Some problems of dynamical systems on three dimensional manifolds
International Nuclear Information System (INIS)
Dong Zhenxie.
1985-08-01
It is important to study the dynamical systems on 3-dimensional manifolds, its importance is showing up in its close relation with our life. Because of the complication of topological structure of Dynamical systems on 3-dimensional manifolds, generally speaking, the search for 3-dynamical systems is not easier than 2-dynamical systems. This paper is a summary of the partial result of dynamical systems on 3-dimensional manifolds. (author)
PREFACE: Dynamics of low-dimensional systems Dynamics of low-dimensional systems
Bernasconi, M.; Miret-Artés, S.; Toennies, J. P.
2012-03-01
With the development of techniques for high-resolution inelastic helium atom scattering (HAS), electron scattering (EELS) and neutron spin echo spectroscopy, it has become possible, within approximately the last thirty years, to measure the dispersion curves of surface phonons in insulators, semiconductors and metals. In recent years, the advent of new experimental techniques such as 3He spin-echo spectroscopy, scanning inelastic electron tunnel spectroscopy, inelastic x-ray scattering spectroscopy and inelastic photoemission have extended surface phonon spectroscopy to a variety of systems. These include ultra-thin metal films, adsorbates at surface and elementary processes where surface phonons play an important role. Other important directions have been actively pursued in the past decade: the dynamics of stepped surfaces and clusters grown on metal surfaces, due to their relevance in many dynamical and chemical processes at surfaces, including heterogeneous catalysis; clusters; diffusion etc. The role of surface effects in these processes has been conjectured since the early days of surface dynamics, although only now is the availability of ab initio approaches providing those conjectures with a microscopic basis. Last but not least, the investigation of non-adiabatic effects, originating for instance from the hybridization (avoided crossing) of the surface phonons branches with the quasi 1D electron-hole excitation branch, is also a challenging new direction. Furthermore, other elementary oscillations such as surface plasmons are being actively investigated. The aforementioned experimental breakthroughs have been accompanied by advances in the theoretical study of atom-surface interaction. In particular, in the past decade first principles calculations based on density functional perturbation theory have boosted the theoretical study of the dynamics of low-dimensional systems. Phonon dispersion relations of clean surfaces, the dynamics of adsorbates, and the
Blended particle filters for large-dimensional chaotic dynamical systems
Majda, Andrew J.; Qi, Di; Sapsis, Themistoklis P.
2014-01-01
A major challenge in contemporary data science is the development of statistically accurate particle filters to capture non-Gaussian features in large-dimensional chaotic dynamical systems. Blended particle filters that capture non-Gaussian features in an adaptively evolving low-dimensional subspace through particles interacting with evolving Gaussian statistics on the remaining portion of phase space are introduced here. These blended particle filters are constructed in this paper through a mathematical formalism involving conditional Gaussian mixtures combined with statistically nonlinear forecast models compatible with this structure developed recently with high skill for uncertainty quantification. Stringent test cases for filtering involving the 40-dimensional Lorenz 96 model with a 5-dimensional adaptive subspace for nonlinear blended filtering in various turbulent regimes with at least nine positive Lyapunov exponents are used here. These cases demonstrate the high skill of the blended particle filter algorithms in capturing both highly non-Gaussian dynamical features as well as crucial nonlinear statistics for accurate filtering in extreme filtering regimes with sparse infrequent high-quality observations. The formalism developed here is also useful for multiscale filtering of turbulent systems and a simple application is sketched below. PMID:24825886
Oscillation of Two-Dimensional Neutral Delay Dynamic Systems
Directory of Open Access Journals (Sweden)
Xinli Zhang
2013-01-01
Full Text Available We consider a class of nonlinear two-dimensional dynamic systems of the neutral type (x(t-a(tx(τ1(tΔ=p(tf1(y(t, yΔ(t=-q(tf2(x(τ2(t. We obtain sufficient conditions for all solutions of the system to be oscillatory. Our oscillation results when a(t=0 improve the oscillation results for dynamic systems on time scales that have been established by Fu and Lin (2010, since our results do not restrict to the case where f(u=u. Also, as a special case when =ℝ, our results do not require an to be a positive real sequence. Some examples are given to illustrate the main results.
Gauge theory for finite-dimensional dynamical systems
International Nuclear Information System (INIS)
Gurfil, Pini
2007-01-01
Gauge theory is a well-established concept in quantum physics, electrodynamics, and cosmology. This concept has recently proliferated into new areas, such as mechanics and astrodynamics. In this paper, we discuss a few applications of gauge theory in finite-dimensional dynamical systems. We focus on the concept of rescriptive gauge symmetry, which is, in essence, rescaling of an independent variable. We show that a simple gauge transformation of multiple harmonic oscillators driven by chaotic processes can render an apparently ''disordered'' flow into a regular dynamical process, and that there exists a strong connection between gauge transformations and reduction theory of ordinary differential equations. Throughout the discussion, we demonstrate the main ideas by considering examples from diverse fields, including quantum mechanics, chemistry, rigid-body dynamics, and information theory
Dynamic screening and electron dynamics in low-dimensional metal systems
International Nuclear Information System (INIS)
Silkin, V.M.; Quijada, M.; Vergniory, M.G.; Alducin, M.; Borisov, A.G.; Diez Muino, R.; Juaristi, J.I.; Sanchez-Portal, D.; Chulkov, E.V.; Echenique, P.M.
2007-01-01
Recent advances in the theoretical description of dynamic screening and electron dynamics in metallic media are reviewed. The time-dependent building-up of screening in different situations is addressed. Perturbative and non-perturbative theories are used to study electron dynamics in low-dimensional systems, such as metal clusters, image states, surface states and quantum wells. Modification of the electronic lifetimes due to confinement effects is analyzed as well
Nambu-Poisson reformulation of the finite dimensional dynamical systems
International Nuclear Information System (INIS)
Baleanu, D.; Makhaldiani, N.
1998-01-01
A system of nonlinear ordinary differential equations which in a particular case reduces to Volterra's system is introduced. We found in two simplest cases the complete sets of the integrals of motion using Nambu-Poisson reformulation of the Hamiltonian dynamics. In these cases we have solved the systems by quadratures
Geometric Methods for Infinite-Dimensional Dynamical Systems
2012-08-27
thermohaline circulation due to sea ice processes Qiliang Wu (University of Minnesota) Dynamics near Turing patterns in RD systems ...of them covering multiple themes. Ample time (90 minutes) was devoted to the poster session, so that participants could circulate to all of the
Adiabatic dynamics of one-dimensional classical Hamiltonian dissipative systems
Pritula, G. M.; Petrenko, E. V.; Usatenko, O. V.
2018-02-01
A linearized plane pendulum with the slowly varying mass and length of string and the suspension point moving at a slowly varying speed is presented as an example of a simple 1D mechanical system described by the generalized harmonic oscillator equation, which is a basic model in discussion of the adiabatic dynamics and geometric phase. The expression for the pendulum geometric phase is obtained by three different methods. The pendulum is shown to be canonically equivalent to the damped harmonic oscillator. This supports the mathematical conclusion, not widely accepted in physical community, of no difference between the dissipative and Hamiltonian 1D systems.
Directory of Open Access Journals (Sweden)
D. A. Fetisov
2015-01-01
Full Text Available The controllability conditions are well known if we speak about linear stationary systems: a linear stationary system is controllable if and only if the dimension of the state vector is equal to the rank of the controllability matrix. The concept of the controllability matrix is extended to affine systems, but relations between affine systems controllability and properties of this matrix are more complicated. Various controllability conditions are set for affine systems, but they deal as usual either with systems of some special form or with controllability in some small neighborhood of the concerned point. An affine system is known to be controllable if the system is equivalent to a system of a canonical form, which is defined and regular in the whole space of states. In this case, the system is said to be feedback linearizable in the space of states. However there are examples, which illustrate that a system can be controllable even if it is not feedback linearizable in any open subset in the space of states. In this article we deal with such systems.Affine systems with two-dimensional control are considered. The system in question is assumed to be equivalent to a system of a quasicanonical form with two-dimensional zero dynamics which is defined and regular in the whole space of states. Therefore the controllability of the original system is equivalent to the controllability of the received system of a quasicanonical form. In this article the sufficient condition for an available solution of the terminal problem is proven for systems of a quasicanonical form with two-dimensional control and two-dimensional zero dynamics. The condition is valid in the case of an arbitrary time interval and arbitrary initial and finite states of the system. Therefore the controllability condition is set for systems of a quasicanonical form with two-dimensional control and two-dimensional zero dynamics. An example is given which illustrates how the proved
An algorithm for engineering regime shifts in one-dimensional dynamical systems
Tan, James P. L.
2018-01-01
Regime shifts are discontinuous transitions between stable attractors hosting a system. They can occur as a result of a loss of stability in an attractor as a bifurcation is approached. In this work, we consider one-dimensional dynamical systems where attractors are stable equilibrium points. Relying on critical slowing down signals related to the stability of an equilibrium point, we present an algorithm for engineering regime shifts such that a system may escape an undesirable attractor into a desirable one. We test the algorithm on synthetic data from a one-dimensional dynamical system with a multitude of stable equilibrium points and also on a model of the population dynamics of spruce budworms in a forest. The algorithm and other ideas discussed here contribute to an important part of the literature on exercising greater control over the sometimes unpredictable nature of nonlinear systems.
Instantaneous normal modes and cooperative dynamics in a quasi-two-dimensional system of particles
Zangi, R; Rice, SA
2004-01-01
In recent molecular dynamics simulations [Phys. Rev. E 2003, 68, 061508] we found that the deviation of the single-particle displacement distribution from Gaussian form is a characteristic that is common to all phases of a system confined to a quasi-two-dimensional geometry (liquid, hexatic, and
Complete set of representations for dissipative chaotic three-dimensional dynamical systems.
Cross, Daniel J; Gilmore, R
2010-11-01
Embeddings are diffeomorphisms between some dynamical phase space and a reconstructed image. Different embeddings may or may not be equivalent under isotopy. We regard embeddings as representations of the dynamical phase space. We determine the topological labels required to distinguish inequivalent representations of three-dimensional dissipative dynamical systems when the embeddings are into R(k), k=3,4,5,…. Three representation labels are required for embeddings into R³, and only one is required in R⁴. In R⁵ there is a single "universal" representation.
Dynamics of interface in three-dimensional anisotropic bistable reaction-diffusion system
International Nuclear Information System (INIS)
He Zhizhu; Liu, Jing
2010-01-01
This paper presents a theoretical investigation of dynamics of interface (wave front) in three-dimensional (3D) reaction-diffusion (RD) system for bistable media with anisotropy constructed by means of anisotropic surface tension. An equation of motion for the wave front is derived to carry out stability analysis of transverse perturbations, which discloses mechanism of pattern formation such as labyrinthine in 3D bistable media. Particularly, the effects of anisotropy on wave propagation are studied. It was found that, sufficiently strong anisotropy can induce dynamical instabilities and lead to breakup of the wave front. With the fast-inhibitor limit, the bistable system can further be described by a variational dynamics so that the boundary integral method is adopted to study the dynamics of wave fronts.
International Nuclear Information System (INIS)
Thakur, Anmol; Agarwal, Amit; Sachdeva, Rashi
2017-01-01
We study the density–density response function of a collection of charged massive Dirac particles and present analytical expressions for the dynamical polarization function in one, two and three dimensions. The polarization function is then used to find the dispersion of the plasmon modes, and electrostatic screening of Coulomb interactions within the random phase approximation. We find that for massive Dirac systems, the oscillating screened potential (or density) decays as r −2 and r −3 in two and three dimensions respectively, and as r −1 for one dimensional non-interacting systems. However for massless Dirac systems there is no electrostatic screening or Friedel oscillation in one dimension, and the oscillating screened potential decays as r −3 and r −4 , in two and three dimensions respectively. Our analytical results for the polarization function will be useful for exploring the physics of massive and massless Dirac electrons in different experimental systems with varying dimensionality. (paper)
Geraci, Joseph; Dharsee, Moyez; Nuin, Paulo; Haslehurst, Alexandria; Koti, Madhuri; Feilotter, Harriet E; Evans, Ken
2014-03-01
We introduce a novel method for visualizing high dimensional data via a discrete dynamical system. This method provides a 2D representation of the relationship between subjects according to a set of variables without geometric projections, transformed axes or principal components. The algorithm exploits a memory-type mechanism inherent in a certain class of discrete dynamical systems collectively referred to as the chaos game that are closely related to iterative function systems. The goal of the algorithm was to create a human readable representation of high dimensional patient data that was capable of detecting unrevealed subclusters of patients from within anticipated classifications. This provides a mechanism to further pursue a more personalized exploration of pathology when used with medical data. For clustering and classification protocols, the dynamical system portion of the algorithm is designed to come after some feature selection filter and before some model evaluation (e.g. clustering accuracy) protocol. In the version given here, a univariate features selection step is performed (in practice more complex feature selection methods are used), a discrete dynamical system is driven by this reduced set of variables (which results in a set of 2D cluster models), these models are evaluated for their accuracy (according to a user-defined binary classification) and finally a visual representation of the top classification models are returned. Thus, in addition to the visualization component, this methodology can be used for both supervised and unsupervised machine learning as the top performing models are returned in the protocol we describe here. Butterfly, the algorithm we introduce and provide working code for, uses a discrete dynamical system to classify high dimensional data and provide a 2D representation of the relationship between subjects. We report results on three datasets (two in the article; one in the appendix) including a public lung cancer
First-passage dynamics of obstructed tracer particle diffusion in one-dimensional systems
Forsling, Robin; Sanders, Lloyd; Ambjörnsson, Tobias; Lizana, Ludvig
2014-01-01
The standard setup for single-file diffusion is diffusing particles in one dimension which cannot overtake each other, where the dynamics of a tracer (tagged) particle is of main interest. In this article we generalise this system and investigate first-passage properties of a tracer particle when flanked by crowder particles which may, besides diffuse, unbind (rebind) from (to) the one-dimensional lattice with rates $k_{\\rm off}$ ($k_{\\rm on}$). The tracer particle is restricted to diffuse wi...
Sternberg, Shlomo
2010-01-01
Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the
Rigid-flexible coupling dynamics of three-dimensional hub-beams system
International Nuclear Information System (INIS)
Liu Jinyang; Lu Hao
2007-01-01
In the previous research of the coupling dynamics of a hub-beam system, coupling between the rotational motion of hub and the torsion deformation of beam is not taken into account since the system undergoes planar motion. Due to the small longitudinal deformation, coupling between the rotational motion of hub and the longitudinal deformation of beam is also neglected. In this paper, rigid-flexible coupling dynamics is extended to a hub-beams system with three-dimensional large overall motion. Not only coupling between the large overall motion and the bending deformation, but also coupling between the large overall motion and the torsional deformation are taken into account. In case of temperature increase, the longitudinal deformation caused by the thermal expansion is significant, such that coupling between the large overall motion and the longitudinal deformation is also investigated. Combining the characteristics of the hybrid coordinate formulation and the absolute nodal coordinate formulation, the system generalized coordinates include the relative nodal displacement and the slope of each beam element with respect to the body-fixed frame of the hub, and the variables related to the spatial large overall motion of the hub and beams. Based on precise strain-displacement relation, the geometric stiffening effect is taken into account, and the rigid-flexible coupling dynamic equations are derived using velocity variational principle. Finite element method is employed for discretization. Simulation of a hub-beams system is used to show the coupling effect between the large overall motion and the torsional deformation as well as the longitudinal deformation. Furthermore, conservation of energy in case of free motion is shown to verify the formulation
Dynamics of pre-strained bi-material elastic systems linearized three-dimensional approach
Akbarov, Surkay D
2015-01-01
This book deals with dynamics of pre-stressed or pre-strained bi-material elastic systems consisting of stack of pre-stressed layers, stack of pre-stressed layers and pre-stressed half space (or half plane), stack of pre-stressed layers as well as absolute rigid foundation, pre-stressed compound solid and hollow cylinders and pre-stressed sandwich hollow cylinders. The problems considered in the book relate to the dynamics of a moving and oscillating moving load, forced vibration caused by linearly located or point located time-harmonic forces acting to the foregoing systems. Moreover, a considerable part of the book relate to the problems regarding the near surface, torsional and axisymmetric longitudinal waves propagation and dispersion in the noted above bi-material elastic systems. The book carries out the investigations within the framework of the piecewise homogeneous body model with the use of the Three-Dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies.
Directory of Open Access Journals (Sweden)
SERGIY KOZERENKO
2016-04-01
Full Text Available One feature of the famous Sharkovsky’s theorem is that it can be proved using digraphs of a special type (the so–called Markov graphs. The most general definition assigns a Markov graph to every continuous map from the topological graph to itself. We show that this definition is too broad, i.e. every finite digraph can be viewed as a Markov graph of some one–dimensional dynamical system on a tree. We therefore consider discrete analogues of Markov graphs for vertex maps on combinatorial trees and characterize all maps on trees whose discrete Markov graphs are of the following types: complete, complete bipartite, the disjoint union of cycles, with every arc being a loop.
Perturbation approach and the constant of motion for on-dimensional dynamical systems
International Nuclear Information System (INIS)
Lopez, G.
1991-11-01
A perturbation technic is used to find the constant of motion of a one-dimensional autonomous system. The convergence of the method is discussed through some examples. In addition, the approach is extended to one-dimensional non-autonomous systems where some examples are given
Quasiclassical methods for spin-charge coupled dynamics in low-dimensional systems
International Nuclear Information System (INIS)
Corini, Cosimo
2009-01-01
Spintronics is a new field of study whose broad aim is the manipulation of the spin degrees of freedom in solid state systems. One of its main goals is the realization of devices capable of exploiting, besides the charge, the carriers' - and possibly the nuclei's - spin. The presence of spin-orbit coupling in a system enables the spin and charge degrees of freedom to ''communicate'', a favorable situation if one is to realize such devices. More importantly, it offers the opportunity of doing so by relying solely on electric fields, whereas magnetic fields are otherwise required. Eminent examples of versatile systems with built-in and variously tunable spin-orbit interaction are two-dimensional electron - or hole - gases. The study of spin-charge coupled dynamics in such a context faces a large number of open questions, both of the fundamental and of the more practical type. To tackle the problem we rely on the quasiclassical formalism. This is an approximate quantum-field theoretical formulation with a solid microscopic foundation, perfectly suited for describing phenomena at the mesoscopic scale, and bearing a resemblance to standard Boltzmann theory which makes for physical transparency. Originally born to deal with transport in electron-phonon systems, we first generalize it to the case in which spin-orbit coupling is present, and then move on to apply it to specific situations and phenomena. Among these, to the description of the spin Hall effect and of voltage induced spin polarizations in two-dimensional electron gases under a variety of conditions - stationary or time-dependent, in the presence of magnetic and non-magnetic disorder, in the bulk or in confined geometries -, and to the problem of spin relaxation in narrow wires. (orig.)
Quasiclassical methods for spin-charge coupled dynamics in low-dimensional systems
Energy Technology Data Exchange (ETDEWEB)
Corini, Cosimo
2009-06-12
Spintronics is a new field of study whose broad aim is the manipulation of the spin degrees of freedom in solid state systems. One of its main goals is the realization of devices capable of exploiting, besides the charge, the carriers' - and possibly the nuclei's - spin. The presence of spin-orbit coupling in a system enables the spin and charge degrees of freedom to ''communicate'', a favorable situation if one is to realize such devices. More importantly, it offers the opportunity of doing so by relying solely on electric fields, whereas magnetic fields are otherwise required. Eminent examples of versatile systems with built-in and variously tunable spin-orbit interaction are two-dimensional electron - or hole - gases. The study of spin-charge coupled dynamics in such a context faces a large number of open questions, both of the fundamental and of the more practical type. To tackle the problem we rely on the quasiclassical formalism. This is an approximate quantum-field theoretical formulation with a solid microscopic foundation, perfectly suited for describing phenomena at the mesoscopic scale, and bearing a resemblance to standard Boltzmann theory which makes for physical transparency. Originally born to deal with transport in electron-phonon systems, we first generalize it to the case in which spin-orbit coupling is present, and then move on to apply it to specific situations and phenomena. Among these, to the description of the spin Hall effect and of voltage induced spin polarizations in two-dimensional electron gases under a variety of conditions - stationary or time-dependent, in the presence of magnetic and non-magnetic disorder, in the bulk or in confined geometries -, and to the problem of spin relaxation in narrow wires. (orig.)
Peng, NaiFu; Guan, Hui; Wu, ChuiJie
2016-04-01
In this paper, the theory of constructing optimal dynamical systems based on weighted residual presented by Wu & Sha is applied to three-dimensional Navier-Stokes equations, and the optimal dynamical system modeling equations are derived. Then the multiscale global optimization method based on coarse graining analysis is presented, by which a set of approximate global optimal bases is directly obtained from Navier-Stokes equations and the construction of optimal dynamical systems is realized. The optimal bases show good properties, such as showing the physical properties of complex flows and the turbulent vortex structures, being intrinsic to real physical problem and dynamical systems, and having scaling symmetry in mathematics, etc.. In conclusion, using fewer terms of optimal bases will approach the exact solutions of Navier-Stokes equations, and the dynamical systems based on them show the most optimal behavior.
Saso, Tetsuro; Kim, C. I.; Kasuya, Tadao
1983-06-01
Report is given on a computer simulation of the dynamical conductivity σ(ω) of one-dimensional disordered systems with up to 106 sites by MacKinnon’s method. A comparison is made with the asymptotically exact solution valid for weak disorder by Berezinskii.
Allaire, S E; Yates, S R; Ernst, F F; Gan, J
2002-01-01
There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models.
2015-12-04
with remarkable efficiency despite their exposure to “hot and wet” environmental conditions. This proposal seeks to develop instrumentation tailored...on solution processing. 1.1.2. Autonomous Systems. The systems described here are incredibly robust to a host of environmental conditions, both...static and dynamic. Since feedback can perturb the fragile quantum state of the system, a robust quantum dynamical system must avoid direct
Wavepacket dynamics in one-dimensional system with long-range correlated disorder
Yamada, Hiroaki S.
2018-03-01
We numerically investigate dynamical property in the one-dimensional tight-binding model with long-range correlated disorder having power spectrum 1 /fα (α: spectrum exponent) generated by Fourier filtering method. For relatively small α MSD) of the initially localized wavepacket shows ballistic spread and localizes as time elapses. It is shown that α-dependence of the dynamical localization length determined by the MSD exhibits a simple scaling law in the localization regime for the relatively weak disorder strength W. Furthermore, scaled MSD by the dynamical localization length almost obeys an universal function from the ballistic to the localization regime in the various combinations of the parameters α and W.
Stabilization of infinite dimensional port-Hamiltonian systems by nonlinear dynamic boundary control
Ramirez, Hector; Zwart, Hans; Le Gorrec, Yann
2017-01-01
The conditions for existence of solutions and stability, asymptotic and exponential, of a large class of boundary controlled systems on a 1D spatial domain subject to nonlinear dynamic boundary actuation are given. The consideration of such class of control systems is motivated by the use of
Di Liberto, Giovanni; Conte, Riccardo; Ceotto, Michele
2018-01-01
We extensively describe our recently established "divide-and-conquer" semiclassical method [M. Ceotto, G. Di Liberto, and R. Conte, Phys. Rev. Lett. 119, 010401 (2017)] and propose a new implementation of it to increase the accuracy of results. The technique permits us to perform spectroscopic calculations of high-dimensional systems by dividing the full-dimensional problem into a set of smaller dimensional ones. The partition procedure, originally based on a dynamical analysis of the Hessian matrix, is here more rigorously achieved through a hierarchical subspace-separation criterion based on Liouville's theorem. Comparisons of calculated vibrational frequencies to exact quantum ones for a set of molecules including benzene show that the new implementation performs better than the original one and that, on average, the loss in accuracy with respect to full-dimensional semiclassical calculations is reduced to only 10 wavenumbers. Furthermore, by investigating the challenging Zundel cation, we also demonstrate that the "divide-and-conquer" approach allows us to deal with complex strongly anharmonic molecular systems. Overall the method very much helps the assignment and physical interpretation of experimental IR spectra by providing accurate vibrational fundamentals and overtones decomposed into reduced dimensionality spectra.
Liu, Pengfei; Zhai, Wanming; Wang, Kaiyun
2016-11-01
For the long heavy-haul train, the basic principles of the inter-vehicle interaction and train-track dynamic interaction are analysed firstly. Based on the theories of train longitudinal dynamics and vehicle-track coupled dynamics, a three-dimensional (3-D) dynamic model of the heavy-haul train-track coupled system is established through a modularised method. Specifically, this model includes the subsystems such as the train control, the vehicle, the wheel-rail relation and the line geometries. And for the calculation of the wheel-rail interaction force under the driving or braking conditions, the large creep phenomenon that may occur within the wheel-rail contact patch is considered. For the coupler and draft gear system, the coupler forces in three directions and the coupler lateral tilt angles in curves are calculated. Then, according to the characteristics of the long heavy-haul train, an efficient solving method is developed to improve the computational efficiency for such a large system. Some basic principles which should be followed in order to meet the requirement of calculation accuracy are determined. Finally, the 3-D train-track coupled model is verified by comparing the calculated results with the running test results. It is indicated that the proposed dynamic model could simulate the dynamic performance of the heavy-haul train well.
Jellali, Nabiha; Najjar, Monia; Ferchichi, Moez; Rezig, Houria
2017-07-01
In this paper, a new two-dimensional spectral/spatial codes family, named two dimensional dynamic cyclic shift codes (2D-DCS) is introduced. The 2D-DCS codes are derived from the dynamic cyclic shift code for the spectral and spatial coding. The proposed system can fully eliminate the multiple access interference (MAI) by using the MAI cancellation property. The effect of shot noise, phase-induced intensity noise and thermal noise are used to analyze the code performance. In comparison with existing two dimensional (2D) codes, such as 2D perfect difference (2D-PD), 2D Extended Enhanced Double Weight (2D-Extended-EDW) and 2D hybrid (2D-FCC/MDW) codes, the numerical results show that our proposed codes have the best performance. By keeping the same code length and increasing the spatial code, the performance of our 2D-DCS system is enhanced: it provides higher data rates while using lower transmitted power and a smaller spectral width.
Dorozhkin, S. Â. I.; Kapustin, A. Â. A.; Dmitriev, I. Â. A.; Umansky, V.; von Klitzing, K.; Smet, J. H.
2017-10-01
We have studied the absorption of monochromatic microwave radiation in high-quality two-dimensional electron systems for the frequency span from 10 to 380 GHz using a bolometric method. For frequencies above 100 GHz the absorption exhibits an anomalous magnetic field dependence. Minima form at harmonics of the cyclotron resonance frequency. The results contrast previously reported data for other frequency ranges. Quasiclassical memory effects originating from the non-Markovian dynamics of electrons in a disorder potential containing short-range scatterers on top of a smooth potential background favorably account for the observed behavior.
Fu, Qiang; Zheng, Changjie
2014-01-01
A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.
Directory of Open Access Journals (Sweden)
Qiang Fu
2014-01-01
Full Text Available A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.
Static and dynamic properties of frictional phenomena in a one-dimensional system with randomness
International Nuclear Information System (INIS)
Kawaguchi, T.; Matsukawa, H.
1997-01-01
Static and dynamic frictional phenomena at the interface with random impurities are investigated in a two-chain model with incommensurate structure. Static frictional force is caused by the impurity pinning and/or by the pinning due to the regular potential, which is responsible for the breaking of analyticity transition for impurity-free cases. It is confirmed that the static frictional force is always finite in the presence of impurities, in contrast to the impurity-free system. The nature of impurity pinning is discussed in connection with that in density waves. The kinetic frictional force of a steady sliding state is also investigated numerically. The relationship between the sliding velocity dependence of the kinetic frictional force and the strength of impurity potential is discussed. copyright 1997 The American Physical Society
Spin temperatures under dynamic polarization in a one-dimensional system, the TANOL
International Nuclear Information System (INIS)
Barjhoux, Yves.
1974-01-01
A quantitative model of Tanol submitted to dynamic polarization has been developed. The spin systems are described using a network of interconnected reservoirs. The model involves six (or ten) Zeeman nuclear reservoirs mutually coupled by nuclear-nuclear dipole interactions and coupled to electron spins by hyperfine interactions. When the electronic line is saturated, different nuclear temperatures appear in the molecule. These temperatures have been calculated as a function of the magnetic field orientation against the crystallographic axes. Experimental results are correctly reproduced. A quantitative agreement is obtained for the anisotropy of total polarization. The calculation also shows that, in certain directions, positive and negative spin temperatures simultaneously appear, that explains the complex shape of the signals observed. Nuclear relaxation processes involving two electron spins of the same exchange chain are taken into account for the calculation. The different possible chain directions (a, a+c, or c vectors) were envisaged. Only the c-vector hypothesis succeeded in interpreting experimental results [fr
A three-dimensional autonomous nonlinear dynamical system modelling equatorial ocean flows
Ionescu-Kruse, Delia
2018-04-01
We investigate a nonlinear three-dimensional model for equatorial flows, finding exact solutions that capture the most relevant geophysical features: depth-dependent currents, poleward or equatorial surface drift and a vertical mixture of upward and downward motions.
International Nuclear Information System (INIS)
Wang, C.Y.
1985-01-01
A three-dimensional computer program for liner/non-linear, static/dynamic analyses of reactor-piping systems under various accident loads is described. In the analysis, the hydrodynamic calculation can be performed in the implicit or semi-implicit manner. The structure response can be calculated using either a purely explicit or implicit time-integration scheme. Coupling between the fluid and structure is achieved by utilizing either the implicit-explicit or implicit-implicit link. Thus, a wide range of piping safety problems can be analyzed by the suitable choice of options available in the hydrodynamics and structural analysis. In this paper, several salient features are presented. Sample problems illustrating the versatility of the program are given. The results are discussed in detail
Analogy and Dynamic Geometry System Used to Introduce Three-Dimensional Geometry
Mammana, M. F.; Micale, B.; Pennisi, M.
2012-01-01
We present a sequence of classroom activities on Euclidean geometry, both plane and space geometry, used to make three dimensional geometry more catchy and simple. The activity consists of a guided research activity that leads the students to discover unexpected properties of two apparently distant geometrical entities, quadrilaterals and…
Gils, S; Hoveijn, I; Takens, F; Nonlinear Dynamical Systems and Chaos
1996-01-01
Symmetries in dynamical systems, "KAM theory and other perturbation theories", "Infinite dimensional systems", "Time series analysis" and "Numerical continuation and bifurcation analysis" were the main topics of the December 1995 Dynamical Systems Conference held in Groningen in honour of Johann Bernoulli. They now form the core of this work which seeks to present the state of the art in various branches of the theory of dynamical systems. A number of articles have a survey character whereas others deal with recent results in current research. It contains interesting material for all members of the dynamical systems community, ranging from geometric and analytic aspects from a mathematical point of view to applications in various sciences.
Rizo, P. J.; Pugzlys, A.; Slachter, A.; Denega, S. Z.; Reuter, D.; Wieck, A. D.; van Loosdrecht, P. H. M.; van der Wal, C. H.
2010-01-01
The electron spin dynamics in a GaAs/AlGaAs heterojunction system containing a high-mobility two-dimensional electron gas (2DEG) have been studied in this paper by using pump-probe time-resolved Kerr rotation experiments. Owing to the complex layer structure of this material, the transient Kerr
The Dynamics of Finite-Dimensional Systems Under Nonconservative Position Forces
Lobas, L. G.
2001-01-01
General theorems on the stability of stationary states of mechanical systems subjected to nonconservative position forces are presented. Specific mechanical problems on gyroscopic systems, a double-link pendulum with a follower force and elastically fixed upper tip, multilink pneumowheel vehicles, a monorail car, and rail-guided vehicles are analyzed. Methods for investigation of divergent bifurcations and catastrophes of stationary states are described
Detection and Prognostics on Low Dimensional Systems
National Aeronautics and Space Administration — This paper describes the application of known and novel prognostic algorithms on systems that can be described by low dimensional, potentially nonlinear dynamics....
Dynamics of coset dimensional reduction
Karthauser, Josef L. P.; Saffin, P. M.
2006-04-01
The evolution of multiple scalar fields in cosmology has been much studied, particularly when the potential is formed from a series of exponentials. For a certain subclass of such systems it is possible to get “assisted“ behavior, where the presence of multiple terms in the potential effectively makes it shallower than the individual terms indicate. It is also known that when compactifying on coset spaces one can achieve a consistent truncation to an effective theory which contains many exponential terms; however, if there are too many exponentials then exact scaling solutions do not exist. In this paper we study the potentials arising from such compactifications of eleven-dimensional supergravity and analyze the regions of parameter space which could lead to scaling behavior.
Exact Dimensional Reduction of Linear Dynamics: Application to Confined Diffusion
Kalinay, Pavol; Percus, Jerome K.
2006-06-01
In their stochastic versions, dynamical systems take the form of the linear dynamics of a probability distribution. We show that exact dimensional reduction of such systems can be carried out, and is physically relevant when the dimensions to be eliminated can be identified with those that represent transient behavior, disappearing under typical coarse graining. Application is made to non-uniform quasi-low dimensional diffusion, resulting in a systematic extension of the "classical" Fick-Jacobs approximate reduction to an exact subdynamics.
Energy Technology Data Exchange (ETDEWEB)
Griesbeck, Michael
2012-11-22
Since many years there has been great effort to explore the spin dynamics in low-dimensional electron systems embedded in GaAs/AlGaAs based heterostructures for the purpose of quantum computation and spintronics applications. Advances in technology allow for the design of high quality and well-defined two-dimensional electron systems (2DES), which are perfectly suited for the study of the underlying physics that govern the dynamics of the electron spin system. In this work, spin dynamics in high-mobility 2DES is studied by means of the all-optical time-resolved Kerr/Faraday rotation technique. In (001)-grown 2DES, a strong in-plane spin dephasing anisotropy is studied, resulting from the interference of comparable Rashba and Dresselhaus contributions to the spin-orbit field (SOF). The dependence of this anisotropy on parameters like the confinement length of the 2DES, the sample temperature, as well as the electron density is demonstrated. Furthermore, coherent spin dynamics of an ensemble of ballistically moving electrons is studied without and within an applied weak magnetic field perpendicular to the sample plane, which forces the electrons to move on cyclotron orbits. Finally, strongly anisotropic spin dynamics is investigated in symmetric (110)-grown 2DES, using the resonant spin amplification method. Here, extremely long out-of-plane spin dephasing times can be achieved, in consequence of the special symmetry of the Dresselhaus SOF.
Discretization model for nonlinear dynamic analysis of three dimensional structures
International Nuclear Information System (INIS)
Hayashi, Y.
1982-12-01
A discretization model for nonlinear dynamic analysis of three dimensional structures is presented. The discretization is achieved through a three dimensional spring-mass system and the dynamic response obtained by direct integration of the equations of motion using central diferences. First the viability of the model is verified through the analysis of homogeneous linear structures and then its performance in the analysis of structures subjected to impulsive or impact loads, taking into account both geometrical and physical nonlinearities is evaluated. (Author) [pt
Yonemitsu, Kenji
2005-01-01
Effectron-effectron interactions play an important role in nonequilibrium properties of molecular materials. First, we show differences between photoinduced ionic-to-neutral and neutral-to-ionic transitions in quasi-one-dimensional extended Peierls Hubbard models with alternating potentials. Cooperative dynamics lead to nonlinear ionicity in the former, while uncooperative dynamics lead to quite linear ionicity in the latter, as a function of the energy supplied from the oscillating effectric field. Interchain effectron-effectron interactions bring about initial competition among metastable and stable domains in neighboring chains, slowing down the phase transition. Interchain elastic couplings are necessary to form a ferroeffectric long-range order. Second, we show differences between field-effect characteristics of Mott insulators and those of band insulators in one-dimensional Hubbard models, to which tight-binding models are attached for metallic effectrodes and scalar potentials are added for interfacial barriers. Ambipolar characteristics are found in the former, while unipolar characteristics generally appear in the latter. In the former, charge transport is cooperative so that the drain current is insensitive to the difference between the work function of the channel and that of the effectrodes, and thus insensitive to the polarity of the gate bias.
Three dimensional system integration
Papanikolaou, Antonis; Radojcic, Riko
2010-01-01
Three-dimensional (3D) integrated circuit (IC) stacking is the next big step in electronic system integration. It enables packing more functionality, as well as integration of heterogeneous materials, devices, and signals, in the same space (volume). This results in consumer electronics (e.g., mobile, handheld devices) which can run more powerful applications, such as full-length movies and 3D games, with longer battery life. This technology is so promising that it is expected to be a mainstream technology a few years from now, less than 10-15 years from its original conception. To achieve thi
Birkhoff, George D
1927-01-01
His research in dynamics constitutes the middle period of Birkhoff's scientific career, that of maturity and greatest power. -Yearbook of the American Philosophical Society The author's great book€¦is well known to all, and the diverse active modern developments in mathematics which have been inspired by this volume bear the most eloquent testimony to its quality and influence. -Zentralblatt MATH In 1927, G. D. Birkhoff wrote a remarkable treatise on the theory of dynamical systems that would inspire many later mathematicians to do great work. To a large extent, Birkhoff was writing about his o
Introducing fluid dynamics using dimensional analysis
DEFF Research Database (Denmark)
Jensen, Jens Højgaard
2013-01-01
Many aspects of fluid dynamics can be introduced using dimensional analysis, combined with some basic physical principles. This approach is concise and allows exploration of both the laminar and turbulent limits—including important phenomena that are not normally dealt with when fluid dynamics...
Dynamic dimensionality reduction for hyperspectral imagery
Safavi, Haleh; Liu, Keng-Hao; Chang, Chein-I.
2011-06-01
Data dimensionality (DR) is generally performed by first fixing size of DR at a certain number, say p and then finding a technique to reduce an original data space to a low dimensional data space with dimensionality specified by p. This paper introduces a new concept of dynamic dimensionality reduction (DDR) which considers the parameter p as a variable by varying the value of p to make p adaptive compared to the commonly used DR, referred to as static dimensionality reduction (SDR) with the parameter p fixed at a constant value. In order to materialize the DDR another new concept, referred to as progressive DR (PDR) is also developed so that the DR can be performed progressively to adapt the variable size of data dimensionality determined by varying the value of p. The advantages of the DDR over SDR are demonstrated through experiments conducted for hyperspectral image classification.
Kang, An-Ming; Yan, Hong-Sen
2018-02-01
Though many studies are focused on the stabilization of nonlinear systems with time-varying delay, they fail to involve the dynamic regulation without on-line optimization commonly. For this sake, feedback linearization, Lyapunov-Razumikhin theorem and polynomial approximation theorem are employed here to verify that the multi-dimensional Taylor network (MTN) controller can stabilize the single input single output (SISO) nonlinear time-varying delay systems through dynamic regulation of the system output with no need for on-line optimization. Here, the design of the controller is transformed into a convex optimization problem, which is tackled by means of the appropriate optimization method. Like its PD-like controller peers, the MTN controller functions well in eliminating the dependence on the system model. The effectiveness of the proposed approach is demonstrated and confirmed via two examples. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Murakawa, Hideki; Hashimoto, Michinori; Sugimoto, Katsumi; Asano, Hitoshi; Takenaka, Nobuyuki; Mochiki, Koh-ichi; Yasuda, Ryo
2011-01-01
A dynamic CT system was developed for visualization of consecutive three-dimensional water behavior in a PEFC stack for neutron radiography. The system is composed of a neutron image intensifier and a C-MOS high speed video camera. An operating stack with three cells based on the Japan Automobile Research Institute standard was visualized using the neutron radiography system at a research reactor JRR-3 in Japan Atomic Energy Agency. The dynamic water behavior in channels in the operating PEFC stack was clearly visualized every 15 seconds by using the system. The water amount in each cell was evaluated by the CT reconstructed images. It was shown that a cell voltage decreased gradually when the water increased and increased rapidly when the water was evacuated. It was estimated that the power generation stopped when the channel of a cell was partly filled with the water because the air supply was blocked to a cell in the stack. (author)
Three dimensional reductions of four-dimensional quasilinear systems
Pavlov, Maxim V.; Stoilov, Nikola M.
2017-11-01
In this paper, we show that four-dimensional quasilinear systems of first order integrable by the method of two-dimensional hydrodynamic reductions possess infinitely many three-dimensional hydrodynamic reductions, which are also integrable systems. These three-dimensional multi-component integrable systems are irreducible to two-dimensional hydrodynamic reductions in a generic case.
International Nuclear Information System (INIS)
Schuetz, Gunter M
2003-01-01
Recent work on stochastic interacting particle systems with two particle species (or single-species systems with kinematic constraints) has demonstrated the existence of spontaneous symmetry breaking, long-range order and phase coexistence in nonequilibrium steady states, even if translational invariance is not broken by defects or open boundaries. If both particle species are conserved, the temporal behaviour is largely unexplored, but first results of current work on the transition from the microscopic to the macroscopic scale yield exact coupled nonlinear hydrodynamic equations and indicate the emergence of novel types of shock waves which are collective excitations stabilized by the flow of microscopic fluctuations. We review the basic stationary and dynamic properties of these systems, highlighting the role of conservation laws and kinetic constraints for the hydrodynamic behaviour, the microscopic origin of domain wall (shock) stability and the coarsening dynamics of domains during phase separation. (topical review)
Dynamic colloidal assembly pathways via low dimensional models
Energy Technology Data Exchange (ETDEWEB)
Yang, Yuguang; Bevan, Michael A., E-mail: mabevan@jhu.edu [Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Thyagarajan, Raghuram; Ford, David M. [Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
2016-05-28
Here we construct a low-dimensional Smoluchowski model for electric field mediated colloidal crystallization using Brownian dynamic simulations, which were previously matched to experiments. Diffusion mapping is used to infer dimensionality and confirm the use of two order parameters, one for degree of condensation and one for global crystallinity. Free energy and diffusivity landscapes are obtained as the coefficients of a low-dimensional Smoluchowski equation to capture the thermodynamics and kinetics of microstructure evolution. The resulting low-dimensional model quantitatively captures the dynamics of different assembly pathways between fluid, polycrystal, and single crystals states, in agreement with the full N-dimensional data as characterized by first passage time distributions. Numerical solution of the low-dimensional Smoluchowski equation reveals statistical properties of the dynamic evolution of states vs. applied field amplitude and system size. The low-dimensional Smoluchowski equation and associated landscapes calculated here can serve as models for predictive control of electric field mediated assembly of colloidal ensembles into two-dimensional crystalline objects.
Diaz-Ruelas, Alvaro; Jeldtoft Jensen, Henrik; Piovani, Duccio; Robledo, Alberto
2016-12-01
It is well known that low-dimensional nonlinear deterministic maps close to a tangent bifurcation exhibit intermittency and this circumstance has been exploited, e.g., by Procaccia and Schuster [Phys. Rev. A 28, 1210 (1983)], to develop a general theory of 1/f spectra. This suggests it is interesting to study the extent to which the behavior of a high-dimensional stochastic system can be described by such tangent maps. The Tangled Nature (TaNa) Model of evolutionary ecology is an ideal candidate for such a study, a significant model as it is capable of reproducing a broad range of the phenomenology of macroevolution and ecosystems. The TaNa model exhibits strong intermittency reminiscent of punctuated equilibrium and, like the fossil record of mass extinction, the intermittency in the model is found to be non-stationary, a feature typical of many complex systems. We derive a mean-field version for the evolution of the likelihood function controlling the reproduction of species and find a local map close to tangency. This mean-field map, by our own local approximation, is able to describe qualitatively only one episode of the intermittent dynamics of the full TaNa model. To complement this result, we construct a complete nonlinear dynamical system model consisting of successive tangent bifurcations that generates time evolution patterns resembling those of the full TaNa model in macroscopic scales. The switch from one tangent bifurcation to the next in the sequences produced in this model is stochastic in nature, based on criteria obtained from the local mean-field approximation, and capable of imitating the changing set of types of species and total population in the TaNa model. The model combines full deterministic dynamics with instantaneous parameter random jumps at stochastically drawn times. In spite of the limitations of our approach, which entails a drastic collapse of degrees of freedom, the description of a high-dimensional model system in terms of a low-dimensional
Pyragas, K.; Lange, F.; Letz, T.; Parisi, J.; Kittel, A.
2001-01-01
We suggest a quantitatively correct procedure for reducing the spatial degrees of freedom of the space-dependent rate equations of a multimode laser that describe the dynamics of the population inversion of the active medium and the mode intensities of the standing waves in the laser cavity. The key idea of that reduction is to take advantage of the small value of the parameter that defines the ratio between the population inversion decay rate and the cavity decay rate. We generalize the reduction procedure for the case of an intracavity frequency doubled laser. Frequency conversion performed by an optically nonlinear crystal placed inside the laser cavity may cause a pronounced instability in the laser performance, leading to chaotic oscillations of the output intensity. Based on the reduced equations, we analyze the dynamical properties of the system as well as the problem of stabilizing the steady state. The numerical analysis is performed considering the specific system of a Nd:YAG (neodymium-doped yttrium aluminum garnet) laser with an intracavity KTP (potassium titanyl phosphate) crystal.
Charge Dynamics in Low Dimensional Prototype Correlated Systems: A View with High-Energy X-rays
Energy Technology Data Exchange (ETDEWEB)
Hasan, Md-Zahid
2002-03-20
The electronic structure of Mott systems continues to be an unsolved problem in physics despite more than half-century of intense research efforts. Well-developed momentum-resolved spectroscopies such as photoemission and neutron scattering cannot directly address problems associated with the full Mott gap as angle-resolved photoemission probes the occupied states and neutrons do not couple to the electron's charge directly. Our observation of dispersive particle- hole pair excitations across the charge gap (effective Mott gap) in several low dimensional prototype Mott insulators using high resolution resonant inelastic x-ray scattering suggests that the excitations across the gap are highly anisotropic and momentum dependent. The results indirectly provide some information about the momentum dependence of unoccupied states in these correlated systems. The x-ray scattering results are complementary to the electron scattering results by the possibility of studying the excitations in the high momentum transfer regimes (near the zone boundaries and comers). This is also demonstrated in case of studying plasmons near the wave vector regime where Landau damping starts to dominate. X-ray scattering also allows one to probe the symmetry characters of localized electrons and the excitations through the strong polarization dependence of scattering near a core resonance. The study of charge-orbital localization is demonstrated in case of manganese oxides. Given its deeply bulk-sensitive and weak-coupling nature and the ability to probe dispersive behavior of charge fluctuations over several Brillouin zones, inelastic x-ray scattering shows the promise to become an important experimental tool to study the electronic structure of complex quantum systems.
Dimensional reduction, monopoles and dynamical symmetry breaking
Dolan, Brian P.; Szabo, Richard J.
2009-03-01
We consider SU(2)-equivariant dimensional reduction of Yang-Mills-Dirac theory on manifolds of the form M × Bbb CP1, with emphasis on the effects of non-trivial magnetic flux on Bbb CP1. The reduction of Yang-Mills fields gives a chain of coupled Yang-Mills-Higgs systems on M with a Higgs potential leading to dynamical symmetry breaking, as a consequence of the monopole fields. The reduction of SU(2)-symmetric fermions gives massless Dirac fermions on M transforming under the low-energy gauge group with Yukawa couplings, again as a result of the internal U(1) fluxes. The tower of massive fermionic Kaluza-Klein states also has Yukawa interactions and admits a natural SU(2)-equivariant truncation by replacing Bbb CP1 with a fuzzy sphere. In this approach it is possible to obtain exactly massless chiral fermions in the effective field theory with Yukawa interactions, without any further requirements. We work out the spontaneous symmetry breaking patterns and determine the complete physical particle spectrum in a number of explicit examples.
Wang, Yuwen
2016-09-22
We study the dynamics of an ultrafast single photon pulse in a one-dimensional waveguide two-point coupled with a Jaynes-Cummings system. We find that for any single photon input the transmissivity depends periodically on the separation between the two coupling points. For a pulse containing many plane wave components it is almost impossible to suppress transmission, especially when the width of the pulse is less than 20 times the period. In contrast to plane wave input, the waveform of the pulse can be modified by controlling the coupling between the waveguide and Jaynes-Cummings system. Tailoring of the waveform is important for single photon manipulation in quantum informatics. © The Author(s) 2016.
Analyzing Protein Dynamics Using Dimensionality Reduction
Eryol, Atahan
2015-01-01
This thesis investigates dimensionality reduction for analyzing the dynamics ofprotein simulations, particularly disordered proteins which do not fold into a xedshape but are thought to perform their functions through their movements. Ratherthan analyze the movement of the proteins in 3D space, we use dimensionalityreduction to project the molecular structure of the proteins into a target space inwhich each structure is represented as a point. All that is needed to do this arethe pairwise dis...
Complexity in Dynamical Systems
Moore, Cristopher David
The study of chaos has shown us that deterministic systems can have a kind of unpredictability, based on a limited knowledge of their initial conditions; after a finite time, the motion appears essentially random. This observation has inspired a general interest in the subject of unpredictability, and more generally, complexity; how can we characterize how "complex" a dynamical system is?. In this thesis, we attempt to answer this question with a paradigm of complexity that comes from computer science, we extract sets of symbol sequences, or languages, from a dynamical system using standard methods of symbolic dynamics; we then ask what kinds of grammars or automata are needed a generate these languages. This places them in the Chomsky heirarchy, which in turn tells us something about how subtle and complex the dynamical system's behavior is. This gives us insight into the question of unpredictability, since these automata can also be thought of as computers attempting to predict the system. In the culmination of the thesis, we find a class of smooth, two-dimensional maps which are equivalent to the highest class in the Chomsky heirarchy, the turning machine; they are capable of universal computation. Therefore, these systems possess a kind of unpredictability qualitatively different from the usual "chaos": even if the initial conditions are known exactly, questions about the system's long-term dynamics are undecidable. No algorithm exists to answer them. Although this kind of unpredictability has been discussed in the context of distributed, many-degree-of -freedom systems (for instance, cellular automata) we believe this is the first example of such phenomena in a smooth, finite-degree-of-freedom system.
Energy Technology Data Exchange (ETDEWEB)
Vath, Andreas
2008-12-15
This thesis deals with dynamic and multi-dimensional modelling of Polymer- Electrolyte-Membrane-Fuel-Cells (PEMFC). The developed models include all the different layers of the fuel cell e.g. flow field, gas diffusion layer, catalyst layer and membrane with their particular physical, chemical and electrical characteristics. The simulation results have been verified by detailed measurements performed at the research centre for hydrogen and solar energy in Ulm (ZSW Ulm). The developed three dimensional model describes the time- and spatial-dependent charge and mass transport in a fuel cell. Additionally, this model allows the analysis of critical operating conditions. For example, the current density distribution for different membranes is shown during insufficient humidification which results in local overstraining and degradation. The model also allows to analyse extreme critical operating conditions, e.g. short time breakdown of the humidification. Furthermore, the model shows the available potential of improvement opportunities in power density and efficiency of PEMFC due to optimisation of the gas diffusion layer, the catalyst and membrane. In the second part of the work the application of PEMFC systems for combined heat and power units is described by one-dimensional models for an electrical power range between 1 kW and 5 kW. This model contains the necessary components, e.g. gas processing, humidification, gas supply, fuel cell stack, heat storage, pumps, auxiliary burner, power inverter und additional aggregates. As a main result, it is possible to distinctly reduce the energy demand and the carbon dioxide exhaust for different load profiles. Today the costs for fuel cell systems are considerably higher than that of the conventional electrical energy supply. (orig.)
Low-dimensional manifold of actin polymerization dynamics
Floyd, Carlos; Jarzynski, Christopher; Papoian, Garegin
2017-12-01
Actin filaments are critical components of the eukaryotic cytoskeleton, playing important roles in a number of cellular functions, such as cell migration, organelle transport, and mechanosensation. They are helical polymers with a well-defined polarity, composed of globular subunits that bind nucleotides in one of three hydrolysis states (ATP, ADP-Pi, or ADP). Mean-field models of the dynamics of actin polymerization have succeeded in, among other things, determining the nucleotide profile of an average filament and resolving the mechanisms of accessory proteins. However, these models require numerical solution of a high-dimensional system of nonlinear ordinary differential equations. By truncating a set of recursion equations, the Brooks-Carlsson (BC) model reduces dimensionality to 11, but it still remains nonlinear and does not admit an analytical solution, hence, significantly hindering understanding of its resulting dynamics. In this work, by taking advantage of the fast timescales of the hydrolysis states of the filament tips, we propose two model reduction schemes: the quasi steady-state approximation model is five-dimensional and nonlinear, whereas the constant tip (CT) model is five-dimensional and linear, resulting from the approximation that the tip states are not dynamic variables. We provide an exact solution of the CT model and use it to shed light on the dynamical behaviors of the full BC model, highlighting the relative ordering of the timescales of various collective processes, and explaining some unusual dependence of the steady-state behavior on initial conditions.
4+ Dimensional nuclear systems engineering
International Nuclear Information System (INIS)
Suh, Kune Y.
2009-01-01
Nuclear power plants (NPPs) require massive quantity of data during the design, construction, operation, maintenance and decommissioning stages because of their special features like size, cost, radioactivity, and so forth. The system engineering thus calls for a fully integrated way of managing the information flow spanning their life cycle. This paper proposes digital systems engineering anchored in three dimensional (3D) computer aided design (CAD) models. The signature in the proposal lies with the four plus dimensional (4 + D) Technology TM , a critical know how for digital management. ESSE (Engineering Super Simulation Emulation) features a 4 + D Technology TM for nuclear energy systems engineering. The technology proposed in the 3D space and time plus cost coordinates, i.e. 4 + D, is the backbone of digital engineering in the nuclear systems design and management. Dased on an integrated 3D configuration management system, ESSE consists of solutions JANUS (Junctional Analysis Neodynamic Unit SoftPower), EURUS (Engineering Utilities Research Unit SoftPower), NOTUS (Neosystemic Optimization Technical Unit SoftPower), VENUS (Virtual Engineering Neocybernetic Unit SoftPower) and INUUS (Informative Neographic Utilities Unit SoftPower). NOTUS contributes to reducing the construction cost of the NPPs by optimizing the component manufacturing procedure and the plant construction process. Planning and scheduling construction projects can thus benefit greatly by integrating traditional management techniques with digital process simulation visualization. The 3D visualization of construction processes and the resulting products intrinsically afford most of the advantages realized by incorporating a purely schedule level detail based the 4 + D system. Problems with equipment positioning and manpower congestion in certain areas can be visualized prior to the actual operation, thus preventing accidents and safety problems such as collision between two machines and losses in
Dynamics of two-dimensional bubbles
Piedra, Saúl; Ramos, Eduardo; Herrera, J. Ramón
2015-06-01
The dynamics of two-dimensional bubbles ascending under the influence of buoyant forces is numerically studied with a one-fluid model coupled with the front-tracking technique. The bubble dynamics are described by recording the position, shape, and orientation of the bubbles as functions of time. The qualitative properties of the bubbles and their terminal velocities are described in terms of the Eötvos (ratio of buoyancy to surface tension) and Archimedes numbers (ratio of buoyancy to viscous forces). The terminal Reynolds number result from the balance of buoyancy and drag forces and, consequently, is not an externally fixed parameter. In the cases that yield small Reynolds numbers, the bubbles follow straight paths and the wake is steady. A more interesting behavior is found at high Reynolds numbers where the bubbles follow an approximately periodic zigzag trajectory and an unstable wake with properties similar to the Von Karman vortex street is formed. The dynamical features of the motion of single bubbles are compared to experimental observations of air bubbles ascending in a water-filled Hele-Shaw cell. Although the comparison is not strictly valid in the sense that the effect of the lateral walls is not incorporated in the model, most of the dynamical properties observed are in good qualitative agreement with the numerical calculations. Hele-Shaw cells with different gaps have been used to determine the degree of approximation of the numerical calculation. It is found that for the relation between the terminal Reynolds number and the Archimedes number, the numerical calculations are closer to the observations of bubble dynamics in Hele-Shaw cells of larger gaps.
Dynamical heterogeneities and defects in two-dimensional soft colloidal crystals
Meer, Van Der B.; Qi, W.; Sprakel, J.; Filion, L.; Dijkstra, M.
2015-01-01
In this paper we study a two-dimensional system of charged colloidal particles using Brownian dynamics simulations. We determine the phase diagram and investigate the dynamics of this system in the density regime where hexatic and solid phases are stable. We find that the dynamics in these phases
Quantum quench dynamics in analytically solvable one-dimensional models
Iucci, Anibal; Cazalilla, Miguel A.; Giamarchi, Thierry
2008-03-01
In connection with experiments in cold atomic systems, we consider the non-equilibrium dynamics of some analytically solvable one-dimensional systems which undergo a quantum quench. In this quench one or several of the parameters of the Hamiltonian of an interacting quantum system are changed over a very short time scale. In particular, we concentrate on the Luttinger model and the sine-Gordon model in the Luther-Emery point. For the latter, we show that the order parameter and the two-point correlation function relax in the long time limit to the values determined by a generalized Gibbs ensemble first discussed by J. T. Jaynes [Phys. Rev. 106, 620 (1957); 108, 171 (1957)], and recently conjectured by M. Rigol et.al. [Phys. Rev. Lett. 98, 050405 (2007)] to apply to the non-equilibrium dynamics of integrable systems.
Multimodal three-dimensional dynamic signature
Directory of Open Access Journals (Sweden)
Yury E. Kozlov
2017-11-01
Full Text Available Reliable authentication in mobile applications is among the most important information security challenges. Today, we can hardly imagine a person who would not own a mobile device that connects to the Internet. Mobile devices are being used to store large amounts of confidential information, ranging from personal photos to electronic banking tools. In 2009, colleagues from Rice University together with their collaborators from Motorola, proposed an authentication through in-air gestures. This and subsequent work contributing to the development of the method are reviewed in our introduction. At the moment, there exists a version of the gesture-based authentication software available for Android mobile devices. This software has not become widespread yet. One of likely reasons for that is the insufficient reliability of the method, which involves similar to its earlier analogs the use of only one device. Here we discuss the authentication based on the multimodal three-dimensional dynamic signature (MTDS performed by two independent mobile devices. The MTDS-based authentication technique is an advanced version of in-air gesture authentication. We describe the operation of a prototype of MTDS-based authentication, including the main implemented algorithms, as well as some preliminary results of testing the software. We expect that our method can be used in any mobile application, provided a number of additional improvements discussed in the conclusion are made.
Integrable finite-dimensional systems related to Lie algebras
International Nuclear Information System (INIS)
Olshanetsky, M.A.; Perelomov, A.M.
1979-01-01
Some solvable finite-dimensional classical and quantum systems related to the Lie algebras are considered. The dynamics of these systems is closely related to free motion on symmetric spaces. In specific cases the systems considered describe the one-dimensional n-body problem recently considered by many authors. The review represents from general and universal point of view the results obtained during the last few years. Besides, it contains some results both of physical and mathematical type
Three-dimensional dynamic range reduction techniques
Harding, Kevin G.; Qian, Xiaoping
2004-02-01
A significant limitation of the application of 3D structured light systems has been the large dynamic range of reflectivity of typical parts such as machined parts. The advent of digital cameras have helped this problem to some extent by providing a larger dynamic range of detection, but often parts must still be coated with white paint or powder to get a good enough return for 3D measurement techniques such as structured light. This paper will present an overview of methods that have been used to minimize the range of light reflections from many parts including polarization, multiple exposure, multiple viewing and masking techniques. Also presented will be methods of analysis such as phase analysis techniques which can provide improved robustness. Finally, we will discuss the pros and cons of these options as applied to the application of 3D structured light techniques to machined metal parts.
High dimensional model representation method for fuzzy structural dynamics
Adhikari, S.; Chowdhury, R.; Friswell, M. I.
2011-03-01
Uncertainty propagation in multi-parameter complex structures possess significant computational challenges. This paper investigates the possibility of using the High Dimensional Model Representation (HDMR) approach when uncertain system parameters are modeled using fuzzy variables. In particular, the application of HDMR is proposed for fuzzy finite element analysis of linear dynamical systems. The HDMR expansion is an efficient formulation for high-dimensional mapping in complex systems if the higher order variable correlations are weak, thereby permitting the input-output relationship behavior to be captured by the terms of low-order. The computational effort to determine the expansion functions using the α-cut method scales polynomically with the number of variables rather than exponentially. This logic is based on the fundamental assumption underlying the HDMR representation that only low-order correlations among the input variables are likely to have significant impacts upon the outputs for most high-dimensional complex systems. The proposed method is first illustrated for multi-parameter nonlinear mathematical test functions with fuzzy variables. The method is then integrated with a commercial finite element software (ADINA). Modal analysis of a simplified aircraft wing with fuzzy parameters has been used to illustrate the generality of the proposed approach. In the numerical examples, triangular membership functions have been used and the results have been validated against direct Monte Carlo simulations. It is shown that using the proposed HDMR approach, the number of finite element function calls can be reduced without significantly compromising the accuracy.
Czech Academy of Sciences Publication Activity Database
Pánek, D.; Hrušák, J.; Doležel, Ivo
2007-01-01
Roč. 43, č. 596 (2007), s. 46-51 ISSN 0321-0499 R&D Projects: GA ČR(CZ) GA102/07/0496 Institutional research plan: CEZ:AV0Z20570509 Keywords : chaotic behavior * low-dimensional chaotic systems * Rikitake dynamo Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
DEFF Research Database (Denmark)
Thomsen, Per Grove
1996-01-01
A one-dimensional model with axial discretization of engine components has been formulated using tha balance equations for mass energy and momentum and the ideal gas equation of state. ODE's that govern the dynamic behaviour of the regenerator matrix temperatures are included in the model. Known...
McDonough, J M
2009-06-01
Outline of the derivation and mathematical and physical interpretations are presented for a discrete dynamical system known as the "poor man's Navier-Stokes equation." Numerical studies demonstrate that velocity fields produced by this dynamical system are similar to those seen in laboratory experiments and in detailed simulations, and they lead to scaling for the turbulence kinetic energy spectrum in accord with Kolmogorov K41 theory.
Dynamic Interactive Learning Systems
Sabry, Khaled; Barker, Jeff
2009-01-01
This paper reviews and discusses the notions of interactivity and dynamicity of learning systems in relation to information technologies and design principles that can contribute to interactive and dynamic learning. It explores the concept of dynamic interactive learning systems based on the emerging generation of information as part of a…
Indian Academy of Sciences (India)
dimensional functions of the (2+1)-dimensional Broer–Kaup (BK) equations was derived by means of a projec- tive equation method and a variable separation hypothesis. Based on the derived variable separation excitation, some new special ...
Pilyugin, Sergei Yu
2012-01-01
Dynamical systems are abundant in theoretical physics and engineering. Their understanding, with sufficient mathematical rigor, is vital to solving many problems. This work conveys the modern theory of dynamical systems in a didactically developed fashion.In addition to topological dynamics, structural stability and chaotic dynamics, also generic properties and pseudotrajectories are covered, as well as nonlinearity. The author is an experienced book writer and his work is based on years of teaching.
Aspects of dynamical dimensional reduction in multigraph ensembles of CDT
Giasemidis, Georgios; Wheater, John F.; Zohren, Stefan
2013-02-01
We study the continuum limit of a "radially reduced" approximation of Causal Dynamical Triangulations (CDT), so-called multigraph ensembles, and explain why they serve as realistic toy models to study the dimensional reduction observed in numerical simulations of four-dimensional CDT. We present properties of this approximation in two, three and four dimensions comparing them with the numerical simulations and pointing out some common features with 2+1 dimensional Hořava-Lifshitz gravity.
Multi-dimensional passive sampled Port-Hamiltonian systems
Franken, M.C.J.; Reilink, Rob; Misra, Sarthak; Stramigioli, Stefano
2010-01-01
Passivity of virtual environments running in discrete time is a sufficient condition for stability of the system. The framework for passive sampled Port-Hamiltonian systems allows multi-dimensional virtual environments exhibiting internal dynamic behavior to be computed on a discrete medium in a
Port Hamiltonian Formulation of Infinite Dimensional Systems I. Modeling
Macchelli, Alessandro; Schaft, Arjan J. van der; Melchiorri, Claudio
2004-01-01
In this paper, some new results concerning the modeling of distributed parameter systems in port Hamiltonian form are presented. The classical finite dimensional port Hamiltonian formulation of a dynamical system is generalized in order to cope with the distributed parameter and multi-variable case.
Port Hamiltonian formulation of infinite dimensional systems I. Modeling
Macchelli, Alessandro; Macchelli, A.; van der Schaft, Arjan; Melchiorri, Claudio
2004-01-01
In this paper, some new results concerning the modeling of distributed parameter systems in port Hamiltonian form are presented. The classical finite dimensional port Hamiltonian formulation of a dynamical system is generalized in order to cope with the distributed parameter and multivariable case.
Distributed port-Hamiltonian formulation of infinite dimensional systems
Macchelli, Alessandro; Macchelli, A.; van der Schaft, Arjan; Melchiorri, Claudio
2004-01-01
In this paper, some new results concerning the modeling and control of distributed parameter systems in port Hamiltonian form are presented. The classical finite dimensional port Hamiltonian formulation of a dynamical system is generalized in order to cope with the distributed parameter and
Dynamic masquerade with morphing three-dimensional skin in cuttlefish.
Panetta, Deanna; Buresch, Kendra; Hanlon, Roger T
2017-03-01
Masquerade is a defence tactic in which a prey resembles an inedible or inanimate object thus causing predators to misclassify it. Most masquerade colour patterns are static although some species adopt postures or behaviours to enhance the effect. Dynamic masquerade in which the colour pattern can be changed is rare. Here we report a two-step sensory process that enables an additional novel capability known only in cuttlefish and octopus: morphing three-dimensional physical skin texture that further enhances the optical illusions created by coloured skin patterns. Our experimental design incorporated sequential sensory processes: addition of a three-dimensional rock to the testing arena, which attracted the cuttlefish to settle next to it; then visual processing by the cuttlefish of physical textures on the rock to guide expression of the skin papillae, which can range from fully relaxed (smooth skin) to fully expressed (bumpy skin). When a uniformly white smooth rock was presented, cuttlefish moved to the rock and deployed a uniform body pattern with mostly smooth skin. When a rock with small-scale fragments of contrasting shells was presented, the cuttlefish deployed mottled body patterns with strong papillae expression. These robust and reversible responses indicate a sophisticated visual sensorimotor system for dynamic masquerade. © 2017 The Author(s).
DEFF Research Database (Denmark)
Thomsen, Per Grove
1996-01-01
A one-dimensional model with axial discretization of engine components has been formulated using tha balance equations for mass energy and momentum and the ideal gas equation of state. ODE's that govern the dynamic behaviour of the regenerator matrix temperatures are included in the model. Known ...... loss mechanisms are coupled directly into the governing equations instead of applying losses as corrections to simulation results from an idealised model....
Naeimi, Meysam; Zakeri, Jabbar Ali; Esmaeili, Morteza; Shadfar, Morad
2015-01-01
A mathematical model of the vehicle-track interaction is developed to investigate the coupled behaviour of vehicle-track system, in the presence of uneven irregularities at left/right rails. The railway vehicle is simplified as a 3D multi-rigid-body model, and the track is treated as the two parallel beams on a layered discrete support system. Besides the car-body, the bogies and the wheel sets, the sleepers are assumed to have roll degree of freedom, in order to simulate the in-plane rotation of the components. The wheel-rail interface is treated using a nonlinear Hertzian contact model, coupling the mathematical equations of the vehicle-track systems. The dynamic interaction of the entire system is numerically studied in time domain, employing Newmark's integration method. The track irregularity spectra of both the left/right rails are taken into account, as the inputs of dynamic excitations. The dynamic responses of the track system induced by such irregularities are obtained, particularly in terms of the vertical (bounce) and roll displacements. The numerical model of the present research is validated using several benchmark models reported in the literature, for both the smooth and unsmooth track conditions. Four sample profiles of the measured rail irregularities are considered as the case studies of excitation sources, examining their influences on the dynamic behaviour of the coupled system. The results of numerical simulations demonstrate that the motion of track system is significantly influenced by the presence of uneven irregularities in left/right rails. Dynamic response of the sleepers in the roll direction becomes more sensitive to the rail irregularities, as the unevenness severity of the parallel profiles (quantitative difference between left and right rail spectra) is increased. The severe geometric deformation of the track in the bounce-pitch-roll directions is mainly related to such profile unevenness (cross-level) in left/right rails.
Systems With Emergent Dynamics
Stewart, Ian
2002-09-01
Evolutionary biologists often reject deterministic models of evolutionary processes because they equate `deterministic' with `goal-seeking', and have learned the hard way not to trust goal-seeking explanations of evolutionary adaptations. On the other hand, the general theory of dynamical systems potentially has much to offer for evolutionary biology— for example, as a resolution of the conflict between gradualism and punctuated equilibrium. The concept of a system with emergent dynamics retains the deterministic nature of dynamical systems, while eliminating any goal-seeking interpretation. Define an emergent property of a complex system to be a property whose computation from the entity-level rules of the system is intractable (in some reasonable sense). Say that a dynamical system has emergent dynamics if the computation of trajectories is intractable. Then systems with emergent dynamics are deterministic but not goal-seeking. As such, they offer a sensible way to use dynamical systems as models for evolutionary processes in biology, and in other areas. We discuss these issues and examine a few simple aspects of emergence in dynamical systems.
Indian Academy of Sciences (India)
straints [17], as a concrete example to study possible oscillating soliton structures in higher-dimensional physical models. The (2+1)-dimensional BK equations have been extensively studied in several papers [18–22]. Abundant solutions, such as soliton-like solutions, triangular-like solutions, single and combined ...
Dynamic Systems and Control Engineering
International Nuclear Information System (INIS)
Kim, Jong Seok
1994-02-01
This book deals with introduction of dynamic system and control engineering, frequency domain modeling of dynamic system, temporal modeling of dynamic system, typical dynamic system and automatic control device, performance and stability of control system, root locus analysis, analysis of frequency domain dynamic system, design of frequency domain dynamic system, design and analysis of space, space of control system and digital control system such as control system design of direct digital and digitalization of consecutive control system.
Molecular dynamics study of two- and three-dimensional classical ...
Indian Academy of Sciences (India)
Abstract. We have carried out a molecular dynamics simulation of two- and three- dimensional double Yukawa fluids near the triple point. We have compared some of the static and dynamic correlation functions with those of Lennard–Jones, when parameters occurring in double Yukawa potential are chosen to fit ...
Inference in High-dimensional Dynamic Panel Data Models
DEFF Research Database (Denmark)
Kock, Anders Bredahl; Tang, Haihan
We establish oracle inequalities for a version of the Lasso in high-dimensional fixed effects dynamic panel data models. The inequalities are valid for the coefficients of the dynamic and exogenous regressors. Separate oracle inequalities are derived for the fixed effects. Next, we show how one can...
Dynamics of higher-dimensional FRW cosmology in Rp exp (λR ...
Indian Academy of Sciences (India)
We study the cosmological dynamics for R p exp( λ R ) gravity theory in the metric formalism, using dynamical systems approach. Considering higher-dimensional FRW geometries in case of an imperfect fluid which has two different scale factors in the normal and extra dimensions, we find the exact solutions, and study its ...
Stability of dynamical systems
Liao, Xiaoxin; Yu, P 0
2007-01-01
The main purpose of developing stability theory is to examine dynamic responses of a system to disturbances as the time approaches infinity. It has been and still is the object of intense investigations due to its intrinsic interest and its relevance to all practical systems in engineering, finance, natural science and social science. This monograph provides some state-of-the-art expositions of major advances in fundamental stability theories and methods for dynamic systems of ODE and DDE types and in limit cycle, normal form and Hopf bifurcation control of nonlinear dynamic systems.ʺ Presents
Attractors and basins of dynamical systems
Directory of Open Access Journals (Sweden)
Attila Dénes
2011-03-01
Full Text Available There are several programs for studying dynamical systems, but none of them is very useful for investigating basins and attractors of higher dimensional systems. Our goal in this paper is to show a new algorithm for finding even chaotic attractors and their basins for these systems. We present an implementation and examples for the use of this program.
Three-Dimensional Dynamic Loading of Sand
2011-02-01
oading conditions exist at the bulk scale, and exam ples include planetary impact and crater formation, tectonic plate movement , ballistic im pact and...found further way from an impact event, where the bulk material does not necessarily experience uniform loading in excess of the Hugoniot elastic li...either as a collection of quartz spheres in a three-dimensional rectilinear dom ain for t he mesoscale simulations or as a single representative material
International Nuclear Information System (INIS)
Posch, H.A.; Narnhofer, H.; Thirring, W.
1990-01-01
We study the dynamics of classical particles interacting with attractive Gaussian potentials. This system is thermodynamically not stable and exhibits negative specific heat. The results of the computer simulation of the dynamics are discussed in comparison with various theories. In particular, we find that the condensed phase is a stationary solution of the Vlasov equation, but the Vlasov dynamics cannot describe the collapse. 14 refs., 1 tab., 11 figs. (Authors)
Analysis of chaos in high-dimensional wind power system.
Wang, Cong; Zhang, Hongli; Fan, Wenhui; Ma, Ping
2018-01-01
A comprehensive analysis on the chaos of a high-dimensional wind power system is performed in this study. A high-dimensional wind power system is more complex than most power systems. An 11-dimensional wind power system proposed by Huang, which has not been analyzed in previous studies, is investigated. When the systems are affected by external disturbances including single parameter and periodic disturbance, or its parameters changed, chaotic dynamics of the wind power system is analyzed and chaotic parameters ranges are obtained. Chaos existence is confirmed by calculation and analysis of all state variables' Lyapunov exponents and the state variable sequence diagram. Theoretical analysis and numerical simulations show that the wind power system chaos will occur when parameter variations and external disturbances change to a certain degree.
Analysis of chaos in high-dimensional wind power system
Wang, Cong; Zhang, Hongli; Fan, Wenhui; Ma, Ping
2018-01-01
A comprehensive analysis on the chaos of a high-dimensional wind power system is performed in this study. A high-dimensional wind power system is more complex than most power systems. An 11-dimensional wind power system proposed by Huang, which has not been analyzed in previous studies, is investigated. When the systems are affected by external disturbances including single parameter and periodic disturbance, or its parameters changed, chaotic dynamics of the wind power system is analyzed and chaotic parameters ranges are obtained. Chaos existence is confirmed by calculation and analysis of all state variables' Lyapunov exponents and the state variable sequence diagram. Theoretical analysis and numerical simulations show that the wind power system chaos will occur when parameter variations and external disturbances change to a certain degree.
Shadowing in dynamical systems
Pilyugin, Sergei Yu
1999-01-01
This book is an introduction to the theory of shadowing of approximate trajectories in dynamical systems by exact ones. This is the first book completely devoted to the theory of shadowing. It shows the importance of shadowing theory for both the qualitative theory of dynamical systems and the theory of numerical methods. Shadowing Methods allow us to estimate differences between exact and approximate solutions on infinite time intervals and to understand the influence of error terms. The book is intended for specialists in dynamical systems, for researchers and graduate students in the theory of numerical methods.
Three-dimensional reactor dynamics code for VVER type nuclear reactors
Energy Technology Data Exchange (ETDEWEB)
Kyrki-Rajamaeki, R. [VTT Energy, Espoo (Finland)
1995-10-01
A three-dimensional reactor dynamics computer code has been developed, validated and applied for transient and accident analyses of VVER type nuclear reactors. This code, HEXTRAN, is a part of the reactor physics and dynamics calculation system of the Technical Research Centre of Finland, VTT. HEXTRAN models accurately the VVER core with hexagonal fuel assemblies. The code uses advanced mathematical methods in spatial and time discretization of neutronics, heat transfer and the two-phase flow equations of hydraulics. It includes all the experience of VTT from 20 years on the accurate three-dimensional static reactor physics as well as on the one-dimensional reactor dynamics. The dynamic coupling with the thermal hydraulic system code SMABRE also allows the VVER circuit-modelling experience to be included in the analyses. (79 refs.).
Three-dimensional reactor dynamics code for VVER type nuclear reactors
International Nuclear Information System (INIS)
Kyrki-Rajamaeki, R.
1995-10-01
A three-dimensional reactor dynamics computer code has been developed, validated and applied for transient and accident analyses of VVER type nuclear reactors. This code, HEXTRAN, is a part of the reactor physics and dynamics calculation system of the Technical Research Centre of Finland, VTT. HEXTRAN models accurately the VVER core with hexagonal fuel assemblies. The code uses advanced mathematical methods in spatial and time discretization of neutronics, heat transfer and the two-phase flow equations of hydraulics. It includes all the experience of VTT from 20 years on the accurate three-dimensional static reactor physics as well as on the one-dimensional reactor dynamics. The dynamic coupling with the thermal hydraulic system code SMABRE also allows the VVER circuit-modelling experience to be included in the analyses. (79 refs.)
Three-dimensional dynamics of supported pipes conveying fluid
Wang, L.; Jiang, T. L.; Dai, H. L.
2017-12-01
This paper deals with the three-dimensional dynamics and postbuckling behavior of flexible supported pipes conveying fluid, considering flow velocities lower and higher than the critical value at which the buckling instability occurs. In the case of low flow velocity, the pipe is stable with a straight equilibrium position and the dynamics of the system can be examined using linear theory. When the flow velocity is beyond the critical value, any motions of the pipe could be around the postbuckling configuration (non-zero equilibrium position) rather than the straight equilibrium position, so nonlinear theory is required. The nonlinear equations of perturbed motions around the postbuckling configuration are derived and solved with the aid of Galerkin discretization. It is found, for a given flow velocity, that the first-mode frequency for in-plane motions is quite different from that for out-of-plane motions. However, the second- or third-mode frequencies for in-plane motions are approximately equal to their counterparts for out-of-plane motions, keeping almost constant values with increasing flow velocity. Moreover, the orientation angle of the postbuckling configuration plane for a buckled pipe can be significantly affected by initial conditions, displaying new features which have not been observed in the same pipe system factitiously supposed to deform in a single plane.
Irving, Daniel; Sorrentino, Francesco
2012-11-01
We present a general framework to study stability of the synchronous solution for a hypernetwork of coupled dynamical systems. We are able to reduce the dimensionality of the problem by using simultaneous block diagonalization of matrices. We obtain necessary and sufficient conditions for stability of the synchronous solution in terms of a set of lower-dimensional problems and test the predictions of our low-dimensional analysis through numerical simulations. Under certain conditions, this technique may yield a substantial reduction of the dimensionality of the problem. For example, for a class of dynamical hypernetworks analyzed in the paper, we discover that arbitrarily large networks can be reduced to a collection of subsystems of dimensionality no more than 2. We apply our reduction technique to a number of different examples, including the class of undirected unweighted hypermotifs with 3 nodes.
Invitation to dynamical systems
Scheinerman, Edward R
2012-01-01
This text is designed for those who wish to study mathematics beyond linear algebra but are unready for abstract material. Rather than a theorem-proof-corollary exposition, it stresses geometry, intuition, and dynamical systems. 1996 edition.
Three dimensional dynamics of a flexible Motorised Momentum Exchange Tether
Ismail, N. A.; Cartmell, M. P.
2016-03-01
This paper presents a new flexural model for the three dimensional dynamics of the Motorised Momentum Exchange Tether (MMET) concept. This study has uncovered the relationships between planar and nonplanar motions, and the effect of the coupling between these two parameters on pragmatic circular and elliptical orbits. The tether sub-spans are modelled as stiffened strings governed by partial differential equations of motion, with specific boundary conditions. The tether sub-spans are flexible and elastic, thereby allowing three dimensional displacements. The boundary conditions lead to a specific frequency equation and the eigenvalues from this provide the natural frequencies of the orbiting flexible motorised tether when static, accelerating in monotonic spin, and at terminal angular velocity. A rotation transformation matrix has been utilised to get the position vectors of the system's components in an assumed inertial frame. Spatio-temporal coordinates are transformed to modal coordinates before applying Lagrange's equations, and pre-selected linear modes are included to generate the equations of motion. The equations of motion contain inertial nonlinearities which are essentially of cubic order, and these show the potential for intricate intermodal coupling effects. A simulation of planar and non-planar motions has been undertaken and the differences in the modal responses, for both motions, and between the rigid body and flexible models are highlighted and discussed.
Ligterink, N.E.
2007-01-01
Functional system dynamics is the analysis, modelling, and simulation of continuous systems usually described by partial differential equations. From the infinite degrees of freedom of such systems only a finite number of relevant variables have to be chosen for a practical model description. The
Spin dynamics in a two-dimensional quantum gas
DEFF Research Database (Denmark)
Pedersen, Poul Lindholm; Gajdacz, Miroslav; Deuretzbacher, Frank
2014-01-01
We have investigated spin dynamics in a two-dimensional quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions with superimp......We have investigated spin dynamics in a two-dimensional quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions...... with nonlocal Einstein-Podolsky-Rosen entanglement....
Valentin, J; Sprenger, M; Pflüger, D; Röhrle, O
2018-02-10
Investigating the interplay between muscular activity and motion is the basis to improve our understanding of healthy or diseased musculoskeletal systems. To be able to analyze the musculoskeletal systems, computational models are employed. Albeit some severe modeling assumptions, almost all existing musculoskeletal system simulations appeal to multi-body simulation frameworks. Although continuum-mechanical musculoskeletal system models can compensate for some of these limitations, they are essentially not considered due to their computational complexity and cost. The proposed framework is the first activation-driven musculoskeletal system model, in which the exerted skeletal muscle forces are computed using three-dimensional, continuum-mechanical skeletal muscle models and in which muscle activations are determined based on a constraint optimization problem. Numerical feasibility is achieved by computing sparse grid surrogates with hierarchical B-splines, and adaptive sparse grid refinement further reduces the computational effort. The choice of B-splines allows the use of all existing gradient-based optimization techniques without further numerical approximation. This paper demonstrates that the resulting surrogates have low relative errors (less than 0.76%) and can be used within forward simulations that are subject to constraint optimization. To demonstrate this, we set up several different test scenarios in which an upper limb model consisting of the elbow joint, the biceps and triceps brachii and an external load is subjected to different optimization criteria. Even though this novel method has only been demonstrated for a two-muscle system, it can easily be extended to musculoskeletal systems with three or more muscles. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
Three-Dimensional Computational Fluid Dynamics
Energy Technology Data Exchange (ETDEWEB)
Haworth, D.C.; O' Rourke, P.J.; Ranganathan, R.
1998-09-01
Computational fluid dynamics (CFD) is one discipline falling under the broad heading of computer-aided engineering (CAE). CAE, together with computer-aided design (CAD) and computer-aided manufacturing (CAM), comprise a mathematical-based approach to engineering product and process design, analysis and fabrication. In this overview of CFD for the design engineer, our purposes are three-fold: (1) to define the scope of CFD and motivate its utility for engineering, (2) to provide a basic technical foundation for CFD, and (3) to convey how CFD is incorporated into engineering product and process design.
Study on three dimensional seismic isolation system
International Nuclear Information System (INIS)
Morishita, Masaki; Kitamura, Seiji
2003-01-01
Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R and D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the three-dimensional seismic isolation technologies, and the results of this year's study are summarized in the following five aspects. (1) Study on Earthquake Condition for Developing 3-dimensional Base Isolation System. The case study S2 is one of the maximum ground motions, of which the records were investigated up to this time. But a few observed near the fault exceed the case study S2 in the long period domain, depending on the fault length and conditions. Generally it is appropriate that the response spectra ratio (vertical/horizontal) is 0.6. (2) Performance Requirement for 3-dimensional Base Isolation System and Devices. Although the integrity map of main equipment/piping dominate the design criteria for the 3-dimensional base isolation system, the combined integrity map is the same as those of FY 2000, which are under fv=1Hz and over hv=20%. (3) Developing Targets and Schedule for 3-dimensional Isolation Technology. The target items for 3-dimensional base isolation system were rearranged into a table, and developing items to be examined concerning the device were also adjusted. A development plan until FY 2009 was made from the viewpoint of realization and establishment of a design guideline on 3-dimensional base isolation system. (4) Study on 3-dimensional Entire Building Base Isolation System. Three ideas among six ideas that had been proposed in FY2001, i.e., '3-dimensional base isolation system incorporating hydraulic
Dynamics of Information Systems
Hirsch, Michael J; Murphey, Robert
2010-01-01
Our understanding of information and information dynamics has outgrown classical information theory. This book presents the research explaining the importance of information in the evolution of a distributed or networked system. It presents techniques for measuring the value or significance of information within the context of a system
Dynamical systems generated by linear maps
Dolićanin, Ćemal B
2014-01-01
The book deals with dynamical systems, generated by linear mappings of finite dimensional spaces and their applications. These systems have a relatively simple structure from the point of view of the modern dynamical systems theory. However, for the dynamical systems of this sort, it is possible to obtain explicit answers to specific questions being useful in applications. The considered problems are natural and look rather simple, but in reality in the course of investigation, they confront users with plenty of subtle questions, and their detailed analysis needs a substantial effort. The problems arising are related to linear algebra and dynamical systems theory, and therefore, the book can be considered as a natural amplification, refinement and supplement to linear algebra and dynamical systems theory textbooks.
Nonlinear dynamic characterization of two-dimensional materials
Davidovikj, D.; Alijani, F.; Cartamil Bueno, S.J.; van der Zant, H.S.J.; Amabili, M.; Steeneken, P.G.
2017-01-01
Owing to their atomic-scale thickness, the resonances of two-dimensional (2D) material membranes show signatures of nonlinearities at forces of only a few picoNewtons. Although the linear dynamics of membranes is well understood, the exact relation between the nonlinear response and the resonator's
Complex dynamical invariants for two-dimensional complex potentials
Indian Academy of Sciences (India)
Abstract. Complex dynamical invariants are searched out for two-dimensional complex poten- tials using rationalization method within the framework of an extended complex phase space characterized by x = x1 + ip3, y = x2 + ip4, px = p1 + ix3, py = p2 + ix4. It is found that the cubic oscillator and shifted harmonic oscillator ...
Dynamics of cosmic strings with higher-dimensional windings
Energy Technology Data Exchange (ETDEWEB)
Yamauchi, Daisuke [Research Center for the Early Universe, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Lake, Matthew J. [The Institute for Fundamental Study, “The Tah Poe Academia Institute' , Naresuan University, Phitsanulok 65000 (Thailand); Thailand Center of Excellence in Physics, Ministry of Education,Bangkok 10400 (Thailand)
2015-06-11
We consider F-strings with arbitrary configurations in the Minkowski directions of a higher-dimensional spacetime, which also wrap and spin around S{sup 1} subcycles of constant radius in an arbitrary internal manifold, and determine the relation between the higher-dimensional and the effective four-dimensional quantities that govern the string dynamics. We show that, for any such configuration, the motion of the windings in the compact space may render the string effectively tensionless from a four-dimensional perspective, so that it remains static with respect to the large dimensions. Such a critical configuration occurs when (locally) exactly half the square of the string length lies in the large dimensions and half lies in the compact space. The critical solution is then seen to arise as a special case, in which the wavelength of the windings is equal to their circumference. As examples, long straight strings and circular loops are considered in detail, and the solutions to the equations of motion that satisfy the tensionless condition are presented. These solutions are then generalized to planar loops and arbitrary three-dimensional configurations. Under the process of dimensional reduction, in which higher-dimensional motion is equivalent to an effective worldsheet current (giving rise to a conserved charge), this phenomenon may be seen as the analogue of the tensionless condition which arises for superconducting and chiral-current carrying cosmic strings.
Dynamics of cosmic strings with higher-dimensional windings
International Nuclear Information System (INIS)
Yamauchi, Daisuke; Lake, Matthew J.
2015-01-01
We consider F-strings with arbitrary configurations in the Minkowski directions of a higher-dimensional spacetime, which also wrap and spin around S 1 subcycles of constant radius in an arbitrary internal manifold, and determine the relation between the higher-dimensional and the effective four-dimensional quantities that govern the string dynamics. We show that, for any such configuration, the motion of the windings in the compact space may render the string effectively tensionless from a four-dimensional perspective, so that it remains static with respect to the large dimensions. Such a critical configuration occurs when (locally) exactly half the square of the string length lies in the large dimensions and half lies in the compact space. The critical solution is then seen to arise as a special case, in which the wavelength of the windings is equal to their circumference. As examples, long straight strings and circular loops are considered in detail, and the solutions to the equations of motion that satisfy the tensionless condition are presented. These solutions are then generalized to planar loops and arbitrary three-dimensional configurations. Under the process of dimensional reduction, in which higher-dimensional motion is equivalent to an effective worldsheet current (giving rise to a conserved charge), this phenomenon may be seen as the analogue of the tensionless condition which arises for superconducting and chiral-current carrying cosmic strings
System dynamics with interaction discontinuity
Luo, Albert C J
2015-01-01
This book describes system dynamics with discontinuity caused by system interactions and presents the theory of flow singularity and switchability at the boundary in discontinuous dynamical systems. Based on such a theory, the authors address dynamics and motion mechanism of engineering discontinuous systems due to interaction. Stability and bifurcations of fixed points in nonlinear discrete dynamical systems are presented, and mapping dynamics are developed for analytical predictions of periodic motions in engineering discontinuous dynamical systems. Ultimately, the book provides an alternative way to discuss the periodic and chaotic behaviors in discontinuous dynamical systems.
An introduction to dynamical systems.
Sobie, Eric A
2011-09-13
This Teaching Resource provides lecture notes, slides, and a problem set that can assist in teaching concepts related to dynamical systems tools for the analysis of ordinary differential equation (ODE)-based models. The concepts are applied to familiar biological problems, and the material is appropriate for graduate students or advanced undergraduates. The lecture explains how equations describing biochemical signaling networks can be derived from diagrams that illustrate the reactions in graphical form. Because such reactions are most frequently described using systems of ODEs, the lecture discusses and illustrates the principles underlying the numerical solution of ODEs. Methods for determining the stability of steady-state solutions of one or two-dimensional ODE systems are covered and illustrated using standard graphical methods. The concept of a bifurcation, a condition at which a system's behavior changes qualitatively, is also introduced. A problem set is included that (i) requires students to implement an ODE model of biochemical reactions using MATLAB and (ii) allows them to explore dynamical systems concepts.
Turbulence and Dynamical Systems.
1984-12-31
Dynamical Systems 16. ASBTRACT (Continue on reverse if nemcry and idinitiy by block number) Abstract enclosed. See page 7. iyD, C FILE COZY ... 20... mysterious long-time f behavior of the Euler equation in fluid mechanics. The talk Final Report - APOSR page 2 of C. Schwarz on liquid helium showed to
Controlling Uncertain Dynamical Systems
Indian Academy of Sciences (India)
... Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 9. Controlling Uncertain Dynamical Systems - Basic Ideas of Adaptive Control. N Ananthkrishnan Rashi Bansal.
Butschli Dynamic Droplet System
DEFF Research Database (Denmark)
Armstrong, R.; Hanczyc, M.
2013-01-01
Dynamical oil-water systems such as droplets display lifelike properties and may lend themselves to chemical programming to perform useful work, specifically with respect to the built environment. We present Butschli water-in-oil droplets as a model for further investigation into the development ...
Decoherence dynamics in interferometry with one-dimensional bose-einstein condensates
DEFF Research Database (Denmark)
Schumm, Thorsten; Hofferberth, Sebastian; Schmiedmayer, Jörg
2007-01-01
We perform interferometry with one-dimensional Bose-Einstein condensates in a double well potential. Using dressed adiabatic potentials on an atomchip, we dynamically split BECs, imposing a macroscopic coherence on the system. Fluctuations of the order parameter are revealed as local shifts in th...
Information Processing Capacity of Dynamical Systems
Dambre, Joni; Verstraeten, David; Schrauwen, Benjamin; Massar, Serge
2012-07-01
Many dynamical systems, both natural and artificial, are stimulated by time dependent external signals, somehow processing the information contained therein. We demonstrate how to quantify the different modes in which information can be processed by such systems and combine them to define the computational capacity of a dynamical system. This is bounded by the number of linearly independent state variables of the dynamical system, equaling it if the system obeys the fading memory condition. It can be interpreted as the total number of linearly independent functions of its stimuli the system can compute. Our theory combines concepts from machine learning (reservoir computing), system modeling, stochastic processes, and functional analysis. We illustrate our theory by numerical simulations for the logistic map, a recurrent neural network, and a two-dimensional reaction diffusion system, uncovering universal trade-offs between the non-linearity of the computation and the system's short-term memory.
Information Processing Capacity of Dynamical Systems
Dambre, Joni; Verstraeten, David; Schrauwen, Benjamin; Massar, Serge
2012-01-01
Many dynamical systems, both natural and artificial, are stimulated by time dependent external signals, somehow processing the information contained therein. We demonstrate how to quantify the different modes in which information can be processed by such systems and combine them to define the computational capacity of a dynamical system. This is bounded by the number of linearly independent state variables of the dynamical system, equaling it if the system obeys the fading memory condition. It can be interpreted as the total number of linearly independent functions of its stimuli the system can compute. Our theory combines concepts from machine learning (reservoir computing), system modeling, stochastic processes, and functional analysis. We illustrate our theory by numerical simulations for the logistic map, a recurrent neural network, and a two-dimensional reaction diffusion system, uncovering universal trade-offs between the non-linearity of the computation and the system's short-term memory. PMID:22816038
Kantowski-Sachs multidimensional cosmological models and dynamical dimensional reduction
International Nuclear Information System (INIS)
Demianski, M.; Rome Univ.; Golda, Z.A.; Heller, M.; Szydlowski, M.
1988-01-01
Einstein's field equations are solved for a multidimensional spacetime (KS) x Tsup(m), where (KS) is a four-dimensional Kantowski-Sachs spacetime and Tsup(m) is an m-dimensional torus. Among all possible vacuum solutions there is a large class of spacetimes in which the macroscopic space expands and the microscopic space contracts to a finite volume. We also consider a non-vacuum case and we explicitly solve the field equations for the matter satisfying the Zel'dovich equation of state. In non-vacuum models, with matter satisfying an equation of state p = γρ, O ≤ γ < 1, at a sufficiently late stage of evolution the microspace always expands and the dynamical dimensional reduction does not occur. (author)
The two-dimensional reactor dynamics program TINTE. Pt. 2
International Nuclear Information System (INIS)
Gerwin, H.
1989-02-01
The TINTE code system deals with the nuclear and the thermal transient behaviour of the primary circuit of an HTGR taking into consideration the mutual feedback effects in two-dimensional r-z geometry. In Part One of this report (Juel-2167) the initial equations were compiled and methods of solution discussed. In an appendix to this second part they are completed by some supplementary points. The TINTE code construction and a detailed input description will be discussed in Part Three. The Part Two shows examples of application, especially a comparative calculation of dynamic experiments performed at the AVR. A good agreement between calculational and experimental results is found. Further examples show the flexibility of TINTE: first of all, individual moduli of TINTE are used to find a solution to a thermofluid problem. In addition TINTE is used to demonstrate the mutual feedback between nuclear and thermal processes in process heat reactors, including those with natural convective conditions, without any control rod movement. (orig.) [de
Plasmoid Chain Dynamics in Three-Dimensional Kinetic Simulations
Markidis, S.; Henri, P.; Lapenta, G.; Divin, A.; Goldman, M.; Newman, D.; Laure, E.
2013-10-01
We study the dynamics of a plasmoid chain with three dimensional Particle-in-Cell simulations. The evolution of the system with and without a uniform guide field, whose strength is 1/3 the asymptotic magnetic field, is investigated. The plasmoid chain forms by spontaneous magnetic reconnection: the tearing instability rapidly disrupts the initial current sheet generating several small-scale plasmoids, that rapidly grow in size coalescing and kinking. The plasmoid kink is mainly driven by the coalescence process. The presence of guide field strongly influences the evolution of the plasmoid chain. Without a guide field, a main reconnection site dominates and smaller reconnection regions are included in larger ones, leading to an hierarchical structure of the plasmoid-dominated current sheet. On the contrary in presence of a guide field, plasmoids have approximately the same size and the hierarchical structure does not emerge, a strong core magnetic field develops in the center of the plasmoid in the direction of the existing guide field, and bump-on-tail instability, leading to the formation of electron holes, is detected in proximity of the plasmoids. The present work is supported by NASA MMS Grant NNX08AO84G. Additional support rom the European Commission's Seventh Framework Programme under the grant agreement no. 287703 (CRESTA, cresta-project.eu).
Implementation of one-dimensional domain wall dynamics simulator
Kim, Hyungsuk; Heo, Seo Weon; You, Chun-Yeol
2017-12-01
We implemented a one-dimensional domain wall (DW) dynamics simulator based on the well-developed collective coordinate approach to demonstrate DW motion under a given magnetic field and/or current flow. The simulator adopted all known influences, including three-dimensional external magnetic fields, spin transfer torque with non-adiabatic contribution, spin Hall effect, Rashba effect, and Dzyaloshinskii-Moriya interaction. The simulator can calculate the position, velocity, internal magnetization angle, and tilting angle of the domain wall to the current direction or wire axis under given simulation conditions and material parameters. It will not only provide physical insights of domain wall dynamics to experimentalists, but also can be used to more easily simulate various physical circumstances before running time-consuming micromagnetic simulations or real experiments.
Canonical and symplectic analysis for three dimensional gravity without dynamics
International Nuclear Information System (INIS)
Escalante, Alberto; Osmart Ochoa-Gutiérrez, H.
2017-01-01
In this paper a detailed Hamiltonian analysis of three-dimensional gravity without dynamics proposed by V. Hussain is performed. We report the complete structure of the constraints and the Dirac brackets are explicitly computed. In addition, the Faddeev–Jackiw symplectic approach is developed; we report the complete set of Faddeev–Jackiw constraints and the generalized brackets, then we show that the Dirac and the generalized Faddeev–Jackiw brackets coincide to each other. Finally, the similarities and advantages between Faddeev–Jackiw and Dirac’s formalism are briefly discussed. - Highlights: • We report the symplectic analysis for three dimensional gravity without dynamics. • We report the Faddeev–Jackiw constraints. • A pure Dirac’s analysis is performed. • The complete structure of Dirac’s constraints is reported. • We show that symplectic and Dirac’s brackets coincide to each other.
Canonical and symplectic analysis for three dimensional gravity without dynamics
Energy Technology Data Exchange (ETDEWEB)
Escalante, Alberto, E-mail: aescalan@ifuap.buap.mx [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48 72570, Puebla, Pue. (Mexico); Osmart Ochoa-Gutiérrez, H. [Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Apartado postal 1152, 72001 Puebla, Pue. (Mexico)
2017-03-15
In this paper a detailed Hamiltonian analysis of three-dimensional gravity without dynamics proposed by V. Hussain is performed. We report the complete structure of the constraints and the Dirac brackets are explicitly computed. In addition, the Faddeev–Jackiw symplectic approach is developed; we report the complete set of Faddeev–Jackiw constraints and the generalized brackets, then we show that the Dirac and the generalized Faddeev–Jackiw brackets coincide to each other. Finally, the similarities and advantages between Faddeev–Jackiw and Dirac’s formalism are briefly discussed. - Highlights: • We report the symplectic analysis for three dimensional gravity without dynamics. • We report the Faddeev–Jackiw constraints. • A pure Dirac’s analysis is performed. • The complete structure of Dirac’s constraints is reported. • We show that symplectic and Dirac’s brackets coincide to each other.
Emergence in Dynamical Systems
Directory of Open Access Journals (Sweden)
John Collier
2013-12-01
Full Text Available Emergence is a term used in many contexts in current science; it has become fashionable. It has a traditional usage in philosophy that started in 1875 and was expanded by J. S. Mill (earlier, under a different term and C. D. Broad. It is this form of emergence that I am concerned with here. I distinguish it from uses like ‘computational emergence,’ which can be reduced to combinations of program steps, or its application to merely surprising new features that appear in complex combinations of parts. I will be concerned specifically with ontological emergence that has the logical properties required by Mill and Broad (though there might be some quibbling about the details of their views. I restrict myself to dynamical systems that are embodied in processes. Everything that we can interact with through sensation or action is either dynamical or can be understood in dynamical terms, so this covers all comprehensible forms of emergence in the strong (nonreducible sense I use. I will give general dynamical conditions that underlie the logical conditions traditionally assigned to emergence in nature.The advantage of this is that, though we cannot test logical conditions directly, we can test dynamical conditions. This gives us an empirical and realistic form of emergence, contrary those who say it is a matter of perspective.
Dimensionality reduction of bistable biological systems.
Zakharova, A; Nikoloski, Z; Koseska, A
2013-03-01
Time hierarchies, arising as a result of interactions between system's components, represent a ubiquitous property of dynamical biological systems. In addition, biological systems have been attributed switch-like properties modulating the response to various stimuli across different organisms and environmental conditions. Therefore, establishing the interplay between these features of system dynamics renders itself a challenging question of practical interest in biology. Existing methods are suitable for systems with one stable steady state employed as a well-defined reference. In such systems, the characterization of the time hierarchies has already been used for determining the components that contribute to the dynamics of biological systems. However, the application of these methods to bistable nonlinear systems is impeded due to their inherent dependence on the reference state, which in this case is no longer unique. Here, we extend the applicability of the reference-state analysis by proposing, analyzing, and applying a novel method, which allows investigation of the time hierarchies in systems exhibiting bistability. The proposed method is in turn used in identifying the components, other than reactions, which determine the systemic dynamical properties. We demonstrate that in biological systems of varying levels of complexity and spanning different biological levels, the method can be effectively employed for model simplification while ensuring preservation of qualitative dynamical properties (i.e., bistability). Finally, by establishing a connection between techniques from nonlinear dynamics and multivariate statistics, the proposed approach provides the basis for extending reference-based analysis to bistable systems.
Interactive Dynamic-System Simulation
Korn, Granino A
2010-01-01
Showing you how to use personal computers for modeling and simulation, Interactive Dynamic-System Simulation, Second Edition provides a practical tutorial on interactive dynamic-system modeling and simulation. It discusses how to effectively simulate dynamical systems, such as aerospace vehicles, power plants, chemical processes, control systems, and physiological systems. Written by a pioneer in simulation, the book introduces dynamic-system models and explains how software for solving differential equations works. After demonstrating real simulation programs with simple examples, the author
Photoinduced charge-order melting dynamics in a one-dimensional interacting Holstein model
Hashimoto, Hiroshi; Ishihara, Sumio
2017-07-01
Transient quantum dynamics in an interacting fermion-phonon system are investigated with a focus on a charge order (CO) melting after a short optical-pulse irradiation and the roles of the quantum phonons in the transient dynamics. A spinless-fermion model in a one-dimensional chain coupled with local phonons is analyzed numerically. The infinite time-evolving block decimation algorithm is adopted as a reliable numerical method for one-dimensional quantum many-body systems. Numerical results for the photoinduced CO melting dynamics without phonons are well interpreted by the soliton picture for the CO domains. This interpretation is confirmed by numerical simulation of an artificial local excitation and the classical soliton model. In the case of large phonon frequencies corresponding to the antiadiabatic condition, CO melting is induced by propagations of the polaronic solitons with the renormalized soliton velocity. On the other hand, in the case of small phonon frequencies corresponding to the adiabatic condition, the first stage of the CO melting dynamics occurs due to the energy transfer from the fermionic to phononic systems, and the second stage is brought about by the soliton motions around the bottom of the soliton band. The analyses provide a standard reference for photoinduced CO melting dynamics in one-dimensional many-body quantum systems.
Hirata, Yoshito; Aihara, Kazuyuki
2012-06-01
We introduce a low-dimensional description for a high-dimensional system, which is a piecewise affine model whose state space is divided by permutations. We show that the proposed model tends to predict wind speeds and photovoltaic outputs for the time scales from seconds to 100 s better than by global affine models. In addition, computations using the piecewise affine model are much faster than those of usual nonlinear models such as radial basis function models.
Wisdom, Jack
2002-01-01
In these 18 years, the research has touched every major dynamical problem in the solar system, including: the effect of chaotic zones on the distribution of asteroids, the delivery of meteorites along chaotic pathways, the chaotic motion of Pluto, the chaotic motion of the outer planets and that of the whole solar system, the delivery of short period comets from the Kuiper belt, the tidal evolution of the Uranian arid Galilean satellites, the chaotic tumbling of Hyperion and other irregular satellites, the large chaotic variations of the obliquity of Mars, the evolution of the Earth-Moon system, and the resonant core- mantle dynamics of Earth and Venus. It has introduced new analytical and numerical tools that are in widespread use. Today, nearly every long-term integration of our solar system, its subsystems, and other solar systems uses algorithms that was invented. This research has all been primarily Supported by this sequence of PGG NASA grants. During this period published major investigations of tidal evolution of the Earth-Moon system and of the passage of the Earth and Venus through non-linear core-mantle resonances were completed. It has published a major innovation in symplectic algorithms: the symplectic corrector. A paper was completed on non-perturbative hydrostatic equilibrium.
The Three Dimensional Structure and Dynamics of Magnetotail Reconnection
Walker, Raymond; Lapenta, Giovanni; Liang, Haoming; El Alaoui, Mostafa; Berchem, Jean; Goldstein, Melvyn
2017-04-01
Magnetic reconnection is a fundamental process by which magnetic energy is dissipated and converted into particle energy. In the next few months the Magnetosphere Multi-Scale Mission (MMS) will provide high resolution observations of reconnection and its consequences in the magnetotail. Of high priority will be observations of the electron diffusion region (EDR) where the actual process of reconnection is thought to occur. In preparation for the MMS observations we have investigated tail reconnection in a realistic magnetospheric configuration by using a new approach that combines a global magnetohydrodynamic simulation of the solar wind, magnetosphere and ionosphere system with a large scale (30X12X12RE) implicit particle-in-cell (iPic3D) simulation (see Lapenta et al., 2016 Geophys. Res. Lett. 43, 515-524, doi:10.1002/2015GL066689 for a discussion of the technique). In particular we have investigated the three dimensional structure and dynamics of tail reconnection during a substorm on February 15, 2008. We found that just earthward of the reconnection site the tail becomes highly structured in the Y direction in the GSM coordinate system. The structures result from an instability associated with strong shear flows in the Y direction within the current sheet. In particular we found that the work done by the magnetic field J•E in the electron frame alternated between positive and negative although the net J•E was positive. We used several methods for identifying the EDR (non-gyrotropy, slippage, the non-ideal terms in OHM's law as well as J•E) and found that all gave false positive results in some regions of the tail. However all of the approaches gave positive results in some of the small structures with J•E positive. These putative EDRs extended ( 2di, >1di, 1di) in the X, Y and Z directions.
Three dimensional electrochemical system for neurobiological studies
DEFF Research Database (Denmark)
Vazquez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith
2009-01-01
In this work we report a novel three dimensional electrode array for electrochemical measurements in neuronal studies. The main advantage of working with these out-of-plane structures is the enhanced sensitivity of the system in terms of measuring electrochemical changes in the environment...
REVIEW One-Dimensional Dynamical Modeling of Earthquakes: A Review
Directory of Open Access Journals (Sweden)
Jeen-Hwa Wang
2008-01-01
Full Text Available Studies of the power-law relations of seismicity and earthquake source parameters based on the one-dimensional (1-D Burridge-Knopoff¡¦s (BK dynamical lattice model, especially those studies conducted by Taiwan¡¦s scientists, are reviewed in this article. In general, velocity- and/or state-dependent friction is considered to control faulting. A uniform distribution of breaking strengths (i.e., the static friction strength is taken into account in some studies, and inhomogeneous distributions in others. The scaling relations in these studies include: Omori¡¦s law, the magnitude-frequency or energy-frequency relation, the relation between source duration time and seismic moment, the relation between rupture length and seismic moment, the frequency-length relation, and the source power spectra. The main parameters of the one-dimensional (1-D Burridge-Knopoff¡¦s (BK dynamical lattice model include: the decreasing rate (r of dynamic friction strength with sliding velocity; the type and degree of heterogeneous distribution of the breaking strengths, the stiffness ratio (i.e., the ratio between the stiffness of the coil spring connecting two mass elements and that of the leaf spring linking a mass element and the moving plate; the frictional drop ratio of the minimum dynamic friction strength to the breaking strength; and the maximum breaking strength. For some authors, the distribution of the breaking strengths was considered to be a fractal function. Hence, the fractal dimension of such a distribution is also a significant parameter. Comparison between observed scaling laws and simulation results shows that the 1-D BK dynamical lattice model acceptably approaches fault dynamics.
Visualizing dimensionality reduction of systems biology data
Lehrmann, Andreas; Huber, Michael; Polatkan, Aydin C.; Pritzkau, Albert; Nieselt, Kay
2012-01-01
One of the challenges in analyzing high-dimensional expression data is the detection of important biological signals. A common approach is to apply a dimension reduction method, such as principal component analysis. Typically, after application of such a method the data is projected and visualized in the new coordinate system, using scatter plots or profile plots. These methods provide good results if the data have certain properties which become visible in the new coordinate system and which...
Dynamics of vortex interactions in two-dimensional flows
DEFF Research Database (Denmark)
Juul Rasmussen, J.; Nielsen, A.H.; Naulin, V.
2002-01-01
The dynamics and interaction of like-signed vortex structures in two dimensional flows are investigated by means of direct numerical solutions of the two-dimensional Navier-Stokes equations. Two vortices with distributed vorticity merge when their distance relative to their radius, d/R-0l. is below...... a critical value, a(c). Using the Weiss-field, a(c) is estimated for vortex patches. Introducing an effective radius for vortices with distributed vorticity, we find that 3.3 ... is effectively producing small scale structures and the relation to the enstrophy "cascade" in developed 2D turbulence is discussed. The influence of finite viscosity on the merging is also investigated. Additionally, we examine vortex interactions on a finite domain, and discuss the results in connection...
Setting the Scale of Dimensional Reduction in Causal Dynamical Triangulations
Cooperman, Joshua
2011-04-01
Within the causal dynamical triangulations approach to quantization of gravity, striking evidence has emerged that the effective dimensionality of spacetime dynamically reduces at small scales. Specifically, in the case of topological sphericity, the expectation value of the spectral dimension decreases with the scale being probed from the topological value of four to an apparent value of two. Thus far the physical scale at which this dynamical dimensional reduction occurs has not been ascertained. In this talk I present the first determinations of this scale. By fitting the expectation value of the spacetime geometry to a classical minisuperspace model, I extract the triangulation lattice spacing in units of the Planck length and the effective cosmological constant in units of the inverse Planck length squared. The former value allows me to establish directly the scales probed by the random walk that defines the spectral dimension. The latter value allows me to establish indirectly these scales via the heat trace for the minisuperspace geometry. This work also yields preliminary indications of the flow of the cosmological constant within this model of quantum geometry.
Cosmological dynamical systems
Leon, Genly
2011-01-01
In this book are studied, from the perspective of the dynamical systems, several Universe models. In chapter 1 we give a bird's eye view on cosmology and cosmological problems. Chapter 2 is devoted to a brief review on some results and useful tools from the qualitative theory of dynamical systems. They provide the theoretical basis for the qualitative study of concrete cosmological models. Chapters 1 and 2 are a review of well-known results. Chapters 3, 4, 5 and 6 are devoted to our main results. In these chapters are extended and settled in a substantially different, more strict mathematical language, several results obtained by one of us in arXiv:0812.1013 [gr-qc]; arXiv:1009.0689 [gr-qc]; arXiv:0904.1577[gr-qc]; and arXiv:0909.3571 [hep-th]. In chapter 6, we provide a different approach to the subject discussed in astro-ph/0503478. Additionally, we perform a Poincar\\'e compactification process allowing to construct a global phase space containing all the cosmological information in both finite and infinite...
Parallel solution of sparse one-dimensional dynamic programming problems
Nicol, David M.
1989-01-01
Parallel computation offers the potential for quickly solving large computational problems. However, it is often a non-trivial task to effectively use parallel computers. Solution methods must sometimes be reformulated to exploit parallelism; the reformulations are often more complex than their slower serial counterparts. We illustrate these points by studying the parallelization of sparse one-dimensional dynamic programming problems, those which do not obviously admit substantial parallelization. We propose a new method for parallelizing such problems, develop analytic models which help us to identify problems which parallelize well, and compare the performance of our algorithm with existing algorithms on a multiprocessor.
Dynamics of stochastic systems
Klyatskin, Valery I
2005-01-01
Fluctuating parameters appear in a variety of physical systems and phenomena. They typically come either as random forces/sources, or advecting velocities, or media (material) parameters, like refraction index, conductivity, diffusivity, etc. The well known example of Brownian particle suspended in fluid and subjected to random molecular bombardment laid the foundation for modern stochastic calculus and statistical physics. Other important examples include turbulent transport and diffusion of particle-tracers (pollutants), or continuous densities (''''oil slicks''''), wave propagation and scattering in randomly inhomogeneous media, for instance light or sound propagating in the turbulent atmosphere.Such models naturally render to statistical description, where the input parameters and solutions are expressed by random processes and fields.The fundamental problem of stochastic dynamics is to identify the essential characteristics of system (its state and evolution), and relate those to the input parameters of ...
Dynamics of impurities in a three-dimensional volume-preserving map.
Das, Swetamber; Gupte, Neelima
2014-07-01
We study the dynamics of inertial particles in three-dimensional incompressible maps, as representations of volume-preserving flows. The impurity dynamics has been modeled, in the Lagrangian framework, by a six-dimensional dissipative bailout embedding map. The fluid-parcel dynamics of the base map is embedded in the particle dynamics governed by the map. The base map considered for the present study is the Arnold-Beltrami-Childress (ABC) map. We consider the behavior of the system both in the aerosol regime, where the density of the particle is larger than that of the base flow, as well as the bubble regime, where the particle density is less than that of the base flow. The phase spaces in both the regimes show rich and complex dynamics with three types of dynamical behaviors--chaotic structures, regular orbits, and hyperchaotic regions. In the one-action case, the aerosol regime is found to have periodic attractors for certain values of the dissipation and inertia parameters. For the aerosol regime of the two-action ABC map, an attractor merging and widening crisis is identified using the bifurcation diagram and the spectrum of Lyapunov exponents. After the crisis an attractor with two parts is seen, and trajectories hop between these parts with period 2. The bubble regime of the embedded map shows strong hyperchaotic regions as well as crisis induced intermittency with characteristic times between bursts that scale as a power law behavior as a function of the dissipation parameter. Furthermore, we observe a riddled basin of attraction and unstable dimension variability in the phase space in the bubble regime. The bubble regime in the one-action case shows similar behavior. This study of a simple model of impurity dynamics may shed light upon the transport properties of passive scalars in three-dimensional flows. We also compare our results with those seen earlier in two-dimensional flows.
Three Dimensional Quantized Vortex Dynamics in Superfluid Helium
Meichle, David; Megson, Peter; Lathrop, Daniel
2014-11-01
Vorticity is constrained to line-like topological defects in quantum superfluids, such as liquid Helium below the Lambda transition temperature of 2.17 Kelvin. A tangle of vortices exists in a dissipative dynamical state called quantum turbulence, which has quantitative features distinct from classical turbulence. To study the vortex dynamics, we have invented a novel method to disperse fluorescent nanoparticles directly into the superfluid which become trapped on the vortex cores. Using a newly constructed multi-camera stereographic microscope, we present new data showing vortex reconnections and Kelvin waves with fully three-dimensional particle trajectories. These events are of scientific interest as they play a key role in the dissipation of quantum turbulence.
Biofluid Dynamics in Cardiovascular System
Chung, Hansol; Yoo, Su Jung; Kyung, Richard
2011-11-01
Biofluid dynamics is characterized by the study of fluids in biological systems. Common biofluid systems include blood flow in the cardiovascular system and airflow in the lungs. The mathematical modeling of blood flow through the complex geometry of a prosthetic heart valve is a difficult task. In such a problem the complex geometries of the valve must be modeled properly so that they can be studied numerically. The present analysis is performed on a disk-type prosthetic heart valve. The valve is assumed to be in the aortic position and observed the structure of the valve cage influence the flow field near an aortic valve. For the purpose of mathematical modeling, the laminar incompressible two-dimensional steady flow of a homogeneous Newtonian fluid with constant viscosity is assumed. The flow is considered during the greater part of systole when the valve is fully open. Convergent numerical solutions are obtained for Reynolds numbers of 30, 180, 900 and 4500. Stream function, horizontal velocity, vertical velocity and shear stress solutions are computed at every grid point.
Exactly integrable analogue of a one-dimensional gravitating system
International Nuclear Information System (INIS)
Miller, Bruce N.; Yawn, Kenneth R.; Maier, Bill
2005-01-01
Exchange symmetry in acceleration partitions the configuration space of an N particle one-dimensional gravitational system (OGS) into N! equivalent cells. We take advantage of the resulting small angular separation between the forces in neighboring cells to construct a related integrable version of the system that takes the form of a central force problem in N-1 dimensions. The properties of the latter, including the construction of trajectories and possible continuum limits, are developed. Dynamical simulation is employed to compare the two models. For some initial conditions, excellent agreement is observed
Lai, Bang-Cheng; He, Jian-Jun
2018-03-01
In this paper, we construct a novel 4D autonomous chaotic system with four cross-product nonlinear terms and five equilibria. The multiple coexisting attractors and the multiscroll attractor of the system are numerically investigated. Research results show that the system has various types of multiple attractors, including three strange attractors with a limit cycle, three limit cycles, two strange attractors with a pair of limit cycles, two coexisting strange attractors. By using the passive control theory, a controller is designed for controlling the chaos of the system. Both analytical and numerical studies verify that the designed controller can suppress chaotic motion and stabilise the system at the origin. Moreover, an electronic circuit is presented for implementing the chaotic system.
Dimensional control of defect dynamics in perovskite oxide superlattices
Bredeson, Isaac; Zhang, Lipeng; Kent, P. R. C.; Cooper, Valentino R.; Xu, Haixuan
2018-03-01
Point defects play a critical role in the structural, physical, and interfacial properties of perovskite oxide superlattices. However, understanding of the fundamental properties of point defects in superlattices, especially their transport properties, is rather limited. Here, we report predictions of the stability and dynamics of oxygen vacancies in SrTi O3/PbTi O3 oxide superlattices using first-principles calculations in combination with the kinetic Monte Carlo method. By varying the stacking period, i.e., changing of n in n STO /n PTO , we discover a crossover from three-dimensional diffusion to primarily two-dimensional planar diffusion. Such planar diffusion may lead to novel designs of ionic conductors. We show that the dominant vacancy position may vary in the superlattices, depending on the superlattice structure and stacking period, contradicting the common assumption that point defects reside at interfaces. Moreover, we predict a significant increase in room-temperature ionic conductivity for 3STO/3PTO relative to the bulk phases. Considering the variety of cations that can be accommodated in perovskite superlattices and the potential mismatch of spin, charge, and orbitals at the interfaces, this paper identifies a pathway to control defect dynamics for technological applications.
Chaos of discrete dynamical systems in complete metric spaces
International Nuclear Information System (INIS)
Shi Yuming; Chen Guanrong
2004-01-01
This paper is concerned with chaos of discrete dynamical systems in complete metric spaces. Discrete dynamical systems governed by continuous maps in general complete metric spaces are first discussed, and two criteria of chaos are then established. As a special case, two corresponding criteria of chaos for discrete dynamical systems in compact subsets of metric spaces are obtained. These results have extended and improved the existing relevant results of chaos in finite-dimensional Euclidean spaces
Exciton Dynamics, Transport, and Annihilation in Atomically Thin Two-Dimensional Semiconductors.
Yuan, Long; Wang, Ti; Zhu, Tong; Zhou, Mingwei; Huang, Libai
2017-07-20
Large binding energy and unique exciton fine structure make the transition metal dichalcogenides (TMDCs) an ideal platform to study exciton behaviors in two-dimensional (2D) systems. While excitons in these systems have been extensively researched, there currently lacks a consensus on mechanisms that control dynamics. In this Perspective, we discuss extrinsic and intrinsic factors in exciton dynamics, transport, and annihilation in 2D TMDCs. Intrinsically, dark and bright exciton energy splitting is likely to play a key role in modulating the dynamics. Extrinsically, defect scattering is prevalent in single-layer TMDCs, which leads to rapid picosecond decay and limits exciton transport. The exciton-exciton annihilation process in single-layer TMDCs is highly efficient, playing an important role in the nonradiative recombination rate in the high exciton density regime. Future challenges and opportunities to control exciton dynamics are discussed.
Two-dimensional topological photonic systems
Sun, Xiao-Chen; He, Cheng; Liu, Xiao-Ping; Lu, Ming-Hui; Zhu, Shi-Ning; Chen, Yan-Feng
2017-09-01
The topological phase of matter, originally proposed and first demonstrated in fermionic electronic systems, has drawn considerable research attention in the past decades due to its robust transport of edge states and its potential with respect to future quantum information, communication, and computation. Recently, searching for such a unique material phase in bosonic systems has become a hot research topic worldwide. So far, many bosonic topological models and methods for realizing them have been discovered in photonic systems, acoustic systems, mechanical systems, etc. These discoveries have certainly yielded vast opportunities in designing material phases and related properties in the topological domain. In this review, we first focus on some of the representative photonic topological models and employ the underlying Dirac model to analyze the edge states and geometric phase. On the basis of these models, three common types of two-dimensional topological photonic systems are discussed: 1) photonic quantum Hall effect with broken time-reversal symmetry; 2) photonic topological insulator and the associated pseudo-time-reversal symmetry-protected mechanism; 3) time/space periodically modulated photonic Floquet topological insulator. Finally, we provide a summary and extension of this emerging field, including a brief introduction to the Weyl point in three-dimensional systems.
Lecca, Paola; Mura, Ivan; Re, Angela; Barker, Gary C; Ihekwaba, Adaoha E C
2016-01-01
Chaotic behavior refers to a behavior which, albeit irregular, is generated by an underlying deterministic process. Therefore, a chaotic behavior is potentially controllable. This possibility becomes practically amenable especially when chaos is shown to be low-dimensional, i.e., to be attributable to a small fraction of the total systems components. In this case, indeed, including the major drivers of chaos in a system into the modeling approach allows us to improve predictability of the systems dynamics. Here, we analyzed the numerical simulations of an accurate ordinary differential equation model of the gene network regulating sporulation initiation in Bacillus subtilis to explore whether the non-linearity underlying time series data is due to low-dimensional chaos. Low-dimensional chaos is expectedly common in systems with few degrees of freedom, but rare in systems with many degrees of freedom such as the B. subtilis sporulation network. The estimation of a number of indices, which reflect the chaotic nature of a system, indicates that the dynamics of this network is affected by deterministic chaos. The neat separation between the indices obtained from the time series simulated from the model and those obtained from time series generated by Gaussian white and colored noise confirmed that the B. subtilis sporulation network dynamics is affected by low dimensional chaos rather than by noise. Furthermore, our analysis identifies the principal driver of the networks chaotic dynamics to be sporulation initiation phosphotransferase B (Spo0B). We then analyzed the parameters and the phase space of the system to characterize the instability points of the network dynamics, and, in turn, to identify the ranges of values of Spo0B and of the other drivers of the chaotic dynamics, for which the whole system is highly sensitive to minimal perturbation. In summary, we described an unappreciated source of complexity in the B. subtilis sporulation network by gathering
Topics in Extended Dynamical Systems
Bhagavatula, Ravi S.
This thesis consists of three chapters. Each chapter is self-contained and is devoted to the investigation of a particular topic in extended dynamical systems. In the first chapter, an approach based on Langevin equations is implemented to understand the non-Gaussian nature of the probability distribution function (PDF) of local diffusive variables in extended dynamical systems, e.g., a passive scalar advected by turbulent velocity fluctuations. Two mechanisms are proposed for the origin of non-Gaussian tails: One relies on the nature of temporal correlations of the fluctuations that couple additively to the diffusive field, leading to exponential and stretched exponential tails in the PDF; the other depends on multiplicative coupling between the diffusive field and the fluctuations, producing algebraic tails in the PDF. The mechanisms are illustrated using models for a passive scalar and also a current driven Josephson junction array. This study indicates that shapes of local PDFs in turbulent states are non-universal and crucially depend on local couplings and time scales. The second chapter establishes the existence of a class of locally conserving chaotic (deterministic) systems that exhibit Generic Scale Invariance--algebraic decay of spatial and temporal correlations without tuning parameters. This study also reveals the similarity between noise and chaos in extended systems as far as long-wavelength and long -time behavior is concerned. Specifically, a two dimensional coupled-map lattice model with a conserved density is numerically shown to exhibit, in agreement with heuristic arguments, algebraic decay of spatio-temporal correlations in chaotic states with simple predictable exponents. The third chapter investigates scaling behavior of earthquakes in seismic zone models in which an earthquake is modeled by a quasi-static description that ignores short -time dynamics during an earthquake. The models incorporate the essential feature of long-ranged stress
Synchronization dynamics of two different dynamical systems
International Nuclear Information System (INIS)
Luo, Albert C.J.; Min Fuhong
2011-01-01
Highlights: → Synchronization dynamics of two distinct dynamical systems. → Synchronization, de-synchronization and instantaneous synchronization. → A controlled pendulum synchronizing with the Duffing oscillator. → Synchronization invariant set. → Synchronization parameter map. - Abstract: In this paper, synchronization dynamics of two different dynamical systems is investigated through the theory of discontinuous dynamical systems. The necessary and sufficient conditions for the synchronization, de-synchronization and instantaneous synchronization (penetration or grazing) are presented. Using such a synchronization theory, the synchronization of a controlled pendulum with the Duffing oscillator is systematically discussed as a sampled problem, and the corresponding analytical conditions for the synchronization are presented. The synchronization parameter study is carried out for a better understanding of synchronization characteristics of the controlled pendulum and the Duffing oscillator. Finally, the partial and full synchronizations of the controlled pendulum with periodic and chaotic motions are presented to illustrate the analytical conditions. The synchronization of the Duffing oscillator and pendulum are investigated in order to show the usefulness and efficiency of the methodology in this paper. The synchronization invariant domain is obtained. The technique presented in this paper should have a wide spectrum of applications in engineering. For example, this technique can be applied to the maneuvering target tracking, and the others.
Geometric theory of discrete nonautonomous dynamical systems
Pötzsche, Christian
2010-01-01
Nonautonomous dynamical systems provide a mathematical framework for temporally changing phenomena, where the law of evolution varies in time due to seasonal, modulation, controlling or even random effects. Our goal is to provide an approach to the corresponding geometric theory of nonautonomous discrete dynamical systems in infinite-dimensional spaces by virtue of 2-parameter semigroups (processes). These dynamical systems are generated by implicit difference equations, which explicitly depend on time. Compactness and dissipativity conditions are provided for such problems in order to have attractors using the natural concept of pullback convergence. Concerning a necessary linear theory, our hyperbolicity concept is based on exponential dichotomies and splittings. This concept is in turn used to construct nonautonomous invariant manifolds, so-called fiber bundles, and deduce linearization theorems. The results are illustrated using temporal and full discretizations of evolutionary differential equations.
Algebraic Structure of Dynamical Systems
2017-05-22
dynamical system is a function based upon a finite window size of a sequence. Suppose we have a function ϕ which we know is a symmetry of a system (X...this finite window , we can determine what ϕ(x)i is. Example 4.3. Let (X, T ) be a symbolic dynamical system . Let x = . . . 011011110001 . . .. Suppose...the centralizer of any dynamical system is a group with the operation of composition. Given a dynamical system (X, T ) acted on by Z we say that the
Nonequilibrium phase transition in a system with chaotic dynamics. The ABCDE model
Friedrich, R.; Haken, H.
1992-04-01
For the ABCDE model, a low-dimensional dynamical system devised to study the generation of magnetic fields by convective fluid motions, we examine a nonequilibrium phase transition in a system with chaotic dynamics.
Dynamic Modeling of ALS Systems
Jones, Harry
2002-01-01
The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.
Sedlmayr, N.; Jaeger, P.; Maiti, M.; Sirker, J.
2018-02-01
We study the Loschmidt echo for quenches in open one-dimensional lattice models with symmetry protected topological phases. For quenches where dynamical quantum phase transitions do occur we find that cusps in the bulk return rate at critical times tc are associated with sudden changes in the boundary contribution. For our main example, the Su-Schrieffer-Heeger model, we show that these sudden changes are related to the periodical appearance of two eigenvalues close to zero in the dynamical Loschmidt matrix. We demonstrate, furthermore, that the structure of the Loschmidt spectrum is linked to the periodic creation of long-range entanglement between the edges of the system.
Chaos for Discrete Dynamical System
Directory of Open Access Journals (Sweden)
Lidong Wang
2013-01-01
Full Text Available We prove that a dynamical system is chaotic in the sense of Martelli and Wiggins, when it is a transitive distributively chaotic in a sequence. Then, we give a sufficient condition for the dynamical system to be chaotic in the strong sense of Li-Yorke. We also prove that a dynamical system is distributively chaotic in a sequence, when it is chaotic in the strong sense of Li-Yorke.
Rhythmic dynamics and synchronization via dimensionality reduction: application to human gait.
Directory of Open Access Journals (Sweden)
Jie Zhang
Full Text Available Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and ubiquity of noise in such non-strictly periodic signals pose great challenges to current methodologies. To this end, we exploit the state-of-the-art technology in pattern recognition and, specifically, dimensionality reduction techniques, and propose to reconstruct and characterize the dynamics accurately on the cycle scale of the signal. This is achieved by deriving a low-dimensional representation of the cycles through global optimization, which effectively preserves the topology of the cycles that are embedded in a high-dimensional Euclidian space. Our approach demonstrates a clear advantage in capturing the intrinsic dynamics and probing the subtle synchronization patterns from uni/bivariate oscillatory signals over traditional methods. Application to human gait data for healthy subjects and diabetics reveals a significant difference in the dynamics of ankle movements and ankle-knee coordination, but not in knee movements. These results indicate that the impaired sensory feedback from the feet due to diabetes does not influence the knee movement in general, and that normal human walking is not critically dependent on the feedback from the peripheral nervous system.
Rhythmic dynamics and synchronization via dimensionality reduction: application to human gait.
Zhang, Jie; Zhang, Kai; Feng, Jianfeng; Small, Michael
2010-12-16
Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and ubiquity of noise in such non-strictly periodic signals pose great challenges to current methodologies. To this end, we exploit the state-of-the-art technology in pattern recognition and, specifically, dimensionality reduction techniques, and propose to reconstruct and characterize the dynamics accurately on the cycle scale of the signal. This is achieved by deriving a low-dimensional representation of the cycles through global optimization, which effectively preserves the topology of the cycles that are embedded in a high-dimensional Euclidian space. Our approach demonstrates a clear advantage in capturing the intrinsic dynamics and probing the subtle synchronization patterns from uni/bivariate oscillatory signals over traditional methods. Application to human gait data for healthy subjects and diabetics reveals a significant difference in the dynamics of ankle movements and ankle-knee coordination, but not in knee movements. These results indicate that the impaired sensory feedback from the feet due to diabetes does not influence the knee movement in general, and that normal human walking is not critically dependent on the feedback from the peripheral nervous system.
Quantum quenches and thermalization in one-dimensional systems
Rigol, Marcos
2010-03-01
We use quantum quenches to study the dynamics and thermalization of hardcore bosons and fermions in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown of thermalization as one approaches an integrable point. This is found to be a smooth process in which the predictions of standard statistical mechanics continuously worsen as the system moves toward integrability. We establish a direct connection between the presence or absence of thermalization and the validity or failure of the eigenstate thermalization hypothesis, respectively.ReferencesM. Rigol, Phys. Rev. Lett. 103, 100403 (2009); Phys. Rev. A 80, 053607 (2009).
Breakdown of thermalization in finite one-dimensional systems.
Rigol, Marcos
2009-09-04
We use quantum quenches to study the dynamics and thermalization of hard core bosons in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown of thermalization as one approaches an integrable point. This is found to be a smooth process in which the predictions of standard statistical mechanics continuously worsen as the system moves toward integrability. We establish a direct connection between the presence or absence of thermalization and the validity or failure of the eigenstate thermalization hypothesis, respectively.
Self-diffusion in monodisperse three-dimensional magnetic fluids by molecular dynamics simulations
International Nuclear Information System (INIS)
Dobroserdova, A.B.; Kantorovich, S.S.
2017-01-01
In the present work we study the self-diffusion behaviour in the three-dimensional monodisperse magnetic fluids using the Molecular Dynamics Simulation and Density Functional Theory. The peculiarity of computer simulation is to study two different systems: dipolar and soft sphere ones. In the theoretical method, it is important to choose the approximation for the main structures, which are chains. We compare the theoretical results and the computer simulation data for the self-diffusion coefficient as a function of the particle volume fraction and magnetic dipole-dipole interaction parameter and find the qualitative and quantitative agreement to be good. - Highlights: • The paper deals with the study of the self-diffusion in monodisperse three-dimensional magnetic fluids. • The theoretical approach contains the free energy density functional minimization. • Computer simulations are performed by the molecular dynamics method. • We have a good qualitative and quantitative agreement between the theoretical results and computer simulation data.
Self-diffusion in monodisperse three-dimensional magnetic fluids by molecular dynamics simulations
Energy Technology Data Exchange (ETDEWEB)
Dobroserdova, A.B. [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); Kantorovich, S.S., E-mail: alla.dobroserdova@urfu.ru [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); University of Vienna, Sensengasse 8, Vienna (Austria)
2017-06-01
In the present work we study the self-diffusion behaviour in the three-dimensional monodisperse magnetic fluids using the Molecular Dynamics Simulation and Density Functional Theory. The peculiarity of computer simulation is to study two different systems: dipolar and soft sphere ones. In the theoretical method, it is important to choose the approximation for the main structures, which are chains. We compare the theoretical results and the computer simulation data for the self-diffusion coefficient as a function of the particle volume fraction and magnetic dipole-dipole interaction parameter and find the qualitative and quantitative agreement to be good. - Highlights: • The paper deals with the study of the self-diffusion in monodisperse three-dimensional magnetic fluids. • The theoretical approach contains the free energy density functional minimization. • Computer simulations are performed by the molecular dynamics method. • We have a good qualitative and quantitative agreement between the theoretical results and computer simulation data.
Statistical mechanical analysis of (1 + infinity) dimensional disordered systems
Skantzos, N S
2001-01-01
Valuable insight into the theory of disordered systems and spin-glasses has been offered by two classes of exactly solvable models: one-dimensional models and mean-field (infinite-range) ones, which, each carry their own specific techniques and restrictions. Both classes of models are now considered as 'exactly solvable' in the sense that in the thermodynamic limit the partition sum can been carried out analytically and the average over the disorder can be performed using methods which are well understood. In this thesis I study equilibrium properties of spin systems with a combination of one-dimensional short- and infinite-range interactions. I find that such systems, under either synchronous or asynchronous spin dynamics, and even in the absence of disorder, lead to phase diagrams with first-order transitions and regions with a multiple number of locally stable states. I then proceed to the study of recurrent neural network models with (1+infinity)-dimensional interactions, and find that the competing short...
3-dimensional forces and molecular dynamics of live cells
Hur, Sung Sik; Li, Yi-Shuan; Park, Joon Seok; Hu, Ying-Li; Chien, Shu
2010-08-01
The forces exerted by an adherent cell on a substrate were studied previously only in the two-dimensions (2D) tangential to the substrate surface. We used a novel technique to measure the three-dimensional (3D) stresses exerted by live bovine aortic endothelial cells (BAECs) on polyacrylamide deformable substrate, with particular emphasis on the 3D forces of focal adhesions. On 3D images acquired by confocal microscopy, displacements were determined with imageprocessing programs, and stresses in tangential (XY) and normal (Z) directions were computed by finite element method (FEM). BAECs generated stress in normal direction (Tz) with an order of magnitude comparable to that in tangential direction (Txy). Tz is upward at the cell edge and downward under the nucleus, changing continuously with a sign reversal between cell edge and nucleus edge. With the use of green fluorescent protein (GFP) labeled paxillin, the dynamics of this intracellular molecule were studied concurrently with the measurement of 3D forces. In the dynamic region, including the new lamellapodium forming region in the front and the retracting region in the rear, the tangential forces (Fxy) are correlated with the size of the focal adhesions (FAs) much more strongly than those in the stable region under the nucleus. In the dynamic region, normal force (Fz) was upward and positively correlated with FA size, while Fz in the stable region was downward and negatively correlated with FA size. These findings show the influence of the size of FAs on the 3D forces they exert on the substrate. This technique can be applied to study any adherent type of live cells to assess their biomechanical dynamics in conjunction with biochemical and functional activities, thus elucidating cellular functions in health and disease.
Acosta, A M; Kirsch, R F; Perreault, E J
2000-10-30
Experimental techniques for estimating the two-dimensional dynamic stiffness of the human arm over a wide range of conditions have been developed. A robotic manipulator has been developed to create loads against which subjects perform various tasks and also to impose perturbations onto the endpoint of the arm to allow estimation of its mechanical properties. The manipulator can produce static endpoint forces exceeding 220 N in any direction in its plane of motion, and this plane can be vertically translated and tilted over wide ranges to study arm dynamic stiffness in many functionally relevant planes. It can impose stochastic position and force perturbations whose bandwidth exceeds that of the arm. These random perturbations avoid undesirable volitional reactions and allow the efficient estimation of stiffness dynamics using experimental trials of short duration. The ability of this manipulator to characterize inertial-viscoelastic systems was tested using several two-dimensional physical systems whose properties were independently characterized. The endpoint dynamic stiffness properties of a human arm were estimated as an example of the use of the manipulator in studying upper limb mechanical properties. The system properties characterized by these methods will be useful in probing normal neural arm control strategies and in developing rehabilitation interventions to improve arm movements in disabled individuals.
Directory of Open Access Journals (Sweden)
Amir Reza Moadeli
2016-01-01
Full Text Available In this paper, the system control design problem twin rotors helicopters Unmanned Aerial Vehicles (UAV in three dimensional space Without uncertainty based on the dynamic adaptive control is studied. the adaptive Dynamic surface control approach complexity explosion problem in non-linear control step back or backstepping method [45] using the First-order filters removed. The first helicopter dynamic equations and functions are examined. Then, the Dynamic surface control techniques by compare non-linear control technique back stepping [45] is checked and the system is simulation by both techniques adaptive Dynamic surface control and nonlinear control back stepping method. The proposed adaptive dynamics surface nonlinear control method approach is able to guarantees that all the signals in the closed-loop system are asymptotically stable for all initial conditions and you can also choose appropriate design parameters of the system output converges to a small neighborhood of origin ensured . Finally, simulation results are presented, showing the effectiveness of control methods are given.
Dynamics of quasi-stable dissipative systems
Chueshov, Igor
2015-01-01
This book is devoted to background material and recently developed mathematical methods in the study of infinite-dimensional dissipative systems. The theory of such systems is motivated by the long-term goal to establish rigorous mathematical models for turbulent and chaotic phenomena. The aim here is to offer general methods and abstract results pertaining to fundamental dynamical systems properties related to dissipative long-time behavior. The book systematically presents, develops and uses the quasi-stability method while substantially extending it by including for consideration new classes of models and PDE systems arising in Continuum Mechanics. The book can be used as a textbook in dissipative dynamics at the graduate level. Igor Chueshov is a Professor of Mathematics at Karazin Kharkov National University in Kharkov, Ukraine.
Management of complex dynamical systems
MacKay, R. S.
2018-02-01
Complex dynamical systems are systems with many interdependent components which evolve in time. One might wish to control their trajectories, but a more practical alternative is to control just their statistical behaviour. In many contexts this would be both sufficient and a more realistic goal, e.g. climate and socio-economic systems. I refer to it as ‘management’ of complex dynamical systems. In this paper, some mathematics for management of complex dynamical systems is developed in the weakly dependent regime, and questions are posed for the strongly dependent regime.
International Nuclear Information System (INIS)
Johnson, H.W.; Vaish, A.K.; Porter, F.L.; McGeorge, R.
1975-01-01
A modelling technique which can be used to obtain the dynamic response of a floating nuclear plant (FNP) moored in an artificial basin is presented. Hydrodynamic effects of the seawater in the basin have a significant impact on the response of the FNP and must be included. A three dimensional model of the platform and mooring system (using beam elements) is used, with the hydrodynamic effects represented by added mass and damping. For an essentially square plant in close proximity to the site structures, the three dimensional nature of the basin must be considered in evaluating the added mass and damping. A method for estimating these effects from planer finite element analyses is developed. The accuracy of the planar finite element model in obtaining two-dimensional added mass and damping is shown through comparison with existing the documented results. In addition, a comparison is shown for open ocean added mass and damping with a three-dimensional solution using velocity potential functions. It is concluded that the overall technique results in a reasonable and conservative calculation of the dynamic response of the floating nuclear plant. (orig./HP) [de
Configuration memory in patchwork dynamics for low-dimensional spin glasses
Yang, Jie; Middleton, A. Alan
2017-12-01
A patchwork method is used to study the dynamics of loss and recovery of an initial configuration in spin glass models in dimensions d =1 and d =2 . The patchwork heuristic is used to accelerate the dynamics to investigate how models might reproduce the remarkable memory effects seen in experiment. Starting from a ground-state configuration computed for one choice of nearest-neighbor spin couplings, the sample is aged up to a given scale under new random couplings, leading to the partial erasure of the original ground state. The couplings are then restored to the original choice and patchwork coarsening is again applied, in order to assess the recovery of the original state. Eventual recovery of the original ground state upon coarsening is seen in two-dimensional Ising spin glasses and one-dimensional clock models, while one-dimensional Ising spin systems neither lose nor gain overlap with the ground state during the recovery stage. The recovery for the two-dimensional Ising spin glasses suggests scaling relations that lead to a recovery length scale that grows as a power of the aging length scale.
Dimensionality reduction and dynamical filtering: Stimulated Brillouin scattering in optical fibers.
Setra, Rafael G; Arroyo-Almanza, Diana A; Ni, Zetian; Murphy, Thomas E; Roy, Rajarshi
2015-08-01
Stimulated Brillouin scattering (SBS) is a noise-driven nonlinear interaction between acoustical and optical waves. In optical fibers, SBS can be observed at relatively low optical powers and can severely limit signal transmission. Although SBS is initiated by high dimensional noise, it also exhibits many of the hallmarks of a complex nonlinear dynamical system. We report here a comprehensive experimental and numerical study of the fluctuations in the reflected Stokes wave produced by SBS in optical fibers. Using time series analysis, we demonstrate a reduction of dimensionality and dynamical filtering of the Stokes wave. We begin with a careful comparison of the measured average transmitted and reflected intensities from below the SBS threshold to saturation of the transmitted power. Initially the power spectra and correlation functions of the time series of the reflected wave fluctuations at the SBS threshold and above are measured and simulated. Much greater dynamical insight is provided when we study the scaling behavior of the intensity fluctuations using Hurst exponents and detrended fluctuation analysis for time scales extending over six orders of magnitude. At the highest input powers, we notice the emergence of three distinct dynamical scaling regimes: persistent, Brownian, and antipersistent. Next, we explore the Hilbert phase fluctuations of the intensity time series and amplitude-phase coupling. Finally, time-delay embedding techniques reveal a gradual reduction in dimensionality of the spatiotemporal dynamics as the laser input is increased toward saturation of the transmitted power. Through all of these techniques, we find a transition from noisier to smoother dynamics with increasing input power. We find excellent agreement between our experimental measurements and simulations.
Dimensionality reduction and dynamical filtering: Stimulated Brillouin scattering in optical fibers
Setra, Rafael G.; Arroyo-Almanza, Diana A.; Ni, Zetian; Murphy, Thomas E.; Roy, Rajarshi
2015-08-01
Stimulated Brillouin scattering (SBS) is a noise-driven nonlinear interaction between acoustical and optical waves. In optical fibers, SBS can be observed at relatively low optical powers and can severely limit signal transmission. Although SBS is initiated by high dimensional noise, it also exhibits many of the hallmarks of a complex nonlinear dynamical system. We report here a comprehensive experimental and numerical study of the fluctuations in the reflected Stokes wave produced by SBS in optical fibers. Using time series analysis, we demonstrate a reduction of dimensionality and dynamical filtering of the Stokes wave. We begin with a careful comparison of the measured average transmitted and reflected intensities from below the SBS threshold to saturation of the transmitted power. Initially the power spectra and correlation functions of the time series of the reflected wave fluctuations at the SBS threshold and above are measured and simulated. Much greater dynamical insight is provided when we study the scaling behavior of the intensity fluctuations using Hurst exponents and detrended fluctuation analysis for time scales extending over six orders of magnitude. At the highest input powers, we notice the emergence of three distinct dynamical scaling regimes: persistent, Brownian, and antipersistent. Next, we explore the Hilbert phase fluctuations of the intensity time series and amplitude-phase coupling. Finally, time-delay embedding techniques reveal a gradual reduction in dimensionality of the spatiotemporal dynamics as the laser input is increased toward saturation of the transmitted power. Through all of these techniques, we find a transition from noisier to smoother dynamics with increasing input power. We find excellent agreement between our experimental measurements and simulations.
Controlling Uncertain Dynamical Systems
Indian Academy of Sciences (India)
Author Affiliations. N Ananthkrishnan1 Rashi Bansal2. Head, CAE Analysis & Design Zeus Numerix Pvt Ltd. M-03, SINE, IIT Bombay Powai Mumbai 400076, India. MTech (Aerospace Engineering) with specialization in Dynamics & Control from IIT Bombay.
Dynamical properties of unconventional magnetic systems
International Nuclear Information System (INIS)
Helgesen, G.
1997-05-01
The Advanced Study Institute addressed the current experimental and theoretical knowledge of the dynamical properties of unconventional magnetic systems including low-dimensional and mesoscopic magnetism, unconventional ground state, quantum magnets and soft matter. The main approach in this Advanced Study Institute was to obtain basic understanding of co-operative phenomena, fluctuations and excitations in the wide range unconventional magnetic systems now being fabricated or envisioned. The report contains abstracts for lectures, invited seminars and posters, together with a list of the 95 participants from 24 countries with e-mail addresses
Epidemic Dynamics in Open Quantum Spin Systems
Pérez-Espigares, Carlos; Marcuzzi, Matteo; Gutiérrez, Ricardo; Lesanovsky, Igor
2017-10-01
We explore the nonequilibrium evolution and stationary states of an open many-body system that displays epidemic spreading dynamics in a classical and a quantum regime. Our study is motivated by recent experiments conducted in strongly interacting gases of highly excited Rydberg atoms where the facilitated excitation of Rydberg states competes with radiative decay. These systems approximately implement open quantum versions of models for population dynamics or disease spreading where species can be in a healthy, infected or immune state. We show that in a two-dimensional lattice, depending on the dominance of either classical or quantum effects, the system may display a different kind of nonequilibrium phase transition. We moreover discuss the observability of our findings in laser driven Rydberg gases with particular focus on the role of long-range interactions.
Ergodic theory and dynamical systems
Coudène, Yves
2016-01-01
This textbook is a self-contained and easy-to-read introduction to ergodic theory and the theory of dynamical systems, with a particular emphasis on chaotic dynamics. This book contains a broad selection of topics and explores the fundamental ideas of the subject. Starting with basic notions such as ergodicity, mixing, and isomorphisms of dynamical systems, the book then focuses on several chaotic transformations with hyperbolic dynamics, before moving on to topics such as entropy, information theory, ergodic decomposition and measurable partitions. Detailed explanations are accompanied by numerous examples, including interval maps, Bernoulli shifts, toral endomorphisms, geodesic flow on negatively curved manifolds, Morse-Smale systems, rational maps on the Riemann sphere and strange attractors. Ergodic Theory and Dynamical Systems will appeal to graduate students as well as researchers looking for an introduction to the subject. While gentle on the beginning student, the book also contains a number of commen...
Nonlinear PDEs a dynamical systems approach
Schneider, Guido
2017-01-01
This is an introductory textbook about nonlinear dynamics of PDEs, with a focus on problems over unbounded domains and modulation equations. The presentation is example-oriented, and new mathematical tools are developed step by step, giving insight into some important classes of nonlinear PDEs and nonlinear dynamics phenomena which may occur in PDEs. The book consists of four parts. Parts I and II are introductions to finite- and infinite-dimensional dynamics defined by ODEs and by PDEs over bounded domains, respectively, including the basics of bifurcation and attractor theory. Part III introduces PDEs on the real line, including the Korteweg-de Vries equation, the Nonlinear Schrödinger equation and the Ginzburg-Landau equation. These examples often occur as simplest possible models, namely as amplitude or modulation equations, for some real world phenomena such as nonlinear waves and pattern formation. Part IV explores in more detail the connections between such complicated physical systems and the reduced...
Quantum correlation of high dimensional system in a dephasing environment
Ji, Yinghua; Ke, Qiang; Hu, Juju
2018-05-01
For a high dimensional spin-S system embedded in a dephasing environment, we theoretically analyze the time evolutions of quantum correlation and entanglement via Frobenius norm and negativity. The quantum correlation dynamics can be considered as a function of the decoherence parameters, including the ratio between the system oscillator frequency ω0 and the reservoir cutoff frequency ωc , and the different environment temperature. It is shown that the quantum correlation can not only measure nonclassical correlation of the considered system, but also perform a better robustness against the dissipation. In addition, the decoherence presents the non-Markovian features and the quantum correlation freeze phenomenon. The former is much weaker than that in the sub-Ohmic or Ohmic thermal reservoir environment.
Dynamical systems in classical mechanics
Kozlov, V V
1995-01-01
This book shows that the phenomenon of integrability is related not only to Hamiltonian systems, but also to a wider variety of systems having invariant measures that often arise in nonholonomic mechanics. Each paper presents unique ideas and original approaches to various mathematical problems related to integrability, stability, and chaos in classical dynamics. Topics include… the inverse Lyapunov theorem on stability of equilibria geometrical aspects of Hamiltonian mechanics from a hydrodynamic perspective current unsolved problems in the dynamical systems approach to classical mechanics
Reasoning about Dynamic Normative Systems
Knobbout, Max; Dastani, Mehdi; Meyer, John-Jules Charles
2014-01-01
The use of normative systems is widely accepted as an effective approach to control and regulate the behaviour of agents in multiagent systems. When norms are added to a normative system, the behaviour of such a system changes. As of yet, there is no clear formal methodology to model the dynamics of
Approximate Dynamic Programming Based on High Dimensional Model Representation
Czech Academy of Sciences Publication Activity Database
Pištěk, Miroslav
2013-01-01
Roč. 49, č. 5 (2013), s. 720-737 ISSN 0023-5954 R&D Projects: GA ČR(CZ) GAP102/11/0437 Institutional support: RVO:67985556 Keywords : approximate dynamic programming * Bellman equation * approximate HDMR minimization * trust region problem Subject RIV: BC - Control Systems Theory Impact factor: 0.563, year: 2013 http:// library .utia.cas.cz/separaty/2013/AS/pistek-0399560.pdf
Darnell, Malin; Ulvestad, Maria; Ellis, Ewa; Weidolf, Lars; Andersson, Tommy B
2012-10-01
Major human specific metabolites, not detected during in vivo and in vitro preclinical studies, may cause unexpected drug interactions and toxicity in human and delays in clinical programs. Thus, reliable preclinical tools for the detection of major human metabolites are of high importance. The aim of this study was to compare major drug metabolic pathways in HepaRG cells, a human hepatoma cell line, to fresh human hepatocytes, cryopreserved human hepatocytes, and human in vivo data. Furthermore, the maintenance of cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) activities in a dynamic three-dimensional (3D) bioreactor were evaluated over time by using HepaRG cells and human hepatocytes. (14)C-diclofenac and a candidate from AstraZeneca's drug development program, (14)C-AZD6610, which are metabolized by P450 and UGT in vivo, were used as model substrates. The proportion of relevant biotransformation pathways of the investigated drug was clearly different in the various cell systems. The hydroxylation route was favored in primary human hepatocytes, whereas the glucuronidation route was favored in HepaRG cells. The human in vivo metabolite profile of AZD6610 was best represented by human hepatocytes, whereas all major diclofenac metabolites were detected in HepaRG cells. Moreover, the metabolite profiles in cryopreserved and fresh human hepatocytes were essentially the same. The liver bioreactor using both fresh human hepatocytes and HepaRG cells retained biotransformation capacity over 1 week. Thus, the incubation time can be increased from a few hours in suspension to several days in 3D cultures, which opens up for detection of metabolites from slowly metabolized drugs.
Transport in low-dimensional mesoscopic systems
Energy Technology Data Exchange (ETDEWEB)
Syzranov, Sergey
2011-05-05
The work is devoted to the physics of graphene-based optoelectronics and arrays of Josephson junctions. The first part deals with transport in a graphene p-n junction irradiated by an electromagnetic field. The photocurrent in such device is calculated analytically and compared to those observed in the recent experiments on graphene photodetectors. It is shown that in a clean effectively one-dimensional junction the photocurrent oscillates as a function of gate voltages due to the interference between electron paths accompanied by the resonant photon absorption. The second part of the thesis is devoted to the construction of a Drude-like theory for the transport of Cooper pairs in weakly disordered Josephson networks and to finding the conductivity and the characteristic temperature of the commencement of strong localization. Also, it is shown that the low-temperature superconductor-insulator transition is necessarily of the first order in all 3D and in most 2D systems.
Permutation Complexity in Dynamical Systems
Amigo, Jose
2010-01-01
The study of permutation complexity can be envisioned as a new kind of symbolic dynamics whose basic blocks are ordinal patterns, that is, permutations defined by the order relations among points in the orbits of dynamical systems. Since its inception in 2002 the concept of permutation entropy has sparked a new branch of research in particular regarding the time series analysis of dynamical systems that capitalizes on the order structure of the state space. Indeed, on one hand ordinal patterns and periodic points are closely related, yet ordinal patterns are amenable to numerical methods, while periodicity is not. Another interesting feature is that since it can be shown that random (unconstrained) dynamics has no forbidden patterns with probability one, their existence can be used as a fingerprint to identify any deterministic origin of orbit generation. This book is primarily addressed to researchers working in the field of nonlinear dynamics and complex systems, yet will also be suitable for graduate stude...
Q-deformed systems and constrained dynamics
International Nuclear Information System (INIS)
Shabanov, S.V.
1993-01-01
It is shown that quantum theories of the q-deformed harmonic oscillator and one-dimensional free q-particle (a free particle on the 'quantum' line) can be obtained by the canonical quantization of classical Hamiltonian systems with commutative phase-space variables and a non-trivial symplectic structure. In the framework of this approach, classical dynamics of a particle on the q-line coincides with the one of a free particle with friction. It is argued that q-deformed systems can be treated as ordinary mechanical systems with the second-class constraints. In particular, second-class constrained systems corresponding to the q-oscillator and q-particle are given. A possibility of formulating q-deformed systems via gauge theories (first-class constrained systems) is briefly discussed. (orig.)
Three dimensional characterization and archiving system
International Nuclear Information System (INIS)
Sebastian, R.L.; Clark, R.; Gallman, P.
1996-01-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D and D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D and D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. The 3D-ICAS system robotically conveys a multisensor probe near the surfaces to be inspected. The sensor position and orientation are monitored and controlled using coherent laser radar (CLR) tracking. The CLR also provides 3D facility maps which establish a 3D world view within which the robotic sensor system can operate
Critical phenomena in quasi-two-dimensional vibrated granular systems.
Guzmán, Marcelo; Soto, Rodrigo
2018-01-01
The critical phenomena associated to the liquid-to-solid transition of quasi-two-dimensional vibrated granular systems is studied using molecular dynamics simulations of the inelastic hard sphere model. The critical properties are associated to the fourfold bond-orientational order parameter χ_{4}, which measures the level of square crystallization of the system. Previous experimental results have shown that the transition of χ_{4}, when varying the vibration amplitude, can be either discontinuous or continuous, for two different values of the height of the box. Exploring the amplitude-height phase space, a transition line is found, which can be either discontinuous or continuous, merging at a tricritical point and the continuous branch ends in an upper critical point. In the continuous transition branch, the critical properties are studied. The exponent associated to the amplitude of the order parameter is β=1/2, for various system sizes, in complete agreement with the experimental results. However, the fluctuations of χ_{4} do not show any critical behavior, probably due to crossover effects by the close presence of the tricritical point. Finally, in quasi-one-dimensional systems, the transition is only discontinuous, limited by one critical point, indicating that two is the lower dimension for having a tricritical point.
Two-dimensional nuclear magnetic resonance of quadrupolar systems
Energy Technology Data Exchange (ETDEWEB)
Wang, Shuanhu [Univ. of California, Berkeley, CA (United States)
1997-09-01
This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combining the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.
Lectures on chaotic dynamical systems
Afraimovich, Valentin
2002-01-01
This book is devoted to chaotic nonlinear dynamics. It presents a consistent, up-to-date introduction to the field of strange attractors, hyperbolic repellers, and nonlocal bifurcations. The authors keep the highest possible level of "physical" intuition while staying mathematically rigorous. In addition, they explain a variety of important nonstandard algorithms and problems involving the computation of chaotic dynamics. The book will help readers who are not familiar with nonlinear dynamics to understand and appreciate sophisticated modern dynamical systems and chaos. Intended for courses in either mathematics, physics, or engineering, prerequisites are calculus, differential equations, and functional analysis.
Dynamic Ocean Track System Plus -
Department of Transportation — Dynamic Ocean Track System Plus (DOTS Plus) is a planning tool implemented at the ZOA, ZAN, and ZNY ARTCCs. It is utilized by Traffic Management Unit (TMU) personnel...
Approaches to determining the reliability of a multimodal three-dimensional dynamic signature
Directory of Open Access Journals (Sweden)
Yury E. Kozlov
2018-03-01
Full Text Available The market of modern mobile applications has increasingly strict requirements for the authentication system reliability. This article examines an authentication method using a multimodal three-dimensional dynamic signature (MTDS, that can be used both as a main and additional method of user authentication in mobile applications. It is based on the use of gesture in the air performed by two independent mobile devices as an identifier. The MTDS method has certain advantages over currently used biometric methods, including fingerprint authentication, face recognition and voice recognition. A multimodal three-dimensional dynamic signature allows quickly changing an authentication gesture, as well as concealing the authentication procedure using gestures that do not attract attention. Despite all its advantages, the MTDS method has certain limitations, the main one is building functionally dynamic complex (FDC skills required for accurate repeating an authentication gesture. To correctly create MTDS need to have a system for assessing the reliability of gestures. Approaches to the solution of this task are grouped in this article according to methods of their implementation. Two of the approaches can be implemented only with the use of a server as a centralized MTDS processing center and one approach can be implemented using smartphone's own computing resources. The final part of the article provides data of testing one of these methods on a template performing the MTDS authentication.
Dynamical systems in population biology
Zhao, Xiao-Qiang
2017-01-01
This research monograph provides an introduction to the theory of nonautonomous semiflows with applications to population dynamics. It develops dynamical system approaches to various evolutionary equations such as difference, ordinary, functional, and partial differential equations, and pays more attention to periodic and almost periodic phenomena. The presentation includes persistence theory, monotone dynamics, periodic and almost periodic semiflows, basic reproduction ratios, traveling waves, and global analysis of prototypical population models in ecology and epidemiology. Research mathematicians working with nonlinear dynamics, particularly those interested in applications to biology, will find this book useful. It may also be used as a textbook or as supplementary reading for a graduate special topics course on the theory and applications of dynamical systems. Dr. Xiao-Qiang Zhao is a University Research Professor at Memorial University of Newfoundland, Canada. His main research interests involve applied...
Computer simulation of phase separation and ordering processes in low-dimensional systems
DEFF Research Database (Denmark)
Mouritsen, O.G.; Shah, P.J.; Vitting Andersen, J.
1991-01-01
on the nature of the conservation laws in effect. Atomic and molecular overlayers on solid surfaces and weakly-coupled atomic layers of certain three-dimensional crystals constitute a particularly suitable class of systems for studying fundamental aspects of ordering dynamics and phase separation in two...... dimensions since these systems provide a richness of ordering symmetries and degeneracies as well as they obey different conservation laws. Specific systems dealt with include the chemisorption systems O/W(110) and O/W(112), and oxygen layers in the basal CuO-planes of high-T(c) superconductors of the YBa2Cu......An account is given of recent activity in the field of dynamics of phase separation and ordering processes in two-dimensional statistical mechanical models. The fundamental questions of the dynamics involve the form of the growth law, the value of the growth exponent, the dynamical scaling...
Unifying static and dynamic properties in three-dimensional quantum antiferromagnets
Scammell, H. D.; Kharkov, Y.; Qin, Yan Qi; Meng, Zi Yang; Normand, B.; Sushkov, O. P.
2017-11-01
Quantum Monte Carlo simulations offer an unbiased means to study the static and dynamic properties of quantum critical systems, while quantum field theory provides direct analytical results. We study three-dimensional, critical quantum antiferromagnets by performing a combined analysis using both quantum field theory calculations and quantum Monte Carlo data. Explicitly, we analyze the order parameter (staggered magnetization), Néel temperature, quasiparticle gaps, and the susceptibilities in the scalar and vector channels. We connect the two approaches by deriving descriptions of the quantum Monte Carlo observables in terms of the quasiparticle excitations of the field theory. The remarkable agreement not only unifies the description of the static and dynamic properties of the system but also constitutes a thorough test of perturbative O(3) quantum field theory and opens new avenues for the analytical guidance of detailed numerical studies.
Ali, Suzanne
2017-06-01
As a material is dynamically compressed, heterogeneities form, perturbations propagate, and fracture networks develop. Information about the deformation and fracture of materials under shock compression is typically obtained in one of two ways; either derived post-shock, (i.e. from recovery experiments), where the material is shocked and then the recovered sample is examined, or inferred from features in one-dimensional transiting wave profiles. The first provides very limited information with regards to the time scale of deformation mechanisms, and the second provides limited information with regards to spatial scales. Recently, a two-dimensional imaging velocimetry technique has been developed on Omega (OHRV 2D-VISAR system) to measure the velocity roughness of shock fronts. We have used this diagnostic to study the heterogenous deformation in the elastic-plastic regime in diamond as well the propagation of perturbations in GDP, beryllium, and high density carbon ablators, observing features that are difficult to identify in one-dimensional experiments, but important for fully understanding dynamic material response. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Three-dimensional dynamic response modeling of floating nuclear plants using finite element methods
International Nuclear Information System (INIS)
Johnson, H.W.; Vaish, A.K.; Porter, F.L.; McGeorge, R.
1976-01-01
A modelling technique which can be used to obtain the dynamic response of a floating nuclear plant (FNP) moored in an artificial basin is presented. Hydrodynamic effects of the seawater in the basin have a significant impact on the response of the FNP and must be included. A three-dimensional model of the platform and mooring system (using beam elements) is used, with the hydrodynamic effects represented by added mass and damping. For an essentially square plant in close proximity to the site structures, the three-dimensional nature of the basin must be considered in evaluating the added mass and damping. However, direct solutions for hydrodynamic effects with complex basin geometry are not, as yet, available. A method for estimating these effects from planar finite element analysis is developed. (Auth.)
Rogers, Colin; An, Hongli
2011-10-01
An elliptic vortex ansatz is introduced into a (2+1)-dimensional modulated Madelung hydrodynamic system involving a logarithmic quantum potential. An eight-dimensional nonlinear dynamical system results, which is shown to have an underlying integrable Hamiltonian structure of Ermakov-Ray-Reid type.
Three dimensional characterization and archiving system
International Nuclear Information System (INIS)
Sebastian, R.L.; Clark, R.; Gallman, P.
1995-01-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D ampersand D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D ampersand D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. Chemical analysis plays a vital role throughout the process of decontamination. Before clean-up operations can begin the site must be characterized with respect to the type and concentration of contaminants, and detailed site mapping must clarify areas of both high and low risk. During remediation activities chemical analysis provides a means to measure progress and to adjust clean-up strategy. Once the clean-up process has been completed the results of chemical analysis will verify that the site is in compliance with federal and local regulations
Three dimensional characterization and archiving system
Energy Technology Data Exchange (ETDEWEB)
Sebastian, R.L.; Clark, R.; Gallman, P. [and others
1995-12-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D&D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D&D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. Chemical analysis plays a vital role throughout the process of decontamination. Before clean-up operations can begin the site must be characterized with respect to the type and concentration of contaminants, and detailed site mapping must clarify areas of both high and low risk. During remediation activities chemical analysis provides a means to measure progress and to adjust clean-up strategy. Once the clean-up process has been completed the results of chemical analysis will verify that the site is in compliance with federal and local regulations.
Fully three-dimensional analysis of high-speed traintracksoil-structure dynamic interaction
Galvín, Pedro; Romero Ordoñez, Antonio; Domínguez Abascal, José
2010-01-01
In this paper, a general and fully three dimensional multi-body-finite element-boundary element model, formulated in the time domain to predict vibrations due to train passage at the vehicle, the track and the free field, is presented. The vehicle is modelled as a multi-body system and, therefore, the quasi-static and the dynamic excitation mechanisms due to train passage can be considered. The track is modelled using finite elements. The soil is considered as a homogeneous half-space by the ...
Energy Technology Data Exchange (ETDEWEB)
Weber, Carsten
2008-07-01
This work is focused on the optical dynamics of mesoscopic semiconductor heterostructures, using as prototypes zero-dimensional quantum dots and quantum cascade lasers which consist of quasitwo- dimensional quantum wells. Within a density matrix theory, a microscopic many-particle theory is applied to study scattering effects in these structures: the coupling to external as well as local fields, electron-phonon coupling, coupling to impurities, and Coulomb coupling. For both systems, the investigated effects are compared to experimentally observed results obtained during the past years. In quantum dots, the three-dimensional spatial confinement leads to the necessity to consider a quantum kinetic description of the dynamics, resulting in non-Markovian electron-phonon effects. This can be seen in the spectral phonon sidebands due to interaction with acoustic phonons as well as a damping of nonlinear Rabi oscillations which shows a nonmonotonous intensity and pulse duration dependence. An analysis of the inclusion of the self-interaction of the quantum dot shows that no dynamical local field terms appear for the simple two-level model. Considering local fields which have their origin in many quantum dots, consequences for a two-level quantum dot such as a zero-phonon line broadening and an increasing signal in photon echo experiments are found. For the use of quantum dots in an optical spin control scheme, it is found that the dephasing due to the electron-phonon interaction can be dominant in certain regimes. Furthermore, soliton and breather solutions are studied analytically in nonlinear quantum dot ensembles. Generalizing to quasi-two-dimensional structures, the intersubband dynamics of quantum cascade laser structures is investigated. A dynamical theory is considered in which the temporal evolution of the subband populations and the current density as well as the influence of scattering effects is studied. In the nonlinear regime, the scattering dependence and
ENSO dynamics in current climate models: an investigation using nonlinear dimensionality reduction
Directory of Open Access Journals (Sweden)
I. Ross
2008-04-01
Full Text Available Linear dimensionality reduction techniques, notably principal component analysis, are widely used in climate data analysis as a means to aid in the interpretation of datasets of high dimensionality. These linear methods may not be appropriate for the analysis of data arising from nonlinear processes occurring in the climate system. Numerous techniques for nonlinear dimensionality reduction have been developed recently that may provide a potentially useful tool for the identification of low-dimensional manifolds in climate data sets arising from nonlinear dynamics. Here, we apply Isomap, one such technique, to the study of El Niño/Southern Oscillation variability in tropical Pacific sea surface temperatures, comparing observational data with simulations from a number of current coupled atmosphere-ocean general circulation models. We use Isomap to examine El Niño variability in the different datasets and assess the suitability of the Isomap approach for climate data analysis. We conclude that, for the application presented here, analysis using Isomap does not provide additional information beyond that already provided by principal component analysis.
ENSO dynamics in current climate models: an investigation using nonlinear dimensionality reduction
Ross, I.; Valdes, P. J.; Wiggins, S.
2008-04-01
Linear dimensionality reduction techniques, notably principal component analysis, are widely used in climate data analysis as a means to aid in the interpretation of datasets of high dimensionality. These linear methods may not be appropriate for the analysis of data arising from nonlinear processes occurring in the climate system. Numerous techniques for nonlinear dimensionality reduction have been developed recently that may provide a potentially useful tool for the identification of low-dimensional manifolds in climate data sets arising from nonlinear dynamics. Here, we apply Isomap, one such technique, to the study of El Niño/Southern Oscillation variability in tropical Pacific sea surface temperatures, comparing observational data with simulations from a number of current coupled atmosphere-ocean general circulation models. We use Isomap to examine El Niño variability in the different datasets and assess the suitability of the Isomap approach for climate data analysis. We conclude that, for the application presented here, analysis using Isomap does not provide additional information beyond that already provided by principal component analysis.
Zubov, V. I.
Papers are presented on mathematical methods for the analysis of control systems for technical plants and manufacturing processes. Particular attention is given to the mechanics of controlled space flight, the design of automatic control systems, flexible automated complexes, control applications in biomedical research, and chemical technology for the production of new types of materials.
Self-supervised dynamical systems
International Nuclear Information System (INIS)
Zak, Michail
2004-01-01
A new type of dynamical systems which capture the interactions via information flows typical for active multi-agent systems is introduced. The mathematical formalism is based upon coupling the classical dynamical system (with random components caused by uncertainties in initial conditions as well as by Langevin forces) with the corresponding Liouville or the Fokker-Planck equations describing evolution of these uncertainties in terms of probability density. The coupling is implemented by information-based supervising forces which fundamentally change the patterns of probability evolution. It is demonstrated that the probability density can approach prescribed attractors while exhibiting such patterns as shock waves, solitons and chaos in probability space. Applications of these phenomena to information-based neural nets, expectation-based cooperation, self-programmed systems, control chaos using terminal attractors as well as to games with incomplete information, are addressed. A formal similarity between the mathematical structure of the introduced dynamical systems and quantum mechanics is discussed
Two-dimensional dynamics of elasto-inertial turbulence and its role in polymer drag reduction
Sid, S.; Terrapon, V. E.; Dubief, Y.
2018-02-01
The goal of the present study is threefold: (i) to demonstrate the two-dimensional nature of the elasto-inertial instability in elasto-inertial turbulence (EIT), (ii) to identify the role of the bidimensional instability in three-dimensional EIT flows, and (iii) to establish the role of the small elastic scales in the mechanism of self-sustained EIT. Direct numerical simulations of viscoelastic fluid flows are performed in both two- and three-dimensional straight periodic channels using the Peterlin finitely extensible nonlinear elastic model (FENE-P). The Reynolds number is set to Reτ=85 , which is subcritical for two-dimensional flows but beyond the transition for three-dimensional ones. The polymer properties selected correspond to those of typical dilute polymer solutions, and two moderate Weissenberg numbers, Wiτ=40 ,100 , are considered. The simulation results show that sustained turbulence can be observed in two-dimensional subcritical flows, confirming the existence of a bidimensional elasto-inertial instability. The same type of instability is also observed in three-dimensional simulations where both Newtonian and elasto-inertial turbulent structures coexist. Depending on the Wi number, one type of structure can dominate and drive the flow. For large Wi values, the elasto-inertial instability tends to prevail over the Newtonian turbulence. This statement is supported by (i) the absence of typical Newtonian near-wall vortices and (ii) strong similarities between two- and three-dimensional flows when considering larger Wi numbers. The role of small elastic scales is investigated by introducing global artificial diffusion (GAD) in the hyperbolic transport equation for polymers. The aim is to measure how the flow reacts when the smallest elastic scales are progressively filtered out. The study results show that the introduction of large polymer diffusion in the system strongly damps a significant part of the elastic scales that are necessary to feed
Nonlinear dynamics in biological systems
Carballido-Landeira, Jorge
2016-01-01
This book presents recent research results relating to applications of nonlinear dynamics, focusing specifically on four topics of wide interest: heart dynamics, DNA/RNA, cell mobility, and proteins. The book derives from the First BCAM Workshop on Nonlinear Dynamics in Biological Systems, held in June 2014 at the Basque Center of Applied Mathematics (BCAM). At this international meeting, researchers from different but complementary backgrounds, including molecular dynamics, physical chemistry, bio-informatics and biophysics, presented their most recent results and discussed the future direction of their studies using theoretical, mathematical modeling and experimental approaches. Such was the level of interest stimulated that the decision was taken to produce this publication, with the organizers of the event acting as editors. All of the contributing authors are researchers working on diverse biological problems that can be approached using nonlinear dynamics. The book will appeal especially to applied math...
Dynamically reconfigurable photovoltaic system
Okandan, Murat; Nielson, Gregory N.
2016-05-31
A PV system composed of sub-arrays, each having a group of PV cells that are electrically connected to each other. A power management circuit for each sub-array has a communications interface and serves to connect or disconnect the sub-array to a programmable power grid. The power grid has bus rows and bus columns. A bus management circuit is positioned at a respective junction of a bus column and a bus row and is programmable through its communication interface to connect or disconnect a power path in the grid. As a result, selected sub-arrays are connected by selected power paths to be in parallel so as to produce a low system voltage, and, alternately in series so as to produce a high system voltage that is greater than the low voltage by at least a factor of ten.
Structures of two-dimensional three-body systems
International Nuclear Information System (INIS)
Ruan, W.Y.; Liu, Y.Y.; Bao, C.G.
1996-01-01
Features of the structure of L = 0 states of a two-dimensional three-body model system have been investigated. Three types of permutation symmetry of the spatial part, namely symmetric, antisymmetric, and mixed, have been considered. A comparison has been made between the two-dimensional system and the corresponding three-dimensional one. The effect of symmetry on microscopic structures is emphasized. (author)
Nonnegative and Compartmental Dynamical Systems
Haddad, Wassim M; Hui, Qing
2010-01-01
This comprehensive book provides the first unified framework for stability and dissipativity analysis and control design for nonnegative and compartmental dynamical systems, which play a key role in a wide range of fields, including engineering, thermal sciences, biology, ecology, economics, genetics, chemistry, medicine, and sociology. Using the highest standards of exposition and rigor, the authors explain these systems and advance the state of the art in their analysis and active control design. Nonnegative and Compartmental Dynamical Systems presents the most complete treatment available o
Howard, Ronald A
2007-01-01
This book is an integrated work published in two volumes. The first volume treats the basic Markov process and its variants; the second, semi-Markov and decision processes. Its intent is to equip readers to formulate, analyze, and evaluate simple and advanced Markov models of systems, ranging from genetics and space engineering to marketing. More than a collection of techniques, it constitutes a guide to the consistent application of the fundamental principles of probability and linear system theory.Author Ronald A. Howard, Professor of Management Science and Engineering at Stanford University
Controlling dynamics in diatomic systems
Indian Academy of Sciences (India)
Keywords. Iterative method; optimal control theory; diatomic systems; quantum control. Abstract. Controlling molecular energetics using laser pulses is exemplified for nuclear motion in two different diatomic systems. The problem of finding the optimized field for maximizing a desired quantum dynamical target is formulated ...
NATO Advanced Study Institute on Hamiltonian Dynamical Systems and Applications
2008-01-01
Physical laws are for the most part expressed in terms of differential equations, and natural classes of these are in the form of conservation laws or of problems of the calculus of variations for an action functional. These problems can generally be posed as Hamiltonian systems, whether dynamical systems on finite dimensional phase space as in classical mechanics, or partial differential equations (PDE) which are naturally of infinitely many degrees of freedom. This volume is the collected and extended notes from the lectures on Hamiltonian dynamical systems and their applications that were given at the NATO Advanced Study Institute in Montreal in 2007. Many aspects of the modern theory of the subject were covered at this event, including low dimensional problems as well as the theory of Hamiltonian systems in infinite dimensional phase space; these are described in depth in this volume. Applications are also presented to several important areas of research, including problems in classical mechanics, continu...
Parametric Resonance in Dynamical Systems
Nijmeijer, Henk
2012-01-01
Parametric Resonance in Dynamical Systems discusses the phenomenon of parametric resonance and its occurrence in mechanical systems,vehicles, motorcycles, aircraft and marine craft, and micro-electro-mechanical systems. The contributors provide an introduction to the root causes of this phenomenon and its mathematical equivalent, the Mathieu-Hill equation. Also included is a discussion of how parametric resonance occurs on ships and offshore systems and its frequency in mechanical and electrical systems. This book also: Presents the theory and principles behind parametric resonance Provides a unique collection of the different fields where parametric resonance appears including ships and offshore structures, automotive vehicles and mechanical systems Discusses ways to combat, cope with and prevent parametric resonance including passive design measures and active control methods Parametric Resonance in Dynamical Systems is ideal for researchers and mechanical engineers working in application fields such as MEM...
Statistical mechanics of complex neural systems and high dimensional data
International Nuclear Information System (INIS)
Advani, Madhu; Lahiri, Subhaneil; Ganguli, Surya
2013-01-01
Recent experimental advances in neuroscience have opened new vistas into the immense complexity of neuronal networks. This proliferation of data challenges us on two parallel fronts. First, how can we form adequate theoretical frameworks for understanding how dynamical network processes cooperate across widely disparate spatiotemporal scales to solve important computational problems? Second, how can we extract meaningful models of neuronal systems from high dimensional datasets? To aid in these challenges, we give a pedagogical review of a collection of ideas and theoretical methods arising at the intersection of statistical physics, computer science and neurobiology. We introduce the interrelated replica and cavity methods, which originated in statistical physics as powerful ways to quantitatively analyze large highly heterogeneous systems of many interacting degrees of freedom. We also introduce the closely related notion of message passing in graphical models, which originated in computer science as a distributed algorithm capable of solving large inference and optimization problems involving many coupled variables. We then show how both the statistical physics and computer science perspectives can be applied in a wide diversity of contexts to problems arising in theoretical neuroscience and data analysis. Along the way we discuss spin glasses, learning theory, illusions of structure in noise, random matrices, dimensionality reduction and compressed sensing, all within the unified formalism of the replica method. Moreover, we review recent conceptual connections between message passing in graphical models, and neural computation and learning. Overall, these ideas illustrate how statistical physics and computer science might provide a lens through which we can uncover emergent computational functions buried deep within the dynamical complexities of neuronal networks. (paper)
Gu, Yejun; El-Awady, Jaafar A.
2018-03-01
We present a new framework to quantify the effect of hydrogen on dislocations using large scale three-dimensional (3D) discrete dislocation dynamics (DDD) simulations. In this model, the first order elastic interaction energy associated with the hydrogen-induced volume change is accounted for. The three-dimensional stress tensor induced by hydrogen concentration, which is in equilibrium with respect to the dislocation stress field, is derived using the Eshelby inclusion model, while the hydrogen bulk diffusion is treated as a continuum process. This newly developed framework is utilized to quantify the effect of different hydrogen concentrations on the dynamics of a glide dislocation in the absence of an applied stress field as well as on the spacing between dislocations in an array of parallel edge dislocations. A shielding effect is observed for materials having a large hydrogen diffusion coefficient, with the shield effect leading to the homogenization of the shrinkage process leading to the glide loop maintaining its circular shape, as well as resulting in a decrease in dislocation separation distances in the array of parallel edge dislocations. On the other hand, for materials having a small hydrogen diffusion coefficient, the high hydrogen concentrations around the edge characters of the dislocations act to pin them. Higher stresses are required to be able to unpin the dislocations from the hydrogen clouds surrounding them. Finally, this new framework can open the door for further large scale studies on the effect of hydrogen on the different aspects of dislocation-mediated plasticity in metals. With minor modifications of the current formulations, the framework can also be extended to account for general inclusion-induced stress field in discrete dislocation dynamics simulations.
Statistics of resonances in one-dimensional continuous systems
Indian Academy of Sciences (India)
pp. 565–572. Statistics of resonances in one-dimensional continuous systems. JOSHUA FEINBERG. Physics Department, University of Haifa at Oranim, Tivon 36006, Israel and ... dimensional continuous open system. The disordered .... due to this integration backwards, f(x, k) can only depend on values of V (y) with y>x.
Dynamic simulation of LMFBR systems
International Nuclear Information System (INIS)
Agrawal, A.K.; Khatib-Rahbar, M.
1980-01-01
This review article focuses on the dynamic analysis of liquid-metal-cooled fast breeder reactor systems in the context of protected transients. Following a brief discussion on various design and simulation approaches, a critical review of various models for in-reactor components, intermediate heat exchangers, heat transport systems and the steam generating system is presented. A brief discussion on choice of fuels as well as core and blanket system designs is also included. Numerical considerations for obtaining system-wide steady-state and transient solutions are discussed, and examples of various system transients are presented. Another area of major interest is verification of phenomenological models. Various steps involved in the code and model verification are briefly outlined. The review concludes by posing some further areas of interest in fast reactor dynamics and safety. (author)
Four-dimensional maps of the human somatosensory system.
Avanzini, Pietro; Abdollahi, Rouhollah O; Sartori, Ivana; Caruana, Fausto; Pelliccia, Veronica; Casaceli, Giuseppe; Mai, Roberto; Lo Russo, Giorgio; Rizzolatti, Giacomo; Orban, Guy A
2016-03-29
A fine-grained description of the spatiotemporal dynamics of human brain activity is a major goal of neuroscientific research. Limitations in spatial and temporal resolution of available noninvasive recording and imaging techniques have hindered so far the acquisition of precise, comprehensive four-dimensional maps of human neural activity. The present study combines anatomical and functional data from intracerebral recordings of nearly 100 patients, to generate highly resolved four-dimensional maps of human cortical processing of nonpainful somatosensory stimuli. These maps indicate that the human somatosensory system devoted to the hand encompasses a widespread network covering more than 10% of the cortical surface of both hemispheres. This network includes phasic components, centered on primary somatosensory cortex and neighboring motor, premotor, and inferior parietal regions, and tonic components, centered on opercular and insular areas, and involving human parietal rostroventral area and ventral medial-superior-temporal area. The technique described opens new avenues for investigating the neural basis of all levels of cortical processing in humans.
Directory of Open Access Journals (Sweden)
Balasubramanian Ram
1988-01-01
Full Text Available This paper suggests a method of formulating any nonlinear integer programming problem, with any number of constraints, as an equivalent single constraint problem, thus reducing the dimensionality of the associated dynamic programming problem.
Dynamic mode decomposition for compressive system identification
Bai, Zhe; Kaiser, Eurika; Proctor, Joshua L.; Kutz, J. Nathan; Brunton, Steven L.
2017-11-01
Dynamic mode decomposition has emerged as a leading technique to identify spatiotemporal coherent structures from high-dimensional data. In this work, we integrate and unify two recent innovations that extend DMD to systems with actuation and systems with heavily subsampled measurements. When combined, these methods yield a novel framework for compressive system identification, where it is possible to identify a low-order model from limited input-output data and reconstruct the associated full-state dynamic modes with compressed sensing, providing interpretability of the state of the reduced-order model. When full-state data is available, it is possible to dramatically accelerate downstream computations by first compressing the data. We demonstrate this unified framework on simulated data of fluid flow past a pitching airfoil, investigating the effects of sensor noise, different types of measurements (e.g., point sensors, Gaussian random projections, etc.), compression ratios, and different choices of actuation (e.g., localized, broadband, etc.). This example provides a challenging and realistic test-case for the proposed method, and results indicate that the dominant coherent structures and dynamics are well characterized even with heavily subsampled data.
Harnad, J.; Loutsenko, I.; Yermolayeva, O.
2005-11-01
Finite-dimensional reductions of the two-dimensional dispersionless Toda hierarchy constrained by the "string equation" are studied. These include solutions determined by polynomial, rational, or logarithmic functions, which are of interest in relation to the "Laplacian growth" or Hele-Shaw problem governing interface dynamics. The consistency of such reductions is proved, and the Hamiltonian structure of the reduced dynamics is derived. The Poisson structure of the rationally reduced dispersionless Toda hierarchies is also derived.
Applications of Nonlinear Dynamics Model and Design of Complex Systems
In, Visarath; Palacios, Antonio
2009-01-01
This edited book is aimed at interdisciplinary, device-oriented, applications of nonlinear science theory and methods in complex systems. In particular, applications directed to nonlinear phenomena with space and time characteristics. Examples include: complex networks of magnetic sensor systems, coupled nano-mechanical oscillators, nano-detectors, microscale devices, stochastic resonance in multi-dimensional chaotic systems, biosensors, and stochastic signal quantization. "applications of nonlinear dynamics: model and design of complex systems" brings together the work of scientists and engineers that are applying ideas and methods from nonlinear dynamics to design and fabricate complex systems.
Paganin, David M.; Beltran, Mario A.; Petersen, Timothy C.
2018-03-01
We obtain exact polynomial solutions for two-dimensional coherent complex scalar fields propagating through arbitrary aberrated shift-invariant linear imaging systems. These are used to model nodal-line dynamics of coherent fields output by such systems.
Dynamics of Variable Mass Systems
Eke, Fidelis O.
1998-01-01
This report presents the results of an investigation of the effects of mass loss on the attitude behavior of spinning bodies in flight. The principal goal is to determine whether there are circumstances under which the motion of variable mass systems can become unstable in the sense that their transverse angular velocities become unbounded. Obviously, results from a study of this kind would find immediate application in the aerospace field. The first part of this study features a complete and mathematically rigorous derivation of a set of equations that govern both the translational and rotational motions of general variable mass systems. The remainder of the study is then devoted to the application of the equations obtained to a systematic investigation of the effect of various mass loss scenarios on the dynamics of increasingly complex models of variable mass systems. It is found that mass loss can have a major impact on the dynamics of mechanical systems, including a possible change in the systems stability picture. Factors such as nozzle geometry, combustion chamber geometry, propellant's initial shape, size and relative mass, and propellant location can all have important influences on the system's dynamic behavior. The relative importance of these parameters on-system motion are quantified in a way that is useful for design purposes.
Kinetic Theory of Dynamical Systems
Zon, R. van; Beijeren, H. van; Dorfman, J.R.
1999-01-01
It is generally believed that the dynamics of simple fluids can be considered to be chaotic, at least to the extent that they can be modeled as classical systems of particles interacting with short range, repulsive forces. Here we give a brief introduction to those parts of chaos theory that are
Collective dynamics of multicellular systems
Indian Academy of Sciences (India)
simple model study reveals that cell–cell communication, system size and intrinsic cellular dynamics can lead to ... population/tissue interact, the ensemble can show a unified collective behaviour, which is not just a 'sum of the ..... Authors thank the anonymous referee for critical comments, and the Department of Science.
Mass properties measurement system dynamics
Doty, Keith L.
1993-01-01
The MPMS mechanism possess two revolute degrees-of-freedom and allows the user to measure the mass, center of gravity, and the inertia tensor of an unknown mass. The dynamics of the Mass Properties Measurement System (MPMS) from the Lagrangian approach to illustrate the dependency of the motion on the unknown parameters.
Growing B Lymphocytes in a Three-Dimensional Culture System
Wu, J. H. David; Bottaro, Andrea
2010-01-01
A three-dimensional (3D) culture system for growing long-lived B lymphocytes has been invented. The capabilities afforded by the system can be expected to expand the range of options for immunological research and related activities, including testing of immunogenicity of vaccine candidates in vitro, generation of human monoclonal antibodies, and immunotherapy. Mature lymphocytes, which are the effectors of adaptive immune responses in vertebrates, are extremely susceptible to apoptotic death, and depend on continuous reception of survival-inducing stimulation (in the forms of cytokines, cell-to-cell contacts, and antigen receptor signaling) from the microenvironment. For this reason, efforts to develop systems for long-term culture of functional, non-transformed and non-activated mature lymphocytes have been unsuccessful until now. The bone-marrow microenvironment supports the growth and differentiation of many hematopoietic lineages, in addition to B-lymphocytes. Primary bone-marrow cell cultures designed to promote the development of specific cell types in vitro are highly desirable experimental systems, amenable to manipulation under controlled conditions. However, the dynamic and complex network of stromal cells and insoluble matrix proteins is disrupted in prior plate- and flask-based culture systems, wherein the microenvironments have a predominantly two-dimensional (2D) character. In 2D bone-marrow cultures, normal B-lymphoid cells become progressively skewed toward precursor B-cell populations that do not retain a normal immunophenotype, and such mature B-lymphocytes as those harvested from the spleen or lymph nodes do not survive beyond several days ex vivo in the absence of mitogenic stimulation. The present 3D culture system is a bioreactor that contains highly porous artificial scaffolding that supports the long-term culture of bone marrow, spleen, and lymph-node samples. In this system, unlike in 2D culture systems, B-cell subpopulations developing
Adaptive, dynamic, and resilient systems
Suri, Niranjan
2015-01-01
As the complexity of today's networked computer systems grows, they become increasingly difficult to understand, predict, and control. Addressing these challenges requires new approaches to building these systems. Adaptive, Dynamic, and Resilient Systems supplies readers with various perspectives of the critical infrastructure that systems of networked computers rely on. It introduces the key issues, describes their interrelationships, and presents new research in support of these areas.The book presents the insights of a different group of international experts in each chapter. Reporting on r
Advanced dynamics of mechanical systems
Cheli, Federico
2015-01-01
This book introduces a general approach for schematization of mechanical systems with rigid and deformable bodies. It proposes a systems approach to reproduce the interaction of the mechanical system with different force fields such as those due to the action of fluids or contact forces between bodies, i.e., with forces dependent on the system states, introducing the concepts of the stability of motion. In the first part of the text mechanical systems with one or more degrees of freedom with large motion and subsequently perturbed in the neighborhood of the steady state position are analyzed. Both discrete and continuous systems (modal approach, finite elements) are analyzed. The second part is devoted to the study of mechanical systems subject to force fields, the rotor dynamics, techniques of experimental identification of the parameters, and random excitations. The book will be especially valuable for students of engineering courses in Mechanical Systems, Aerospace, Automation, and Energy but will also b...
Computation in Dynamically Bounded Asymmetric Systems
Rutishauser, Ueli; Slotine, Jean-Jacques; Douglas, Rodney
2015-01-01
Previous explanations of computations performed by recurrent networks have focused on symmetrically connected saturating neurons and their convergence toward attractors. Here we analyze the behavior of asymmetrical connected networks of linear threshold neurons, whose positive response is unbounded. We show that, for a wide range of parameters, this asymmetry brings interesting and computationally useful dynamical properties. When driven by input, the network explores potential solutions through highly unstable ‘expansion’ dynamics. This expansion is steered and constrained by negative divergence of the dynamics, which ensures that the dimensionality of the solution space continues to reduce until an acceptable solution manifold is reached. Then the system contracts stably on this manifold towards its final solution trajectory. The unstable positive feedback and cross inhibition that underlie expansion and divergence are common motifs in molecular and neuronal networks. Therefore we propose that very simple organizational constraints that combine these motifs can lead to spontaneous computation and so to the spontaneous modification of entropy that is characteristic of living systems. PMID:25617645
General flat four-dimensional world pictures and clock systems
Hsu, J. P.; Underwood, J. A.
1978-01-01
We explore the mathematical structure and the physical implications of a general four-dimensional symmetry framework which is consistent with the Poincare-Einstein principle of relativity for physical laws and with experiments. In particular, we discuss a four-dimensional framework in which all observers in different frames use one and the same grid of clocks. The general framework includes special relativity and a recently proposed new four-dimensional symmetry with a nonuniversal light speed as two special simple cases. The connection between the properties of light propagation and the convention concerning clock systems is also discussed, and is seen to be nonunique within the four-dimensional framework.
Rational solutions to two- and one-dimensional multicomponent Yajima–Oikawa systems
International Nuclear Information System (INIS)
Chen, Junchao; Chen, Yong; Feng, Bao-Feng; Maruno, Ken-ichi
2015-01-01
Exact explicit rational solutions of two- and one-dimensional multicomponent Yajima–Oikawa (YO) systems, which contain multi-short-wave components and single long-wave one, are presented by using the bilinear method. For two-dimensional system, the fundamental rational solution first describes the localized lumps, which have three different patterns: bright, intermediate and dark states. Then, rogue waves can be obtained under certain parameter conditions and their behaviors are also classified to above three patterns with different definition. It is shown that the simplest (fundamental) rogue waves are line localized waves which arise from the constant background with a line profile and then disappear into the constant background again. In particular, two-dimensional intermediate and dark counterparts of rogue wave are found with the different parameter requirements. We demonstrate that multirogue waves describe the interaction of several fundamental rogue waves, in which interesting curvy wave patterns appear in the intermediate times. Different curvy wave patterns form in the interaction of different types fundamental rogue waves. Higher-order rogue waves exhibit the dynamic behaviors that the wave structures start from lump and then retreat back to it, and this transient wave possesses the patterns such as parabolas. Furthermore, different states of higher-order rogue wave result in completely distinguishing lumps and parabolas. Moreover, one-dimensional rogue wave solutions with three states are constructed through the further reduction. Specifically, higher-order rogue wave in one-dimensional case is derived under the parameter constraints. - Highlights: • Exact explicit rational solutions of two-and one-dimensional multicomponent Yajima–Oikawa systems. • Two-dimensional rogue wave contains three different patterns: bright, intermediate and dark states. • Multi- and higher-order rogue waves exhibit distinct dynamic behaviors in two-dimensional case
Dynamical systems probabilistic risk assessment
Energy Technology Data Exchange (ETDEWEB)
Denman, Matthew R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ames, Arlo Leroy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2014-03-01
Probabilistic Risk Assessment (PRA) is the primary tool used to risk-inform nuclear power regulatory and licensing activities. Risk-informed regulations are intended to reduce inherent conservatism in regulatory metrics (e.g., allowable operating conditions and technical specifications) which are built into the regulatory framework by quantifying both the total risk profile as well as the change in the risk profile caused by an event or action (e.g., in-service inspection procedures or power uprates). Dynamical Systems (DS) analysis has been used to understand unintended time-dependent feedbacks in both industrial and organizational settings. In dynamical systems analysis, feedback loops can be characterized and studied as a function of time to describe the changes to the reliability of plant Structures, Systems and Components (SSCs). While DS has been used in many subject areas, some even within the PRA community, it has not been applied toward creating long-time horizon, dynamic PRAs (with time scales ranging between days and decades depending upon the analysis). Understanding slowly developing dynamic effects, such as wear-out, on SSC reliabilities may be instrumental in ensuring a safely and reliably operating nuclear fleet. Improving the estimation of a plant's continuously changing risk profile will allow for more meaningful risk insights, greater stakeholder confidence in risk insights, and increased operational flexibility.
Infinite-dimensional observer theory for dynamic estimation of neutron flux and xenon distributions
Energy Technology Data Exchange (ETDEWEB)
Park, Young Ho; Cho, Nam Zin [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)
1991-07-01
This paper describes a method for reconstructing the measurable and unmeasurable state variables in a nuclear reactor from output measurement data, which can be used to generate input of a feedback control system or to serve as a core observer (estimator) in reactor transient. The method is based on the Luenberger-type observer theory that is extended to infinite-dimensional distributed parameter systems. The method was applied to a simple reactor model in one spatial dimension and one energy group with xenon dynamics which exhibited spatial oscillations. The observer designed was tested by using model-based data for measurement output. The results showed that the spatial distributions of iodine, xenon and neutron flux were estimated by the observer very well using information from a finite number of sensors.
Dynamics of immune system vulnerabilities
Stromberg, Sean P.
The adaptive immune system can be viewed as a complex system, which adapts, over time, to reflect the history of infections experienced by the organism. Understanding its operation requires viewing it in terms of tradeoffs under constraints and evolutionary history. It typically displays "robust, yet fragile" behavior, meaning common tasks are robust to small changes but novel threats or changes in environment can have dire consequences. In this dissertation we use mechanistic models to study several biological processes: the immune response, the homeostasis of cells in the lymphatic system, and the process that normally prevents autoreactive cells from entering the lymphatic system. Using these models we then study the effects of these processes interacting. We show that the mechanisms that regulate the numbers of cells in the immune system, in conjunction with the immune response, can act to suppress autoreactive cells from proliferating, thus showing quantitatively how pathogenic infections can suppress autoimmune disease. We also show that over long periods of time this same effect can thin the repertoire of cells that defend against novel threats, leading to an age correlated vulnerability. This vulnerability is shown to be a consequence of system dynamics, not due to degradation of immune system components with age. Finally, modeling a specific tolerance mechanism that normally prevents autoimmune disease, in conjunction with models of the immune response and homeostasis we look at the consequences of the immune system mistakenly incorporating pathogenic molecules into its tolerizing mechanisms. The signature of this dynamic matches closely that of the dengue virus system.
A 2+1-Dimensional Non-Isothermal Magnetogasdynamic System. Hamiltonian-Ermakov Integrable Reduction
Directory of Open Access Journals (Sweden)
Hongli An
2012-08-01
Full Text Available A 2+1-dimensional anisentropic magnetogasdynamic system with a polytropic gas law is shown to admit an integrable elliptic vortex reduction when γ=2 to a nonlinear dynamical subsystem with underlying integrable Hamiltonian-Ermakov structure. Exact solutions of the magnetogasdynamic system are thereby obtained which describe a rotating elliptic plasma cylinder. The semi-axes of the elliptical cross-section, remarkably, satisfy a Ermakov-Ray-Reid system.
A 2+1-Dimensional Non-Isothermal Magnetogasdynamic System. Hamiltonian-Ermakov Integrable Reduction
An, Hongli; Rogers, Colin
2012-08-01
A 2+1-dimensional anisentropic magnetogasdynamic system with a polytropic gas law is shown to admit an integrable elliptic vortex reduction when γ=2 to a nonlinear dynamical subsystem with underlying integrable Hamiltonian-Ermakov structure. Exact solutions of the magnetogasdynamic system are thereby obtained which describe a rotating elliptic plasma cylinder. The semi-axes of the elliptical cross-section, remarkably, satisfy a Ermakov-Ray-Reid system.
Geometry of quantum dynamics in infinite-dimensional Hilbert space
Grabowski, Janusz; Kuś, Marek; Marmo, Giuseppe; Shulman, Tatiana
2018-04-01
We develop a geometric approach to quantum mechanics based on the concept of the Tulczyjew triple. Our approach is genuinely infinite-dimensional, i.e. we do not restrict considerations to finite-dimensional Hilbert spaces, contrary to many other works on the geometry of quantum mechanics, and include a Lagrangian formalism in which self-adjoint (Schrödinger) operators are obtained as Lagrangian submanifolds associated with the Lagrangian. As a byproduct we also obtain results concerning coadjoint orbits of the unitary group in infinite dimensions, embedding of pure states in the unitary group, and self-adjoint extensions of symmetric relations.
Simulation and sequential dynamical systems
Energy Technology Data Exchange (ETDEWEB)
Mortveit, H.S.; Reidys, C.M.
1999-06-01
Computer simulations have a generic structure. Motivated by this the authors present a new class of discrete dynamical systems that captures this structure in a mathematically precise way. This class of systems consists of (1) a loopfree graph {Upsilon} with vertex set {l_brace}1,2,{hor_ellipsis},n{r_brace} where each vertex has a binary state, (2) a vertex labeled set of functions (F{sub i,{Upsilon}}:F{sub 2}{sup n} {yields} F{sub 2}{sup n}){sub i} and (3) a permutation {pi} {element_of} S{sub n}. The function F{sub i,{Upsilon}} updates the state of vertex i as a function of the states of vertex i and its {Upsilon}-neighbors and leaves the states of all other vertices fixed. The permutation {pi} represents the update ordering, i.e., the order in which the functions F{sub i,{Upsilon}} are applied. By composing the functions F{sub i,{Upsilon}} in the order given by {pi} one obtains the dynamical system (equation given in paper), which the authors refer to as a sequential dynamical system, or SDS for short. The authors will present bounds for the number of functionally different systems and for the number of nonisomorphic digraphs {Gamma}[F{sub {Upsilon}},{pi}] that can be obtained by varying the update order and applications of these to specific graphs and graph classes.
A Three-Dimensional Wireless Indoor Localization System
Directory of Open Access Journals (Sweden)
Ping Yi
2014-01-01
Full Text Available Indoor localization, an emerging technology in location based service (LBS, is now playing a more and more important role both in commercial and in civilian industry. Global position system (GPS is the most popular solution in outdoor localization field, and the accuracy is around 10 meter error in positioning. However, with complex obstacles in buildings, problems rise in the “last mile” of localization field, which encourage a momentum of indoor localization. The traditional indoor localization system is either range-based or fingerprinting-based, which requires a lot of time and efforts to do the predeployment. In this paper, we present a 3-dimensional on-demand indoor localization system (3D-ODIL, which can be fingerprint-free and deployed rapidly in a multistorey building. The 3D-ODIL consists of two phases, vertical localization and horizontal localization. On vertical direction, we propose multistorey differential (MSD algorithm and implement it to fulfill the vertical localization, which can greatly reduce the number of anchors deployed. We use enhanced field division (EFD algorithm to conduct the horizontal localization. EFD algorithm is a range-free algorithm, the main idea of which is to dynamically divide the field within different signature area and position the target. The accuracy and performance have been validated through our extensive analysis and systematic experiments.
Acoustic dispersion in a two-dimensional dipole system
International Nuclear Information System (INIS)
Golden, Kenneth I.; Kalman, Gabor J.; Donko, Zoltan; Hartmann, Peter
2008-01-01
We calculate the full density response function and from it the long-wavelength acoustic dispersion for a two-dimensional system of strongly coupled point dipoles interacting through a 1/r 3 potential at arbitrary degeneracy. Such a system has no random-phase-approximation (RPA) limit and the calculation has to include correlations from the outset. We follow the quasilocalized charge (QLC) approach, accompanied by molecular-dynamics (MD) simulations. Similarly to what has been recently reported for the closely spaced classical electron-hole bilayer [G. J. Kalman et al., Phys. Rev. Lett. 98, 236801 (2007)] and in marked contrast to the RPA, we report a long-wavelength acoustic phase velocity that is wholly maintained by particle correlations and varies linearly with the dipole moment p. The oscillation frequency, calculated both in an extended QLC approximation and in the Singwi-Tosi-Land-Sjolander approximation [Phys. Rev. 176, 589 (1968)], is invariant in form over the entire classical to quantum domains all the way down to zero temperature. Based on our classical MD-generated pair distribution function data and on ground-state energy data generated by recent quantum Monte Carlo simulations on a bosonic dipole system [G. E. Astrakharchik et al., Phys. Rev. Lett. 98, 060405 (2007)], there is a good agreement between the QLC approximation kinetic sound speeds and the standard thermodynamic sound speeds in both the classical and quantum domains
Three-dimensional static and dynamic reactor calculations by the nodal expansion method
International Nuclear Information System (INIS)
Christensen, B.
1985-05-01
This report reviews various method for the calculation of the neutron-flux- and power distribution in an nuclear reactor. The nodal expansion method (NEM) is especially described in much detail. The nodal expansion method solves the diffusion equation. In this method the reactor core is divided into nodes, typically 10 to 20 cm in each direction, and the average flux in each node is calculated. To obtain the coupling between the nodes the local flux inside each node is expressed by use of a polynomial expansion. The expansion is one-dimensional, so inside each node such three expansions occur. To calculate the expansion coefficients it is necessary that the polynomial expansion is a solution to the one-dimensional diffusion equation. When the one-dimensional diffusion equation is established a term with the transversal leakage occur, and this term is expanded after the same polynomials. The resulting equation system with the expansion coefficients as the unknowns is solved with weigthed residual technique. The nodal expansion method is built into a computer program (also called NEM), which is divided into two parts, one part for steady-state calculations and one part for dynamic calculations. It is possible to take advantage of symmetry properties of the reactor core. The program is very flexible with regard to the number of energy groups, the node size, the flux expansion order and the transverse leakage expansion order. The boundary of the core is described by albedos. The program and input to it are described. The program is tested on a number of examples extending from small theoretical one up to realistic reactor cores. Many calculations are done on the wellknown IAEA benchmark case. The calculations have tested the accuracy and the computing time for various node sizes and polynomial expansions. In the dynamic examples various strategies for variation of the time step-length have been tested. (author)
Alignment dynamics of diffusive scalar gradient in a two-dimensional model flow
Gonzalez, M.
2018-04-01
The Lagrangian two-dimensional approach of scalar gradient kinematics is revisited accounting for molecular diffusion. Numerical simulations are performed in an analytic, parameterized model flow, which enables considering different regimes of scalar gradient dynamics. Attention is especially focused on the influence of molecular diffusion on Lagrangian statistical orientations and on the dynamics of scalar gradient alignment.
Fujimoto, Kazuya; Hamazaki, Ryusuke; Ueda, Masahito
2018-02-01
By studying the coarsening dynamics of a one-dimensional spin-1 Bose-Hubbard model in a superfluid regime, we analytically find an unconventional universal dynamical scaling for the growth of the spin correlation length, which is characterized by the exponential integral unlike the conventional power law or simple logarithmic behavior, and numerically confirmed with the truncated Wigner approximation.
Expansion of derivatives in one-dimensional dynamics
Bruin, H; van Strien, S
2003-01-01
We study the expansion of derivatives along orbits of real and complex one-dimensional maps f, whose Julia set J(f) attracts a finite set Crit of non-flat critical points. Assuming that for each c is an element of Crit, either \\Df(n)(f(c))\\ --> infinity (if f is real) or b(n) (.) \\Df(n)(f(c))\\ -->
Polaron dynamics in a two-dimensional anharmonic Holstein model
DEFF Research Database (Denmark)
Zolotaryuk, Yaroslav; Christiansen, Peter Leth; Juul Rasmussen, Jens
1998-01-01
A generalized two-dimensional semiclassical :Holstein model with a realistic on-site potential that contains anharmonicity is studied. More precisely, the lattice subsystem of anharmonic on-site oscillators is supposed to have a restricting core. The core plays the role of an effective saturation...
Investigation of the 16O+194Pt reaction: One- and two-dimensional dynamical interpretation
Naderi, D.; Farmani, A.
In this paper, we applied the Langevin dynamical model to investigate the different aspects of the 16O+194Pt reaction. Elongation and orientation degree of freedom (K coordinate) which are the first and second dimensions of dynamical calculations, are presented here. Fission time, fission cross-section, pre-scission neutron multiplicity, and fission probability were calculated using one- and two-dimensional Langevin equations. Also, anisotropy of fission-fragments angular distribution has been investigated based on the transition state model, one- and two-dimensional Langevin dynamical models. It was found that by adding the orientation degree of freedom to calculations, the fission time and pre-scission neutrons multiplicity increases whereas fission cross-section, and fission probability decreases. The two-dimensional dynamical calculations are a better match to the experimental data than the one-dimensional dynamical calculations, when using nominal values for the reduced dissipation coefficient and shape-dependent level density parameter. However, if model parameters are adjusted to reproduce the fission cross-section data, then both the one- and two-dimensional models give a satisfactory match to the fission fragment anisotropy data. Nonequilibrium K distributions in the dynamical model can better explain the experimental anisotropy of the angular distribution of fission-fragments with respect to the equilibrium K distribution in saddle and scission point transition state models.
Synchronization of nonautonomous dynamical systems
Directory of Open Access Journals (Sweden)
Peter E. Kloeden
2003-04-01
Full Text Available The synchronization of two nonautonomous dynamical systems is considered, where the systems are described in terms of a skew-product formalism, i. e., in which an inputed autonomous driving system governs the evolution of the vector field of a differential equation with the passage of time. It is shown that the coupled trajectories converge to each other as time increases for sufficiently large coupling coefficient and also that the component sets of the pullback attractor of the coupled system converges upper semi continuously as the coupling parameter increases to the diagonal of the product of the corresponding component sets of the pullback attractor of a system generated by the average of the vector fields of the original uncoupled systems.
Multisoliton formula for completely integrable two-dimensional systems
International Nuclear Information System (INIS)
Chudnovsky, D.V.; Chudnovsky, G.V.
1979-01-01
For general two-dimensional completely integrable systems, the exact formulae for multisoliton type solutions are given. The formulae are obtained algebrically from solutions of two linear partial differential equations
Approximate Dynamic Programming Solving the Curses of Dimensionality
Powell, Warren B
2011-01-01
Praise for the First Edition "Finally, a book devoted to dynamic programming and written using the language of operations research (OR)! This beautiful book fills a gap in the libraries of OR specialists and practitioners."-Computing Reviews This new edition showcases a focus on modeling and computation for complex classes of approximate dynamic programming problems Understanding approximate dynamic programming (ADP) is vital in order to develop practical and high-quality solutions to complex industrial problems, particularly when those problems involve making decisions in the presence of unce
Metastable and scaling regimes of one-dimensional Kawasaki dynamics
Albarracín, F. A. Gómez; Rosales, H. D.; Grynberg, M. D.
2016-04-01
We investigate the large-time scaling regimes arising from a variety of metastable structures in a chain of Ising spins with both first- and second-neighbor couplings while subject to Kawasaki dynamics. Depending on the ratio and sign of these former, different dynamic exponents are suggested by finite-size scaling analyses of relaxation times. At low but nonzero temperatures these are calculated via exact diagonalizations of the evolution operator in finite chains under several activation barriers. In the absence of metastability the dynamics is always diffusive.
Dynamical Systems and Motion Vision.
1988-04-01
TASK Artificial Inteligence Laboratory AREA I WORK UNIT NUMBERS 545 Technology Square . Cambridge, MA 02139 C\\ II. CONTROLLING OFFICE NAME ANO0 ADDRESS...INSTITUTE OF TECHNOLOGY ARTIFICIAL INTELLIGENCE LABORATORY A.I.Memo No. 1037 April, 1988 Dynamical Systems and Motion Vision Joachim Heel Abstract: In this... Artificial Intelligence L3 Laboratory of the Massachusetts Institute of Technology. Support for the Laboratory’s [1 Artificial Intelligence Research is
Dynamic Response of Wall Backfill Retaining System
Directory of Open Access Journals (Sweden)
Sreenivas Alampalli
1997-01-01
Full Text Available An in situ full-scale test is conducted to measure the dynamic response of a long cantilever wall that retains backfill soil. The recorded modal parameters of this retaining wall exhibited significant similarity to those of a clamped cantilever plate (rather than those of a cantilever beam or plane-strain analysis. Such a three-dimensional (3-D response pattern is not accounted for by current analysis procedures. A simple 3-D finite element model is employed to further analyze the observed resonant configurations. The results indicate that such configurations play an important role in the seismic response of wall backfill soil systems of variable height, such as wing walls supporting highway approach ramps.
On Rank Driven Dynamical Systems
Veerman, J. J. P.; Prieto, F. J.
2014-08-01
We investigate a class of models related to the Bak-Sneppen (BS) model, initially proposed to study evolution. The BS model is extremely simple and yet captures some forms of "complex behavior" such as self-organized criticality that is often observed in physical and biological systems. In this model, random fitnesses in are associated to agents located at the vertices of a graph . Their fitnesses are ranked from worst (0) to best (1). At every time-step the agent with the worst fitness and some others with a priori given rank probabilities are replaced by new agents with random fitnesses. We consider two cases: The exogenous case where the new fitnesses are taken from an a priori fixed distribution, and the endogenous case where the new fitnesses are taken from the current distribution as it evolves. We approximate the dynamics by making a simplifying independence assumption. We use Order Statistics and Dynamical Systems to define a rank-driven dynamical system that approximates the evolution of the distribution of the fitnesses in these rank-driven models, as well as in the BS model. For this simplified model we can find the limiting marginal distribution as a function of the initial conditions. Agreement with experimental results of the BS model is excellent.
Savin, Alexander V.; Kosevich, Yuriy A.; Cantarero, Andres
2012-08-01
We present a detailed description of semiquantum molecular dynamics simulation of stochastic dynamics of a system of interacting particles. Within this approach, the dynamics of the system is described with the use of classical Newtonian equations of motion in which the effects of phonon quantum statistics are introduced through random Langevin-like forces with a specific power spectral density (the color noise). The color noise describes the interaction of the molecular system with the thermostat. We apply this technique to the simulation of thermal properties and heat transport in different low-dimensional nanostructures. We describe the determination of temperature in quantum lattice systems, to which the equipartition limit is not applied. We show that one can determine the temperature of such a system from the measured power spectrum and temperature- and relaxation-rate-independent density of vibrational (phonon) states. We simulate the specific heat and heat transport in carbon nanotubes, as well as the heat transport in molecular nanoribbons with perfect (atomically smooth) and rough (porous) edges, and in nanoribbons with strongly anharmonic periodic interatomic potentials. We show that the effects of quantum statistics of phonons are essential for the carbon nanotube in the whole temperature range T<500K, in which the values of the specific heat and thermal conductivity of the nanotube are considerably less than that obtained within the description based on classical statistics of phonons. This conclusion is also applicable to other carbon-based materials and systems with high Debye temperature like graphene, graphene nanoribbons, fullerene, diamond, diamond nanowires, etc. We show that the existence of rough edges and quantum statistics of phonons change drastically the low-temperature thermal conductivity of the nanoribbon in comparison with that of the nanoribbon with perfect edges and classical phonon dynamics and statistics. The semiquantum molecular
Dynamics and Control of Three-Dimensional Perching Maneuver under Dynamic Stall Influence
Feroskhan, Mir Alikhan Bin Mohammad
Perching is a type of aggressive maneuver performed by the class 'Aves' species to attain precision point landing with a generally short landing distance. Perching capability is desirable on unmanned aerial vehicles (UAVs) due to its efficient deceleration process that potentially expands the functionality and flight envelope of the aircraft. This dissertation extends the previous works on perching, which is mostly limited to two-dimensional (2D) cases, to its state-of-the-art threedimensional (3D) variety. This dissertation presents the aerodynamic modeling and optimization framework adopted to generate unprecedented variants of the 3D perching maneuver that include the sideslip perching trajectory, which ameliorates the existing 2D perching concept by eliminating the undesirable undershoot and reliance on gravity. The sideslip perching technique methodically utilizes the lateral and longitudinal drag mechanisms through consecutive phases of yawing and pitching-up motion. Since perching maneuver involves high rates of change in the angles of attack and large turn rates, introduction of three internal variables thus becomes necessary for addressing the influence of dynamic stall delay on the UAV's transient post-stall behavior. These variables are then integrated into a static nonlinear aerodynamic model, developed using empirical and analytical methods, and into an optimization framework that generates a trajectory of sideslip perching maneuver, acquiring over 70% velocity reduction. An impact study of the dynamic stall influence on the optimal perching trajectories suggests that consideration of dynamic stall delay is essential due to the significant discrepancies in the corresponding control inputs required. A comparative study between 2D and 3D perching is also conducted to examine the different drag mechanisms employed by 2D and 3D perching respectively. 3D perching is presented as a more efficient deceleration technique with respect to spatial costs and
Approximate dynamic programming solving the curses of dimensionality
Powell, Warren B
2007-01-01
Warren B. Powell, PhD, is Professor of Operations Research and Financial Engineering at Princeton University, where he is founder and Director of CASTLE Laboratory, a research unit that works with industrial partners to test new ideas found in operations research. The recipient of the 2004 INFORMS Fellow Award, Dr. Powell has authored over 100 refereed publications on stochastic optimization, approximate dynamic programming, and dynamic resource management.
Classical and quantum phases of low-dimensional dipolar systems
Energy Technology Data Exchange (ETDEWEB)
Cartarius, Florian
2016-09-22
In this thesis we present a detailed study of the phase diagram of ultracold bosonic atoms confined along a tight atomic wave guide, along which they experience an optical lattice potential. In this quasi-one dimensional model we analyse the interplay between interactions and quantum fluctuations in (i) determining the non-equilibrium steady state after a quench and (ii) giving rise to novel equilibrium phases, when the interactions combine the s-wave contact interaction and the anisotropic long range dipole-dipole interactions. In detail, in the first part of the thesis we study the depinning of a gas of impenetrable bosons following the sudden switch of of the optical lattice. By means of a Bose-Fermi mapping we infer the exact quantum dynamical evolution and show that in the thermodynamic limit the system is in a non-equilibrium steady state without quasi-long range order. In the second part of the thesis, we study the effect of quantum fluctuations on the linear-zigzag instability in the ground state of ultracold dipolar bosons, as a function of the strength of the transverse confinement. We first analyse the linear-zigzag instability in the classical regime, and then use our results to develop a multi-mode Bose-Hubbard model for the system. We then develop several numerical methods, to determine the ground state.
Monsoon convection dynamics and nonlinear dimensionality reduction vis Isomap
Hannachi, A.; Turner, A.
2012-04-01
The Asian summer monsoon is a high dimensional and highly nonlinear phenomenon involving considerable moisture transport into land from ocean, and is critical for the whole region. We have used the European Reanalysis ERA-40 sea-level pressure (SLP) anomalies, with respect to the seasonal cycle, over the region (50E-145E, 20S-35N) to study the nonlinearity of the Asian monsoon using Isomap. We have focussed on the two-dimensional embedding of the SLP anomalies. Unlike the unimodality obtained from the empirical orthogonal function space, the probability density function computed within the two-dimensional Isomap space is shown to be bimodal. A clustering procedure is applied and reveals that the data support three clusters, which are identified using a three-component bivariate Gaussian mixture model. Two modes are associated with an active phase over India/Bay of Bengal and East China sea respectively, whereas the third mode is associated witha break over East/South China sea. Using the low-level wind field anomalies the (first mode) active phase is found to be characterised by a strengthening and an eastward extension of the Somali jet whereas during the (second mode) break phase the Somali jet is weakened and reversed by an easterly flow emanating from the West Pacific. The effect of large scale seasonal mean monsoon and lower boundary forcing is also investigated and discussed.
Dynamics and predictability of Asian Monsoon and nonlinear dimensionality reduction
Hannachi, Abdel; Turner, Andy
2013-04-01
The Asian summer monsoon is a high dimensional and highly nonlinear phenomenon involving considerable moisture transport into land from ocean, and is critical for the whole region. We have used the European Reanalysis ERA-40 sea-level pressure (SLP) anomalies, with respect to the seasonal cycle, over the region (50E-145E, 20S-35N) to study the nonlinearity of the Asian monsoon using Isomap. We have focussed on the two-dimensional embedding of the SLP anomalies. Unlike the unimodality obtained from the empirical orthogonal function space, the probability density function, within the two-dimensional Isomap space, turns out to be bimodal. A clustering procedure is applied and reveals that the data support three clusters, which are identified using a three-component bivariate Gaussian mixture model. The modes are found to be associated respectively with the break and the active phases of the monsoon in addition to a third phase: the China sea active phase. Using the low-level wind field anomalies the active phase is found to be characterised by a strengthening and an eastward extension of the Somali jet whereas during the break phase the Somali jet is weakened and reversed by an easterly flow emanating from the West Pacific. The effect of large scale seasonal mean monsoon and lower boundary forcing is also investigated and discussed.
Energy Technology Data Exchange (ETDEWEB)
Bustamante, Miguel D [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile (Chile); Hojman, Sergio A [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile (Chile)
2003-01-10
In this paper, we consider the general setting for constructing action principles for three-dimensional first-order autonomous equations. We present the results for some integrable and non-integrable cases of the Lotka-Volterra equation, and show Lagrangian descriptions which are valid for systems satisfying Shil'nikov criteria on the existence of strange attractors, though chaotic behaviour has not been verified up to now. The Euler-Lagrange equations we get for these systems usually present 'time reparametrization' invariance, though other kinds of invariance may be found according to the kernel of the associated symplectic 2-form. The formulation of a Hamiltonian structure (Poisson brackets and Hamiltonians) for these systems from the Lagrangian viewpoint leads to a method of finding new constants of the motion starting from known ones, which is applied to some systems found in the literature known to possess a constant of the motion, to find the other and thus showing their integrability. In particular, we show that the so-called ABC system is completely integrable if it possesses one constant of the motion.
Experimental Modeling of Dynamic Systems
DEFF Research Database (Denmark)
Knudsen, Morten Haack
2006-01-01
An engineering course, Simulation and Experimental Modeling, has been developed that is based on a method for direct estimation of physical parameters in dynamic systems. Compared with classical system identification, the method appears to be easier to understand, apply, and combine with physical...... insight. It is based on a sensitivity approach that is useful for choice of model structure, for experiment design, and for accuracy verification. The method is implemented in the Matlab toolkit Senstools. The method and the presentation have been developed with generally preferred learning styles in mind...
Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate
Reichhardt, C.; Reichhardt, C. J. Olson
2016-09-01
We numerically examine driven skyrmions interacting with a periodic quasi-one-dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinal to the driving direction. Within the longitudinally locked phase we find a pronounced speedup effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speedup effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. We map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.
Energy Technology Data Exchange (ETDEWEB)
Butkus, Vytautas; Gelzinis, Andrius; Valkunas, Leonas [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Center for Physical Sciences and Technology, Savanoriu Ave. 231, 02300 Vilnius (Lithuania); Augulis, Ramūnas [Center for Physical Sciences and Technology, Savanoriu Ave. 231, 02300 Vilnius (Lithuania); Gall, Andrew; Robert, Bruno [Institut de Biologie et Technologies de Saclay, Bât 532, Commissariat à l’Energie Atomique Saclay, 91191 Gif sur Yvette (France); Büchel, Claudia [Institut für Molekulare Biowissenschaften, Universität Frankfurt, Max-von-Laue-Straße 9, Frankfurt (Germany); Zigmantas, Donatas [Department of Chemical Physics, Lund University, P.O. Box 124, 22100 Lund (Sweden); Abramavicius, Darius, E-mail: darius.abramavicius@ff.vu.lt [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania)
2015-06-07
Energy transfer processes and coherent phenomena in the fucoxanthin–chlorophyll protein complex, which is responsible for the light harvesting function in marine algae diatoms, were investigated at 77 K by using two-dimensional electronic spectroscopy. Experiments performed on femtosecond and picosecond timescales led to separation of spectral dynamics, witnessing evolutions of coherence and population states of the system in the spectral region of Q{sub y} transitions of chlorophylls a and c. Analysis of the coherence dynamics allowed us to identify chlorophyll (Chl) a and fucoxanthin intramolecular vibrations dominating over the first few picoseconds. Closer inspection of the spectral region of the Q{sub y} transition of Chl c revealed previously not identified, mutually non-interacting chlorophyll c states participating in femtosecond or picosecond energy transfer to the Chl a molecules. Consideration of separated coherent and incoherent dynamics allowed us to hypothesize the vibrations-assisted coherent energy transfer between Chl c and Chl a and the overall spatial arrangement of chlorophyll molecules.
Fully three-dimensional analysis of high-speed train-track-soil-structure dynamic interaction
Galvín, P.; Romero, A.; Domínguez, J.
2010-11-01
In this paper, a general and fully three dimensional multi-body-finite element-boundary element model, formulated in the time domain to predict vibrations due to train passage at the vehicle, the track and the free field, is presented. The vehicle is modelled as a multi-body system and, therefore, the quasi-static and the dynamic excitation mechanisms due to train passage can be considered. The track is modelled using finite elements. The soil is considered as a homogeneous half-space by the boundary element method. This methodology could be used to take into account local soil discontinuities, underground constructions such as underpasses, and coupling with nearby structures that break the uniformity of the geometry along the track line. The nonlinear behaviour of the structures could be also considered. In the present paper, in order to test the model, vibrations induced by high-speed train passage are evaluated for a ballasted track. The quasi-static and dynamic load components are studied and the influence of the suspended mass on the vertical loads is analyzed. The numerical model is validated by comparison with experimental records from two HST lines. Finally, the dynamic behaviour of a transition zone between a ballast track and a slab track is analyzed and the obtained results from the proposed model are compared with those obtained from a model with invariant geometry with respect to the track direction.
Interaction and dynamics of add-atoms with 2-dimensional structures
The interaction and dynamics of add-atoms with graphene, graphene-derivate structures and, later, MoSi$_2$, two-dimensional – single and few – atomic layers will be studied with the Perturbed Angular Correlation – PAC – technique. Graphene is also envisaged as new platform for growing semiconductor nanostructure devices, such as quantum dots and as a particularly powerful catalyst. Understanding nucleation of nanostructures and clusters on graphene and related phases in wet conditions as they are used in chemical methods in research and industry require complementary studies. These systems will therefore be studied systematically using radioactive probe atoms attaching via a transfer media (e.g., water in catalysis process) or being deposited with soft-landing techniques under vacuum and UHV conditions, as put in place at the ASPIC setup at ISOLDE. The hyperfine fields obtained under different environments are expected to reveal basic information on the rich atomic and physical mechanisms associated w...
UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.
Chang, Kai; Xia, Yuanqing; Huang, Kaoli
2016-01-01
This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method.
Molecular dynamics of shock waves in one-dimensional chains. II. Thermalization
International Nuclear Information System (INIS)
Straub, G.K.; Holian, B.L.; Petschek, R.G.
1979-01-01
The thermalization behavior behind a shock front in one-dimensional chains has been studied in a series of molecular-dynamics computer experiments. We have found that a shock wave generated in a chain initially at finite temperature has essentially the same characteristics as in a chain initially at zero temperature. We also find that the final velocity distribution function for particles behind the shock front is not the Maxwell-Boltzmann distribution for an equilibrium system of classical particles. For times long after the shock has passed, we propose a nonequilibrium velocity distribution which is based upon behavior in the harmonic and hard-rod limits and agrees with our numerical results. Temperature profiles for both harmonic and anharmonic chains are found to exhibit a long-time tail that decays inversely with time. Finally, we have run a computer experiment to generate what qualitatively resembles solitons in Toda chains by means of shock waves
The theory of critical phenomena in two-dimensional systems
International Nuclear Information System (INIS)
Olvera de la C, M.
1981-01-01
An exposition of the theory of critical phenomena in two-dimensional physical systems is presented. The first six chapters deal with the mean field theory of critical phenomena, scale invariance of the thermodynamic functions, Kadanoff's spin block construction, Wilson's renormalization group treatment of critical phenomena in configuration space, and the two-dimensional Ising model on a triangular lattice. The second part of this work is made of four chapters devoted to the application of the ideas expounded in the first part to the discussion of critical phenomena in superfluid films, two-dimensional crystals and the two-dimensional XY model of magnetic systems. Chapters seven to ten are devoted to the following subjects: analysis of long range order in one, two, and three-dimensional physical systems. Topological defects in the XY model, in superfluid films and in two-dimensional crystals. The Thouless-Kosterlitz iterated mean field theory of the dipole gas. The renormalization group treatment of the XY model, superfluid films and two-dimensional crystal. (author)
Static configurations and evolution of higher dimensional brane-dilaton black hole system
Energy Technology Data Exchange (ETDEWEB)
Nakonieczna, Anna [Institute of Physics, Maria Curie-Skłodowska University,Plac Marii Curie-Skłodowskiej 1, 20-031 Lublin (Poland); Institute of Theoretical Physics, Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warsaw (Poland); Nakonieczny, Łukasz [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warsaw (Poland); Moderski, Rafał [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences,ul. Bartycka 18, 00-716 Warsaw (Poland); Rogatko, Marek [Institute of Physics, Maria Curie-Skłodowska University,Plac Marii Curie-Skłodowskiej 1, 20-031 Lublin (Poland)
2016-12-15
Static configurations and a dynamical evolution of the system composed of a higher-dimensional spherically symmetric dilaton black hole and the Dirac-Goto-Nambu brane were investigated. The studies were conducted for three values of the dilaton coupling constant, describing the uncoupled case, the low-energy limit of the string theory and dimensionally reduced Klein-Kaluza theories. When the black hole is nonextremal, two types of static configurations are observed, a brane which intersects the black hole horizon and a brane not having any common points with the accompanying black hole. As the number of spacetime dimensions increases, the brane bend in the vicinity of the black hole disappears closer to its horizon. Dynamical evolution of the system results in an expulsion of the black hole from the brane. It proceeds faster for bigger values of the bulk spacetime dimension and thicker branes. The value of the dilatonic coupling constant does not influence neither the static configurations nor the dynamical behavior of the examined nonextremal system. In the extremal dilaton black hole case one obtains expulsion of the brane which is independent on the spacetime dimensionality and the value of the coupling constant. Dynamical studies of the configurations in the extremal case reveal that the course of evolution of the system is similar to the nonextremal one, except for a slightly earlier expulsion of the black hole from the brane.
Directory of Open Access Journals (Sweden)
Musa Danjuma SHEHU
2008-06-01
Full Text Available This paper lays emphasis on formulation of two dimensional differential games via optimal control theory and consideration of control systems whose dynamics is described by a system of Ordinary Differential equation in the form of linear equation under the influence of two controls U(. and V(.. Base on this, strategies were constructed. Hence we determine the optimal strategy for a control say U(. under a perturbation generated by the second control V(. within a given manifold M.
International Nuclear Information System (INIS)
1977-01-01
The TRICO part of the CEA-SEMT system is concerned with the elasticity or plasticity computation of structures made of thin shells and beams. TRICO uses the finite element method for shells and beams. TRICO also allows the dynamic computing of structures: search for eigenmodes and eigenfrequencies or response to any sinusoidal excitation, response to time dependent loads (direct integration) in elasticity or plasticity. The mechanical structures can offer any shape and be composed of a number of materials. A special effort has been put on data input (read without any format), the data being arranged in optional commands with a precise physical sense corresponding to an order for the program. A dynamic control of the memory allows the size of the program to be adapted to that the problem to be processed. Results are printed on listing, or many be described on a magnetic tape [fr
Dynamic Three-Dimensional Geometry of the Aortic Valve Apparatus-A Feasibility Study.
Khamooshian, Arash; Amador, Yannis; Hai, Ting; Jeganathan, Jelliffe; Saraf, Maria; Mahmood, Eitezaz; Matyal, Robina; Khabbaz, Kamal R; Mariani, Massimo; Mahmood, Feroze
2017-08-01
To provide (1) an overview of the aortic valve (AV) apparatus anatomy and nomenclature, and (2) data regarding the normal AV apparatus geometry and dynamism during the cardiac cycle obtained from three-dimensional transesophageal echocardiography (3D TEE). Retrospective feasibility study. A single-center university teaching hospital. The study was performed on data of 10 patients with a nonregurgitant, nonstenotic aortic valve undergoing cardiac surgery. Intraoperative 3D TEE was performed on all the participants using the Siemens ACUSON SC2000 ultrasound system and Z6Ms transducer (Siemens Medical Systems, Mountainview, CA). Dynamic offline analyses were performed with Siemens eSie valve analytical software in a semiautomated fashion. Forty-five parameters were exported of which 13 were selected and analyzed. The cardiac cycle was divided into 4 quartiles to account for frame-rate variations. The annulus, sinus of Valsalva (SoV) and sinotubular junction (STJ) areas, diameter, perimeter and height, aortic leaflet height, leaflet coaptation height, and aortic valve-mitral valve angle changed significantly during the cardiac cycle (p < 0.001). STJ expanded more than both the annulus and the SoV (p < 0.001). The maximum aortic valve leaflet height change was greater in the left and right versus noncoronary leaflet (p < 0.001). The semiautomated AV apparatus dynamic assessment using eSie valve software is a clinically feasible technique and can be performed readily in the operating room. It has the potential to significantly impact intraoperative decision-making in cases suitable for AV repair. The AV apparatus is a dynamic structure and demonstrates significant changes during the cardiac cycle. Copyright © 2017. Published by Elsevier Inc.
Substitution dynamical systems spectral analysis
Queffélec, Martine
2010-01-01
This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...
Dynamical System Approaches to Combinatorial Optimization
DEFF Research Database (Denmark)
Starke, Jens
2013-01-01
Several dynamical system approaches to combinatorial optimization problems are described and compared. These include dynamical systems derived from penalty methods; the approach of Hopfield and Tank; self-organizing maps, that is, Kohonen networks; coupled selection equations; and hybrid methods...
Confinement and dynamical regulation in two-dimensional convective turbulence
DEFF Research Database (Denmark)
Bian, N.H.; Garcia, O.E.
2003-01-01
In this work the nature of confinement improvement implied by the self-consistent generation of mean flows in two-dimensional convective turbulence is studied. The confinement variations are linked to two distinct regulation mechanisms which are also shown to be at the origin of low......-frequency bursting in the fluctuation level and the convective heat flux integral, both resulting in a state of large-scale intermittency. The first one involves the control of convective transport by sheared mean flows. This regulation relies on the conservative transfer of kinetic energy from tilted fluctuations...
System dynamics in hydropower plants
Energy Technology Data Exchange (ETDEWEB)
Stuksrud, Dag Birger
1998-12-31
The main purpose of this thesis on system dynamics in hydropower plants was to establish new models of a hydropower system where the turbine/conduits and the electricity supply and generation are connected together as one unit such that possible interactions between the two power regimes can be studied. In order to describe the system dynamics as well as possible, a previously developed analytic model of high-head Francis turbines is improved. The model includes the acceleration resistance in the turbine runner and the draft tube. Expressions for the loss coefficients in the model are derived in order to obtain a purely analytic model. The necessity of taking the hydraulic inertia into account is shown by means of simulations. Unstable behaviour and a higher transient turbine speed than expected may occur for turbines with steep characteristics or large draft tubes. The turbine model was verified previously with respect to a high-head Francis turbine; the thesis performs an experimental verification on a low-head Francis turbine and compares the measurements with simulations from the improved turbine model. It is found that the dynamic turbine model is, after adjustment, capable of describing low-head machines as well with satisfying results. The thesis applies a method called the ``Limited zero-pole method`` to obtain new rational approximations of the elastic behaviour in the conduits with frictional damping included. These approximations are used to provide an accurate state space formulation of a hydropower plant. Simulations performed with the new computer programs show that hydraulic transients such as water-hammer and mass oscillations are reflected in the electric grid. Unstable governing performance in the electric and hydraulic parts also interact. This emphasizes the need for analysing the whole power system as a unit. 63 refs., 149 figs., 4 tabs.
Linear stability theory as an early warning sign for transitions in high dimensional complex systems
International Nuclear Information System (INIS)
We analyse in detail a new approach to the monitoring and forecasting of the onset of transitions in high dimensional complex systems by application to the Tangled Nature model of evolutionary ecology and high dimensional replicator systems with a stochastic element. A high dimensional stability matrix is derived in the mean field approximation to the stochastic dynamics. This allows us to determine the stability spectrum about the observed quasi-stable configurations. From overlap of the instantaneous configuration vector of the full stochastic system with the eigenvectors of the unstable directions of the deterministic mean field approximation, we are able to construct a good early-warning indicator of the transitions occurring intermittently. (paper)
Quantum vortex dynamics in two-dimensional neutral superfluids
Wang, C. -C J.; Duine, R.A.; MacDonald, A.H.
2010-01-01
We derive an effective action for the vortex-position degree of freedom in a superfluid by integrating out condensate phase- and density-fluctuation environmental modes. When the quantum dynamics of environmental fluctuations is neglected, we confirm the occurrence of the vortex Magnus force and
Impurity states in two and three dimensional disordered system S
International Nuclear Information System (INIS)
Silva, A.F. da; Fabbri, M.
1984-01-01
We investigate the microscopic structure of the impurity states in two-and three-dimensional (2D and 3D) disordered system. A cluster model is outlined for the donor impurity density of states (DIDS) of doped semiconductors. It is shown that the impurity states are very sensitive to a change in the dimensionality of the system, i.e., from 3D to 2D system. It is found that all eigenstates become localized in 2D disordered system for a large range of concentration. (author) [pt
Two-dimensional NMR investigations of the dynamic conformations of phospholipids and liquid crystals
Energy Technology Data Exchange (ETDEWEB)
Hong, Mei [Univ. of California, Berkeley, CA (United States). Applied Science and Technology
1996-05-01
Two-dimensional 13C, 1H, and 31P nuclear magnetic resonance (NMR) techniques are developed and used to study molecular structure and dynamics in liquid-crystalline systems, primarily phospholipids and nematic liquid crystals. NMR spectroscopy characterizes molecular conformation in terms of orientations and distances of molecular segments. In anisotropically mobile systems, this is achieved by measuring motionally-averaged nuclear dipolar couplings and chemical shift anisotropies. The short-range couplings yield useful bond order parameters, while the long-range interactions constrain the overall conformation. In this work, techniques for probing proton dipolar local fields are further developed to obtain highlyresolved dipolar couplings between protons and rare spins. By exploiting variable-angle sample spinning techniques, orientation-sensitive NMR spectra are resolved according to sitespecific isotropic chemical shifts. Moreover, the signs and magnitudes of various short-range dipolar couplings are obtained. They are used in novel theoretical analyses that provide information about segmental orientations and their distributions. Such information is obtained in a model-independent fashion or with physically reasonable assumptions. The structural investigation of phospholipids is focused on the dynam
A study of low-dimensional inhomogeneous systems
International Nuclear Information System (INIS)
Arredondo Leon, Yesenia
2009-01-01
While the properties of homogeneous one-dimensional systems, even with disorder, are relatively well-understood, very little is known about the properties of strongly interacting inhomogeneous systems. Their high-energy physics is determined by the underlying chemistry which, in the atomic scale, introduces Coulomb correlations and local potentials. On the other hand, at large length scales, the physics has to be described by the Tomonaga-Luttinger liquid (TLL) model. In order to establish a connection between the low-energy TLL and the quasi-one-dimensional systems synthesized in the laboratory, we investigate the density-density correlation function in inhomogeneous one-dimensional systems in the asymptotic region. To investigate homogeneous as well as inhomogeneous systems, we use the density-matrix renormalization group (DMRG) method. We present results for ground state properties, such as the density-density correlation function and the parameter K c , which characterizes its decay at large distances. (orig.)
One-dimensional rainbow thermometry system by using slit apertures.
Wu, Xuecheng; Jiang, Haoyu; Wu, Yingchun; Song, Jin; Gréhan, Gérard; Saengkaew, Sawitree; Chen, Linghong; Gao, Xiang; Cen, Kefa
2014-02-01
A new rainbow thermometry system by using slit apertures and a laser light sheet, called a one-dimensional rainbow thermometry (ORT) system, has been developed as an extension of global rainbow thermometry (GRT). This system is capable of one-dimensional or line measurements of the size and refractive index of droplets in the spray space, while the conventional GRT system is normally considered a typical "single-point" or "small volume" measurement method. The performance of this new system was tested and verified with both water and ethanol spray. The results show the feasibility and potential of ORT in simultaneous and one-dimensional measurement of the size and refractive index of liquid droplets, especially in the research field of spray evaporation and combustion.
A study of low-dimensional inhomogeneous systems
Energy Technology Data Exchange (ETDEWEB)
Arredondo Leon, Yesenia
2009-01-15
While the properties of homogeneous one-dimensional systems, even with disorder, are relatively well-understood, very little is known about the properties of strongly interacting inhomogeneous systems. Their high-energy physics is determined by the underlying chemistry which, in the atomic scale, introduces Coulomb correlations and local potentials. On the other hand, at large length scales, the physics has to be described by the Tomonaga-Luttinger liquid (TLL) model. In order to establish a connection between the low-energy TLL and the quasi-one-dimensional systems synthesized in the laboratory, we investigate the density-density correlation function in inhomogeneous one-dimensional systems in the asymptotic region. To investigate homogeneous as well as inhomogeneous systems, we use the density-matrix renormalization group (DMRG) method. We present results for ground state properties, such as the density-density correlation function and the parameter K{sub c}, which characterizes its decay at large distances. (orig.)
Power system dynamics and control
Kwatny, Harry G
2016-01-01
This monograph explores a consistent modeling and analytic framework that provides the tools for an improved understanding of the behavior and the building of efficient models of power systems. It covers the essential concepts for the study of static and dynamic network stability, reviews the structure and design of basic voltage and load-frequency regulators, and offers an introduction to power system optimal control with reliability constraints. A set of Mathematica tutorial notebooks providing detailed solutions of the examples worked-out in the text, as well as a package that will enable readers to work out their own examples and problems, supplements the text. A key premise of the book is that the design of successful control systems requires a deep understanding of the processes to be controlled; as such, the technical discussion begins with a concise review of the physical foundations of electricity and magnetism. This is followed by an overview of nonlinear circuits that include resistors, inductors, ...
Equilibration in one-dimensional quantum hydrodynamic systems
Sotiriadis, Spyros
2017-10-01
We study quench dynamics and equilibration in one-dimensional quantum hydrodynamics, which provides effective descriptions of the density and velocity fields in gapless quantum gases. We show that the information content of the large time steady state is inherently connected to the presence of ballistically moving localised excitations. When such excitations are present, the system retains memory of initial correlations up to infinite times, thus evading decoherence. We demonstrate this connection in the context of the Luttinger model, the simplest quantum hydrodynamic model, and in the quantum KdV equation. In the standard Luttinger model, memory of all initial correlations is preserved throughout the time evolution up to infinitely large times, as a result of the purely ballistic dynamics. However nonlinear dispersion or interactions, when separately present, lead to spreading and delocalisation that suppress the above effect by eliminating the memory of non-Gaussian correlations. We show that, for any initial state that satisfies sufficient clustering of correlations, the steady state is Gaussian in terms of the bosonised or fermionised fields in the dispersive or interacting case respectively. On the other hand, when dispersion and interaction are simultaneously present, a semiclassical approximation suggests that localisation is restored as the two effects compensate each other and solitary waves are formed. Solitary waves, or simply solitons, are experimentally observed in quantum gases and theoretically predicted based on semiclassical approaches, but the question of their stability at the quantum level remains to a large extent an open problem. We give a general overview on the subject and discuss the relevance of our findings to general out of equilibrium problems. Dedicated to John Cardy on the occasion of his 70th birthday.
Classification of Dynamic Vehicle Routing Systems
DEFF Research Database (Denmark)
Larsen, Allan; Madsen, Oli B.G.; Solomon, Marius M.
2007-01-01
This chapter discusses important characteristics seen within dynamic vehicle routing problems. We discuss the differences between the traditional static vehicle routing problems and its dynamic counterparts. We give an in-depth introduction to the degree of dynamism measure which can be used...... to classify dynamic vehicle routing systems. Methods for evaluation of the performance of algorithms that solve on-line routing problems are discussed and we list some of the most important issues to include in the system objective. Finally, we provide a three-echelon classification of dynamic vehicle routing...... systems based on their degree of dynamism and the system objective....
Momentum and spin dynamics of Dirac particles at effective dimensional reduction
Silenko, Alexander J.; Teryaev, Oleg V.
2012-11-01
We consider the dynamics of Dirac particles moving in the curved spaces of variable dimension interpolating smoothly between 3- and 2-dimensional spaces and considered as a toy model for 2-dimensional structures in solid state physics. Performing the Foldy-Wouthuysen (FW) transformation of Dirac equation and passing to the classical limit, we derive the equations of motion of momentum and spin. The spin precesses with the variable angular velocity and may "flick" appearing in the remnant 2-dimensional space twice during the period.
Hall conductivity for two dimensional magnetic systems
International Nuclear Information System (INIS)
Desbois, J.; Ouvry, S.; Texier, C.
1996-01-01
A Kubo inspired formalism is proposed to compute the longitudinal and transverse dynamical conductivities of an electron in a plane (or a gas of electrons at zero temperature) coupled to the potential vector of an external local magnetic field, with the additional coupling of the spin degree of freedom of the electron to the local magnetic field (Pauli Hamiltonian). As an example, the homogeneous magnetic field Hall conductivity is rederived. The case of the vortex at the origin is worked out in detail. A perturbative analysis is proposed for the conductivity in the random magnetic impurity problem (Poissonian vortices in the plane). (author)
On some dynamical chameleon systems
Burkin, I. M.; Kuznetsova, O. I.
2018-03-01
It is now well known that dynamical systems can be categorized into systems with self-excited attractors and systems with hidden attractors. A self-excited attractor has a basin of attraction that is associated with an unstable equilibrium, while a hidden attractor has a basin of attraction that does not intersect with small neighborhoods of any equilibrium points. Hidden attractors play the important role in engineering applications because they allow unexpected and potentially disastrous responses to perturbations in a structure like a bridge or an airplane wing. In addition, complex behaviors of chaotic systems have been applied in various areas from image watermarking, audio encryption scheme, asymmetric color pathological image encryption, chaotic masking communication to random number generator. Recently, researchers have discovered the so-called “chameleon systems”. These systems were so named because they demonstrate self-excited or hidden oscillations depending on the value of parameters. The present paper offers a simple algorithm of synthesizing one-parameter chameleon systems. The authors trace the evolution of Lyapunov exponents and the Kaplan-Yorke dimension of such systems which occur when parameters change.
Musashi dynamic image processing system
International Nuclear Information System (INIS)
Murata, Yutaka; Mochiki, Koh-ichi; Taguchi, Akira
1992-01-01
In order to produce transmitted neutron dynamic images using neutron radiography, a real time system called Musashi dynamic image processing system (MDIPS) was developed to collect, process, display and record image data. The block diagram of the MDIPS is shown. The system consists of a highly sensitive, high resolution TV camera driven by a custom-made scanner, a TV camera deflection controller for optimal scanning, which adjusts to the luminous intensity and the moving speed of an object, a real-time corrector to perform the real time correction of dark current, shading distortion and field intensity fluctuation, a real time filter for increasing the image signal to noise ratio, a video recording unit and a pseudocolor monitor to realize recording in commercially available products and monitoring by means of the CRTs in standard TV scanning, respectively. The TV camera and the TV camera deflection controller utilized for producing still images can be applied to this case. The block diagram of the real-time corrector is shown. Its performance is explained. Linear filters and ranked order filters were developed. (K.I.)
DEFF Research Database (Denmark)
Kumari Ramachandran, Gireesh Kumar Vasanta; Bredmose, Henrik; Sørensen, Jens Nørkær
2014-01-01
, which is a consequence of the wave-induced rotor dynamics. Loads and coupled responses are predicted for a set of load cases with different wave headings. Further, an advanced aero-elastic code, Flex5, is extended for the TLP wind turbine configuration and the response comparison with the simpler model......A dynamic model for a tension-leg platform (TLP) floating offshore wind turbine is proposed. The model includes three-dimensional wind and wave loads and the associated structural response. The total system is formulated using 17 degrees of freedom (DOF), 6 for the platform motions and 11...... for the wind turbine. Three-dimensional hydrodynamic loads have been formulated using a frequency-and direction-dependent spectrum. While wave loads are computed from the wave kinematics using Morison's equation, the aerodynamic loads are modeled by means of unsteady blade-element-momentum (BEM) theory...
Yonamine, Yusuke; Cervantes-Salguero, Keitel; Minami, Kosuke; Kawamata, Ibuki; Nakanishi, Waka; Hill, Jonathan P; Murata, Satoshi; Ariga, Katsuhiko
2016-05-14
In this study, a Langmuir-Blodgett (LB) system has been utilized for the regulation of polymerization of a DNA origami structure at the air-water interface as a two-dimensionally confined medium, which enables dynamic condensation of DNA origami units through variation of the film area at the macroscopic level (ca. 10-100 cm(2)). DNA origami sheets were conjugated with a cationic lipid (dioctadecyldimethylammonium bromide, 2C18N(+)) by electrostatic interaction and the corresponding LB-film was prepared. By applying dynamic pressure variation through compression-expansion processes, the lipid-modified DNA origami sheets underwent anisotropic polymerization forming a one-dimensionally assembled belt-shaped structure of a high aspect ratio although the thickness of the polymerized DNA origami was maintained at the unimolecular level. This approach opens up a new field of mechanical induction of the self-assembly of DNA origami structures.
Quantum Flexoelectricity in Low Dimensional Systems
Kalinin, Sergei V.; Meunien, Vincent
2007-01-01
Symmetry breaking at surfaces and interfaces and the capability to support large strain gradients in nanoscale systems enable new forms of electromechanical coupling. Here we introduce the concept of quantum flexoelectricity, a phenomenon that is manifested when the mechanical deformation of non-polar quantum systems results in the emergence of net dipole moments and hence linear electromechanical coupling proportional to local curvature. The concept is illustrated in carbon systems, includin...
Hyperbolicity, sinks and measure in one dimensional dynamics
Mañé, Ricardo
1985-12-01
Let f be a C 2 map of the circle or the interval and let Σ( f) denote the complement of the basins of attraction of the attracting periodic orbits. We prove that Σ( f) is a hyperbolic expanding set if (and obviously only if) every periodic point is hyperbolic and Σ( f) doesn't contain the critical point. This is the real one dimensional version of Fatou's hyperbolicity criteria for holomorphic endomorphisms of the Riemann sphere. We also explore other applications of the techniques used for the result above, proving, for instance, that for every C 2 immersion f of the circle (i.e. a map of the circle onto itself without critical points), either its Julia set has measure zero or it is the whole circle and then f is ergodic, i.e. positively invariant Borel sets have zero or full measure.
Fluid dynamics of two-dimensional pollination in Ruppia maritima
Musunuri, Naga; Bunker, Daniel; Pell, Susan; Pell, Fischer; Singh, Pushpendra
2016-11-01
The aim of this work is to understand the physics underlying the mechanisms of two-dimensional aquatic pollen dispersal, known as hydrophily. We observed two mechanisms by which the pollen released from male inflorescences of Ruppia maritima is adsorbed on a water surface: (i) inflorescences rise above the surface and after they mature their pollen mass falls onto the surface as clumps and disperses on the surface; (ii) inflorescences remain below the surface and produce air bubbles which carry their pollen mass to the surface where it disperses. In both cases dispersed pollen masses combined under the action of capillary forces to form pollen rafts. This increases the probability of pollination since the capillary force on a pollen raft towards a stigma is much larger than on a single pollen grain. The presence of a trace amount of surfactant can disrupt the pollination process so that the pollen is not transported or captured on the water surface. National Science Foundation.
The two-dimensional reactor dynamic program TINTE. Pt. 1
International Nuclear Information System (INIS)
Gerwin, H.
1987-11-01
The TINTE code deals with the nuclear and the thermal transient behaviour of an HTR taking into consideration the mutual feedback effects in two-dimensional r-z-geometry. Initial equations, approximations and solution procedures are compiled in this first part of the description. This involves the following subproblems: Time-dependent neutron flux calculation. Time-dependent heat source distribution (local and non-local fractions). Time-dependent heat transport from the fuel to the fuel element surface. Time-dependent global temperature distribution. Glas-flow even under natural circulation conditions for both a given total mass flow and a given pressure difference. Convection and its feedback to the circulation. The iterations of subproblem solutions, necessary because of the separate treatment, are discussed for both the transient case and of the determination of the steady initial state. (orig.) [de
Dynamical Properties of Two-Dimensional Josephson Junction Arrays
1990-05-01
current, i,0 , simply by Ic. = Mico , where M = 1000 is the number of junctions in parallel across the width of the array perpendicular to the current...identical junctions or some other form of disorder, the motion may be more complex , including effects such as vortex lattice shear. At higher temperatures...with the rf drive current as proposed in the vortex motion model. We have found interesting and complex dynamical behavior in the simulations that
Dynamic scaling of topological ordering in classical systems
Xu, Na; Castelnovo, Claudio; Melko, Roger G.; Chamon, Claudio; Sandvik, Anders W.
2018-01-01
We analyze scaling behaviors of simulated annealing carried out on various classical systems with topological order, obtained as appropriate limits of the toric code in two and three dimensions. We first consider the three-dimensional Z2 (Ising) lattice gauge model, which exhibits a continuous topological phase transition at finite temperature. We show that a generalized Kibble-Zurek scaling ansatz applies to this transition, in spite of the absence of a local order parameter. We find perimeter-law scaling of the magnitude of a nonlocal order parameter (defined using Wilson loops) and a dynamic exponent z =2.70 ±0.03 , the latter in good agreement with previous results for the equilibrium dynamics (autocorrelations). We then study systems where (topological) order forms only at zero temperature—the Ising chain, the two-dimensional Z2 gauge model, and a three-dimensional star model (another variant of the Z2 gauge model). In these systems the correlation length diverges exponentially, in a way that is nonsmooth as a finite-size system approaches the zero temperature state. We show that the Kibble-Zurek theory does not apply in any of these systems. Instead, the dynamics can be understood in terms of diffusion and annihilation of topological defects, which we use to formulate a scaling theory in good agreement with our simulation results. We also discuss the effect of open boundaries where defect annihilation competes with a faster process of evaporation at the surface.
The one-particle scenario for the metal-insulator transition in two-dimensional systems at T = 0
Tarasov, Y V
2003-01-01
The conductance of bounded disordered electron systems is calculated by reducing the original dynamic problem of arbitrary dimensionality to a set of strictly one-dimensional problems for one-particle mode propagators. The metallic ground state of a two-dimensional conductor, which is considered as a limiting case of three-dimensional quantum waveguide, is shown to result from its multi-modeness. As the waveguide thickness is reduced, e.g., by applying a 'pressing' potential, the electron system undergoes a set of continuous phase transitions related to discrete variations of the number of extended modes. The closing of the last current carrying mode is regarded as a phase transition of the electron system from metallic to dielectric state. The obtained results agree qualitatively with the observed 'anomalies' of resistivity of different two-dimensional electron and hole systems.
System dynamics for mechanical engineers
Davies, Matthew
2015-01-01
This textbook is ideal for mechanical engineering students preparing to enter the workforce during a time of rapidly accelerating technology, where they will be challenged to join interdisciplinary teams. It explains system dynamics using analogies familiar to the mechanical engineer while introducing new content in an intuitive fashion. The fundamentals provided in this book prepare the mechanical engineer to adapt to continuous technological advances with topics outside traditional mechanical engineering curricula by preparing them to apply basic principles and established approaches to new problems. This book also: · Reinforces the connection between the subject matter and engineering reality · Includes an instructor pack with the online publication that describes in-class experiments with minimal preparation requirements · Provides content dedicated to the modeling of modern interdisciplinary technological subjects, including opto-mechanical systems, high...
Dynamics of complex quantum systems
Akulin, Vladimir M
2014-01-01
This book gathers together a range of similar problems that can be encountered in different fields of modern quantum physics and that have common features with regard to multilevel quantum systems. The main motivation was to examine from a uniform standpoint various models and approaches that have been developed in atomic, molecular, condensed matter, chemical, laser and nuclear physics in various contexts. The book should help senior-level undergraduate, graduate students and researchers putting particular problems in these fields into a broader scientific context and thereby taking advantage of well-established techniques used in adjacent fields. This second edition has been expanded to include substantial new material (e.g. new sections on Dynamic Localization and on Euclidean Random Matrices and new chapters on Entanglement, Open Quantum Systems, and Coherence Protection). It is based on the author’s lectures at the Moscow Institute of Physics and Technology, at the CNRS Aimé Cotton Laboratory, and on ...
International Nuclear Information System (INIS)
Barrow, J.D.
1983-01-01
The role played by the dimensions of space and space-time in determining the form of various physical laws and constants of Nature is examined. Low dimensional manifolds are also seen to possess special mathematical properties. The concept of fractal dimension is introduced and the recent renaissance of Kaluza-Klein theories obtained by dimensional reduction from higher dimensional gravity or supergravity theories is discussed. A formulation of the anthropic principle is suggested. (author)
Quantum Flexoelectricity in Low Dimensional Systems
Energy Technology Data Exchange (ETDEWEB)
Kalinin, Sergei V [ORNL; Meunier, Vincent [ORNL
2008-01-01
Symmetry breaking at surfaces and interfaces and the capability to support large strain gradients in nanoscale systems enable new forms of electromechanical coupling. Here we introduce the concept of quantum flexoelectricity, a phenomenon that is manifested when the mechanical deformation of non-polar quantum systems results in the emergence of net dipole moments and hence linear electromechanical coupling proportional to local curvature. The concept is illustrated in carbon systems, including polyacetylene and nano graphitic ribbons. Using density functional theory calculations for systems made of up to 400 atoms, we determine the flexoelectric coefficients to be of the order of ~ 0.1 e, in agreement with the prediction of linear theory. The implications of quantum flexoelectricity on electromechanical device applications, and physics of carbon based materials are discussed.
Statistics of resonances in one-dimensional continuous systems
Indian Academy of Sciences (India)
dimensional continuous open system. The disordered system is semi-infinite, with white-noise random potential, and it is coupled to the external world by a semi-infinite continuous perfect lead. Our main result is an integral representation for the DOR ...
Lyapunov equation for infinite-dimensional discrete bilinear systems
International Nuclear Information System (INIS)
Costa, O.L.V.; Kubrusly, C.S.
1991-03-01
Mean-square stability for discrete systems requires that uniform convergence is preserved between input and state correlation sequences. Such a convergence preserving property holds for an infinite-dimensional bilinear system if and only if the associate Lyapunov equation has a unique strictly positive solution. (author)
Similarity reductions of the (2+1)-dimensional Burgers system
Liu, Dang-bo; Chu, Kai-qin
2001-08-01
In this paper, using the direct method of the (2+1)-dimensional multi-component Burgers system, some types of similarity reductions are obtained. The corresponding group explanations of the reductions, Virasoro integrability and soliton solutions of Burgers system are also discussed.
Three Dimensional Characterization of Quantum Vortex Dynamics in Superfluid Helium
Meichle, David; Lathrop, Daniel
2015-03-01
Vorticity is constrained to line-like topological defects in quantum superfluids, such as liquid Helium below the Lambda transition. We have invented a novel method to disperse fluorescent nanoparticles directly into the superfluid which become trapped on the vortex cores, providing optical tracers. Using a newly constructed multi-camera stereographic microscope, we present data dynamically characterizing vortex reconnections and the subsequent emission of Kelvin waves fully in three dimensions. Statistics of thermally driven counterflow will be compared in 3D to previous measurements in projection.
Krivov, Sergei V.
2011-07-01
Dimensionality reduction is ubiquitous in the analysis of complex dynamics. The conventional dimensionality reduction techniques, however, focus on reproducing the underlying configuration space, rather than the dynamics itself. The constructed low-dimensional space does not provide a complete and accurate description of the dynamics. Here I describe how to perform dimensionality reduction while preserving the essential properties of the dynamics. The approach is illustrated by analyzing the chess game—the archetype of complex dynamics. A variable that provides complete and accurate description of chess dynamics is constructed. The winning probability is predicted by describing the game as a random walk on the free-energy landscape associated with the variable. The approach suggests a possible way of obtaining a simple yet accurate description of many important complex phenomena. The analysis of the chess game shows that the approach can quantitatively describe the dynamics of processes where human decision-making plays a central role, e.g., financial and social dynamics.
Dynamical stability and low-temperature lattice specific heat of one-dimensional fullerene polymers
Shimizu, Atsushi; Ono, Shota
2018-02-01
We theoretically investigate the dynamical stability of one-dimensional fullerene polymers by computing the phonon dispersion relations within the atomistic approach. We find that only seven models among 54 models proposed previously (Noda et al., 2015) are dynamically stable. We show that the low temperature specific heat of them is proportional to the square root of the temperature in a wider range of temperature compared to the case of single-walled carbon nanotubes.
Dynamics of a two-dimensional discrete-time SIS model
Directory of Open Access Journals (Sweden)
Jaime H. Barrera
2012-04-01
Full Text Available We analyze a two-dimensional discrete-time SIS model with a non-constant total population. Our goal is to determine the interaction between the total population, the susceptible class and the infective class, and the implications this may have for the disease dynamics. Utilizing a constant recruitment rate in the susceptible class, it is possible to assume the existence of an asymptotic limiting equation, which enables us to reduce the system of, two-equations into a single, dynamically equivalent equation. In this case, we are able to demonstrate the global stability of the disease-free and the endemic equilibria when the basic reproductive number (Ro is less than one and greater than one, respectively. When we consider a non-constant recruitment rate, the total population bifurcates as we vary the birth rate and the death rate. Using computer simulations, we observe different behavior among the infective class and the total population, and possibly, the occurrence of a strange attractor.
Phase Diagram and Sweep Dynamics of a One-Dimensional Generalized Cluster Model
Ohta, Takumi; Tanaka, Shu; Danshita, Ippei; Totsuka, Keisuke
2015-06-01
We numerically study quantum phase transitions and dynamical properties in the one-dimensional cluster model with several interactions by using the time-evolving block decimation method for infinite systems and the exact diagonalization. First, boundaries among several quantum phases of the model are determined from energy gap and each phase is characterized by order parameters and the entanglement spectrum (ES). We confirm that in the model with open boundary condition the degeneracy of the lowest levels in the ES corresponds to that of the ground states. Then, using the time-dependent Bogoliubov transformation with open boundary condition, we investigate dynamical properties during an interaction sweep through the critical point which separates two topological phases involving four-fold degeneracy in the ground state. After a slow sweep across the critical point, we observe spatially periodic structures in the string correlation functions and the entanglement entropy. It is shown that the periodicities stem from the Bogoliubov quasiparticles generated near the critical point.
Internet-based dimensional verification system for reverse engineering processes
International Nuclear Information System (INIS)
Song, In Ho; Kim, Kyung Don; Chung, Sung Chong
2008-01-01
This paper proposes a design methodology for a Web-based collaborative system applicable to reverse engineering processes in a distributed environment. By using the developed system, design reviewers of new products are able to confirm geometric shapes, inspect dimensional information of products through measured point data, and exchange views with other design reviewers on the Web. In addition, it is applicable to verifying accuracy of production processes by manufacturing engineers. Functional requirements for designing this Web-based dimensional verification system are described in this paper. ActiveX-server architecture and OpenGL plug-in methods using ActiveX controls realize the proposed system. In the developed system, visualization and dimensional inspection of the measured point data are done directly on the Web: conversion of the point data into a CAD file or a VRML form is unnecessary. Dimensional verification results and design modification ideas are uploaded to markups and/or XML files during collaboration processes. Collaborators review the markup results created by others to produce a good design result on the Web. The use of XML files allows information sharing on the Web to be independent of the platform of the developed system. It is possible to diversify the information sharing capability among design collaborators. Validity and effectiveness of the developed system has been confirmed by case studies
Internet-based dimensional verification system for reverse engineering processes
Energy Technology Data Exchange (ETDEWEB)
Song, In Ho [Ajou University, Suwon (Korea, Republic of); Kim, Kyung Don [Small Business Corporation, Suwon (Korea, Republic of); Chung, Sung Chong [Hanyang University, Seoul (Korea, Republic of)
2008-07-15
This paper proposes a design methodology for a Web-based collaborative system applicable to reverse engineering processes in a distributed environment. By using the developed system, design reviewers of new products are able to confirm geometric shapes, inspect dimensional information of products through measured point data, and exchange views with other design reviewers on the Web. In addition, it is applicable to verifying accuracy of production processes by manufacturing engineers. Functional requirements for designing this Web-based dimensional verification system are described in this paper. ActiveX-server architecture and OpenGL plug-in methods using ActiveX controls realize the proposed system. In the developed system, visualization and dimensional inspection of the measured point data are done directly on the Web: conversion of the point data into a CAD file or a VRML form is unnecessary. Dimensional verification results and design modification ideas are uploaded to markups and/or XML files during collaboration processes. Collaborators review the markup results created by others to produce a good design result on the Web. The use of XML files allows information sharing on the Web to be independent of the platform of the developed system. It is possible to diversify the information sharing capability among design collaborators. Validity and effectiveness of the developed system has been confirmed by case studies
Melting in Two-Dimensional Lennard-Jones Systems: Observation of a Metastable Hexatic Phase
International Nuclear Information System (INIS)
Chen, K.; Kaplan, T.; Mostoller, M.
1995-01-01
Large scale molecular dynamics simulations of two-dimensional melting have been carried out using a recently revised Parrinello-Rahman scheme on massively parallel supercomputers. A metastable state is observed between the solid and liquid phases in Lennard-Jones systems of 36 864 and 102 400 atoms. This intermediate state shows the characteristics of the hexatic phase predicted by the theory of Kosterlitz, Thouless, Halperin, Nelson, and Young
Three-dimensional dynamic calculation in the low energy region of an electron linac
International Nuclear Information System (INIS)
Song Zhongheng; Wang Xiaomin
1990-09-01
The model of charge discs with variable radius and the model of charge rings are used in the three-dimensional dynamic calculation at the low energy region of an electron linac. The charged particles displacement, rate of displacement and trajectories are computed. The RMS emittance and pictures of beam emittance on different phase planes are also given
Three-dimensional simulations of ion dynamics in an Electron Cyclotron Resonance Ion Source
Beijers, J. P. M.; Mironov, V.
We present a three-dimensional simulation of the ion dynamics in an electron cyclotron resonance ion source. Ion trajectories in the min-B field of the source are calculated taking ion-ion and electron-ion collisions into account. The electrons are not tracked but considered as a neutralizing
International Nuclear Information System (INIS)
Brunie, L.
1992-12-01
The object of this thesis is to put in correspondence images coming from different ways. The area of application is biomedical imaging, particularly dynamic imaging in three dimensional calculations of spinal cord. The use of computers allows modeling. Then a study of validation by clinical experimentation on spinal cord proves the efficiency of the simulation
Jonathan P. Dandois; Erle C. Ellis
2013-01-01
High spatial resolution three-dimensional (3D) measurements of vegetation by remote sensing are advancing ecological research and environmental management. However, substantial economic and logistical costs limit this application, especially for observing phenological dynamics in ecosystem structure and spectral traits. Here we demonstrate a new aerial remote sensing...
DEFF Research Database (Denmark)
Hvam, Jørn Märcher; Langbein, Wolfgang; Borri, Paola
1999-01-01
Coherent optical spectroscopy in the form of nonlinear transient four-wave mixing (TFWM) and linear resonant Rayleigh scattering (RRS) has been applied to investigate the exciton dynamics of low-dimensional semiconductor heterostructures. The dephasing times of excitons are determined from...
Three-dimensional dynamic models of subducting plate-overriding plate-upper mantle interaction
Meyer, Clio; Schellart, W. P.
2013-01-01
We present fully dynamic generic three-dimensional laboratory models of progressive subduction with an overriding plate and a weak subduction zone interface. Overriding plate thickness (TOP) is varied systematically (in the range 0-2.5 cm scaling to 0-125 km) to investigate its effect on subduction
Dynamic Three-Dimensional Geometry of the Aortic Valve Apparatus-A Feasibility Study
Khamooshian, Arash; Amador, Yannis; Hai, Ting; Jeganathan, Jelliffe; Saraf, Maria; Mahmood, Eitezaz; Matyal, Robina; Khabbaz, Kamal R; Mariani, Massimo; Mahmood, Feroze
OBJECTIVE: To provide (1) an overview of the aortic valve (AV) apparatus anatomy and nomenclature, and (2) data regarding the normal AV apparatus geometry and dynamism during the cardiac cycle obtained from three-dimensional transesophageal echocardiography (3D TEE). DESIGN: Retrospective
Dynamical spin injection at a quasi-one-dimensional ferromagnet-graphene interface
International Nuclear Information System (INIS)
Singh, S.; Ahmadi, A.; Mucciolo, E. R.; Barco, E. del; Cherian, C. T.; Özyilmaz, B.
2015-01-01
We present a study of dynamical spin injection from a three-dimensional ferromagnet into two-dimensional single-layer graphene. Comparative ferromagnetic resonance (FMR) studies of ferromagnet/graphene strips buried underneath the central line of a coplanar waveguide show that the FMR linewidth broadening is the largest when the graphene layer protrudes laterally away from the ferromagnetic strip, indicating that the spin current is injected into the graphene areas away from the area directly underneath the ferromagnet being excited. Our results confirm that the observed damping is indeed a signature of dynamical spin injection, wherein a pure spin current is pumped into the single-layer graphene from the precessing magnetization of the ferromagnet. The observed spin pumping efficiency is difficult to reconcile with the expected backflow of spins according to the standard spin pumping theory and the characteristics of graphene, and constitutes an enigma for spin pumping in two-dimensional structures
On a high-dimensional objective genetic algorithm and its nonlinear dynamic properties
Huang, Jun; Huang, Xiaohong; Ma, Yan; Liu, Yanbing
2011-09-01
The revival of multi-objective optimization is mainly resulted from the recent development of multi-objective evolutionary optimization that allows the generation of the overall Pareto front. This paper presents an algorithm called HOGA (High-dimensional Objective Genetic Algorithm) for high-dimensional objective optimization on the basis of evolutionary computing. It adopts the principle of Shannon entropy to calculate the weight for each object since the well-known multi-objective evolutionary algorithms work poorly on the high-dimensional optimization problem. To further discuss the nonlinear dynamic property of HOGA, a martingale analysis approach is then employed; some mathematical derivations of the convergent theorems are obtained. The obtained results indicate that this new algorithm is indeed capable of achieving convergence and the suggested martingale analysis approach provides a new methodology for nonlinear dynamic analysis of evolutionary algorithms.
Few-Body Systems in Low-Dimensional Geometries
DEFF Research Database (Denmark)
Volosniev, Artem
2013-01-01
The research in this dissertation is devoted to few-body bound state physics in experimentally relevant systems of trapped atoms and molecules. First, the complexes of tubes containing dipoles are considered. The tubes are assumed to have zero width such that one-dimensional treatment can...... be applied. For this setup few-body bound structures are found for different polarization an- gles and dipole strengths by using stochastic variational methods. After that a similar analysis is provided for two-dimensional planes filled with dipolar par- ticles. At the end of the thesis, a system...
Bifurcation and chaos in simple jerk dynamical systems
Indian Academy of Sciences (India)
ical systems that can exhibit many major features of the regular and chaotic motion. In this paper, we ... models A to S) with three-dimensional vector fields that consist of five terms in- cluding two non-linearities or of six ..... of dynamics occur at the points (x, y) and (x, −y) in the parameter space (A, B). Very big regions (dark ...
Hamiltonian Analysis of 3-Dimensional Connection Dynamics in Bondi-like Coordinates
Huang, Chao-Guang; Kong, Shi-Bei
2017-08-01
The Hamiltonian analysis for a 3-dimensional connection dynamics of {s}{o}(1,2), spanned by {L‑+, L‑2, L+2 } instead of {L01, L02, L12 }, is first conducted in a Bondi-like coordinate system. The symmetry of the system is clearly presented. A null coframe with 3 independent variables and 9 connection coefficients are treated as basic configuration variables. All constraints and their consistency conditions, the solutions of Lagrange multipliers as well as the equations of motion are presented. There is no physical degree of freedom in the system. The Bañados–Teitelboim–Zanelli (BTZ) spacetime is discussed as an example to check the analysis. Unlike the ADM formalism, where only non-degenerate geometries on slices are dealt with and the Ashtekar formalism, where non-degenerate geometries on slices are mainly concerned though the degenerate geometries may be studied as well, in the present formalism the geometries on the slices are always degenerate though the geometries for the spacetime are not degenerate. Supported by National Natural Science Foundation of China under Grant Nos. 11275207 and 11690022
Neutron scattering studies of low dimensional magnetic systems
DEFF Research Database (Denmark)
Hansen, Ursula Bengård
CoCl2 · 2D2O have been investigated with neutron scattering experiments.CoCl2 · 2D2O can be considered a quasi one dimensional Ising system. This means, thatit is a near ideal model material for investigating low dimensional magnetic phenomena.The excitation spectrum of CoCl2 · 2D2O has been...... investigated at low temperaturesand in a longitudinal magnetic eld using neutron spectroscopy. Here we observe thehybridisation of the magnon bound states, inherent to the low dimensional nature ofCoCl2 · 2D2O.At higher temperature, signatures which can be attributed to Magnetic Bloch Oscillationsis observed......The results of this thesis can be divided into two parts, one concerning neutron scatteringstudies of low dimensional magnetic systems and one concerning neutron optics for theEuropean Spallation Source (ESS).In the part concerning low dimensional magnetic systems, three aspects of the dynamicsof...
A System Dynamic Model of Leader Emergence
2008-03-01
Judge, 2004; Judge, Bono, Ilies, & Gerhardt, 2002; Eagly, Johanneses-Schmidt, & Van Engen , 2003; Taggar, Hackett, & Saha, 1999; Stogdill, 1948...System dynamics emerged from the study of electrical control systems, and when generalized found many useful applications in natural systems outside...of the electrical world (Forrester, 1992). Whereas correlations describe cause and effect relationships in a linear equation, system dynamics
Approximating high-dimensional dynamics by barycentric coordinates with linear programming
Energy Technology Data Exchange (ETDEWEB)
Hirata, Yoshito, E-mail: yoshito@sat.t.u-tokyo.ac.jp; Aihara, Kazuyuki; Suzuki, Hideyuki [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Department of Mathematical Informatics, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan); CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Shiro, Masanori [Department of Mathematical Informatics, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan); Mathematical Neuroinformatics Group, Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan); Takahashi, Nozomu; Mas, Paloma [Center for Research in Agricultural Genomics (CRAG), Consorci CSIC-IRTA-UAB-UB, Barcelona 08193 (Spain)
2015-01-15
The increasing development of novel methods and techniques facilitates the measurement of high-dimensional time series but challenges our ability for accurate modeling and predictions. The use of a general mathematical model requires the inclusion of many parameters, which are difficult to be fitted for relatively short high-dimensional time series observed. Here, we propose a novel method to accurately model a high-dimensional time series. Our method extends the barycentric coordinates to high-dimensional phase space by employing linear programming, and allowing the approximation errors explicitly. The extension helps to produce free-running time-series predictions that preserve typical topological, dynamical, and/or geometric characteristics of the underlying attractors more accurately than the radial basis function model that is widely used. The method can be broadly applied, from helping to improve weather forecasting, to creating electronic instruments that sound more natural, and to comprehensively understanding complex biological data.
Dynamical systems of algebraic origin
Schmidt, Klaus
1995-01-01
Although much of classical ergodic theory is concerned with single transformations and one-parameter flows, the subject inherits from statistical mechanics not only its name, but also an obligation to analyze spatially extended systems with multidimensional symmetry groups. However, the wealth of concrete and natural examples which has contributed so much to the appeal and development of classical dynamics, is noticeably absent in this more general theory. The purpose of this book is to help remedy this scarcity of explicit examples by introducing a class of continuous Zd-actions diverse enough to exhibit many of the new phenomena encountered in the transition from Z to Zd, but which nevertheless lends itself to systematic study: the Zd-actions by automorphisms of compact, abelian groups. One aspect of these actions, not surprising in itself but quite striking in its extent and depth nonetheless, is the connection with commutative algebra and arithmetical algebraic geometry. The algebraic framework resulting...
Properties of interacting low-dimensional systems
Gumbs, Godfrey
2013-01-01
Filling the gap for comprehensive coverage of the realistic fundamentals and approaches needed to perform cutting-edge research on mesoscopic systems, this textbook allows advanced students to acquire and use the skills at a highly technical, research-qualifying level. Starting with a brief refresher to get all readers on an equal footing, the text moves on to a broad selection of advanced topics, backed by problems with solutions for use in classrooms as well as for self-study. Written by authors with research and teaching backgrounds from eminent institutions and based on a tried-and
Electron localization in one-dimensional systems
International Nuclear Information System (INIS)
Chao, K.A.
1984-01-01
The pure regional localization and the global localization have been investigated via the inverse participation ratio and te moment analysis. If the envelop function of a localized state is more complicated than the simple exponential function e sup(-r/xi), the inverse participation ratio is inadequate to describe the localization properties of an electron. This is the case discovered recently in a stereo-irregular chain fo atoms including the electron-electron interaction and the structure disorder. The localization properties in this system are analysed in terms of the moments. (Author) [pt
Exact solutions and conservation laws of the system of two-dimensional viscous Burgers equations
Abdulwahhab, Muhammad Alim
2016-10-01
Fluid turbulence is one of the phenomena that has been studied extensively for many decades. Due to its huge practical importance in fluid dynamics, various models have been developed to capture both the indispensable physical quality and the mathematical structure of turbulent fluid flow. Among the prominent equations used for gaining in-depth insight of fluid turbulence is the two-dimensional Burgers equations. Its solutions have been studied by researchers through various methods, most of which are numerical. Being a simplified form of the two-dimensional Navier-Stokes equations and its wide range of applicability in various fields of science and engineering, development of computationally efficient methods for the solution of the two-dimensional Burgers equations is still an active field of research. In this study, Lie symmetry method is used to perform detailed analysis on the system of two-dimensional Burgers equations. Optimal system of one-dimensional subalgebras up to conjugacy is derived and used to obtain distinct exact solutions. These solutions not only help in understanding the physical effects of the model problem but also, can serve as benchmarks for constructing algorithms and validation of numerical solutions of the system of Burgers equations under consideration at finite Reynolds numbers. Independent and nontrivial conserved vectors are also constructed.
Dynamical Signatures of Living Systems
Zak, M.
1999-01-01
One of the main challenges in modeling living systems is to distinguish a random walk of physical origin (for instance, Brownian motions) from those of biological origin and that will constitute the starting point of the proposed approach. As conjectured, the biological random walk must be nonlinear. Indeed, any stochastic Markov process can be described by linear Fokker-Planck equation (or its discretized version), only that type of process has been observed in the inanimate world. However, all such processes always converge to a stable (ergodic or periodic) state, i.e., to the states of a lower complexity and high entropy. At the same time, the evolution of living systems directed toward a higher level of complexity if complexity is associated with a number of structural variations. The simplest way to mimic such a tendency is to incorporate a nonlinearity into the random walk; then the probability evolution will attain the features of diffusion equation: the formation and dissipation of shock waves initiated by small shallow wave disturbances. As a result, the evolution never "dies:" it produces new different configurations which are accompanied by an increase or decrease of entropy (the decrease takes place during formation of shock waves, the increase-during their dissipation). In other words, the evolution can be directed "against the second law of thermodynamics" by forming patterns outside of equilibrium in the probability space. Due to that, a specie is not locked up in a certain pattern of behavior: it still can perform a variety of motions, and only the statistics of these motions is constrained by this pattern. It should be emphasized that such a "twist" is based upon the concept of reflection, i.e., the existence of the self-image (adopted from psychology). The model consists of a generator of stochastic processes which represents the motor dynamics in the form of nonlinear random walks, and a simulator of the nonlinear version of the diffusion
Development of MARS for multi-dimensional and multi-purpose thermal-hydraulic system analysis
International Nuclear Information System (INIS)
Lee, Won Jae; Chung, Bub Dong; Kim, Kyung Doo; Hwang, Moon Kyu; Jeong, Jae Jun; Ha, Kwi Seok; Joo, Han Gyu
2000-01-01
MARS (Multi-dimensional Analysis of Reactor Safety) code is being developed by KAERI for the realistic thermal-hydraulic simulation of light water reactor system transients. MARS 1.4 has been developed as a final version of basic code frame for the multi-dimensional analysis of system thermal-hydraulics. Since MARS 1.3, MARS 1.4 has been improved to have the enhanced code capability and user friendliness through the unification of input/output features, code models and code functions, and through the code modernization. Further improvements of thermal-hydraulic models, numerical method and user friendliness are being carried out for the enhanced code accuracy. As a multi-purpose safety analysis code system, a coupled analysis system, MARS/MASTER/CONTEMPT, has been developed using multiple DLL (Dynamic Link Library) techniques of Windows system. This code system enables the coupled, that is, more realistic analysis of multi-dimensional thermal-hydraulics (MARS 2.0), three-dimensional core kinetics (MASTER) and containment thermal-hydraulics (CONTEMPT). This paper discusses the MARS development program, and the developmental progress of the MARS 1.4 and the MARS/MASTER/CONTEMPT focusing on major features of the codes and their verification. It also discusses thermal hydraulic models and new code features under development. (author)
Development of MARS for multi-dimensional and multi-purpose thermal-hydraulic system analysis
Energy Technology Data Exchange (ETDEWEB)
Lee, Won Jae; Chung, Bub Dong; Kim, Kyung Doo; Hwang, Moon Kyu; Jeong, Jae Jun; Ha, Kwi Seok; Joo, Han Gyu [Korea Atomic Energy Research Institute, T/H Safety Research Team, Yusung, Daejeon (Korea)
2000-10-01
MARS (Multi-dimensional Analysis of Reactor Safety) code is being developed by KAERI for the realistic thermal-hydraulic simulation of light water reactor system transients. MARS 1.4 has been developed as a final version of basic code frame for the multi-dimensional analysis of system thermal-hydraulics. Since MARS 1.3, MARS 1.4 has been improved to have the enhanced code capability and user friendliness through the unification of input/output features, code models and code functions, and through the code modernization. Further improvements of thermal-hydraulic models, numerical method and user friendliness are being carried out for the enhanced code accuracy. As a multi-purpose safety analysis code system, a coupled analysis system, MARS/MASTER/CONTEMPT, has been developed using multiple DLL (Dynamic Link Library) techniques of Windows system. This code system enables the coupled, that is, more realistic analysis of multi-dimensional thermal-hydraulics (MARS 2.0), three-dimensional core kinetics (MASTER) and containment thermal-hydraulics (CONTEMPT). This paper discusses the MARS development program, and the developmental progress of the MARS 1.4 and the MARS/MASTER/CONTEMPT focusing on major features of the codes and their verification. It also discusses thermal hydraulic models and new code features under development. (author)
International Nuclear Information System (INIS)
Wang Qing; Hou Yu-Long; Jing Jian; Long Zheng-Wen
2014-01-01
In this paper, we study symmetrical properties of two-dimensional (2D) screened Dirac Hydrogen atom and isotropic harmonic oscillator with scalar and vector potentials of equal magnitude (SVPEM). We find that it is possible for both cases to preserve so(3) and su(2) dynamical symmetries provided certain conditions are satisfied. Interestingly, the conditions for preserving these dynamical symmetries are exactly the same as non-relativistic screened Hydrogen atom and screened isotropic oscillator preserving their dynamical symmetries. Some intuitive explanations are proposed. (general)
Three-Dimensional Dynamics of Baroclinic Tides Over a Seamount
Vlasenko, Vasiliy; Stashchuk, Nataliya; Nimmo-Smith, W. Alex M.
2018-02-01
The Massachusetts Institute of Technology general circulation model is used for the analysis of baroclinic tides over Anton Dohrn Seamount (ADS), in the North Atlantic. The model output is validated against in situ data collected during the 136th cruise of the RRS "James Cook" in May-June 2016. The observational data set includes velocity time series recorded at two moorings as well as temperature, salinity, and velocity profiles collected at 22 hydrological stations. Synthesis of observational and model data enabled the reconstruction of the details of baroclinic tidal dynamics over ADS. It was found that the baroclinic tidal waves are generated in the form of tidal beams radiating from the ADS periphery to its center, focusing tidal energy in a surface layer over the seamount's summit. This energy focusing enhances subsurface water mixing and the local generation of internal waves. The tidal beams interacting with the seasonal pycnocline generate short-scale internal waves radiating from the ADS center. An important ecological outcome from this study concerns the pattern of residual currents generated by tides. The rectified flows over ADS have the form of a pair of dipoles, cyclonic and anticyclonic eddies located at the seamount's periphery. These eddies are potentially an important factor in local larvae dispersion and their escape from ADS.
Miyazaki, Mikio; Kimiho, Chino; Katoh, Ryuhei; Arai, Hitoshi; Ogihara, Fumihiro; Oguchi, Yuichi; Morozumi, Tatsuo; Kon, Mayuko; Komatsu, Kotaro
2012-01-01
Three-dimensional dynamic geometry software has the power to enhance students' learning of spatial geometry. The purpose of this research is to clarify what potential using three-dimensional dynamic geometry software can offer us in terms of how to develop the spatial geometry curriculum in lower secondary schools. By focusing on the impacts the…
Dynamics of dissipative systems and computational physics
International Nuclear Information System (INIS)
Adam, Gh.; Scutaru, H.; Ixaru, L.; Adam, S.; Rizea, M.; Stefanescu, E.; Mihalache, D.; Mazilu, D.; Crasovan, L.
2002-01-01
During the first year of research activity in the frame of this project there have been investigated two main topics: I. Dynamics of systems of fermions in complex dissipative media; II. Solitons with topologic charge in dissipative systems. An essential problem of the quantum information systems is the controllability and observability of the quantum states, generally described by Lindblad's master equation with phenomenological coefficients. In its usual form, this equation describes a decay of the mean-values, but not necessarily the expected decaying transitions. The basic and very difficult problem of a dissipative quantum theory is to project the evolution of the total system (the system of interest + the environment) on the space of the system of interest. In this case, one obtains a quantum master equation where the system evolution is described by two terms: 1) a Hamiltonian term for the processes with energy conservation, and 2) a non-Hamiltonian term with coefficients depending on the dissipative coupling. That means that a master equation is based on some approximations enabling the replacement of the operators of the dissipative environment with average value coefficients. It is often assumed that the evolution operators of the dissipative system define a semigroup, not a group as in the case of an isolated system. In this framework, Lindblad obtained a quantum master equation in agreement with all the quantum-mechanical principles. However, the Lindblad master equation was unable to secure a correct description of the decaying states. To do that, one has to take into account the transition operators between the system eigenstates with appropriate coefficients. Within this investigation, we have obtained an equation obeying to this requirement, giving the ρ(t) time derivative in terms of creation-annihilation operators of the single-particle states |i>, and λ ij , representing the dissipative coefficients, the microscopic expressions of which are
Dynamical systems theory for the Gardner equation
Saha, Aparna; Talukdar, B.; Chatterjee, Supriya
2014-02-01
The Gardner equation ut+auux+bu2ux+μuxxx=0 is a generic mathematical model for weakly nonlinear and weakly dispersive wave propagation when the effects of higher-order nonlinearity become significant. Using the so-called traveling wave ansatz u (x,t)=φ(ξ), ξ =x-vt (where v is the velocity of the wave) we convert the (1+1)-dimensional partial differential equation to a second-order ordinary differential equation in ϕ with an arbitrary constant and treat the latter equation by the methods of the dynamical systems theory. With some special attention on the equilibrium points of the equation, we derive an analytical constraint for admissible values of the parameters a, b, and μ. From the Hamiltonian form of the system we confirm that, in addition to the usual bright soliton solution, the equation can be used to generate three different varieties of internal waves of which one is a dark soliton recently observed in water [A. Chabchoub et al., Phys. Rev. Lett. 110, 124101 (2013), 10.1103/PhysRevLett.110.124101].
Generic Bell inequalities for multipartite mulit-dimensional systems
International Nuclear Information System (INIS)
Son, W.; Lee, J.; Kim, M.S.
2005-01-01
Full text: We present generic Bell inequalities for multipartite multi-dimensional systems. They utilize the set of measurements, which are coincident with the generalized version of Greenberger, Horne and Zeilinger (GHZ) paradox. The inequalities that must be satisfied by any local realistic theories are violated by quantum mechanics for even-dimensional multipartite systems. It is also shown that the maximal violation of the inequality is obtained by the generalized GHZ state, which is true multi-body nonseparable state. As a special case for the multipartite two-dimensional systems, it can be shown that the inequality agrees with Bell-Mermin version of inequality. Large sets of variants are shown to naturally emerge from the generic Bell inequalities. We will discuss the particular variants of Bell inequalities that are violated for all the systems including odd-dimensional multipartite systems. Interestingly the variants can be reduced into the Clauser-Horne-Shimony-Holt (CHSH) inequality as well as Ardehali inequality. (author)
Hybrid nonnegative and computational dynamical systems
Directory of Open Access Journals (Sweden)
Wassim M. Haddad
2002-01-01
Full Text Available Nonnegative and Compartmental dynamical systems are governed by conservation laws and are comprised of homogeneous compartments which exchange variable nonnegative quantities of material via intercompartmental flow laws. These systems typically possess hierarchical (and possibly hybrid structures and are remarkably effective in capturing the phenomenological features of many biological and physiological dynamical systems. In this paper we develop several results on stability and dissipativity of hybrid nonnegative and Compartmental dynamical systems. Specifically, using linear Lyapunov functions we develop sufficient conditions for Lyapunov and asymptotic stability for hybrid nonnegative dynamical systems. In addition, using linear and nonlinear storage functions with linear hybrid supply rates we develop new notions of dissipativity theory for hybrid nonnegative dynamical systems. Finally, these results are used to develop general stability criteria for feedback interconnections of hybrid nonnegative dynamical systems.
Spontaneous jamming in one-dimensional systems
O'Loan, O. J.; Evans, M. R.; Cates, M. E.
1998-04-01
We study the phenomenon of jamming in driven diffusive systems. We introduce a simple microscopic model in which jamming of a conserved driven species is mediated by the presence of a non-conserved quantity, causing an effective long-range interaction of the driven species. We study the model analytically and numerically, providing strong evidence that jamming occurs; however, this proceeds via a strict phase transition (with spontaneous symmetry breaking) only in a prescribed limit. Outside this limit, the nearby transition (characterised by an essential singularity) induces sharp crossovers and transient coarsening phenomena. We discuss the relevance of the model to two physical situations: the clustering of buses, and the clogging of a suspension forced along a pipe.
Methodology for dimensional variation analysis of ITER integrated systems
Energy Technology Data Exchange (ETDEWEB)
Fuentes, F. Javier, E-mail: FranciscoJavier.Fuentes@iter.org [ITER Organization, Route de Vinon-sur-Verdon—CS 90046, 13067 St Paul-lez-Durance (France); Trouvé, Vincent [Assystem Engineering & Operation Services, rue J-M Jacquard CS 60117, 84120 Pertuis (France); Cordier, Jean-Jacques; Reich, Jens [ITER Organization, Route de Vinon-sur-Verdon—CS 90046, 13067 St Paul-lez-Durance (France)
2016-11-01
Highlights: • Tokamak dimensional management methodology, based on 3D variation analysis, is presented. • Dimensional Variation Model implementation workflow is described. • Methodology phases are described in detail. The application of this methodology to the tolerance analysis of ITER Vacuum Vessel is presented. • Dimensional studies are a valuable tool for the assessment of Tokamak PCR (Project Change Requests), DR (Deviation Requests) and NCR (Non-Conformance Reports). - Abstract: The ITER machine consists of a large number of complex systems highly integrated, with critical functional requirements and reduced design clearances to minimize the impact in cost and performances. Tolerances and assembly accuracies in critical areas could have a serious impact in the final performances, compromising the machine assembly and plasma operation. The management of tolerances allocated to part manufacture and assembly processes, as well as the control of potential deviations and early mitigation of non-compliances with the technical requirements, is a critical activity on the project life cycle. A 3D tolerance simulation analysis of ITER Tokamak machine has been developed based on 3DCS dedicated software. This integrated dimensional variation model is representative of Tokamak manufacturing functional tolerances and assembly processes, predicting accurate values for the amount of variation on critical areas. This paper describes the detailed methodology to implement and update the Tokamak Dimensional Variation Model. The model is managed at system level. The methodology phases are illustrated by its application to the Vacuum Vessel (VV), considering the status of maturity of VV dimensional variation model. The following topics are described in this paper: • Model description and constraints. • Model implementation workflow. • Management of input and output data. • Statistical analysis and risk assessment. The management of the integration studies based on
Methodology for dimensional variation analysis of ITER integrated systems
International Nuclear Information System (INIS)
Fuentes, F. Javier; Trouvé, Vincent; Cordier, Jean-Jacques; Reich, Jens
2016-01-01
Highlights: • Tokamak dimensional management methodology, based on 3D variation analysis, is presented. • Dimensional Variation Model implementation workflow is described. • Methodology phases are described in detail. The application of this methodology to the tolerance analysis of ITER Vacuum Vessel is presented. • Dimensional studies are a valuable tool for the assessment of Tokamak PCR (Project Change Requests), DR (Deviation Requests) and NCR (Non-Conformance Reports). - Abstract: The ITER machine consists of a large number of complex systems highly integrated, with critical functional requirements and reduced design clearances to minimize the impact in cost and performances. Tolerances and assembly accuracies in critical areas could have a serious impact in the final performances, compromising the machine assembly and plasma operation. The management of tolerances allocated to part manufacture and assembly processes, as well as the control of potential deviations and early mitigation of non-compliances with the technical requirements, is a critical activity on the project life cycle. A 3D tolerance simulation analysis of ITER Tokamak machine has been developed based on 3DCS dedicated software. This integrated dimensional variation model is representative of Tokamak manufacturing functional tolerances and assembly processes, predicting accurate values for the amount of variation on critical areas. This paper describes the detailed methodology to implement and update the Tokamak Dimensional Variation Model. The model is managed at system level. The methodology phases are illustrated by its application to the Vacuum Vessel (VV), considering the status of maturity of VV dimensional variation model. The following topics are described in this paper: • Model description and constraints. • Model implementation workflow. • Management of input and output data. • Statistical analysis and risk assessment. The management of the integration studies based on
Directory of Open Access Journals (Sweden)
Liu Bing
2014-10-01
Full Text Available Earthquake action is the main external factor which influences long-term safe operation of civil construction, especially of the high-rise building. Applying time-history method to simulate earthquake response process of civil construction foundation surrounding rock is an effective method for the anti-knock study of civil buildings. Therefore, this paper develops a civil building earthquake disaster three-dimensional dynamic finite element numerical simulation system. The system adopts the explicit central difference method. Strengthening characteristics of materials under high strain rate and damage characteristics of surrounding rock under the action of cyclic loading are considered. Then, dynamic constitutive model of rock mass suitable for civil building aseismic analysis is put forward. At the same time, through the earthquake disaster of time-history simulation of Shenzhen Children’s Palace, reliability and practicability of system program is verified in the analysis of practical engineering problems.
Construction of exact dynamical invariants of two-dimensional ...
Indian Academy of Sciences (India)
A general method is used for the construction of second constant of motion of fourth order in momenta using the complex coordinates ( z , z ¯ ) . A fourth-order potential equation is obtained whose solutions directly provide a large class of integrable systems. The potential equation is tested with an interesting example which ...
Visual exploration of 2D autonomous dynamical systems
Müller, Thomas; Sadlo, Filip
2015-05-01
In an introductory course on dynamical systems or Hamiltonian mechanics, vector field diagrams are a central tool to show a system’s qualitative behaviour in a certain domain. Because of their low sampling rates and the involved issues of vector normalization, these plots give only a coarse insight and are unable to convey the vector field behaviour at locations with high variation, in particular in the neighbourhood of critical points. Similarly, automatic generation of phase portraits based on traditional sampling cannot precisely capture separatrices or limit cylces. In this paper, we present ASysViewer, an application for the interactive visual exploration of two-dimensional autonomous dynamical systems, using line integral convolution techniques for visualization, and grid-based techniques to extract critical points and separatrices. ASysViewer is addressed to undergraduate students during their first course in dynamical systems or Hamiltonian mechanics.
Taha, Doaa; Mkhonta, S. K.; Elder, K. R.; Huang, Zhi-Feng
2017-06-01
Understanding and controlling the properties and dynamics of topological defects is a lasting challenge in the study of two-dimensional materials, and is crucial to achieve high-quality films required for technological applications. Here grain boundary structures, energies, and dynamics of binary two-dimensional materials are investigated through the development of a phase field crystal model that is parametrized to match the ordering, symmetry, energy, and length scales of hexagonal boron nitride. Our studies reveal some new dislocation core structures for various symmetrically and asymmetrically tilted grain boundaries, in addition to those obtained in previous experiments and first-principles calculations. We also identify a defect-mediated growth dynamics for inversion domains governed by the collective atomic migration and defect core transformation at grain boundaries and junctions, a process that is related to inversion symmetry breaking in binary lattice.
Lindner, Michael; Donner, Reik V
2017-03-01
We study the Lagrangian dynamics of passive tracers in a simple model of a driven two-dimensional vortex resembling real-world geophysical flow patterns. Using a discrete approximation of the system's transfer operator, we construct a directed network that describes the exchange of mass between distinct regions of the flow domain. By studying different measures characterizing flow network connectivity at different time-scales, we are able to identify the location of dynamically invariant structures and regions of maximum dispersion. Specifically, our approach allows us to delimit co-existing flow regimes with different dynamics. To validate our findings, we compare several network characteristics to the well-established finite-time Lyapunov exponents and apply a receiver operating characteristic analysis to identify network measures that are particularly useful for unveiling the skeleton of Lagrangian chaos.
Kawasaki, Takeshi; Tanaka, Hajime
2010-06-16
The physical understanding of glass transition remains a major challenge of physics and materials science. Among various glass-forming liquids, a colloidal liquid interacting with hard-core repulsion is now regarded as one of the most ideal model systems. Here we study the structure and dynamics of three-dimensional polydisperse colloidal liquids by Brownian dynamics simulations. We reveal that medium-range crystalline bond orientational order of the hexagonal close packed structure grows in size and lifetime with increasing packing fraction. We show that dynamic heterogeneity may be a direct consequence of this transient structural ordering, which suggests its origin is thermodynamic rather than kinetic. We also reveal that nucleation of crystals preferentially occurs in regions of high medium-range order, reflecting the low crystal-liquid interfacial energy there. These findings may shed new light not only on the fundamental nature of the glass transition, but also the mechanism of crystal nucleation.
Effect of Zealotry in High-dimensional Opinion Dynamics Models
2015-02-18
the several platforms for portable computing to choose from, such as Apple iPad, Amazon Kindle, and Samsung Galaxy Note. A third example is the choice...of operating system, such as Microsoft Windows, Apple MAC O/S, and Linux (which itself has many choices, such as Ubuntu, Fedora, and Mint). Note that...e.g., a Linux Ubuntu user also installing Microsoft Windows). However, some individuals are zealots (e.g., fiercely loyal Apple fans) who advocate a
Multi-dimensional virtual system introduced to enhance canonical sampling
Higo, Junichi; Kasahara, Kota; Nakamura, Haruki
2017-10-01
When an important process of a molecular system occurs via a combination of two or more rare events, which occur almost independently to one another, computational sampling for the important process is difficult. Here, to sample such a process effectively, we developed a new method, named the "multi-dimensional Virtual-system coupled Monte Carlo (multi-dimensional-VcMC)" method, where the system interacts with a virtual system expressed by two or more virtual coordinates. Each virtual coordinate controls sampling along a reaction coordinate. By setting multiple reaction coordinates to be related to the corresponding rare events, sampling of the important process can be enhanced. An advantage of multi-dimensional-VcMC is its simplicity: Namely, the conformation moves widely in the multi-dimensional reaction coordinate space without knowledge of canonical distribution functions of the system. To examine the effectiveness of the algorithm, we introduced a toy model where two molecules (receptor and its ligand) bind and unbind to each other. The receptor has a deep binding pocket, to which the ligand enters for binding. Furthermore, a gate is set at the entrance of the pocket, and the gate is usually closed. Thus, the molecular binding takes place via the two events: ligand approach to the pocket and gate opening. In two-dimensional (2D)-VcMC, the two molecules exhibited repeated binding and unbinding, and an equilibrated distribution was obtained as expected. A conventional canonical simulation, which was 200 times longer than 2D-VcMC, failed in sampling the binding/unbinding effectively. The current method is applicable to various biological systems.
Kondo effect in three-dimensional Dirac and Weyl systems
Mitchell, Andrew K.; Fritz, Lars
2015-01-01
Magnetic impurities in three-dimensional Dirac and Weyl systems are shown to exhibit a fascinatingly diverse range of Kondo physics, with distinctive experimental spectroscopic signatures. When the Fermi level is precisely at the Dirac point, Dirac semimetals are in fact unlikely candidates for a
Pareto optimality for nonlinear infinite dimensional control systems
Directory of Open Access Journals (Sweden)
Evgenios P. Avgerinos
1990-01-01
Full Text Available In this note we establish the existence of Pareto optimal solutions for nonlinear, infinite dimensional control systems with state dependent control constraints and an integral criterion taking values in a separable, reflexive Banach lattice. An example is also presented in detail. Our result extends earlier ones obtained by Cesari and Suryanarayana.
Wigner distributions for finite dimensional quantum systems: An ...
Indian Academy of Sciences (India)
2005-07-11
Jul 11, 2005 ... physics pp. 981–993. Wigner distributions for finite dimensional quantum systems: An algebraic approach. S CHATURVEDI1,∗, E ERCOLESSI2, G MARMO3, G MORANDI4, ... Abstract. We discuss questions pertaining to the definition of 'momentum', 'momentum space' ..... multiple of the parity operator.
Three-Dimensional Extension of a Digital Library Service System
Xiao, Long
2010-01-01
Purpose: The paper aims to provide an overall methodology and case study for the innovation and extension of a digital library, especially the service system. Design/methodology/approach: Based on the three-dimensional structure theory of the information service industry, this paper combines a comprehensive analysis with the practical experiences…
Three-dimensional computer models of electrospinning systems
Directory of Open Access Journals (Sweden)
Smółka Krzysztof
2017-12-01
Full Text Available Electrospinning is a very interesting method that allows the fabrication of continuous fibers with diameters down to a few nanometers. This paper presents an overview of electrospinning systems as well as their comparison using proposed three-dimensional parameterized numerical models. The presented solutions allow an analysis of the electric field distribution.
Three-dimensional computer models of electrospinning systems
Smółka, Krzysztof; Firych-Nowacka, Anna; Lefik, Marcin
2017-12-01
Electrospinning is a very interesting method that allows the fabrication of continuous fibers with diameters down to a few nanometers. This paper presents an overview of electrospinning systems as well as their comparison using proposed three-dimensional parameterized numerical models. The presented solutions allow an analysis of the electric field distribution.
Multipetal vortex structures in two-dimensional models of geophysical fluid dynamics and plasma
International Nuclear Information System (INIS)
Goncharov, V.P.; Pavlov, V.I.
2001-01-01
A new class of strongly nonlinear steadily rotating vortices is found. The Hamiltonian contour dynamics is proposed as a new approach for their study in some models of geophysical fluid dynamics and plasma. Using the Euler description as a starting point, we present a systematic procedure to reduce the two-dimensional dynamics of constant-vorticity and constant-density patches to the Hamiltonian dynamics of their contours for various parametrizations of the contour. The special Dirac procedure is used to eliminate the constraints arising in the Hamiltonian formulations with the Lagrangian parametrization of the contour. Numerical estimations illustrating the physical significance of the results and the range of model parameters where these results can be applicable are presented. Possible generalizations of the approach based on the application of the Hamiltonian contour dynamics to nonplanar and 3D flows are discussed
Robust dissipativity for uncertain impulsive dynamical systems
Directory of Open Access Journals (Sweden)
Liu Bin
2003-01-01
Full Text Available We discuss the robust dissipativity with respect to the quadratic supply rate for uncertain impulsive dynamical systems. By employing the Hamilton-Jacobi inequality approach, some sufficient conditions of robust dissipativity for this kind of system are established. Finally, we specialize the obtained results to the case of uncertain linear impulsive dynamical systems.
An Axiomatic Representation of System Dynamics
Baianu, I
2004-01-01
An axiomatic representation of system dynamics is introduced in terms of categories, functors, organismal supercategories, limits and colimits of diagrams. Specific examples are considered in Complex Systems Biology, such as ribosome biogenesis and Hormonal Control in human subjects. "Fuzzy" Relational Structures are also proposed for flexible representations of biological system dynamics and organization.
Anomalous transport in low-dimensional systems with correlated disorder
International Nuclear Information System (INIS)
Izrailev, F M; Makarov, N M
2005-01-01
We review recent results on the anomalous transport in one-dimensional and quasi-one-dimensional systems with bulk and surface disorder. Principal attention is paid to the role of long-range correlations in random potentials for the bulk scattering and in corrugated profiles for the surface scattering. It is shown that with the proper type of correlations one can construct such a disorder that results in a selective transport with given properties. Of particular interest is the possibility to arrange windows of a complete transparency (or reflection) with dependence on the wave number of incoming classical waves or electrons
Dynamic stabilization of regular linear systems
Weiss, G; Curtain, RF
We consider a general class of infinite-dimensional linear systems, called regular linear systems, for which convenient representations are known to exist both in time and in frequency domain, For this class of systems, we investigate the concepts of stabilizability and detectability, in particular,
Hybrid Dynamical Systems Modeling, Stability, and Robustness
Goebel, Rafal; Teel, Andrew R
2012-01-01
Hybrid dynamical systems exhibit continuous and instantaneous changes, having features of continuous-time and discrete-time dynamical systems. Filled with a wealth of examples to illustrate concepts, this book presents a complete theory of robust asymptotic stability for hybrid dynamical systems that is applicable to the design of hybrid control algorithms--algorithms that feature logic, timers, or combinations of digital and analog components. With the tools of modern mathematical analysis, Hybrid Dynamical Systems unifies and generalizes earlier developments in continuous-time and discret
Application of 3-dimensional CAD modeling system in nuclear plants
International Nuclear Information System (INIS)
Suwa, Minoru; Saito, Shunji; Nobuhiro, Minoru
1990-01-01
Until now, the preliminary work for mutual components in nuclear plant were readied by using plastic models. Recently with the development of computer graphic techniques, we can display the components on the graphics terminal, better than with use of plastic model and actual plants. The computer model can be handled, both telescopically and microscopically. A computer technique called 3-dimensional CAD modeling system was used as the preliminary work and design system. Through application of this system, database for nuclear plants was completed in arrangement step. The data can be used for piping design, stress analysis, shop production, testing and site construction, in all steps. In addition, the data can be used for various planning works, even after starting operation of plant. This paper describes the outline of the 3-dimensional CAD modeling system. (author)
EB1 and cytoplasmic dynein mediate protrusion dynamics for efficient 3-dimensional cell migration.
Jayatilaka, Hasini; Giri, Anjil; Karl, Michelle; Aifuwa, Ivie; Trenton, Nicholaus J; Phillip, Jude M; Khatau, Shyam; Wirtz, Denis
2018-03-01
Microtubules have long been implicated to play an integral role in metastatic disease, for which a critical step is the local invasion of tumor cells into the 3-dimensional (3D) collagen-rich stromal matrix. Here we show that cell migration of human cancer cells uses the dynamic formation of highly branched protrusions that are composed of a microtubule core surrounded by cortical actin, a cytoskeletal organization that is absent in cells on 2-dimensional (2D) substrates. Microtubule plus-end tracking protein End-binding 1 and motor protein dynein subunits light intermediate chain 2 and heavy chain 1, which do not regulate 2D migration, critically modulate 3D migration by affecting RhoA and thus regulate protrusion branching through differential assembly dynamics of microtubules. An important consequence of this observation is that the commonly used cancer drug paclitaxel is 100-fold more effective at blocking migration in a 3D matrix than on a 2D matrix. This work reveals the central role that microtubule dynamics plays in powering cell migration in a more pathologically relevant setting and suggests further testing of therapeutics targeting microtubules to mitigate migration.-Jayatilaka, H., Giri, A., Karl, M., Aifuwa, I., Trenton, N. J., Phillip, J. M., Khatau, S., Wirtz, D. EB1 and cytoplasmic dynein mediate protrusion dynamics for efficient 3-dimensional cell migration.
Attachment is a dynamic system
Directory of Open Access Journals (Sweden)
Zlatka Cugmas
2003-04-01
Full Text Available On the basis of the study of recent scientific literature about the development of attachment, the author answers the following questions: which are the postulates the theory of attachment has about the stability of the patterns of attachment, which level of stability in the patterns of attachment from infancy to adulthood these studies illuminate and which factors significantly influence the (instability of the patterns of attachment in time. The theory of attachment assumes that normal circumstances elicit stability. Changes, however, can be the result of important events influencing the sensitivity of the object of attachment. Agreement has not yet been reached regarding the percentage of stability in the patterns of attachment. There is more agreement regarding attachment in adulthood than that in childhood. The results depend on the size and characteristics of the subjects of the research, the measuring instruments, type of data analysis etc. The author concludes that attachment is a dynamic system influenced by significant changes in life (the cognitive development of the child, external care, parents' divorce, different stressful situations. As the influence of stressful events on the individual person' s quality of attachment is examined, it is necessary to consider also his/her temperamental characteristics, role of other people in their lives, etc.
Directory of Open Access Journals (Sweden)
V. A. Trudonoshin
2015-01-01
Full Text Available The article proposes a technique to develop mathematical models (MM of elements of the three-dimensional (3D mechanical systems for universal simulation software systems that allow us automatically generate the MM of a system based on MM elements and their connections. The technique is based on the MM of 3 D body. Linear and angular velocities are used as the main phase variables (unknown in the MM of the system, linear and angular movements are used as the additional ones, the latter being defined by the normalized quaternions that have computational advantages over turning angles.The paper has considered equations of dynamics, formulas of transition from the global coordinate system to the local one and vice versa. A spherical movable joint is presented as an example of the interaction element between the bodies. The paper shows the MM equivalent circuits of a body and a spherical joint. Such a representation, as the equivalent circuit, automatically enables us to obtain topological equations of the system. Various options to build equations of the joint and advices for their practical use are given.
Dissipative control for singular impulsive dynamical systems
Directory of Open Access Journals (Sweden)
Li Yang
2012-04-01
Full Text Available The aim of this work is to study the dissipative control problem for singular impulsive dynamical systems. We start by introducing the impulse to the singular systems, and give the definition of the dissipation for singular impulsive dynamical systems. Then we discuss the dissipation of singular impulsive dynamical systems, we obtain some sufficient and necessary conditions for dissipation of these systems by solving some linear matrix inequalities (LMIs. By using this method, we design a state feedback controller to make the closed-loop system dissipative. At last, we testify the feasibility of the method by a numerical example.
Three-Dimensional Magnetohydrodynamic Simulation of Slapper Initiation Systems
Energy Technology Data Exchange (ETDEWEB)
Christensen, J S; Hrousis, C A
2010-03-09
Although useful information can be gleaned from 2D and even 1D simulations of slapper type initiation systems, these systems are inherently three-dimensional and therefore require full 3D representation to model all relevant details. Further, such representation provides additional insight into optimizing the design of such devices from a first-principles perspective and can thereby reduce experimental costs. We discuss in this paper several ongoing efforts in modeling these systems, our pursuit of validation, and extension of these methods to other systems. Our results show the substantial dependence upon highly accurate global equations of state and resistivity models in these analyses.
Fully Coupled Three-Dimensional Dynamic Response of a TLP Floating Wind Turbine in Waves and Wind
DEFF Research Database (Denmark)
Ramachandran, Gireesh Kumar V.R.; Bredmose, Henrik; Sørensen, Jens Nørkær
2013-01-01
A dynamic model for a tension-leg platform (TLP) floating offshore wind turbine is proposed. The model includes threedimensional wind and wave loads and the associated structural response. The total system is formulated using 17 degrees of freedom (DOF), 6 for the platform motions and 11 for the ......A dynamic model for a tension-leg platform (TLP) floating offshore wind turbine is proposed. The model includes threedimensional wind and wave loads and the associated structural response. The total system is formulated using 17 degrees of freedom (DOF), 6 for the platform motions and 11...... for the wind turbine. Three-dimensional hydrodynamic loads have been formulated using a frequency- and direction-dependent spectrum. While wave loads are computed from the wave kinematics using Morison’s equation, aerodynamic loads are modelled by means of unsteady Blade-Element-Momentum (BEM) theory......, including Glauert correction for high values of axial induction factor, dynamic stall, dynamic wake and dynamic yaw. The aerodynamic model takes into account the wind shear and turbulence effects. For a representative geographic location, platform responses are obtained for a set of wind and wave climatic...
Electronic Structure of Low-Dimensional Carbon Π-Systems
DEFF Research Database (Denmark)
García Lastra, Juan Maria; Boukahil, Idris; Qiao, Ruimin
2016-01-01
X-ray absorption spectroscopy (XAS) is combined with density functional theory (DFT) to determine the orbitals of one- and two-dimensional carbon Π-systems (lycopene, beta-carotene, retinal, retinol, retinoic acid, coronene, triphenylene). Considerable fine structure is observed for the transitio......-bonded carbon structures with low-dimensional character, such as those used in molecular complexes for solar cells, confined graphene structures, and molecular wires.......X-ray absorption spectroscopy (XAS) is combined with density functional theory (DFT) to determine the orbitals of one- and two-dimensional carbon Π-systems (lycopene, beta-carotene, retinal, retinol, retinoic acid, coronene, triphenylene). Considerable fine structure is observed for the transition...... from the C is level to the lowest unoccupied molecular orbital (LUMO) and explained by DFT. The wave functions of the one-dimensional chain molecules display the node structure of a vibrating string. The XAS transition energy is decomposed into contributions from the C is core level, the Π* final state...
Modular transportation system with a three dimensional routeing
Directory of Open Access Journals (Sweden)
Löffler Christoph
2015-12-01
Full Text Available In intra-enterprise logistics and automation of manufacturing processes general a rising productivity by high flexibility is required. Existing transportation systems exclusively use two-dimensional track sections, because they can be served with standard drives. Because of these simple structures the transport speed is limited and thereby also the throughput. In this paper now a modular transportation system is presented which could reach higher speeds with a direct drive and the use of centrifugal force compensating curves. Simultaneously the system also can change the altitude. All this succeeds with the integration of three-dimensional track sections. Therefore a two piped guiding system with a long stator linear motor was designed. To combine the linear motor with the three dimensional track special stator elements were developed which allow a bending of the stator to follow the route course. The current work deals with the implementation of a mechanical passive switch, which is operated by the electromagnetic forces of the linear motor. So no additional mechanical actors or a separate electromagnetic system are necessary.
Fluid dynamics of moving fish in a two-dimensional multiparticle collision dynamics model
Reid, Daniel A. P.; Hildenbrandt, H.; Hemelrijk, C. K.; Padding, J.T.
2012-01-01
The fluid dynamics of animal locomotion, such as that of an undulating fish, are of great interest to both biologists and engineers. However, experimentally studying these fluid dynamics is difficult and time consuming. Model studies can be of great help because of their simpler and more detailed
Multibody system dynamics, robotics and control
Gerstmayr, Johannes
2013-01-01
The volume contains 19 contributions by international experts in the field of multibody system dynamics, robotics and control. The book aims to bridge the gap between the modeling of mechanical systems by means of multibody dynamics formulations and robotics. In the classical approach, a multibody dynamics model contains a very high level of detail, however, the application of such models to robotics or control is usually limited. The papers aim to connect the different scientific communities in multibody dynamics, robotics and control. Main topics are flexible multibody systems, humanoid robots, elastic robots, nonlinear control, optimal path planning, and identification.
Gao, Yuan; Haapasalo, Markus; Shen, Ya; Wu, Hongkun; Li, Bingdong; Ruse, N Dorin; Zhou, Xuedong
2009-09-01
Root canal irrigation plays an important role in the debridement and disinfection of the root canal system and is an integral part of root canal preparation procedures. The aim was to construct a three-dimensional computational fluid dynamics (CFD) model of root canal irrigation, with a suitable turbulence model, and validate it to provide a novel method for studying the root canal irrigation. A camcorder was used to record the effect of irrigation in the in vitro model. An exact replica of the geometry and the physical parameters of the in vitro irrigation model were used in CFD analysis, considering four turbulent models. The in vitro irrigation model was used as the reference for the evaluation of the CFD models. The result showed that CFD analysis based on a shear stress transport (SST) k-omega turbulence model was in close agreement with the in vitro irrigation model. The in vitro and CFD analyses showed that the irrigant in the curved canal flushes only up to a limited distance beyond the tip of the needle. The results of the CFD analysis also showed that laminar flow exists in the needle lumen and transit the transitional and turbulent flow around the side-vent outlet of the needle and needle tip. The results suggested that CFD based on a SST k-omega turbulence model has the potential to serve as a platform for the study of root canal irrigation.
Extending topological surgery to natural processes and dynamical systems.
Directory of Open Access Journals (Sweden)
Stathis Antoniou
Full Text Available Topological surgery is a mathematical technique used for creating new manifolds out of known ones. We observe that it occurs in natural phenomena where a sphere of dimension 0 or 1 is selected, forces are applied and the manifold in which they occur changes type. For example, 1-dimensional surgery happens during chromosomal crossover, DNA recombination and when cosmic magnetic lines reconnect, while 2-dimensional surgery happens in the formation of tornadoes, in the phenomenon of Falaco solitons, in drop coalescence and in the cell mitosis. Inspired by such phenomena, we introduce new theoretical concepts which enhance topological surgery with the observed forces and dynamics. To do this, we first extend the formal definition to a continuous process caused by local forces. Next, for modeling phenomena which do not happen on arcs or surfaces but are 2-dimensional or 3-dimensional, we fill in the interior space by defining the notion of solid topological surgery. We further introduce the notion of embedded surgery in S3 for modeling phenomena which involve more intrinsically the ambient space, such as the appearance of knotting in DNA and phenomena where the causes and effect of the process lies beyond the initial manifold, such as the formation of black holes. Finally, we connect these new theoretical concepts with a dynamical system and we present it as a model for both 2-dimensional 0-surgery and natural phenomena exhibiting a 'hole drilling' behavior. We hope that through this study, topology and dynamics of many natural phenomena, as well as topological surgery itself, will be better understood.
Automatic inspection system for dimensional measurements of the saw blade milling cutter
Directory of Open Access Journals (Sweden)
Yung-Cheng Wang
2010-10-01
Full Text Available The demand for measuring equipments of automatic optical inspection has grown rapidly, because of its benefits of promoted efficiency and higher precision. Instead of manual projection measurements, measurement performance and efficiency can be obviously enhanced by the image measurement system. In this investigation, digital image processing and geometrical measurement principles have been integrated to develop a dynamic measurement system for the dimensional measurements of a saw blade milling cutter. The repeatability of the measurement system has been analyzed and its accuracy has been verified by using commercial 3D image measurement system. The analysis results show that the dimensional precision of 25μm and the angular precision of 0.21° can be realized by the self-developed measurement system. Between the results of the developed system and reference standard system, there are 25μm deviation in dimensional measurement and 0.26° in angular measurement. That measuring performances can meet the industrial requirement and the higher measurement efficiency can be achieved.
Directory of Open Access Journals (Sweden)
V. Lucarini
2012-01-01
Full Text Available The understanding of the statistical properties and of the dynamics of multistable systems is gaining more and more importance in a vast variety of scientific fields. This is especially relevant for the investigation of the tipping points of complex systems. Sometimes, in order to understand the time series of given observables exhibiting bimodal distributions, simple one-dimensional Langevin models are fitted to reproduce the observed statistical properties, and used to investing-ate the projected dynamics of the observable. This is of great relevance for studying potential catastrophic changes in the properties of the underlying system or resonant behaviours like those related to stochastic resonance-like mechanisms. In this paper, we propose a framework for encasing this kind of studies, using simple box models of the oceanic circulation and choosing as observable the strength of the thermohaline circulation. We study the statistical properties of the transitions between the two modes of operation of the thermohaline circulation under symmetric boundary forcings and test their agreement with simplified one-dimensional phenomenological theories. We extend our analysis to include stochastic resonance-like amplification processes. We conclude that fitted one-dimensional Langevin models, when closely scrutinised, may result to be more ad-hoc than they seem, lacking robustness and/or well-posedness. They should be treated with care, more as an empiric descriptive tool than as methodology with predictive power.
Possibilities of identifying cyber attack in noisy space of n-dimensional abstract system
Jašek, Roman; Dvořák, Jiří; Janková, Martina; Sedláček, Michal
2016-06-01
This article briefly mentions some selected options of current concept for identifying cyber attacks from the perspective of the new cyberspace of real system. In the cyberspace, there is defined n-dimensional abstract system containing elements of the spatial arrangement of partial system elements such as micro-environment of cyber systems surrounded by other suitably arranged corresponding noise space. This space is also gradually supplemented by a new image of dynamic processes in a discreet environment, and corresponding again to n-dimensional expression of time space defining existence and also the prediction for expected cyber attacksin the noise space. Noises are seen here as useful and necessary for modern information and communication technologies (e.g. in processes of applied cryptography in ICT) and then the so-called useless noises designed for initial (necessary) filtering of this highly aggressive environment and in future expectedly offensive background in cyber war (e.g. the destruction of unmanned means of an electromagnetic pulse, or for destruction of new safety barriers created on principles of electrostatic field or on other principles of modern physics, etc.). The key to these new options is the expression of abstract systems based on the models of microelements of cyber systems and their hierarchical concept in structure of n-dimensional system in given cyberspace. The aim of this article is to highlight the possible systemic expression of cyberspace of abstract system and possible identification in time-spatial expression of real environment (on microelements of cyber systems and their surroundings with noise characteristics and time dimension in dynamic of microelements' own time and externaltime defined by real environment). The article was based on a partial task of faculty specific research.
Possibilities of identifying cyber attack in noisy space of n-dimensional abstract system
Energy Technology Data Exchange (ETDEWEB)
Jašek, Roman; Dvořák, Jiří; Janková, Martina; Sedláček, Michal [Tomas Bata University in Zlin Nad Stranemi 4511, 760 05 Zlin, Czech republic jasek@fai.utb.cz, dvorakj@aconte.cz, martina.jankova@email.cz, michal.sedlacek@email.cz (Czech Republic)
2016-06-08
This article briefly mentions some selected options of current concept for identifying cyber attacks from the perspective of the new cyberspace of real system. In the cyberspace, there is defined n-dimensional abstract system containing elements of the spatial arrangement of partial system elements such as micro-environment of cyber systems surrounded by other suitably arranged corresponding noise space. This space is also gradually supplemented by a new image of dynamic processes in a discreet environment, and corresponding again to n-dimensional expression of time space defining existence and also the prediction for expected cyber attacksin the noise space. Noises are seen here as useful and necessary for modern information and communication technologies (e.g. in processes of applied cryptography in ICT) and then the so-called useless noises designed for initial (necessary) filtering of this highly aggressive environment and in future expectedly offensive background in cyber war (e.g. the destruction of unmanned means of an electromagnetic pulse, or for destruction of new safety barriers created on principles of electrostatic field or on other principles of modern physics, etc.). The key to these new options is the expression of abstract systems based on the models of microelements of cyber systems and their hierarchical concept in structure of n-dimensional system in given cyberspace. The aim of this article is to highlight the possible systemic expression of cyberspace of abstract system and possible identification in time-spatial expression of real environment (on microelements of cyber systems and their surroundings with noise characteristics and time dimension in dynamic of microelements’ own time and externaltime defined by real environment). The article was based on a partial task of faculty specific research.
International Nuclear Information System (INIS)
Prentice, H. J.; Proud, W. G.
2006-01-01
A technique has been developed to determine experimentally the three-dimensional displacement field on the rear surface of a dynamically deforming plate. The technique combines speckle analysis with stereoscopy, using a modified angular-lens method: this incorporates split-frame photography and a simple method by which the effective lens separation can be adjusted and calibrated in situ. Whilst several analytical models exist to predict deformation in extended or semi-infinite targets, the non-trivial nature of the wave interactions complicates the generation and development of analytical models for targets of finite depth. By interrogating specimens experimentally to acquire three-dimensional strain data points, both analytical and numerical model predictions can be verified more rigorously. The technique is applied to the quasi-static deformation of a rubber sheet and dynamically to Mild Steel sheets of various thicknesses
Three-dimensional display and measurement of cardiac dynamic indexes from MR images
International Nuclear Information System (INIS)
Kono, M.; Matsuo, M.; Yamasaki, K.; Banno, T.; Toriwaki, J.; Yokoi, S.; Oshita, H.
1986-01-01
The cardiac dynamic index, to which such variables as cardiac output, ejection fraction, and wall motion contribute, is routinely determined using various modalities such as angiography, radionuclide imaging, US, and x-ray CT. Each of these modalities, however, has some disadvantages in regard to evaluating the cardiac dynamic index. The authors have obtained precise multidirectional projection images of the heart by means of computer graphics and reformatted data of cardiac MR images obtained with cardiac gating. The contiguous coronal MR images of the heart are made at an interimage distance of 5 mm. In each section, five or six cardiac images can be obtained, depending on the systolic or diastolic phase. These images are stored in a computer, and a three-dimensional display of the heart with biocular observation and with multiplex holograms is made possible with computer graphics. Three-dimensional measurement of the cardiac index is now being attempted, including cardiac output, ejection fraction, and wall motion
Nonautonomous dynamical systems in the life sciences
Pötzsche, Christian
2013-01-01
Nonautonomous dynamics describes the qualitative behavior of evolutionary differential and difference equations, whose right-hand side is explicitly time dependent. Over recent years, the theory of such systems has developed into a highly active field related to, yet recognizably distinct from that of classical autonomous dynamical systems. This development was motivated by problems of applied mathematics, in particular in the life sciences where genuinely nonautonomous systems abound. The purpose of this monograph is to indicate through selected, representative examples how often nonautonomous systems occur in the life sciences and to outline the new concepts and tools from the theory of nonautonomous dynamical systems that are now available for their investigation.
Dynamical entropy for infinite quantum systems
International Nuclear Information System (INIS)
Hudetz, T.
1990-01-01
We review the recent physical application of the so-called Connes-Narnhofer-Thirring entropy, which is the successful quantum mechanical generalization of the classical Kolmogorov-Sinai entropy and, by its very conception, is a dynamical entropy for infinite quantum systems. We thus comparingly review also the physical applications of the classical dynamical entropy for infinite classical systems. 41 refs. (Author)
Narcissistic group dynamics of multiparty systems
Schruijer, S.G.L.
2015-01-01
Purpose – This paper aims to introduce and illustrate the notion of narcissistic group dynamics. It is claimed that narcissism does not simply reside within individuals but can be characteristic of groups and social systems. In this case, the focus is on narcissistic dynamics in multiparty systems.
Trust dynamics in a large system implementation
DEFF Research Database (Denmark)
Schlichter, Bjarne Rerup; Rose, Jeremy
2013-01-01
outcomes, but largely ignored the dynamics of trust relations. Giddens, as part of his study of modernity, theorises trust dynamics in relation to abstract social systems, though without focusing on information systems. We use Giddens’ concepts to investigate evolving trust relationships in a longitudinal...
Trust Dynamics in a Large System Implementation
DEFF Research Database (Denmark)
Schlichter, Bjarne Rerup; Rose, Jeremy
2013-01-01
the dynamics of trust relations. Giddens, as part of his study of modernity, theorises trust dynamics in relation to abstract social systems, though without focusing on information systems. We use Gid-dens’ concepts to investigate evolving trust relationships in a longitudinal case analysis of a large...
Logical entropy of quantum dynamical systems
Directory of Open Access Journals (Sweden)
Ebrahimzadeh Abolfazl
2016-01-01
Full Text Available This paper introduces the concepts of logical entropy and conditional logical entropy of hnite partitions on a quantum logic. Some of their ergodic properties are presented. Also logical entropy of a quantum dynamical system is dehned and ergodic properties of dynamical systems on a quantum logic are investigated. Finally, the version of Kolmogorov-Sinai theorem is proved.
The dynamical systems approach to numerical integration
Wisdom, Jack
2018-03-01
The dynamical systems approach to numerical integration is reviewed and extended. The new method is compared to some alternative methods based on the Lie series approach. The test problem is the motion of the outer planets. The algorithms developed using the dynamical systems approach perform well.
System dynamics modelling of situation awareness
CSIR Research Space (South Africa)
Oosthuizen, R
2015-11-01
Full Text Available . The feedback loops and delays in the Command and Control system also contribute to the complex dynamic behavior. This paper will build on existing situation awareness models to develop a System Dynamics model to support a qualitative investigation through...
Signatures of chaos and non-integrability in two-dimensional gravity with dynamical boundary
Directory of Open Access Journals (Sweden)
Fitkevich Maxim
2016-01-01
Full Text Available We propose a model of two-dimensional dilaton gravity with a boundary. In the bulk our model coincides with the classically integrable CGHS model; the dynamical boundary cuts of the CGHS strong-coupling region. As a result, classical dynamics in our model reminds that in the spherically-symmetric gravity: wave packets of matter fields either reflect from the boundary or form black holes. We find large integrable sector of multisoliton solutions in this model. At the same time, we argue that the model is globally non-integrable because solutions at the verge of black hole formation display chaotic properties.
Static and dynamic epidemia on chains and trees with two- and three-dimensional loops
Ivanova, Kristinka
1998-04-01
The dynamic epidemic model considers the expansion of a cluster in a medium containing a fraction x of mobile particles that are pushed by a propagation front. This model is exactly solved here on two- and three-dimensional chains and a Bethe tree, which are all decorated with consecutive either hexagon or tetrahedron loops. The exact values for the percolation threshold xc and the critical exponents are calculated and compared to the static hindrance cases. The fraction of site candidates for particle trapping on a tree is the relevant parameter for the threshold value of such dynamic epidemics in high dimensions.
Low-dimensional approximations for Finite Element Models of mechanical systems
DEFF Research Database (Denmark)
Elmegaard, Michael; Starke, Jens; Schilder, Frank
2011-01-01
The present study is dedicated to the dimension reduction of high-dimensional FE models of mechanical systems in which low-dimensional behaviour is observable. A low-dimensional model of the such a FE model is constructed and the bifurcation diagram of the low-dimensional system is compared...
Three-dimensional computer aided design system for plant layout
International Nuclear Information System (INIS)
Yoshinaga, Toshiaki; Kiguchi, Takashi; Tokumasu, Shinji; Kumamoto, Kenjiro.
1986-01-01
The CAD system for three-dimensional plant layout planning, with which the layout of pipings, cable trays, air conditioning ducts and so on in nuclear power plants can be planned and designed effectively in a short period is reported. This system comprises the automatic routing system by storing the rich experience and know-how of designers in a computer as the knowledge, and deciding the layout automatically following the predetermined sequence by using these, the interactive layout system for reviewing the routing results from higher level and modifying to the optimum layout, the layout evaluation system for synthetically evaluating the layout from the viewpoint of the operability such as checkup and maintenance, and the data base system which enables these effective planning and design. In this report, the total constitution of this system and the technical features and effects of the individual subsystems are outlined. In this CAD system for three-dimensional plant layout planning, knowledge engineering, CAD/CAM, computer graphics and other latest technology were introduced, accordingly by applying this system to plant design, the design can be performed quickly, various case studies can be carried out at planning stage, and systematic and optimum layout planning becomes possible. (Kako, I.)
The static and dynamic screening of power loss of a two-dimensional electron gas
Bennett, C.; Balkan, N.; Tanatar, B.; Celik, H.; Cankurtaran, M.
1998-07-01
Experimental results concerning the well-width dependence of the acoustic-phonon-assisted energy relaxation of a two-dimensional electron gas in GaAs/Ga1 - xAlxAs quantum-well structures are compared with theoretical models that involve piezoelectric and deformation-potential scattering and the effects of static and dynamic screening of the electron-acoustic phonon interaction. It is shown that screening only slightly modifies the predictions of the approximate calculations.
Bias driven coherent carrier dynamics in a two-dimensional aperiodic potential
de Moura, F. A. B. F.; Viana, L. P.; Lyra, M. L.; Malyshev, Victor; Dominguez-Adame, F.
2008-01-01
We study the dynamics of an electron wave-packet in a two-dimensional square lattice with an aperiodic site potential in the presence of an external uniform electric field. The aperiodicity is described by epsilon(m) = V cos(pi alpha m(x)(nu x)) cos(pi alpha m(y)(nu y)) at lattice sites (m(x),m(y)),
Partial dynamical systems, fell bundles and applications
Exel, Ruy
2017-01-01
Partial dynamical systems, originally developed as a tool to study algebras of operators in Hilbert spaces, has recently become an important branch of algebra. Its most powerful results allow for understanding structural properties of algebras, both in the purely algebraic and in the C*-contexts, in terms of the dynamical properties of certain systems which are often hiding behind algebraic structures. The first indication that the study of an algebra using partial dynamical systems may be helpful is the presence of a grading. While the usual theory of graded algebras often requires gradings to be saturated, the theory of partial dynamical systems is especially well suited to treat nonsaturated graded algebras which are in fact the source of the notion of "partiality". One of the main results of the book states that every graded algebra satisfying suitable conditions may be reconstructed from a partial dynamical system via a process called the partial crossed product. Running in parallel with partial dynamica...
Dynamical systems on 2- and 3-manifolds
Grines, Viacheslav Z; Pochinka, Olga V
2016-01-01
This book provides an introduction to the topological classification of smooth structurally stable diffeomorphisms on closed orientable 2- and 3-manifolds.The topological classification is one of the main problems of the theory of dynamical systems and the results presented in this book are mostly for dynamical systems satisfying Smale's Axiom A. The main results on the topological classification of discrete dynamical systems are widely scattered among many papers and surveys. This book presents these results fluidly, systematically, and for the first time in one publication. Additionally, this book discusses the recent results on the topological classification of Axiom A diffeomorphisms focusing on the nontrivial effects of the dynamical systems on 2- and 3-manifolds. The classical methods and approaches which are considered to be promising for the further research are also discussed. < The reader needs to be familiar with the basic concepts of the qualitative theory of dynamical systems which are present...
Dynamics of vehicle-road coupled system
Yang, Shaopu; Li, Shaohua
2015-01-01
Vehicle dynamics and road dynamics are usually considered to be two largely independent subjects. In vehicle dynamics, road surface roughness is generally regarded as random excitation of the vehicle, while in road dynamics, the vehicle is generally regarded as a moving load acting on the pavement. This book suggests a new research concept to integrate the vehicle and the road system with the help of a tire model, and establishes a cross-subject research framework dubbed vehicle-pavement coupled system dynamics. In this context, the dynamics of the vehicle, road and the vehicle-road coupled system are investigated by means of theoretical analysis, numerical simulations and field tests. This book will be a valuable resource for university professors, graduate students and engineers majoring in automotive design, mechanical engineering, highway engineering and other related areas. Shaopu Yang is a professor and deputy president of Shijiazhuang Tiedao University, China; Liqun Chen is a professor at Shanghai Univ...
NONLINEAR DYNAMICAL SYSTEMS - Final report
Energy Technology Data Exchange (ETDEWEB)
Philip Holmes
2005-12-31
This document is the final report on the work completed on DE-FG02-95ER25238 since the start of the second renewal period: Jan 1, 2001. It supplements the annual reports submitted in 2001 and 2002. In the renewal proposal I envisaged work in three main areas: Analytical and topological tools for studying flows and maps Low dimensional models of fluid flow Models of animal locomotion and I describe the progess made on each project.
Linking PCA and time derivatives of dynamic systems
Stanimirovic, Olja; Hoefsloot, Huub C. J.; de Bokx, Pieter K.; Smilde, Age K.
2006-01-01
Low dimensional approximate descriptions of the high dimensional phase space of dynamic processes are very useful. Principal component analysis (PCA) is the most used technique to find the low dimensional subspace of interest. Here, it will be shown that mean centering of the process data across
Second invariant for two-dimensional classical super systems
Indian Academy of Sciences (India)
In §3, we obtain a set of coupled linear equations using graded bracket relation for the canonical conjugate variable where the existence of the second-order invariant for the super dynamical system under consideration is being as- sumed. A consistent solution of these equations yields the systems which are integrable.
Two-Dimensional Electron System in Electromagnetic Radiation Field
Lungu, Radu Paul; Manolescu, Andrei
We consider a two-dimensional electron gas in the presence of a monochromatic linear polarized electromagnetic field, within the Floquet formalism. The Floquet states have a simple relation with the energy eigenstates in the absence of the field. Therefore the single-particle and the two-particle Green functions of the many-body system with Coulomb interactions, in the radiation field, can be formally calculated by the standard diagrammatic techniques, as for the conservative system. We derive the elementary excitations of quasi-particle type, the plasma dispersion relation, and the ground state quasi-energy, and we relate them to the corresponding results for the conservative system.
Three-dimensional integrated CAE system applying computer graphic technique
International Nuclear Information System (INIS)
Kato, Toshisada; Tanaka, Kazuo; Akitomo, Norio; Obata, Tokayasu.
1991-01-01
A three-dimensional CAE system for nuclear power plant design is presented. This system utilizes high-speed computer graphic techniques for the plant design review, and an integrated engineering database for handling the large amount of nuclear power plant engineering data in a unified data format. Applying this system makes it possible to construct a nuclear power plant using only computer data from the basic design phase to the manufacturing phase, and it increases the productivity and reliability of the nuclear power plants. (author)
Dynamics of harmonically-confined systems: Some rigorous results
Energy Technology Data Exchange (ETDEWEB)
Wu, Zhigang, E-mail: zwu@physics.queensu.ca; Zaremba, Eugene, E-mail: zaremba@sparky.phy.queensu.ca
2014-03-15
In this paper we consider the dynamics of harmonically-confined atomic gases. We present various general results which are independent of particle statistics, interatomic interactions and dimensionality. Of particular interest is the response of the system to external perturbations which can be either static or dynamic in nature. We prove an extended Harmonic Potential Theorem which is useful in determining the damping of the centre of mass motion when the system is prepared initially in a highly nonequilibrium state. We also study the response of the gas to a dynamic external potential whose position is made to oscillate sinusoidally in a given direction. We show in this case that either the energy absorption rate or the centre of mass dynamics can serve as a probe of the optical conductivity of the system. -- Highlights: •We derive various rigorous results on the dynamics of harmonically-confined atomic gases. •We derive an extension of the Harmonic Potential Theorem. •We demonstrate the link between the energy absorption rate in a harmonically-confined system and the optical conductivity.
Negative differential Rashba effect in two-dimensional hole systems
Habib, B.; Tutuc, E.; Melinte, S.; Shayegan, M.; Wasserman, D.; Lyon, S. A.; Winkler, R.
2004-01-01
We demonstrate experimentally and theoretically that two-dimensional (2D) heavy hole systems in single heterostructures exhibit a \\emph{decrease} in spin-orbit interaction-induced spin splitting with an increase in perpendicular electric field. Using front and back gates, we measure the spin splitting as a function of applied electric field while keeping the density constant. Our results are in contrast to the more familiar case of 2D electrons where spin splitting increases with electric field.
Canard solutions of two-dimensional singularly perturbed systems
Energy Technology Data Exchange (ETDEWEB)
Chen Xianfeng [Department of Mathematics, Shanghai Jiao Tong University, Shanghai 200240 (China)]. E-mail: chenxf@sjtu.edu.cn; Yu Pei [Department of Mathematics, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Applied Mathematics, University of Western Ontario London, Ont., N6A 5B7 (Canada); Han Maoan [Department of Mathematics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang Weijiang [Department of Mathematics, Shanghai Jiao Tong University, Shanghai 200240 (China)
2005-02-01
In this paper, some new lemmas on asymptotic analysis are established. We apply an asymptotic method to study generalized two-dimensional singularly perturbed systems with one parameter, whose critical manifold has an m-22 th-order degenerate extreme point. Certain sufficient conditions are obtained for the existence of canard solutions, which are the extension and correction of some existing results. Finally, one numerical example is given.
An adaptive fuzzy neural network for MIMO system model approximation in high-dimensional spaces.
Chak, C K; Feng, G; Ma, J
1998-01-01
An adaptive fuzzy system implemented within the framework of neural network is proposed. The integration of the fuzzy system into a neural network enables the new fuzzy system to have learning and adaptive capabilities. The proposed fuzzy neural network can locate its rules and optimize its membership functions by competitive learning, Kalman filter algorithm and extended Kalman filter algorithms. A key feature of the new architecture is that a high dimensional fuzzy system can be implemented with fewer number of rules than the Takagi-Sugeno fuzzy systems. A number of simulations are presented to demonstrate the performance of the proposed system including modeling nonlinear function, operator's control of chemical plant, stock prices and bioreactor (multioutput dynamical system).
Transcribing the balanced scorecard into system dynamics
DEFF Research Database (Denmark)
Nielsen, Steen; Nielsen, Erland Hejn
2013-01-01
The purpose of this paper is to show how a System Dynamics Modelling approach can be integrated into the Balanced Scorecard (BSC) for a case company with special focus on the handling of causality in a dynamic perspective. The BSC model includes five perspectives and a number of financial and non-financial...... the cause-and-effect relationships of an integrated BSC model. Including dynamic aspects of BSCs into the discussion is only in its infancy, so the aim of our work is also to contribute to both scholars’ and practitioners’ general understanding of how such delayed dynamic effects propagate through system...
Dmitrović, Lana Horvat
2017-01-01
The main purpose of this article is to study box dimension of orbits near hyperbolic and nonhyperbolic fixed points of discrete dynamical systems in higher dimensions. We generalize the known results for one-dimensional systems, that is, the orbits near the hyperbolic fixed point in one-dimensional discrete dynamical system has the box dimension equal to zero and the orbits near nonhyperbolic fixed point has positive box dimension. In the process of studying box dimensions, we use the stable,...
Calculation of dynamic hydraulic forces in nuclear plant piping systems
International Nuclear Information System (INIS)
Choi, D.K.
1982-01-01
A computer code was developed as one of the tools needed for analysis of piping dynamic loading on nuclear power plant high energy piping systems, including reactor safety and relief value upstream and discharge piping systems. The code calculates the transient hydraulic data and dynamic forces within the one-dimensional system, caused by a pipe rupture or sudden value motion, using a fixed space and varying time grid-method of characteristics. Subcooled, superheated, homogeneous two-phase and transition flow regimes are considered. A non-equilibrium effect is also considered in computing the fluid specific volume and fluid local sonic velocity in the two-phase mixture. Various hydraulic components such as a spring loaded or power operated value, enlarger, orifice, pressurized tank, multiple pipe junction (tee), etc. are considered as boundary conditions. Comparisons of calculated results with available experimental data shows a good agreement. (Author)
Safety Analysis of Stochastic Dynamical Systems
DEFF Research Database (Denmark)
Sloth, Christoffer; Wisniewski, Rafael
2015-01-01
This paper presents a method for verifying the safety of a stochastic system. In particular, we show how to compute the largest set of initial conditions such that a given stochastic system is safe with probability p. To compute the set of initial conditions we rely on the moment method that via...... Haviland's theorem allows an infinite dimensional optimization problem on measures to be formulated as a polynomial optimization problem. Subsequently, the moment sequence is truncated (relaxed) to obtain a finite dimensional polynomial optimization problem. Finally, we provide an illustrative example...
Dynamics of the two-dimensional directed Ising model in the paramagnetic phase
Godrèche, C.; Pleimling, M.
2014-05-01
We consider the nonconserved dynamics of the Ising model on the two-dimensional square lattice, where each spin is influenced preferentially by its east and north neighbours. The single-spin flip rates are such that the stationary state is Gibbsian with respect to the usual ferromagnetic Ising Hamiltonian. We show the existence, in the paramagnetic phase, of a dynamical transition between two regimes of violation of the fluctuation-dissipation theorem in the nonequilibrium stationary state: a regime of weak violation where the stationary fluctuation-dissipation ratio is finite, when the asymmetry parameter is less than a threshold value, and a regime of strong violation where this ratio vanishes asymptotically above the threshold. This study suggests that this novel kind of dynamical transition in nonequilibrium stationary states, already found for the directed Ising chain and the spherical model with asymmetric dynamics, might be quite general. In contrast with the latter models, the equal-time correlation function for the two-dimensional directed Ising model depends on the asymmetry.
Stochastic Thermodynamics: A Dynamical Systems Approach
Directory of Open Access Journals (Sweden)
Tanmay Rajpurohit
2017-12-01
Full Text Available In this paper, we develop an energy-based, large-scale dynamical system model driven by Markov diffusion processes to present a unified framework for statistical thermodynamics predicated on a stochastic dynamical systems formalism. Specifically, using a stochastic state space formulation, we develop a nonlinear stochastic compartmental dynamical system model characterized by energy conservation laws that is consistent with statistical thermodynamic principles. In particular, we show that the difference between the average supplied system energy and the average stored system energy for our stochastic thermodynamic model is a martingale with respect to the system filtration. In addition, we show that the average stored system energy is equal to the mean energy that can be extracted from the system and the mean energy that can be delivered to the system in order to transfer it from a zero energy level to an arbitrary nonempty subset in the state space over a finite stopping time.
Miura, Kousei; Kadone, Hideki; Koda, Masao; Kumagai, Hiroshi; Nagashima, Katsuya; Fujii, Kengo; Noguchi, Hiroshi; Funayama, Toru; Abe, Tetsuya; Furuya, Takeo; Yamazaki, Masashi
2018-02-01
Dropped head syndrome (DHS) is a cervical kyphotic deformity caused by apparent weakness of the neck extensor muscles. We often encounter patients whose symptoms, including impaired forward vision and neck pain, deteriorate while walking. This is the first report of a case of dynamic spinal alignment change in a patient with DHS during walking using three-dimensional gait analysis. A 78-year-old Japanese woman complained of impaired forward vision and neck pain while walking. Her radiograph showed severe cervical kyphosis. C2-C7 SVA was +74 mm and C7-S1 SVA was -18.4 mm. The patient attempted to compensate to improve forward vision through lumbar hyperlordosis. We analyzed the gait motion of the patient by using three-dimensional (3D) motion and wireless surface electromyographic analysis systems to measure two systems synchronously. The patient walked continuously for as long as possible. We calculated dynamic SVA from the 3D motion analysis. Her head drop deformity gradually progressed and interfered with her forward vision while walking. Cervical SVA gradually increased from 75 to 85 mm. Thoracic SVA, Lumbar SVA and Whole spine SVA were initially decreased because of compensatory lumbar hyperlordosis, but ultimately increased, suggesting decompensation by the time she had finished walking. EMG activity of the bilateral trapezius muscles gradually reduced, which reflected the disturbance of maintaining her posture. Previous static evaluation could not prove the dynamic change of spinal alignment and EMG activity during walking. By introducing 3D gait analysis, we could evaluate dynamic spinal alignment of a patient with DHS. Copyright © 2017 Elsevier Ltd. All rights reserved.
Session 6: Dynamic Modeling and Systems Analysis
Csank, Jeffrey; Chapman, Jeffryes; May, Ryan
2013-01-01
These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators
Formal First Integrals of General Dynamical Systems
Directory of Open Access Journals (Sweden)
Jia Jiao
2016-01-01
Full Text Available The goal of this paper is trying to make a complete study on the integrability for general analytic nonlinear systems by first integrals. We will firstly give an exhaustive discussion on analytic planar systems. Then a class of higher dimensional systems with invariant manifolds will be considered; we will develop several criteria for existence of formal integrals and give some applications to illustrate our results at last.
On a Five-Dimensional Chaotic System Arising from Double-Diffusive Convection in a Fluid Layer
Directory of Open Access Journals (Sweden)
R. Idris
2013-01-01
Full Text Available A chaotic system arising from double-diffusive convection in a fluid layer is investigated in this paper based on the theory of dynamical systems. A five-dimensional model of chaotic system is obtained using the Galerkin truncated approximation. The results showed that the transition from steady convection to chaos via a Hopf bifurcation produced a limit cycle which may be associated with a homoclinic explosion at a slightly subcritical value of the Rayleigh number.
Second Sound in Systems of One-Dimensional Fermions
Matveev, K. A.; Andreev, A. V.
2017-12-01
We study sound in Galilean invariant systems of one-dimensional fermions. At low temperatures, we find a broad range of frequencies in which in addition to the waves of density there is a second sound corresponding to the ballistic propagation of heat in the system. The damping of the second sound mode is weak, provided the frequency is large compared to a relaxation rate that is exponentially small at low temperatures. At lower frequencies, the second sound mode is damped, and the propagation of heat is diffusive.
Generation of higher dimensional entangled states in quantum Rabi systems
Albarrán-Arriagada, F.; Alvarado Barrios, G.; Cárdenas-López, F. A.; Romero, G.; Retamal, J. C.
2017-05-01
We present protocols for the generation of high-dimensional entangled states of anharmonic oscillators by means of coherent manipulation of light-matter systems in the ultrastrong coupling regime. Our protocols consider a pair of ultrastrong coupled qubit-cavity systems, each coupled to an ancilla qubit, and combine classical pulses plus the selection rules imposed by the parity symmetry. We study the robustness of the entangling protocols under dissipative effects. This proposal may have applications within state-of-art circuit quantum electrodynamics.
Dynamical tunneling in systems with a mixed phase space
Energy Technology Data Exchange (ETDEWEB)
Loeck, Steffen
2010-04-22
Tunneling is one of the most prominent features of quantum mechanics. While the tunneling process in one-dimensional integrable systems is well understood, its quantitative prediction for systems with a mixed phase space is a long-standing open challenge. In such systems regions of regular and chaotic dynamics coexist in phase space, which are classically separated but quantum mechanically coupled by the process of dynamical tunneling. We derive a prediction of dynamical tunneling rates which describe the decay of states localized inside the regular region towards the so-called chaotic sea. This approach uses a fictitious integrable system which mimics the dynamics inside the regular domain and extends it into the chaotic region. Excellent agreement with numerical data is found for kicked systems, billiards, and optical microcavities, if nonlinear resonances are negligible. Semiclassically, however, such nonlinear resonance chains dominate the tunneling process. Hence, we combine our approach with an improved resonance-assisted tunneling theory and derive a unified prediction which is valid from the quantum to the semiclassical regime. We obtain results which show a drastically improved accuracy of several orders of magnitude compared to previous studies. (orig.)
Low-energy-state dynamics of entanglement for spin systems
International Nuclear Information System (INIS)
Jafari, R.
2010-01-01
We develop the ideas of the quantum renormalization group and quantum information by exploring the low-energy-state dynamics of entanglement resources of a system close to its quantum critical point. We demonstrate that low-energy-state dynamical quantities of one-dimensional magnetic systems can show a quantum phase transition point and show scaling behavior in the vicinity of the transition point. To present our idea, we study the evolution of two spin entanglements in the one-dimensional Ising model in the transverse field. The system is initialized as the so-called thermal ground state of the pure Ising model. We investigate the evolution of the generation of entanglement with increasing magnetic field. We obtain that the derivative of the time at which the entanglement reaches its maximum with respect to the transverse field diverges at the critical point and its scaling behaviors versus the size of the system are the same as the static ground-state entanglement of the system.
Fault diagnosis for dynamic power system
International Nuclear Information System (INIS)
Thabet, A.; Abdelkrim, M.N.; Boutayeb, M.; Didier, G.; Chniba, S.
2011-01-01
The fault diagnosis problem for dynamic power systems is treated, the nonlinear dynamic model based on a differential algebraic equations is transformed with reduced index to a simple dynamic model. Two nonlinear observers are used for generating the fault signals for comparison purposes, one of them being an extended Kalman estimator and the other a new extended kalman filter with moving horizon with a study of convergence based on the choice of matrix of covariance of the noises of system and measurements. The paper illustrates a simulation study applied on IEEE 3 buses test system.
SIAM conference on applications of dynamical systems
Energy Technology Data Exchange (ETDEWEB)
1992-01-01
A conference (Oct.15--19, 1992, Snowbird, Utah; sponsored by SIAM (Society for Industrial and Applied Mathematics) Activity Group on Dynamical Systems) was held that highlighted recent developments in applied dynamical systems. The main lectures and minisymposia covered theory about chaotic motion, applications in high energy physics and heart fibrillations, turbulent motion, Henon map and attractor, integrable problems in classical physics, pattern formation in chemical reactions, etc. The conference fostered an exchange between mathematicians working on theoretical issues of modern dynamical systems and applied scientists. This two-part document contains abstracts, conference program, and an author index.
Collective Dynamics of Nonlinear and Disordered Systems
Radons, G; Just, W
2005-01-01
Phase transitions in disordered systems and related dynamical phenomena are a topic of intrinsically high interest in theoretical and experimental physics. This book presents a unified view, adopting concepts from each of the disjoint fields of disordered systems and nonlinear dynamics. Special attention is paid to the glass transition, from both experimental and theoretical viewpoints, to modern concepts of pattern formation, and to the application of the concepts of dynamical systems for understanding equilibrium and nonequilibrium properties of fluids and solids. The content is accessible to graduate students, but will also be of benefit to specialists, since the presentation extends as far as the topics of ongoing research work.
Planar dynamical systems selected classical problems
Liu, Yirong; Huang, Wentao
2014-01-01
This book presents in an elementary way the recent significant developments in the qualitative theory of planar dynamical systems. The subjects are covered as follows: the studies of center and isochronous center problems, multiple Hopf bifurcations and local and global bifurcations of the equivariant planar vector fields which concern with Hilbert's 16th problem. This book is intended for graduate students, post-doctors and researchers in the area of theories and applications of dynamical systems. For all engineers who are interested the theory of dynamical systems, it is also a reasona
Dynamics of mechanical systems with variable mass
Belyaev, Alexander
2014-01-01
The book presents up-to-date and unifying formulations for treating dynamics of different types of mechanical systems with variable mass. The starting point is overview of the continuum mechanics relations of balance and jump for open systems from which extended Lagrange and Hamiltonian formulations are derived. Corresponding approaches are stated at the level of analytical mechanics with emphasis on systems with a position-dependent mass and at the level of structural mechanics. Special emphasis is laid upon axially moving structures like belts and chains, and on pipes with an axial flow of fluid. Constitutive relations in the dynamics of systems with variable mass are studied with particular reference to modeling of multi-component mixtures. The dynamics of machines with a variable mass are treated in detail and conservation laws and the stability of motion will be analyzed. Novel finite element formulations for open systems in coupled fluid and structural dynamics are presented.
DEFF Research Database (Denmark)
Christiansen, Peter Leth; Gaididei, Yuri Borisovich; Rasmussen, Kim
1996-01-01
The dynamics of two-dimensional discrete structures is studied in the framework of the generalized two-dimensional discrete nonlinear Schrodinger equation. The nonlinear coupling in the form of the Ablowitz-Ladik nonlinearity and point impurities is taken into account. The stability properties...
Stability of dynamical systems on the role of monotonic and non-monotonic Lyapunov functions
Michel, Anthony N; Liu, Derong
2015-01-01
The second edition of this textbook provides a single source for the analysis of system models represented by continuous-time and discrete-time, finite-dimensional and infinite-dimensional, and continuous and discontinuous dynamical systems. For these system models, it presents results which comprise the classical Lyapunov stability theory involving monotonic Lyapunov functions, as well as corresponding contemporary stability results involving non-monotonicLyapunov functions.Specific examples from several diverse areas are given to demonstrate the applicability of the developed theory to many important classes of systems, including digital control systems, nonlinear regulator systems, pulse-width-modulated feedback control systems, and artificial neural networks. The authors cover the following four general topics: - Representation and modeling of dynamical systems of the types described above - Presentation of Lyapunov and Lagrange stability theory for dynamical sy...
International Nuclear Information System (INIS)
Gauvrit, Jean-Yves; Oppenheim, Catherine; Naggara, Olivier; Trystram, Denis; Fredy, Daniel; Meder, Jean-Francois; Nataf, Francois; Roux, Francois-Xavier; Munier, Thierry; Pruvo, Jean-Pierre; Leclerc, Xavier
2006-01-01
We assessed the value of three-dimensional (3D) dynamic magnetic resonance angiography (MRA) for the follow-up of patients with radiosurgically treated cerebral arteriovenous malformations (AVMs). Fifty-four patients with cerebral AVMs treated by radiosurgery (RS) were monitored using conventional catheter angiography (CCA) and 3D dynamic MRA with sensitivity encoding based on the parallel imaging. Cerebral AVM was qualitatively classified by two radiologists into one of five categories in terms of residual nidus size and persistence of early draining vein (I, >6 cm; II, 3-6 cm; III, <3 cm; IV, isolated early draining vein; V, complete obliteration). 3D MRA findings showed a good agreement with CCA in 40 cases (κ=0.62). Of 23 nidus detected on CCA, 3D dynamic MRA showed 14 residual nidus. Of 28 occluded nidus on 3D dynamic MRA, 22 nidus were occluded on CCA. The sensitivity and specificity of 3D dynamic MRA for the detection of residual AVM were 81% and 100%. 3D dynamic MRA after RS may therefore be useful in association with MRI and can be repeated as long as opacification of the nidus or early venous drainage persists, one CCA remaining indispensable to affirm the complete occlusion at the end of follow-up. (orig.)
Mao, Haiqing; Driscoll, Sean J; Li, Jing-Sheng; Li, Guoan; Wood, Kirkham B; Cha, Thomas D
2015-01-01
Background Context Neuroforaminal stenosis is one of the key factors causing clinical symptoms in patients with cervical radiculopathy. Previous quantitative studies on the neuroforaminal dimensions have focused on measurements in a static position. Little is known about dimensional changes of the neuroforamen in the cervical spine during functional dynamic neck motion under physiological loading conditions. Purpose To investigate the in vivo dimensional changes of the neuroforamen in human cervical spine (C3-C7) during dynamic flexion-extension neck motion. Study Design A case-control study. Methods 10 asymptomatic subjects were recruited for this study. The cervical spine of each subject underwent magnetic resonance image (MRI) scanning for construction of three dimensional (3D) vertebrae models from C3 to C7. The cervical spine was then imaged using a dual fluoroscopic system while the subject performed a dynamic flexion-extension neck motion in a sitting position. The 3D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral motion. The dimensions (area, height and width) were measured for each cervical neuroforamen (C3/C4, C4/C5, C5/C6 and C6/C7) in the following functional positons: neutral positon, maximal flexion and maximal extension. Repeated measures ANOVA and post-hoc analysis were used to examine the differences between levels and positions. Results Compared with the neutral position, almost all dimensional parameters (area, height and width) of the sub-axial cervical neuroforamen decreased in extension and increased in flexion, except the neuroforaminal area at C5/C6 (P=0.07) and the neuroforaminal height at C6/C7 (P=0.05) remained relatively constant from neutral to extension. When comparisons of the overall change from extension to flexion were made between segments, the overall changes of the neuroforaminal area and height revealed no significant differences between segments, the width overall change of the upper
Dynamics of Large Systems of Nonlinearly Evolving Units
Lu, Zhixin
The dynamics of large systems of many nonlinearly evolving units is a general research area that has great importance for many areas in science and technology, including biology, computation by artificial neural networks, statistical mechanics, flocking in animal groups, the dynamics of coupled neurons in the brain, and many others. While universal principles and techniques are largely lacking in this broad area of research, there is still one particular phenomenon that seems to be broadly applicable. In particular, this is the idea of emergence, by which is meant macroscopic behaviors that "emerge" from a large system of many "smaller or simpler entities such that...large entities" [i.e., macroscopic behaviors] arise which "exhibit properties the smaller/simpler entities do not exhibit." In this thesis we investigate mechanisms and manifestations of emergence in four dynamical systems consisting many nonlinearly evolving units. These four systems are as follows. (a) We first study the motion of a large ensemble of many noninteracting particles in a slowly changing Hamiltonian system that undergoes a separatrix crossing. In such systems, we find that separatrix-crossing induces a counterintuitive effect. Specifically, numerical simulation of two sets of densely sprinkled initial conditions on two energy curves appears to suggest that the two energy curves, one originally enclosing the other, seemingly interchange their positions. This, however, is topologically forbidden. We resolve this paradox by introducing a numerical simulation method we call "robust" and study its consequences. (b) We next study the collective dynamics of oscillatory pacemaker neurons in Suprachiasmatic Nucleus (SCN), which, through synchrony, govern the circadian rhythm of mammals. We start from a high-dimensional description of the many coupled oscillatory neuronal units within the SCN. This description is based on a forced Kuramoto model. We then reduce the system dimensionality by using
Modelling floor heating systems using a validated two-dimensional ground coupled numerical model
DEFF Research Database (Denmark)
Weitzmann, Peter; Kragh, Jesper; Roots, Peter
2005-01-01
This paper presents a two-dimensional simulation model of the heat losses and tempera-tures in a slab on grade floor with floor heating which is able to dynamically model the floor heating system. The aim of this work is to be able to model, in detail, the influence from the floor construction...... the floor. This model can be used to design energy efficient houses with floor heating focusing on the heat loss through the floor construction and foundation. It is found that it is impor-tant to model the dynamics of the floor heating system to find the correct heat loss to the ground, and further......, that the foundation has a large impact on the energy consumption of buildings heated by floor heating. Consequently, this detail should be in focus when designing houses with floor heating....
Treatment of dynamical processes in two-dimensional models of the troposphere and stratosphere
International Nuclear Information System (INIS)
Wuebbles, D.J.
1980-07-01
The physical structure of the troposphere and stratosphere is the result of an intricate interplay among a large number of radiative, chemical, and dynamical processes. Because it is not possible to model the global environment in the laboratory, theoretical models must be relied on, subject to observational verification, to simulate atmospheric processes. Of particular concern in recent years has been the modeling of those processes affecting the structure of ozone and other trace species in the stratosphere and troposphere. Zonally averaged two-dimensional models with spatial resolution in the vertical and meridional directions can provide a much more realistic representation of tracer transport than one-dimensional models, yet are capable of the detailed representation of chemical and radiative processes contained in the one-dimensional models. The purpose of this study is to describe and analyze existing approaches to representing global atmospheric transport processes in two-dimensional models and to discuss possible alternatives to these approaches. A general description of the processes controlling the transport of trace constituents in the troposphere and stratosphere is given
Fogarty, Thomás; Usui, Ayaka; Busch, Thomas; Silva, Alessandro; Goold, John
2017-11-01
We investigate the dynamics of the rate function and of local observables after a quench in models which exhibit phase transitions between a superfluid and an insulator in their ground states. Zeros of the return probability, corresponding to singularities of the rate functions, have been suggested to indicate the emergence of dynamical criticality and we address the question of whether such zeros can be tied to the dynamics of physically relevant observables and hence order parameters in the systems. For this we first numerically analyze the dynamics of a hard-core boson gas in a one-dimensional waveguide when a quenched lattice potential is commensurate with the particle density. Such a system can undergo a pinning transition to an insulating state and we find non-analytic behavior in the evolution of the rate function which is indicative of dynamical phase transitions. In addition, we perform simulations of the time dependence of the momentum distribution and compare the periodicity of this collapse and revival cycle to that of the non-analyticities in the rate function: the two are found to be closely related only for deep quenches. We then confirm this observation by analytic calculations on a closely related discrete model of hard-core bosons in the presence of a staggered potential and find expressions for the rate function for the quenches. By extraction of the zeros of the survival amplitude we uncover a non-equilibrium timescale for the emergence of non-analyticities and discuss its relationship with the dynamics of the experimentally relevant parity operator.
Dynamic analysis of multibody system immersed in a fluid medium
International Nuclear Information System (INIS)
Wu, R.W.; Liu, L.K.; Levy, S.
1977-01-01
This paper is concerned primarily with the development and evaluation of an analysis method for the reponse prediction of immersed systems to seismic and other dynamic excitations. For immersed multibody systems, the hydrodynamic interaction causes coupled motion among the solid bodies. Also, under intense external excitations, impact between bodies may occur. The complex character of such systems inhibit the use of conventional analytical solutions in closed form. Therefore, approximate numerical schemes have been devised. For an incompressible, inviscid fluid, the hydrodynamic forces exerted by the fluid on solid bodies are determined to be linearly proportional to the acceleration of the vibrating solid bodies; i.e., the presence of the fluid only affects the inertia of the solid body system. A finite element computer program has been developed for computing this hydrodynamic (or added) mass effect. This program can be used to determine the hydrodynamic mass of a two-dimensional fluid field with solid bodies of arbitrary geometry. Triangular elements and linear pressure interpolation function are used to discretize the fluid region. The component element method is used to determine the dynamic response of the multibody system to externally applied mechanical loading or support excitation. The present analysis method for predicting the dynamic response of submerged multibody system is quite general and pertains to any number of solid bodies. However in this paper, its application is demonstrated only for 4 and 25 body systems. (Auth.)
Collision avoidance for multiple Lagrangian dynamical systems with gyroscopic forces
Directory of Open Access Journals (Sweden)
Lorenzo Sabattini
2017-01-01
Full Text Available This article introduces a novel methodology for dealing with collision avoidance for groups of mobile robots. In particular, full dynamics are considered, since each robot is modeled as a Lagrangian dynamical system moving in a three-dimensional environment. Gyroscopic forces are utilized for defining the collision avoidance control strategy: This kind of forces leads to avoiding collisions, without interfering with the convergence properties of the multi-robot system’s desired control law. Collision avoidance introduces, in fact, a perturbation on the nominal behavior of the system: We define a method for choosing the direction of the gyroscopic force in an optimal manner, in such a way that perturbation is minimized. Collision avoidance and convergence properties are analytically demonstrated, and simulation results are provided for validation purpose.
Constraint Embedding for Multibody System Dynamics
Jain, Abhinandan
2009-01-01
This paper describes a constraint embedding approach for the handling of local closure constraints in multibody system dynamics. The approach uses spatial operator techniques to eliminate local-loop constraints from the system and effectively convert the system into tree-topology systems. This approach allows the direct derivation of recursive O(N) techniques for solving the system dynamics and avoiding the expensive steps that would otherwise be required for handling the closedchain dynamics. The approach is very effective for systems where the constraints are confined to small-subgraphs within the system topology. The paper provides background on the spatial operator O(N) algorithms, the extensions for handling embedded constraints, and concludes with some examples of such constraints.
Understanding and Modeling Teams As Dynamical Systems
Directory of Open Access Journals (Sweden)
Jamie C. Gorman
2017-07-01
Full Text Available By its very nature, much of teamwork is distributed across, and not stored within, interdependent people working toward a common goal. In this light, we advocate a systems perspective on teamwork that is based on general coordination principles that are not limited to cognitive, motor, and physiological levels of explanation within the individual. In this article, we present a framework for understanding and modeling teams as dynamical systems and review our empirical findings on teams as dynamical systems. We proceed by (a considering the question of why study teams as dynamical systems, (b considering the meaning of dynamical systems concepts (attractors; perturbation; synchronization; fractals in the context of teams, (c describe empirical studies of team coordination dynamics at the perceptual-motor, cognitive-behavioral, and cognitive-neurophysiological levels of analysis, and (d consider the theoretical and practical implications of this approach, including new kinds of explanations of human performance and real-time analysis and performance modeling. Throughout our discussion of the topics we consider how to describe teamwork using equations and/or modeling techniques that describe the dynamics. Finally, we consider what dynamical equations and models do and do not tell us about human performance in teams and suggest future research directions in this area.
A vein display system based on three-dimensional reconstruction
Wang, Danting; Zhou, Ya; Hu, Xiaoming; Wu, Zhaoguo; Dai, Xiaobin
2014-10-01
Venipuncture is the most common way of all invasive medical procedures. A vein display system can make vein access easier by capturing the vein information and projecting a visible vein image onto the skin, which is correctly aligned with the subject's vein. The existing systems achieve correct alignment by the design of coaxial structure. Such a structure causes complex optical and mechanical design and big physical dimensions inevitably. In this paper, we design a stereovision- based vein display system, which consists of a pair of cameras, a DLP projector and a near-infrared light source. We recover the three-dimensional venous structure from image pair acquired from two near-infrared cameras. Then the vein image from the viewpoint of projector is generated from the three-dimensional venous structure and projected exactly onto skin by the DLP projector. Since the stereo cameras get the depth information of vessels, the system can make sure the alignment of projected veins and the real veins without a coaxial structure. The experiment results prove that we propose a feasible solution for a portable and low-cost vein display device.
Quantum dynamics of dynamically unstable, integrable few-mode systems
Mathew, Ranchu; Tiesinga, Eite
2017-04-01
Recently, quenches in isolated ultra-cold atomic quantum systems have become a subject of intense study. We consider quantum few-mode systems that are integrable in their classical mean-field limit and become dynamically unstable after a quench of a system parameter. Specifically, we study the cases of a Bose-Einstein condensate (BEC) in a double-well potential and of an antiferromagnetic F = 1 spinor BEC constrained to a single spatial mode. First, we study the time dynamics of a coherent state after the quench within the truncated Wigner approximation and find that due to phase-space mixing the systems relax to a steady state. Using action-angle formalism and guided by insights from the related pendulum system, we obtain analytical expressions for the time evolution of expectation values of observables and their long-time values. We also study the full quantum dynamics of the systems. Comparing their results with the TWA results, we find agreement in the long-time expectation value of the observables. The relaxation time scales, however, are different.
Solved problems in dynamical systems and control
Tenreiro-Machado, J; Valério, Duarte; Galhano, Alexandra M
2016-01-01
This book presents a collection of exercises on dynamical systems, modelling and control. Each topic covered includes a summary of the theoretical background, problems with solutions, and further exercises.
Patched Green's function techniques for two-dimensional systems
DEFF Research Database (Denmark)
Settnes, Mikkel; Power, Stephen; Lin, Jun
2015-01-01
We present a numerically efficient technique to evaluate the Green's function for extended two-dimensional systems without relying on periodic boundary conditions. Different regions of interest, or “patches,” are connected using self-energy terms which encode the information of the extended parts...... of the system. The calculation scheme uses a combination of analytic expressions for the Green's function of infinite pristine systems and an adaptive recursive Green's function technique for the patches. The method allows for an efficient calculation of both local electronic and transport properties, as well...... as the inclusion of multiple probes in arbitrary geometries embedded in extended samples. We apply the patched Green's function method to evaluate the local densities of states and transmission properties of graphene systems with two kinds of deviations from the pristine structure: bubbles and perforations...
Incoherent control and entanglement for two-dimensional coupled systems
International Nuclear Information System (INIS)
Romano, Raffaele; D'Alessandro, Domenico
2006-01-01
We investigate accessibility and controllability of a quantum system S coupled to a quantum probe P, both described by two-dimensional Hilbert spaces, under the hypothesis that the external control affects only P. In this context accessibility and controllability properties describe to what extent it is possible to drive the state of the system S by acting on P and using the interaction between the two systems. We give necessary and sufficient conditions for these properties and we discuss the relation with the entangling capability of the interaction between S and P. In particular, we show that controllability can be expressed in terms of the SWAP and √(SWAP) operators acting on the composite system
Schiek, Richard [Albuquerque, NM
2006-06-20
A method of generating two-dimensional masks from a three-dimensional model comprises providing a three-dimensional model representing a micro-electro-mechanical structure for manufacture and a description of process mask requirements, reducing the three-dimensional model to a topological description of unique cross sections, and selecting candidate masks from the unique cross sections and the cross section topology. The method further can comprise reconciling the candidate masks based on the process mask requirements description to produce two-dimensional process masks.
Inflationary α -attractor cosmology: A global dynamical systems perspective
Alho, Artur; Uggla, Claes
2017-04-01
We study flat Friedmann-Lemaître-Robertson-Walker α -attractor E- and T-models by introducing a dynamical systems framework that yields regularized unconstrained field equations on two-dimensional compact state spaces. This results in both illustrative figures and a complete description of the entire solution spaces of these models, including asymptotics. In particular, it is shown that observational viability, which requires a sufficient number of e -folds, is associated with a particular solution given by a one-dimensional center manifold of a past asymptotic de Sitter state, where the center manifold structure also explains why nearby solutions are attracted to this "inflationary attractor solution." A center manifold expansion yields a description of the inflationary regime with arbitrary analytic accuracy, where the slow-roll approximation asymptotically describes the tangency condition of the center manifold at the asymptotic de Sitter state.
Dynamical response of local magnons: single impurity limit in one dimensional magnets
International Nuclear Information System (INIS)
Koiller, B.; Rezende, S.M.
1979-11-01
The dynamic response of local magnon modes associated with a single impurity spin in one-dimensional ferro and antiferromagnetic insulators is studied theoretically with the use of a Green's function formulation solved exactly, by transfer matrix techniques, for zero temperature. The calculations are applied to the typical 1 - d ferromagnet CsNiF 3 and the antiferromagnet TMMC as functions of the impurity parameters in a way to allow the interpretation of possible future measurements of defect modes in these materials. The theory also explains qualitatively recent measurements in the three dimensional defect antiferromagnets FeF 2 : Mn 2+ , CoF 2 : Mn 2+ and FeF 2 : Co 2+ . (Author) [pt
Sommer, F; Hoffmann, T K; Mlynski, G; Reichert, M; Grossi, A-S; Kröger, R; Lindemann, J
2018-04-01
The human nose takes primary responsibility for preconditioning inhaled air. Numerous pathologies can affect the physiology of the nose. The beginnings of flow analyzes were carried out with three-dimensional casting models and differently colored liquids. Temperature and humidity could not be taken into account. Today, much more complex analyzes are possible using computational fluid dynamics (CFD), which are based on three-dimensional models generated from computed tomography (CT) or magnetic resonance imaging (MRI) datasets. Here, flow velocities, temperature, humidity, and pressure differences can be simulated and displayed in high-resolution videos as a function of multiple boundary conditions. The analysis of pathological changes or surgical interventions is thereby possible.
Zhou, Jianhui; Chang, Hao-Ran
2018-02-01
We present a unified derivation of the dynamical correlation functions including density-density, density-current and current-current, of three-dimensional Weyl/Dirac semimetals by use of the Passarino-Veltman reduction scheme at zero temperature. The generalized Kramers-Kronig relations with arbitrary order of subtraction are established to verify these correlation functions. Our results lead to the exact chiral magnetic conductivity and directly recover the previous ones in several limits. We also investigate the magnetic susceptibilities, the orbital magnetization, and briefly discuss the impact of electron interactions on these physical quantities within the random phase approximation. Our work could provide a starting point for the investigation of the nonlocal transport and optical properties due to the higher-order spatial dispersion in three-dimensional Weyl/Dirac semimetals.
Dynameomics: a multi-dimensional analysis-optimized database for dynamic protein data.
Kehl, Catherine; Simms, Andrew M; Toofanny, Rudesh D; Daggett, Valerie
2008-06-01
The Dynameomics project is our effort to characterize the native-state dynamics and folding/unfolding pathways of representatives of all known protein folds by way of molecular dynamics simulations, as described by Beck et al. (in Protein Eng. Des. Select., the first paper in this series). The data produced by these simulations are highly multidimensional in structure and multi-terabytes in size. Both of these features present significant challenges for storage, retrieval and analysis. For optimal data modeling and flexibility, we needed a platform that supported both multidimensional indices and hierarchical relationships between related types of data and that could be integrated within our data warehouse, as described in the accompanying paper directly preceding this one. For these reasons, we have chosen On-line Analytical Processing (OLAP), a multi-dimensional analysis optimized database, as an analytical platform for these data. OLAP is a mature technology in the financial sector, but it has not been used extensively for scientific analysis. Our project is further more unusual for its focus on the multidimensional and analytical capabilities of OLAP rather than its aggregation capacities. The dimensional data model and hierarchies are very flexible. The query language is concise for complex analysis and rapid data retrieval. OLAP shows great promise for the dynamic protein analysis for bioengineering and biomedical applications. In addition, OLAP may have similar potential for other scientific and engineering applications involving large and complex datasets.
Exponential Stability of Stochastic Nonlinear Dynamical Price System with Delay
Directory of Open Access Journals (Sweden)
Wenli Zhu
2013-01-01
Full Text Available Based on Lyapunov stability theory, Itô formula, stochastic analysis, and matrix theory, we study the exponential stability of the stochastic nonlinear dynamical price system. Using Taylor's theorem, the stochastic nonlinear system with delay is reduced to an n-dimensional semilinear stochastic differential equation with delay. Some sufficient conditions of exponential stability and corollaries for such price system are established by virtue of Lyapunov function. The time delay upper limit is solved by using our theoretical results when the system is exponentially stable. Our theoretical results show that if the classical price Rayleigh equation is exponentially stable, so is its perturbed system with delay provided that both the time delay and the intensity of perturbations are small enough. Two examples are presented to illustrate our results.
Generation of dark solitons and their instability dynamics in two-dimensional condensates
Verma, Gunjan; Rapol, Umakant D.; Nath, Rejish
2017-04-01
We analyze numerically the formation and the subsequent dynamics of two-dimensional matter wave dark solitons in a Thomas-Fermi rubidium condensate using various techniques. An initially imprinted sharp phase gradient leads to the dynamical formation of a stationary soliton as well as very shallow gray solitons, whereas a smooth gradient only creates gray solitons. The depth and hence, the velocity of the soliton is provided by the spatial width of the phase gradient, and it also strongly influences the snake-instability dynamics of the two-dimensional solitons. The vortex dipoles stemming from the unstable soliton exhibit rich dynamics. Notably, the annihilation of a vortex dipole via a transient dark lump or a vortexonium state, the exchange of vortices between either a pair of vortex dipoles or a vortex dipole and a single vortex, and so on. For sufficiently large width of the initial phase gradient, the solitons may decay directly into vortexoniums instead of vortex pairs, and also the decay rate is augmented. Later, we discuss alternative techniques to generate dark solitons, which involve a Gaussian potential barrier and time-dependent interactions, both linear and periodic. The properties of the solitons can be controlled by tuning the amplitude or the width of the potential barrier. In the linear case, the number of solitons and their depths are determined by the quench time of the interactions. For the periodic modulation, a transient soliton lattice emerges with its periodicity depending on the modulation frequency, through a wave number selection governed by the local Bogoliubov spectrum. Interestingly, for sufficiently low barrier potential, both Faraday pattern and soliton lattice coexist. The snake instability dynamics of the soliton lattice is characteristically modified if the Faraday pattern is present.
The Episodic Nature of Experience: A Dynamical Systems Analysis.
Sreekumar, Vishnu; Dennis, Simon; Doxas, Isidoros
2017-07-01
Context is an important construct in many domains of cognition, including learning, memory, and emotion. We used dynamical systems methods to demonstrate the episodic nature of experience by showing a natural separation between the scales over which within-context and between-context relationships operate. To do this, we represented an individual's emails extending over about 5 years in a high-dimensional semantic space and computed the dimensionalities of the subspaces occupied by these emails. Personal discourse has a two-scaled geometry with smaller within-context dimensionalities than between-context dimensionalities. Prior studies have shown that reading experience (Doxas, Dennis, & Oliver, 2010) and visual experience (Sreekumar, Dennis, Doxas, Zhuang, & Belkin, 2014) have a similar two-scaled structure. Furthermore, the recurrence plot of the emails revealed that experience is predictable and hierarchical, supporting the constructs of some influential theories of memory. The results demonstrate that experience is not scale-free and provide an important target for accounts of how experience shapes cognition. Copyright © 2016 Cognitive Science Society, Inc.
International Nuclear Information System (INIS)
Rouet, J.L.; Feix, M.R.
1996-01-01
The test particle picture is a central theory of weakly correlated plasma. While experiments and computer experiments have confirmed the validity of this theory at thermal equilibrium, the extension to meta-equilibrium distributions presents interesting and intriguing points connected to the under or over-population of the tail of these distributions (high velocity) which have not yet been tested. Moreover, the general dynamical Debye cloud (which is a generalization of the static Debye cloud supposing a plasma at thermal equilibrium and a test particle of zero velocity) for any test particle velocity and three typical velocity distributions (equilibrium plus two meta-equilibriums) are presented. The simulations deal with a one-dimensional two-component plasma and, moreover, the relevance of the check for real three-dimensional plasma is outlined. Two kinds of results are presented: the dynamical cloud itself and the more usual density (or energy) fluctuation spectrums. Special attention is paid to the behavior of long wavelengths which needs long systems with very small graininess effects and, consequently, sizable computation efforts. Finally, the divergence or absence of energy in the small wave numbers connected to the excess or lack of fast particles of the two above mentioned meta-equilibrium is exhibited. copyright 1996 American Institute of Physics
Dynamic Double Curvature Mould System
DEFF Research Database (Denmark)
Jepsen, Christian Raun; Kristensen, Mathias Kræmmergaard; Kirkegaard, Poul Henning
2011-01-01
The present paper describes a concept for a reconfigurable mould surface which is designed to fit the needs of contemporary architecture. The core of the concept presented is a dynamic surface manipulated into a given shape using a digital signal created directly from the CAD drawing of the design....... This happens fast, automatic and without production of waste, and the manipulated surface is fair and robust, eliminating the need for additional, manual treatment. Limitations to the possibilities of the flexible form are limited curvature and limited level of detail, making it especially suited for larger...
Dynamics and control of technical systems
Balthazar, José M; Kaczmarczyk, Stefan
2014-01-01
The main topics of this Special Issue are linear and, mainly, nonlinear dynamics, chaos and control of systems and structures and their applications in different field of science and engineering. According to the goal of the Special Issue, the selected contributions are divided into three major parts: ""Vibration Problems in Vertical Transportation Systems"", ""Nonlinear Dynamics, Chaos and Control of Elastic Structures"" and ""New Strategies and Challenges for Aerospace and Ocean Structures Dynamics and Control"". The discussion of real problems in aerospace and how these problems can be unde
Dynamical systems examples of complex behaviour
Jost, Jürgen
2005-01-01
Our aim is to introduce, explain, and discuss the fundamental problems, ideas, concepts, results, and methods of the theory of dynamical systems and to show how they can be used in speci?c examples. We do not intend to give a comprehensive overview of the present state of research in the theory of dynamical systems, nor a detailed historical account of its development. We try to explain the important results, often neglecting technical re?nements 1 and, usually, we do not provide proofs. One of the basic questions in studying dynamical systems, i.e. systems that evolve in time, is the construction of invariants that allow us to classify qualitative types of dynamical evolution, to distinguish between qualitatively di?erent dynamics, and to studytransitions between di?erent types. Itis also important to ?nd out when a certain dynamic behavior is stable under small perturbations, as well as to understand the various scenarios of instability. Finally, an essential aspect of a dynamic evolution is the transformat...
Dynamic Modeling of Solar Dynamic Components and Systems
Hochstein, John I.; Korakianitis, T.
1992-01-01
The purpose of this grant was to support NASA in modeling efforts to predict the transient dynamic and thermodynamic response of the space station solar dynamic power generation system. In order to meet the initial schedule requirement of providing results in time to support installation of the system as part of the initial phase of space station, early efforts were executed with alacrity and often in parallel. Initially, methods to predict the transient response of a Rankine as well as a Brayton cycle were developed. Review of preliminary design concepts led NASA to select a regenerative gas-turbine cycle using a helium-xenon mixture as the working fluid and, from that point forward, the modeling effort focused exclusively on that system. Although initial project planning called for a three year period of performance, revised NASA schedules moved system installation to later and later phases of station deployment. Eventually, NASA selected to halt development of the solar dynamic power generation system for space station and to reduce support for this project to two-thirds of the original level.
Violating Bell inequalities maximally for two d-dimensional systems
International Nuclear Information System (INIS)
Chen Jingling; Wu Chunfeng; Oh, C. H.; Kwek, L. C.; Ge Molin
2006-01-01
We show the maximal violation of Bell inequalities for two d-dimensional systems by using the method of the Bell operator. The maximal violation corresponds to the maximal eigenvalue of the Bell operator matrix. The eigenvectors corresponding to these eigenvalues are described by asymmetric entangled states. We estimate the maximum value of the eigenvalue for large dimension. A family of elegant entangled states |Ψ> app that violate Bell inequality more strongly than the maximally entangled state but are somewhat close to these eigenvectors is presented. These approximate states can potentially be useful for quantum cryptography as well as many other important fields of quantum information
Renormalization-group study of one-dimensional quasiperiodic systems
Niu, Qian; Nori, Franco
1986-10-01
We report a new approach to the study of electron spectral clustering and wave-function scaling in several one-dimensional quasiperiodic systems. The approach is based on renormalization-group ideas. We introduce a novel decimation technique which generates a simple physical picture of the electronic spectral behavior and the nature of the wave functions. Our renormalization-group scheme is verified by the numerical computation of the probability density summed over the states belonging to the clusters and subclusters of the spectrum.
Pattern formation in two-dimensional square-shoulder systems
International Nuclear Information System (INIS)
Fornleitner, Julia; Kahl, Gerhard
2010-01-01
Using a highly efficient and reliable optimization tool that is based on ideas of genetic algorithms, we have systematically studied the pattern formation of the two-dimensional square-shoulder system. An overwhelming wealth of complex ordered equilibrium structures emerge from this investigation as we vary the shoulder width. With increasing pressure three structural archetypes could be identified: cluster lattices, where clusters of particles occupy the sites of distorted hexagonal lattices, lane formation, and compact particle arrangements with high coordination numbers. The internal complexity of these structures increases with increasing shoulder width.
Charged particles transport in one-dimensional finite systems
International Nuclear Information System (INIS)
Muthukrishnan, G.; Santhanam, K.; Gopinath, D.V.
1977-01-01
A semi-analytical technique for the charged particle transport in one-dimensional finite media is developed which can be applied to multi-energy multi-region systems with arbitrary degree of anisotropy in scattering. For this purpose the transport equation is cast in the form of coupled integral equations separating spatial and energy-angle transmission. The spatial transmission is evaluated using discrete ordinate representation in space, energy and direction cosine for the particle source and flux. The collision integral is evaluated using discrete ordinate representation in energy and legendre polynomial approximation in the direction cosine. A computer code based on the above formulation is described
Directory of Open Access Journals (Sweden)
Zhi-Ping Zeng
Full Text Available Abstract A three-dimensional rail-bridge coupling element of unequal lengths in which the length of the rail element is shorter than that of the bridge element is presented in this paper to investigate the spatial dynamic responses of a train-track-bridge interaction system. Formulation of stiffness and damping matrices for the fastener, ballast, and bearing, as well as the three-dimensional equations of motion in matrix form for a train-track-bridge interaction system using the proposed element are derived in detail using the energy principle. The accuracy of the proposed three-dimensional rail-bridge coupling element is verified using the existing two-dimensional element. Three examples of a seven-span continuous beam bridge are shown: the first investigates the influence of the efficiency and accuracy of the lengths of the rail and bridge elements on the spatial dynamic responses of the train-track-bridge interaction system, and the other two illustrate the influence of two types of track models and two types of wheel-rail interaction models on the dynamic responses of the system. Results show that (1 the proposed rail-bridge coupling element is not only able to help conserve calculation time, but it also gives satisfactory results when investigating the spatial dynamic responses of a train-track-bridge interaction system; (2 the double-layer track model is more accurate in comparison with the single-layer track model, particularly in relation to vibrations of bridge and rail; and (3 the no-jump wheel-rail interaction model is generally reliable and efficient in predicting the dynamic responses of a train-track-bridge interaction system.
Non-equilibrium coherence dynamics in one-dimensional Bose gases
DEFF Research Database (Denmark)
Hofferberth, S.; Lesanovsky, Igor; Fischer, B.
2007-01-01
, it remains a challenge to probe the dynamics by which this equilibrium state is reached. Here we present a direct experimental study of the coherence dynamics in both isolated and coupled degenerate 1D Bose gases. Dynamic splitting is used to create two 1D systems in a phase coherent state. The time...... evolution of the coherence is revealed through local phase shifts of the subsequently observed interference patterns. Completely isolated 1D Bose gases are observed to exhibit universal sub-exponential coherence decay, in excellent agreement with recent predictions. For two coupled 1D Bose gases...... range of physical systems, such as superconductors, quantum Hall systems, superfluid helium and spin systems. Our experiments studying coherence dynamics show that 1D Bose gases are ideally suited for investigating this class of phenomena....
Dynamics and bifurcations of a three-dimensional piecewise-linear integrable map
International Nuclear Information System (INIS)
Tuwankotta, J M; Quispel, G R W; Tamizhmani, K M
2004-01-01
In this paper, we consider a four-parameter family of piecewise-linear ordinary difference equations (OΔEs) in R 3 . This system is obtained as a limit of another family of three-dimensional integrable systems of OΔEs. We prove that the limiting procedure sends integrals of the original system to integrals of the limiting system. We derive some results for the solutions such as boundedness of solutions and the existence of periodic solutions. We describe all topologically different shapes of the integral manifolds and present all possible scenarios of transitions as we vary the natural parameters in the system, i.e. the values of the integrals
Introduction to Chaotic Dynamical Systems
1992-12-01
differential equations to first order systems see Borrelli - Coleman (Ref. 2]. 4 The general form of a linear system of differential equations is x,’ at...pendulum. The process of finding the ex- plicit solution to this system of differential equations is described in Borrelli - Coleman [Ref. 2]. 9 0...independent eigenvectors. The details can be found in Borrelli - Coleman [Ref. 2] and Boyce-DiPrima [Ref. 5]. The c, are determined once an initial
García-Peñarrubia, Pilar; Gálvez, Juan J; Gálvez, Jesús
2014-09-01
Cell signalling processes involve receptor trafficking through highly connected networks of interacting components. The binding of surface receptors to their specific ligands is a key factor for the control and triggering of signalling pathways. But the binding process still presents many enigmas and, by analogy with surface catalytic reactions, two different mechanisms can be conceived: the first mechanism is related to the Eley-Rideal (ER) mechanism, i.e. the bulk-dissolved ligand interacts directly by pure three-dimensional (3D) diffusion with the specific surface receptor; the second mechanism is similar to the Langmuir-Hinshelwood (LH) process, i.e. 3D diffusion of the ligand to the cell surface followed by reversible ligand adsorption and subsequent two-dimensional (2D) surface diffusion to the receptor. A situation where both mechanisms simultaneously contribute to the signalling process could also occur. The aim of this paper is to perform a computational study of the behavior of the signalling response when these different mechanisms for ligand-receptor interactions are integrated into a model for signal transduction and ligand transport. To this end, partial differential equations have been used to develop spatio-temporal models that show trafficking dynamics of ligands, cell surface components, and intracellular signalling molecules through the different domains of the system. The mathematical modeling developed for these mechanisms has been applied to the study of two situations frequently found in cell systems: (a) dependence of the signal response on cell density; and (b) enhancement of the signalling response in a synaptic environment.
Light detection and ranging measurements of wake dynamics. Part II: two-dimensional scanning
DEFF Research Database (Denmark)
Trujillo, Juan-José; Bingöl, Ferhat; Larsen, Gunner Chr.
2011-01-01
the instantaneous transversal wake position which is quantitatively compared with the prediction of the Dynamic Wake Meandering model. The results, shown for two 10-min time series, suggest that the conjecture of the wake behaving as a passive tracer is a fair approximation; this corroborates and expands...... the results of one-dimensional measurements already presented in the first part of this paper. Consequently, it is now possible to separate the deterministic and turbulent parts of the wake wind field, thus enabling capturing the wake in the meandering frame of reference. The results correspond, qualitatively...
Dynamic current-current susceptibility in three-dimensional Dirac and Weyl semimetals
Thakur, Anmol; Sadhukhan, Krishanu; Agarwal, Amit
2018-01-01
We study the linear response of doped three-dimensional Dirac and Weyl semimetals to vector potentials, by calculating the wave-vector- and frequency-dependent current-current response function analytically. The longitudinal part of the dynamic current-current response function is then used to study the plasmon dispersion and the optical conductivity. The transverse response in the static limit yields the orbital magnetic susceptibility. In a Weyl semimetal, along with the current-current response function, all these quantities are significantly impacted by the presence of parallel electric and magnetic fields (a finite E .B term) and can be used to experimentally explore the chiral anomaly.
System dynamics an introduction for mechanical engineers
Seeler, Karl A
2014-01-01
This essential textbook takes the student from the initial steps in modeling a dynamic system through development of the mathematical models needed for feedback control. The generously-illustrated, student-friendly text focuses on fundamental theoretical development rather than the application of commercial software. Practical details of machine design are included to motivate the non-mathematically inclined student. This book also: Emphasizes the linear graph method for modeling dynamic systems Offers a systematic approach for creating an engineering model, extracting information, and formulating mathematical analyses Adopts a unifying theme of power flow as the dynamic agent that eases analysis of hybrid systems, such as machinery Presents differential equations as dynamic operators and stresses input/output relationships Introduces Mathcad and programming in MATLAB Allows for use of Open Source Computational Software (R or C) Features over 1000 illustrations
Shape synchronization control for three-dimensional chaotic systems
International Nuclear Information System (INIS)
Huang, Yuanyuan; Wang, Yinhe; Chen, Haoguang; Zhang, Siying
2016-01-01
This paper aims to the three-dimensional continuous chaotic system and shape of the chaotic attractor by utilizing the basic theory of plane curves in classical differential geometry, the continuous controller is synthesized for the master–slave synchronization in shape. This means that the slave system can possess the same shape of state trajectory with the master system via the continuous controller. The continuous controller is composed of three sub-controllers, which respectively correspond to the master–slave synchronization in shape for the three projective curves of the chaotic attractor onto the three coordinate planes. Moreover, the proposed shape synchronization technique as well as application of control scheme to secure communication is also demonstrated in this paper, where numerical simulation results show the proposed control method works well.
Kulkov, V. M.; Medvedskii, A. L.; Terentyev, V. V.; Firsyuk, S. O.; Shemyakov, A. O.
2017-12-01
The problem of spacecraft attitude control using electromagnetic systems interacting with the Earth's magnetic field is considered. A set of dimensionless parameters has been formed to investigate the spacecraft orientation regimes based on dynamically similar models. The results of experimental studies of small spacecraft with a magnetic attitude control system can be extrapolated to the in-orbit spacecraft motion control regimes by using the methods of the dimensional and similarity theory.
System crash as dynamics of complex networks.
Yu, Yi; Xiao, Gaoxi; Zhou, Jie; Wang, Yubo; Wang, Zhen; Kurths, Jürgen; Schellnhuber, Hans Joachim
2016-10-18
Complex systems, from animal herds to human nations, sometimes crash drastically. Although the growth and evolution of systems have been extensively studied, our understanding of how systems crash is still limited. It remains rather puzzling why some systems, appearing to be doomed to fail, manage to survive for a long time whereas some other systems, which seem to be too big or too strong to fail, crash rapidly. In this contribution, we propose a network-based system dynamics model, where individual actions based on the local information accessible in their respective system structures may lead to the "peculiar" dynamics of system crash mentioned above. Extensive simulations are carried out on synthetic and real-life networks, which further reveal the interesting system evolution leading to the final crash. Applications and possible extensions of the proposed model are discussed.
Li, Xusong; Xie, Yu; Hu, Deping; Lan, Zhenggang
2017-10-10
On-the-fly trajectory-based nonadiabatic dynamics simulation has become an important approach to study ultrafast photochemical and photophysical processes in recent years. Because a large number of trajectories are generated from the dynamics simulation of polyatomic molecular systems with many degrees of freedom, the analysis of simulation results often suffers from the large amount of high-dimensional data. It is very challenging but meaningful to find dominating active coordinates from very complicated molecular motions. Dimensionality reduction techniques provide ideal tools to realize this purpose. We apply two dimensionality reduction approaches (classical multidimensional scaling and isometric feature mapping) to analyze the results of the on-the-fly surface-hopping nonadiabatic dynamics simulation. Two representative model systems, CH 2 NH 2 + and the phytochromobilin chromophore model, are chosen to examine the performance of these dimensionality reduction approaches. The results show that these approaches are very promising, because they can extract the major molecular motion from complicated time-dependent molecular evolution without preknown knowledge.
Controlling dynamics in diatomic systems
Indian Academy of Sciences (India)
WINTEC
2Center for Computational Natural Sciences and Bioinformatics,. International Institute of Information Technology, Hyderabad 500 032 ..... journal.34. 3. The control system. We have chosen two diatomic systems for studying the vibrational excitations from an initial state to a target state in a Morse potential of the HF and OH.
Kartsev, A; Karlsson, D; Privitera, A; Verdozzi, C
2013-01-01
Non-equilibrium quantum phenomena are ubiquitous in nature. Yet, theoretical predictions on the real-time dynamics of many-body quantum systems remain formidably challenging, especially for high dimensions, strong interactions or disordered samples. Here we consider a notable paradigm of strongly correlated Fermi systems, the Mott phase of the Hubbard model, in a setup resembling ultracold-gases experiments. We study the three-dimensional expansion of a cloud into an optical lattice after removing the confining potential. We use time-dependent density-functional theory combined with dynamical mean-field theory, considering interactions below and above the Mott threshold, as well as disorder effects. At strong coupling, we observe multiple timescales in the melting of the Mott wedding-cake structure, as the Mott plateau persist orders of magnitude longer than the band insulating core. We also show that disorder destabilises the Mott plateau and that, compared to a clean setup, localisation can decrease, creating an interesting dynamic crossover during the expansion.
Connection dynamics of higher-dimensional scalar-tensor theories of gravity
Han, Yu; Ma, Yongge; Zhang, Xiangdong
2014-09-01
The scalar-tensor theories (STTs) of gravity in spacetime dimensions (D+1)>2 are studied. By performing Hamiltonian analysis, we obtain the geometrical dynamics of the theories from their Lagrangian. The Hamiltonian formalism indicates that the theories are naturally divided into two sectors by the coupling parameter ω. The Hamiltonian structures in both sectors are similar to the corresponding structures of four-dimensional cases. It turns out that, similar to the case of general relativity (GR), there is also a symplectic reduction from the canonical structure of so(D+1) Yang-Mills theories coupled to the scalar field to the canonical structure of the geometrical STTs. Therefore, the non-perturbative loop quantum (LQG) gravity techniques can also be applied to the STTs in D+1 dimensions based on their connection-dynamical formalism.
Dynamical generation of fuzzy extra dimensions, dimensional reduction and symmetry breaking
Aschieri, Paolo; Grammatikopoulos, Theodoros; Steinacker, Harold; Zoupanos, George
2006-09-01
We present a renormalizable 4-dimensional SU(Script N) gauge theory with a suitable multiplet of scalar fields, which dynamically develops extra dimensions in the form of a fuzzy sphere S2N. We explicitly find the tower of massive Kaluza-Klein modes consistent with an interpretation as gauge theory on M4 × S2, the scalars being interpreted as gauge fields on S2. The gauge group is broken dynamically, and the low-energy content of the model is determined. Depending on the parameters of the model the low-energy gauge group can be SU(n), or broken further to SU(n1) × SU(n2) × U(1), with mass scale determined by the size of the extra dimension.
Magnetic field line random walk in two-dimensional dynamical turbulence
Wang, J. F.; Qin, G.; Ma, Q. M.; Song, T.; Yuan, S. B.
2017-08-01
The field line random walk (FLRW) of magnetic turbulence is one of the important topics in plasma physics and astrophysics. In this article, by using the field line tracing method, the mean square displacement (MSD) of FLRW is calculated on all possible length scales for pure two-dimensional turbulence with the damping dynamical model. We demonstrate that in order to describe FLRW with the damping dynamical model, a new dimensionless quantity R is needed to be introduced. On different length scales, dimensionless MSD shows different relationships with the dimensionless quantity R. Although the temporal effect affects the MSD of FLRW and even changes regimes of FLRW, it does not affect the relationship between the dimensionless MSD and dimensionless quantity R on all possible length scales.
Ten dimensional SO(10) G.U.T. models with dynamical symmetry breaking
International Nuclear Information System (INIS)
Hanlon, B.E.; Joshi, G.C.
1993-01-01
To date, considerations on SO (10) models within Coset Space Dimensional Reduction (CSDR) have been diagonalized to the standard model or rely upon imaginative applications of Wilson lines so as to avoid the problem of the nonexistence of an intermediate Higgs mechanism. However, there is an alternative approach involving four fermion condensates, breaking symmetries by a dynamical mechanism. Indeed, dynamical symmetry breaking has been the direction taken in some SU(5) models within this framework in order to avoid the problems of electroweak symmetry breaking at the compactification scale. This paper presents realistic models which utilize this mechanism. It is shown that the appropriate fermionic representations can emerge from CSDR and the construction of such condensates within the constraints of this scheme is presented. By introducing discrete symmetries onto the internal manifold a strong breaking of the SO(10) G.U.T. is produced and, more importantly, eliminate Higgs fields of geometrical origin. 31 refs
International Nuclear Information System (INIS)
Sidlichovsky, M.
1987-01-01
The conference proceedings contains a total of 31 papers of which 7 have not been incorporated in INIS. The papers mainly discuss the mathematical methods of calculating the movement of planets, their satellites and asteroids in the solar system and the mathematical modelling of the past development of the solar system. Great attention is also devoted to resonance in the solar system and to the study of many celestial bodies. Four papers are devoted to planetary rings and three to modern astrometry. (M.D.). 63 figs., 10 tabs., 520 refs
Hybrid dynamical systems observation and control
Defoort, Michael
2015-01-01
This book is a collection of contributions defining the state of current knowledge and new trends in hybrid systems – systems involving both continuous dynamics and discrete events – as described by the work of several well-known groups of researchers. Hybrid Dynamical Systems presents theoretical advances in such areas as diagnosability, observability and stabilization for various classes of system. Continuous and discrete state estimation and self-triggering control of nonlinear systems are advanced. The text employs various methods, among them, high-order sliding modes, Takagi–Sugeno representation and sampled-data switching to achieve its ends. The many applications of hybrid systems from power converters to computer science are not forgotten; studies of flexible-joint robotic arms and – as representative biological systems – the behaviour of the human heart and vasculature, demonstrate the wide-ranging practical significance of control in hybrid systems. The cross-disciplinary origins of study ...
Reductions in finite-dimensional integrable systems and special points of classical r-matrices
Skrypnyk, T.
2016-12-01
For a given 𝔤 ⊗ 𝔤-valued non-skew-symmetric non-dynamical classical r-matrices r(u, v) with spectral parameters, we construct the general form of 𝔤-valued Lax matrices of finite-dimensional integrable systems satisfying linear r-matrix algebra. We show that the reduction in the corresponding finite-dimensional integrable systems is connected with "the special points" of the classical r-matrices in which they become degenerated. We also propose a systematic way of the construction of additional integrals of the Lax-integrable systems associated with the symmetries of the corresponding r-matrices. We consider examples of the Lax matrices and integrable systems that are obtained in the framework of the general scheme. Among them there are such physically important systems as generalized Gaudin systems in an external magnetic field, ultimate integrable generalization of Toda-type chains (including "modified" or "deformed" Toda chains), generalized integrable Jaynes-Cummings-Dicke models, integrable boson models generalizing Bose-Hubbard dimer models, etc.