,证明了:若L是Lie color 代数Q的子代数,则Q是L的商代数当且仅当Q理想吸收于L.通过具体构造证明了每一个半素Lie color 代数都有极大商代数,并给出这个极大商代数的等价刻画.

  2. Discrete epidemic models.

    Science.gov (United States)

    Brauer, Fred; Feng, Zhilan; Castillo-Chavez, Carlos

    2010-01-01

    The mathematical theory of single outbreak epidemic models really began with the work of Kermack and Mackendrick about decades ago. This gave a simple answer to the long-standing question of why epidemics woould appear suddenly and then disappear just as suddenly without having infected an entire population. Therefore it seemed natural to expect that theoreticians would immediately proceed to expand this mathematical framework both because the need to handle recurrent single infectious disease outbreaks has always been a priority for public health officials and because theoreticians often try to push the limits of exiting theories. However, the expansion of the theory via the inclusion of refined epidemiological classifications or through the incorporation of categories that are essential for the evaluation of intervention strategies, in the context of ongoing epidemic outbreaks, did not materialize. It was the global threat posed by SARS in that caused theoreticians to expand the Kermack-McKendrick single-outbreak framework. Most recently, efforts to connect theoretical work to data have exploded as attempts to deal with the threat of emergent and re-emergent diseases including the most recent H1N1 influenza pandemic, have marched to the forefront of our global priorities. Since data are collected and/or reported over discrete units of time, developing single outbreak models that fit collected data naturally is relevant. In this note, we introduce a discrete-epidemic framework and highlight, through our analyses, the similarities between single-outbreak comparable classical continuous-time epidemic models and the discrete-time models introduced in this note. The emphasis is on comparisons driven by expressions for the final epidemic size.

  3. Discrete Dynamics Lab

    Science.gov (United States)

    Wuensche, Andrew

    DDLab is interactive graphics software for creating, visualizing, and analyzing many aspects of Cellular Automata, Random Boolean Networks, and Discrete Dynamical Networks in general and studying their behavior, both from the time-series perspective — space-time patterns, and from the state-space perspective — attractor basins. DDLab is relevant to research, applications, and education in the fields of complexity, self-organization, emergent phenomena, chaos, collision-based computing, neural networks, content addressable memory, genetic regulatory networks, dynamical encryption, generative art and music, and the study of the abstract mathematical/physical/dynamical phenomena in their own right.

  4. Time-Discrete Higher-Order ALE Formulations: Stability

    KAUST Repository

    Bonito, Andrea

    2013-01-01

    Arbitrary Lagrangian Eulerian (ALE) formulations deal with PDEs on deformable domains upon extending the domain velocity from the boundary into the bulk with the purpose of keeping mesh regularity. This arbitrary extension has no effect on the stability of the PDE but may influence that of a discrete scheme. We examine this critical issue for higher-order time stepping without space discretization. We propose time-discrete discontinuous Galerkin (dG) numerical schemes of any order for a time-dependent advection-diffusion-model problem in moving domains, and study their stability properties. The analysis hinges on the validity of the Reynold\\'s identity for dG. Exploiting the variational structure and assuming exact integration, we prove that our conservative and nonconservative dG schemes are equivalent and unconditionally stable. The same results remain true for piecewise polynomial ALE maps of any degree and suitable quadrature that guarantees the validity of the Reynold\\'s identity. This approach generalizes the so-called geometric conservation law to higher-order methods. We also prove that simpler Runge-Kutta-Radau methods of any order are conditionally stable, that is, subject to a mild ALE constraint on the time steps. Numerical experiments corroborate and complement our theoretical results. © 2013 Society for Industrial and Applied Mathematics.

  5. Classification of four-dimensional real Lie bialgebras of symplectic type and their Poisson-Lie groups

    Science.gov (United States)

    Abedi-Fardad, J.; Rezaei-Aghdam, A.; Haghighatdoost, Gh.

    2017-01-01

    We classify all four-dimensional real Lie bialgebras of symplectic type and obtain the classical r-matrices for these Lie bialgebras and Poisson structures on all the associated four-dimensional Poisson-Lie groups. We obtain some new integrable models where a Poisson-Lie group plays the role of the phase space and its dual Lie group plays the role of the symmetry group of the system.

  6. Almost-Riemannian Geometry on Lie Groups

    OpenAIRE

    Ayala, Victor; Jouan, Philippe

    2015-01-01

    A simple Almost-Riemmanian Structure on a Lie group G is defined by a linear vector field and dim(G)-1 left-invariant ones. We state results about the singular locus, the abnormal extremals and the desingularization of such ARS's, and these results are illustrated by examples on the 2D affine and the Heisenberg groups.These ARS's are extended in two ways to homogeneous spaces, and a necessary and sufficient condition for an ARS on a manifold to be equivalent to a general ARS on a homogeneous ...

  7. The graded Lie algebra of general relativity

    CERN Document Server

    Reiterer, Michael

    2014-01-01

    We construct a graded Lie algebra in which a solution to the vacuum Einstein equations is any element of degree 1 whose bracket with itself is zero. Each solution generates a cochain complex, whose first cohomology is linearized gravity about that solution. We gauge-fix to get a smaller cochain complex with the same cohomologies (deformation retraction). The new complex is much smaller, it consists of the solution spaces of linear homogeneous wave equations (symmetric hyperbolic equations). The algorithm that produces these gauges and wave equations is both for linearized gravity and the full Einstein equations. The gauge groupoid is the groupoid of rank 2 complex vector bundles.

  8. Difference Discrete Variational Principle in Discrete Mechanics and Symplectic Algorithm

    Institute of Scientific and Technical Information of China (English)

    LUO Xu-Dong; GUO Han-Ying; LI Yu-Qi; WU Ke

    2004-01-01

    We propose the difference discrete variational principle in discrete mechanics and symplectic algorithmwith variable step-length of time in finite duration based upon a noncommutative differential calculus established inthis paper. This approach keeps both symplecticity and energy conservation discretely. We show that there exists thediscrete version of the Euler-Lagrange cohomology in these discrete systems. We also discuss the solution existencein finite time-length and its site density in continuous limit, and apply our approach to the pendulum with periodicperturbation. The numerical results are satisfactory.

  9. Discrete Exterior Calculus Discretization of Incompressible Navier-Stokes Equations

    KAUST Repository

    Mohamed, Mamdouh S.

    2017-05-23

    A conservative discretization of incompressible Navier-Stokes equations over surface simplicial meshes is developed using discrete exterior calculus (DEC). Numerical experiments for flows over surfaces reveal a second order accuracy for the developed scheme when using structured-triangular meshes, and first order accuracy otherwise. The mimetic character of many of the DEC operators provides exact conservation of both mass and vorticity, in addition to superior kinetic energy conservation. The employment of barycentric Hodge star allows the discretization to admit arbitrary simplicial meshes. The discretization scheme is presented along with various numerical test cases demonstrating its main characteristics.

  10. Calculation of the crack tip opening displacement of a crack lying in a subsurface layer

    Science.gov (United States)

    Higashida, Y.; Kamada, K.

    1985-11-01

    Crack tip opening displacement of a crack lying parallel to a free surface is calculated by counting the number of dislocations emitted into the plastic zone from a crack tip. A discrete dislocation model was used to simulate the crack, while varying the strength of dislocations so as to satisfy the boundary condition. The result coincides numerically with the predictions made in a previous paper, in which the stress intensity factor appearing in a theory of bulk materials was replaced with the one which includes the surface correction.

  11. Poisson hierarchy of discrete strings

    Energy Technology Data Exchange (ETDEWEB)

    Ioannidou, Theodora, E-mail: ti3@auth.gr [Faculty of Civil Engineering, School of Engineering, Aristotle University of Thessaloniki, 54249, Thessaloniki (Greece); Niemi, Antti J., E-mail: Antti.Niemi@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 803, S-75108, Uppsala (Sweden); Laboratoire de Mathematiques et Physique Theorique CNRS UMR 6083, Fédération Denis Poisson, Université de Tours, Parc de Grandmont, F37200, Tours (France); Department of Physics, Beijing Institute of Technology, Haidian District, Beijing 100081 (China)

    2016-01-28

    The Poisson geometry of a discrete string in three dimensional Euclidean space is investigated. For this the Frenet frames are converted into a spinorial representation, the discrete spinor Frenet equation is interpreted in terms of a transfer matrix formalism, and Poisson brackets are introduced in terms of the spinor components. The construction is then generalised, in a self-similar manner, into an infinite hierarchy of Poisson algebras. As an example, the classical Virasoro (Witt) algebra that determines reparametrisation diffeomorphism along a continuous string, is identified as a particular sub-algebra, in the hierarchy of the discrete string Poisson algebra. - Highlights: • Witt (classical Virasoro) algebra is derived in the case of discrete string. • Infinite dimensional hierarchy of Poisson bracket algebras is constructed for discrete strings. • Spinor representation of discrete Frenet equations is developed.

  12. Advances in discrete differential geometry

    CERN Document Server

    2016-01-01

    This is one of the first books on a newly emerging field of discrete differential geometry and an excellent way to access this exciting area. It surveys the fascinating connections between discrete models in differential geometry and complex analysis, integrable systems and applications in computer graphics. The authors take a closer look at discrete models in differential geometry and dynamical systems. Their curves are polygonal, surfaces are made from triangles and quadrilaterals, and time is discrete. Nevertheless, the difference between the corresponding smooth curves, surfaces and classical dynamical systems with continuous time can hardly be seen. This is the paradigm of structure-preserving discretizations. Current advances in this field are stimulated to a large extent by its relevance for computer graphics and mathematical physics. This book is written by specialists working together on a common research project. It is about differential geometry and dynamical systems, smooth and discrete theories, ...

  13. Fermionic realisations of simple Lie algebras

    CERN Document Server

    de Azcárraga, J A

    2000-01-01

    We study the representation ${\\cal D}$ of a simple compact Lie algebra $\\g$ of rank l constructed with the aid of the hermitian Dirac matrices of a (${\\rm dim} \\g$)-dimensional euclidean space. The irreducible representations of $\\g$ contained in ${\\cal D}$ are found by providing a general construction on suitable fermionic Fock spaces. We give full details not only for the simplest odd and even cases, namely su(2) and su(3), but also for the next (${dim} \\g$)-even case of su(5). Our results are far reaching: they apply to any $\\g$-invariant quantum mechanical system containing ${\\rm dim} \\g$ fermions. Another reason for undertaking this study is to examine the role of the $\\g$-invariant fermionic operators that naturally arise. These are given in terms of products of an odd number of gamma matrices, and include, besides a cubic operator, (l-1) fermionic scalars of higher order. The latter are constructed from the Lie algebra cohomology cocycles, and must be considered to be of theoretical significance simila...

  14. A numerical theory of lattice gas and lattice Boltzmann methods in the computation of solutions to nonlinear advective-diffusive systems

    Energy Technology Data Exchange (ETDEWEB)

    Elton, A.B.H.

    1990-09-24

    A numerical theory for the massively parallel lattice gas and lattice Boltzmann methods for computing solutions to nonlinear advective-diffusive systems is introduced. The convergence theory is based on consistency and stability arguments that are supported by the discrete Chapman-Enskog expansion (for consistency) and conditions of monotonicity (in establishing stability). The theory is applied to four lattice methods: Two of the methods are for some two-dimensional nonlinear diffusion equations. One of the methods is for the one-dimensional lattice method for the one-dimensional viscous Burgers equation. And one of the methods is for a two-dimensional nonlinear advection-diffusion equation. Convergence is formally proven in the L{sub 1}-norm for the first three methods, revealing that they are second-order, conservative, conditionally monotone finite difference methods. Computational results which support the theory for lattice methods are presented. In addition, a domain decomposition strategy using mesh refinement techniques is presented for lattice gas and lattice Boltzmann methods. The strategy allows concentration of computational resources on regions of high activity. Computational evidence is reported for the strategy applied to the lattice gas method for the one-dimensional viscous Burgers equation. 72 refs., 19 figs., 28 tabs.

  15. Weight-lattice discretization of Weyl-orbit functions

    Science.gov (United States)

    Hrivnák, Jiří; Walton, Mark A.

    2016-08-01

    Weyl-orbit functions have been defined for each simple Lie algebra, and permit Fourier-like analysis on the fundamental region of the corresponding affine Weyl group. They have also been discretized, using a refinement of the coweight lattice, so that digitized data on the fundamental region can be Fourier-analyzed. The discretized orbit function has arguments that are redundant if related by the affine Weyl group, while its labels, the Weyl-orbit representatives, invoke the dual affine Weyl group. Here we discretize the orbit functions in a novel way, by using the weight lattice. A cleaner theory results with symmetry between the arguments and labels of the discretized orbit functions. Orthogonality of the new discretized orbit functions is proved, and leads to the construction of unitary, symmetric matrices with Weyl-orbit-valued elements. For one type of orbit function, the matrix coincides with the Kac-Peterson modular S matrix, important for Wess-Zumino-Novikov-Witten conformal field theory.

  16. Discrete R Symmetries and Anomalies

    OpenAIRE

    Michael Dine(Santa Cruz Institute for Particle Physics and Department of Physics, Santa Cruz CA 95064, U.S.A.); Angelo Monteux(Santa Cruz Institute for Particle Physics, University of California Santa Cruz, 1156 High Street, Santa Cruz, U.S.A.)

    2012-01-01

    We comment on aspects of discrete anomaly conditions focussing particularly on $R$ symmetries. We review the Green-Schwarz cancellation of discrete anomalies, providing a heuristic explanation why, in the heterotic string, only the "model-independent dilaton" transforms non-linearly under discrete symmetries; this argument suggests that, in other theories, multiple fields might play a role in anomaly cancellations, further weakening any anomaly constraints at low energies. We provide examples...

  17. Steerable Discrete Cosine Transform

    Science.gov (United States)

    Fracastoro, Giulia; Fosson, Sophie M.; Magli, Enrico

    2017-01-01

    In image compression, classical block-based separable transforms tend to be inefficient when image blocks contain arbitrarily shaped discontinuities. For this reason, transforms incorporating directional information are an appealing alternative. In this paper, we propose a new approach to this problem, namely a discrete cosine transform (DCT) that can be steered in any chosen direction. Such transform, called steerable DCT (SDCT), allows to rotate in a flexible way pairs of basis vectors, and enables precise matching of directionality in each image block, achieving improved coding efficiency. The optimal rotation angles for SDCT can be represented as solution of a suitable rate-distortion (RD) problem. We propose iterative methods to search such solution, and we develop a fully fledged image encoder to practically compare our techniques with other competing transforms. Analytical and numerical results prove that SDCT outperforms both DCT and state-of-the-art directional transforms.

  18. Discrete Thermodynamics of Lasers

    CERN Document Server

    Zilbergleyt, B

    2007-01-01

    The paper offers a discrete thermodynamic model of lasers. Laser is an open system; its equilibrium is based on a balance of two thermodynamic forces, one related to the incoming pumping power and another to the emitted light. The basic expression for such equilibrium is a logistic map, graphical solutions to which are pitchfork bifurcation diagrams. As pumping force increases, the relative populations on the ground and lasing branches tend to zero and unity correspondingly. An interesting feature of this model is the line spectrum of the up and down transitions between the branches beyond bifurcation point. Even in a simple case of 2-level laser with only 2 possible transition types (up and down), the spectra look like sets of the line packets, starting well before the population inversion. This effect is an independent confirmation of the Einstein's prohibition on practical realization of 2-level laser. Multilevel lasers may be approached by employing the idea of thermodynamic activity for the emitting atom...

  19. Discrete anti-gravity

    Science.gov (United States)

    Noyes, H. Pierre; Starson, Scott

    1991-03-01

    Discrete physics, because it replaces time evolution generated by the energy operator with a global bit-string generator (program universe) and replaces fields with the relativistic Wheeler-Feynman action at a distance, allows the consistent formulation of the concept of signed gravitational charge for massive particles. The resulting prediction made by this version of the theory is that free anti-particles near the surface of the earth will fall up with the same acceleration that the corresponding particles fall down. So far as we can see, no current experimental information is in conflict with this prediction of our theory. The experiment crusis will be one of the anti-proton or anti-hydrogen experiments at CERN. Our prediction should be much easier to test than the small effects which those experiments are currently designed to detect or bound.

  20. Discrete anti-gravity

    Energy Technology Data Exchange (ETDEWEB)

    Noyes, H.P. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Starson, S. (STARSON Corp. (USA))

    1991-03-01

    Discrete physics, because it replaces time evolution generated by the energy operator with a global bit-string generator (program universe) and replaces fields'' with the relativistic Wheeler-Feynman action at a distance,'' allows the consistent formulation of the concept of signed gravitational charge for massive particles. The resulting prediction made by this version of the theory is that free anti-particles near the surface of the earth will fall'' up with the same acceleration that the corresponding particles fall down. So far as we can see, no current experimental information is in conflict with this prediction of our theory. The experiment crusis will be one of the anti-proton or anti-hydrogen experiments at CERN. Our prediction should be much easier to test than the small effects which those experiments are currently designed to detect or bound. 23 refs.

  1. Discrete Pearson distributions

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, K.O. [Oak Ridge National Lab., TN (United States); Shenton, L.R. [Georgia Univ., Athens, GA (United States); Kastenbaum, M.A. [Kastenbaum (M.A.), Basye, VA (United States)

    1991-11-01

    These distributions are generated by a first order recursive scheme which equates the ratio of successive probabilities to the ratio of two corresponding quadratics. The use of a linearized form of this model will produce equations in the unknowns matched by an appropriate set of moments (assumed to exist). Given the moments we may find valid solutions. These are two cases; (1) distributions defined on the non-negative integers (finite or infinite) and (2) distributions defined on negative integers as well. For (1), given the first four moments, it is possible to set this up as equations of finite or infinite degree in the probability of a zero occurrence, the sth component being a product of s ratios of linear forms in this probability in general. For (2) the equation for the zero probability is purely linear but may involve slowly converging series; here a particular case is the discrete normal. Regions of validity are being studied. 11 refs.

  2. Immigration and Prosecutorial Discretion.

    Science.gov (United States)

    Apollonio, Dorie; Lochner, Todd; Heddens, Myriah

    Immigration has become an increasingly salient national issue in the US, and the Department of Justice recently increased federal efforts to prosecute immigration offenses. This shift, however, relies on the cooperation of US attorneys and their assistants. Traditionally federal prosecutors have enjoyed enormous discretion and have been responsive to local concerns. To consider how the centralized goal of immigration enforcement may have influenced federal prosecutors in regional offices, we review their prosecution of immigration offenses in California using over a decade's worth of data. Our findings suggest that although centralizing forces influence immigration prosecutions, individual US attorneys' offices retain distinct characteristics. Local factors influence federal prosecutors' behavior in different ways depending on the office. Contrary to expectations, unemployment rates did not affect prosecutors' willingness to pursue immigration offenses, nor did local popular opinion about illegal immigration.

  3. A discrete, finite multiverse

    CERN Document Server

    McKenzie, Alan

    2016-01-01

    The Many Worlds Interpretation (MWI) famously avoids the issue of wave function collapse. Different MWI trees representing the same quantum events can have different topologies, depending upon the observer. However, they are all isomorphic to the group of block universes containing all of the outcomes of all of the events, and so, in that sense, the group of block universes is a more fundamental representation. Different branches of the MWI tree, representing different universes in MWI, ultimately share the same quantum state in a common ancestor branch. This branching topology is incompatible with that of the Minkowski block universe; the resolution is to replace the branches with discrete, parallel block universes, each of which extends from the trunk to the outermost twigs. The number of universes in a branch is proportional to its thickness which, in turn, depends upon the absolute square of the probability amplitude for the state in that branch. Every quantum event may be represented by a kernel of unive...

  4. Thermodynamics of discrete quantum processes

    Science.gov (United States)

    Anders, Janet; Giovannetti, Vittorio

    2013-03-01

    We define thermodynamic configurations and identify two primitives of discrete quantum processes between configurations for which heat and work can be defined in a natural way. This allows us to uncover a general second law for any discrete trajectory that consists of a sequence of these primitives, linking both equilibrium and non-equilibrium configurations. Moreover, in the limit of a discrete trajectory that passes through an infinite number of configurations, i.e. in the reversible limit, we recover the saturation of the second law. Finally, we show that for a discrete Carnot cycle operating between four configurations one recovers Carnot's thermal efficiency.

  5. Principles of discrete time mechanics

    CERN Document Server

    Jaroszkiewicz, George

    2014-01-01

    Could time be discrete on some unimaginably small scale? Exploring the idea in depth, this unique introduction to discrete time mechanics systematically builds the theory up from scratch, beginning with the historical, physical and mathematical background to the chronon hypothesis. Covering classical and quantum discrete time mechanics, this book presents all the tools needed to formulate and develop applications of discrete time mechanics in a number of areas, including spreadsheet mechanics, classical and quantum register mechanics, and classical and quantum mechanics and field theories. A consistent emphasis on contextuality and the observer-system relationship is maintained throughout.

  6. Visualizing Advective and Diffusive Phenomena in Fluid-Rock Interaction using Thermochromic Materials

    Science.gov (United States)

    Heinle, B.; Cardiff, M. A.

    2016-12-01

    The presence of fractures plays an essential role in hydrogeologic transport, as well as geothermal and hydrocarbon industries, as fractures introduce new pathways for flow and transport in host rocks. Transport through these features is often highly non-Fickian, due to the combination of both heterogeneous advection and matrix diffusion. Fracture aperture distributions and contact areas control the ability of fluids to flow through a fracture, and to interact with host rock. The heterogeneous nature of these fracture apertures often lead to preferential fluid pathways that control the prevalence of advective and diffusive processes within the fracture network. To understand how preferential fluid pathways affect these transport processes in detail, an innovative approach is introduced for visualizing advective and diffusive phenomena through the use of thermochromic liquid crystals (TLCs). An artificial fracture with the ability to have its surface roughness altered is constructed and heterogeneous flow and diffusion of heat is observed directly using these TLCs. The surfaces are digitized and simulated in COMSOL Multiphysics where particle tracing is used to determine arrival time curves in the absence of host rock diffusion. The resulting combination of the visual results from lab experiments and particle statistics from the computer model provide a unique method for assessing the impact of both heterogeneous advection and matrix-diffusion on tracer breakthrough in fractures, across a variety of fracture geometries. Figure 1. Image of advective (left) and diffusive (right) phenomena occurring simultaneously as fluid flows through the artificial fracture.

  7. Uncertainty Principles on Two Step Nilpotent Lie Groups

    Indian Academy of Sciences (India)

    S K Ray

    2001-08-01

    We extend an uncertainty principle due to Cowling and Price to two step nilpotent Lie groups, which generalizes a classical theorem of Hardy. We also prove an analogue of Heisenberg inequality on two step nilpotent Lie groups.

  8. Pants on fire: the electrophysiological signature of telling a lie.

    Science.gov (United States)

    Pfister, Roland; Foerster, Anna; Kunde, Wilfried

    2014-01-01

    Even though electroencephalography has played a prominent role for lie detection via personally relevant information, the electrophysiological signature of active lying is still elusive. We addressed this signature with two experiments in which participants helped a virtual police officer to locate a knife. Crucially, before this response, they announced whether they would lie or tell the truth about the knife's location. This design allowed us to study the signature of lie-telling in the absence of rare and personally significant oddball stimuli that are typically used for lie detection via electrophysiological markers, especially the P300 component. Our results indicate that active lying attenuated P300 amplitudes as well as N200 amplitudes for such non-oddball stimuli. These results support accounts that stress the high cognitive demand of lie-telling, including the need to suppress the truthful response and to generate a lie.

  9. Discrete Plane Segmentation and Estimation from a Point Cloud Using Local Geometric Patterns

    Institute of Scientific and Technical Information of China (English)

    Yukiko Kenmochi; Lilian Buzer; Akihiro Sugimoto; Ikuko Shimizu

    2008-01-01

    This paper presents a method for segmenting a 3D point cloud into planar surfaces using recently obtained discrete-geometry results. In discrete geometry, a discrete plane is defined as a set of grid points lying between two parallel planes with a small distance, called thickness. In contrast to the continuous case, there exist a finite number of local geometric patterns (LGPs) appearing on discrete planes. Moreover, such an LGP does not possess the unique normal vector but a set of normal vectors. By using those LGP properties, we first reject non-linear points from a point cloud, and then classify non-rejected points whose LGPs have common normal vectors into a planar-surface-point set. From each segmented point set, we also estimate the values of parameters of a discrete plane by minimizing its thickness.

  10. Twisted Hamiltonian Lie Algebras and Their Multiplicity-Free Representations

    Institute of Scientific and Technical Information of China (English)

    Ling CHEN

    2011-01-01

    We construct a class of new Lie algebras by generalizing the one-variable Lie algebras generated by the quadratic conformal algebras (or corresponding Hamiltonian operators) associated with Poisson algebras and a quasi-derivation found by Xu. These algebras can be viewed as certain twists of Xu's generalized Hamiltonian Lie algebras. The simplicity of these algebras is completely determined. Moreover, we construct a family of multiplicity-free representations of these Lie algebras and prove their irreducibility.

  11. Lie symmetries and differential galois groups of linear equations

    NARCIS (Netherlands)

    Oudshoorn, W.R.; Put, M. van der

    2002-01-01

    For a linear ordinary differential equation the Lie algebra of its infinitesimal Lie symmetries is compared with its differential Galois group. For this purpose an algebraic formulation of Lie symmetries is developed. It turns out that there is no direct relation between the two above objects. In co

  12. 33 CFR 401.92 - Wintering and lying-up.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Wintering and lying-up. 401.92... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations General § 401.92 Wintering and lying-up. No vessel shall winter within the Seaway or lie-up within the Seaway during the navigation...

  13. Lie Pseudogroups à la Cartan from a Modern Perspective

    NARCIS (Netherlands)

    Yudilevich, O.

    2016-01-01

    In 1904-05, the mathematician Élie Cartan published two pioneer papers in which he introduced a structure theory for Lie pseudogroups. Lie pseudogroups are mathematical objects that appear in both differential geometry and in the theory of differential equations as local symmetries of geometric stru

  14. Graded Lie Algebra Generating of Parastatistical Algebraic Relations

    Institute of Scientific and Technical Information of China (English)

    JING Si-Cong; YANG Wei-Min; LI Ping

    2001-01-01

    A new kind of graded Lie algebra (We call it Z2,2 graded Lie algebra) is introduced as a framework for formulating parasupersymmetric theories. By choosing suitable Bose subspace of the Z2,2 graded Lie algebra and using relevant generalized Jacobi identities, we generate the whole algebraic structure of parastatistics.

  15. Extremal projectors for contragredient Lie (super)symmetries (short review)

    CERN Document Server

    Tolstoy, V N

    2010-01-01

    A brief review of the extremal projectors for contragredient Lie (super)symmetries (finite-dimensional simple Lie algebras, basic classical Lie superalgebras, infinite-dimensional affine Kac-Moody algebras and superalgebras, as well as their quantum $q$-analogs) is given. Some bibliographic comments on the applications of extremal projectors are presented.

  16. Focal sampling of cow lying behaviour for automated welfare assessment

    NARCIS (Netherlands)

    Mattachini, G.; Riva, E.; Bisaglia, C.; Pompe, J.C.A.M.; Provolo, G.

    2013-01-01

    the objective of the current study was to determine the number of focal animals required to represent the daily lying behaviour of a herd of lactating dairy cows. the study was carried out at 3 commercial dairy farms. the lying time (h/d) and number of lying bouts (n/d) of 15 ± 3 focal dairy cows,

  17. Universal representations of Lie algebras by coderivations

    OpenAIRE

    Petracci, Emanuela

    2003-01-01

    A class of representations of a Lie superalgebra (over a commutative superring) in its symmetric algebra is studied. As an application we get a direct and natural proof of a strong form of the Poincare'-Birkhoff-Witt theorem, extending this theorem to a class of nilpotent Lie superalgebras. Other applications are presented. Our results are new already for Lie algebras.

  18. Lie symmetry algebra of one-dimensional nonconservative dynamical systems

    Institute of Scientific and Technical Information of China (English)

    Liu Cui-Mei; Wu Run-Heng; Fu Jing-Li

    2007-01-01

    Lie symmetry algebra of linear nonconservative dynamical systems is studied in this paper. By using 1-1 mapping,the Lie point and Lie contact symmetry algebras are obtained from two independent solutions of the one-dimensional linear equations of motion.

  19. Central Extension for the Triangular Derivation Lie Algebra

    Institute of Scientific and Technical Information of China (English)

    Chunming LI; Ping XU

    2012-01-01

    In this paper,we study a class of subalgebras of the Lie algebra of vector fields on n-dimensional torus,which are called the Triangular derivation Lie algebra.We give the structure and the central extension of Triangular derivation Lie algebra.

  20. [Counter-acception or abort and lie].

    Science.gov (United States)

    Maruani, G

    1979-09-01

    In this very short but fiery and violent paper against abortion the author states that most women seeking abortion are actually lying to themselves, pretending they want something which, in reality, they do not want, i.e. an abortion. The laws regulating abortion in most countries are such that a woman is practically forbidden to make an independent decision, despite, or because of the number of counseling sessions and of meetings with doctors that she must go through. Radio, television, newspapers and magazines, friends and relatives, all contribute to make of abortion a run-of-the-mill operation, while it should be seen as scandal, and as the total negation of any maternal instinct.

  1. Lie algebraic noncommuting structures from reparametrisation symmetry

    CERN Document Server

    Gangopadhyay, S

    2007-01-01

    We extend our earlier work of revealing both space-space and space-time noncommuting structures in various models in particle mechanics exhibiting reparametrisation symmetry. We show explicitly (in contrast to the earlier results in our paper \\cite{sg}) that for some special choices of the reparametrisation parameter $\\epsilon$, one can obtain space-space noncommuting structures which are Lie-algebraic in form even in the case of the relativistic free particle. The connection of these structures with the existing models in the literature is also briefly discussed. Further, there exists some values of $\\epsilon$ for which the noncommutativity in the space-space sector can be made to vanish. As a matter of internal consistency of our approach, we also study the angular momentum algebra in details.

  2. On Quantum Lie Nilpotency of Order 2

    Directory of Open Access Journals (Sweden)

    E. A. Kireeva

    2016-01-01

    Full Text Available The paper investigates the free algebras of varieties of associative algebras modulo identities of quantum Lie nilpotency of order 1 and 2. Let q be an invertible element of the ground field K (or of its extension. The element[x,y]q = xy-qyxof the free associative algebra is called a quantum commutator. We consider the algebras modulo identities                                                           [x,y]q = 0                                             (1and                                                      [[x,y]q ,z]q = 0.                                       (2It is natural to consider the aforementioned algebras as the quantum analogs of commutative algebras and algebras of Lie nilpotency of order 2. The free algebras of the varieties of associative algebras modulo the identity of Lie nilpotency of order 2, that is the identity[[x,y] ,z] =0,where [x,y]=xy-yx is a Lie commutator, are of great interest in the theory of algebras with polynomial identities, since it was proved by A.V.Grishin for algebras over fields of characteristic 2, and V.V.Shchigolev for algebras over fields of characteristic p>2, that these algebras contain non-finitely generated T-spaces.We prove in the paper that the algebras modulo identities (1 and (2 are nilpotent in the usual sense and calculate precisely the nilpotency order of these algebras. More precisely, we prove that the free algebra of the variety of associative algebras modulo identity (1 is nilpotent of order 2 if q ≠ ± 1, and nilpotent of order 3 if q = - 1 and the characteristic of K is not equal to 2. It is also proved that the free algebra of the variety of associative algebras modulo identity (2 is nilpotent of order 3 if q3 ≠ 1, q ≠ ± 1, nilpotent of order 4 if q3 = 1, q ≠ 1, and nilpotent of

  3. Detecting Children's Lies: Are Parents Accurate Judges of Their Own Children's Lies?

    Science.gov (United States)

    Talwar, Victoria; Renaud, Sarah-Jane; Conway, Lauryn

    2015-01-01

    The current study investigated whether parents are accurate judges of their own children's lie-telling behavior. Participants included 250 mother-child dyads. Children were between three and 11 years of age. A temptation resistance paradigm was used to elicit a minor transgressive behavior from the children involving peeking at a forbidden toy and…

  4. Detecting Children's Lies: Are Parents Accurate Judges of Their Own Children's Lies?

    Science.gov (United States)

    Talwar, Victoria; Renaud, Sarah-Jane; Conway, Lauryn

    2015-01-01

    The current study investigated whether parents are accurate judges of their own children's lie-telling behavior. Participants included 250 mother-child dyads. Children were between three and 11 years of age. A temptation resistance paradigm was used to elicit a minor transgressive behavior from the children involving peeking at a forbidden toy and…

  5. Metamorphism during temperature gradient with undersaturated advective airflow in a snow sample

    Science.gov (United States)

    Ebner, Pirmin Philipp; Schneebeli, Martin; Steinfeld, Aldo

    2016-04-01

    Snow at or close to the surface commonly undergoes temperature gradient metamorphism under advective flow, which alters its microstructure and physical properties. Time-lapse X-ray microtomography is applied to investigate the structural dynamics of temperature gradient snow metamorphism exposed to an advective airflow in controlled laboratory conditions. Cold saturated air at the inlet was blown into the snow samples and warmed up while flowing across the sample with a temperature gradient of around 50 K m-1. Changes of the porous ice structure were observed at mid-height of the snow sample. Sublimation occurred due to the slight undersaturation of the incoming air into the warmer ice matrix. Diffusion of water vapor opposite to the direction of the temperature gradient counteracted the mass transport of advection. Therefore, the total net ice change was negligible leading to a constant porosity profile. However, the strong recrystallization of water molecules in snow may impact its isotopic or chemical content.

  6. Finite-size particles, advection, and chaos: a collective phenomenon of intermittent bursting.

    Science.gov (United States)

    Medrano-T, Rene O; Moura, Alessandro; Tél, Tamás; Caldas, Iberê L; Grebogi, Celso

    2008-11-01

    We consider finite-size particles colliding elastically, advected by a chaotic flow. The collisionless dynamics has a quasiperiodic attractor and particles are advected towards this attractor. We show in this work that the collisions have dramatic effects in the system's dynamics, giving rise to collective phenomena not found in the one-particle dynamics. In particular, the collisions induce a kind of instability, in which particles abruptly spread out from the vicinity of the attractor, reaching the neighborhood of a coexisting chaotic saddle, in an autoexcitable regime. This saddle, not present in the dynamics of a single particle, emerges due to the collective particle interaction. We argue that this phenomenon is general for advected, interacting particles in chaotic flows.

  7. Discretization error of Stochastic Integrals

    CERN Document Server

    Fukasawa, Masaaki

    2010-01-01

    Asymptotic error distribution for approximation of a stochastic integral with respect to continuous semimartingale by Riemann sum with general stochastic partition is studied. Effective discretization schemes of which asymptotic conditional mean-squared error attains a lower bound are constructed. Two applications are given; efficient delta hedging strategies with transaction costs and effective discretization schemes for the Euler-Maruyama approximation are constructed.

  8. Discrete Mathematics and Its Applications

    Science.gov (United States)

    Oxley, Alan

    2010-01-01

    The article gives ideas that lecturers of undergraduate Discrete Mathematics courses can use in order to make the subject more interesting for students and encourage them to undertake further studies in the subject. It is possible to teach Discrete Mathematics with little or no reference to computing. However, students are more likely to be…

  9. Spurious sea ice formation caused by oscillatory ocean tracer advection schemes

    Science.gov (United States)

    Naughten, Kaitlin A.; Galton-Fenzi, Benjamin K.; Meissner, Katrin J.; England, Matthew H.; Brassington, Gary B.; Colberg, Frank; Hattermann, Tore; Debernard, Jens B.

    2017-08-01

    Tracer advection schemes used by ocean models are susceptible to artificial oscillations: a form of numerical error whereby the advected field alternates between overshooting and undershooting the exact solution, producing false extrema. Here we show that these oscillations have undesirable interactions with a coupled sea ice model. When oscillations cause the near-surface ocean temperature to fall below the freezing point, sea ice forms for no reason other than numerical error. This spurious sea ice formation has significant and wide-ranging impacts on Southern Ocean simulations, including the disappearance of coastal polynyas, stratification of the water column, erosion of Winter Water, and upwelling of warm Circumpolar Deep Water. This significantly limits the model's suitability for coupled ocean-ice and climate studies. Using the terrain-following-coordinate ocean model ROMS (Regional Ocean Modelling System) coupled to the sea ice model CICE (Community Ice CodE) on a circumpolar Antarctic domain, we compare the performance of three different tracer advection schemes, as well as two levels of parameterised diffusion and the addition of flux limiters to prevent numerical oscillations. The upwind third-order advection scheme performs better than the centered fourth-order and Akima fourth-order advection schemes, with far fewer incidents of spurious sea ice formation. The latter two schemes are less problematic with higher parameterised diffusion, although some supercooling artifacts persist. Spurious supercooling was eliminated by adding flux limiters to the upwind third-order scheme. We present this comparison as evidence of the problematic nature of oscillatory advection schemes in sea ice formation regions, and urge other ocean/sea-ice modellers to exercise caution when using such schemes.

  10. Discretization and implicit mapping dynamics

    CERN Document Server

    Luo, Albert C J

    2015-01-01

    This unique book presents the discretization of continuous systems and implicit mapping dynamics of periodic motions to chaos in continuous nonlinear systems. The stability and bifurcation theory of fixed points in discrete nonlinear dynamical systems is reviewed, and the explicit and implicit maps of continuous dynamical systems are developed through the single-step and multi-step discretizations. The implicit dynamics of period-m solutions in discrete nonlinear systems are discussed. The book also offers a generalized approach to finding analytical and numerical solutions of stable and unstable periodic flows to chaos in nonlinear systems with/without time-delay. The bifurcation trees of periodic motions to chaos in the Duffing oscillator are shown as a sample problem, while the discrete Fourier series of periodic motions and chaos are also presented. The book offers a valuable resource for university students, professors, researchers and engineers in the fields of applied mathematics, physics, mechanics,...

  11. Solving Time-Fractional Advection-Dispersion Equation by Variable Weights Particle Tracking Method

    Science.gov (United States)

    Cao, Shaohua; Jiang, Jianguo; Wu, Jichun

    2017-09-01

    Particle tracking method is an efficient and reliable method to solve time-fractional advection-dispersion equation, which can describe anomalous transport in heterogeneous porous media. However, this method will lead to severe fluctuation or disappearance of solutions if the concentration value is small. A variable weights method is developed to conquer the shortcoming of particle tracking method. Then, one-dimensional and two-dimensional time-fractional advection-dispersion equations are solved by the variable weights particle tracking method. Compared to traditional particle tracking method, the variable weights version may eliminate the fluctuation and improve the accuracy by orders of magnitude without more computational cost.

  12. Advection of NH3 over a pasture field and its effect on gradient flux measurements

    Directory of Open Access Journals (Sweden)

    M. A. Sutton

    2009-07-01

    Full Text Available Deposition of atmospheric ammonia (NH3 to semi-natural ecosystems leads to serious adverse effects, such as acidification and eutrophication. A step in quantifying such effects is the measurement of NH3 fluxes over semi-natural and agricultural land. However, measurement of NH3 fluxes over vegetation in the vicinity of strong NH3 sources is challenging, since NH3 emissions are highly heterogeneous. Indeed, under such conditions, local advection errors may alter the measured fluxes. In this study, local advection errors (ΔFz,adv were estimated over a 14 ha grassland field, which was successively cut and fertilised, as part of the GRAMINAE integrated Braunschweig experiment. The magnitude of ΔFz,adv was determined up to 810 m downwind from farm buildings emitting between 6.2 and 9.9 kg NH3 day−1. The GRAMINAE experiment provided a unique opportunity to compare two methods of estimating ΔFz,adv: one inference method based on measurements of horizontal concentration gradients, and one based on inverse dispersion modelling with a two-dimensional model. Two sources of local advection were clearly identified: the farm NH3 emissions leading to positive ΔFz,adv ("bias towards emissions" and field NH3 emissions, which led to a negative ΔFz,adv ("bias towards deposition". The local advection flux from the farm was in the range 0 to 27 ng NH3 m−2 s−1 at 610 m from the farm, whereas ΔFz,adv due to field emission was proportional to the local flux, and ranged between −209 and 13 ng NH3 m−2 s−1. The local advection flux ΔFz,adv was either positive or negative depending on the magnitude of these two contributions. The modelled and inferred advection errors agreed well. The inferred advection errors, relative to the vertical flux at 1 m height, were 52% on average, before the field was cut, and less than 2.1% when the field was fertilised. The variability of the advection errors in response to changes in micrometeorological conditions is also

  13. Semi-Lagrangian advection-propagation (SLAP) scheme for three-dimensional interface tracking

    Science.gov (United States)

    Aldredge, R. C.

    2010-06-01

    A fully three-dimensional semi-Lagrangian scheme is developed for computing the evolution of advected self-propagating surfaces (e.g., premixed flames) governed by a level-set advection-propagation equation. The scheme provides third-order spatial accuracy and shape preservation. Example numerical simulations of three-dimensional front propagation are presented to illustrate the capability of the scheme of capturing cusp formation and associated surface-area annihilation as well as the formation and consumption of detached closed-surface pockets behind fronts propagating in highly vortical flow.

  14. Automorphisms of Strong Homotopy Lie Algebras of Local Observables

    CERN Document Server

    Ritter, Patricia

    2015-01-01

    There is a well-established procedure of assigning a strong homotopy Lie algebra of local observables to a multisymplectic manifold which can be regarded as part of a categorified Poisson structure. For a 2-plectic manifold, the resulting Lie 2-algebra is isomorphic to a sub Lie 2-algebra of a natural Lie 2-algebra structure on an exact Courant algebroid. We generalize this statement to arbitrary n-plectic manifolds and study automorphisms on the arising Lie n-algebras. Our observations may be useful in studying the quantization problem on multisymplectic manifolds.

  15. Determinantal formulae for the Casimir operators of inhomogeneous Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Campoamor-Stursberg, Rutwig [Dpto. Geometria y Topologia, Fac CC Matematicas, Universidad Complutense de Madrid, Plaza de Ciencias, 3, E-28040 Madrid (Spain)

    2006-03-10

    Contractions of Lie algebras are combined with the classical matrix method of Gel'fand to obtain matrix formulae for the Casimir operators of inhomogeneous Lie algebras. The method is presented for the inhomogeneous pseudo-unitary Lie algebras Iu(p,q). This procedure is extended to contractions of Iu(p,q) isomorphic to an extension by a derivation of the inhomogeneous special pseudo-unitary Lie algebras Isu(p-1,q), providing an additional analytical method to obtain their invariants. Further, matrix formulae for the invariants of other inhomogeneous Lie algebras are presented.

  16. Restricted and quasi-toral restricted Lie-Rinehart algebras

    Directory of Open Access Journals (Sweden)

    Sun Bing

    2015-09-01

    Full Text Available In this paper, we introduce the definition of restrictable Lie-Rinehart algebras, the concept of restrictability is by far more tractable than that of a restricted Lie-Rinehart algebra. Moreover, we obtain some properties of p-mappings and restrictable Lie-Rinehart algebras. Finally, we give some sufficient conditions for the commutativity of quasi-toral restricted Lie-Rinehart algebras and study how a quasi-toral restricted Lie-Rinehart algebra with zero center and of minimal dimension should be.

  17. Pro-Lie Groups: A Survey with Open Problems

    Directory of Open Access Journals (Sweden)

    Karl H. Hofmann

    2015-07-01

    Full Text Available A topological group is called a pro-Lie group if it is isomorphic to a closed subgroup of a product of finite-dimensional real Lie groups. This class of groups is closed under the formation of arbitrary products and closed subgroups and forms a complete category. It includes each finite-dimensional Lie group, each locally-compact group that has a compact quotient group modulo its identity component and, thus, in particular, each compact and each connected locally-compact group; it also includes all locally-compact Abelian groups. This paper provides an overview of the structure theory and the Lie theory of pro-Lie groups, including results more recent than those in the authors’ reference book on pro-Lie groups. Significantly, it also includes a review of the recent insight that weakly-complete unital algebras provide a natural habitat for both pro-Lie algebras and pro-Lie groups, indeed for the exponential function that links the two. (A topological vector space is weakly complete if it is isomorphic to a power RX of an arbitrary set of copies of R. This class of real vector spaces is at the basis of the Lie theory of pro-Lie groups. The article also lists 12 open questions connected to pro-Lie groups.

  18. Operadic quantization as a tool for discrete geometry

    Science.gov (United States)

    Paal, E.; Virkepu, J.

    2014-09-01

    The operadic Lax representations of the harmonic oscillator are used to construct the quantum counterparts of 3d real Lie algebras in the Bianchi classification. The Jacobi operators of these quantum algebras are studied. It is shown how the energy conservation is related to the Jacobi identity and how the quantization leads to an anomaly - the quantum violation of the Jacobi relations. By using the nonvanishing quantum Jacobi operators, the derivative quantum algebra for a triple of 3d real Lie algebras is defined. It is proposed that the derivative algebra is the 3d real Heisenberg algebra. From this it follows that in this model only the discrete values of the spatial coordinates are physically allowed.

  19. Discrete Darboux transformation for discrete polynomials of hypergeometric type

    Science.gov (United States)

    Bangerezako, Gaspard

    1998-03-01

    The Darboux transformation, well known in second-order differential operator theory, is applied to the difference equations satisfied by the discrete hypergeometric polynomials (Charlier, Meixner-Kravchuk, Hahn).

  20. Moving Picture, Lying Image: Unreliable Cinematic Narratives

    Directory of Open Access Journals (Sweden)

    Csönge Tamás

    2015-08-01

    Full Text Available By coining the term “unreliable narrator” Wayne Booth hypothesized another agent in his model besides the author, the implicit author, to explain the double coding of narratives where a distorted view of reality and the exposure of this distortion are presented simultaneously. The article deals with the applicability of the concept in visual narratives. Since unreliability is traditionally considered to be intertwined with first person narratives, it works through subjective mediators. According to scholarly literature on the subject, the narrator has to be strongly characterized, or in other words, anthropomorphized. In the case of film, the main problem is that the narrator is either missing or the narration cannot be attributed entirely to them. There is a medial rupture where the apparatus mediates the story instead of a character’s oral or written discourse. The present paper focuses on some important but overlooked questions about the nature of cinematic storytelling through a re-examination of |the lying flashback in Alfred Hitchcock's Stage Fright. Can a character-narrator control the images the viewer sees? How can the filmic image still be unreliable without having an anthropomorphic narrator? How useful is the term focalization when we are dealing with embedded character-narratives in film?

  1. Polytope expansion of Lie characters and applications

    Energy Technology Data Exchange (ETDEWEB)

    Walton, Mark A., E-mail: walton@uleth.ca [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta T1K 3M4 (Canada)

    2013-12-15

    The weight systems of finite-dimensional representations of complex, simple Lie algebras exhibit patterns beyond Weyl-group symmetry. These patterns occur because weight systems can be decomposed into lattice polytopes in a natural way. Since lattice polytopes are relatively simple, this decomposition is useful, in addition to being more economical than the decomposition into single weights. An expansion of characters into polytope sums follows from the polytope decomposition of weight systems. We study this polytope expansion here. A new, general formula is given for the polytope sums involved. The combinatorics of the polytope expansion are analyzed; we point out that they are reduced from those of the Weyl character formula (described by the Kostant partition function) in an optimal way. We also show that the weight multiplicities can be found easily from the polytope multiplicities, indicating explicitly the equivalence of the two descriptions. Finally, we demonstrate the utility of the polytope expansion by showing how polytope multiplicities can be used in the calculation of tensor product decompositions, and subalgebra branching rules.

  2. Devious Lies: Adventures in Freelance Science Outreach

    Science.gov (United States)

    Fatland, D. R.

    2003-12-01

    Observations are given from two freelance science outreach projects undertaken by the author: Tutoring at-risk secondary students and teaching astronomy to 5th-7th graders in a camp retreat environment. Two recurring thematic challenges in these experiences are considered: First the 'Misperception Problem', the institutionalized chasm between the process of doing science and K-12 science education (wherein science is often portrayed as something distant and inaccessible, while ironically children are necessarily excellent scientists). And second the 'Engagement Problem', engaging a student's attention and energy by matching teaching material and--more importantly--teaching techniques to the student's state of development. The objective of this work is twofold: To learn how to address these two challenges and to empower the students in a manner independent of the scientific content of any particular subject. An underlying hypothesis is that confidence to problem solve (a desirable life-skill) can be made more accessible through a combination of problem solving by the student and seeing how others have solved seemingly impossible problems. This hypothesis (or agenda) compels an emphasis on critical thinking and raises the dilemma of reconciling non-directed teaching with very pointed conclusions about the verity of pseudo-science and ideas prevalent about science in popular culture. An interesting pedagogical found-object in this regard is the useful 'devious lie' which can encourage a student to question the assumption that the teacher (and by extension any professed expert) has the right answers.

  3. Relativity symmetries and Lie algebra contractions

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Dai-Ning; Kong, Otto C.W., E-mail: otto@phy.ncu.edu.tw

    2014-12-15

    We revisit the notion of possible relativity or kinematic symmetries mutually connected through Lie algebra contractions under a new perspective on what constitutes a relativity symmetry. Contractions of an SO(m,n) symmetry as an isometry on an m+n dimensional geometric arena which generalizes the notion of spacetime are discussed systematically. One of the key results is five different contractions of a Galilean-type symmetry G(m,n) preserving a symmetry of the same type at dimension m+n−1, e.g. a G(m,n−1), together with the coset space representations that correspond to the usual physical picture. Most of the results are explicitly illustrated through the example of symmetries obtained from the contraction of SO(2,4), which is the particular case for our interest on the physics side as the proposed relativity symmetry for “quantum spacetime”. The contractions from G(1,3) may be relevant to real physics.

  4. Low-lying excitations in 72Ni

    Science.gov (United States)

    Morales, A. I.; Benzoni, G.; Watanabe, H.; Nishimura, S.; Browne, F.; Daido, R.; Doornenbal, P.; Fang, Y.; Lorusso, G.; Patel, Z.; Rice, S.; Sinclair, L.; Söderström, P.-A.; Sumikama, T.; Wu, J.; Xu, Z. Y.; Yagi, A.; Yokoyama, R.; Baba, H.; Avigo, R.; Bello Garrote, F. L.; Blasi, N.; Bracco, A.; Camera, F.; Ceruti, S.; Crespi, F. C. L.; de Angelis, G.; Delattre, M.-C.; Dombradi, Zs.; Gottardo, A.; Isobe, T.; Kojouharov, I.; Kurz, N.; Kuti, I.; Matsui, K.; Melon, B.; Mengoni, D.; Miyazaki, T.; Modamio-Hoyborg, V.; Momiyama, S.; Napoli, D. R.; Niikura, M.; Orlandi, R.; Sakurai, H.; Sahin, E.; Sohler, D.; Shaffner, H.; Taniuchi, R.; Taprogge, J.; Vajta, Zs.; Valiente-Dobón, J. J.; Wieland, O.; Yalcinkaya, M.

    2016-03-01

    Low-lying excited states in 72Ni have been investigated in an in-flight fission experiment at the RIBF facility of the RIKEN Nishina Center. The combination of the state-of-the-art BigRIPS and EURICA setups has allowed for a very accurate study of the β decay from 72Co to 72Ni, and has provided first experimental information on the decay sequence 72Fe→72Co→72Ni and on the delayed neutron-emission branch 73Co→72Ni . Accordingly, we report nearly 60 previously unobserved γ transitions which deexcite 21 new levels in 72Ni. Evidence for the location of the so-sought-after (42+) ,(62+) , and (81+) seniority states is provided. As well, the existence of a low-spin β -decaying isomer in odd-odd neutron-rich Co isotopes is confirmed for mass A =72 . The new experimental information is compared to simple shell-model calculations including only neutron excitations across the f p g shells. It is shown that, in general, the calculations reproduce well the observed states.

  5. The origin of discrete particles

    CERN Document Server

    Bastin, T

    2009-01-01

    This book is a unique summary of the results of a long research project undertaken by the authors on discreteness in modern physics. In contrast with the usual expectation that discreteness is the result of mathematical tools for insertion into a continuous theory, this more basic treatment builds up the world from the discrimination of discrete entities. This gives an algebraic structure in which certain fixed numbers arise. As such, one agrees with the measured value of the fine-structure constant to one part in 10,000,000 (10 7 ). Sample Chapter(s). Foreword (56 KB). Chapter 1: Introduction

  6. Invariant Differential Operators for Non-Compact Lie Algebras Parabolically Related to Conformal Lie Algebras

    CERN Document Server

    Dobrev, V K

    2013-01-01

    In the present paper we continue the project of systematic construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we call 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduce the new notion of {\\it parabolic relation} between two non-compact semisimple Lie algebras g and g' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. Thus, we consider the exceptional algebra E_{7(7)} which is parabolically related to the CLA E_{7(-25)}, the parabolic subalgebras including E_{6(6)} and E_{6(-6)} . Other interesting examples are the orthogonal algebras so(p,q) all of which are parabolically related to the conformal algebra so(n,2) with p+q=n+2, the parabolic subalgebras including the Lorentz subalgebra so(n-1,1) and its analogs so(p-1,...

  7. Shell model for time-correlated random advection of passive scalars

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Muratore-Ginanneschi, P.

    1999-01-01

    We study a minimal shell model for the advection of a passive scalar by a Gaussian time-correlated velocity field. The anomalous scaling properties of the white noise limit are studied analytically. The effect of the time correlations are investigated using perturbation theory around the white...

  8. Spectrum of Optically Thin Advection Dominated Accretion Flow around a Black Hole Application to Sgr A*

    CERN Document Server

    Manmoto, T; Kusunose, M

    1997-01-01

    The global structure of optically thin advection dominated accretion flows which are composed of two-temperature plasma around black holes is calculated. We adopt the full set of basic equations including the advective energy transport in the energy equation for the electrons. The spectra emitted by the optically thin accretion flows are also investigated. The radiation mechanisms which are taken into accout are bremsstrahlung, synchrotron emission, and Comptonization. The calculation of the spectra and that of the structure of the accretion flows are made to be completely consistent by calculating the radiative cooling rate at each radius. As a result of the advection domination for the ions, the heat transport from the ions to the electrons becomes practically zero and the radiative cooling balances with the advective heating in the energy equation of the electrons. Following up on the successful work of Narayan et al. (1995), we applied our model to the spectrum of Sgr A*. We find that the spectrum of Sgr ...

  9. Advective Accretion Disks around Black Holes with Account of Magnetic Fields

    Science.gov (United States)

    Bisnovatyi-Kogan, G. S.

    2002-09-01

    Accretion disc theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disc. One of the most important new invention of this theory was a phenomenological treatment of the turbulent viscosity, known as "alpha" prescription, when the (rφ) component of the stress tensor was approximated by (αP) with a unknown constant α. This prescription played the role in the accretion disc theory as well important as the mixing-length theory of convection for stellar evolution. Sources of turbulence in the accretion disc are discussed, including nonlinear hydrodynamic turbulence, convection and magnetic field role. In parallel to the optically thick geometrically thin accretion disc models, a new branch of the optically thin accretion disc models was discovered, with a larger thickness for the same total luminosity. The choice between these solutions should be done of the base of a stability analysis. The ideas underlying the necessity to include advec-tion into the accretion disc theory are presented and first models with advection are reviewed. The present status of the solution for a low-luminous optically thin accretion disc model with advection is discussed and the limits for an advection dominated accretion flows (ADAF) imposed by the presence of magnetic field are analyzed.

  10. Effects of upwinding on the solution of a 1-D advection-diffusion problem

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, V.

    1991-12-01

    A one-dimensional advection-diffusion problem whose solution is known was solved using TOPAZ2D. Two numerical upwinding techniques were used to damp out the numerical oscillations that occur. Comparisons between the exact and numerical solution were made.

  11. Satellite-advection based solar forecasting: lessons learned and progress towards probabalistic solar forecasting

    Science.gov (United States)

    Rogers, M. A.

    2015-12-01

    Using satellite observations from GOES-E and GOES-W platforms in concert with GFS-derived cloud-level winds and a standalone radiative transfer model, an advection-derived forecast for surface GHI over the continental United States, with intercomparison between forecasts for four zones over the CONUS and Central Pacific with SURFRAD results. Primary sources for error in advection-based forecasts, primarily driven by false- or mistimed ramp events are discussed, with identification of error sources quantified along with techniques used to improve advection-based forecasts to approximately 10% MAE for designated surface locations. Development of a blended steering wind product utilizing NWP output combined with satellite-derived winds from AMV techniques to improve 0-1 hour advection forecasts will be discussed. Additionally, the use of two years' of solar forecast observations in the development of a prototype probablistic forecast for ramp events will be shown, with the intent of increasing the use of satellite-derived forecasts for grid operators and optimizing integration of renewable resources into the power grid. Elements of the work were developed under the 'Public-Private-Academic Partnership to Advance Solar Power Forecasting' project spearheaded by the National Center for Atmospheric Research.

  12. Impacts of photon bending on observational aspects of Two Component Advective Flow

    CERN Document Server

    Chatterjee, Arka

    2016-01-01

    Nature of photon trajectories in a curved spacetime around black holes are studied without constraining their motion to any plane. Impacts of photon bending are separately scrutinized for Keplerian and CENBOL components of Two Component Advective Flow (TCAF) model. Parameters like Red shift, Bolometric Flux, temperature profile and time of arrival of photons are also computed.

  13. Comparison of different computer platforms for running the Versatile Advection Code

    NARCIS (Netherlands)

    Toth, G.; Keppens, R.; Sloot, P.; Bubak, M.; Hertzberger, B.

    1998-01-01

    The Versatile Advection Code is a general tool for solving hydrodynamical and magnetohydrodynamical problems arising in astrophysics. We compare the performance of the code on different computer platforms, including work stations and vector and parallel supercomputers. Good parallel scaling can be a

  14. Quantum Trilogy: Discrete Toda, Y-System and Chaos

    CERN Document Server

    Yamazaki, Masahito

    2016-01-01

    We discuss a discretization of the quantum Toda field theory associated with a semisimple finite-dimensional Lie algebra or a tamely-laced infinite-dimensional Kac-Moody algebra $G$, generalizing the previous construction of discrete quantum Liouville theory for the case $G=A_1$. The model is defined on a discrete two-dimensional lattice, whose spatial direction is of length $L$. In addition we also find a "discretized extra dimension" whose width is given by the rank $r$ of $G$, which decompactifies in the large $r$ limit. For the case of $G=A_N$ or $A_{N-1}^{(1)}$, we find a symmetry exchanging $L$ and $N$ under appropriate spatial boundary conditions. The dynamical time evolution rule of the model is a quantizations of the so-called Y-system, and the theory can be well-described by the quantum cluster algebra. We discuss possible implications for recent discussions of quantum chaos, and comment on the relation with the quantum higher Teichmuller theory of type $A_N$.

  15. Prediction of the moments in advection-diffusion lattice Boltzmann method. I. Truncation dispersion, skewness, and kurtosis

    Science.gov (United States)

    Ginzburg, Irina

    2017-01-01

    The effect of the heterogeneity in the soil structure or the nonuniformity of the velocity field on the modeled resident time distribution (RTD) and breakthrough curves is quantified by their moments. While the first moment provides the effective velocity, the second moment is related to the longitudinal dispersion coefficient (kT) in the developed Taylor regime; the third and fourth moments are characterized by their normalized values skewness (Sk) and kurtosis (Ku), respectively. The purpose of this investigation is to examine the role of the truncation corrections of the numerical scheme in kT, Sk, and Ku because of their interference with the second moment, in the form of the numerical dispersion, and in the higher-order moments, by their definition. Our symbolic procedure is based on the recently proposed extended method of moments (EMM). Originally, the EMM restores any-order physical moments of the RTD or averaged distributions assuming that the solute concentration obeys the advection-diffusion equation in multidimensional steady-state velocity field, in streamwise-periodic heterogeneous structure. In our work, the EMM is generalized to the fourth-order-accurate apparent mass-conservation equation in two- and three-dimensional duct flows. The method looks for the solution of the transport equation as the product of a long harmonic wave and a spatially periodic oscillating component; the moments of the given numerical scheme are derived from a chain of the steady-state fourth-order equations at a single cell. This mathematical technique is exemplified for the truncation terms of the two-relaxation-time lattice Boltzmann scheme, using plug and parabolic flow in straight channel and cylindrical capillary with the d2Q9 and d3Q15 discrete velocity sets as simple but illustrative examples. The derived symbolic dependencies can be readily extended for advection by another, Newtonian or non-Newtonian, flow profile in any-shape open-tabular conduits. It is

  16. A novel method for analytically solving a radial advection-dispersion equation

    Science.gov (United States)

    Lai, Keng-Hsin; Liu, Chen-Wuing; Liang, Ching-Ping; Chen, Jui-Sheng; Sie, Bing-Ruei

    2016-11-01

    An analytical solution for solute transport in a radial flow field has a variety of practical applications in the study of the transport in push-pull/divergent/convergent flow tracer tests, aquifer remediation by pumping and aquifer storage and recovery. However, an analytical solution for radial advective-dispersive transport has been proven very difficult to develop and relatively few in subsurface hydrology have made efforts to do so, because variable coefficients in the governing partial differential equations. Most of the solutions for radial advective-dispersive transport presented in the literature have generally been solved semi-analytically with the final concentration values being obtained with the help of a numerical Laplace inversion. This study presents a novel solution strategy for analytically solving the radial advective-dispersive transport problem. A Laplace transform with respect to the time variable and a generalized integral transform technique with respect to the spatial variable are first performed to convert the transient governing partial differential equations into an algebraic equation. Subsequently, the algebraic equation is solved using simple algebraic manipulations, easily yielding the solution in the transformed domain. The solution in the original domain is ultimately obtained by successive applications of the Laplace and corresponding generalized integral transform inversions. A convergent flow tracer test is used to demonstrate the robustness of the proposed method for deriving an exact analytical solution to the radial advective-dispersive transport problem. The developed analytical solution is verified against a semi-analytical solution taken from the literature. The results show perfect agreement between our exact analytical solution and the semi-analytical solution. The solution method presented in this study can be applied to create more comprehensive analytical models for a great variety of radial advective

  17. Boundary value problem for one-dimensional fractional differential advection-dispersion equation

    Directory of Open Access Journals (Sweden)

    Khasambiev Mokhammad Vakhaevich

    2014-07-01

    Full Text Available An equation commonly used to describe solute transport in aquifers has attracted more attention in recent years. After a formal study of some aspects of the advection-diffusion equation, basically from the mathematical point of view with the solution of a differential equation with fractional derivative, the main interest to this problem shifted onto physical aspects of the dynamical system, such as the total energy and the dynamical response. In this regard it should be pointed out that the interaction with environment is expressed in terms of stochastic arrow of time. This allows one also to reach a progress in one more issue. Formerly the equation of advection-diffusion was not obtained from any physical principles. However, mainly the success concerns linear fractional systems. In fact, there are many cases in which linear treatments are not sufficient. The more general systems described by nonlinear fractional differential equations have not been studied enough. The ordinary calculus brings out clearly that essentially new phenomena occur in nonlinear systems, which generally cannot occur in linear systems. Due to vast range of application of the fractional advection-dispersion equation, a lot of work has been done to find numerical solution and fundamental solution of this equation. The research on the analytical solution of initial-boundary problem for space-fractional advection-dispersion equation is relatively new and is still at an early stage of development. In this paper, we will take use of the method of variable separation to solve space-fractional advection-dispersion equation with initial boundary data.

  18. Fast and accurate advection of sharp discontinuities in Geophysical flows using hybrid implicit surfaces

    Science.gov (United States)

    Samuel, Henri

    2010-05-01

    Advection is one of the major processes that commonly acts on various scales in nature (core formation, mantle convective stirring, multi-phase flows in magma chambers, salt diapirism ...). While this process can be modeled numerically by solving conservation equations, various geodynamic scenarios involve advection of quantities with sharp discontinuities. Unfortunately, in these cases modeling numerically pure advection becomes very challenging, in particular because sharp discontinuities lead to numerical instabilities, which prevent the local use of high order numerical schemes. Several approaches have been used in computational geodynamics in order to overcome this difficulty, with variable amounts of success. Despite the use of correcting filters or non-oscillatory, shock-preserving schemes, Eulerian (fixed grid) techniques generally suffer from artificial numerical diffusion. Lagrangian approaches (dynamic grids or particles) tend to be more popular in computational geodynamics because they are not prone to excessive numerical diffusion. However, these approaches are generally computationally expensive, especially in 3D, and can suffer from spurious statistical noise. As an alternative to these aforementioned approaches, I have applied a relatively recent Particle Level set method [Enright et al., 2002] for modeling advection of quantities with the presence of sharp discontinuities. I have adapted this improved method, which combines the best of Eulerian and Lagrangian approaches, and I have tested it against well known benchmarks and classical Geodynamic flows. In each case the Particle Level Set method accuracy equals or is better than other Eulerian and Lagrangian methods, and leads to significantly smaller computational cost, in particular in three-dimensional flows, where the reduction of computational time for modeling advection processes is most needed.

  19. Modeling the advection of discontinuous quantities in Geophysical flows using Particle Level Sets

    Science.gov (United States)

    Aleksandrov, V.; Samuel, H.; Evonuk, M.

    2010-12-01

    Advection is one of the major processes that commonly acts on various scales in nature (core formation, mantle convective stirring, multi-phase flows in magma chambers, salt diapirism ...). While this process can be modeled numerically by solving conservation equations, various geodynamic scenarios involve advection of quantities with sharp discontinuities. Unfortunately, in these cases modeling numerically pure advection becomes very challenging, in particular because sharp discontinuities lead to numerical instabilities, which prevent the local use of high order numerical schemes. Several approaches have been used in computational geodynamics in order to overcome this difficulty, with variable amounts of success. Despite the use of correcting filters or non-oscillatory, shock-preserving schemes, Eulerian (fixed grid) techniques generally suffer from artificial numerical diffusion. Lagrangian approaches (dynamic grids or particles) tend to be more popular in computational geodynamics because they are not prone to excessive numerical diffusion. However, these approaches are generally computationally expensive, especially in 3D, and can suffer from spurious statistical noise. As an alternative to these aforementioned approaches, we have applied a relatively recent Particle Level set method [Enright et al., 2002] for modeling advection of quantities with the presence of sharp discontinuities. We have tested this improved method, which combines the best of Eulerian and Lagrangian approaches, against well known benchmarks and classical Geodynamic flows. In each case the Particle Level Set method accuracy equals or is better than other Eulerian and Lagrangian methods, and leads to significantly smaller computational cost, in particular in three-dimensional flows, where the reduction of computational time for modeling advection processes is most needed.

  20. Discrete geodesics and cellular automata

    CERN Document Server

    Arrighi, Pablo

    2015-01-01

    This paper proposes a dynamical notion of discrete geodesics, understood as straightest trajectories in discretized curved spacetime. The notion is generic, as it is formulated in terms of a general deviation function, but readily specializes to metric spaces such as discretized pseudo-riemannian manifolds. It is effective: an algorithm for computing these geodesics naturally follows, which allows numerical validation---as shown by computing the perihelion shift of a Mercury-like planet. It is consistent, in the continuum limit, with the standard notion of timelike geodesics in a pseudo-riemannian manifold. Whether the algorithm fits within the framework of cellular automata is discussed at length. KEYWORDS: Discrete connection, parallel transport, general relativity, Regge calculus.

  1. Exact analysis of discrete data

    CERN Document Server

    Hirji, Karim F

    2005-01-01

    Researchers in fields ranging from biology and medicine to the social sciences, law, and economics regularly encounter variables that are discrete or categorical in nature. While there is no dearth of books on the analysis and interpretation of such data, these generally focus on large sample methods. When sample sizes are not large or the data are otherwise sparse, exact methods--methods not based on asymptotic theory--are more accurate and therefore preferable.This book introduces the statistical theory, analysis methods, and computation techniques for exact analysis of discrete data. After reviewing the relevant discrete distributions, the author develops the exact methods from the ground up in a conceptually integrated manner. The topics covered range from univariate discrete data analysis, a single and several 2 x 2 tables, a single and several 2 x K tables, incidence density and inverse sampling designs, unmatched and matched case -control studies, paired binary and trinomial response models, and Markov...

  2. Causal Dynamics of Discrete Surfaces

    Directory of Open Access Journals (Sweden)

    Pablo Arrighi

    2014-03-01

    Full Text Available We formalize the intuitive idea of a labelled discrete surface which evolves in time, subject to two natural constraints: the evolution does not propagate information too fast; and it acts everywhere the same.

  3. Discrete Event Programming with Simkit

    OpenAIRE

    Buss, Arnold

    2001-01-01

    This paper is a brief introduction to the use of Simkit, a software package for implementing Discrete Event Simulation (DES) models. Simkit is written in Java (for any operating system with Java 2TM ).

  4. Multiscale expansions in discrete world

    Indian Academy of Sciences (India)

    Ömer Ünsal; Filiz Taşcan; Mehmet Naci Özer

    2014-07-01

    In this paper, we show the attainability of KdV equation from some types of nonlinear Schrödinger equation by using multiscale expansions discretely. The power of this manageable method is confirmed by applying it to two selected nonlinear Schrödinger evolution equations. This approach can also be applied to other nonlinear discrete evolution equations. All the computations have been made with Maple computer packet program.

  5. Discrete solitons in graphene metamaterials

    OpenAIRE

    Bludov, Yuliy V.; Smirnova, Daria A.; Kivshar, Yuri S.; Peres, N. M. R.; Vasilevskiy, Mikhail

    2014-01-01

    We study nonlinear properties of multilayer metamaterials created by graphene sheets separated by dielectric layers. We demonstrate that such structures can support localized nonlinear modes described by the discrete nonlinear Schr\\"{o}dinger equation and that its solutions are associated with stable discrete plasmon solitons. We also analyze the nonlinear surface modes in truncated graphene metamaterials being a nonlinear analog of surface Tamm states. Fundação para a Ciência e a Tecnolog...

  6. Discrete solitons in graphene metamaterials

    Science.gov (United States)

    Bludov, Yu. V.; Smirnova, D. A.; Kivshar, Yu. S.; Peres, N. M. R.; Vasilevskiy, M. I.

    2015-01-01

    We study nonlinear properties of multilayer metamaterials created by graphene sheets separated by dielectric layers. We demonstrate that such structures can support localized nonlinear modes described by the discrete nonlinear Schrödinger equation and that its solutions are associated with stable discrete plasmon solitons. We also analyze the nonlinear surface modes in truncated graphene metamaterials being a nonlinear analog of surface Tamm states.

  7. Cartan geometries and their symmetries a Lie algebroid approach

    CERN Document Server

    Crampin, Mike

    2016-01-01

    In this book we first review the ideas of Lie groupoid and Lie algebroid, and the associated concepts of connection. We next consider Lie groupoids of fibre morphisms of a fibre bundle, and the connections on such groupoids together with their symmetries. We also see how the infinitesimal approach, using Lie algebroids rather than Lie groupoids, and in particular using Lie algebroids of vector fields along the projection of the fibre bundle, may be of benefit. We then introduce Cartan geometries, together with a number of tools we shall use to study them. We take, as particular examples, the four classical types of geometry: affine, projective, Riemannian and conformal geometry. We also see how our approach can start to fit into a more general theory. Finally, we specialize to the geometries (affine and projective) associated with path spaces and geodesics, and consider their symmetries and other properties.

  8. Lie transforms and their use in Hamiltonian perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Cary, J.R.

    1978-06-01

    A review is presented of the theory of Lie transforms as applied to Hamiltonian systems. We begin by presenting some general background on the Hamiltonian formalism and by introducing the operator notation for canonical transformations. We then derive the general theory of Lie transforms. We derive the formula for the new Hamiltonian when one uses a Lie transform to effect a canonical transformation, and we use Lie transforms to prove a very general version of Noether's theorem, or the symmetry-equals-invariant theorem. Next we use the general Lie transform theory to derive Deprit's perturbation theory. We illustrate this perturbation theory by application to two well-known problems in classical mechanics. Finally we present a chapter on conventions. There are many ways to develop Lie transforms. The last chapter explains the reasons for the choices made here.

  9. k-Symplectic Lie systems: theory and applications

    Science.gov (United States)

    de Lucas, J.; Vilariño, S.

    2015-03-01

    A Lie system is a system of first-order ordinary differential equations describing the integral curves of a t-dependent vector field taking values in a finite-dimensional real Lie algebra of vector fields: a so-called Vessiot-Guldberg Lie algebra. We suggest the definition of a particular class of Lie systems, the k-symplectic Lie systems, admitting a Vessiot-Guldberg Lie algebra of Hamiltonian vector fields with respect to the presymplectic forms of a k-symplectic structure. We devise new k-symplectic geometric methods to study their superposition rules, t-independent constants of motion and general properties. Our results are illustrated through examples of physical and mathematical interest. As a byproduct, we find a new interesting setting of application of the k-symplectic geometry: systems of first-order ordinary differential equations.

  10. Applied discrete-time queues

    CERN Document Server

    Alfa, Attahiru S

    2016-01-01

    This book introduces the theoretical fundamentals for modeling queues in discrete-time, and the basic procedures for developing queuing models in discrete-time. There is a focus on applications in modern telecommunication systems. It presents how most queueing models in discrete-time can be set up as discrete-time Markov chains. Techniques such as matrix-analytic methods (MAM) that can used to analyze the resulting Markov chains are included. This book covers single node systems, tandem system and queueing networks. It shows how queues with time-varying parameters can be analyzed, and illustrates numerical issues associated with computations for the discrete-time queueing systems. Optimal control of queues is also covered. Applied Discrete-Time Queues targets researchers, advanced-level students and analysts in the field of telecommunication networks. It is suitable as a reference book and can also be used as a secondary text book in computer engineering and computer science. Examples and exercises are includ...

  11. Mei Symmetry and Lie Symmetry of Relativistic Hamiltonian System

    Institute of Scientific and Technical Information of China (English)

    FANG Jian-Hui; YAN Xiang-Hong; LI Hong; CHEN Pei-Sheng

    2004-01-01

    The Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are studied. The definition and criterion of the Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are given. The relationship between them is found. The conserved quantities which the Mei symmetry and the Lie symmetry lead to are obtained.An example is given to illustrate the application of the result.

  12. Magnetic pseudo-differential Weyl calculus on nilpotent Lie groups

    CERN Document Server

    Beltita, Ingrid

    2009-01-01

    We develop a pseudo-differential Weyl calculus on nilpotent Lie groups which allows one to deal with magnetic perturbations of right invariant vector fields. For this purpose we investigate an infinite-dimensional Lie group constructed as the semidirect product of a nilpotent Lie grup and an appropriate function space thereon. We single out an appropriate coadjoint orbit in the semidirect product and construct our pseudo-differential calculus as a Weyl quantization of that orbit.

  13. Lie symmetries and invariants of constrained Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    Liu Rong-Wan; Chen Li-Qun

    2004-01-01

    According to the theory of the invariance of ordinary differential equations under the infinitesimal transformations of group, the relations between Lie symmetries and invariants of the mechanical system with a singular Lagrangian are investigated in phase space. New dynamical equations of the system are given in canonical form and the determining equations of Lie symmetry transformations are derived. The proposition about the Lie symmetries and invariants are presented. An example is given to illustrate the application of the result in this paper.

  14. A new kind of graded Lie algebra and parastatistical supersymmetry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper the usual Z2 graded Lie algebra is generalized to a new form, which may be called Z2,2 graded Lie algebra. It is shown that there exist close connections between the Z2,2 graded Lie algebra and parastatistics, so the Z2,2 can be used to study and analyse various symmetries and supersymmetries of the paraparticle systems.

  15. ON THE NOETHER SYMMETRY AND LIE SYMMETRY OF MECHANICAL SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    梅凤翔; 郑改华

    2002-01-01

    The Noether symmetry is an invariance of Hamilton action under infinitesimal transformations of time and the coordinates. The Lie symmetry is an invariance of the differential equations of motion under the transformations. In this paper, the relation between these two symmetries is proved definitely and firstly for mechanical systems. The results indicate that all the Noether symmetries are Lie symmetries for Lagrangian systems meanwhile a Noether symmetry is a Lie symmetry for the general holonomic or nonholonomic systems provided that some conditions hold.

  16. Noether-Lie Symmetry of Generalized Classical Mechanical Systems

    Institute of Scientific and Technical Information of China (English)

    JIA Wen-Zhi; ZHANG Xiao-Ni; WANG Shun-Jin; FANG Jian-Hui; WANG Peng; DING Ning

    2008-01-01

    In this paper, the Noether-Lie symmetry and conserved quantities of generalized classical mechanical system are studied. The definition and the criterion of the Noether Lie symmetry for the system under the general infinitesimal transformations of groups are given. The Noether conserved quantity and the Hojman conserved quantity deduced from the Noether-Lie symmetry are obtained. An example is given to illustrate the application of the results.

  17. Sectional and Ricci Curvature for Three-Dimensional Lie Groups

    Directory of Open Access Journals (Sweden)

    Gerard Thompson

    2016-01-01

    Full Text Available Formulas for the Riemann and Ricci curvature tensors of an invariant metric on a Lie group are determined. The results are applied to a systematic study of the curvature properties of invariant metrics on three-dimensional Lie groups. In each case the metric is reduced by using the automorphism group of the associated Lie algebra. In particular, the maximum and minimum values of the sectional curvature function are determined.

  18. The index of centralizers of elements of reductive Lie algebras

    CERN Document Server

    Charbonnel, Jean-Yves

    2010-01-01

    For a finite dimensional complex Lie algebra, its index is the minimal dimension of stabilizers for the coadjoint action. A famous conjecture due to Elashvili says that the index of the centralizer of an element of a reductive Lie algebra is equal to the rank. That conjecture caught attention of several Lie theorists for years. In this paper we give an almost general proof of that conjecture.

  19. Boolean-Lie algebras and the Leibniz rule

    Energy Technology Data Exchange (ETDEWEB)

    Bazso, Fueloep [KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences, PO Box 49, H-1525 Budapest (Hungary); Labos, Elemer [Neurobiology Research Group, United Research Organization of the Hungarian Academy of Sciences and Semmelweis University, H-1450 Budapest, PO Box 95 (Hungary)

    2006-06-02

    Using internal negations acting on Boolean functions, the notion of Boolean-Lie algebra is introduced. The underlying Lie product is the Boolean analogue of the Poisson bracket. The structure of a Boolean-Lie algebra is determined; it turns out to be solvable, but not nilpotent. We prove that the adjoint representation of an element of the Boolean-Lie algebra acts as a derivative operator on the space of Boolean functions. The adjoint representation is related to the previously known concept of the sensitivity function. Using the notion of adjoint representation we give the definition of a temporal derivative applicable to iterative dynamics of Boolean mappings.

  20. The Lie algebra of infinitesimal symmetries of nonlinear diffusion equations

    NARCIS (Netherlands)

    Kersten, Paul H.M.; Gragert, Peter K.H.

    1983-01-01

    By using developed software for solving overdetermined systems of partial differential equations, the authors establish the complete Lie algebra of infinitesimal symmetries of nonlinear diffusion equations.

  1. The structure of split regular BiHom-Lie algebras

    Science.gov (United States)

    Calderón, Antonio J.; Sánchez, José M.

    2016-12-01

    We introduce the class of split regular BiHom-Lie algebras as the natural extension of the one of split Hom-Lie algebras and so of split Lie algebras. We show that an arbitrary split regular BiHom-Lie algebra L is of the form L = U +∑jIj with U a linear subspace of a fixed maximal abelian subalgebra H and any Ij a well described (split) ideal of L, satisfying [Ij ,Ik ] = 0 if j ≠ k. Under certain conditions, the simplicity of L is characterized and it is shown that L is the direct sum of the family of its simple ideals.

  2. Construction of the elliptic Gaudin system based on Lie algebra

    Institute of Scientific and Technical Information of China (English)

    CAO Li-ke; LIANG Hong; PENG Dan-tao; YANG Tao; YUE Rui-hong

    2007-01-01

    Gaudin model is a very important integrable model in both quantum field theory and condensed matter physics.The integrability of Gaudin models is related to classical r-matrices of simple Lie algebras and semi-simple Lie algebra.Since most of the constructions of Gaudin models works concerned mainly on rational and trigonometric Gaudin algebras or just in a particular Lie algebra as an alternative to the matrix entry calculations often presented, in this paper we give our calculations in terms of a basis of the typical Lie algebra, An, Bn, Cn, Dn, and we calculate a classical r-matrix for the elliptic Gaudin system with spin.

  3. On Integrable Roots in Split Lie Triple Systems

    Institute of Scientific and Technical Information of China (English)

    A.J.CALDER(O)N MART(I)N

    2009-01-01

    We focus on the notion of an integrable root in the framework of split Lie triple systems T with a coherent 0-root space. As a main result, it is shown that if T has all its nonzero roots integrable, then its standard embedding is a split Lie algebra having all its nonzero roots integrable. As a consequence, a local finiteness theorem for split Lie triple systems, saying that whenever all nonzero roots of T are integrable then T is locally finite, is stated. Finally, a classification theorem for split simple Lie triple systems having all its nonzero roots integrable is given.

  4. Optimal Control Theory on almost-Lie Algebroids

    CERN Document Server

    Jozwikowski, Michal

    2011-01-01

    We extend the Pontryagin Maximum Principle (PMP) to the geometric setting of almost-Lie (AL) algebroids -- objects which generalize Lie algebroids. The result may be understood as a very general reduction scheme for optimal control problems (OCPs). It covers the standard PMP, as well as gives necessary optimality conditions for symmetric OCPs on Lie groups, principal bundles, and Lie groupoids. We do not assume the symmetry of boundary conditions. The ideas are based on a very general concept of homotopy of admissible paths on AL algebroids. Our framework works for OCPs with fixed-end-points and general boundary conditions.

  5. 3-Lie bialgebras (Lb,Cd and (Lb,Ce

    Directory of Open Access Journals (Sweden)

    Bai Ruipu

    2016-05-01

    Full Text Available Four dimensional $3$-Lie coalgebras with two-dimensional derived algebras, and four-dimensional $3$-Lie bialgebras of type $(L_b, C_c$ are classified. It is proved that there exist three classes of four dimensional $3$-Lie coalgebras with two-dimensional derived algebra which are $(L, C_{c_i}$, $i=1, 2, 3$ (Lemma 3.1, and ten classes of four dimensional $3$-Lie bialgebras of type $(L_b, C_c$ (Theorem 3.2.

  6. Time-discrete higher order ALE formulations: a priori error analysis

    KAUST Repository

    Bonito, Andrea

    2013-03-16

    We derive optimal a priori error estimates for discontinuous Galerkin (dG) time discrete schemes of any order applied to an advection-diffusion model defined on moving domains and written in the Arbitrary Lagrangian Eulerian (ALE) framework. Our estimates hold without any restrictions on the time steps for dG with exact integration or Reynolds\\' quadrature. They involve a mild restriction on the time steps for the practical Runge-Kutta-Radau methods of any order. The key ingredients are the stability results shown earlier in Bonito et al. (Time-discrete higher order ALE formulations: stability, 2013) along with a novel ALE projection. Numerical experiments illustrate and complement our theoretical results. © 2013 Springer-Verlag Berlin Heidelberg.

  7. What Lies Below a Martian Ice Cap

    Science.gov (United States)

    2008-01-01

    for the north polar layered deposits. BU stands for basal unit, an ice-sand deposit that lies beneath parts of the north polar layered deposits. The Shallow Radar instrument was provided by the Italian Space Agency. Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

  8. Variational discretizations for the dynamics of fluid-conveying flexible tubes

    Science.gov (United States)

    Gay-Balmaz, François; Putkaradze, Vakhtang

    2016-11-01

    We derive a variational approach for discretizing fluid-structure interactions, with a particular focus on the dynamics of fluid-conveying elastic tubes. Our method is based on a discretization of the fluid's back-to-labels map and a Lie group discretization of the tube's variables, coupled with an appropriately formulated discrete version of the fluid conservation law. This approach allows the development of geometric numerical schemes for the dynamics of fluid-conveying collapsible tubes, which preserve several intrinsic geometric properties of the continuous system, such as symmetries and symplecticity. In addition, our approach can also be used to derive simplified, but geometrically consistent, low-component models for further analytical and numerical analysis of the system. xml:lang="fr"

  9. Classical r-matrices of real low-dimensional Jacobi-Lie bialgebras and their Jacobi-Lie groups

    OpenAIRE

    Rezaei-Aghdam, A.; Sephid, M.

    2014-01-01

    In this research we obtain the classical r-matrices of real two and three dimensional Jacobi-Lie bialgebras. In this way, we classify all non-isomorphic real two and three dimensional coboundary Jacobi-Lie bialgebras and their types (triangular and quasitriangular). Also, we obtain the generalized Sklyanin bracket formula by use of which, we calculate the Jacobi structures on the related Jacobi-Lie groups. Finally, we present a new method for constructing classical integrable systems using co...

  10. Discrete Curvature Theories and Applications

    KAUST Repository

    Sun, Xiang

    2016-08-25

    Discrete Di erential Geometry (DDG) concerns discrete counterparts of notions and methods in di erential geometry. This thesis deals with a core subject in DDG, discrete curvature theories on various types of polyhedral surfaces that are practically important for free-form architecture, sunlight-redirecting shading systems, and face recognition. Modeled as polyhedral surfaces, the shapes of free-form structures may have to satisfy di erent geometric or physical constraints. We study a combination of geometry and physics { the discrete surfaces that can stand on their own, as well as having proper shapes for the manufacture. These proper shapes, known as circular and conical meshes, are closely related to discrete principal curvatures. We study curvature theories that make such surfaces possible. Shading systems of freeform building skins are new types of energy-saving structures that can re-direct the sunlight. From these systems, discrete line congruences across polyhedral surfaces can be abstracted. We develop a new curvature theory for polyhedral surfaces equipped with normal congruences { a particular type of congruences de ned by linear interpolation of vertex normals. The main results are a discussion of various de nitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula. In addition to architecture, we consider the role of discrete curvatures in face recognition. We use geometric measure theory to introduce the notion of asymptotic cones associated with a singular subspace of a Riemannian manifold, which is an extension of the classical notion of asymptotic directions. We get a simple expression of these cones for polyhedral surfaces, as well as convergence and approximation theorems. We use the asymptotic cones as facial descriptors and demonstrate the

  11. Particulate export vs lateral advection in the Antarctic Polar Front (Southern Pacific Ocean)

    Science.gov (United States)

    Tesi, T.; Langone, L.; Ravaioli, M.; Capotondi, L.; Giglio, F.

    2012-04-01

    The overarching goal of our study was to describe and quantify the influence of lateral advection relative to the vertical export in the Antarctic Polar Front (Southern Pacific Ocean). In areas where lateral advection of particulate material is significant, budgets of bioactive elements can be inaccurate if fluxes through the water column and to the seabed are exclusively interpreted as passive sinking of particles. However, detailed information on the influence of lateral advection in the water column in the southern ocean is lacking. With this in mind, our study focused between the twilight zone (i.e. mesopelagic) and the benthic nepheloid layer to understand the relative importance of lateral flux with increasing water depth. Measurements were performed south of the Antarctic Polar Front for 1 year (January 10th 1999-January 3rd 2000) at 900, 1300, 2400, and 3700 m from the sea surface. The study was carried out using a 3.5 km long mooring line instrumented with sediment traps, current meters and sensors of temperature and conductivity. Sediment trap samples were characterized via several parameters including total mass flux, elemental composition (organic carbon, total nitrogen, biogenic silica, and calcium carbonate), concentration of metals (aluminum, iron, barium, and manganese), 210Pb activity, and foraminifera taxonomy. High fluxes of biogenic particles were observed in both summer 1999 and 2000 as a result of seasonal algal blooms associated with sea ice retreat and water column stratification. During no-productive periods, several high energy events occurred and resulted in advecting resuspended biogenic particles from flat-topped summits of the Pacific Antarctic Ridge. Whereas the distance between seabed and uppermost sediment traps was sufficient to avoid lateral advection processes, resuspension was significant in the lowermost sediment traps accounting for ~60 and ~90% of the material caught at 2400 and 3700 m, respectively. Samples collected during

  12. SEBAL-A: A Remote Sensing ET Algorithm that Accounts for Advection with Limited Data. Part I: Development and Validation

    Directory of Open Access Journals (Sweden)

    Mcebisi Mkhwanazi

    2015-11-01

    Full Text Available The Surface Energy Balance Algorithm for Land (SEBAL is one of the remote sensing (RS models that are increasingly being used to determine evapotranspiration (ET. SEBAL is a widely used model, mainly due to the fact that it requires minimum weather data, and also no prior knowledge of surface characteristics is needed. However, it has been observed that it underestimates ET under advective conditions due to its disregard of advection as another source of energy available for evaporation. A modified SEBAL model was therefore developed in this study. An advection component, which is absent in the original SEBAL, was introduced such that the energy available for evapotranspiration was a sum of net radiation and advected heat energy. The improved SEBAL model was termed SEBAL-Advection or SEBAL-A. An important aspect of the improved model is the estimation of advected energy using minimal weather data. While other RS models would require hourly weather data to be able to account for advection (e.g., METRIC, SEBAL-A only requires daily averages of limited weather data, making it appropriate even in areas where weather data at short time steps may not be available. In this study, firstly, the original SEBAL model was evaluated under advective and non-advective conditions near Rocky Ford in southeastern Colorado, a semi-arid area where afternoon advection is common occurrence. The SEBAL model was found to incur large errors when there was advection (which was indicated by higher wind speed and warm and dry air. SEBAL-A was then developed and validated in the same area under standard surface conditions, which were described as healthy alfalfa with height of 40–60 cm, without water-stress. ET values estimated using the original and modified SEBAL were compared to large weighing lysimeter-measured ET values. When the SEBAL ET was compared to SEBAL-A ET values, the latter showed improved performance, with the ET Mean Bias Error (MBE reduced from −17

  13. On the Correct Use of Statistical Tests: Reply to "Lies, damned lies and statistics (in Geology)"

    CERN Document Server

    Sornette, D

    2010-01-01

    In a recent Forum in EOS entitled "Lies, damned lies and statistics (in Geology)", Vermeesch (2009) claims that "statistical significant is not the same as geological significant", in other words, statistical tests may be misleading. In complete contradiction, we affirm that statistical tests are always informative. We trace the erroneous claim of Vermeesch (2009) to a mistake in the interpretation of the chi-square test. Furthermore, using the same catalog of 118,415 earthquakes of magnitude 4 or greater and occurring between Friday 1st January 1999 and Thursday, 1 January 2009 (USGS, http://earthquake.usgs.gov), we show that the null hypothesis that "the occurrence of earthquakes does not depend on the day of the week" cannot be rejected (p-value equal to p=0.46), when taking into account the two well-known effects of (i) catalog incompleteness and (ii) aftershock clustering. This corrects the p-value p=4.5 10^{-18} found by P. Vermeesch (2009), whose implementation of the chi-square test assumes that the 1...

  14. Analysis of Discrete Mittag - Leffler Functions

    Directory of Open Access Journals (Sweden)

    N. Shobanadevi

    2015-03-01

    Full Text Available Discrete Mittag - Leffler functions play a major role in the development of the theory of discrete fractional calculus. In the present article, we analyze qualitative properties of discrete Mittag - Leffler functions and establish sufficient conditions for convergence, oscillation and summability of the infinite series associated with discrete Mittag - Leffler functions.

  15. Lie Algebroids in Classical Mechanics and Optimal Control

    Directory of Open Access Journals (Sweden)

    Eduardo Martínez

    2007-03-01

    Full Text Available We review some recent results on the theory of Lagrangian systems on Lie algebroids. In particular we consider the symplectic and variational formalism and we study reduction. Finally we also consider optimal control systems on Lie algebroids and we show how to reduce Pontryagin maximum principle.

  16. Quantum Lie algebras of type A$_{n}$

    CERN Document Server

    Sudbery, A I

    1995-01-01

    It is shown that the quantised enveloping algebra of sl(n) contains a quantum Lie algebra, defined by means of axioms similar to Woronowicz's. This gives rise to Lie algebra-like generators and relations for the locally finite part of the quantised enveloping algebra, and suggests a canonical Poincare-Birkhoff-Witt basis.

  17. Poisson Manifolds, Lie Algebroids, Modular Classes: a Survey

    Directory of Open Access Journals (Sweden)

    Yvette Kosmann-Schwarzbach

    2008-01-01

    Full Text Available After a brief summary of the main properties of Poisson manifolds and Lie algebroids in general, we survey recent work on the modular classes of Poisson and twisted Poisson manifolds, of Lie algebroids with a Poisson or twisted Poisson structure, and of Poisson-Nijenhuis manifolds. A review of the spinor approach to the modular class concludes the paper.

  18. Linear algebra meets Lie algebra: the Kostant-Wallach theory

    OpenAIRE

    Shomron, Noam; Parlett, Beresford N.

    2008-01-01

    In two languages, Linear Algebra and Lie Algebra, we describe the results of Kostant and Wallach on the fibre of matrices with prescribed eigenvalues of all leading principal submatrices. In addition, we present a brief introduction to basic notions in Algebraic Geometry, Integrable Systems, and Lie Algebra aimed at specialists in Linear Algebra.

  19. Structures of W(2.2 Lie conformal algebra

    Directory of Open Access Journals (Sweden)

    Yuan Lamei

    2016-01-01

    . In this paper, we study conformal derivations, central extensions and conformal modules for this Lie conformal algebra. Also, we compute the cohomology of this Lie conformal algebra with coefficients in its modules. In particular, we determine its cohomology with trivial coefficients both for the basic and reduced complexes.

  20. Construction of Lie Superalgebras from Triple Product Systems

    OpenAIRE

    Okubo, Susumu

    2003-01-01

    Any simple Lie superalgebras over the complex field can be constructed from some triple systems. Examples of Lie superalgebras $D(2,1;\\alpha)$, G(3) and F(4) are given by utilizing a general construction method based upon $(-1,-1)$ balanced Freudenthal-Kantor triple system.