Relativistic stellar dynamics

International Nuclear Information System (INIS)

Contopoulos, G.

1983-01-01

In this paper, three main areas of relativistic stellar dynamics are reviewed: (a) The dynamics of clusters, or nuclei of galaxies, of very high density; (b) The dynamics of systems containing a massive black hole; and (c) The dynamics of particles (and photons) in an expanding Universe. The emphasis is on the use of orbit perturbations. (Auth.)

Sparse dynamical Boltzmann machine for reconstructing complex networks with binary dynamics

Science.gov (United States)

Chen, Yu-Zhong; Lai, Ying-Cheng

2018-03-01

Revealing the structure and dynamics of complex networked systems from observed data is a problem of current interest. Is it possible to develop a completely data-driven framework to decipher the network structure and different types of dynamical processes on complex networks? We develop a model named sparse dynamical Boltzmann machine (SDBM) as a structural estimator for complex networks that host binary dynamical processes. The SDBM attains its topology according to that of the original system and is capable of simulating the original binary dynamical process. We develop a fully automated method based on compressive sensing and a clustering algorithm to construct the SDBM. We demonstrate, for a variety of representative dynamical processes on model and real world complex networks, that the equivalent SDBM can recover the network structure of the original system and simulates its dynamical behavior with high precision.

Kinematics and dynamics analysis of a novel serial-parallel dynamic simulator

Energy Technology Data Exchange (ETDEWEB)

Hu, Bo; Zhang, Lian Dong; Yu, Jingjing [Parallel Robot and Mechatronic System Laboratory of Hebei Province, Yanshan University, Qinhuangdao, Hebei (China)

2016-11-15

A serial-parallel dynamics simulator based on serial-parallel manipulator is proposed. According to the dynamics simulator motion requirement, the proposed serial-parallel dynamics simulator formed by 3-RRS (active revolute joint-revolute joint-spherical joint) and 3-SPR (Spherical joint-active prismatic joint-revolute joint) PMs adopts the outer and inner layout. By integrating the kinematics, constraint and coupling information of the 3-RRS and 3-SPR PMs into the serial-parallel manipulator, the inverse Jacobian matrix, velocity, and acceleration of the serial-parallel dynamics simulator are studied. Based on the principle of virtual work and the kinematics model, the inverse dynamic model is established. Finally, the workspace of the (3-RRS)+(3-SPR) dynamics simulator is constructed.

Kinematics and dynamics analysis of a novel serial-parallel dynamic simulator

International Nuclear Information System (INIS)

Hu, Bo; Zhang, Lian Dong; Yu, Jingjing

2016-01-01

A serial-parallel dynamics simulator based on serial-parallel manipulator is proposed. According to the dynamics simulator motion requirement, the proposed serial-parallel dynamics simulator formed by 3-RRS (active revolute joint-revolute joint-spherical joint) and 3-SPR (Spherical joint-active prismatic joint-revolute joint) PMs adopts the outer and inner layout. By integrating the kinematics, constraint and coupling information of the 3-RRS and 3-SPR PMs into the serial-parallel manipulator, the inverse Jacobian matrix, velocity, and acceleration of the serial-parallel dynamics simulator are studied. Based on the principle of virtual work and the kinematics model, the inverse dynamic model is established. Finally, the workspace of the (3-RRS)+(3-SPR) dynamics simulator is constructed

Dynamic defense workshop :

Energy Technology Data Exchange (ETDEWEB)

Crosby, Sean Michael; Doak, Justin E.; Haas, Jason Juedes.; Helinski, Ryan; Lamb, Christopher C.

2013-02-01

On September 5th and 6th, 2012, the Dynamic Defense Workshop: From Research to Practice brought together researchers from academia, industry, and Sandia with the goals of increasing collaboration between Sandia National Laboratories and external organizations, de ning and un- derstanding dynamic, or moving target, defense concepts and directions, and gaining a greater understanding of the state of the art for dynamic defense. Through the workshop, we broadened and re ned our de nition and understanding, identi ed new approaches to inherent challenges, and de ned principles of dynamic defense. Half of the workshop was devoted to presentations of current state-of-the-art work. Presentation topics included areas such as the failure of current defenses, threats, techniques, goals of dynamic defense, theory, foundations of dynamic defense, future directions and open research questions related to dynamic defense. The remainder of the workshop was discussion, which was broken down into sessions on de ning challenges, applications to host or mobile environments, applications to enterprise network environments, exploring research and operational taxonomies, and determining how to apply scienti c rigor to and investigating the eld of dynamic defense.

Dynamic characteristics of lead rubber bearings with dynamic two-dimensional test equipment

International Nuclear Information System (INIS)

Ohtori, Y.; Ishida, K.; Mazda, T.

1994-01-01

Although studies have previously been done on the static mechanical properties of lead rubber bearings, this study aims to grasp the dynamic characteristics of lead rubber bearings from experimental results, using two-dimensional dynamic test equipment which is designed to grasp in detail such dynamic characteristics as deformation capacity and proof stress. This paper describes the results from three types of tests: (1) dynamic mechanical properties tests, (2) cyclic loading tests, and (3) dynamic ultimate tests. Through these tests, it was confirmed that the dynamic characteristics of lead rubber bearings are independent of strain rate

Peri-dynamics

International Nuclear Information System (INIS)

Littlewood, D.

2015-01-01

Peri-dynamics, a nonlocal extension of continuum mechanics, is a natural framework for capturing constitutive response and modelling pervasive material failure and fracture. Unlike classical approaches incorporating partial derivatives, the peri-dynamic governing equations utilise integral expressions that remain valid in the presence of discontinuities such as cracks. The mathematical theory of peri-dynamics unifies the mechanics of continuous media, cracks, and discrete particles. The result is a consistent framework for capturing a wide range of constitutive responses, including inelasticity, in combination with robust material failure laws. Peri-dynamics has been implemented in a number of computational simulation codes, including the open source code Peridigm and the Sierra/SolidMechanics analysis code at Sandia National Laboratories. (author)

Emerging of Stochastic Dynamical Equalities and Steady State Thermodynamics from Darwinian Dynamics

International Nuclear Information System (INIS)

Ao, P.

2008-01-01

The evolutionary dynamics first conceived by Darwin and Wallace, referring to as Darwinian dynamics in the present paper, has been found to be universally valid in biology. The statistical mechanics and thermodynamics, while enormous successful in physics, have been in an awkward situation of wanting a consistent dynamical understanding. Here we present from a formal point of view an exploration of the connection between thermodynamics and Darwinian dynamics and a few related topics. We first show that the stochasticity in Darwinian dynamics implies the existence temperature, hence the canonical distribution of Boltzmann-Gibbs type. In term of relative entropy the Second Law of thermodynamics is dynamically demonstrated without detailed balance condition, and is valid regardless of size of the system. In particular, the dynamical component responsible for breaking detailed balance condition does not contribute to the change of the relative entropy. Two types of stochastic dynamical equalities of current interest are explicitly discussed in the present approach: One is based on Feynman-Kac formula and another is a generalization of Einstein relation. Both are directly accessible to experimental tests. Our demonstration indicates that Darwinian dynamics represents logically a simple and straightforward starting point for statistical mechanics and thermodynamics and is complementary to and consistent with conservative dynamics that dominates the physical sciences. Present exploration suggests the existence of a unified stochastic dynamical framework both near and far from equilibrium

Cluster dynamics transcending chemical dynamics toward nuclear fusion.

Science.gov (United States)

Heidenreich, Andreas; Jortner, Joshua; Last, Isidore

2006-07-11

Ultrafast cluster dynamics encompasses femtosecond nuclear dynamics, attosecond electron dynamics, and electron-nuclear dynamics in ultraintense laser fields (peak intensities 10(15)-10(20) W.cm(-2)). Extreme cluster multielectron ionization produces highly charged cluster ions, e.g., (C(4+)(D(+))(4))(n) and (D(+)I(22+))(n) at I(M) = 10(18) W.cm(-2), that undergo Coulomb explosion (CE) with the production of high-energy (5 keV to 1 MeV) ions, which can trigger nuclear reactions in an assembly of exploding clusters. The laser intensity and the cluster size dependence of the dynamics and energetics of CE of (D(2))(n), (HT)(n), (CD(4))(n), (DI)(n), (CD(3)I)(n), and (CH(3)I)(n) clusters were explored by electrostatic models and molecular dynamics simulations, quantifying energetic driving effects, and kinematic run-over effects. The optimization of table-top dd nuclear fusion driven by CE of deuterium containing heteroclusters is realized for light-heavy heteroclusters of the largest size, which allows for the prevalence of cluster vertical ionization at the highest intensity of the laser field. We demonstrate a 7-orders-of-magnitude enhancement of the yield of dd nuclear fusion driven by CE of light-heavy heteroclusters as compared with (D(2))(n) clusters of the same size. Prospective applications for the attainment of table-top nucleosynthesis reactions, e.g., (12)C(P,gamma)(13)N driven by CE of (CH(3)I)(n) clusters, were explored.

Development Of Dynamic Probabilistic Safety Assessment: The Accident Dynamic Simulator (ADS) Tool

International Nuclear Information System (INIS)

Chang, Y.H.; Mosleh, A.; Dang, V.N.

2003-01-01

The development of a dynamic methodology for Probabilistic Safety Assessment (PSA) addresses the complex interactions between the behaviour of technical systems and personnel response in the evolution of accident scenarios. This paper introduces the discrete dynamic event tree, a framework for dynamic PSA, and its implementation in the Accident Dynamic Simulator (ADS) tool. Dynamic event tree tools generate and quantify accident scenarios through coupled simulation models of the plant physical processes, its automatic systems, the equipment reliability, and the human response. The current research on the framework, the ADS tool, and on Human Reliability Analysis issues within dynamic PSA, is discussed. (author)

Development Of Dynamic Probabilistic Safety Assessment: The Accident Dynamic Simulator (ADS) Tool

Energy Technology Data Exchange (ETDEWEB)

Chang, Y.H.; Mosleh, A.; Dang, V.N

2003-03-01

The development of a dynamic methodology for Probabilistic Safety Assessment (PSA) addresses the complex interactions between the behaviour of technical systems and personnel response in the evolution of accident scenarios. This paper introduces the discrete dynamic event tree, a framework for dynamic PSA, and its implementation in the Accident Dynamic Simulator (ADS) tool. Dynamic event tree tools generate and quantify accident scenarios through coupled simulation models of the plant physical processes, its automatic systems, the equipment reliability, and the human response. The current research on the framework, the ADS tool, and on Human Reliability Analysis issues within dynamic PSA, is discussed. (author)

Dynamic Boiler Performance

DEFF Research Database (Denmark)

Sørensen, Kim

Traditionally, boilers have been designed mainly focussing on the static operation of the plant. The dynamic capability has been given lower priority and the analysis has typically been limited to assuring that the plant was not over-stressed due to large temperature gradients. New possibilities...... developed. Analyzing boilers for dynamic operation gives rise to a number of opposing aims: shrinking and swelling, steam quality, stress levels, control system/philosophy, pressurization etc. Common for these opposing aims is that an optimum can be found for selected operation conditions. The framework has...... for buying and selling energy has increased the focus on the dynamic operation capability, efciency, emissions etc. For optimizing the design of boilers for dynamic operation a quantication of the dynamic capability is needed. A framework for optimizing design of boilers for dynamic operation has been...

Testing of dynamic multileaf collimator by dynamic log file

International Nuclear Information System (INIS)

Ono, Kaoru; Nakamura, Tetsuji; Yamato, Shinichirou; Miyazawa, Masanori

2007-01-01

Intensity-modulated radiation therapy (IMRT) represents one of the most significant technical advances in radiation therapy. In the dynamic multileaf collimator (MLC) method of IMRT delivery, because of the relatively small gaps between opposed leaves and because most regions are shielded by leaves most of the time, the delivered dose is very sensitive to MLC leaf positional accuracy. A variation of ±0.2 mm in the gap width can result in a dose variation of ±3% for each clinical dynamic MLC field. Most often the effects of leaf motion are inferred from dose deviations on film or from variations in ionization measurements. These techniques provide dosimetric information but do not provide detailed information for diagnosing delivery problems. Therefore, a dynamic log file (Dynalog file) was used to verify dynamic MLC leaf positional accuracy. Measuring for narrow gaps using the thickness gauge could detect a log file accuracy of approximately 0.1 mm. The accuracy of dynamic MLC delivery depends on the accuracy with which the velocity of each leaf is controlled. We studied the relationship between leaf positional accuracy and leaf velocity. Leaf velocity of 0.7 cm/sec caused approximately 0.2 mm leaf positional variation. We then analyzed leaf positional accuracy for the clinical dynamic MLC field using Dynalog File Viewer (Varian Medical Systems, Inc., Palo Alto, California (CA)), and developed a new program that can analyze more detailed leaf motions. Using this program, we can obtain more detailed information, and therefore can determine the source of dose uncertainties for the dynamic MLC field. (author)

Dynamic neutron scattering from conformational dynamics. I. Theory and Markov models.

Science.gov (United States)

Lindner, Benjamin; Yi, Zheng; Prinz, Jan-Hendrik; Smith, Jeremy C; Noé, Frank

2013-11-07

The dynamics of complex molecules can be directly probed by inelastic neutron scattering experiments. However, many of the underlying dynamical processes may exist on similar timescales, which makes it difficult to assign processes seen experimentally to specific structural rearrangements. Here, we show how Markov models can be used to connect structural changes observed in molecular dynamics simulation directly to the relaxation processes probed by scattering experiments. For this, a conformational dynamics theory of dynamical neutron and X-ray scattering is developed, following our previous approach for computing dynamical fingerprints of time-correlation functions [F. Noé, S. Doose, I. Daidone, M. Löllmann, J. Chodera, M. Sauer, and J. Smith, Proc. Natl. Acad. Sci. U.S.A. 108, 4822 (2011)]. Markov modeling is used to approximate the relaxation processes and timescales of the molecule via the eigenvectors and eigenvalues of a transition matrix between conformational substates. This procedure allows the establishment of a complete set of exponential decay functions and a full decomposition into the individual contributions, i.e., the contribution of every atom and dynamical process to each experimental relaxation process.

Complexity and Dynamical Depth

Directory of Open Access Journals (Sweden)

Terrence Deacon

2014-07-01

Full Text Available We argue that a critical difference distinguishing machines from organisms and computers from brains is not complexity in a structural sense, but a difference in dynamical organization that is not well accounted for by current complexity measures. We propose a measure of the complexity of a system that is largely orthogonal to computational, information theoretic, or thermodynamic conceptions of structural complexity. What we call a system’s dynamical depth is a separate dimension of system complexity that measures the degree to which it exhibits discrete levels of nonlinear dynamical organization in which successive levels are distinguished by local entropy reduction and constraint generation. A system with greater dynamical depth than another consists of a greater number of such nested dynamical levels. Thus, a mechanical or linear thermodynamic system has less dynamical depth than an inorganic self-organized system, which has less dynamical depth than a living system. Including an assessment of dynamical depth can provide a more precise and systematic account of the fundamental difference between inorganic systems (low dynamical depth and living systems (high dynamical depth, irrespective of the number of their parts and the causal relations between them.

The Theory of Dynamic Public Transit Priority with Dynamic Stochastic Park and Ride

Directory of Open Access Journals (Sweden)

Chengming Zhu

2014-01-01

Full Text Available Public transit priority is very important for relieving traffic congestion. The connotation of dynamic public transit priority and dynamic stochastic park and ride is presented. Based on the point that the travel cost of public transit is not higher than the travel cost of car, how to determine the level of dynamic public transit priority is discussed. The traffic organization method of dynamic public transit priority is introduced. For dynamic stochastic park and ride, layout principle, scale, and charging standard are discussed. Traveler acceptability is high through the analysis of questionnaire survey. Dynamic public transit priority with dynamic stochastic park and ride has application feasibility.

The Influence of Dynamic Contact Angle on Wetting Dynamics

Science.gov (United States)

Rame, Enrique; Garoff, Steven

2005-01-01

When surface tension forces dominate, and regardless of whether the situation is static or dynamic, the contact angle (the angle the interface between two immiscible fluids makes when it contacts a solid) is the key parameter that determines the shape of a fluid-fluid interface. The static contact angle is easy to measure and implement in models predicting static capillary surface shapes and such associated quantities as pressure drops. By contrast, when the interface moves relative to the solid (as in dynamic wetting processes) the dynamic contact angle is not identified unambiguously because it depends on the geometry of the system Consequently, its determination becomes problematic and measurements in one geometry cannot be applied in another for prediction purposes. However, knowing how to measure and use the dynamic contact angle is crucial to determine such dynamics as a microsystem throughput reliably. In this talk we will present experimental and analytical efforts aimed at resolving modeling issues present in dynamic wetting. We will review experiments that show the inadequacy of the usual hydrodynamic model when a fluid-fluid meniscus moves over a solid surface such as the wall of a small tube or duct. We will then present analytical results that show how to parametrize these problems in a predictive manner. We will illustrate these ideas by showing how to implement the method in numerical fluid mechanical calculations.

Jumping Dynamics

DEFF Research Database (Denmark)

Sannino, Francesco

2013-01-01

paradigm the physical scale and henceforth also the massive spectrum of the theory jump at the lower boundary of the conformal window. In particular we propose that a theory can suddenly jump from a Quantum Chromodynamics type spectrum, at the lower boundary of the conformal window, to a conformal one...... without particle interpretation. The jumping scenario, therefore, does not support a near-conformal dynamics of walking type. We will also discuss the impact of jumping dynamics on the construction of models of dynamical electroweak symmetry breaking....

Galactic dynamics

CERN Document Server

Binney, James

2008-01-01

Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many section

Engineering quantum dynamics

International Nuclear Information System (INIS)

Lloyd, Seth; Viola, Lorenza

2002-01-01

The ability to perform measurements on a quantum system, combined with the ability to feed back the measurement results via coherent control, allows one to control the system to follow any desired coherent or incoherent quantum dynamics. Such universal dynamical control can be achieved, in principle, through the repeated application of only two coherent control operations and a simple 'Yes-No' measurement. As a consequence, a quantum computer can simulate an arbitrary open-system dynamics using just one qubit more than required to simulate closed-system dynamics

Dynamical principles in neuroscience

International Nuclear Information System (INIS)

Rabinovich, Mikhail I.; Varona, Pablo; Selverston, Allen I.; Abarbanel, Henry D. I.

2006-01-01

Dynamical modeling of neural systems and brain functions has a history of success over the last half century. This includes, for example, the explanation and prediction of some features of neural rhythmic behaviors. Many interesting dynamical models of learning and memory based on physiological experiments have been suggested over the last two decades. Dynamical models even of consciousness now exist. Usually these models and results are based on traditional approaches and paradigms of nonlinear dynamics including dynamical chaos. Neural systems are, however, an unusual subject for nonlinear dynamics for several reasons: (i) Even the simplest neural network, with only a few neurons and synaptic connections, has an enormous number of variables and control parameters. These make neural systems adaptive and flexible, and are critical to their biological function. (ii) In contrast to traditional physical systems described by well-known basic principles, first principles governing the dynamics of neural systems are unknown. (iii) Many different neural systems exhibit similar dynamics despite having different architectures and different levels of complexity. (iv) The network architecture and connection strengths are usually not known in detail and therefore the dynamical analysis must, in some sense, be probabilistic. (v) Since nervous systems are able to organize behavior based on sensory inputs, the dynamical modeling of these systems has to explain the transformation of temporal information into combinatorial or combinatorial-temporal codes, and vice versa, for memory and recognition. In this review these problems are discussed in the context of addressing the stimulating questions: What can neuroscience learn from nonlinear dynamics, and what can nonlinear dynamics learn from neuroscience?

Dynamical principles in neuroscience

Science.gov (United States)

Rabinovich, Mikhail I.; Varona, Pablo; Selverston, Allen I.; Abarbanel, Henry D. I.

2006-10-01

Dynamical modeling of neural systems and brain functions has a history of success over the last half century. This includes, for example, the explanation and prediction of some features of neural rhythmic behaviors. Many interesting dynamical models of learning and memory based on physiological experiments have been suggested over the last two decades. Dynamical models even of consciousness now exist. Usually these models and results are based on traditional approaches and paradigms of nonlinear dynamics including dynamical chaos. Neural systems are, however, an unusual subject for nonlinear dynamics for several reasons: (i) Even the simplest neural network, with only a few neurons and synaptic connections, has an enormous number of variables and control parameters. These make neural systems adaptive and flexible, and are critical to their biological function. (ii) In contrast to traditional physical systems described by well-known basic principles, first principles governing the dynamics of neural systems are unknown. (iii) Many different neural systems exhibit similar dynamics despite having different architectures and different levels of complexity. (iv) The network architecture and connection strengths are usually not known in detail and therefore the dynamical analysis must, in some sense, be probabilistic. (v) Since nervous systems are able to organize behavior based on sensory inputs, the dynamical modeling of these systems has to explain the transformation of temporal information into combinatorial or combinatorial-temporal codes, and vice versa, for memory and recognition. In this review these problems are discussed in the context of addressing the stimulating questions: What can neuroscience learn from nonlinear dynamics, and what can nonlinear dynamics learn from neuroscience?

Comparison of cardiovascular response to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone in patients with chronic ischemic heart disease

International Nuclear Information System (INIS)

Hung, J.; McKillip, J.; Savin, W.; Magder, S.; Kraus, R.; Houston, N.; Goris, M.; Haskell, W.; DeBusk, R.

1982-01-01

The cardiovascular responses to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone were evaluated by upright bicycle ergometry during equilibrium-gated blood pool scintigraphy in 24 men, mean age 59 +/- 8 years, with chronic ischemic heart disease. Combined static-dynamic effort and the postprandial state elicited a peak cardiovascular response similar to that of dynamic effort alone. Heart rate, intraarterial systolic and diastolic pressures, rate-pressure product and ejection fraction were similar for the three test conditions at the onset of ischemia and at peak effort. The prevalence and extent of exercise-induced ischemic left ventricular dysfunction, ST-segment depression, angina pectoris and ventricular ectopic activity were also similar during the three test conditions. Direct and indirect measurements of systolic and diastolic blood pressure were highly correlated. The onset of ischemic ST-segment depression and angina pectoris correlated as strongly with heart rate alone as with the rate-pressure product during all three test conditions. The cardiovascular response to combined static-dynamic effort and to postprandial dynamic effort becomes more similar to that of dynamic effort alone as dynamic effort reaches a symptom limit. If significant ischemic and arrhythmic abnormalities are absent during symptom-limited dynamic exercise testing, they are unlikely to appear during combined static-dynamic or postprandial dynamic effort

Dynamic neutron scattering from conformational dynamics. II. Application using molecular dynamics simulation and Markov modeling.

Science.gov (United States)

Yi, Zheng; Lindner, Benjamin; Prinz, Jan-Hendrik; Noé, Frank; Smith, Jeremy C

2013-11-07

Neutron scattering experiments directly probe the dynamics of complex molecules on the sub pico- to microsecond time scales. However, the assignment of the relaxations seen experimentally to specific structural rearrangements is difficult, since many of the underlying dynamical processes may exist on similar timescales. In an accompanying article, we present a theoretical approach to the analysis of molecular dynamics simulations with a Markov State Model (MSM) that permits the direct identification of structural transitions leading to each contributing relaxation process. Here, we demonstrate the use of the method by applying it to the configurational dynamics of the well-characterized alanine dipeptide. A practical procedure for deriving the MSM from an MD is introduced. The result is a 9-state MSM in the space of the backbone dihedral angles and the side-chain methyl group. The agreement between the quasielastic spectrum calculated directly from the atomic trajectories and that derived from the Markov state model is excellent. The dependence on the wavevector of the individual Markov processes is described. The procedure means that it is now practicable to interpret quasielastic scattering spectra in terms of well-defined intramolecular transitions with minimal a priori assumptions as to the nature of the dynamics taking place.

Principles of magnetoplasma dynamics

International Nuclear Information System (INIS)

Woods, L.C.

1987-01-01

A self-contained account is given of magnetoplasma dynamics covering fluid dynamics, thermodynamics, kinetic theory of gases, particle dynamics and electromagnetism. The six chapter headings are, basic concepts, magnetohydrodynamics, dynamics of charged particles, transport in a magnetoplasma, magnetoplasma shock waves, and transport in tokamaks. There are 231 references. (U.K.)

Forest dynamics.

Science.gov (United States)

Frelich, Lee

2016-01-01

Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

A Dynamic Continuation-Passing Style for Dynamic Delimited Continuations

DEFF Research Database (Denmark)

Biernacki, Dariusz; Danvy, Olivier; Millikin, Kevin Scott

2005-01-01

We present a new abstract machine that accounts for dynamic delimited continuations. We prove the correctness of this new abstract machine with respect to a pre-existing, definitional abstract machine. Unlike this definitional abstract machine, the new abstract machine is in defunctionalized form......, which makes it possible to state the corresponding higher-order evaluator. This evaluator is in continuation+state passing style and threads a trail of delimited continuations and a meta-continuation. Since this style accounts for dynamic delimited continuations, we refer to it as `dynamic continuation......-passing style.' We show that the new machine operates more efficiently than the definitional one and that the notion of computation induced by the corresponding evaluator takes the form of a monad. We also present new examples and a new simulation of dynamic delimited continuations in terms of static ones....

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

Fundamentals of structural dynamics

CERN Document Server

Craig, Roy R

2006-01-01

From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e

Modern fluid dynamics

CERN Document Server

Kleinstreuer, Clement

2018-01-01

Modern Fluid Dynamics, Second Edition provides up-to-date coverage of intermediate and advanced fluids topics. The text emphasizes fundamentals and applications, supported by worked examples and case studies. Scale analysis, non-Newtonian fluid flow, surface coating, convection heat transfer, lubrication, fluid-particle dynamics, microfluidics, entropy generation, and fluid-structure interactions are among the topics covered. Part A presents fluids principles, and prepares readers for the applications of fluid dynamics covered in Part B, which includes computer simulations and project writing. A review of the engineering math needed for fluid dynamics is included in an appendix.

The Theory of Dynamic Public Transit Priority with Dynamic Stochastic Park and Ride

OpenAIRE

Zhu, Chengming; Chen, Yanyan; Ma, Changxi

2014-01-01

Public transit priority is very important for relieving traffic congestion. The connotation of dynamic public transit priority and dynamic stochastic park and ride is presented. Based on the point that the travel cost of public transit is not higher than the travel cost of car, how to determine the level of dynamic public transit priority is discussed. The traffic organization method of dynamic public transit priority is introduced. For dynamic stochastic park and ride, layout principle, scal...

Double dynamic scaling in human communication dynamics

Science.gov (United States)

Wang, Shengfeng; Feng, Xin; Wu, Ye; Xiao, Jinhua

2017-05-01

In the last decades, human behavior has been deeply understanding owing to the huge quantities data of human behavior available for study. The main finding in human dynamics shows that temporal processes consist of high-activity bursty intervals alternating with long low-activity periods. A model, assuming the initiator of bursty follow a Poisson process, is widely used in the modeling of human behavior. Here, we provide further evidence for the hypothesis that different bursty intervals are independent. Furthermore, we introduce a special threshold to quantitatively distinguish the time scales of complex dynamics based on the hypothesis. Our results suggest that human communication behavior is a composite process of double dynamics with midrange memory length. The method for calculating memory length would enhance the performance of many sequence-dependent systems, such as server operation and topic identification.

Dynamic Capabilities

DEFF Research Database (Denmark)

Grünbaum, Niels Nolsøe; Stenger, Marianne

2013-01-01

The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case enterprises, as we would expect. It was, however, not possible to establish a positive relationship between innovation performance and profitability. Nor was there any positive...... relationship between dynamic capabilities and profitability....

Dynamic covalent gels assembled from small molecules:from discrete gelators to dynamic covalent polymers

Institute of Scientific and Technical Information of China (English)

Jian-Yong Zhang; Li-Hua Zeng; Juan Feng

2017-01-01

Dynamic covalent chemistry has emerged recently to be a powerful tool to construct functional materials.This article reviews the progress in the research and development of dynamic covalent chemistry in gels assembled from small molecules.First dynamic covalent reactions used in gels are reviewed to understand the dynamic covalent bonding.Afterwards the catalogues of dynamic covalent gels are reviewed according to the nature of gelators and the interactions between gelators.Dynamic covalent bonding can be involved to form low molecular weight gelators.Low molecular weight molecules with multiple functional groups react to form dynamic covalent cross-linked polymers and act as gelators.Two catalogues of gels show different properties arising from their different structures.This review aims to illustrate the structure-property relationships of these dynamic covalent gels.

Vehicle dynamics theory and application

CERN Document Server

Jazar, Reza N

2017-01-01

This intermediate textbook is appropriate for students in vehicle dynamics courses, in their last year of undergraduate study or their first year of graduate study. It is also appropriate for mechanical engineers, automotive engineers, and researchers in the area of vehicle dynamics for continuing education or as a reference. It addresses fundamental and advanced topics, and a basic knowledge of kinematics and dynamics, as well as numerical methods, is expected. The contents are kept at a theoretical-practical level, with a strong emphasis on application. This third edition has been reduced by 25%, to allow for coverage over one semester, as opposed to the previous edition that needed two semesters for coverage. The textbook is composed of four parts: Vehicle Motion: covers tire dynamics, forward vehicle dynamics, and driveline dynamics Vehicle Kinematics: covers applied kinematics, applied mechanisms, steering dynamics, and suspension mechanisms Vehicle Dynamics: covers applied dynamics, vehicle planar dynam...

Structural dynamics

CERN Document Server

Strømmen, Einar N

2014-01-01

This book introduces to the theory of structural dynamics, with focus on civil engineering structures that may be described by line-like beam or beam-column type of systems, or by a system of rectangular plates. Throughout this book the mathematical presentation contains a classical analytical description as well as a description in a discrete finite element format, covering the mathematical development from basic assumptions to the final equations ready for practical dynamic response predictions. Solutions are presented in time domain as well as in frequency domain. Structural Dynamics starts off at a basic level and step by step brings the reader up to a level where the necessary safety considerations to wind or horizontal ground motion induced dynamic design problems can be performed. The special theory of the tuned mass damper has been given a comprehensive treatment, as this is a theory not fully covered elsewhere. For the same reason a chapter on the problem of moving loads on beams has been included.

Dynamic map labeling.

Science.gov (United States)

Been, Ken; Daiches, Eli; Yap, Chee

2006-01-01

We address the problem of filtering, selecting and placing labels on a dynamic map, which is characterized by continuous zooming and panning capabilities. This consists of two interrelated issues. The first is to avoid label popping and other artifacts that cause confusion and interrupt navigation, and the second is to label at interactive speed. In most formulations the static map labeling problem is NP-hard, and a fast approximation might have O(nlogn) complexity. Even this is too slow during interaction, when the number of labels shown can be several orders of magnitude less than the number in the map. In this paper we introduce a set of desiderata for "consistent" dynamic map labeling, which has qualities desirable for navigation. We develop a new framework for dynamic labeling that achieves the desiderata and allows for fast interactive display by moving all of the selection and placement decisions into the preprocessing phase. This framework is general enough to accommodate a variety of selection and placement algorithms. It does not appear possible to achieve our desiderata using previous frameworks. Prior to this paper, there were no formal models of dynamic maps or of dynamic labels; our paper introduces both. We formulate a general optimization problem for dynamic map labeling and give a solution to a simple version of the problem. The simple version is based on label priorities and a versatile and intuitive class of dynamic label placements we call "invariant point placements". Despite these restrictions, our approach gives a useful and practical solution. Our implementation is incorporated into the G-Vis system which is a full-detail dynamic map of the continental USA. This demo is available through any browser.

Bursty human dynamics

CERN Document Server

Karsai, Márton; Kaski, Kimmo

2018-01-01

This book provides a comprehensive overview on emergent bursty patterns in the dynamics of human behaviour. It presents common and alternative understanding of the investigated phenomena, and points out open questions worthy of further investigations. The book is structured as follows. In the introduction the authors discuss the motivation of the field, describe bursty phenomena in case of human behaviour, and relate it to other disciplines. The second chapter addresses the measures commonly used to characterise heterogeneous signals, bursty human dynamics, temporal paths, and correlated behaviour. These definitions are first introduced to set the basis for the discussion of the third chapter about the observations of bursty human patterns in the dynamics of individuals, dyadic interactions, and collective behaviour. The subsequent fourth chapter discusses the models of bursty human dynamics. Various mechanisms have been proposed about the source of the heterogeneities in human dynamics, which leads to the in...

Water Dynamics in Protein Hydration Shells: The Molecular Origins of the Dynamical Perturbation

Science.gov (United States)

2014-01-01

Protein hydration shell dynamics play an important role in biochemical processes including protein folding, enzyme function, and molecular recognition. We present here a comparison of the reorientation dynamics of individual water molecules within the hydration shell of a series of globular proteins: acetylcholinesterase, subtilisin Carlsberg, lysozyme, and ubiquitin. Molecular dynamics simulations and analytical models are used to access site-resolved information on hydration shell dynamics and to elucidate the molecular origins of the dynamical perturbation of hydration shell water relative to bulk water. We show that all four proteins have very similar hydration shell dynamics, despite their wide range of sizes and functions, and differing secondary structures. We demonstrate that this arises from the similar local surface topology and surface chemical composition of the four proteins, and that such local factors alone are sufficient to rationalize the hydration shell dynamics. We propose that these conclusions can be generalized to a wide range of globular proteins. We also show that protein conformational fluctuations induce a dynamical heterogeneity within the hydration layer. We finally address the effect of confinement on hydration shell dynamics via a site-resolved analysis and connect our results to experiments via the calculation of two-dimensional infrared spectra. PMID:24479585

Dynamic magnetizations and dynamic phase transitions in a transverse cylindrical Ising nanowire

International Nuclear Information System (INIS)

Deviren, Bayram; Ertaş, Mehmet; Keskin, Mustafa

2012-01-01

In this paper, we extend the paper of Kaneyoshi (2010 J. Magn. Magn. Mater. 322 3410-5) to investigate the dynamic magnetizations and dynamic phase transitions of a transverse cylindrical Ising nanowire system by using the effective field theory with correlations and the Glauber-type stochastic dynamics under a time-dependent oscillating external magnetic field. The dynamic effective field equations for the average longitudinal and transverse magnetizations on the surface shell and core are derived by using the Glauber transition rates. Temperature dependences of the dynamic longitudinal magnetizations, the transverse magnetizations and the total magnetizations are investigated in order to characterize the nature (first- or second-order) of the dynamic transitions as well as the dynamic phase transition temperatures and the compensation behaviors. The system is strongly affected by the surface situations. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and the core. According to the values of Hamiltonian parameters, four different types of compensation behaviors in the Néel classification nomenclature exist in the system. The results are compared with some theoretical works and good overall agreement is observed. (paper)

Temperature dependent dynamics of DegP-trimer: A molecular dynamics study

Directory of Open Access Journals (Sweden)

Nivedita Rai

2015-01-01

Full Text Available DegP is a heat shock protein from high temperature requirement protease A family, which reacts to the environmental stress conditions in an ATP independent way. The objective of the present analysis emerged from the temperature dependent functional diversity of DegP between chaperonic and protease activities at temperatures below and above 28 °C, respectively. DegP is a multimeric protein and the minimal functional unit, DegP-trimer, is of great importance in understanding the DegP pathway. The structural aspects of DegP-trimer with respect to temperature variation have been studied using molecular dynamics simulations (for 100 ns and principal component analysis to highlight the temperature dependent dynamics facilitating its functional diversity. The DegP-trimer revealed a pronounced dynamics at both 280 and 320 K, when compared to the dynamics observed at 300 K. The LA loop is identified as the highly flexible region during dynamics and at extreme temperatures, the residues 46–80 of LA loop express a flip towards right (at 280 and left ( at 320 K with respect to the fixed β-sheet connecting the LA loop of protease for which Phe46 acts as one of the key residues. Such dynamics of LA loop facilitates inter-monomeric interaction with the PDZ1 domain of the neighbouring monomer and explains its active participation when DegP exists as trimer. Hence, the LA loop mediated dynamics of DegP-trimer is expected to provide further insight into the temperature dependent dynamics of DegP towards the understanding of its assembly and functional diversity in the presence of substrate.

System dynamics with interaction discontinuity

CERN Document Server

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.

Offshore pipelaying dynamics

Energy Technology Data Exchange (ETDEWEB)

Jensen, Gullik Anthon

2010-02-15

This thesis considers three issues regarding modeling of of offshore pipe laying dynamics. These are: (i) the formulation of an offshore pipeline installation operation as a control problem, (ii) the development and passivity analysis of a robotic pipe model for a submerged pipe string, suitable for real-time applications in closed- loop control systems, and (iii) the development and validation of a nonlinear FEM model for simulation and control of the elastic pipeline dynamics, including FEM dynamics of a pipeline combined with vessel dynamics, for simulation and control of pipe lay operations under dynamic positioning Pipeline installation is defined as the operation of positioning a pipeline along a reference path on the seabed from a surface vessel. In control terms, this can be stated as a path-following control problem, where the pipe touchdown point tracks the reference path. However, the only controllers for the touchdown point are the pay-out of pipe into the water, and the motion of the surface vessel. Considering that the pipe is an elastic body, and that both the pipe and the vessel are subject to environmental loads, the control problem that must be considered is a dynamic target-tracking problem, where the surface vessel must track a moving target position on the surface in order to control the position of the touchdown point. A target-tracking controller may be implemented as a guidance system, by extending the dynamic positioning system that is common for pipe lay vessels. An important component in the guidance system is the dynamic pipe model mapping touchdown and surface vessel position. Motivated by robotics, a compact system formulation is derived for the suspended pipeline by considering it as a hyper-redundant manipulator with an arbitrary number of links. This model captures the main dynamics of the pipe, including its geometric configuration and top tension. The model is in the state- space, and on a vectorial form using minimal coordinates

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.

Dynamic Systems and Control Engineering

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Seok

1994-02-15

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.

Dynamical Systems Conference

CERN Document Server

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.

Micro-Level Affect Dynamics in Psychopathology Viewed From Complex Dynamical System Theory

NARCIS (Netherlands)

Wichers, M.; Wigman, J. T. W.; Myin-Germeys, I.

2015-01-01

This article discusses the role of moment-to-moment affect dynamics in mental disorder and aims to integrate recent literature on this topic in the context of complex dynamical system theory. First, we will review the relevance of temporal and contextual aspects of affect dynamics in relation to

Nonlinear dynamics non-integrable systems and chaotic dynamics

CERN Document Server

Borisov, Alexander

2017-01-01

This monograph reviews advanced topics in the area of nonlinear dynamics. Starting with theory of integrable systems – including methods to find and verify integrability – the remainder of the book is devoted to non-integrable systems with an emphasis on dynamical chaos. Topics include structural stability, mechanisms of emergence of irreversible behaviour in deterministic systems as well as chaotisation occurring in dissipative systems.

Perspectives of nonlinear dynamics

International Nuclear Information System (INIS)

Jackson, E.A.

1985-03-01

Four lectures were given weekly in October and November, 1984, and some of the ideas presented here will be of use in the future. First, a brief survey of the historical development of nonlinear dynamics since about 1890 was given, and then, a few topics were discussed in detail. The objective was to introduce some of many concepts and methods which are presently used for describing nonlinear dynamics. The symbiotic relationship between sciences of all types and mathematics, two main categories of the models describing nature, the method for describing the dynamics of a system, the idea of control parameters and topological dimension, the asymptotic properties of dynamics, abstract dynamics, the concept of embedding, singular perturbation theory, strange attractor, Fermi-Pasta-Ulam phenomena, an example of computer heuristics, the idea of elementary catastrophe theory and so on were explained. The logistic map is the simplest introduction to complex dynamics. The complicated dynamics is referred to as strange attractors. Two-dimensional maps are the highest dimensional maps commonly studied. These were discussed in detail. (Kako, I.)

System Dynamics

Science.gov (United States)

Morecroft, John

System dynamics is an approach for thinking about and simulating situations and organisations of all kinds and sizes by visualising how the elements fit together, interact and change over time. This chapter, written by John Morecroft, describes modern system dynamics which retains the fundamentals developed in the 1950s by Jay W. Forrester of the MIT Sloan School of Management. It looks at feedback loops and time delays that affect system behaviour in a non-linear way, and illustrates how dynamic behaviour depends upon feedback loop structures. It also recognises improvements as part of the ongoing process of managing a situation in order to achieve goals. Significantly it recognises the importance of context, and practitioner skills. Feedback systems thinking views problems and solutions as being intertwined. The main concepts and tools: feedback structure and behaviour, causal loop diagrams, dynamics, are practically illustrated in a wide variety of contexts from a hot water shower through to a symphony orchestra and the practical application of the approach is described through several real examples of its use for strategic planning and evaluation.

Capturing Dynamics in the Power Grid: Formulation of Dynamic State Estimation through Data Assimilation

Energy Technology Data Exchange (ETDEWEB)

Zhou, Ning [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Zhenyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meng, Da [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elbert, Stephen T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Shaobu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diao, Ruisheng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-03-31

With the increasing complexity resulting from uncertainties and stochastic variations introduced by intermittent renewable energy sources, responsive loads, mobile consumption of plug-in vehicles, and new market designs, more and more dynamic behaviors are observed in everyday power system operation. To operate a power system efficiently and reliably, it is critical to adopt a dynamic paradigm so that effective control actions can be taken in time. The dynamic paradigm needs to include three fundamental components: dynamic state estimation; look-ahead dynamic simulation; and dynamic contingency analysis (Figure 1). These three components answer three basic questions: where the system is; where the system is going; and how secure the system is against accidents. The dynamic state estimation provides a solid cornerstone to support the other 2 components and is the focus of this study.

Spaces of Dynamical Systems

CERN Document Server

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.

Dynamic stiffness of suction caissons

DEFF Research Database (Denmark)

Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

Fractional dynamic calculus and fractional dynamic equations on time scales

CERN Document Server

Georgiev, Svetlin G

2018-01-01

Pedagogically organized, this monograph introduces fractional calculus and fractional dynamic equations on time scales in relation to mathematical physics applications and problems. Beginning with the definitions of forward and backward jump operators, the book builds from Stefan Hilger’s basic theories on time scales and examines recent developments within the field of fractional calculus and fractional equations. Useful tools are provided for solving differential and integral equations as well as various problems involving special functions of mathematical physics and their extensions and generalizations in one and more variables. Much discussion is devoted to Riemann-Liouville fractional dynamic equations and Caputo fractional dynamic equations.  Intended for use in the field and designed for students without an extensive mathematical background, this book is suitable for graduate courses and researchers looking for an introduction to fractional dynamic calculus and equations on time scales. .

Dynamic mechanical behaviors of Fangshan marble

Directory of Open Access Journals (Sweden)

Wei Yao

2017-10-01

Full Text Available Dynamic strength parameters are extensively used in mining engineering and rock mechanics. However, there are no widely accepted dynamic failure models for rocks. In this study, the dynamic punching shear strength, uniaxial compressive strength (UCS and tensile strength of fine-grained Fangshan marble (FM are first measured by using a split Hopkinson pressure bar (SHPB system. The pulse-shaping technique is then implemented to maintain the dynamic force balance in SHPB tests. Experimental results show that the dynamic punching shear strength, UCS and tensile strength increase with the loading rate. A recently developed dynamic Mohr-Coulomb theory is then used to interpret the testing data. In this model, the angle of internal friction ϕ is assumed to be independent of loading rate and is obtained using the static strength values. According to the dynamic Mohr-Coulomb theory, the dynamic UCS and the dynamic tensile strength are predicted from the dynamic punching shear strength. Furthermore, based on this dynamic theory, the dynamic UCS is predicted from the dynamic tensile strength. The consistency between the predicted and measured dynamic strengths demonstrates that the dynamic Mohr-Coulomb theory is applicable to FM.

Fractional Dynamics Applications of Fractional Calculus to Dynamics of Particles, Fields and Media

CERN Document Server

Tarasov, Vasily E

2010-01-01

"Fractional Dynamics: Applications of Fractional Calculus to Dynamics of Particles, Fields and Media" presents applications of fractional calculus, integral and differential equations of non-integer orders in describing systems with long-time memory, non-local spatial and fractal properties. Mathematical models of fractal media and distributions, generalized dynamical systems and discrete maps, non-local statistical mechanics and kinetics, dynamics of open quantum systems, the hydrodynamics and electrodynamics of complex media with non-local properties and memory are considered. This book is intended to meet the needs of scientists and graduate students in physics, mechanics and applied mathematics who are interested in electrodynamics, statistical and condensed matter physics, quantum dynamics, complex media theories and kinetics, discrete maps and lattice models, and nonlinear dynamics and chaos. Dr. Vasily E. Tarasov is a Senior Research Associate at Nuclear Physics Institute of Moscow State University and...

Computational Fluid Dynamics

International Nuclear Information System (INIS)

Myeong, Hyeon Guk

1999-06-01

This book deals with computational fluid dynamics with basic and history of numerical fluid dynamics, introduction of finite volume method using one-dimensional heat conduction equation, solution of two-dimensional heat conduction equation, solution of Navier-Stokes equation, fluid with heat transport, turbulent flow and turbulent model, Navier-Stokes solution by generalized coordinate system such as coordinate conversion, conversion of basic equation, program and example of calculation, application of abnormal problem and high speed solution of numerical fluid dynamics.

Dynamic link: user's manual

International Nuclear Information System (INIS)

Harada, Hiroo; Asai, Kiyoshi; Kihara, Kazuhisa.

1981-09-01

The purpose of dynamic link facility is to link a load module dynamically only when it is used in execution time. The facility is very useful for development, execution and maintenance of a large scale computer program which is too big to be saved as one load module in main memory, or it is poor economy to save it due to many unused subroutines depending on an input. It is also useful for standardization and common utilization of programs. Standard usage of dynamic link facility of FACOM M-200 computer system, a software tool which analyzes the effect of dynamic link facility and application of dynamic link to nuclear codes are described. (author)

Dynamics of Media Attention

NARCIS (Netherlands)

Traag, V.A.; Reinanda, R.; Hicks, J.; van Klinken, G.; Aziz-Alaoui, M.A.; Bertelle, C.; Liu, X.; Olivier, D.

2014-01-01

Studies of human attention dynamics analyses how attention is focused on specific topics, issues or people. In online social media, there are clear signs of exogenous shocks, bursty dynamics, and an exponential or powerlaw lifetime distribution. We here analyse the attention dynamics of traditional

An Investigation of dynamic characteristics of structures subjected to dynamic load from the viewpoint of design

International Nuclear Information System (INIS)

Lee, Hyun Ah; Kim, Yong Il; Park, Gyung Jin; Kang, Byung Soo; Kim, Joo Sung

2006-01-01

All the loads in the real world are dynamic loads and structural optimization under dynamic loads is very difficult. Thus the dynamic loads are often transformed to static loads by dynamic factors, which are believed equivalent to the dynamic loads. However, due to the difference of load characteristics, there can be considerable differences between the results from static and dynamic analyses. When the natural frequency of a structure is high, the dynamic analysis result is similar to that of static analysis due to the small inertia effect on the behavior of the structure. However, if the natural frequency of the structure is low, the inertia effect should not be ignored. then, the behavior of the dynamic system is different from that of the static system. The difference of the two cases can be explained from the relationship between the homogeneous and the particular solutions of the differential equation that governs the behavior of the structure. Through various examples, the difference between the dynamic analysis and the static analysis are shown. Also dynamic response optimization results are compared with the results with static loads transformed from dynamic loads by dynamic factors, which show the necessity of the design considering dynamic loads

Bayesian dynamic mediation analysis.

Science.gov (United States)

Huang, Jing; Yuan, Ying

2017-12-01

Most existing methods for mediation analysis assume that mediation is a stationary, time-invariant process, which overlooks the inherently dynamic nature of many human psychological processes and behavioral activities. In this article, we consider mediation as a dynamic process that continuously changes over time. We propose Bayesian multilevel time-varying coefficient models to describe and estimate such dynamic mediation effects. By taking the nonparametric penalized spline approach, the proposed method is flexible and able to accommodate any shape of the relationship between time and mediation effects. Simulation studies show that the proposed method works well and faithfully reflects the true nature of the mediation process. By modeling mediation effect nonparametrically as a continuous function of time, our method provides a valuable tool to help researchers obtain a more complete understanding of the dynamic nature of the mediation process underlying psychological and behavioral phenomena. We also briefly discuss an alternative approach of using dynamic autoregressive mediation model to estimate the dynamic mediation effect. The computer code is provided to implement the proposed Bayesian dynamic mediation analysis. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The Use of the Dynamic Magnification Factor in the Dynamic ...

African Journals Online (AJOL)

It is a method of practice in dynamic analysis of structures to magnify static ... analysis of four frames using the flexible frame model and the stiffness formulation. Dynamic responses were first obtained by direct analysis as solutions to the set of ...

Interactive Dynamic-System Simulation

CERN Document Server

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

Nonlinear dynamics and complexity

CERN Document Server

Luo, Albert; Fu, Xilin

2014-01-01

This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.

Dynamic heterogeneity in life histories

DEFF Research Database (Denmark)

Tuljapurkar, Shripad; Steiner, Uli; Orzack, Steven Hecht

2009-01-01

or no fixed heterogeneity influences this trait. We propose that dynamic heterogeneity provides a 'neutral' model for assessing the possible role of unobserved 'quality' differences between individuals. We discuss fitness for dynamic life histories, and the implications of dynamic heterogeneity...... generate dynamic heterogeneity: life-history differences produced by stochastic stratum dynamics. We characterize dynamic heterogeneity in a range of species across taxa by properties of the Markov chain: the entropy, which describes the extent of heterogeneity, and the subdominant eigenvalue, which...... distributions of lifetime reproductive success. Dynamic heterogeneity contrasts with fixed heterogeneity: unobserved differences that generate variation between life histories. We show by an example that observed distributions of lifetime reproductive success are often consistent with the claim that little...

Dynamic Pricing

DEFF Research Database (Denmark)

Sharifi, Reza; Anvari-Moghaddam, Amjad; Fathi, S. Hamid

2017-01-01

Dynamic pricing scheme, also known as real-time pricing (RTP), can be more efficient and technically beneficial than the other price-based schemes (such as flat-rate or time-of-use (TOU) pricing) for enabling demand response (DR) actions. Over the past few years, advantages of RTP-based schemes h...... of dynamic pricing can lead to increased willingness of consumers to participate in DR programs which in turn improve the operation of liberalized electricity markets.......Dynamic pricing scheme, also known as real-time pricing (RTP), can be more efficient and technically beneficial than the other price-based schemes (such as flat-rate or time-of-use (TOU) pricing) for enabling demand response (DR) actions. Over the past few years, advantages of RTP-based schemes...

The LHC dynamic aperture

CERN Document Server

Koutchouk, Jean-Pierre

1999-01-01

In 1996, the expected field errors in the dipoles and quadrupoles yielded a long-term dynamic aperture of some 8sigma at injection. The target was set to 12sigma to account for the limitations of our model (imperfections and dynamics). From scaling laws and tracking, a specification for the field imperfections yielding the target dynamic aperture was deduced. The gap between specification and expected errors is being bridged by i) an improvement of the dipole field quality, ii) a balance between geometric and persistent current errors, iii) additional correction circuits (a3 ,b4 ). With the goal in view, the emphasis has now turned to the sensitivity of the dynamic aperture to the optical parameters.The distortion of the dynamics at the lower amplitudes effectively reached by the particles is minimized by optimizing the distribution of the betatron phase advance. At collision energy, the dynamic aperture is limited by the field imperfections of the low-beta triplets, enhanced by the crossing angle. With corre...

Equivalent Dynamic Models.

Science.gov (United States)

Molenaar, Peter C M

2017-01-01

Equivalences of two classes of dynamic models for weakly stationary multivariate time series are discussed: dynamic factor models and autoregressive models. It is shown that exploratory dynamic factor models can be rotated, yielding an infinite set of equivalent solutions for any observed series. It also is shown that dynamic factor models with lagged factor loadings are not equivalent to the currently popular state-space models, and that restriction of attention to the latter type of models may yield invalid results. The known equivalent vector autoregressive model types, standard and structural, are given a new interpretation in which they are conceived of as the extremes of an innovating type of hybrid vector autoregressive models. It is shown that consideration of hybrid models solves many problems, in particular with Granger causality testing.

Solving Dynamic Traveling Salesman Problem Using Dynamic Gaussian Process Regression

Directory of Open Access Journals (Sweden)

Stephen M. Akandwanaho

2014-01-01

Full Text Available This paper solves the dynamic traveling salesman problem (DTSP using dynamic Gaussian Process Regression (DGPR method. The problem of varying correlation tour is alleviated by the nonstationary covariance function interleaved with DGPR to generate a predictive distribution for DTSP tour. This approach is conjoined with Nearest Neighbor (NN method and the iterated local search to track dynamic optima. Experimental results were obtained on DTSP instances. The comparisons were performed with Genetic Algorithm and Simulated Annealing. The proposed approach demonstrates superiority in finding good traveling salesman problem (TSP tour and less computational time in nonstationary conditions.

Introduction to dynamic programming

CERN Document Server

Cooper, Leon; Rodin, E Y

1981-01-01

Introduction to Dynamic Programming provides information pertinent to the fundamental aspects of dynamic programming. This book considers problems that can be quantitatively formulated and deals with mathematical models of situations or phenomena that exists in the real world.Organized into 10 chapters, this book begins with an overview of the fundamental components of any mathematical optimization model. This text then presents the details of the application of dynamic programming to variational problems. Other chapters consider the application of dynamic programming to inventory theory, Mark

Dynamic phase transitions and dynamic phase diagrams of the Ising model on the Shastry-Sutherland lattice

Energy Technology Data Exchange (ETDEWEB)

Deviren, Şeyma Akkaya, E-mail: sadeviren@nevsehir.edu.tr [Department of Science Education, Education Faculty, Nevsehir Hacı Bektaş Veli University, 50300 Nevşehir (Turkey); Deviren, Bayram [Department of Physics, Nevsehir Hacı Bektaş Veli University, 50300 Nevsehir (Turkey)

2016-03-15

The dynamic phase transitions and dynamic phase diagrams are studied, within a mean-field approach, in the kinetic Ising model on the Shastry-Sutherland lattice under the presence of a time varying (sinusoidal) magnetic field by using the Glauber-type stochastic dynamics. The time-dependence behavior of order parameters and the behavior of average order parameters in a period, which is also called the dynamic order parameters, as a function of temperature, are investigated. Temperature dependence of the dynamic magnetizations, hysteresis loop areas and correlations are investigated in order to characterize the nature (first- or second-order) of the dynamic phase transitions as well as to obtain the dynamic phase transition temperatures. We present the dynamic phase diagrams in the magnetic field amplitude and temperature plane. The phase diagrams exhibit a dynamic tricritical point and reentrant phenomena. The phase diagrams also contain paramagnetic (P), Néel (N), Collinear (C) phases, two coexistence or mixed regions, (N+C) and (N+P), which strongly depend on interaction parameters. - Highlights: • Dynamic magnetization properties of spin-1/2 Ising model on SSL are investigated. • Dynamic magnetization, hysteresis loop area, and correlation have been calculated. • The dynamic phase diagrams are constructed in (T/|J|, h/|J|) plane. • The phase diagrams exhibit a dynamic tricritical point and reentrant phenomena.

Unsteady Vibration Aerodynamic Modeling and Evaluation of Dynamic Derivatives Using Computational Fluid Dynamics

Directory of Open Access Journals (Sweden)

Xu Liu

2015-01-01

Full Text Available Unsteady aerodynamic system modeling is widely used to solve the dynamic stability problems encountering aircraft design. In this paper, single degree-of-freedom (SDF vibration model and forced simple harmonic motion (SHM model for dynamic derivative prediction are developed on the basis of modified Etkin model. In the light of the characteristics of SDF time domain solution, the free vibration identification methods for dynamic stability parameters are extended and applied to the time domain numerical simulation of blunted cone calibration model examples. The dynamic stability parameters by numerical identification are no more than 0.15% deviated from those by experimental simulation, confirming the correctness of SDF vibration model. The acceleration derivatives, rotary derivatives, and combination derivatives of Army-Navy Spinner Rocket are numerically identified by using unsteady N-S equation and solving different SHV patterns. Comparison with the experimental result of Army Ballistic Research Laboratories confirmed the correctness of the SHV model and dynamic derivative identification. The calculation result of forced SHM is better than that by the slender body theory of engineering approximation. SDF vibration model and SHM model for dynamic stability parameters provide a solution to the dynamic stability problem encountering aircraft design.

Modeling dynamic swarms

KAUST Repository

Ghanem, Bernard; Ahuja, Narendra

2013-01-01

This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define a DS as a large layout of stochastically repetitive spatial configurations of dynamic objects (swarm elements) whose motions exhibit local spatiotemporal

Basic structural dynamics

CERN Document Server

Anderson, James C

2012-01-01

A concise introduction to structural dynamics and earthquake engineering Basic Structural Dynamics serves as a fundamental introduction to the topic of structural dynamics. Covering single and multiple-degree-of-freedom systems while providing an introduction to earthquake engineering, the book keeps the coverage succinct and on topic at a level that is appropriate for undergraduate and graduate students. Through dozens of worked examples based on actual structures, it also introduces readers to MATLAB, a powerful software for solving both simple and complex structural d

Cooperation guided by the coexistence of imitation dynamics and aspiration dynamics in structured populations

Science.gov (United States)

Xu, Kuangyi; Li, Kun; Cong, Rui; Wang, Long

2017-02-01

In the framework of the evolutionary game theory, two fundamentally different mechanisms, the imitation process and the aspiration-driven dynamics, can be adopted by players to update their strategies. In the former case, individuals imitate the strategy of a more successful peer, while in the latter case individuals change their strategies based on a comparison of payoffs they collect in the game to their own aspiration levels. Here we explore how cooperation evolves for the coexistence of these two dynamics. Intriguingly, cooperation reaches its lowest level when a certain moderate fraction of individuals pick aspiration-level-driven rule while the others choose pairwise comparison rule. Furthermore, when individuals can adjust their update rules besides their strategies, either imitation dynamics or aspiration-driven dynamics will finally take over the entire population, and the stationary cooperation level is determined by the outcome of competition between these two dynamics. We find that appropriate synergetic effects and moderate aspiration level boost the fixation probability of aspiration-driven dynamics most effectively. Our work may be helpful in understanding the cooperative behavior induced by the coexistence of imitation dynamics and aspiration dynamics in the society.

What are System Dynamics Insights?

OpenAIRE

Stave, K.; Zimmermann, N. S.; Kim, H.

2016-01-01

This paper explores the concept of system dynamics insights. In our field, the term “insight” is generally understood to mean dynamic insight, that is, a deep understanding about the relationship between structure and behavior. We argue this is only one aspect of the range of insights possible from system dynamics activities, and describe a broader range of potential system dynamics insights. We also propose an initial framework for discussion that relates different types of system dynamics a...

Mechanisms of dynamic deformation and dynamic failure in aluminum nitride

International Nuclear Information System (INIS)

Hu Guangli; Chen, C.Q.; Ramesh, K.T.; McCauley, J.W.

2012-01-01

Uniaxial quasi-static, uniaxial dynamic and confined dynamic compression experiments have been performed to characterize the failure and deformation mechanisms of a sintered polycrystalline aluminum nitride using a servohydraulic machine and a modified Kolsky bar. Scanning electron microscopy and transmission electron microscopy (TEM) are used to identify the fracture and deformation mechanisms under high rate and high pressure loading conditions. These results show that the fracture mechanisms are strong functions of confining stress and strain rate, with transgranular fracture becoming more common at high strain rates. Dynamic fracture mechanics and micromechanical models are used to analyze the observed fracture mechanisms. TEM characterization of fragments from the confined dynamic experiments shows that at higher pressures dislocation motion becomes a common dominant deformation mechanism in AlN. Prismatic slip is dominant, and pronounced microcrack–dislocation interactions are observed, suggesting that the dislocation plasticity affects the macroscopic fracture behavior in this material under high confining stresses.

A concurrent multiscale micromorphic molecular dynamics

International Nuclear Information System (INIS)

Li, Shaofan; Tong, Qi

2015-01-01

In this work, we have derived a multiscale micromorphic molecular dynamics (MMMD) from first principle to extend the (Andersen)-Parrinello-Rahman molecular dynamics to mesoscale and continuum scale. The multiscale micromorphic molecular dynamics is a con-current three-scale dynamics that couples a fine scale molecular dynamics, a mesoscale micromorphic dynamics, and a macroscale nonlocal particle dynamics together. By choosing proper statistical closure conditions, we have shown that the original Andersen-Parrinello-Rahman molecular dynamics is the homogeneous and equilibrium case of the proposed multiscale micromorphic molecular dynamics. In specific, we have shown that the Andersen-Parrinello-Rahman molecular dynamics can be rigorously formulated and justified from first principle, and its general inhomogeneous case, i.e., the three scale con-current multiscale micromorphic molecular dynamics can take into account of macroscale continuum mechanics boundary condition without the limitation of atomistic boundary condition or periodic boundary conditions. The discovered multiscale scale structure and the corresponding multiscale dynamics reveal a seamless transition from atomistic scale to continuum scale and the intrinsic coupling mechanism among them based on first principle formulation

Dynamics of Financial System: A System Dynamics Approach

OpenAIRE

Girish K. Nair; Lewlyn Lester Raj Rodrigues

2013-01-01

There are several ratios which define the financial health of an organization but the importance of Net cash flow, Gross income, Net income, Pending bills, Receivable bills, Debt, and Book value can never be undermined as they give the exact picture of the financial condition. While there are several approaches to study the dynamics of these variables, system dynamics based modelling and simulation is one of the modern techniques. The paper explores this method to simulate the before mentione...

Essential dynamics and relativity

CERN Document Server

O'Donnell, Peter J

2014-01-01

Essential Dynamics & Relativity provides students with an introduction to the core aspects of dynamics and special relativity. The author reiterates important ideas and terms throughout and covers concepts that are often missing from other textbooks at this level. He also places each topic within the wider constructs of the theory, without jumping from topic to topic to illustrate a point.The first section of the book focuses on dynamics, discussing the basic aspects of single particle motion and analyzing the motion of multi-particle systems. The book also explains the dynamical behavior of b

Dynamics of the diffusive DM-DE interaction – Dynamical system approach

Energy Technology Data Exchange (ETDEWEB)

Haba, Zbigniew [Institute of Theoretical Physics, University of Wroclaw, Plac Maxa Borna 9, 50-204 Wrocław (Poland); Stachowski, Aleksander; Szydłowski, Marek, E-mail: zhab@ift.uni.wroc.pl, E-mail: aleksander.stachowski@uj.edu.pl, E-mail: marek.szydlowski@uj.edu.pl [Astronomical Observatory, Jagiellonian University, Orla 171, 30-244 Krakow (Poland)

2016-07-01

We discuss dynamics of a model of an energy transfer between dark energy (DE) and dark matter (DM) . The energy transfer is determined by a non-conservation law resulting from a diffusion of dark matter in an environment of dark energy. The relativistic invariance defines the diffusion in a unique way. The system can contain baryonic matter and radiation which do not interact with the dark sector. We treat the Friedman equation and the conservation laws as a closed dynamical system. The dynamics of the model is examined using the dynamical systems methods for demonstration how solutions depend on initial conditions. We also fit the model parameters using astronomical observation: SNIa, H ( z ), BAO and Alcock-Paczynski test. We show that the model with diffuse DM-DE is consistent with the data.

Riverine habitat dynamics

Science.gov (United States)

Jacobson, R.B.

2013-01-01

The physical habitat template is a fundamental influence on riverine ecosystem structure and function. Habitat dynamics refers to the variation in habitat through space and time as the result of varying discharge and varying geomorphology. Habitat dynamics can be assessed at spatial scales ranging from the grain (the smallest resolution at which an organism relates to its environment) to the extent (the broadest resolution inclusive of all space occupied during its life cycle). In addition to a potentially broad range of spatial scales, assessments of habitat dynamics may include dynamics of both occupied and nonoccupied habitat patches because of process interactions among patches. Temporal aspects of riverine habitat dynamics can be categorized into hydrodynamics and morphodynamics. Hydrodynamics refers to habitat variation that results from changes in discharge in the absence of significant change of channel morphology and at generally low sediment-transport rates. Hydrodynamic assessments are useful in cases of relatively high flow exceedance (percent of time a flow is equaled or exceeded) or high critical shear stress, conditions that are applicable in many studies of instream flows. Morphodynamics refers to habitat variation resulting from changes to substrate conditions or channel/floodplain morphology. Morphodynamic assessments are necessary when channel and floodplain boundary conditions have been significantly changed, generally by relatively rare flood events or in rivers with low critical shear stress. Morphodynamic habitat variation can be particularly important as disturbance mechanisms that mediate population growth or for providing conditions needed for reproduction, such as channel-migration events that erode cutbanks and provide new pointbar surfaces for germination of riparian trees. Understanding of habitat dynamics is increasing in importance as societal goals shift toward restoration of riverine ecosystems. Effective investment in restoration

Responses of Cloud Type Distributions to the Large-Scale Dynamical Circulation: Water Budget-Related Dynamical Phase Space and Dynamical Regimes

Science.gov (United States)

Wong, Sun; Del Genio, Anthony; Wang, Tao; Kahn, Brian; Fetzer, Eric J.; L'Ecuyer, Tristan S.

2015-01-01

Goals: Water budget-related dynamical phase space; Connect large-scale dynamical conditions to atmospheric water budget (including precipitation); Connect atmospheric water budget to cloud type distributions.

Record dynamics

DEFF Research Database (Denmark)

Robe, Dominic M.; Boettcher, Stefan; Sibani, Paolo

2016-01-01

When quenched rapidly beyond their glass transition, colloidal suspensions fall out of equilibrium. The pace of their dynamics then slows down with the system age, i.e., with the time elapsed after the quench. This breaking of time translational invariance is associated with dynamical observables...... which depend on two time-arguments. The phenomenology is shared by a broad class of aging systems and calls for an equally broad theoretical description. The key idea is that, independent of microscopic details, aging systems progress through rare intermittent structural relaxations that are de......-facto irreversible and become increasingly harder to achieve. Thus, a progression of record-sized dynamical barriers are traversed in the approach to equilibration. Accordingly, the statistics of the events is closely described by a log-Poisson process. Originally developed for relaxation in spin glasses...

Nonlinear dynamics of structures

CERN Document Server

Oller, Sergio

2014-01-01

This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

Dynamics from diffraction

International Nuclear Information System (INIS)

Goodwin, Andrew L.; Tucker, Matthew G.; Cope, Elizabeth R.; Dove, Martin T.; Keen, David A.

2006-01-01

We explore the possibility that detailed dynamical information might be extracted from powder diffraction data. Our focus is a recently reported technique that employs statistical analysis of atomistic configurations to calculate dynamical properties from neutron total scattering data. We show that it is possible to access the phonon dispersion of low-frequency modes using such an approach, without constraining the results in terms of some pre-defined dynamical model. The high-frequency regions of the phonon spectrum are found to be less well preserved in the diffraction data

Fluid dynamics transactions

CERN Document Server

Fiszdon, W

1965-01-01

Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co

Theoretical Fluid Dynamics

CERN Document Server

Shivamoggi, Bhimsen K

1998-01-01

"Although there are many texts and monographs on fluid dynamics, I do not know of any which is as comprehensive as the present book. It surveys nearly the entire field of classical fluid dynamics in an advanced, compact, and clear manner, and discusses the various conceptual and analytical models of fluid flow." - Foundations of Physics on the first edition. Theoretical Fluid Dynamics functions equally well as a graduate-level text and a professional reference. Steering a middle course between the empiricism of engineering and the abstractions of pure mathematics, the author focuses

Dynamic secrets in communication security

CERN Document Server

Xiao, Sheng; Towsley, Donald

2013-01-01

Dynamic secrets are constantly generated and updated from messages exchanged between two communication users. When dynamic secrets are used as a complement to existing secure communication systems, a stolen key or password can be quickly and automatically reverted to its secret status without disrupting communication. 'Dynamic Secrets in Communication Security' presents unique security properties and application studies for this technology. Password theft and key theft no longer pose serious security threats when parties frequently use dynamic secrets. This book also illustrates that a dynamic

Environmental/dynamic mechanical equipment qualification and dynamic electrical equipment qualification program (EDQP)

International Nuclear Information System (INIS)

Hunter, J.A.

1984-01-01

Equipment qualification research is being conducted to investigate acceptable criteria, requirements, and methodologies for the dynamic (including seismic) and environmental qualification of mechanical equipment and for the dynamic (including seismic) qualification of electrical equipment. The program is organized into three elements: (1) General Research, (2) Environmental Research, and (3) Dynamic Research. This paper presents the highlights of the results to date in these three elements of the program

Review of various dynamic modeling methods and development of an intuitive modeling method for dynamic systems

International Nuclear Information System (INIS)

Shin, Seung Ki; Seong, Poong Hyun

2008-01-01

Conventional static reliability analysis methods are inadequate for modeling dynamic interactions between components of a system. Various techniques such as dynamic fault tree, dynamic Bayesian networks, and dynamic reliability block diagrams have been proposed for modeling dynamic systems based on improvement of the conventional modeling methods. In this paper, we review these methods briefly and introduce dynamic nodes to the existing Reliability Graph with General Gates (RGGG) as an intuitive modeling method to model dynamic systems. For a quantitative analysis, we use a discrete-time method to convert an RGGG to an equivalent Bayesian network and develop a software tool for generation of probability tables

Dynamized Preparations in Cell Culture

Directory of Open Access Journals (Sweden)

Ellanzhiyil Surendran Sunila

2009-01-01

Full Text Available Although reports on the efficacy of homeopathic medicines in animal models are limited, there are even fewer reports on the in vitro action of these dynamized preparations. We have evaluated the cytotoxic activity of 30C and 200C potencies of ten dynamized medicines against Dalton's Lymphoma Ascites, Ehrlich's Ascites Carcinoma, lung fibroblast (L929 and Chinese Hamster Ovary (CHO cell lines and compared activity with their mother tinctures during short-term and long-term cell culture. The effect of dynamized medicines to induce apoptosis was also evaluated and we studied how dynamized medicines affected genes expressed during apoptosis. Mother tinctures as well as some dynamized medicines showed significant cytotoxicity to cells during short and long-term incubation. Potentiated alcohol control did not produce any cytotoxicity at concentrations studied. The dynamized medicines were found to inhibit CHO cell colony formation and thymidine uptake in L929 cells and those of Thuja, Hydrastis and Carcinosinum were found to induce apoptosis in DLA cells. Moreover, dynamized Carcinosinum was found to induce the expression of p53 while dynamized Thuja produced characteristic laddering pattern in agarose gel electrophoresis of DNA. These results indicate that dynamized medicines possess cytotoxic as well as apoptosis-inducing properties.

The dynamics of transmission and the dynamics of networks.

Science.gov (United States)

Farine, Damien

2017-05-01

A toy example depicted here highlighting the results of a study in this issue of the Journal of Animal Ecology that investigates the impact of network dynamics on potential disease outbreaks. Infections (stars) that spread by contact only (left) reduce the predicted outbreak size compared to situations where individuals can become infected by moving through areas that previously contained infected individuals (right). This is potentially important in species where individuals, or in this case groups, have overlapping ranges (as depicted on the top right). Incorporating network dynamics that maintain information about the ordering of contacts (central blocks; including the ordering of spatial overlap as noted by the arrows that highlight the blue group arriving after the red group in top-right of the figure) is important for capturing how a disease might not have the opportunity to spread to all individuals. By contrast, a static or 'average' network (lower blocks) does not capture any of these dynamics. Interestingly, although static networks generally predict larger outbreak sizes, the authors find that in cases when transmission probability is low, this prediction can switch as a result of changes in the estimated intensity of contacts among individuals. [Colour figure can be viewed at wileyonlinelibrary.com]. Springer, A., Kappeler, P.M. & Nunn, C.L. (2017) Dynamic vs. static social networks in models of parasite transmission: Predicting Cryptosporidium spread in wild lemurs. Journal of Animal Ecology, 86, 419-433. The spread of disease or information through networks can be affected by several factors. Whether and how these factors are accounted for can fundamentally change the predicted impact of a spreading epidemic. Springer, Kappeler & Nunn () investigate the role of different modes of transmission and network dynamics on the predicted size of a disease outbreak across several groups of Verreaux's sifakas, a group-living species of lemur. While some factors

Combining molecular dynamics with mesoscopic Green’s function reaction dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Vijaykumar, Adithya, E-mail: vijaykumar@amolf.nl [FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands); van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam (Netherlands); Bolhuis, Peter G. [van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam (Netherlands); Rein ten Wolde, Pieter, E-mail: p.t.wolde@amolf.nl [FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands)

2015-12-07

In many reaction-diffusion processes, ranging from biochemical networks, catalysis, to complex self-assembly, the spatial distribution of the reactants and the stochastic character of their interactions are crucial for the macroscopic behavior. The recently developed mesoscopic Green’s Function Reaction Dynamics (GFRD) method enables efficient simulation at the particle level provided the microscopic dynamics can be integrated out. Yet, many processes exhibit non-trivial microscopic dynamics that can qualitatively change the macroscopic behavior, calling for an atomistic, microscopic description. We propose a novel approach that combines GFRD for simulating the system at the mesoscopic scale where particles are far apart, with a microscopic technique such as Langevin dynamics or Molecular Dynamics (MD), for simulating the system at the microscopic scale where reactants are in close proximity. This scheme defines the regions where the particles are close together and simulated with high microscopic resolution and those where they are far apart and simulated with lower mesoscopic resolution, adaptively on the fly. The new multi-scale scheme, called MD-GFRD, is generic and can be used to efficiently simulate reaction-diffusion systems at the particle level.

Combining molecular dynamics with mesoscopic Green’s function reaction dynamics simulations

International Nuclear Information System (INIS)

Vijaykumar, Adithya; Bolhuis, Peter G.; Rein ten Wolde, Pieter

2015-01-01

In many reaction-diffusion processes, ranging from biochemical networks, catalysis, to complex self-assembly, the spatial distribution of the reactants and the stochastic character of their interactions are crucial for the macroscopic behavior. The recently developed mesoscopic Green’s Function Reaction Dynamics (GFRD) method enables efficient simulation at the particle level provided the microscopic dynamics can be integrated out. Yet, many processes exhibit non-trivial microscopic dynamics that can qualitatively change the macroscopic behavior, calling for an atomistic, microscopic description. We propose a novel approach that combines GFRD for simulating the system at the mesoscopic scale where particles are far apart, with a microscopic technique such as Langevin dynamics or Molecular Dynamics (MD), for simulating the system at the microscopic scale where reactants are in close proximity. This scheme defines the regions where the particles are close together and simulated with high microscopic resolution and those where they are far apart and simulated with lower mesoscopic resolution, adaptively on the fly. The new multi-scale scheme, called MD-GFRD, is generic and can be used to efficiently simulate reaction-diffusion systems at the particle level

On the Theory of Nonlinear Dynamics and its Applications in Vehicle Systems Dynamics

DEFF Research Database (Denmark)

True, Hans

1999-01-01

We present a brief outline of nonlinear dynamics and its applications to vehicle systems dynamics problems. The concept of a phase space is introduced in order to illustrate the dynamics of nonlinear systems in a way that is easy to perceive. Various equilibrium states are defined...... of nonlinear dynamics in vehicle simulations is discussed, and it is argued that it is necessary to know the equilibrium states of the full nonlinear system before the simulation calculations are performed......., and the important case of multiple equilibrium states and their dependence on a parameter is discussed. It is argued that the analysis of nonlinear dynamic problems always should start with an analysis of the equilibrium states of the full nonlinear problem whereby great care must be taken in the choice...

Control of dynamical localization

International Nuclear Information System (INIS)

Gong Jiangbin; Woerner, Hans Jakob; Brumer, Paul

2003-01-01

Control over the quantum dynamics of chaotic kicked rotor systems is demonstrated. Specifically, control over a number of quantum coherent phenomena is achieved by a simple modification of the kicking field. These include the enhancement of the dynamical localization length, the introduction of classical anomalous diffusion assisted control for systems far from the semiclassical regime, and the observation of a variety of strongly nonexponential line shapes for dynamical localization. The results provide excellent examples of controlled quantum dynamics in a system that is classically chaotic and offer opportunities to explore quantum fluctuations and correlations in quantum chaos

Gas-Phase Molecular Dynamics: Theoretical Studies in Spectroscopy and Chemical Dynamics

Energy Technology Data Exchange (ETDEWEB)

Yu, H.G.; Muckerman, J.T.

2010-06-01

The goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods.

Plasma turbulence. Structure formation, selection rule, dynamic response and dynamics transport

International Nuclear Information System (INIS)

Ito, Sanae I.

2010-01-01

The five-year project of Grant-in-Aid for Specially Promoted Research entitled general research on the structure formation and selection rule in plasma turbulence had brought many outcomes. Based on these outcomes, the Grant-in-Aid for Scientific Research (S) program entitled general research on dynamic response and dynamic transport in plasma turbulence has started. In the present paper, the state-of-the-art of the research activities on the structure formation, selection rule and dynamics in plasma turbulence are reviewed with reference to outcomes of these projects. (author)

Liquid Sloshing Dynamics

Science.gov (United States)

Ibrahim, Raouf A.

2005-06-01

The problem of liquid sloshing in moving or stationary containers remains of great concern to aerospace, civil, and nuclear engineers; physicists; designers of road tankers and ship tankers; and mathematicians. Beginning with the fundamentals of liquid sloshing theory, this book takes the reader systematically from basic theory to advanced analytical and experimental results in a self-contained and coherent format. The book is divided into four sections. Part I deals with the theory of linear liquid sloshing dynamics; Part II addresses the nonlinear theory of liquid sloshing dynamics, Faraday waves, and sloshing impacts; Part III presents the problem of linear and nonlinear interaction of liquid sloshing dynamics with elastic containers and supported structures; and Part IV considers the fluid dynamics in spinning containers and microgravity sloshing. This book will be invaluable to researchers and graduate students in mechanical and aeronautical engineering, designers of liquid containers, and applied mathematicians.

Microsoft Dynamics GP 2013 implementation

CERN Document Server

Yudin, Victoria

2013-01-01

A step-by-step guide for planning and carrying out your Microsoft Dynamics GP 2013 implementation. Detailed descriptions and illustrations of setup screens and practical examples and advice are included for the Dynamics GP system and core modules.If you are a new or existing Microsoft Dynamics GP consultant or an end user who wants to implement, install, and set up core modules of Dynamics GP 2013, then this book is for you. A basic understanding of business management systems and either Dynamics GP or a similar application is recommended.

Equivalence of Brownian dynamics and dynamic Monte Carlo simulations in multicomponent colloidal suspensions.

Science.gov (United States)

Cuetos, Alejandro; Patti, Alessandro

2015-08-01

We propose a simple but powerful theoretical framework to quantitatively compare Brownian dynamics (BD) and dynamic Monte Carlo (DMC) simulations of multicomponent colloidal suspensions. By extending our previous study focusing on monodisperse systems of rodlike colloids, here we generalize the formalism described there to multicomponent colloidal mixtures and validate it by investigating the dynamics in isotropic and liquid crystalline phases containing spherical and rodlike particles. In order to investigate the dynamics of multicomponent colloidal systems by DMC simulations, it is key to determine the elementary time step of each species and establish a unique timescale. This is crucial to consistently study the dynamics of colloidal particles with different geometry. By analyzing the mean-square displacement, the orientation autocorrelation functions, and the self part of the van Hove correlation functions, we show that DMC simulation is a very convenient and reliable technique to describe the stochastic dynamics of any multicomponent colloidal system. Our theoretical formalism can be easily extended to any colloidal system containing size and/or shape polydisperse particles.

Quantumness-generating capability of quantum dynamics

Science.gov (United States)

Li, Nan; Luo, Shunlong; Mao, Yuanyuan

2018-04-01

We study quantumness-generating capability of quantum dynamics, where quantumness refers to the noncommutativity between the initial state and the evolving state. In terms of the commutator of the square roots of the initial state and the evolving state, we define a measure to quantify the quantumness-generating capability of quantum dynamics with respect to initial states. Quantumness-generating capability is absent in classical dynamics and hence is a fundamental characteristic of quantum dynamics. For qubit systems, we present an analytical form for this measure, by virtue of which we analyze several prototypical dynamics such as unitary dynamics, phase damping dynamics, amplitude damping dynamics, and random unitary dynamics (Pauli channels). Necessary and sufficient conditions for the monotonicity of quantumness-generating capability are also identified. Finally, we compare these conditions for the monotonicity of quantumness-generating capability with those for various Markovianities and illustrate that quantumness-generating capability and quantum Markovianity are closely related, although they capture different aspects of quantum dynamics.

Cortico-cortical communication dynamics

Directory of Open Access Journals (Sweden)

Per E Roland

2014-05-01

Full Text Available IIn principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG, and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review.

Dynamics of aesthetic appreciation

Science.gov (United States)

Carbon, Claus-Christian

2012-03-01

Aesthetic appreciation is a complex cognitive processing with inherent aspects of cold as well as hot cognition. Research from the last decades of empirical has shown that evaluations of aesthetic appreciation are highly reliable. Most frequently, facial attractiveness was used as the corner case for investigating aesthetic appreciation. Evaluating facial attractiveness shows indeed high internal consistencies and impressively high inter-rater reliabilities, even across cultures. Although this indicates general and stable mechanisms underlying aesthetic appreciation, it is also obvious that our taste for specific objects changes dynamically. Aesthetic appreciation on artificial object categories, such as fashion, design or art is inherently very dynamic. Gaining insights into the cognitive mechanisms that trigger and enable corresponding changes of aesthetic appreciation is of particular interest for research as this will provide possibilities to modeling aesthetic appreciation for longer durations and from a dynamic perspective. The present paper refers to a recent two-step model ("the dynamical two-step-model of aesthetic appreciation"), dynamically adapting itself, which accounts for typical dynamics of aesthetic appreciation found in different research areas such as art history, philosophy and psychology. The first step assumes singular creative sources creating and establishing innovative material towards which, in a second step, people adapt by integrating it into their visual habits. This inherently leads to dynamic changes of the beholders' aesthetic appreciation.

Intramolecular and nonlinear dynamics

Energy Technology Data Exchange (ETDEWEB)

Davis, M.J. [Argonne National Laboratory, IL (United States)

1993-12-01

Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

Space dynamics

International Nuclear Information System (INIS)

Corno, S.E.

1995-01-01

Analytical methods for Space Dynamics of fission reactors, are presented. It is shown how a few sample problems in space dynamics can be solved, within the one and two group diffusion model, by purely analytical tools, essentially based on Laplace transform and complex Green function techniques. A quite suggestive generalization of this approach, applicable to the fluid core reactors, whose fuel is undergoing a violent mixing, is reported and briefly discussed. (author)

Dynamic covalent surfactants

NARCIS (Netherlands)

Minkenberg, C.B.

2012-01-01

In this thesis the development of surfactant aggregates with fast exchange dynamics between the aggregated and non-aggregated state is described. Dynamic surfactant exchange plays an important role in natural systems, for instance in cell signaling, cell division, and uptake and release of cargo.

Dynamical supersymmetry breaking

International Nuclear Information System (INIS)

Affleck, I.

1985-03-01

Supersymmetry, and in particular, dynamical supersymmetry breaking, offers the hope of a natural solution of the gauge hierarchy problem in grand unification. I briefly review recent work on dynamical supersymmetry breaking in four-dimensional Higgs theories and its application to grand unified model building

Dynamic combinatorial chemistry

NARCIS (Netherlands)

Otto, Sijbren; Furlan, Ricardo L.E.; Sanders, Jeremy K.M.

2002-01-01

A combinatorial library that responds to its target by increasing the concentration of strong binders at the expense of weak binders sounds ideal. Dynamic combinatorial chemistry has the potential to achieve exactly this. In this review, we will highlight the unique features that distinguish dynamic

Discrete Dynamics Lab

Science.gov (United States)

Wuensche, Andrew

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

Dynamics in Complex Coacervates

Science.gov (United States)

Perry, Sarah

Understanding the dynamics of a material provides detailed information about the self-assembly, structure, and intermolecular interactions present in a material. While rheological methods have long been used for the characterization of complex coacervate-based materials, it remains a challenge to predict the dynamics for a new system of materials. Furthermore, most work reports only qualitative trends exist as to how parameters such as charge stoichiometry, ionic strength, and polymer chain length impact self-assembly and material dynamics, and there is little information on the effects of polymer architecture or the organization of charges within a polymer. We seek to link thermodynamic studies of coacervation phase behavior with material dynamics through a carefully-controlled, systematic study of coacervate linear viscoelasticity for different polymer chemistries. We couple various methods of characterizing the dynamics of polymer-based complex coacervates, including the time-salt superposition methods developed first by Spruijt and coworkers to establish a more mechanistic strategy for comparing the material dynamics and linear viscoelasticity of different systems. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research.

Dynamic CT in the abdominal organ, 2. Dynamics in the abdominal malignancies

Energy Technology Data Exchange (ETDEWEB)

Fukuda, K [Jikei Univ., Tokyo (Japan). School of Medicine

1980-03-01

The potential role of the abdominal dynamic CT in malignant tumors was evaluated. Among total of 112 cases dynamically studied included were, 22 cases of abdominal malignancies, renal cell carcinoma in 7, hepatocellular carcinoma in 7, metastatic liver tumor in 5, renal pelvic carcinoma in 2, and pancreatic cystadenocarcinoma in one. The results led to the following advantages of the abdominal dynamic CT over conventional CT. (1) The tumor thrombus and the lymphnode involvement could be better demonstrated. (2) The tumor vessels and the tumor stain could be depicted. (3) The extent of the tumor in the parenchyma could be better appreciated. The more invasive catheter angiography would likely to be replaced by the abdominal dynamic CT in the selected case.

Nonlinear dynamics and astrophysics

International Nuclear Information System (INIS)

Vallejo, J. C.; Sanjuan, M. A. F.

2000-01-01

Concepts and techniques from Nonlinear Dynamics, also known as Chaos Theory, have been applied successfully to several astrophysical fields such as orbital motion, time series analysis or galactic dynamics, providing answers to old questions but also opening a few new ones. Some of these topics are described in this review article, showing the basis of Nonlinear Dynamics, and how it is applied in Astrophysics. (Author)

Dynamic fracture characterization of material

International Nuclear Information System (INIS)

Kobayashi, A.S.; Emery, A.F.; Liaw, B.M.

1981-01-01

The influences of a wide range of material properties, i.e. of A533B steel, a silicon nitride ceramic and a Homalite-100 photoelastic polymer, as well as the influences of the specimen sizes on the dynamic fracture response of fracture specimens are presented in this paper. The results of a numerical study show that the dynamic fracture responses of these fracture specimens of proportional dimensions were indistinguishable provided the normalized dynamic fracture toughness versus normalized crack velocity relations of the three materials coincide. The limited results suggest that should the normalized dynamic fracture toughness versus normalized crack velocity relations between prototype and model materials coincide, then dynamic fracture experiments on scaled models can be used to infer the dynamic fracture response of the prototype. (orig./HP)

Protein dynamics by neutron scattering: The protein dynamical transition and the fragile-to-strong dynamical crossover in hydrated lysozyme

International Nuclear Information System (INIS)

Magazù, Salvatore; Migliardo, Federica; Benedetto, Antonio; Vertessy, Beata

2013-01-01

Highlights: • The role played by the instrumental energy resolution in neutron scattering is presented. • The effect of natural bioprotectants on protein dynamics is shown. • A connection between the protein dynamical transition and the fragile-to-strong dynamical crossover is formulated. - Abstract: In this work Elastic Incoherent Neutron Scattering (EINS) results on lysozyme water mixtures in absence and in presence of bioprotectant systems are presented. The EINS data have been collected by using the IN13 and the IN10 spectrometers at the Institut Laue-Langevin (ILL, Grenoble, France) allowing to evaluate the temperature behaviour of the mean square displacement and of the relaxation time for the investigated systems. The obtained experimental findings together with theoretical calculations allow to put into evidence the role played by the spectrometer resolution and to clarify the connexion between the registered protein dynamical transition, the system relaxation time, and the instrumental energy resolution

Operational Dynamic Configuration Analysis

Science.gov (United States)

Lai, Chok Fung; Zelinski, Shannon

2010-01-01

Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified

Algorithm for simulation of quantum many-body dynamics using dynamical coarse-graining

International Nuclear Information System (INIS)

Khasin, M.; Kosloff, R.

2010-01-01

An algorithm for simulation of quantum many-body dynamics having su(2) spectrum-generating algebra is developed. The algorithm is based on the idea of dynamical coarse-graining. The original unitary dynamics of the target observables--the elements of the spectrum-generating algebra--is simulated by a surrogate open-system dynamics, which can be interpreted as weak measurement of the target observables, performed on the evolving system. The open-system state can be represented by a mixture of pure states, localized in the phase space. The localization reduces the scaling of the computational resources with the Hilbert-space dimension n by factor n 3/2 (ln n) -1 compared to conventional sparse-matrix methods. The guidelines for the choice of parameters for the simulation are presented and the scaling of the computational resources with the Hilbert-space dimension of the system is estimated. The algorithm is applied to the simulation of the dynamics of systems of 2x10 4 and 2x10 6 cold atoms in a double-well trap, described by the two-site Bose-Hubbard model.

Structural Dynamics

International Nuclear Information System (INIS)

Kim, Du Gi

2005-08-01

This book introduces summary of structural dynamics, the reason of learning of structural dynamics, single-degree of freedom system, simple harmonic vibration and application, numerical analysis method, such as time domain and frequency domain and nonlinear system, multi-degree of freedom system random vibration over discrete distribution, continuous distribution and extreme value distribution, circumstance vibration, earth quake vibration, including input earthquake, and earthquake-resistant design and capacity spectrum method, wind oscillation wave vibration, vibration control and maintenance control.

Dynamic Speaking Assessments

Science.gov (United States)

Hill, Kent; Sabet, Mehran

2009-01-01

This article describes an attempt to adopt dynamic assessment (DA) methods in classroom speaking assessments. The study reported in this article focused on four particular applications of dynamic speaking assessment (DSA). The first, "mediated assistance" (MA), involves interaction between an assistor and a learner to reveal problems in…

Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners

Directory of Open Access Journals (Sweden)

Martin Kirchberger

2016-02-01

Full Text Available Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings.

Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners

Science.gov (United States)

Kirchberger, Martin

2016-01-01

Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings. PMID:26868955

Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners.

Science.gov (United States)

Kirchberger, Martin; Russo, Frank A

2016-02-10

Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings. © The Author(s) 2016.

Dynamic magnetic hysteresis behavior and dynamic phase transition in the spin-1 Blume-Capel model

Energy Technology Data Exchange (ETDEWEB)

Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2012-03-15

The nature (time variation) of response magnetization m(wt) of the spin-1 Blume-Capel model in the presence of a periodically varying external magnetic field h(wt) is studied by employing the effective-field theory (EFT) with correlations as well as the Glauber-type stochastic dynamics. We determine the time variations of m(wt) and h(wt) for various temperatures, and investigate the dynamic magnetic hysteresis behavior. We also investigate the temperature dependence of the dynamic magnetization, hysteresis loop area and correlation near the transition point in order to characterize the nature (first- or second-order) of the dynamic transitions as well as obtain the dynamic phase transition temperatures. The hysteresis loops are obtained for different reduced temperatures and we find that the areas of the loops are decreasing with the increasing of the reduced temperatures. We also present the dynamic phase diagrams and compare the results of the EFT with the results of the dynamic mean-field approximation. The phase diagrams exhibit many dynamic critical points, such as tricritical ( Bullet ), zero-temperature critical (Z), triple (TP) and multicritical (A) points. According to values of Hamiltonian parameters, besides the paramagnetic (P), ferromagnetic (F) fundamental phases, one coexistence or mixed phase region, (F+P) and the reentrant behavior exist in the system. The results are in good agreement with some experimental and theoretical results. - Highlights: Black-Right-Pointing-Pointer Kinetic spin-1 Blume-Capel model is studied using the effective-field theory. Black-Right-Pointing-Pointer We investigated the dynamic magnetic hysteresis behavior. Black-Right-Pointing-Pointer Dynamic magnetization, hysteresis loop area and correlation are investigated. Black-Right-Pointing-Pointer System exhibits tricritical, zero-temperature, triple and multicritical points. Black-Right-Pointing-Pointer We present the dynamic phase diagrams and compare the results of the EFT

Vehicle Dynamics and Control

CERN Document Server

Rajamani, Rajesh

2012-01-01

Vehicle Dynamics and Control provides a comprehensive coverage of vehicle control systems and the dynamic models used in the development of these control systems. The control system applications covered in the book include cruise control, adaptive cruise control, ABS, automated lane keeping, automated highway systems, yaw stability control, engine control, passive, active and semi-active suspensions, tire-road friction coefficient estimation, rollover prevention, and hybrid electric vehicle. In developing the dynamic model for each application, an effort is made to both keep the model simple enough for control system design but at the same time rich enough to capture the essential features of the dynamics. A special effort has been made to explain the several different tire models commonly used in literature and to interpret them physically. In the second edition of the book, chapters on roll dynamics, rollover prevention and hybrid electric vehicles have been added, and the chapter on electronic stability co...

the use of the dynamic magnification factor in the dynamic analysis

African Journals Online (AJOL)

Uncle Greg 4 Real

bridges and some country's codes of practice made specifications in respect of the dynamic magnification factor for the analysis and design of various types of structures subjected to ... span. For example the United kingdom code. [10] presented dynamic magnification factors, related ... For SDOF (Single Degree of Freedom).

Dynamics of unstable systems

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)

Dynamics of glassy systems

International Nuclear Information System (INIS)

Cugliandolo, Leticia F.

2003-09-01

These lecture notes can be read in two ways. The first two Sections contain a review of the phenomenology of several physical systems with slow nonequilibrium dynamics. In the Conclusions we summarize the scenario for this temporal evolution derived from the solution to some solvable models (p spin and the like) that are intimately connected to the mode coupling approach (and similar ones) to super-cooled liquids. At the end we list a number of open problems of great relevance in this context. These Sections can be read independently of the body of the paper where we present some of the basic analytic techniques used to study the out of equilibrium dynamics of classical and quantum models with and without disorder. We start the technical part by briefly discussing the role played by the environment and by introducing and comparing its representation in the equilibrium and dynamic treatment of classical and quantum systems. We next explain the role played by explicit quenched disorder in both approaches. Later on we focus on analytical techniques; we expand on the dynamic functional methods, and the diagrammatic expansions and resummations used to derive macroscopic equations from the microscopic dynamics. We show why the macroscopic dynamic equations for disordered models and those resulting from self-consistent approximations to non-disordered ones coincide. We review some generic properties of dynamic systems evolving out of equilibrium like the modifications of the fluctuation-dissipation theorem, generic scaling forms of the correlation functions, etc. Finally we solve a family of mean-field models. The connection between the dynamic treatment and the analysis of the free-energy landscape of these models is also presented. We use pedagogical examples all along these lectures to illustrate the properties and results. (author)

Hamiltonian dynamics of preferential attachment

International Nuclear Information System (INIS)

Zuev, Konstantin; Papadopoulos, Fragkiskos; Krioukov, Dmitri

2016-01-01

Prediction and control of network dynamics are grand-challenge problems in network science. The lack of understanding of fundamental laws driving the dynamics of networks is among the reasons why many practical problems of great significance remain unsolved for decades. Here we study the dynamics of networks evolving according to preferential attachment (PA), known to approximate well the large-scale growth dynamics of a variety of real networks. We show that this dynamics is Hamiltonian, thus casting the study of complex networks dynamics to the powerful canonical formalism, in which the time evolution of a dynamical system is described by Hamilton’s equations. We derive the explicit form of the Hamiltonian that governs network growth in PA. This Hamiltonian turns out to be nearly identical to graph energy in the configuration model, which shows that the ensemble of random graphs generated by PA is nearly identical to the ensemble of random graphs with scale-free degree distributions. In other words, PA generates nothing but random graphs with power-law degree distribution. The extension of the developed canonical formalism for network analysis to richer geometric network models with non-degenerate groups of symmetries may eventually lead to a system of equations describing network dynamics at small scales. (paper)

Dynamic critical behaviour and scaling

International Nuclear Information System (INIS)

Oezoguz, B.E.

2001-01-01

Traditionally the scaling is the property of dynamical systems at thermal equilibrium. In second order phase transitions scaling behaviour is due to the infinite correlation length around the critical point. In first order phase transitions however, the correlation length remains finite and a different type of scaling can be observed. For first order phase transitions all singularities are governed by the volume of the system. Recently, a different type of scaling, namely dynamic scaling has attracted attention in second order phase transitions. In dynamic scaling, when a system prepared at high temperature is quenched to the critical temperature, it exhibits scaling behaviour. Dynamic scaling has been applied to various spin systems and the validity of the arguments are shown. Firstly, in this thesis project the dynamic scaling is applied to 4-dimensional using spin system which exhibits second order phase transition with mean-field critical indices. Secondly, it is shown that although the dynamic is quite different, first order phase transitions also has a different type of dynamic scaling

Global Analysis of Nonlinear Dynamics

CERN Document Server

Luo, Albert

2012-01-01

Global Analysis of Nonlinear Dynamics collects chapters on recent developments in global analysis of non-linear dynamical systems with a particular emphasis on cell mapping methods developed by Professor C.S. Hsu of the University of California, Berkeley. This collection of contributions prepared by a diverse group of internationally recognized researchers is intended to stimulate interests in global analysis of complex and high-dimensional nonlinear dynamical systems, whose global properties are largely unexplored at this time. This book also: Presents recent developments in global analysis of non-linear dynamical systems Provides in-depth considerations and extensions of cell mapping methods Adopts an inclusive style accessible to non-specialists and graduate students Global Analysis of Nonlinear Dynamics is an ideal reference for the community of nonlinear dynamics in different disciplines including engineering, applied mathematics, meteorology, life science, computational science, and medicine.  

Instantaneous and dynamical decoherence

Science.gov (United States)

Polonyi, Janos

2018-04-01

Two manifestations of decoherence, called instantaneous and dynamical, are investigated. The former reflects the suppression of the interference between the components of the current state while the latter reflects that within the initial state. These types of decoherence are computed in the case of the Brownian motion and the harmonic and anharmonic oscillators within the semiclassical approximation. A remarkable phenomenon, namely the opposite orientation of the time arrow of the dynamical variables compared to that of the quantum fluctuations generates a double exponential time dependence of the dynamical decoherence in the presence of a harmonic force. For the weakly anharmonic oscillator the dynamical decoherence is found to depend in a singular way on the amount of the anharmonicity.

Astrophysical fluid dynamics

Science.gov (United States)

Ogilvie, Gordon I.

2016-06-01

> These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.

Modeling dynamic swarms

KAUST Repository

Ghanem, Bernard

2013-01-01

This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define a DS as a large layout of stochastically repetitive spatial configurations of dynamic objects (swarm elements) whose motions exhibit local spatiotemporal interdependency and stationarity, i.e., the motions are similar in any small spatiotemporal neighborhood. Examples of DS abound in nature, e.g., herds of animals and flocks of birds. To capture the local spatiotemporal properties of the DS, we present a probabilistic model that learns both the spatial layout of swarm elements (based on low-level image segmentation) and their joint dynamics that are modeled as linear transformations. To this end, a spatiotemporal neighborhood is associated with each swarm element, in which local stationarity is enforced both spatially and temporally. We assume that the prior on the swarm dynamics is distributed according to an MRF in both space and time. Embedding this model in a MAP framework, we iterate between learning the spatial layout of the swarm and its dynamics. We learn the swarm transformations using ICM, which iterates between estimating these transformations and updating their distribution in the spatiotemporal neighborhoods. We demonstrate the validity of our method by conducting experiments on real and synthetic video sequences. Real sequences of birds, geese, robot swarms, and pedestrians evaluate the applicability of our model to real world data. © 2012 Elsevier Inc. All rights reserved.

System overview and walking dynamics of a passive dynamic walking robot with flat feet

Directory of Open Access Journals (Sweden)

Xinyu Liu

2015-12-01

Full Text Available The concept of “passive dynamic walking robot” refers to the robot that can walk down a shallow slope stably without any actuation and control which shows a limit cycle during walking. By adding actuation at some joints, the passive dynamic walking robot can walk stably on level ground and exhibit more versatile gaits than fully passive robot, namely, the “limit cycle walker.” In this article, we present the mechanical structures and control system design for a passive dynamic walking robot with series elastic actuators at hip joint and ankle joints. We built a walking model that consisted of an upper body, knee joints, and flat feet and derived its walking dynamics that involve double stance phases in a walking cycle based on virtual power principle. The instant just before impact was chosen as the start of one step to reduce the number of independent state variables. A numerical simulation was implemented by using MATLAB, in which the proposed passive dynamic walking model could walk stably down a shallow slope, which proves that the derived walking dynamics are correct. A physical passive robot prototype was built finally, and the experiment results show that by only simple control scheme the passive dynamic robot could walk stably on level ground.

Assessing the Dynamic Behavior of Online Q&A Knowledge Markets: A System Dynamics Approach

Science.gov (United States)

Jafari, Mostafa; Hesamamiri, Roozbeh; Sadjadi, Jafar; Bourouni, Atieh

2012-01-01

Purpose: The objective of this paper is to propose a holistic dynamic model for understanding the behavior of a complex and internet-based kind of knowledge market by considering both social and economic interactions. Design/methodology/approach: A system dynamics (SD) model is formulated in this study to investigate the dynamic characteristics of…

Multiscale simulations of anisotropic particles combining molecular dynamics and Green's function reaction dynamics

Science.gov (United States)

Vijaykumar, Adithya; Ouldridge, Thomas E.; ten Wolde, Pieter Rein; Bolhuis, Peter G.

2017-03-01

The modeling of complex reaction-diffusion processes in, for instance, cellular biochemical networks or self-assembling soft matter can be tremendously sped up by employing a multiscale algorithm which combines the mesoscopic Green's Function Reaction Dynamics (GFRD) method with explicit stochastic Brownian, Langevin, or deterministic molecular dynamics to treat reactants at the microscopic scale [A. Vijaykumar, P. G. Bolhuis, and P. R. ten Wolde, J. Chem. Phys. 143, 214102 (2015)]. Here we extend this multiscale MD-GFRD approach to include the orientational dynamics that is crucial to describe the anisotropic interactions often prevalent in biomolecular systems. We present the novel algorithm focusing on Brownian dynamics only, although the methodology is generic. We illustrate the novel algorithm using a simple patchy particle model. After validation of the algorithm, we discuss its performance. The rotational Brownian dynamics MD-GFRD multiscale method will open up the possibility for large scale simulations of protein signalling networks.

Dynamic Bifurcations

CERN Document Server

1991-01-01

Dynamical Bifurcation Theory is concerned with the phenomena that occur in one parameter families of dynamical systems (usually ordinary differential equations), when the parameter is a slowly varying function of time. During the last decade these phenomena were observed and studied by many mathematicians, both pure and applied, from eastern and western countries, using classical and nonstandard analysis. It is the purpose of this book to give an account of these developments. The first paper, by C. Lobry, is an introduction: the reader will find here an explanation of the problems and some easy examples; this paper also explains the role of each of the other paper within the volume and their relationship to one another. CONTENTS: C. Lobry: Dynamic Bifurcations.- T. Erneux, E.L. Reiss, L.J. Holden, M. Georgiou: Slow Passage through Bifurcation and Limit Points. Asymptotic Theory and Applications.- M. Canalis-Durand: Formal Expansion of van der Pol Equation Canard Solutions are Gevrey.- V. Gautheron, E. Isambe...

Dynamic wall demonstration project

Energy Technology Data Exchange (ETDEWEB)

Nakatsui, L.; Mayhew, W.

1990-12-01

The dynamic wall concept is a ventilation strategy that can be applied to a single family dwelling. With suitable construction, outside air can be admitted through the exterior walls of the house to the interior space to function as ventilation air. The construction and performance monitoring of a demonstration house built to test the dynamic wall concept in Sherwood Park, Alberta, is described. The project had the objectives of demonstrating and assessing the construction methods; determining the cost-effectiveness of the concept in Alberta; analyzing the operation of the dynamic wall system; and determining how other components and systems in the house interact with the dynamic wall. The exterior wall construction consisted of vinyl siding, spun-bonded polyolefin-backed (SBPO) rigid fiberglass sheathing, 38 mm by 89 mm framing, fiberglass batt insulation and 12.7 mm drywall. The mechanical system was designed to operate in the dynamic (negative pressure) mode, however flexibility was provided to allow operation in the static (balanced pressure) mode to permit monitoring of the walls as if they were in a conventional house. The house was monitored by an extensive computerized monitoring system. Dynamic wall operation was dependent on pressure and temperature differentials between indoor and outdoor as well as wind speed and direction. The degree of heat gain was found to be ca 74% of the indoor-outdoor temperature differential. Temperature of incoming dynamic air was significantly affected by solar radiation and measurement of indoor air pollutants found no significant levels. 4 refs., 34 figs., 11 tabs.

On melting dynamics and the glass transition. II. Glassy dynamics as a melting process.

Science.gov (United States)

Krzakala, Florent; Zdeborová, Lenka

2011-01-21

There are deep analogies between the melting dynamics in systems with a first-order phase transition and the dynamics from equilibrium in super-cooled liquids. For a class of Ising spin models undergoing a first-order transition--namely p-spin models on the so-called Nishimori line--it can be shown that the melting dynamics can be exactly mapped to the equilibrium dynamics. In this mapping the dynamical--or mode-coupling--glass transition corresponds to the spinodal point, while the Kauzmann transition corresponds to the first-order phase transition itself. Both in mean field and finite dimensional models this mapping provides an exact realization of the random first-order theory scenario for the glass transition. The corresponding glassy phenomenology can then be understood in the framework of a standard first-order phase transition.

Dynamics robustness of cascading systems.

Directory of Open Access Journals (Sweden)

Jonathan T Young

2017-03-01

Full Text Available A most important property of biochemical systems is robustness. Static robustness, e.g., homeostasis, is the insensitivity of a state against perturbations, whereas dynamics robustness, e.g., homeorhesis, is the insensitivity of a dynamic process. In contrast to the extensively studied static robustness, dynamics robustness, i.e., how a system creates an invariant temporal profile against perturbations, is little explored despite transient dynamics being crucial for cellular fates and are reported to be robust experimentally. For example, the duration of a stimulus elicits different phenotypic responses, and signaling networks process and encode temporal information. Hence, robustness in time courses will be necessary for functional biochemical networks. Based on dynamical systems theory, we uncovered a general mechanism to achieve dynamics robustness. Using a three-stage linear signaling cascade as an example, we found that the temporal profiles and response duration post-stimulus is robust to perturbations against certain parameters. Then analyzing the linearized model, we elucidated the criteria of when signaling cascades will display dynamics robustness. We found that changes in the upstream modules are masked in the cascade, and that the response duration is mainly controlled by the rate-limiting module and organization of the cascade's kinetics. Specifically, we found two necessary conditions for dynamics robustness in signaling cascades: 1 Constraint on the rate-limiting process: The phosphatase activity in the perturbed module is not the slowest. 2 Constraints on the initial conditions: The kinase activity needs to be fast enough such that each module is saturated even with fast phosphatase activity and upstream changes are attenuated. We discussed the relevance of such robustness to several biological examples and the validity of the above conditions therein. Given the applicability of dynamics robustness to a variety of systems, it

RADYBAN: A tool for reliability analysis of dynamic fault trees through conversion into dynamic Bayesian networks

International Nuclear Information System (INIS)

Montani, S.; Portinale, L.; Bobbio, A.; Codetta-Raiteri, D.

2008-01-01

In this paper, we present RADYBAN (Reliability Analysis with DYnamic BAyesian Networks), a software tool which allows to analyze a dynamic fault tree relying on its conversion into a dynamic Bayesian network. The tool implements a modular algorithm for automatically translating a dynamic fault tree into the corresponding dynamic Bayesian network and exploits classical algorithms for the inference on dynamic Bayesian networks, in order to compute reliability measures. After having described the basic features of the tool, we show how it operates on a real world example and we compare the unreliability results it generates with those returned by other methodologies, in order to verify the correctness and the consistency of the results obtained

Finite temperature dynamics of a Holstein polaron: The thermo-field dynamics approach

Science.gov (United States)

Chen, Lipeng; Zhao, Yang

2017-12-01

Combining the multiple Davydov D2 Ansatz with the method of thermo-field dynamics, we study finite temperature dynamics of a Holstein polaron on a lattice. It has been demonstrated, using the hierarchy equations of motion method as a benchmark, that our approach provides an efficient, robust description of finite temperature dynamics of the Holstein polaron in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. The method of thermo-field dynamics handles temperature effects in the Hilbert space with key numerical advantages over other treatments of finite-temperature dynamics based on quantum master equations in the Liouville space or wave function propagation with Monte Carlo importance sampling. While for weak to moderate diagonal coupling temperature increases inhibit polaron mobility, it is found that off-diagonal coupling induces phonon-assisted transport that dominates at high temperatures. Results on the mean square displacements show that band-like transport features dominate the diagonal coupling cases, and there exists a crossover from band-like to hopping transport with increasing temperature when including off-diagonal coupling. As a proof of concept, our theory provides a unified treatment of coherent and incoherent transport in molecular crystals and is applicable to any temperature.

The Dynamical Invariant of Open Quantum System

OpenAIRE

Wu, S. L.; Zhang, X. Y.; Yi, X. X.

2015-01-01

The dynamical invariant, whose expectation value is constant, is generalized to open quantum system. The evolution equation of dynamical invariant (the dynamical invariant condition) is presented for Markovian dynamics. Different with the dynamical invariant for the closed quantum system, the evolution of the dynamical invariant for the open quantum system is no longer unitary, and the eigenvalues of it are time-dependent. Since any hermitian operator fulfilling dynamical invariant condition ...

Dynamical clockwork axions

Science.gov (United States)

Coy, Rupert; Frigerio, Michele; Ibe, Masahiro

2017-10-01

The clockwork mechanism is a novel method for generating a large separation between the dynamical scale and interaction scale of a theory. We demonstrate how the mechanism can arise from a sequence of strongly-coupled sectors. This framework avoids elementary scalar fields as well as ad hoc continuous global symmetries, both of which are subject to serious stability issues. The clockwork factor, q, is determined by the consistency of the strong dynamics. The preserved global U(1) of the clockwork appears as an accidental symmetry, resulting from discrete or U(1) gauge symmetries, and it is spontaneously broken by the chiral condensates. We apply such a dynamical clockwork to construct models with an effectively invisible QCD axion from TeV-scale strong dynamics. The axion couplings are determined by the localisation of the Standard Model interactions along the clockwork sequence. The TeV spectrum includes either coloured hadrons or vector-like quarks. Dark matter can be accounted for by the axion or the lightest neutral baryons, which are accidentally stable.

Structure, Reactivity and Dynamics

Indian Academy of Sciences (India)

Understanding structure, reactivity and dynamics is the core issue in chemical ... functional theory (DFT) calculations, molecular dynamics (MD) simulations, light- ... between water and protein oxygen atoms, the superionic conductors which ...

Geometry from dynamics, classical and quantum

CERN Document Server

Cariñena, José F; Marmo, Giuseppe; Morandi, Giuseppe

2015-01-01

This book describes, by using elementary techniques, how some geometrical structures widely used today in many areas of physics, like symplectic, Poisson, Lagrangian, Hermitian, etc., emerge from dynamics. It is assumed that what can be accessed in actual experiences when studying a given system is just its dynamical behavior that is described by using a family of variables ("observables" of the system).   The book departs from the principle that ''dynamics is first'', and then tries to answer in what sense the sole dynamics determines the geometrical structures that have proved so useful to describe the dynamics in so many important instances. In this vein it is shown that most of the geometrical structures that are used in the standard presentations of classical dynamics (Jacobi, Poisson, symplectic, Hamiltonian, Lagrangian) are determined, though in general not uniquely, by the dynamics alone. The same program is accomplished for the geometrical structures relevant to describe quantum dynamics.  Finall...

Solar array flight dynamic experiment

Science.gov (United States)

Schock, Richard W.

1987-01-01

The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures' dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-41D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

Structure and dynamics of photosynthetic proteins studied by neutron scattering and molecular dynamic simulation

International Nuclear Information System (INIS)

Dellerue, Serge

2000-01-01

Understand the structure-dynamics-function relation in the case of proteins is essential. But few experimental techniques allow to have access to knowledge of fast internal movements of biological macromolecules. With the neutron scattering method, it has been possible to study the reorientation dynamics of side chains and of polypeptide skeleton for two proteins in terms of water or detergent and of temperature. With the use of the molecular dynamics method, essential for completing and interpreting the experimental data, it has been possible to assess the different contributions of the whole structure of proteins to the overall dynamics. It has been shown that the polypeptide skeleton presents an energy relaxation comparable to those of the side chains. Moreover, it has been explained that the protein dynamics can only be understood in terms of relaxation time distribution. (author) [fr

Constraint Embedding for Vehicle Suspension Dynamics

Directory of Open Access Journals (Sweden)

Jain Abhinandan

2016-06-01

Full Text Available The goal of this research is to achieve close to real-time dynamics performance for allowing auto-pilot in-the-loop testing of unmanned ground vehicles (UGV for urban as well as off-road scenarios. The overall vehicle dynamics performance is governed by the multibody dynamics model for the vehicle, the wheel/terrain interaction dynamics and the onboard control system. The topic of this paper is the development of computationally efficient and accurate dynamics model for ground vehicles with complex suspension dynamics. A challenge is that typical vehicle suspensions involve closed-chain loops which require expensive DAE integration techniques. In this paper, we illustrate the use the alternative constraint embedding technique to reduce the cost and improve the accuracy of the dynamics model for the vehicle.

Nonlinear dynamics aspects of particle accelerators

International Nuclear Information System (INIS)

Jowett, J.M.; Turner, S.; Month, M.

1986-01-01

These proceedings contain the lectures presented at the named winter school. They deal with the application of dynamical systems to accelerator theory. Especially considered are the statistical description of charged-beam plasmas, integrable and nonintegrable Hamiltonian systems, single particle dynamics and nonlinear resonances in circular accelerators, nonlinear dynamics aspects of modern storage rings, nonlinear beam-beam resonances, synchro-betatron resonances, observations of the beam-beam interactions, the dynamics of the beam-beam interactions, beam-beam simulations, the perturbation method in nonlinear dynamics, theories of statistical equilibrium in electron-positron storage rings, nonlinear dissipative phenomena in electron storage rings, the dynamical aperture, the transition to chaos for area-preserving maps, special processors for particle tracking, algorithms for tracking of charged particles in circular accelerators, the breakdown of stability, and a personal perspective of nonlinear dynamics. (HSI)

Dynamic MR imaging of pituitary adenoma

International Nuclear Information System (INIS)

Miki, Yukio; Nishizawa, Sadahiko; Kuroda, Yasumasa; Keyaki, Atsushi; Nabeshima, Sachio; Kawamura, Junichiro; Matsuo, Michimasa

1990-01-01

The authors performed serial dynamic MR imaging in patients with 10 normal pituitary and 21 pituitary adenoma utilizing spin-echo sequence with a very short repetition time (SE 100/15) every minute immediately after a bolus injection of Gd-DTPA. Usual T 1 -weighted images (SE 600/15) were also obtained before and after the dynamic study. Pituitary adenomas included 10 adenomas confirmed by surgery, 4 adenomas confirmed by biologic data, and 7 postoperative adenomas. Out of 10 patients who underwent surgery after dynamic MRI, 9 patients underwent postoperative dynamic MRI. In normal patients, the pituitary gland was markedly enhanced on the early-phase images of the dynamic study, followed by gradual decrease of intensity throughout the dynamic study. In cases of microadenomas, the contrast between the normal pituitary gland and adenoma is better than that on the usual T 1 -weighted images by marked enhancement of the normal pituitary gland. Dynamic images clearly showed the residual normal pituitary glands in all cases of macroadenoma larger than 15 mm in diameter, whereas usual contrast-enhanced images showed the normal pituitary gland only in one case. In all patients who underwent both preoperative and postoperative dynamic MRI, postoperative dynamic MRI showed the normal pituitary glands which are markedly enhanced on the early-phase images in the sites which correspond to the preoperative dynamic study. The normal residual anterior gland was also visualized in four out of 7 patients who received only postoperative dynamic MRI. Dynamic MRI is a strong diagnostic modality for visualizing microadenoma and for visualizing the normal pituitary gland in cases of preoperative and postoperative macroadenoma. (author)

Summary: Hadron dynamics sessions

International Nuclear Information System (INIS)

Carroll, A.S.; Londergan, J.T.

1993-01-01

Four sessions on Hadron Dynamics were organized at this Workshop. The first topic, QCD Exclusive Reactions and Color Transparency, featured talks by Ralston, Heppelman and Strikman; the second, QCD and Inclusive Reactions had talks by Garvey, Speth and Kisslinger. The third dynamics session, Medium Modification of Elementary Interactions had contributions from Kopeliovich, Alves and Gyulassy; the fourth session Pre-QCD Dynamics and Scattering, had talks by Harris, Myhrer and Brown. An additional joint Spectroscopy/Dynamics session featured talks by Zumbro, Johnson and McClelland. These contributions are reviewed briefly in this summary. Two additional joint sessions between Dynamics and η physics are reviewed by the organizers of the Eta sessions. In such a brief review there is no way the authors can adequately summarize the details of the physics presented here. As a result, they concentrate only on brief impressionistic sketches of the physics topics discussed and their interrelations. They include no bibliography in this summary, but simply refer to the talks given in more detail in the Workshop proceedings. They focus on topics which were common to several presentations in these sessions. First, nuclear and particle descriptions of phenomena are now clearly converging, in both a qualitative and quantitative sense; they show several examples of this convergence. Second, an important issue in hadron dynamics is the extent to which elementary interactions are modified in nuclei at high energies and/or densities, and they illustrate some of these medium effects. Finally, they focus on those dynamical issues where hadron facilities can make an important, or even a unique, contribution to the knowledge of particle and nuclear physics

The Dynamics of Costly Signaling

Directory of Open Access Journals (Sweden)

Elliott O. Wagner

2013-04-01

Full Text Available Costly signaling is a mechanism through which the honesty of signals can be secured in equilibrium, even in interactions where communicators have conflicting interests. This paper explores the dynamics of one such signaling game: Spence’s model of education. It is found that separating equilibria are unlikely to emerge under either the replicator or best response dynamics, but that partially communicative mixed equilibria are quite important dynamically. These mixtures are Lyapunov stable in the replicator dynamic and asymptotically stable in the best response dynamic. Moreover, they have large basins of attraction, in fact larger than those of either pooling or separating equilibria. This suggests that these mixtures may play significant, and underappreciated, roles in the explanation of the emergence and stability of information transfer.

Constraint Embedding for Vehicle Suspension Dynamics

OpenAIRE

Jain Abhinandan; Kuo Calvin; Jayakumar Paramsothy; Cameron Jonathan

2016-01-01

The goal of this research is to achieve close to real-time dynamics performance for allowing auto-pilot in-the-loop testing of unmanned ground vehicles (UGV) for urban as well as off-road scenarios. The overall vehicle dynamics performance is governed by the multibody dynamics model for the vehicle, the wheel/terrain interaction dynamics and the onboard control system. The topic of this paper is the development of computationally efficient and accurate dynamics model for ground vehicles with ...

An individual-based model of Zebrafish population dynamics accounting for energy dynamics

DEFF Research Database (Denmark)

Beaudouin, Remy; Goussen, Benoit; Piccini, Benjamin

2015-01-01

Developing population dynamics models for zebrafish is crucial in order to extrapolate from toxicity data measured at the organism level to biological levels relevant to support and enhance ecological risk assessment. To achieve this, a dynamic energy budget for individual zebrafish (DEB model...

Glassy Dynamics

DEFF Research Database (Denmark)

Jensen, Henrik J.; Sibani, Paolo

2007-01-01

The term glassy dynamics is often used to refer to the extremely slow relaxation observed in several types of many component systems. The time span needed to reach a steady, time independent, state will typically be far beyond experimentally accessible time scales. When melted alloys are cooled...... down they typically do not enter a crystalline ordered state. Instead the atoms retain the amorphous arrangement characteristic of the liquid high temperature phase while the mobility of the molecules decreases very many orders of magnitude. This colossal change in the characteristic dynamical time...

Record Statistics and Dynamics

DEFF Research Database (Denmark)

Sibani, Paolo; Jensen, Henrik J.

2009-01-01

with independent random increments. The term record dynamics covers the rather new idea that records may, in special situations, have measurable dynamical consequences. The approach applies to the aging dynamics of glasses and other systems with multiple metastable states. The basic idea is that record sizes...... fluctuations of e. g. the energy are able to push the system past some sort of ‘edge of stability’, inducing irreversible configurational changes, whose statistics then closely follows the statistics of record fluctuations....

Dynamic gamma knife radiosurgery

International Nuclear Information System (INIS)

Luan Shuang; Swanson, Nathan; Chen Zhe; Ma Lijun

2009-01-01

Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C(TM) and Perfexion(TM) units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can obtain a family of plans representing a tradeoff between the delivery time and

Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics

Energy Technology Data Exchange (ETDEWEB)

Yu H. G.; Muckerman, J.T.

2012-05-29

The main goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods, and extends them to understand some important properties of materials in condensed phases and interstellar medium as well as in combustion environments.

Algebraic dynamics solutions and algebraic dynamics algorithm for nonlinear ordinary differential equations

Institute of Scientific and Technical Information of China (English)

WANG; Shunjin; ZHANG; Hua

2006-01-01

The problem of preserving fidelity in numerical computation of nonlinear ordinary differential equations is studied in terms of preserving local differential structure and approximating global integration structure of the dynamical system.The ordinary differential equations are lifted to the corresponding partial differential equations in the framework of algebraic dynamics,and a new algorithm-algebraic dynamics algorithm is proposed based on the exact analytical solutions of the ordinary differential equations by the algebraic dynamics method.In the new algorithm,the time evolution of the ordinary differential system is described locally by the time translation operator and globally by the time evolution operator.The exact analytical piece-like solution of the ordinary differential equations is expressd in terms of Taylor series with a local convergent radius,and its finite order truncation leads to the new numerical algorithm with a controllable precision better than Runge Kutta Algorithm and Symplectic Geometric Algorithm.

Dynamic Analysis of Planar 3-RRR Flexible Parallel Robots with Dynamic Stiffening

Directory of Open Access Journals (Sweden)

Qinghua Zhang

2014-01-01

Full Text Available In consideration of the second-order coupling quantity of the axial displacement caused by the transverse displacement of flexible beam, the first-order approximation coupling model of planar 3-RRR flexible parallel robots is presented, in which the rigid body motion constraints, elastic deformation motion constraints, and dynamic constraints of the moving platform are considered. Based on the different speed of the moving platform, numerical simulation results using the conventional zero-order approximation coupling model and the proposed firstorder approximation coupling model show that the effect of “dynamic stiffening” term on dynamic characteristics of the system is insignificant and can be neglected, and the zero-order approximation coupling model is enough precisely for catching essentially dynamic characteristics of the system. Then, the commercial software ANSYS 13.0 is used to confirm the validity of the zero-order approximation coupling model.

Self-Supervised Dynamical Systems

Science.gov (United States)

Zak, Michail

2003-01-01

Some progress has been made in a continuing effort to develop mathematical models of the behaviors of multi-agent systems known in biology, economics, and sociology (e.g., systems ranging from single or a few biomolecules to many interacting higher organisms). Living systems can be characterized by nonlinear evolution of probability distributions over different possible choices of the next steps in their motions. One of the main challenges in mathematical modeling of living systems is to distinguish between random walks of purely physical origin (for instance, Brownian motions) and those of biological origin. Following a line of reasoning from prior research, it has been assumed, in the present development, that a biological random walk can be represented by a nonlinear mathematical model that represents coupled mental and motor dynamics incorporating the psychological concept of reflection or self-image. The nonlinear dynamics impart the lifelike ability to behave in ways and to exhibit patterns that depart from thermodynamic equilibrium. Reflection or self-image has traditionally been recognized as a basic element of intelligence. The nonlinear mathematical models of the present development are denoted self-supervised dynamical systems. They include (1) equations of classical dynamics, including random components caused by uncertainties in initial conditions and by Langevin forces, coupled with (2) the corresponding Liouville or Fokker-Planck equations that describe the evolutions of probability densities that represent the uncertainties. The coupling is effected by fictitious information-based forces, denoted supervising forces, composed of probability densities and functionals thereof. The equations of classical mechanics represent motor dynamics that is, dynamics in the traditional sense, signifying Newton s equations of motion. The evolution of the probability densities represents mental dynamics or self-image. Then the interaction between the physical and

Ansatz for dynamical hierarchies

DEFF Research Database (Denmark)

Rasmussen, S.; Baas, N.A.; Mayer, B.

2001-01-01

Complex, robust functionalities can be generated naturally in at least two ways: by the assembly of structures and by the evolution of structures. This work is concerned with spontaneous formation of structures. We define the notion of dynamical hierarchies in natural systems and show...... the importance of this particular kind of organization for living systems. We then define a framework that enables us to formulate, investigate, and manipulate such dynamical hierarchies. This framework allows us to simultaneously investigate different levels of description together with them interrelationship...... three. Formulating this system as a simple two-dimensional molecular dynamics (MD) lattice gas allows us within one dynamical system to demonstrate the successive emergence of two higher levels (three levels all together) of robust structures with associated properties. Second, we demonstrate how...

Chunking Dynamics: Heteroclinics in Mind

Directory of Open Access Journals (Sweden)

Mikhail I Rabinovich

2014-03-01

Full Text Available Recent results of imaging technologies and nonlinear dynamics make possible to relate the structure and dynamics of functional brain networks to different mental tasks and to build theoretical models for the description and prediction of cognitive activity. Such models are nonlinear dynamical descriptions of the interaction of the core components –brain modes– participating in a specific mental function. The dynamical images of different mental processes depend on their temporal features. The dynamics of many cognitive functions are transient. They are often observed as a chain of sequentially changing metastable states. A stable heteroclinic channel consisting of chain of saddles -metastable states- connected by unstable separatrices is a mathematical image for robust transients. In this paper we focus on hierarchical chunking dynamics that can represent several forms of transient cognitive activity. Chunking is a dynamical phenomenon that nature uses to perform information processing of long sequences by dividing them in shorter information items. Chunking, for example, makes more efficient the use of short-term memory by breaking up long strings of information (like in language where one can see the separation of a novel on chapters, paragraphs, sentences and finally words. Chunking is important in many processes of perception, learning and cognition in humans and animals. Based on anatomical information about the hierarchical organization of functional brain networks, we proposed here a cognitive network architecture that hierarchically chunks and super-chunks switching sequences of metastable states produced by winnerless competitive heteroclinic dynamics.

Dynamic and reduced-dynamic precise orbit determination of satellites in low earth orbits

International Nuclear Information System (INIS)

Swatschina, P.

2009-01-01

The precise positioning of satellites in Low Earth Orbits (LEO) has become a key technology for advanced space missions. Dedicated satellite missions, such as CHAMP, GRACE and GOCE, that aim to map the Earths gravity field and its variation over time with unprecedented accuracy, initiated the demand for highly precise orbit solutions of LEO satellites. Furthermore, a wide range of additional science opportunities opens up with the capability to generate accurate LEO orbits. For all considered satellite missions, the primary measurement system for navigation is a spaceborne GPS receiver. The goal of this thesis is to establish and implement methods for Precise Orbit Determination (POD) of LEO satellites using GPS. Striving for highest precision using yet efficient orbit generation strategies, the attained orbit solutions are aimed to be competitive with the most advanced solutions of other institutions. Dynamic and reduced-dynamic orbit models provide the basic concepts of this work. These orbit models are subsequently adjusted to the highly accurate GPS measurements. The GPS measurements are introduced at the zero difference level in the ionosphere free linear combination. Appropriate procedures for GPS data screening and editing are established to detect erroneous data and to employ measurements of good quality only. For the dynamic orbit model a sophisticated force model, especially designed for LEO satellites, has been developed. In order to overcome the limitations that are induced by the deficiencies of the purely dynamical model, two different types of empirical parameters are introduced into the force model. These reduced-dynamic orbit models allow for the generation of much longer orbital arcs while preserving the spacecraft dynamics to the most possible extent. The two methods for reduced-dynamic orbit modeling are instantaneous velocity changes (pulses) or piecewise constant accelerations. For both techniques highly efficient modeling algorithms are

Dynamical fermions in lattice quantum chromodynamics

Energy Technology Data Exchange (ETDEWEB)

Szabo, Kalman

2007-07-01

The thesis presentS results in Quantum Chromo Dynamics (QCD) with dynamical lattice fermions. The topological susceptibilty in QCD is determined, the calculations are carried out with dynamical overlap fermions. The most important properties of the quark-gluon plasma phase of QCD are studied, for which dynamical staggered fermions are used. (orig.)

Dynamical fermions in lattice quantum chromodynamics

International Nuclear Information System (INIS)

Szabo, Kalman

2007-01-01

The thesis presentS results in Quantum Chromo Dynamics (QCD) with dynamical lattice fermions. The topological susceptibilty in QCD is determined, the calculations are carried out with dynamical overlap fermions. The most important properties of the quark-gluon plasma phase of QCD are studied, for which dynamical staggered fermions are used. (orig.)

Dynamic Shannon Coding

OpenAIRE

Gagie, Travis

2005-01-01

We present a new algorithm for dynamic prefix-free coding, based on Shannon coding. We give a simple analysis and prove a better upper bound on the length of the encoding produced than the corresponding bound for dynamic Huffman coding. We show how our algorithm can be modified for efficient length-restricted coding, alphabetic coding and coding with unequal letter costs.

Dynamic CT of hepatocellular carcinoma

Energy Technology Data Exchange (ETDEWEB)

Fujita, Nobuyuki; Shirato, Hiroki; Shinohara, Masahiro; Miyasaka, Kazuo; Morita, Yutaka; Irie, Goro

1983-03-01

We performed dynamic CT in 30 cases of hepatocellular carcinoma, and concluded as below. Detecting the stain in the early phase of the dynamic series, it is possible to make a diagnosis of hepatocellular carcinoma. The dynamic CT is effective in a case of small hepatocellular carcinoma in which it is difficult to gain an accurate diagnosis in the routine CT study. The dynamic CT is also effective in the differential diagnosis of hepatic lesions, as other hepatic lesions such as hemangioma and metastatic liver cancer show different patterns compared with hepatocellular carcinoma.

Approximate but accurate quantum dynamics from the Mori formalism: I. Nonequilibrium dynamics

Energy Technology Data Exchange (ETDEWEB)

Montoya-Castillo, Andrés, E-mail: am3720@columbia.edu; Reichman, David R., E-mail: drr2103@columbia.edu [Department of Chemistry, Columbia University, New York, New York 10027 (United States)

2016-05-14

We present a formalism that explicitly unifies the commonly used Nakajima-Zwanzig approach for reduced density matrix dynamics with the more versatile Mori theory in the context of nonequilibrium dynamics. Employing a Dyson-type expansion to circumvent the difficulty of projected dynamics, we obtain a self-consistent equation for the memory kernel which requires only knowledge of normally evolved auxiliary kernels. To illustrate the properties of the current approach, we focus on the spin-boson model and limit our attention to the use of a simple and inexpensive quasi-classical dynamics, given by the Ehrenfest method, for the calculation of the auxiliary kernels. For the first time, we provide a detailed analysis of the dependence of the properties of the memory kernels obtained via different projection operators, namely, the thermal (Redfield-type) and population based (NIBA-type) projection operators. We further elucidate the conditions that lead to short-lived memory kernels and the regions of parameter space to which this program is best suited. Via a thorough analysis of the different closures available for the auxiliary kernels and the convergence properties of the self-consistently extracted memory kernel, we identify the mechanisms whereby the current approach leads to a significant improvement over the direct usage of standard semi- and quasi-classical dynamics.

Approximate but accurate quantum dynamics from the Mori formalism: I. Nonequilibrium dynamics

International Nuclear Information System (INIS)

Montoya-Castillo, Andrés; Reichman, David R.

2016-01-01

We present a formalism that explicitly unifies the commonly used Nakajima-Zwanzig approach for reduced density matrix dynamics with the more versatile Mori theory in the context of nonequilibrium dynamics. Employing a Dyson-type expansion to circumvent the difficulty of projected dynamics, we obtain a self-consistent equation for the memory kernel which requires only knowledge of normally evolved auxiliary kernels. To illustrate the properties of the current approach, we focus on the spin-boson model and limit our attention to the use of a simple and inexpensive quasi-classical dynamics, given by the Ehrenfest method, for the calculation of the auxiliary kernels. For the first time, we provide a detailed analysis of the dependence of the properties of the memory kernels obtained via different projection operators, namely, the thermal (Redfield-type) and population based (NIBA-type) projection operators. We further elucidate the conditions that lead to short-lived memory kernels and the regions of parameter space to which this program is best suited. Via a thorough analysis of the different closures available for the auxiliary kernels and the convergence properties of the self-consistently extracted memory kernel, we identify the mechanisms whereby the current approach leads to a significant improvement over the direct usage of standard semi- and quasi-classical dynamics.

Forecasting house prices in the 50 states using Dynamic Model Averaging and Dynamic Model Selection

DEFF Research Database (Denmark)

Bork, Lasse; Møller, Stig Vinther

2015-01-01

We examine house price forecastability across the 50 states using Dynamic Model Averaging and Dynamic Model Selection, which allow for model change and parameter shifts. By allowing the entire forecasting model to change over time and across locations, the forecasting accuracy improves substantia......We examine house price forecastability across the 50 states using Dynamic Model Averaging and Dynamic Model Selection, which allow for model change and parameter shifts. By allowing the entire forecasting model to change over time and across locations, the forecasting accuracy improves...

The rediscovery of industrial dynamics: the contribution of system dynamics to supply chain management in a dynamic and fragmented world

NARCIS (Netherlands)

Akkermans, H.A.; Dellaert, N.P.

2005-01-01

The field of supply chain management (SCM) almost started with the publication of Forrester's Industrial Dynamics, but it seems that the relevance of this seminal publication for the field of system dynamics has never been so relevant for the field of SCM than today. In this introduction to the

Fundamentals of gas dynamics

CERN Document Server

Babu, V

2014-01-01

Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav

Parity horizons in shape dynamics

International Nuclear Information System (INIS)

Herczeg, Gabriel

2016-01-01

I introduce the notion of a parity horizon, and show that many simple solutions of shape dynamics possess them. I show that the event horizons of the known asymptotically flat black hole solutions of shape dynamics are parity horizons and that this notion of parity implies that these horizons possess a notion of CPT invariance that can in some cases be extended to the solution as a whole. I present three new solutions of shape dynamics with parity horizons and find that not only do event horizons become parity horizons in shape dynamics, but observer-dependent horizons and Cauchy horizons do as well. The fact that Cauchy horizons become (singular) parity horizons suggests a general chronology protection mechanism in shape dynamics that prevents the formation of closed timelike curves. (paper)

Magnetic field induced dynamical chaos.

Science.gov (United States)

Ray, Somrita; Baura, Alendu; Bag, Bidhan Chandra

2013-12-01

In this article, we have studied the dynamics of a particle having charge in the presence of a magnetic field. The motion of the particle is confined in the x-y plane under a two dimensional nonlinear potential. We have shown that constant magnetic field induced dynamical chaos is possible even for a force which is derived from a simple potential. For a given strength of the magnetic field, initial position, and velocity of the particle, the dynamics may be regular, but it may become chaotic when the field is time dependent. Chaotic dynamics is very often if the field is time dependent. Origin of chaos has been explored using the Hamiltonian function of the dynamics in terms of action and angle variables. Applicability of the present study has been discussed with a few examples.

Detecting subnetwork-level dynamic correlations.

Science.gov (United States)

Yan, Yan; Qiu, Shangzhao; Jin, Zhuxuan; Gong, Sihong; Bai, Yun; Lu, Jianwei; Yu, Tianwei

2017-01-15

The biological regulatory system is highly dynamic. The correlations between many functionally related genes change over different biological conditions. Finding dynamic relations on the existing biological network may reveal important regulatory mechanisms. Currently no method is available to detect subnetwork-level dynamic correlations systematically on the genome-scale network. Two major issues hampered the development. The first is gene expression profiling data usually do not contain time course measurements to facilitate the analysis of dynamic relations, which can be partially addressed by using certain genes as indicators of biological conditions. Secondly, it is unclear how to effectively delineate subnetworks, and define dynamic relations between them. Here we propose a new method named LANDD (Liquid Association for Network Dynamics Detection) to find subnetworks that show substantial dynamic correlations, as defined by subnetwork A is concentrated with Liquid Association scouting genes for subnetwork B. The method produces easily interpretable results because of its focus on subnetworks that tend to comprise functionally related genes. Also, the collective behaviour of genes in a subnetwork is a much more reliable indicator of underlying biological conditions compared to using single genes as indicators. We conducted extensive simulations to validate the method's ability to detect subnetwork-level dynamic correlations. Using a real gene expression dataset and the human protein-protein interaction network, we demonstrate the method links subnetworks of distinct biological processes, with both confirmed relations and plausible new functional implications. We also found signal transduction pathways tend to show extensive dynamic relations with other functional groups. The R package is available at https://cran.r-project.org/web/packages/LANDD CONTACTS: yunba@pcom.edu, jwlu33@hotmail.com or tianwei.yu@emory.eduSupplementary information: Supplementary data

Branner-Hubbard Motions and attracting dynamics

DEFF Research Database (Denmark)

Petersen, Carsten Lunde; Tan, Lei

2006-01-01

We introduce a new notion of attracting dynamics, which is related to polynomial-like mappings. Also we review the Branner-Hubbard Motion and study its action on attracting dynamics.......We introduce a new notion of attracting dynamics, which is related to polynomial-like mappings. Also we review the Branner-Hubbard Motion and study its action on attracting dynamics....

Branner-Hubbard motions and attracting dynamics

DEFF Research Database (Denmark)

Petersen, Carsten Lunde; Tan, Lei

We introduce the new notion an aatracting dynamics, which is related to polynomial-likke mappings. Also we review the Branner-Hubbard motion and study its action on attracting dynamics.......We introduce the new notion an aatracting dynamics, which is related to polynomial-likke mappings. Also we review the Branner-Hubbard motion and study its action on attracting dynamics....

Vehicle systems: coupled and interactive dynamics analysis

Science.gov (United States)

Vantsevich, Vladimir V.

2014-11-01

This article formulates a new direction in vehicle dynamics, described as coupled and interactive vehicle system dynamics. Formalised procedures and analysis of case studies are presented. An analytical consideration, which explains the physics of coupled system dynamics and its consequences for dynamics of a vehicle, is given for several sets of systems including: (i) driveline and suspension of a 6×6 truck, (ii) a brake mechanism and a limited slip differential of a drive axle and (iii) a 4×4 vehicle steering system and driveline system. The article introduces a formal procedure to turn coupled system dynamics into interactive dynamics of systems. A new research direction in interactive dynamics of an active steering and a hybrid-electric power transmitting unit is presented and analysed to control power distribution between the drive axles of a 4×4 vehicle. A control strategy integrates energy efficiency and lateral dynamics by decoupling dynamics of the two systems thus forming their interactive dynamics.

Dynamical zeta functions and dynamical determinants for hyperbolic maps a functional approach

CERN Document Server

Baladi, Viviane

2018-01-01

The spectra of transfer operators associated to dynamical systems, when acting on suitable Banach spaces, contain key information about the ergodic properties of the systems. Focusing on expanding and hyperbolic maps, this book gives a self-contained account on the relation between zeroes of dynamical determinants, poles of dynamical zeta functions, and the discrete spectra of the transfer operators. In the hyperbolic case, the first key step consists in constructing a suitable Banach space of anisotropic distributions. The first part of the book is devoted to the easier case of expanding endomorphisms, showing how the (isotropic) function spaces relevant there can be studied via Paley–Littlewood decompositions, and allowing easier access to the construction of the anisotropic spaces which is performed in the second part. This is the first book describing the use of anisotropic spaces in dynamics. Aimed at researchers and graduate students, it presents results and techniques developed since the beginning of...

Dynamic Information Encoding With Dynamic Synapses in Neural Adaptation

Science.gov (United States)

Li, Luozheng; Mi, Yuanyuan; Zhang, Wenhao; Wang, Da-Hui; Wu, Si

2018-01-01

Adaptation refers to the general phenomenon that the neural system dynamically adjusts its response property according to the statistics of external inputs. In response to an invariant stimulation, neuronal firing rates first increase dramatically and then decrease gradually to a low level close to the background activity. This prompts a question: during the adaptation, how does the neural system encode the repeated stimulation with attenuated firing rates? It has been suggested that the neural system may employ a dynamical encoding strategy during the adaptation, the information of stimulus is mainly encoded by the strong independent spiking of neurons at the early stage of the adaptation; while the weak but synchronized activity of neurons encodes the stimulus information at the later stage of the adaptation. The previous study demonstrated that short-term facilitation (STF) of electrical synapses, which increases the synchronization between neurons, can provide a mechanism to realize dynamical encoding. In the present study, we further explore whether short-term plasticity (STP) of chemical synapses, an interaction form more common than electrical synapse in the cortex, can support dynamical encoding. We build a large-size network with chemical synapses between neurons. Notably, facilitation of chemical synapses only enhances pair-wise correlations between neurons mildly, but its effect on increasing synchronization of the network can be significant, and hence it can serve as a mechanism to convey the stimulus information. To read-out the stimulus information, we consider that a downstream neuron receives balanced excitatory and inhibitory inputs from the network, so that the downstream neuron only responds to synchronized firings of the network. Therefore, the response of the downstream neuron indicates the presence of the repeated stimulation. Overall, our study demonstrates that STP of chemical synapse can serve as a mechanism to realize dynamical neural

Quasi-gas dynamic equations

CERN Document Server

Elizarova, Tatiana G

2009-01-01

This book presents two interconnected mathematical models generalizing the Navier-Stokes system. The models, called the quasi-gas-dynamic and quasi-hydrodynamic equations, are then used as the basis of numerical methods solving gas- and fluid-dynamic problems.

More dynamical supersymmetry breaking

International Nuclear Information System (INIS)

Csaki, C.; Randall, L.; Skiba, W.

1996-01-01

In this paper we introduce a new class of theories which dynamically break supersymmetry based on the gauge group SU(n) x SU(3) x U(1) for even n. These theories are interesting in that no dynamical superpotential is generated in the absence of perturbations. For the example SU(4) x SU(3) x U(1) we explicitly demonstrate that all flat directions can be lifted through a renormalizable superpotential and that supersymmetry is dynamically broken. We derive the exact superpotential for this theory, which exhibits new and interesting dynamical phenomena. For example, modifications to classical constraints can be field dependent. We also consider the generalization to SU(n) x SU(3) x U(1) models (with even n>4). We present a renormalizable superpotential which lifts all flat directions. Because SU(3) is not confining in the absence of perturbations, the analysis of supersymmetry breaking is very different in these theories from the n=4 example. When the SU(n) gauge group confines, the Yukawa couplings drive the SU(3) theory into a regime with a dynamically generated superpotential. By considering a simplified version of these theories we argue that supersymmetry is probably broken. (orig.)

Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR

International Nuclear Information System (INIS)

Mock, Raymond Cecil; Nash, Thomas J.; Sanford, Thomas W. L.

2007-01-01

We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-ray diagnostics fielded on Z are presented. These diagnostics include x-ray diodes, bolometers, fast x-ray imaging cameras, and crystal spectrometers. Analysis of these data indicates that the peak dynamic radiation temperature on Z is between 250 and 300 eV from a diameter less than 1 mm. Radiation from the dynamic hohlraum itself or from a radiatively driven pellet within the dynamic hohlraum has been used to probe a variety of matter associated with the dynamic hohlraum: the tungsten z-pinch itself, tungsten sliding across the end-on apertures, a titanium foil over the end aperture, and a silicon aerogel end cap. Data showing the existence of asymmetry in radiation emanating from the two ends of the dynamic hohlraum is presented, along with data showing load configurations that mitigate this asymmetry. 1D simulations of the dynamic hohlraum implosion are presented and compared to experimental data. The simulations provide insight into the dynamic hohlraum behavior but are not necessarily a reliable design tool because of the inherently 3D behavior of the imploding nested tungsten wire arrays

Advances in soil dynamics

DEFF Research Database (Denmark)

Advances in Soil Dynamics, Volume 3, represents the culmination of the work undertaken by the Advances in Soil Dynamics Monograph Committee, PM-45-01, about 15 years ago to summarize important developments in this field over the last 35 years. When this project was initiated, the main goal...... was to abridge major strides made in the general area of soil dynamics during the sixties, seventies, and eighties. However, by about the mid-nineties soil dynamics research in the US and much of the developed world had come to a virtual standstill. Although significant progress was made prior to the mid......-nineties, we still do not have a sound fundamental knowledge of soil-machine and soil-plant interactions. It is the hope of the editors that these three volumes will provide a ready reference for much needed future research in this area....

Coarse-graining complex dynamics

DEFF Research Database (Denmark)

Sibani, Paolo

2013-01-01

Continuous Time Random Walks (CTRW) are widely used to coarse-grain the evolution of systems jumping from a metastable sub-set of their configuration space, or trap, to another via rare intermittent events. The multi-scaled behavior typical of complex dynamics is provided by a fat...... macroscopic variables all produce identical long time relaxation behaviors. Hence, CTRW shed no light on the link between microscopic and macroscopic dynamics. We then highlight how a more recent approach, Record Dynamics (RD) provides a viable alternative, based on a very different set of physical ideas......: while CTRW make use of a renewal process involving identical traps of infinite size, RD embodies a dynamical entrenchment into a hierarchy of traps which are finite in size and possess different degrees of meta-stability. We show in particular how RD produces the stretched exponential, power...

Dynamical quantum teleportation

Energy Technology Data Exchange (ETDEWEB)

Muschik, Christine [ICFO-Institut de Ciencies Fotoniques (Spain); Polzik, Eugene [Niels Bohr Institute (Denmark); Cirac, Ignacio [Max-Planck-Institute (Germany)

2013-07-01

We introduce two protocols for inducing non-local dynamics between two separate parties. The first scheme allows for the engineering of an interaction between the two remote systems, while the second protocol induces a dynamics in one of the parties, which is controlled by the other one. Both schemes apply to continuous variable systems, run continuously in time and are based on instantaneous feedback.

Photochemical reaction dynamics

Energy Technology Data Exchange (ETDEWEB)

Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

1993-12-01

The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

Stability of dynamical systems

CERN Document Server

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

Advances in Dynamic Games

CERN Document Server

Breton, Michele

2011-01-01

This book focuses on various aspects of dynamic game theory, presenting state-of-the-art research and serving as a testament to the vitality and growth of the field of dynamic games and their applications. The selected contributions, written by experts in their respective disciplines, are outgrowths of presentations originally given at the 13th International Symposium of Dynamic Games and Applications held in WrocACaw. The book covers a variety of topics, ranging from theoretical developments in game theory and algorithmic methods to applications, examples, and analysis in fields as varied as

High enthalpy gas dynamics

CERN Document Server

Rathakrishnan, Ethirajan

2014-01-01

This is an introductory level textbook which explains the elements of high temperature and high-speed gas dynamics. written in a clear and easy to follow style, the author covers all the latest developments in the field including basic thermodynamic principles, compressible flow regimes and waves propagation in one volume covers theoretical modeling of High Enthalpy Flows, with particular focus on problems in internal and external gas-dynamic flows, of interest in the fields of rockets propulsion and hypersonic aerodynamics High enthalpy gas dynamics is a compulsory course for aerospace engine

Lectures on chaotic dynamical systems

CERN Document Server

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 Topography Revisited

Science.gov (United States)

Moresi, Louis

2015-04-01

Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

Dynamical systems

CERN Document Server

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

Dynamic optimization and differential games

CERN Document Server

Friesz, Terry L

2010-01-01

Dynamic Optimization and Differential Games has been written to address the increasing number of Operations Research and Management Science problems that involve the explicit consideration of time and of gaming among multiple agents. With end-of-chapter exercises throughout, it is a book that can be used both as a reference and as a textbook. It will be useful as a guide to engineers, operations researchers, applied mathematicians and social scientists whose work involves both the theoretical and computational aspects of dynamic optimization and differential games. Included throughout the text are detailed explanations of several original dynamic and game-theoretic mathematical models which are of particular relevance in today's technologically-driven-global economy: revenue management, oligopoly pricing, production planning, supply chain management, dynamic traffic assignment and dynamic congestion pricing. The book emphasizes deterministic theory, computational tools and applications associated with the stu...

Dynamical systems in population biology

CERN Document Server

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...

Analysis and control of complex dynamical systems robust bifurcation, dynamic attractors, and network complexity

CERN Document Server

Imura, Jun-ichi; Ueta, Tetsushi

2015-01-01

This book is the first to report on theoretical breakthroughs on control of complex dynamical systems developed by collaborative researchers in the two fields of dynamical systems theory and control theory. As well, its basic point of view is of three kinds of complexity: bifurcation phenomena subject to model uncertainty, complex behavior including periodic/quasi-periodic orbits as well as chaotic orbits, and network complexity emerging from dynamical interactions between subsystems. Analysis and Control of Complex Dynamical Systems offers a valuable resource for mathematicians, physicists, and biophysicists, as well as for researchers in nonlinear science and control engineering, allowing them to develop a better fundamental understanding of the analysis and control synthesis of such complex systems.

Introduction to dynamics

CERN Document Server

Pfeiffer, Friedrich

2015-01-01

This concise textbook for students preferably of a postgraduate level, but also for engineers in practice, contains the basic kinematical and kinetic structures of dynamics together with carefully selected applications. The book is a condensed introduction to the fundamental laws of kinematics and kinetics, on the most important principles of mechanics and presents the equations of motion in the form of Lagrange and Newton-Euler. Selected problems of linear and nonlinear dynamics are treated, as well as problems of vibration formation. The presented selection of topics gives a useful basis for stepping into more advanced problems of dynamics. The contents of this book represent the result of a regularly revised course, which has been and still is given for masters students at the Technische Universität München. .

Vegetation dynamics and dynamic vegetation science

NARCIS (Netherlands)

Van der Maarel, E

1996-01-01

his contribution presents a review of the development of the study of vegetation dynamics since 1979, in the framework of a jubilee meeting on progress in the study of vegetation. However, an exhaustive review is both impossible and unnecessary. It is impossible within the few pages available

Hydration dynamics in water clusters via quantum molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Turi, László, E-mail: turi@chem.elte.hu [Department of Physical Chemistry, Eötvös Loránd University, Budapest 112, P. O. Box 32, H-1518 (Hungary)

2014-05-28

We have investigated the hydration dynamics in size selected water clusters with n = 66, 104, 200, 500, and 1000 water molecules using molecular dynamics simulations. To study the most fundamental aspects of relaxation phenomena in clusters, we choose one of the simplest, still realistic, quantum mechanically treated test solute, an excess electron. The project focuses on the time evolution of the clusters following two processes, electron attachment to neutral equilibrated water clusters and electron detachment from an equilibrated water cluster anion. The relaxation dynamics is significantly different in the two processes, most notably restoring the equilibrium final state is less effective after electron attachment. Nevertheless, in both scenarios only minor cluster size dependence is observed. Significantly different relaxation patterns characterize electron detachment for interior and surface state clusters, interior state clusters relaxing significantly faster. This observation may indicate a potential way to distinguish surface state and interior state water cluster anion isomers experimentally. A comparison of equilibrium and non-equilibrium trajectories suggests that linear response theory breaks down for electron attachment at 200 K, but the results converge to reasonable agreement at higher temperatures. Relaxation following electron detachment clearly belongs to the linear regime. Cluster relaxation was also investigated using two different computational models, one preferring cavity type interior states for the excess electron in bulk water, while the other simulating non-cavity structure. While the cavity model predicts appearance of several different hydrated electron isomers in agreement with experiment, the non-cavity model locates only cluster anions with interior excess electron distribution. The present simulations show that surface isomers computed with the cavity predicting potential show similar dynamical behavior to the interior clusters of

Defect dynamics and coarsening dynamics in smectic-C films

Science.gov (United States)

Pargellis, A. N.; Finn, P.; Goodby, J. W.; Panizza, P.; Yurke, B.; Cladis, P. E.

1992-12-01

We study the dynamics of defects generated in free-standing films of liquid crystals following a thermal quench from the smectic-A phase to the smectic-C phase. The defects are type-1 disclinations, and the strain field between defect pairs is confined to 2π walls. We compare our observations with a phenomenological model that includes dipole coupling of the director field to an external ordering field. This model is able to account for both the observed coalescence dynamics and the observed ordering dynamics. In the absence of an ordering field, our model predicts the defect density ρ to scale with time t as ρ lnρ~t-1. When the dipole coupling of the director field to an external ordering field is included, both the model and experiments show the defect coarsening proceeds as ρ~e-αt with the strain field confined to 2π walls. The external ordering field most likely arises from the director's tendency to align with edge dislocations within the liquid-crystal film.

Dynamical systems examples of complex behaviour

CERN Document Server

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...

On the representation of contextual probabilistic dynamics in the complex Hilbert space: Linear and nonlinear evolutions, Schrodinger dynamics

International Nuclear Information System (INIS)

Khrennikov, A.

2005-01-01

We constructed the representation of contextual probabilistic dynamics in the complex Hilbert space. Thus dynamics of the wave function can be considered as Hilbert space projection of realistic dynamics in a pre space. The basic condition for representing the pre space-dynamics is the law of statistical conservation of energy-conservation of probabilities. The construction of the dynamical representation is an important step in the development of contextual statistical viewpoint of quantum processes. But the contextual statistical model is essentially more general than the quantum one. Therefore in general the Hilbert space projection of the pre space dynamics can be nonlinear and even irreversible (but it is always unitary). There were found conditions of linearity and reversibility of the Hilbert space dynamical projection. We also found conditions for the conventional Schrodinger dynamics (including time-dependent Hamiltonians). We remark that in general even the Schrodinger dynamics is based just on the statistical conservation of energy; for individual systems the law of conservation of energy can be violated (at least in our theoretical model)

[Approximation to the dynamics of meningococcal meningitis through dynamic systems and time series].

Science.gov (United States)

Canals, M

1996-02-01

Meningococcal meningitis is subjected to epidemiological surveillance due to its severity and the occasional presentation of epidemic outbreaks. This work analyses previous disease models, generate new ones and analyses monthly cases using ARIMA time series models. The results show that disease dynamics for closed populations is epidemic and the epidemic size is related to the proportion of carriers and the transmissiveness of the agent. In open populations, disease dynamics depends on the admission rate of susceptible and the relative admission of infected individuals. Our model considers a logistic populational growth and carrier admission proportional to populational size, generating an endemic dynamics. Considering a non-instantaneous system response, a greater realism is obtained establishing that the endemic situation may present a dynamics highly sensitive to initial conditions, depending on the transmissiveness and proportion of susceptible individuals in the population. Time series model showed an adequate predictive capacity in terms no longer than 10 months. The lack of long term predictability was attributed to local changes in the proportion of carriers or on transmissiveness that lead to chaotic dynamics over a seasonal pattern. Predictions for 1995 and 1996 were obtained.

The Mathlet Toolkit: Creating Dynamic Applets for Differential Equations and Dynamical Systems

Science.gov (United States)

Decker, Robert

2011-01-01

Dynamic/interactive graphing applets can be used to supplement standard computer algebra systems such as Maple, Mathematica, Derive, or TI calculators, in courses such as Calculus, Differential Equations, and Dynamical Systems. The addition of this type of software can lead to discovery learning, with students developing their own conjectures, and…

Integrating atomistic molecular dynamics simulations, experiments, and network analysis to study protein dynamics

DEFF Research Database (Denmark)

Papaleo, Elena

2015-01-01

that we observe and the functional properties of these important cellular machines. To make progresses in this direction, we need to improve the physical models used to describe proteins and solvent in molecular dynamics, as well as to strengthen the integration of experiments and simulations to overcome...... with the possibility to validate simulation methods and physical models against a broad range of experimental observables. On the other side, it also allows a complementary and comprehensive view on protein structure and dynamics. What is needed now is a better understanding of the link between the dynamic properties...... simulations with attention to the effects that can be propagated over long distances and are often associated to important biological functions. In this context, approaches inspired by network analysis can make an important contribution to the analysis of molecular dynamics simulations....

Dynamic gamma knife radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Luan Shuang; Swanson, Nathan; Chen Zhe [Department of Computer Science, University of New Mexico, Albuquerque, NM 87131 (United States); Ma Lijun [Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94143 (United States)], E-mail: sluan@cs.unm.edu, E-mail: nate@cs.unm.edu, E-mail: zchen@cs.unm.edu, E-mail: lijunma@radonc.ucsf.edu

2009-03-21

Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C(TM) and Perfexion(TM) units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can

Dynamic Capabilities and Performance

DEFF Research Database (Denmark)

Wilden, Ralf; Gudergan, Siegfried P.; Nielsen, Bo Bernhard

2013-01-01

are contingent on the competitive intensity faced by firms. Our findings demonstrate the performance effects of internal alignment between organizational structure and dynamic capabilities, as well as the external fit of dynamic capabilities with competitive intensity. We outline the advantages of PLS...

Dynamics on the Circle

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 11. Dynamics on the Circle - Interval Dynamics and Rotation Number. Siddhartha Gadgil. General Article Volume 8 Issue 11 November 2003 pp 25-36. Fulltext. Click here to view fulltext PDF. Permanent link:

Dynamic behaviour of prestressed concrete bridges

International Nuclear Information System (INIS)

Javor, T.

1982-01-01

The paper presents the results of experimental research of dynamic effects on prestressed concrete bridges in dynamic load tests using testing vehicles. The bridges were passed over in both directions at various speeds also running over an artificial unevenness to produce impact loads. From investigated bridges are shown the dynamic quantities such as dynamic coefficients, natural frequency, logarithmical decrement of damping, etc. (orig.) [de

Supervision and group dynamics

DEFF Research Database (Denmark)

Hansen, Søren; Jensen, Lars Peter

2004-01-01

 An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience...... that many students are having difficulties with practical issues such as collaboration, communication, and project management. Most supervisors either ignore this demand, because they do not find it important or they find it frustrating, because they do not know, how to supervise group dynamics...... as well as at Aalborg University. The first visible result has been participating supervisors telling us that the course has inspired them to try supervising group dynamics in the future. This paper will explore some aspects of supervising group dynamics as well as, how to develop the Aalborg model...

Stochastic dynamics and irreversibility

CERN Document Server

Tomé, Tânia

2015-01-01

This textbook presents an exposition of stochastic dynamics and irreversibility. It comprises the principles of probability theory and the stochastic dynamics in continuous spaces, described by Langevin and Fokker-Planck equations, and in discrete spaces, described by Markov chains and master equations. Special concern is given to the study of irreversibility, both in systems that evolve to equilibrium and in nonequilibrium stationary states. Attention is also given to the study of models displaying phase transitions and critical phenomema both in thermodynamic equilibrium and out of equilibrium. These models include the linear Glauber model, the Glauber-Ising model, lattice models with absorbing states such as the contact process and those used in population dynamic and spreading of epidemic, probabilistic cellular automata, reaction-diffusion processes, random sequential adsorption and dynamic percolation. A stochastic approach to chemical reaction is also presented.The textbook is intended for students of ...

Conceptualizing Teacher Identity as a Complex Dynamic System: The Inner Dynamics of Transformations during a Practicum

Science.gov (United States)

Henry, Alastair

2016-01-01

Currently, the inner dynamics of teacher identity transformations remain a "black box." Conceptualizing preservice teacher identity as a complex dynamic system, and the notion of "being someone who teaches" in dialogical terms as involving shifts between different teacher voices, the study investigates the dynamical processes…

Nonlinear dynamics in biological systems

CERN Document Server

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...

Dynamics of glass-forming liquids

DEFF Research Database (Denmark)

Hansen, Henriette Wase

on alpha relaxation dynamics, and for the two van der Waals liquids, also when we have separation of timescales, i.e. the alpha relaxation is not contributing to the picosecond dynamics. The concept of isomorphs is observed to break down in two cases for the hydrogen bonding system: in density scaling......The overall theme of this work has been to experimentally test the shoving model and isomorph theory related to the dynamics of glass-forming liquids, both of which, rather than being universal explanations, are expected to work in the simplest case. We test the connection between fast and slow...... dynamics in light of the shoving model from the temperature dependence of the mean-squared displacement from neutron scattering at nanosecond timescale and the elastic modulus from shear mechanics. We find the fast dynamics to correlate with the alpha relaxation time and fragility in agreement...

Financial fragility and global dynamics

International Nuclear Information System (INIS)

Dieci, Roberto; Sordi, Serena; Vercelli, Alessandro

2006-01-01

This paper deals with a simple model of financial fluctuations, where a crucial role is played by the dynamic interaction between aggregate current and intertemporal financial ratios. The model results in a 4D discrete-time dynamical system-capable of generating complex dynamics-which is analyzed by means of both analytical tools, such as local stability analysis and bifurcation theory, and numerical simulations. The behavior of the model is studied for different parameter regimes. We show that its dynamic behavior is very sensitive to the parameters that represent (1) the speed of adjustment of the desired current financial ratio towards a safe level of the intertemporal one and (2) the intensity with which aggregate current financial decisions affect future financial constraints. In particular, different parameter regimes are identified, giving rise to two different 'routes' to complexity, one leading to chaotic dynamics, the other to a coexistence of attractors and path-dependence

Ergodic theory and dynamical systems

CERN Document Server

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...

Analytical methods in rotor dynamics

CERN Document Server

Dimarogonas, Andrew D; Chondros, Thomas G

2013-01-01

The design and construction of rotating machinery operating at supercritical speeds was, in the 1920s, an event of revolutionary importance for the then new branch of dynamics known as rotor dynamics. In the 1960s, another revolution occurred: In less than a decade, imposed by operational and economic needs, an increase in the power of turbomachinery by one order of magnitude took place. Dynamic analysis of complex rotor forms became a necessity, while the importance of approximate methods for dynamic analysis was stressed. Finally, the emergence of fracture mechanics, as a new branch of applied mechanics, provided analytical tools to investigate crack influence on the dynamic behavior of rotors. The scope of this book is based on all these developments. No topics related to the well-known classical problems are included, rather the book deals exclusively with modern high-power turbomachinery.

Static Analysis of Dynamic Languages

DEFF Research Database (Denmark)

Madsen, Magnus

Dynamic programming languages are highly popular and widely used. Java- Script is often called the lingua franca of the web and it is the de facto standard for client-side web programming. On the server-side the PHP, Python and Ruby languages are prevalent. What these languages have in common...... with static type systems, such as Java and C# , but the same features are rarely available for dynamic languages such as JavaScript. The aim of this thesis is to investigate techniques for improving the tool- support for dynamic programming languages without imposing any artificial restrictions...... of new dataflow analysis techniques to tackle the nature of dynamic programming languages....

Shadowing in dynamical systems

CERN Document Server

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.

Unpacking dynamic capability : a design perspective

NARCIS (Netherlands)

Mulders, D.E.M.; Romme, A.G.L.; Bøllingtoft, A.; Håkonsson, D.D.; Nielsen, J.F.; Snow, C.C; Ulhøi, J.

2009-01-01

This chapter reviews the dynamic capability literature to explore relationships between definition, operationalization, and measurement of dynamic capability. Subsequently, we develop a design-oriented approach toward dynamic capability that distinguishes between design rules, recurrent patterns of

Dynamics on Networks of Manifolds

Science.gov (United States)

DeVille, Lee; Lerman, Eugene

2015-03-01

We propose a precise definition of a continuous time dynamical system made up of interacting open subsystems. The interconnections of subsystems are coded by directed graphs. We prove that the appropriate maps of graphs called graph fibrations give rise to maps of dynamical systems. Consequently surjective graph fibrations give rise to invariant subsystems and injective graph fibrations give rise to projections of dynamical systems.

Dynamic paradigm of turbulence

International Nuclear Information System (INIS)

Mukhamedov, Alfred M.

2006-01-01

In this paper a dynamic paradigm of turbulence is proposed. The basic idea consists in the novel definition of chaotic structure given with the help of Pfaff system of PDE associated with the turbulent dynamics. A methodological analysis of the new and the former paradigm is produced

Multiple quantum spin dynamics of entanglement

International Nuclear Information System (INIS)

Doronin, Serge I.

2003-01-01

The dynamics of entanglement is investigated on the basis of exactly solvable models of multiple quantum (MQ) NMR spin dynamics. It is shown that the time evolution of MQ coherences of systems of coupled nuclear spins in solids is directly connected with dynamics of the quantum entanglement. We studied analytically the dynamics of entangled states for two- and three-spin systems coupled by the dipole-dipole interaction. In this case the dynamics of the quantum entanglement is uniquely determined by the time evolution of MQ coherences of the second order. The real part of the density matrix describing MQ dynamics in solids is responsible for MQ coherences of the zeroth order while its imaginary part is responsible for the second order. Thus, one can conclude that the dynamics of the entanglement is connected with transitions from the real part of the density matrix to the imaginary one, and vice versa. A pure state which generalizes the Greenberger-Horne-Zeilinger (GHZ) and W states is found. Different measures of the entanglement of this state are analyzed for tripartite systems

Symbolic dynamics and description of complexity

International Nuclear Information System (INIS)

Hao Bailin.

1992-10-01

Symbolic dynamics provides a general framework to describe complexity of dynamical behaviour. After a discussion of the state of the filed special emphasis will be made on the role of transfer matrix (the Stefan matrix) both in deriving the grammar from known symbolic dynamics and in extracting the rules from experimental data. The block structure of the Stefan matrix may serve as another indicator of complexity of the associated dynamics. (author). 33 refs, 6 figs

ONR Ocean Wave Dynamics Workshop

Science.gov (United States)

In anticipation of the start (in Fiscal Year 1988) of a new Office of Naval Research (ONR) Accelerated Research Initiative (ARI) on Ocean Surface Wave Dynamics, a workshop was held August 5-7, 1986, at Woods Hole, Mass., to discuss new ideas and directions of research. This new ARI on Ocean Surface Wave Dynamics is a 5-year effort that is organized by the ONR Physical Oceanography Program in cooperation with the ONR Fluid Mechanics Program and the Physical Oceanography Branch at the Naval Ocean Research and Development Activity (NORDA). The central theme is improvement of our understanding of the basic physics and dynamics of surface wave phenomena, with emphasis on the following areas: precise air-sea coupling mechanisms,dynamics of nonlinear wave-wave interaction under realistic environmental conditions,wave breaking and dissipation of energy,interaction between surface waves and upper ocean boundary layer dynamics, andsurface statistical and boundary layer coherent structures.

Speckle dynamics under ergodicity breaking

Science.gov (United States)

Sdobnov, Anton; Bykov, Alexander; Molodij, Guillaume; Kalchenko, Vyacheslav; Jarvinen, Topias; Popov, Alexey; Kordas, Krisztian; Meglinski, Igor

2018-04-01

Laser speckle contrast imaging (LSCI) is a well-known and versatile approach for the non-invasive visualization of flows and microcirculation localized in turbid scattering media, including biological tissues. In most conventional implementations of LSCI the ergodic regime is typically assumed valid. However, most composite turbid scattering media, especially biological tissues, are non-ergodic, containing a mixture of dynamic and static centers of light scattering. In the current study, we examined the speckle contrast in different dynamic conditions with the aim of assessing limitations in the quantitative interpretation of speckle contrast images. Based on a simple phenomenological approach, we introduced a coefficient of speckle dynamics to quantitatively assess the ratio of the dynamic part of a scattering medium to the static one. The introduced coefficient allows one to distinguish real changes in motion from the mere appearance of static components in the field of view. As examples of systems with static/dynamic transitions, thawing and heating of Intralipid samples were studied by the LSCI approach.

Classical dynamics a modern perspective

CERN Document Server

Sudarshan, Ennackal Chandy George

2016-01-01

Classical dynamics is traditionally treated as an early stage in the development of physics, a stage that has long been superseded by more ambitious theories. Here, in this book, classical dynamics is treated as a subject on its own as well as a research frontier. Incorporating insights gained over the past several decades, the essential principles of classical dynamics are presented, while demonstrating that a number of key results originally considered only in the context of quantum theory and particle physics, have their foundations in classical dynamics.Graduate students in physics and practicing physicists will welcome the present approach to classical dynamics that encompasses systems of particles, free and interacting fields, and coupled systems. Lie groups and Lie algebras are incorporated at a basic level and are used in describing space-time symmetry groups. There is an extensive discussion on constrained systems, Dirac brackets and their geometrical interpretation. The Lie-algebraic description of ...

Dynamics Laboratory

Data.gov (United States)

Federal Laboratory Consortium — The Dynamics Lab replicates vibration environments for every Navy platform. Testing performed includes: Flight Clearance, Component Improvement, Qualification, Life...

Hydration dynamics near a model protein surface

International Nuclear Information System (INIS)

Russo, Daniela; Hura, Greg; Head-Gordon, Teresa

2003-01-01

The evolution of water dynamics from dilute to very high concentration solutions of a prototypical hydrophobic amino acid with its polar backbone, N-acetyl-leucine-methylamide (NALMA), is studied by quasi-elastic neutron scattering and molecular dynamics simulation for both the completely deuterated and completely hydrogenated leucine monomer. We observe several unexpected features in the dynamics of these biological solutions under ambient conditions. The NALMA dynamics shows evidence of de Gennes narrowing, an indication of coherent long timescale structural relaxation dynamics. The translational water dynamics are analyzed in a first approximation with a jump diffusion model. At the highest solute concentrations, the hydration water dynamics is significantly suppressed and characterized by a long residential time and a slow diffusion coefficient. The analysis of the more dilute concentration solutions takes into account the results of the 2.0M solution as a model of the first hydration shell. Subtracting the first hydration layer based on the 2.0M spectra, the translational diffusion dynamics is still suppressed, although the rotational relaxation time and residential time are converged to bulk-water values. Molecular dynamics analysis shows spatially heterogeneous dynamics at high concentration that becomes homogeneous at more dilute concentrations. We discuss the hydration dynamics results of this model protein system in the context of glassy systems, protein function, and protein-protein interfaces

Integrating atomistic molecular dynamics simulations, experiments and network analysis to study protein dynamics: strength in unity

Directory of Open Access Journals (Sweden)

Elena ePapaleo

2015-05-01

Full Text Available In the last years, we have been observing remarkable improvements in the field of protein dynamics. Indeed, we can now study protein dynamics in atomistic details over several timescales with a rich portfolio of experimental and computational techniques. On one side, this provides us with the possibility to validate simulation methods and physical models against a broad range of experimental observables. On the other side, it also allows a complementary and comprehensive view on protein structure and dynamics. What is needed now is a better understanding of the link between the dynamic properties that we observe and the functional properties of these important cellular machines. To make progresses in this direction, we need to improve the physical models used to describe proteins and solvent in molecular dynamics, as well as to strengthen the integration of experiments and simulations to overcome their own limitations. Moreover, now that we have the means to study protein dynamics in great details, we need new tools to understand the information embedded in the protein ensembles and in their dynamic signature. With this aim in mind, we should enrich the current tools for analysis of biomolecular simulations with attention to the effects that can be propagated over long distances and are often associated to important biological functions. In this context, approaches inspired by network analysis can make an important contribution to the analysis of molecular dynamics simulations.

Dynamic stiffness of suction caissons - vertical vibrations

Energy Technology Data Exchange (ETDEWEB)

Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

2006-12-15

The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

Photocatalytic oxidation dynamics of acetone on TiO2: tight-binding quantum chemical molecular dynamics study

International Nuclear Information System (INIS)

Lv Chen; Wang Xiaojing; Agalya, Govindasamy; Koyama, Michihisa; Kubo, Momoji; Miyamoto, Akira

2005-01-01

The clarification of the excited states dynamics on TiO 2 surface is important subject for the design of the highly active photocatalysts. In the present study, we applied our novel tight-binding quantum chemical molecular dynamics method to the investigation on the photocatalytic oxidation dynamics of acetone by photogenerated OH radicals on the hydrated anatase TiO 2 surface. The elucidated photocatalytic reaction mechanism strongly supports the previous experimental proposal and finally the effectiveness of our new approach for the clarification of the photocatalytic reaction dynamics employing the large simulation model was confirmed

Discrete event dynamic system (DES)-based modeling for dynamic material flow in the pyroprocess

International Nuclear Information System (INIS)

Lee, Hyo Jik; Kim, Kiho; Kim, Ho Dong; Lee, Han Soo

2011-01-01

A modeling and simulation methodology was proposed in order to implement the dynamic material flow of the pyroprocess. Since the static mass balance provides the limited information on the material flow, it is hard to predict dynamic behavior according to event. Therefore, a discrete event system (DES)-based model named, PyroFlow, was developed at the Korea Atomic Energy Research Institute (KAERI). PyroFlow is able to calculate dynamic mass balance and also show various dynamic operational results in real time. By using PyroFlow, it is easy to rapidly predict unforeseeable results, such as throughput in unit process, accumulated product in buffer and operation status. As preliminary simulations, bottleneck analyses in the pyroprocess were carried out and consequently it was presented that operation strategy had influence on the productivity of the pyroprocess.

Distinctive Dynamic Capabilities for New Business Creation

DEFF Research Database (Denmark)

Rosenø, Axel; Enkel, Ellen; Mezger, Florian

2013-01-01

This study examines the distinctive dynamic capabilities for new business creation in established companies. We argue that these are very different from those for managing incremental innovation within a company's core business. We also propose that such capabilities are needed in both slow...... and fast-paced industries, and that similarities exist across industries. Hence, the study contributes to dynamic capabilities literature by: 1) identifying the distinctive dynamic capabilities for new business creation; 2) shifting focus away from dynamic capabilities in environments characterised by high...... clock-speed and uncertainty towards considering dynamic capabilities for the purpose of developing new businesses, which also implies a high degree of uncertainty. Based on interviews with 33 companies, we identify distinctive dynamic capabilities for new business creation, find that dynamic...

Fluid dynamics of moving fish in a two-dimensional multiparticle collision dynamics model

NARCIS (Netherlands)

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

General relativistic chaos and nonlinear dynamics

Energy Technology Data Exchange (ETDEWEB)

Barrow, J D [California Univ., Berkeley (USA). Dept. of Physics

1982-06-01

How new ideas in dynamical systems theory find application in the description of general relativistic systems is described. The concept of dynamical entropy is explained and the associated invariant evaluated for the Mixmaster cosmological model. The description of cosmological models as measure preserving dynamical systems leads to a number of interconnections with new ideas in non-linear dynamics. This may provide a new avenue of approach to ascertaining the nature of the general solution to Einstein's equations.

General relativistic chaos and nonlinear dynamics

International Nuclear Information System (INIS)

Barrow, J.D.

1982-01-01

How new ideas in dynamical systems theory find application in the description of general relativistic systems is described. The concept of dynamical entropy is explained and the associated invariant evaluated for the Mixmaster cosmological model. The description of cosmological models as measure preserving dynamical systems leads to a number of interconnections with new ideas in non-linear dynamics. This may provide a new avenue of approach to ascertaining the nature of the general solution to Einstein's equations. (author)

NMR investigations of molecular dynamics

Science.gov (United States)

Palmer, Arthur

2011-03-01

NMR spectroscopy is a powerful experimental approach for characterizing protein conformational dynamics on multiple time scales. The insights obtained from NMR studies are complemented and by molecular dynamics (MD) simulations, which provide full atomistic details of protein dynamics. Homologous mesophilic (E. coli) and thermophilic (T. thermophilus) ribonuclease H (RNase H) enzymes serve to illustrate how changes in protein sequence and structure that affect conformational dynamic processes can be monitored and characterized by joint analysis of NMR spectroscopy and MD simulations. A Gly residue inserted within a putative hinge between helices B and C is conserved among thermophilic RNases H, but absent in mesophilic RNases H. Experimental spin relaxation measurements show that the dynamic properties of T. thermophilus RNase H are recapitulated in E. coli RNase H by insertion of a Gly residue between helices B and C. Additional specific intramolecular interactions that modulate backbone and sidechain dynamical properties of the Gly-rich loop and of the conserved Trp residue flanking the Gly insertion site have been identified using MD simulations and subsequently confirmed by NMR spin relaxation measurements. These results emphasize the importance of hydrogen bonds and local steric interactions in restricting conformational fluctuations, and the absence of such interactions in allowing conformational adaptation to substrate binding.

Social opinion dynamics is not chaotic

Science.gov (United States)

Lim, Chjan; Zhang, Weituo

2016-08-01

Motivated by the research on social opinion dynamics over large and dense networks, a general framework for verifying the monotonicity property of multi-agent dynamics is introduced. This allows a derivation of sociologically meaningful sufficient conditions for monotonicity that are tailor-made for social opinion dynamics, which typically have high nonlinearity. A direct consequence of monotonicity is that social opinion dynamics is nonchaotic. A key part of this framework is the definition of a partial order relation that is suitable for a large class of social opinion dynamics such as the generalized naming games. Comparisons are made to previous techniques to verify monotonicity. Using the results obtained, we extend many of the consequences of monotonicity to this class of social dynamics, including several corollaries on their asymptotic behavior, such as global convergence to consensus and tipping points of a minority fraction of zealots or leaders.

The onset of dynamic stall revisited

Energy Technology Data Exchange (ETDEWEB)

Mulleners, Karen; Raffel, Markus [German Aerospace Center (DLR), Goettingen (Germany)

2012-03-15

Dynamic stall on a helicopter rotor blade comprises a series of complex aerodynamic phenomena in response to the unsteady change of the blade's angle of attack. It is accompanied by a lift overshoot and delayed massive flow separation with respect to static stall. The classical hallmark of the dynamic stall phenomenon is the dynamic stall vortex. The flow over an oscillating OA209 airfoil under dynamic stall conditions was investigated by means of unsteady surface pressure measurements and time-resolved particle image velocimetry. The characteristic features of the unsteady flow field were identified and analysed utilising different coherent structure identification methods. An Eulerian and a Lagrangian procedure were adopted to locate the axes of vortices and the edges of Lagrangian coherent structures, respectively; a proper orthogonal decomposition of the velocity field revealed the energetically dominant coherent flow patterns and their temporal evolution. Based on the complementary information obtained by these methods the dynamics and interaction of vortical structures were analysed within a single dynamic stall life cycle leading to a classification of the unsteady flow development into five successive stages: the attached flow stage; the stall development stage; stall onset; the stalled stage; and flow reattachment. The onset of dynamic stall was specified here based on a characteristic mode of the proper orthogonal decomposition of the velocity field. Variations in the flow field topology that accompany the stall onset were verified by the Lagrangian coherent structure analysis. The instantaneous effective unsteadiness was defined as a single representative parameter to describe the influence of the motion parameters. Dynamic stall onset was found to be promoted by increasing unsteadiness. The mechanism that results in the detachment of the dynamic stall vortex from the airfoil was identified as vortex-induced separation caused by strong viscous

Dynamic Power Management for Portable Hybrid Power-Supply Systems Utilizing Approximate Dynamic Programming

Directory of Open Access Journals (Sweden)

Jooyoung Park

2015-05-01

Full Text Available Recently, the optimization of power flows in portable hybrid power-supply systems (HPSSs has become an important issue with the advent of a variety of mobile systems and hybrid energy technologies. In this paper, a control strategy is considered for dynamically managing power flows in portable HPSSs employing batteries and supercapacitors. Our dynamic power management strategy utilizes the concept of approximate dynamic programming (ADP. ADP methods are important tools in the fields of stochastic control and machine learning, and the utilization of these tools for practical engineering problems is now an active and promising research field. We propose an ADP-based procedure based on optimization under constraints including the iterated Bellman inequalities, which can be solved by convex optimization carried out offline, to find the optimal power management rules for portable HPSSs. The effectiveness of the proposed procedure is tested through dynamic simulations for smartphone workload scenarios, and simulation results show that the proposed strategy can successfully cope with uncertain workload demands.

Dynamics at the nanoscale

International Nuclear Information System (INIS)

Stoneham, A.M.; Gavartin, J.L.

2007-01-01

However fascinating structures may be at the nanoscale, time-dependent behaviour at the nanoscale has far greater importance. Some of the dynamics is random, with fluctuations controlling rate processes and making thermal ratchets possible. Some of the dynamics causes the transfer of energy, of signals, or of charge. Such transfers are especially efficiently controlled in biological systems. Other dynamical processes occur when we wish to control the nanoscale, e.g., to avoid local failures of gate dielectrics, or to manipulate structures by electronic excitation, to use spin manipulation in quantum information processing. Our prime purpose is to make clear the enormous range and variety of time-dependent nanoscale phenomena

Fusion-fission dynamics

International Nuclear Information System (INIS)

Blocki, J.; Planeta, R.; Brzychczyk, J.; Grotowski, K.

1992-01-01

Classical dynamical calculations of the heavy ion induced fission processes have been performed for the reactions 40 Ar+ 141 Pr, 20 Ne+ 165 Ho and 12 C+ 175 Lu leading to the iridium like nucleus. As a result prescission lifetimes were obtained and compared with the experimental values. The comparison between the calculated and experimental lifetimes indicates that the one-body dissipation picture is much more relevant in describing the fusion-fission dynamics than the two-body one. (orig.)

International Conference on Dynamical Systems : Theory and Applications

CERN Document Server

2016-01-01

The book is a collection of contributions devoted to analytical, numerical and experimental techniques of dynamical systems, presented at the international conference "Dynamical Systems: Theory and Applications," held in Lódz, Poland on December 7-10, 2015. The studies give deep insight into new perspectives in analysis, simulation, and optimization of dynamical systems, emphasizing directions for future research. Broadly outlined topics covered include: bifurcation and chaos in dynamical systems, asymptotic methods in nonlinear dynamics, dynamics in life sciences and bioengineering, original numerical methods of vibration analysis, control in dynamical systems, stability of dynamical systems, vibrations of lumped and continuous sytems, non-smooth systems, engineering systems and differential equations, mathematical approaches to dynamical systems, and mechatronics.

International Conference on Dynamical Systems : Theory and Applications

CERN Document Server

2016-01-01

The book is the second volume of a collection of contributions devoted to analytical, numerical and experimental techniques of dynamical systems, presented at the international conference "Dynamical Systems: Theory and Applications," held in Lódz, Poland on December 7-10, 2015. The studies give deep insight into new perspectives in analysis, simulation, and optimization of dynamical systems, emphasizing directions for future research. Broadly outlined topics covered include: bifurcation and chaos in dynamical systems, asymptotic methods in nonlinear dynamics, dynamics in life sciences and bioengineering, original numerical methods of vibration analysis, control in dynamical systems, stability of dynamical systems, vibrations of lumped and continuous sytems, non-smooth systems, engineering systems and differential equations, mathematical approaches to dynamical systems, and mechatronics.

Dynamic photosynthesis in different environmental conditions.

Science.gov (United States)

Kaiser, Elias; Morales, Alejandro; Harbinson, Jeremy; Kromdijk, Johannes; Heuvelink, Ep; Marcelis, Leo F M

2015-05-01

Incident irradiance on plant leaves often fluctuates, causing dynamic photosynthesis. Whereas steady-state photosynthetic responses to environmental factors have been extensively studied, knowledge of dynamic modulation of photosynthesis remains scarce and scattered. This review addresses this discrepancy by summarizing available data and identifying the research questions necessary to advance our understanding of interactions between environmental factors and dynamic behaviour of photosynthesis using a mechanistic framework. Firstly, dynamic photosynthesis is separated into sub-processes related to proton and electron transport, non-photochemical quenching, control of metabolite flux through the Calvin cycle (activation states of Rubisco and RuBP regeneration, and post-illumination metabolite turnover), and control of CO₂ supply to Rubisco (stomatal and mesophyll conductance changes). Secondly, the modulation of dynamic photosynthesis and its sub-processes by environmental factors is described. Increases in ambient CO₂ concentration and temperature (up to ~35°C) enhance rates of photosynthetic induction and decrease its loss, facilitating more efficient dynamic photosynthesis. Depending on the sensitivity of stomatal conductance, dynamic photosynthesis may additionally be modulated by air humidity. Major knowledge gaps exist regarding environmental modulation of loss of photosynthetic induction, dynamic changes in mesophyll conductance, and the extent of limitations imposed by stomatal conductance for different species and environmental conditions. The study of mutants or genetic transformants for specific processes under various environmental conditions could provide significant progress in understanding the control of dynamic photosynthesis. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Coulomb interactions via local dynamics: a molecular-dynamics algorithm

International Nuclear Information System (INIS)

Pasichnyk, Igor; Duenweg, Burkhard

2004-01-01

We derive and describe in detail a recently proposed method for obtaining Coulomb interactions as the potential of mean force between charges which are dynamically coupled to a local electromagnetic field. We focus on the molecular dynamics version of the method and show that it is intimately related to the Car-Parrinello approach, while being equivalent to solving Maxwell's equations with a freely adjustable speed of light. Unphysical self-energies arise as a result of the lattice interpolation of charges, and are corrected by a subtraction scheme based on the exact lattice Green function. The method can be straightforwardly parallelized using standard domain decomposition. Some preliminary benchmark results are presented

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.

Dynamical calculation of nuclear temperature

International Nuclear Information System (INIS)

Zheng Yuming

1998-01-01

A new dynamical approach for measuring the temperature of a Hamiltonian dynamical system in the microcanonical ensemble of thermodynamics is presented. It shows that under the hypothesis of ergodicity the temperature can be computed as a time average of a function on the energy surface. This method not only yields an efficient computational approach for determining the temperature, but also provides an intrinsic link between dynamical system theory and the statistical mechanics of Hamiltonian system

Passivity and Evolutionary Game Dynamics

KAUST Repository

Park, Shinkyu; Shamma, Jeff S.; Martins, Nuno C.

2018-01-01

This paper investigates an energy conservation and dissipation -- passivity -- aspect of dynamic models in evolutionary game theory. We define a notion of passivity using the state-space representation of the models, and we devise systematic methods to examine passivity and to identify properties of passive dynamic models. Based on the methods, we describe how passivity is connected to stability in population games and illustrate stability of passive dynamic models using numerical simulations.

Passivity and Evolutionary Game Dynamics

KAUST Repository

Park, Shinkyu

2018-03-21

This paper investigates an energy conservation and dissipation -- passivity -- aspect of dynamic models in evolutionary game theory. We define a notion of passivity using the state-space representation of the models, and we devise systematic methods to examine passivity and to identify properties of passive dynamic models. Based on the methods, we describe how passivity is connected to stability in population games and illustrate stability of passive dynamic models using numerical simulations.

Assessment of deep dynamic mechanical sensitivity in individuals with tension-type headache: The dynamic pressure algometry.

Science.gov (United States)

Palacios-Ceña, M; Wang, K; Castaldo, M; Guerrero-Peral, Á; Caminero, A B; Fernández-de-Las-Peñas, C; Arendt-Nielsen, L

2017-09-01

To explore the validity of dynamic pressure algometry for evaluating deep dynamic mechanical sensitivity by assessing its association with headache features and widespread pressure sensitivity in tension-type headache (TTH). One hundred and eighty-eight subjects with TTH (70% women) participated. Deep dynamic sensitivity was assessed with a dynamic pressure algometry set (Aalborg University, Denmark © ) consisting of 11 different rollers including fixed levels from 500 g to 5300 g. Each roller was moved at a speed of 0.5 cm/s over a 60-mm horizontal line covering the temporalis muscle. Dynamic pain threshold (DPT-level of the first painful roller) was determined and pain intensity during DPT was rated on a numerical pain rate scale (NPRS, 0-10). Headache clinical features were collected on a headache diary. As gold standard, static pressure pain thresholds (PPT) were assessed over temporalis, C5/C6 joint, second metacarpal, and tibialis anterior muscle. Side-to-side consistency between DPT (r = 0.843, p  r > 0.656, all p headaches supporting that deep dynamic pressure sensitivity within the trigeminal area is consistent with widespread pressure sensitivity. Assessing deep static and dynamic somatic tissue pain sensitivity may provide new opportunities for differentiated diagnostics and possibly a new tool for assessing treatment effects. The current study found that dynamic pressure algometry in the temporalis muscle was associated with widespread pressure pain sensitivity in individuals with tension-type headache. The association was independent of the frequency of headaches. Assessing deep static and dynamic somatic tissue pain sensitivity may provide new opportunities for differentiated diagnostics and possibly a tool for assessing treatment effects. © 2017 European Pain Federation - EFIC®.

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 c...

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.

Structural stability of nonlinear population dynamics.

Science.gov (United States)

Cenci, Simone; Saavedra, Serguei

2018-01-01

In population dynamics, the concept of structural stability has been used to quantify the tolerance of a system to environmental perturbations. Yet, measuring the structural stability of nonlinear dynamical systems remains a challenging task. Focusing on the classic Lotka-Volterra dynamics, because of the linearity of the functional response, it has been possible to measure the conditions compatible with a structurally stable system. However, the functional response of biological communities is not always well approximated by deterministic linear functions. Thus, it is unclear the extent to which this linear approach can be generalized to other population dynamics models. Here, we show that the same approach used to investigate the classic Lotka-Volterra dynamics, which is called the structural approach, can be applied to a much larger class of nonlinear models. This class covers a large number of nonlinear functional responses that have been intensively investigated both theoretically and experimentally. We also investigate the applicability of the structural approach to stochastic dynamical systems and we provide a measure of structural stability for finite populations. Overall, we show that the structural approach can provide reliable and tractable information about the qualitative behavior of many nonlinear dynamical systems.

Hydrodynamic relaxations in dissipative particle dynamics

Science.gov (United States)

Hansen, J. S.; Greenfield, Michael L.; Dyre, Jeppe C.

2018-01-01

This paper studies the dynamics of relaxation phenomena in the standard dissipative particle dynamics (DPD) model [R. D. Groot and P. B. Warren, J. Chem. Phys. 107, 4423 (1997)]. Using fluctuating hydrodynamics as the framework of the investigation, we focus on the collective transverse and longitudinal dynamics. It is shown that classical hydrodynamic theory predicts the transverse dynamics at relatively low temperatures very well when compared to simulation data; however, the theory predictions are, on the same length scale, less accurate for higher temperatures. The agreement with hydrodynamics depends on the definition of the viscosity, and here we find that the transverse dynamics are independent of the dissipative and random shear force contributions to the stress. For high temperatures, the spectrum for the longitudinal dynamics is dominated by the Brillouin peak for large length scales and the relaxation is therefore governed by sound wave propagation and is athermal. This contrasts the results at lower temperatures and small length scale, where the thermal process is clearly present in the spectra. The DPD model, at least qualitatively, re-captures the underlying hydrodynamical mechanisms, and quantitative agreement is excellent at intermediate temperatures for the transverse dynamics.

Structural stability of nonlinear population dynamics

Science.gov (United States)

Cenci, Simone; Saavedra, Serguei

2018-01-01

In population dynamics, the concept of structural stability has been used to quantify the tolerance of a system to environmental perturbations. Yet, measuring the structural stability of nonlinear dynamical systems remains a challenging task. Focusing on the classic Lotka-Volterra dynamics, because of the linearity of the functional response, it has been possible to measure the conditions compatible with a structurally stable system. However, the functional response of biological communities is not always well approximated by deterministic linear functions. Thus, it is unclear the extent to which this linear approach can be generalized to other population dynamics models. Here, we show that the same approach used to investigate the classic Lotka-Volterra dynamics, which is called the structural approach, can be applied to a much larger class of nonlinear models. This class covers a large number of nonlinear functional responses that have been intensively investigated both theoretically and experimentally. We also investigate the applicability of the structural approach to stochastic dynamical systems and we provide a measure of structural stability for finite populations. Overall, we show that the structural approach can provide reliable and tractable information about the qualitative behavior of many nonlinear dynamical systems.

Microsoft Dynamics GP 2013 financial management

CERN Document Server

Grieve, Ian

2013-01-01

A standard tutorial-based approach covering Microsoft Dynamics GP 2013 and its six financial modules. The book is intended to allow users to improve their system use and workflow by introducing new modules to assist in financial management.This book is for you if you're a Dynamics GP partner, or Dynamics GP user, primarily focused on delivering application optimizations. This book assumes that you have a working knowledge of Microsoft Dynamics GP and have an understanding of the requirements of financial management.

Nonlinear dynamics aspects of particle accelerators. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Jowett, J M; Turner, S; Month, M

1986-01-01

These proceedings contain the lectures presented at the named winter school. They deal with the application of dynamical systems to accelerator theory. Especially considered are the statistical description of charged-beam plasmas, integrable and nonintegrable Hamiltonian systems, single particle dynamics and nonlinear resonances in circular accelerators, nonlinear dynamics aspects of modern storage rings, nonlinear beam-beam resonances, synchro-betatron resonances, observations of the beam-beam interactions, the dynamics of the beam-beam interactions, beam-beam simulations, the perturbation method in nonlinear dynamics, theories of statistical equilibrium in electron-positron storage rings, nonlinear dissipative phenomena in electron storage rings, the dynamical aperture, the transition to chaos for area-preserving maps, special processors for particle tracking, algorithms for tracking of charged particles in circular accelerators, the breakdown of stability, and a personal perspective of nonlinear dynamics. (HSI).

Dynamic Latent Classification Model

DEFF Research Database (Denmark)

Zhong, Shengtong; Martínez, Ana M.; Nielsen, Thomas Dyhre

as possible. Motivated by this problem setting, we propose a generative model for dynamic classification in continuous domains. At each time point the model can be seen as combining a naive Bayes model with a mixture of factor analyzers (FA). The latent variables of the FA are used to capture the dynamics...

Dynamic Calibration and Verification Device of Measurement System for Dynamic Characteristic Coefficients of Sliding Bearing

Science.gov (United States)

Chen, Runlin; Wei, Yangyang; Shi, Zhaoyang; Yuan, Xiaoyang

2016-01-01

The identification accuracy of dynamic characteristics coefficients is difficult to guarantee because of the errors of the measurement system itself. A novel dynamic calibration method of measurement system for dynamic characteristics coefficients is proposed in this paper to eliminate the errors of the measurement system itself. Compared with the calibration method of suspension quality, this novel calibration method is different because the verification device is a spring-mass system, which can simulate the dynamic characteristics of sliding bearing. The verification device is built, and the calibration experiment is implemented in a wide frequency range, in which the bearing stiffness is simulated by the disc springs. The experimental results show that the amplitude errors of this measurement system are small in the frequency range of 10 Hz–100 Hz, and the phase errors increase along with the increasing of frequency. It is preliminarily verified by the simulated experiment of dynamic characteristics coefficients identification in the frequency range of 10 Hz–30 Hz that the calibration data in this frequency range can support the dynamic characteristics test of sliding bearing in this frequency range well. The bearing experiments in greater frequency ranges need higher manufacturing and installation precision of calibration device. Besides, the processes of calibration experiments should be improved. PMID:27483283

Dynamics of vehicle-road coupled system

CERN Document Server

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 dynamics new directions theoretical aspects

CERN Document Server

Ugalde, Edgardo

2015-01-01

This book, along with its companion volume, Nonlinear Dynamics New Directions: Models and Applications, covers topics ranging from fractal analysis to very specific applications of the theory of dynamical systems to biology. This first volume is devoted to fundamental aspects and includes a number of important new contributions as well as some review articles that emphasize new development prospects. The second volume contains mostly new applications of the theory of dynamical systems to both engineering and biology. The topics addressed in the two volumes include a rigorous treatment of fluctuations in dynamical systems, topics in fractal analysis, studies of the transient dynamics in biological networks, synchronization in lasers, and control of chaotic systems, among others. This book also: ·         Presents a rigorous treatment of fluctuations in dynamical systems and explores a range of topics in fractal analysis, among other fundamental topics ·         Features recent developments on...

Brownian dynamics with hydrodynamic interactions

International Nuclear Information System (INIS)

Ermak, D.L.; McCammon, J.A.

1978-01-01

A method for simulating the Brownian dynamics of N particles with the inclusion of hydrodynamic interactions is described. The particles may also be subject to the usual interparticle or external forces (e.g., electrostatic) which have been included in previous methods for simulating Brownian dynamics of particles in the absence of hydrodynamic interactions. The present method is derived from the Langevin equations for the N particle assembly, and the results are shown to be consistent with the corresponding Fokker--Planck results. Sample calculations on small systems illustrate the importance of including hydrodynamic interactions in Brownian dynamics simulations. The method should be useful for simulation studies of diffusion limited reactions, polymer dynamics, protein folding, particle coagulation, and other phenomena in solution

Applied dynamics

CERN Document Server

Schiehlen, Werner

2014-01-01

Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.

Towards a Population Dynamics Theory for Evolutionary Computing: Learning from Biological Population Dynamics in Nature

Science.gov (United States)

Ma, Zhanshan (Sam)

In evolutionary computing (EC), population size is one of the critical parameters that a researcher has to deal with. Hence, it was no surprise that the pioneers of EC, such as De Jong (1975) and Holland (1975), had already studied the population sizing from the very beginning of EC. What is perhaps surprising is that more than three decades later, we still largely depend on the experience or ad-hoc trial-and-error approach to set the population size. For example, in a recent monograph, Eiben and Smith (2003) indicated: "In almost all EC applications, the population size is constant and does not change during the evolutionary search." Despite enormous research on this issue in recent years, we still lack a well accepted theory for population sizing. In this paper, I propose to develop a population dynamics theory forEC with the inspiration from the population dynamics theory of biological populations in nature. Essentially, the EC population is considered as a dynamic system over time (generations) and space (search space or fitness landscape), similar to the spatial and temporal dynamics of biological populations in nature. With this conceptual mapping, I propose to 'transplant' the biological population dynamics theory to EC via three steps: (i) experimentally test the feasibility—whether or not emulating natural population dynamics improves the EC performance; (ii) comparatively study the underlying mechanisms—why there are improvements, primarily via statistical modeling analysis; (iii) conduct theoretical analysis with theoretical models such as percolation theory and extended evolutionary game theory that are generally applicable to both EC and natural populations. This article is a summary of a series of studies we have performed to achieve the general goal [27][30]-[32]. In the following, I start with an extremely brief introduction on the theory and models of natural population dynamics (Sections 1 & 2). In Sections 4 to 6, I briefly discuss three

Nonlinear dynamics based digital logic and circuits.

Science.gov (United States)

Kia, Behnam; Lindner, John F; Ditto, William L

2015-01-01

We discuss the role and importance of dynamics in the brain and biological neural networks and argue that dynamics is one of the main missing elements in conventional Boolean logic and circuits. We summarize a simple dynamics based computing method, and categorize different techniques that we have introduced to realize logic, functionality, and programmability. We discuss the role and importance of coupled dynamics in networks of biological excitable cells, and then review our simple coupled dynamics based method for computing. In this paper, for the first time, we show how dynamics can be used and programmed to implement computation in any given base, including but not limited to base two.

Quantum net dynamics

International Nuclear Information System (INIS)

Finkelstein, D.

1989-01-01

The quantum net unifies the basic principles of quantum theory and relativity in a quantum spacetime having no ultraviolet infinities, supporting the Dirac equation, and having the usual vacuum as a quantum condensation. A correspondence principle connects nets to Schwinger sources and further unifies the vertical structure of the theory, so that the functions of the many hierarchic levels of quantum field theory (predicate algebra, set theory, topology,hor-ellipsis, quantum dynamics) are served by one in quantum net dynamics

Complexified dynamical systems

International Nuclear Information System (INIS)

Bender, Carl M; Holm, Darryl D; Hook, Daniel W

2007-01-01

Many dynamical systems, such as the Lotka-Volterra predator-prey model and the Euler equations for the free rotation of a rigid body, are PT symmetric. The standard and well-known real solutions to such dynamical systems constitute an infinitessimal subclass of the full set of complex solutions. This paper examines a subset of the complex solutions that contains the real solutions, namely those having PT symmetry. The condition of PT symmetry selects out complex solutions that are periodic. (fast track communication)

Dynamic Model Averaging in Large Model Spaces Using Dynamic Occam's Window.

Science.gov (United States)

Onorante, Luca; Raftery, Adrian E

2016-01-01

Bayesian model averaging has become a widely used approach to accounting for uncertainty about the structural form of the model generating the data. When data arrive sequentially and the generating model can change over time, Dynamic Model Averaging (DMA) extends model averaging to deal with this situation. Often in macroeconomics, however, many candidate explanatory variables are available and the number of possible models becomes too large for DMA to be applied in its original form. We propose a new method for this situation which allows us to perform DMA without considering the whole model space, but using a subset of models and dynamically optimizing the choice of models at each point in time. This yields a dynamic form of Occam's window. We evaluate the method in the context of the problem of nowcasting GDP in the Euro area. We find that its forecasting performance compares well with that of other methods.

Dynamic behaviors of spin-1/2 bilayer system within Glauber-type stochastic dynamics based on the effective-field theory

International Nuclear Information System (INIS)

Ertaş, Mehmet; Kantar, Ersin; Keskin, Mustafa

2014-01-01

The dynamic phase transitions (DPTs) and dynamic phase diagrams of the kinetic spin-1/2 bilayer system in the presence of a time-dependent oscillating external magnetic field are studied by using Glauber-type stochastic dynamics based on the effective-field theory with correlations for the ferromagnetic/ferromagnetic (FM/FM), antiferromagnetic/ferromagnetic (AFM/FM) and antiferromagnetic/antiferromagnetic (AFM/AFM) interactions. The time variations of average magnetizations and the temperature dependence of the dynamic magnetizations are investigated. The dynamic phase diagrams for the amplitude of the oscillating field versus temperature were presented. The results are compared with the results of the same system within Glauber-type stochastic dynamics based on the mean-field theory. - Highlights: • The Ising bilayer system is investigated within the Glauber dynamics based on EFT. • The time variations of average order parameters to find phases are studied. • The dynamic phase diagrams are found for the different interaction parameters. • The system displays the critical points as well as a re-entrant behavior

Dynamic behaviors of spin-1/2 bilayer system within Glauber-type stochastic dynamics based on the effective-field theory

Energy Technology Data Exchange (ETDEWEB)

Ertaş, Mehmet; Kantar, Ersin, E-mail: ersinkantar@erciyes.edu.tr; Keskin, Mustafa

2014-05-01

The dynamic phase transitions (DPTs) and dynamic phase diagrams of the kinetic spin-1/2 bilayer system in the presence of a time-dependent oscillating external magnetic field are studied by using Glauber-type stochastic dynamics based on the effective-field theory with correlations for the ferromagnetic/ferromagnetic (FM/FM), antiferromagnetic/ferromagnetic (AFM/FM) and antiferromagnetic/antiferromagnetic (AFM/AFM) interactions. The time variations of average magnetizations and the temperature dependence of the dynamic magnetizations are investigated. The dynamic phase diagrams for the amplitude of the oscillating field versus temperature were presented. The results are compared with the results of the same system within Glauber-type stochastic dynamics based on the mean-field theory. - Highlights: • The Ising bilayer system is investigated within the Glauber dynamics based on EFT. • The time variations of average order parameters to find phases are studied. • The dynamic phase diagrams are found for the different interaction parameters. • The system displays the critical points as well as a re-entrant behavior.

Diagnosis of renal cell cancer by dynamic MRI

International Nuclear Information System (INIS)

Togami, Izumi; Kitagawa, Takahiro; Katoh, Katsuya

1992-01-01

Dynamic MRI was performed in 15 cases (16 lesions) of renal cell cancer. The enhanced pattern of the tumor was mainly evaluated and findings were compared with these of dynamic CT and renal angiography. Enhanced patterns on dynamic MRI and dynamic CT were similar, but each phase on dynamic MRI tended to be prolonged compared with dynamic CT. Many hypervascular tumors on renal angiography had prominent enhancement in an early phase on dynamic MRI, but there was no prominent enhancement in cases with tumor thrombi in the renal vein or IVC. All hypovascular tumors were enhanced to some degree without exception on dynamic MRI. Dynamic MRI is considered to be useful for the evaluation of the characterization, especially vascularity, of renal cell cancer, but we should pay attention to the differential diagnosis from other tumor in atypical cases because its enhanced patterns are various on dynamic MRI. (author)

Pseudo-random number generation for Brownian Dynamics and Dissipative Particle Dynamics simulations on GPU devices

International Nuclear Information System (INIS)

Phillips, Carolyn L.; Anderson, Joshua A.; Glotzer, Sharon C.

2011-01-01

Highlights: → Molecular Dynamics codes implemented on GPUs have achieved two-order of magnitude computational accelerations. → Brownian Dynamics and Dissipative Particle Dynamics simulations require a large number of random numbers per time step. → We introduce a method for generating small batches of pseudorandom numbers distributed over many threads of calculations. → With this method, Dissipative Particle Dynamics is implemented on a GPU device without requiring thread-to-thread communication. - Abstract: Brownian Dynamics (BD), also known as Langevin Dynamics, and Dissipative Particle Dynamics (DPD) are implicit solvent methods commonly used in models of soft matter and biomolecular systems. The interaction of the numerous solvent particles with larger particles is coarse-grained as a Langevin thermostat is applied to individual particles or to particle pairs. The Langevin thermostat requires a pseudo-random number generator (PRNG) to generate the stochastic force applied to each particle or pair of neighboring particles during each time step in the integration of Newton's equations of motion. In a Single-Instruction-Multiple-Thread (SIMT) GPU parallel computing environment, small batches of random numbers must be generated over thousands of threads and millions of kernel calls. In this communication we introduce a one-PRNG-per-kernel-call-per-thread scheme, in which a micro-stream of pseudorandom numbers is generated in each thread and kernel call. These high quality, statistically robust micro-streams require no global memory for state storage, are more computationally efficient than other PRNG schemes in memory-bound kernels, and uniquely enable the DPD simulation method without requiring communication between threads.

Neural Population Dynamics during Reaching Are Better Explained by a Dynamical System than Representational Tuning.

Science.gov (United States)

Michaels, Jonathan A; Dann, Benjamin; Scherberger, Hansjörg

2016-11-01

Recent models of movement generation in motor cortex have sought to explain neural activity not as a function of movement parameters, known as representational models, but as a dynamical system acting at the level of the population. Despite evidence supporting this framework, the evaluation of representational models and their integration with dynamical systems is incomplete in the literature. Using a representational velocity-tuning based simulation of center-out reaching, we show that incorporating variable latency offsets between neural activity and kinematics is sufficient to generate rotational dynamics at the level of neural populations, a phenomenon observed in motor cortex. However, we developed a covariance-matched permutation test (CMPT) that reassigns neural data between task conditions independently for each neuron while maintaining overall neuron-to-neuron relationships, revealing that rotations based on the representational model did not uniquely depend on the underlying condition structure. In contrast, rotations based on either a dynamical model or motor cortex data depend on this relationship, providing evidence that the dynamical model more readily explains motor cortex activity. Importantly, implementing a recurrent neural network we demonstrate that both representational tuning properties and rotational dynamics emerge, providing evidence that a dynamical system can reproduce previous findings of representational tuning. Finally, using motor cortex data in combination with the CMPT, we show that results based on small numbers of neurons or conditions should be interpreted cautiously, potentially informing future experimental design. Together, our findings reinforce the view that representational models lack the explanatory power to describe complex aspects of single neuron and population level activity.

Formal analysis of design process dynamics

NARCIS (Netherlands)

Bosse, T.; Jonker, C.M.; Treur, J.

2010-01-01

This paper presents a formal analysis of design process dynamics. Such a formal analysis is a prerequisite to come to a formal theory of design and for the development of automated support for the dynamics of design processes. The analysis was geared toward the identification of dynamic design

Formal Analysis of Design Process Dynamics

NARCIS (Netherlands)

Bosse, T.; Jonker, C.M.; Treur, J.

2010-01-01

This paper presents a formal analysis of design process dynamics. Such a formal analysis is a prerequisite to come to a formal theory of design and for the development of automated support for the dynamics of design processes. The analysis was geared toward the identification of dynamic design

Inventories and upstream gasoline price dynamics

NARCIS (Netherlands)

Kuper, Gerard H.

This paper sheds new light on the asymmetric dynamics in upstream U.S. gasoline prices. The model is based on Pindyck's inventory model of commodity price dynamics. We show that asymmetry in gasoline price dynamics is caused by changes in the net marginal convenience yield: higher costs of marketing

Structural Dynamics, Vol. 9

DEFF Research Database (Denmark)

Nielsen, Søren R.K.

This book has been prepared for the course on Computational Dynamics given at the 8th semester at the structural program in civil engineering at Aalborg University.......This book has been prepared for the course on Computational Dynamics given at the 8th semester at the structural program in civil engineering at Aalborg University....

Pseudorotational dynamics of small molecular species

International Nuclear Information System (INIS)

Hagelberg, F.

2002-01-01

The electron nuclear dynamics (END) theory was designed to provide a full description of the dynamic development of the electronic system. It is independent of any potential energy surface constructions. The dynamic behavior of molecules close to the threshold of dissociation was the objective of this study. Thus, simulations based on END theory were performed with the aim to extend the current understanding of the dynamic features of pseudorotational into a non-adiabatic regime. Electron dynamics of triatomic species (H 3 + and Li 3 + ) in terms of electronic angular momentum expectation values were characterized. Finally, it is shown that the expansion coefficients which carry the information about the excitation content of the electronic system at any stage of the motional process can be calculated. (nevyjel)

Dynamics and computation in functional shifts

Science.gov (United States)

Namikawa, Jun; Hashimoto, Takashi

2004-07-01

We introduce a new type of shift dynamics as an extended model of symbolic dynamics, and investigate the characteristics of shift spaces from the viewpoints of both dynamics and computation. This shift dynamics is called a functional shift, which is defined by a set of bi-infinite sequences of some functions on a set of symbols. To analyse the complexity of functional shifts, we measure them in terms of topological entropy, and locate their languages in the Chomsky hierarchy. Through this study, we argue that considering functional shifts from the viewpoints of both dynamics and computation gives us opposite results about the complexity of systems. We also describe a new class of shift spaces whose languages are not recursively enumerable.

Dynamics and Thermodynamics of Transthyretin Association from Molecular Dynamics Simulations

Directory of Open Access Journals (Sweden)

Cedrix J. Dongmo Foumthuim

2018-01-01

Full Text Available Molecular dynamics simulations are used in this work to probe the structural stability and the dynamics of engineered mutants of transthyretin (TTR, i.e., the double mutant F87M/L110M (MT-TTR and the triple mutant F87M/L110M/S117E (3M-TTR, in relation to wild-type. Free energy analysis from end-point simulations and statistical effective energy functions are used to analyze trajectories, revealing that mutations do not have major impact on protein structure but rather on protein association, shifting the equilibria towards dissociated species. The result is confirmed by the analysis of 3M-TTR which shows dissociation within the first 10 ns of the simulation, indicating that contacts are lost at the dimer-dimer interface, whereas dimers (formed by monomers which pair to form two extended β-sheets appear fairly stable. Overall the simulations provide a detailed view of the dynamics and thermodynamics of wild-type and mutant transthyretins and a rationale of the observed effects.

DYNAMICS OF FINANCIAL SYSTEM: A SYSTEM DYNAMICS APPROACH

Directory of Open Access Journals (Sweden)

Girish K Nair

2013-01-01

Full Text Available There are several ratios which define the financial health of an organization but the importance of Net cash flow, Gross income, Net income, Pending bills, Receivable bills, Debt, and Book value can never be undermined as they give the exact picture of the financial condition. While there are several approaches to study the dynamics of these variables, system dynamics based modelling and simulation is one of the modern techniques. The paper explores this method to simulate the before mentioned parameters during production capacity expansion in an electronic industry. Debt and Book value have shown a non-linear pattern of variation which is discussed. The model can be used by the financial experts as a decision support tool in arriving at conclusions in connection to the expansion plans of the organization.

Quantum dynamical entropy revisited

International Nuclear Information System (INIS)

Hudetz, T.

1996-10-01

We define a new quantum dynamical entropy, which is a 'hybrid' of the closely related, physically oriented entropy introduced by Alicki and Fannes in 1994, and of the mathematically well-developed, single-argument entropy introduced by Connes, Narnhofer and Thirring in 1987. We show that this new quantum dynamical entropy has many properties similar to the ones of the Alicki-Fannes entropy, and also inherits some additional properties from the CNT entropy. In particular, the 'hybrid' entropy interpolates between the two different ways in which both the AF and the CNT entropy of the shift automorphism on the quantum spin chain agree with the usual quantum entropy density, resulting in even better agreement. Also, the new quantum dynamical entropy generalizes the classical dynamical entropy of Kolmogorov and Sinai in the same way as does the AF entropy. Finally, we estimate the 'hybrid' entropy both for the Powers-Price shift systems and for the noncommutative Arnold map on the irrational rotation C * -algebra, leaving some interesting open problems. (author)

Structural dynamics in FBR

International Nuclear Information System (INIS)

Bhoje, S.B.

2003-01-01

In view of thin walled large diameter shell structures with associated fluid effects, structural dynamics problems are very critical in a fast breeder reactor. Structural characteristics and consequent structural dynamics problems in typical pool type Fast Breeder Reactor are highlighted. A few important structural dynamics problems are pump induced as well as flow induced vibrations, seismic excitations, pressure transients in the intermediate heat exchangers and pipings due to a large sodium water reaction in the steam generator, and core disruptive accident loadings. The vibration problems which call for identification of excitation forces, formulation of special governing equations and detailed analysis with fluid structure interaction and sloshing effects, particularly for the components such as PSP, inner vessel, CP, CSRDM and TB are elaborated. Seismic design issues are presented in a comprehensive way. Other transient loadings which are specific to FBR, resulting from sodium-water reaction and core disruptive accident are highlighted. A few important results of theoretical as well as experimental works carried out for 500 MWe Prototype Fast Breeder Reactor (PFBR), in the domain of structural dynamics are presented. (author)

77 FR 41808 - General Dynamics Itronix Corporation, a Subsidiary of General Dynamics Corporation, Including...

Science.gov (United States)

2012-07-16

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-81,448] General Dynamics Itronix Corporation, a Subsidiary of General Dynamics Corporation, Including Remote Workers Reporting to Sunrise, FL..., 2012, a State Workforce Office requested administrative reconsideration of the negative determination...

Geophysical fluid dynamics

CERN Document Server

Pedlosky, Joseph

1982-01-01

The content of this book is based, largely, on the core curriculum in geophys­ ical fluid dynamics which land my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same tim...

Geophysical fluid dynamics

CERN Document Server

Pedlosky, Joseph

1979-01-01

The content of this book is based, largely, on the core curriculum in geophys­ ical fluid dynamics which I and my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same ti...

Dynamical symmetries for fermions

International Nuclear Information System (INIS)

Guidry, M.

1989-01-01

An introduction is given to the Fermion Dynamical Symmetry Model (FDSM). The analytical symmetry limits of the model are then applied to the calculation of physical quantities such as ground-state masses and B(E 2 ) values in heavy nuclei. These comparisons with data provide strong support for a new principle of collective motion, the Dynamical Pauli Effect, and suggest that dynamical symmetries which properly account for the pauli principle are much more persistent in nuclear structure than the corresponding boson symmetries. Finally, we present an assessment of criticisms which have been voiced concerning the FDSM, and a discussion of new phenomena and ''exotic spectroscopy'' which may be suggested by the model. 14 refs., 8 figs., 4 tabs

Stabilities and Dynamics of Protein Folding Nuclei by Molecular Dynamics Simulation

Science.gov (United States)

Song, Yong-Shun; Zhou, Xin; Zheng, Wei-Mou; Wang, Yan-Ting

2017-07-01

To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics (MD) simulation in aqueous solution four fragments cut out of a protein G, including one α-helix (seqB: KVFKQYAN), two β-turns (seqA: LNGKTLKG and seqC: YDDATKTF), and one β-strand (seqD: DGEWTYDD). The Markov State Model clustering method combined with the coarse-grained conformation letters method are employed to analyze the data sampled from 2-μs equilibrium MD simulation trajectories. We find that seqA and seqB have more stable structures than their native structures which become metastable when cut out of the protein structure. As expected, seqD alone is flexible and does not have a stable structure. Throughout our simulations, the native structure of seqC is stable but cannot be reached if starting from a structure other than the native one, implying a funnel-shape free energy landscape of seqC in aqueous solution. All the above results suggest that different nuclei have different formation dynamics during protein folding, which may have a major contribution to the hierarchy of protein folding dynamics. Supported by the National Basic Research Program of China under Grant No. 2013CB932804, the National Natural Science Foundation of China under Grant No. 11421063, and the CAS Biophysics Interdisciplinary Innovation Team Project

Dynamic skin deformation simulation using musculoskeletal model and soft tissue dynamics

Institute of Scientific and Technical Information of China (English)

Akihiko Murai; Q. Youn Hong; Katsu Yamane; Jessica K. Hodgins

2017-01-01

Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin deformations that must move appropriately for the character design. In this paper, we present an algorithm that generates natural, dynamic, and detailed skin deformation (movement and jiggle) from joint angle data sequences. The algorithm has two steps: identification of parameters for a quasi-static muscle deformation model, and simulation of skin deformation. In the identification step, we identify the model parameters using a musculoskeletal model and a short sequence of skin deformation data captured via a dense marker set. The simulation step first uses the quasi-static muscle deformation model to obtain the quasi-static muscle shape at each frame of the given motion sequence (slow jump). Dynamic skin deformation is then computed by simulating the passive muscle and soft tissue dynamics modeled as a mass–spring–damper system. Having obtained the model parameters, we can simulate dynamic skin deformations for subjects with similar body types from new motion data. We demonstrate our method by creating skin deformations for muscle co-contraction and external impacts from four different behaviors captured as skeletal motion capture data. Experimental results show that the simulated skin deformations are quantitatively and qualitatively similar to measured actual skin deformations.

Dynamic skin deformation simulation using musculoskeletal model and soft tissue dynamics

Institute of Scientific and Technical Information of China (English)

Akihiko Murai; Q.Youn Hong; Katsu Yamane; Jessica K.Hodgins

2017-01-01

Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin deformations that must move appropriately for the character design. In this paper, we present an algorithm that generates natural, dynamic, and detailed skin deformation(movement and jiggle) from joint angle data sequences. The algorithm has two steps: identification of parameters for a quasi-static muscle deformation model, and simulation of skin deformation. In the identification step, we identify the model parameters using a musculoskeletal model and a short sequence of skin deformation data captured via a dense marker set. The simulation step first uses the quasi-static muscle deformation model to obtain the quasi-static muscle shape at each frame of the given motion sequence(slow jump). Dynamic skin deformation is then computed by simulating the passive muscle and soft tissue dynamics modeled as a mass–spring–damper system. Having obtained the model parameters, we can simulate dynamic skin deformations for subjects with similar body types from new motion data. We demonstrate our method by creating skin deformations for muscle co-contraction and external impacts from four different behaviors captured as skeletal motion capture data. Experimental results show that the simulated skin deformations are quantitatively and qualitatively similar to measured actual skin deformations.

Dynamical systems, attractors, and neural circuits.

Science.gov (United States)

Miller, Paul

2016-01-01

Biology is the study of dynamical systems. Yet most of us working in biology have limited pedagogical training in the theory of dynamical systems, an unfortunate historical fact that can be remedied for future generations of life scientists. In my particular field of systems neuroscience, neural circuits are rife with nonlinearities at all levels of description, rendering simple methodologies and our own intuition unreliable. Therefore, our ideas are likely to be wrong unless informed by good models. These models should be based on the mathematical theories of dynamical systems since functioning neurons are dynamic-they change their membrane potential and firing rates with time. Thus, selecting the appropriate type of dynamical system upon which to base a model is an important first step in the modeling process. This step all too easily goes awry, in part because there are many frameworks to choose from, in part because the sparsely sampled data can be consistent with a variety of dynamical processes, and in part because each modeler has a preferred modeling approach that is difficult to move away from. This brief review summarizes some of the main dynamical paradigms that can arise in neural circuits, with comments on what they can achieve computationally and what signatures might reveal their presence within empirical data. I provide examples of different dynamical systems using simple circuits of two or three cells, emphasizing that any one connectivity pattern is compatible with multiple, diverse functions.

Dynamic Approaches for Multichoice Solutions

Directory of Open Access Journals (Sweden)

Yu-Hsien Liao

2011-01-01

Full Text Available Based on alternative reduced games, several dynamic approaches are proposed to show how the three extended Shapley values can be reached dynamically from arbitrary efficient payoff vectors on multichoice games.

Dynamical heterogeneities of rotational motion in room temperature ionic liquids evidenced by molecular dynamics simulations

Science.gov (United States)

Usui, Kota; Hunger, Johannes; Bonn, Mischa; Sulpizi, Marialore

2018-05-01

Room temperature ionic liquids (RTILs) have been shown to exhibit spatial heterogeneity or structural heterogeneity in the sense that they form hydrophobic and ionic domains. Yet studies of the relationship between this structural heterogeneity and the ˜picosecond motion of the molecular constituents remain limited. In order to obtain insight into the time scales relevant to this structural heterogeneity, we perform molecular dynamics simulations of a series of RTILs. To investigate the relationship between the structures, i.e., the presence of hydrophobic and ionic domains, and the dynamics, we gradually increase the size of the hydrophobic part of the cation from ethylammonium nitrate (EAN), via propylammonium nitrate (PAN), to butylammonium nitrate (BAN). The two ends of the organic cation, namely, the charged Nhead-H group and the hydrophobic Ctail-H group, exhibit rotational dynamics on different time scales, evidencing dynamical heterogeneity. The dynamics of the Nhead-H group is slower because of the strong coulombic interaction with the nitrate counter-ionic anions, while the dynamics of the Ctail-H group is faster because of the weaker van der Waals interaction with the surrounding atoms. In particular, the rotation of the Nhead-H group slows down with increasing cationic chain length, while the rotation of the Ctail-H group shows little dependence on the cationic chain length, manifesting that the dynamical heterogeneity is enhanced with a longer cationic chain. The slowdown of the Nhead-H group with increasing cationic chain length is associated with a lower number of nitrate anions near the Nhead-H group, which presumably results in the increase of the energy barrier for the rotation. The sensitivity of the Nhead-H rotation to the number of surrounding nitrate anions, in conjunction with the varying number of nitrate anions, gives rise to a broad distribution of Nhead-H reorientation times. Our results suggest that the asymmetry of the cations and the

Nonlinear dynamics in Nuclotron

International Nuclear Information System (INIS)

Dinev, D.

1997-01-01

The paper represents an extensive study of the nonlinear beam dynamics in the Nuclotron. Chromatic effects, including the dependence of the betatron tunes on the amplitude, and chromatic perturbations have been investigated taking into account the measured field imperfections. Beam distortion, smear, dynamic aperture and nonlinear acceptance have been calculated for different particle energies and betatron tunes

Dynamic Diversification in Corporate Credit

DEFF Research Database (Denmark)

Christoffersen, Peter; Jacobs, Kris; Jin, Xisong

We characterize diversification in corporate credit using a new class of dynamic copula models which can capture dynamic dependence and asymmetry in large samples of firms. We also document important differences between credit spread and equity return dependence dynamics. Modeling a decade...... the crisis and remain high as well. The most important shocks to credit dependence occur in August of 2007 and in August of 2011, but interestingly these dates are not associated with significant changes to median credit spreads....

Introduction to stochastic dynamic programming

CERN Document Server

Ross, Sheldon M; Lukacs, E

1983-01-01

Introduction to Stochastic Dynamic Programming presents the basic theory and examines the scope of applications of stochastic dynamic programming. The book begins with a chapter on various finite-stage models, illustrating the wide range of applications of stochastic dynamic programming. Subsequent chapters study infinite-stage models: discounting future returns, minimizing nonnegative costs, maximizing nonnegative returns, and maximizing the long-run average return. Each of these chapters first considers whether an optimal policy need exist-providing counterexamples where appropriate-and the

Chaotic dynamics in accelerator physics

International Nuclear Information System (INIS)

Cary, J.R.

1992-01-01

Substantial progress was in several areas of accelerator dynamics. For developing understanding of longitudinal adiabatic dynamics, and for creating efficiency enhancements of recirculating free-electron lasers, was substantially completed. A computer code for analyzing the critical KAM tori that bound the dynamic aperture in circular machines was developed. Studies of modes that arise due to the interaction of coating beams with a narrow-spectrum impedance have begun. During this research educational and research ties with the accelerator community at large have been strengthened

Molecular dynamics studies of the dynamics of supercooled Lennard-Jones liquids

International Nuclear Information System (INIS)

De Leeuw, S.W.; Brakkee, M.J.D.

1990-01-01

Results are presented of molecular dynamics experiments, in which the Lennard-Jones liquid is cooled isobarically into the metastable temperature region below the freezing temperature. The variation of the density-density and transverse current correlation functions with temperature is studied. We observed a power-law behaviour for the temperature dependence of dynamical properties (viscosity and coefficienty of self-diffusion) with an exponent in good agreement with prediction of mode coupling theories and recent experimental results. (author). 23 refs, 5 figs

The dynamics of general developmental mechanisms : From Piaget and Vygotsky to dynamic systems models

NARCIS (Netherlands)

van Geert, P

Dynamic systems theory conceives of development as a self-organizational process. Both complexity and order emerge as a product of elementary principles of interaction between components involved in the developmental process. This article presents a dynamic systems model based on a general dual

Conformational dynamics data bank: a database for conformational dynamics of proteins and supramolecular protein assemblies.

Science.gov (United States)

Kim, Do-Nyun; Altschuler, Josiah; Strong, Campbell; McGill, Gaël; Bathe, Mark

2011-01-01

The conformational dynamics data bank (CDDB, http://www.cdyn.org) is a database that aims to provide comprehensive results on the conformational dynamics of high molecular weight proteins and protein assemblies. Analysis is performed using a recently introduced coarse-grained computational approach that is applied to the majority of structures present in the electron microscopy data bank (EMDB). Results include equilibrium thermal fluctuations and elastic strain energy distributions that identify rigid versus flexible protein domains generally, as well as those associated with specific functional transitions, and correlations in molecular motions that identify molecular regions that are highly coupled dynamically, with implications for allosteric mechanisms. A practical web-based search interface enables users to easily collect conformational dynamics data in various formats. The data bank is maintained and updated automatically to include conformational dynamics results for new structural entries as they become available in the EMDB. The CDDB complements static structural information to facilitate the investigation and interpretation of the biological function of proteins and protein assemblies essential to cell function.

Dynamic stiffness of suction caissons

DEFF Research Database (Denmark)

Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

This report concerns the dynamic soil-structure interaction of steel suction caissons applied as foundations for offshore wind turbines. An emphasis is put on torsional vibrations and coupled sliding/rocking motion, and the influence of the foundation geometry and the properties of the surrounding...... soil is examined. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency-dependent coefficients corresponding to the different degrees of freedom. The dynamic stiffness coefficients...... for the skirted foundation are evaluated by means of a three-dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been...

Dynamics of High-Resolution Networks

DEFF Research Database (Denmark)

Sekara, Vedran

the unprecedented amounts of information collected by mobile phones to gain detailed insight into the dynamics of social systems. This dissertation presents an unparalleled data collection campaign, collecting highly detailed traces for approximately 1000 people over the course of multiple years. The availability...... are we all affected by an ever changing network structure? Answering these questions will enrich our understanding of ourselves, our organizations, and our societies. Yet, mapping the dynamics of social networks has traditionally been an arduous undertaking. Today, however, it is possible to use...... of such dynamic maps allows us to probe the underlying social network and understand how individuals interact and form lasting friendships. More importantly, these highly detailed dynamic maps provide us new perspectives at traditional problems and allow us to quantify and predict human life....

Dynamics

CERN Document Server

Goodman, Lawrence E

2001-01-01

Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

Selection-Mutation Dynamics of Signaling Games

Directory of Open Access Journals (Sweden)

Josef Hofbauer

2015-01-01

Full Text Available We study the structure of the rest points of signaling games and their dynamic behavior under selection-mutation dynamics by taking the case of three signals as our canonical example. Many rest points of the replicator dynamics of signaling games are not isolated and, therefore, not robust under perturbations. However, some of them attract open sets of initial conditions. We prove the existence of certain rest points of the selection-mutation dynamics close to Nash equilibria of the signaling game and show that all but the perturbed rest points close to strict Nash equilibria are dynamically unstable. This is an important result for the evolution of signaling behavior, since it shows that the second-order forces that are governed by mutation can increase the chances of successful signaling.

Intermittent many-body dynamics at equilibrium

Science.gov (United States)

Danieli, C.; Campbell, D. K.; Flach, S.

2017-06-01

The equilibrium value of an observable defines a manifold in the phase space of an ergodic and equipartitioned many-body system. A typical trajectory pierces that manifold infinitely often as time goes to infinity. We use these piercings to measure both the relaxation time of the lowest frequency eigenmode of the Fermi-Pasta-Ulam chain, as well as the fluctuations of the subsequent dynamics in equilibrium. The dynamics in equilibrium is characterized by a power-law distribution of excursion times far off equilibrium, with diverging variance. Long excursions arise from sticky dynamics close to q -breathers localized in normal mode space. Measuring the exponent allows one to predict the transition into nonergodic dynamics. We generalize our method to Klein-Gordon lattices where the sticky dynamics is due to discrete breathers localized in real space.

Color molecular dynamics for dense matter

International Nuclear Information System (INIS)

Maruyama, Toshiki; Hatsuda, Tetsuo

2000-01-01

We propose a microscopic approach for quark many-body system based on molecular dynamics. Using color confinement and one-gluon exchange potentials together with meson exchange potentials between quarks, we construct nucleons and nuclear/quark matter. Dynamical transition between confinement and deconfinement phases are studied at high baryon density with this molecular dynamics simulation. (author)

Dynamic computed tomography findings in cerebrovascular diseases

International Nuclear Information System (INIS)

Araki, Yutaka; Tomoda, Kaname; Kariya, Mitsumasa; Mori, Shigeru; Mitomo, Masanori.

1988-01-01

Dynamic CT was performed with 41 patients with the clinically diagnosed cerebrovascular diseases. A visual evaluation based on the dynamic CT images classified six patterns of brain parenchymal enhancement, especially four patterns of which could only be detected by dynamic CT technique. Dynamic CT was proved of great value in detecting regional cerebral tissue filled by collaterals in retrograde fashion because of the occlusion of main arteries, namely brain tissue perfusion of internal carotid occlusion disease and moyamoya disease was best understood by dynamic CT with adequate resolution. (author)

Performance of dynamic safety barriers-Structuring, modelling and visualization

OpenAIRE

Wikdahl, Olga

2014-01-01

The main objective of this master thesis is to discuss performance of dynamic safety barriers. A comprehensive literature review is performed in order to get understanding what dynamic safety barrier is. Three different concepts of dynamic safety barriers based on various meanings of dynamic were derived from the literature review: - dynamic safety barriers related to motion or physical force - dynamic safety barriers as updated barriers from dynamic risk analysis - dynamic safety ...

From point process observations to collective neural dynamics: Nonlinear Hawkes process GLMs, low-dimensional dynamics and coarse graining.

Science.gov (United States)

Truccolo, Wilson

2016-11-01

This review presents a perspective on capturing collective dynamics in recorded neuronal ensembles based on multivariate point process models, inference of low-dimensional dynamics and coarse graining of spatiotemporal measurements. A general probabilistic framework for continuous time point processes reviewed, with an emphasis on multivariate nonlinear Hawkes processes with exogenous inputs. A point process generalized linear model (PP-GLM) framework for the estimation of discrete time multivariate nonlinear Hawkes processes is described. The approach is illustrated with the modeling of collective dynamics in neocortical neuronal ensembles recorded in human and non-human primates, and prediction of single-neuron spiking. A complementary approach to capture collective dynamics based on low-dimensional dynamics ("order parameters") inferred via latent state-space models with point process observations is presented. The approach is illustrated by inferring and decoding low-dimensional dynamics in primate motor cortex during naturalistic reach and grasp movements. Finally, we briefly review hypothesis tests based on conditional inference and spatiotemporal coarse graining for assessing collective dynamics in recorded neuronal ensembles. Published by Elsevier Ltd.

Hierarchical nonlinear dynamics of human attention.

Science.gov (United States)

Rabinovich, Mikhail I; Tristan, Irma; Varona, Pablo

2015-08-01

Attention is the process of focusing mental resources on a specific cognitive/behavioral task. Such brain dynamics involves different partially overlapping brain functional networks whose interconnections change in time according to the performance stage, and can be stimulus-driven or induced by an intrinsically generated goal. The corresponding activity can be described by different families of spatiotemporal discrete patterns or sequential dynamic modes. Since mental resources are finite, attention modalities compete with each other at all levels of the hierarchy, from perception to decision making and behavior. Cognitive activity is a dynamical process and attention possesses some universal dynamical characteristics. Thus, it is time to apply nonlinear dynamical theory for the description and prediction of hierarchical attentional tasks. Such theory has to include the analyses of attentional control stability, the time cost of attention switching, the finite capacity of informational resources in the brain, and the normal and pathological bifurcations of attention sequential dynamics. In this paper we have integrated today's knowledge, models and results in these directions. Copyright © 2015 Elsevier Ltd. All rights reserved.

GIS and dynamic phenomena modeling

Czech Academy of Sciences Publication Activity Database

Klimešová, Dana

2006-01-01

Roč. 4, č. 4 (2006), s. 11-15 ISSN 0139-570X Institutional research plan: CEZ:AV0Z10750506 Keywords : dynamic modelling * temporal analysis * dynamics evaluation * temporal space Subject RIV: BC - Control Systems Theory

Microsoft Dynamics CRM 2011 cookbook

CERN Document Server

Bhattacharya, Dipankar

2013-01-01

This is a Cookbook with recipes aimed at all levels with lots of practical walkthroughs for virtualization techniques.This book is great for Dynamics CRM 2011 professionals who have a beginner level understanding of the system and are looking to get a good grounding in how to deploy, maintain, configure, and customize a Dynamics CRM 2011 application efficiently. It's assumed that the reader has a basic level understanding of IT infrastructure topologies along with functional knowledge of Dynamics CRM 2011 Sales, Marketing, and Services modules.

Dynamic Programming Foundations and Principles

CERN Document Server

Sniedovich, Moshe

2010-01-01

Focusing on the modeling and solution of deterministic multistage decision problems, this book looks at dynamic programming as a problem-solving optimization method. With over 400 useful references, this edition discusses the dynamic programming analysis of a problem, illustrates the rationale behind this analysis, and clarifies the theoretical grounds that justify the rationale. It also explains the meaning and role of the concept of state in dynamic programming, examines the purpose and function of the principle of optimality, and outlines solution strategies for problems defiant of conventi

Nonlinear Dynamic Phenomena in Mechanics

CERN Document Server

Warminski, Jerzy; Cartmell, Matthew P

2012-01-01

Nonlinear phenomena should play a crucial role in the design and control of engineering systems and structures as they can drastically change the prevailing dynamical responses. This book covers theoretical and applications-based problems of nonlinear dynamics concerned with both discrete and continuous systems of interest in civil and mechanical engineering. They include pendulum-like systems, slender footbridges, shape memory alloys, sagged elastic cables and non-smooth problems. Pendulums can be used as a dynamic absorber mounted in high buildings, bridges or chimneys. Geometrical nonlinear

Beam dynamics

International Nuclear Information System (INIS)

Abell, D; Adelmann, A; Amundson, J; Dragt, A; Mottershead, C; Neri, F; Pogorelov, I; Qiang, J; Ryne, R; Shalf, J; Siegerist, C; Spentzouris, P; Stern, E; Venturini, M; Walstrom, P

2006-01-01

We describe some of the accomplishments of the Beam Dynamics portion of the SciDAC Accelerator Science and Technology project. During the course of the project, our beam dynamics software has evolved from the era of different codes for each physical effect to the era of hybrid codes combining start-of-the-art implementations for multiple physical effects to the beginning of the era of true multi-physics frameworks. We describe some of the infrastructure that has been developed over the course of the project and advanced features of the most recent developments, the interplay betwen beam studies and simulations and applications to current machines at Fermilab. Finally we discuss current and future plans for simulations of the International Linear Collider

Advancing the Assessment of Dynamic Psychological Processes.

Science.gov (United States)

Wright, Aidan G C; Hopwood, Christopher J

2016-08-01

Most commonly used clinical assessment tools cannot fully capture the dynamic psychological processes often hypothesized as core mechanisms of psychopathology and psychotherapy. There is therefore a gap between our theories of problems and interventions for those problems and the tools we use to understand clients. The purpose of this special issue is to connect theory about clinical dynamics to practice by focusing on methods for collecting dynamic data, statistical models for analyzing dynamic data, and conceptual schemes for implementing dynamic data in applied settings. In this introductory article, we argue for the importance of assessing dynamic processes, highlight recent advances in assessment science that enable their measurement, review challenges in using these advances in applied practice, and adumbrate the articles in this issue.

Dynamic Gaming Platform (DGP)

Science.gov (United States)

2009-04-01

GAMING PLATFORM (DGP) Lockheed Martin Corporation...YYYY) APR 09 2. REPORT TYPE Final 3. DATES COVERED (From - To) Jul 07 – Mar 09 4. TITLE AND SUBTITLE DYNAMIC GAMING PLATFORM (DGP) 5a...CMU Carnegie Mellon University DGP Dynamic Gaming Platform GA Genetic Algorithm IARPA Intelligence Advanced Research Projects Activity LM ATL Lockheed Martin Advanced Technology Laboratories PAINT ProActive INTelligence

Dynamic Global Currency Hedging

DEFF Research Database (Denmark)

Christensen, Bent Jesper; Varneskov, Rasmus T.

2016-01-01

This paper proposes a model for discrete-time hedging based on continuous-time movements in portfolio and foreign currency exchange rate returns. In particular, the vector of optimal currency exposures is shown to be given by the negative realized regression coefficients from a one......-period conditional expectation of the intra-period quadratic covariation matrix for portfolio and foreign exchange rate returns. These are labelled the realized currency betas. The model, hence, facilitates dynamic hedging strategies that depend exclusively on the dynamic evolution of the ex-post quadratic...... covariation matrix. These hedging strategies are suggested implemented using modern, yet simple, non-parametric techniques to accurately measure and dynamically model historical quadratic covariation matrices. The empirical results from an extensive hedging exercise for equity investments illustrate...

Stochastic Switching Dynamics

DEFF Research Database (Denmark)

Simonsen, Maria

This thesis treats stochastic systems with switching dynamics. Models with these characteristics are studied from several perspectives. Initially in a simple framework given in the form of stochastic differential equations and, later, in an extended form which fits into the framework of sliding...... mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

Principles of dynamics

CERN Document Server

Hill, Rodney

2013-01-01

Principles of Dynamics presents classical dynamics primarily as an exemplar of scientific theory and method. This book is divided into three major parts concerned with gravitational theory of planetary systems; general principles of the foundations of mechanics; and general motion of a rigid body. Some of the specific topics covered are Keplerian Laws of Planetary Motion; gravitational potential and potential energy; and fields of axisymmetric bodies. The principles of work and energy, fictitious body-forces, and inertial mass are also looked into. Other specific topics examined are kinematics

Brownian dynamics simulations of sequence-dependent duplex denaturation in dynamically superhelical DNA

Science.gov (United States)

Mielke, Steven P.; Grønbech-Jensen, Niels; Krishnan, V. V.; Fink, William H.; Benham, Craig J.

2005-09-01

The topological state of DNA in vivo is dynamically regulated by a number of processes that involve interactions with bound proteins. In one such process, the tracking of RNA polymerase along the double helix during transcription, restriction of rotational motion of the polymerase and associated structures, generates waves of overtwist downstream and undertwist upstream from the site of transcription. The resulting superhelical stress is often sufficient to drive double-stranded DNA into a denatured state at locations such as promoters and origins of replication, where sequence-specific duplex opening is a prerequisite for biological function. In this way, transcription and other events that actively supercoil the DNA provide a mechanism for dynamically coupling genetic activity with regulatory and other cellular processes. Although computer modeling has provided insight into the equilibrium dynamics of DNA supercoiling, to date no model has appeared for simulating sequence-dependent DNA strand separation under the nonequilibrium conditions imposed by the dynamic introduction of torsional stress. Here, we introduce such a model and present results from an initial set of computer simulations in which the sequences of dynamically superhelical, 147 base pair DNA circles were systematically altered in order to probe the accuracy with which the model can predict location, extent, and time of stress-induced duplex denaturation. The results agree both with well-tested statistical mechanical calculations and with available experimental information. Additionally, we find that sites susceptible to denaturation show a propensity for localizing to supercoil apices, suggesting that base sequence determines locations of strand separation not only through the energetics of interstrand interactions, but also by influencing the geometry of supercoiling.

Nonlinear dynamics new directions models and applications

CERN Document Server

Ugalde, Edgardo

2015-01-01

This book, along with its companion volume, Nonlinear Dynamics New Directions: Theoretical Aspects, covers topics ranging from fractal analysis to very specific applications of the theory of dynamical systems to biology. This second volume contains mostly new applications of the theory of dynamical systems to both engineering and biology. The first volume is devoted to fundamental aspects and includes a number of important new contributions as well as some review articles that emphasize new development prospects. The topics addressed in the two volumes include a rigorous treatment of fluctuations in dynamical systems, topics in fractal analysis, studies of the transient dynamics in biological networks, synchronization in lasers, and control of chaotic systems, among others. This book also: ·         Develops applications of nonlinear dynamics on a diversity of topics such as patterns of synchrony in neuronal networks, laser synchronization, control of chaotic systems, and the study of transient dynam...

Potential vorticity dynamics for global scale circulations

International Nuclear Information System (INIS)

Lu, C.; Schubert, W.

1994-01-01

One of the most notable advances in extratropical dynamics this decade has been the understanding of large-scale atmospheric and oceanic processes by using potential vorticity dynamics, the so called open-quotes IPV thinking.close quotes This analysis method has also been successfully extended to some tropical atmospheric circulation systems such as hurricanes and the Hadley circulation. The fundamental idea behind such a dynamic system rests with the fact that PV is a tracer-like quantity since it is conserved (in the absence of friction and diabatic heating) following a fluid particle and carries both significant dynamic and thermodynamic information regarding fluid motion. Thus, the prediction and inversion of PV form the most succinct dynamic view of atmospheric and oceanic motions. Furthermore, PV dynamics provides access to many insightful dynamic analyses such as: Propagation of Rossby waves, barotropic and baroclinic instabilities for shear flows, and wave-mean flow interactions. All these features make IPV analysis a very attractive tool for studying geophysical fluid systems

Quantum dynamics in open quantum-classical systems.

Science.gov (United States)

Kapral, Raymond

2015-02-25

Often quantum systems are not isolated and interactions with their environments must be taken into account. In such open quantum systems these environmental interactions can lead to decoherence and dissipation, which have a marked influence on the properties of the quantum system. In many instances the environment is well-approximated by classical mechanics, so that one is led to consider the dynamics of open quantum-classical systems. Since a full quantum dynamical description of large many-body systems is not currently feasible, mixed quantum-classical methods can provide accurate and computationally tractable ways to follow the dynamics of both the system and its environment. This review focuses on quantum-classical Liouville dynamics, one of several quantum-classical descriptions, and discusses the problems that arise when one attempts to combine quantum and classical mechanics, coherence and decoherence in quantum-classical systems, nonadiabatic dynamics, surface-hopping and mean-field theories and their relation to quantum-classical Liouville dynamics, as well as methods for simulating the dynamics.

Dynamic jump intensities and risk premiums

DEFF Research Database (Denmark)

Christoffersen, Peter; Ornthanalai, Chayawat; Jacobs, Kris

2012-01-01

We build a new class of discrete-time models that are relatively easy to estimate using returns and/or options. The distribution of returns is driven by two factors: dynamic volatility and dynamic jump intensity. Each factor has its own risk premium. The models significantly outperform standard...... models without jumps when estimated on S&P500 returns. We find very strong support for time-varying jump intensities. Compared to the risk premium on dynamic volatility, the risk premium on the dynamic jump intensity has a much larger impact on option prices. We confirm these findings using joint...

Microsoft Dynamics NAV 2009 Professional Reporting

CERN Document Server

Renders, Steven

2011-01-01

This book doesn't assume any prior experience with Dynamics NAV reporting. It is designed as an easy to follow guide, where each chapter builds upon the previous one, but can also be read completely separately. Basically this book is for everyone who is using Microsoft Dynamics NAV or has an interest on the reporting capabilities of NAV 2009. The book does not have major prerequisites, although it is mainly focused on Dynamics NAV 2009, RDLC and Business Intelligence. Whether you are a Dynamics NAV consultant, developer, customer, project manager, or just interested in the reporting capabiliti

Ensemble simulations with discrete classical dynamics

DEFF Research Database (Denmark)

Toxværd, Søren

2013-01-01

For discrete classical Molecular dynamics (MD) obtained by the "Verlet" algorithm (VA) with the time increment $h$ there exist a shadow Hamiltonian $\\tilde{H}$ with energy $\\tilde{E}(h)$, for which the discrete particle positions lie on the analytic trajectories for $\\tilde{H}$. $\\tilde......{E}(h)$ is employed to determine the relation with the corresponding energy, $E$ for the analytic dynamics with $h=0$ and the zero-order estimate $E_0(h)$ of the energy for discrete dynamics, appearing in the literature for MD with VA. We derive a corresponding time reversible VA algorithm for canonical dynamics...

Hamiltonian dynamics for complex food webs

Science.gov (United States)

Kozlov, Vladimir; Vakulenko, Sergey; Wennergren, Uno

2016-03-01

We investigate stability and dynamics of large ecological networks by introducing classical methods of dynamical system theory from physics, including Hamiltonian and averaging methods. Our analysis exploits the topological structure of the network, namely the existence of strongly connected nodes (hubs) in the networks. We reveal new relations between topology, interaction structure, and network dynamics. We describe mechanisms of catastrophic phenomena leading to sharp changes of dynamics and hence completely altering the ecosystem. We also show how these phenomena depend on the structure of interaction between species. We can conclude that a Hamiltonian structure of biological interactions leads to stability and large biodiversity.

Multibody system dynamics, robotics and control

CERN Document Server

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.

The Hitchhiker’s Guide to Adaptive Dynamics

Directory of Open Access Journals (Sweden)

Jacob Johansson

2013-06-01

Full Text Available Adaptive dynamics is a mathematical framework for studying evolution. It extends evolutionary game theory to account for more realistic ecological dynamics and it can incorporate both frequency- and density-dependent selection. This is a practical guide to adaptive dynamics that aims to illustrate how the methodology can be applied to the study of specific systems. The theory is presented in detail for a single, monomorphic, asexually reproducing population. We explain the necessary terminology to understand the basic arguments in models based on adaptive dynamics, including invasion fitness, the selection gradient, pairwise invasibility plots (PIP, evolutionarily singular strategies, and the canonical equation. The presentation is supported with a worked-out example of evolution of arrival times in migratory birds. We show how the adaptive dynamics methodology can be extended to study evolution in polymorphic populations using trait evolution plots (TEPs. We give an overview of literature that generalises adaptive dynamics techniques to other scenarios, such as sexual, diploid populations, and spatially-structured populations. We conclude by discussing how adaptive dynamics relates to evolutionary game theory and how adaptive-dynamics techniques can be used in speciation research.

Dynamic Flaps Electronic Scan Antenna

National Research Council Canada - National Science Library

Gonzalez, Daniel

2000-01-01

A dynamic FLAPS(TM) electronic scan antenna was the focus of this research. The novelty S of this SBIR resides in the use of plasma as the main component of this dynamic X-Band phased S array antenna...

Entropy of dynamical social networks

Science.gov (United States)

Zhao, Kun; Karsai, Marton; Bianconi, Ginestra

2012-02-01

Dynamical social networks are evolving rapidly and are highly adaptive. Characterizing the information encoded in social networks is essential to gain insight into the structure, evolution, adaptability and dynamics. Recently entropy measures have been used to quantify the information in email correspondence, static networks and mobility patterns. Nevertheless, we still lack methods to quantify the information encoded in time-varying dynamical social networks. In this talk we present a model to quantify the entropy of dynamical social networks and use this model to analyze the data of phone-call communication. We show evidence that the entropy of the phone-call interaction network changes according to circadian rhythms. Moreover we show that social networks are extremely adaptive and are modified by the use of technologies such as mobile phone communication. Indeed the statistics of duration of phone-call is described by a Weibull distribution and is significantly different from the distribution of duration of face-to-face interactions in a conference. Finally we investigate how much the entropy of dynamical social networks changes in realistic models of phone-call or face-to face interactions characterizing in this way different type human social behavior.

Multiscale simulations of patchy particle systems combining Molecular Dynamics, Path Sampling and Green's Function Reaction Dynamics

Science.gov (United States)

Bolhuis, Peter

Important reaction-diffusion processes, such as biochemical networks in living cells, or self-assembling soft matter, span many orders in length and time scales. In these systems, the reactants' spatial dynamics at mesoscopic length and time scales of microns and seconds is coupled to the reactions between the molecules at microscopic length and time scales of nanometers and milliseconds. This wide range of length and time scales makes these systems notoriously difficult to simulate. While mean-field rate equations cannot describe such processes, the mesoscopic Green's Function Reaction Dynamics (GFRD) method enables efficient simulation at the particle level provided the microscopic dynamics can be integrated out. Yet, many processes exhibit non-trivial microscopic dynamics that can qualitatively change the macroscopic behavior, calling for an atomistic, microscopic description. The recently developed multiscale Molecular Dynamics Green's Function Reaction Dynamics (MD-GFRD) approach combines GFRD for simulating the system at the mesocopic scale where particles are far apart, with microscopic Molecular (or Brownian) Dynamics, for simulating the system at the microscopic scale where reactants are in close proximity. The association and dissociation of particles are treated with rare event path sampling techniques. I will illustrate the efficiency of this method for patchy particle systems. Replacing the microscopic regime with a Markov State Model avoids the microscopic regime completely. The MSM is then pre-computed using advanced path-sampling techniques such as multistate transition interface sampling. I illustrate this approach on patchy particle systems that show multiple modes of binding. MD-GFRD is generic, and can be used to efficiently simulate reaction-diffusion systems at the particle level, including the orientational dynamics, opening up the possibility for large-scale simulations of e.g. protein signaling networks.

Decoherence recuperating fast environmental dynamics

International Nuclear Information System (INIS)

Cetinbas, Murat

2010-01-01

We examine the exact internal decoherence dynamics of a qubit in an isolated Josephson charge-qubit quantum computer in the presence of one- and two-body static internal imperfections. By help of open system dynamics quantifiers, i.e. purity, fidelity, covariance and Loschmidt echo, we distinguish between non-unitary and unitary components of internal decoherence dynamics and show that the non-unitary component consists of two processes: system-environment entanglement and incoherence. Our results indicate that the incoherence process is the major source of internal decoherence rather than system-environment entanglement. We find that strong one-body intra-environmental interactions, which generate fast environmental dynamics, result in a rapid suppression of decoherence induced by both system-environment entanglement and incoherence processes. We explain the mechanisms of suppression of decoherence for these two processes and discuss our results.

Stochastic dynamics of dengue epidemics.

Science.gov (United States)

de Souza, David R; Tomé, Tânia; Pinho, Suani T R; Barreto, Florisneide R; de Oliveira, Mário J

2013-01-01

We use a stochastic Markovian dynamics approach to describe the spreading of vector-transmitted diseases, such as dengue, and the threshold of the disease. The coexistence space is composed of two structures representing the human and mosquito populations. The human population follows a susceptible-infected-recovered (SIR) type dynamics and the mosquito population follows a susceptible-infected-susceptible (SIS) type dynamics. The human infection is caused by infected mosquitoes and vice versa, so that the SIS and SIR dynamics are interconnected. We develop a truncation scheme to solve the evolution equations from which we get the threshold of the disease and the reproductive ratio. The threshold of the disease is also obtained by performing numerical simulations. We found that for certain values of the infection rates the spreading of the disease is impossible, for any death rate of infected mosquitoes.

Teaching methods for increasing the participations of students: Innovative dynamics games Teaching methods for increasing the participations of students: Innovative dynamics games Teaching methods for increasing the participations of students: Innovative dynamics games

Directory of Open Access Journals (Sweden)

Ester Oliveras

2013-09-01

Full Text Available Purpose: This paper analyses new dynamics as teaching methodologies in the context of   the degrees adapted to the EHEA. The aim of this study is double: to assess whether there is greater involvement in seminars with these new dynamics and to test if learning also experienced changes. Design/methodology/approach: To experiment with the introduction of innovative dynamic games in an introductory course in accounting.  These new dynamics are applied during the academic year 2010-11 in the UPF. The design, implementation and evaluation of the methodology devised have followed three stages: 1 Game Design and adequate dynamic; 2 To test the games; 2 Implementation during the course. Findings: The results show that students value positively those dynamics improving their learning and creating greater involvement. Research limitations/implications: There are some contradictory results regarding the knowledge gained by the students. Another area to be explored relates to the skills that the teacher must have in order to manage this type of dynamics. Originality/value: In an introductory level of the Financial Accounting course the most common dynamics is solving exercises. Due to the nature of matter, these are closed so they not provoke discussion among students. However, you can use activities that allow greater participation, especially through dynamics or games. This paper shows that.Purpose: This paper analyses new dynamics as teaching methodologies in the context of   the degrees adapted to the EHEA. The aim of this study is double: to assess whether there is greater involvement in seminars with these new dynamics and to test if learning also experienced changes.Design/methodology/approach: To experiment with the introduction of innovative dynamic games in an introductory course in accounting.  These new dynamics are applied during the academic year 2010-11 in the UPF. The design, implementation and evaluation of the methodology devised

Light-Activated Gigahertz Ferroelectric Domain Dynamics

Science.gov (United States)

Akamatsu, Hirofumi; Yuan, Yakun; Stoica, Vladimir A.; Stone, Greg; Yang, Tiannan; Hong, Zijian; Lei, Shiming; Zhu, Yi; Haislmaier, Ryan C.; Freeland, John W.; Chen, Long-Qing; Wen, Haidan; Gopalan, Venkatraman

2018-03-01

Using time- and spatially resolved hard x-ray diffraction microscopy, the striking structural and electrical dynamics upon optical excitation of a single crystal of BaTiO3 are simultaneously captured on subnanoseconds and nanoscale within individual ferroelectric domains and across walls. A large emergent photoinduced electric field of up to 20 ×106 V /m is discovered in a surface layer of the crystal, which then drives polarization and lattice dynamics that are dramatically distinct in a surface layer versus bulk regions. A dynamical phase-field modeling method is developed that reveals the microscopic origin of these dynamics, leading to gigahertz polarization and elastic waves traveling in the crystal with sonic speeds and spatially varying frequencies. The advances in spatiotemporal imaging and dynamical modeling tools open up opportunities for disentangling ultrafast processes in complex mesoscale structures such as ferroelectric domains.

Value dynamics and infrastructure reform

DEFF Research Database (Denmark)

Beck Jørgensen, Torben

2009-01-01

varying decision making contexts bear on the role of values and the handling of values. A number of theoretical explanations of value change are presented, from teleological explanations to pendulum dynamics and life cycle theories. The paper concludes with suggestions on how to deal with normative......This paper identifies the aspects of value dynamics in each of the previous papers: how the choice of institutional arrangements give primacy to some values and others not; the law and the market as separate dynamic forces; the different time horizons involved when studying value changes; and how...

Management of complex dynamical systems

Science.gov (United States)

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.

Dynamics of Oxidation of Aluminum Nanoclusters using Variable Charge Molecular-Dynamics Simulations on Parallel Computers

Science.gov (United States)

Campbell, Timothy; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Ogata, Shuji; Rodgers, Stephen

1999-06-01

Oxidation of aluminum nanoclusters is investigated with a parallel molecular-dynamics approach based on dynamic charge transfer among atoms. Structural and dynamic correlations reveal that significant charge transfer gives rise to large negative pressure in the oxide which dominates the positive pressure due to steric forces. As a result, aluminum moves outward and oxygen moves towards the interior of the cluster with the aluminum diffusivity 60% higher than that of oxygen. A stable 40 Å thick amorphous oxide is formed; this is in excellent agreement with experiments.

Inferring network topology from complex dynamics

International Nuclear Information System (INIS)

Shandilya, Srinivas Gorur; Timme, Marc

2011-01-01

Inferring the network topology from dynamical observations is a fundamental problem pervading research on complex systems. Here, we present a simple, direct method for inferring the structural connection topology of a network, given an observation of one collective dynamical trajectory. The general theoretical framework is applicable to arbitrary network dynamical systems described by ordinary differential equations. No interference (external driving) is required and the type of dynamics is hardly restricted in any way. In particular, the observed dynamics may be arbitrarily complex; stationary, invariant or transient; synchronous or asynchronous and chaotic or periodic. Presupposing a knowledge of the functional form of the dynamical units and of the coupling functions between them, we present an analytical solution to the inverse problem of finding the network topology from observing a time series of state variables only. Robust reconstruction is achieved in any sufficiently long generic observation of the system. We extend our method to simultaneously reconstructing both the entire network topology and all parameters appearing linear in the system's equations of motion. Reconstruction of network topology and system parameters is viable even in the presence of external noise that distorts the original dynamics substantially. The method provides a conceptually new step towards reconstructing a variety of real-world networks, including gene and protein interaction networks and neuronal circuits.

Dynamic quantum secret sharing

International Nuclear Information System (INIS)

Jia, Heng-Yue; Wen, Qiao-Yan; Gao, Fei; Qin, Su-Juan; Guo, Fen-Zhuo

2012-01-01

In this Letter we consider quantum secret sharing (QSS) between a sender and a dynamic agent group, called dynamic quantum secret sharing (DQSS). In the DQSS, the change of the agent group is allowable during the procedure of sharing classical and quantum information. Two DQSS schemes are proposed based on a special kind of entangled state, starlike cluster states. Without redistributing all the shares, the changed agent group can reconstruct the sender's secret by their cooperation. Compared with the previous quantum secret sharing scheme, our schemes are more flexible and suitable for practical applications. -- Highlights: ► We consider quantum secret sharing between a sender and a dynamic agent group, called dynamic quantum secret sharing (DQSS). ► In the DQSS, the change of the agent group is allowable during the procedure of sharing classical and quantum information. ► Two DQSS schemes are proposed based on a special kind of entangled state, starlike cluster states. ► Without redistributing all the shares, the changed agent group can reconstruct the sender's secret by their cooperation. ► Compared with the previous quantum secret sharing scheme, our schemes are more flexible and suitable for practical applications.

A dynamic discretization method for reliability inference in Dynamic Bayesian Networks

International Nuclear Information System (INIS)

Zhu, Jiandao; Collette, Matthew

2015-01-01

The material and modeling parameters that drive structural reliability analysis for marine structures are subject to a significant uncertainty. This is especially true when time-dependent degradation mechanisms such as structural fatigue cracking are considered. Through inspection and monitoring, information such as crack location and size can be obtained to improve these parameters and the corresponding reliability estimates. Dynamic Bayesian Networks (DBNs) are a powerful and flexible tool to model dynamic system behavior and update reliability and uncertainty analysis with life cycle data for problems such as fatigue cracking. However, a central challenge in using DBNs is the need to discretize certain types of continuous random variables to perform network inference while still accurately tracking low-probability failure events. Most existing discretization methods focus on getting the overall shape of the distribution correct, with less emphasis on the tail region. Therefore, a novel scheme is presented specifically to estimate the likelihood of low-probability failure events. The scheme is an iterative algorithm which dynamically partitions the discretization intervals at each iteration. Through applications to two stochastic crack-growth example problems, the algorithm is shown to be robust and accurate. Comparisons are presented between the proposed approach and existing methods for the discretization problem. - Highlights: • A dynamic discretization method is developed for low-probability events in DBNs. • The method is compared to existing approaches on two crack growth problems. • The method is shown to improve on existing methods for low-probability events

Emotional effects of dynamic textures

NARCIS (Netherlands)

Toet, A.; Henselmans, M.; Lucassen, M.P.; Gevers, T.

2011-01-01

This study explores the effects of various spatiotemporal dynamic texture characteristics on human emotions. The emotional experience of auditory (eg, music) and haptic repetitive patterns has been studied extensively. In contrast, the emotional experience of visual dynamic textures is still largely

HVAC-DYNAMIC; A training simulator for dynamic analysis of HVAC plants

Energy Technology Data Exchange (ETDEWEB)

Heintz, M; Novakovic, V [SINTEF Division of Applied Thermodynamic, HVAC Group, Trondheim (Norway); Oegaard, O [SINTEF Division of Automatic Control, Trondheim (Norway); Brustad, G [Computer Aided Modelling, CAMO A/S, Trondheim (Norway)

1989-01-01

HVAC-DYNAMIC is a software tool for the dynamic simulation of Heating, Ventilation and Air Conditioning (HVAC) plants. The program is designed to be used by HVAC engineers during design or troubleshooting of plants and by plant operators in their training. The program is based on a set of the most-used HVAC plant configurations and requires only a minimum of knowledge in numeric methods and programming. A brief presentation of the program structure and examples showing some of the application of the program are given. 4 figs., 4 refs.

HVAC-DYNAMIC: a training simulator for dynamic analysis of HVAC plants

Directory of Open Access Journals (Sweden)

Morten Heintz

1989-07-01

Full Text Available HVAC-DYNAMIC is a software tool for the dynamic simulation of Heating, Ventilation and Air Conditioning (HVAC plants. The program is designed to be used by HVAC engineers during design or troubleshooting of plants and by plant operators in their training. The program is based on a set of the most-used HVAC plant configurations and requires only a minimum of knowledge in numeric methods and programming. A brief presentation of the program structure and examples showing some of the application of the program are given.

Channeling and dynamic chaos

Energy Technology Data Exchange (ETDEWEB)

Bolotin, IU L; Gonchar, V IU; Truten, V I; Shulga, N F

1986-01-01

It is shown that axial channeling of relativistic electrons can give rise to the effect of dynamic chaos which involves essentially chaotic motion of a particle in the channel. The conditions leading to the effect of dynamic chaos and the manifestations of this effect in physical processes associated with the passage of particles through a crystal are examined using a silicon crystal as an example. 7 references.

The effect of host relaxation and dynamics on guest molecule dynamics in H2/tetrahydrofuranhydrate.

Science.gov (United States)

Peterson, Vanessa K; Shoko, Elvis; Kearley, Gordon J

2011-01-01

We use ab initio molecular dynamics simulations to obtain classically the effects of H2O cage motions on the potential-energy surface (PES) of encapsulated H2 in the H2/tetrahydrofuran-hydrate system. The significant differences between the PES for the H2 in rigid and flexible cages that we find will influence calculation of the quantum dynamics of the H2. Part of these differences arises from the relaxation of the H2O cage around the classical H2, with a second part arising from the coupling of both translational and rotational motions of H2 with the H20 cage. We find that isotopic substitution of 2H for 1H of the H2O cage affects the coupling, which has implications for experiments that require the use of 2H2O, including inelastic neutron scattering that uses 2H2O cages in order to focus on the H2 guest dynamics. Overall, this work emphasizes the importance of taking into account cage dynamics in any approach used to understand the dynamics of H2 guests in porous framework materials.

Dynamics and Control of a Maglev Vehicle

Directory of Open Access Journals (Sweden)

Won ko

2006-06-01

Full Text Available In this paper, dynamics of a Maglev vehicle was analyzed and controls utilizing an optimized damping and an LQR algorithms were designed to stabilize the vehicle. The dynamics of magnetically levitated and propelled Maglev vehicle are complex and inherently unstable. Moreover, 6-DOF system dynamics is highly nonlinear and coupled. The proposed control schemes provide the dynamic stability and controllability, which computer simulations confirmed the effectiveness.

Dynamics of chaotic strings

International Nuclear Information System (INIS)

Schaefer, Mirko

2011-01-01

The main topic of this thesis is the investigation of dynamical properties of coupled Tchebycheff map networks. The results give insights into the chaotic string model and its network generalization from a dynamical point of view. As a first approach, discrete symmetry transformations of the model are studied. These transformations are formulated in a general way in order to be also applicable to similar dynamics on bipartite network structures. The dynamics is studied numerically via Lyapunov measures, spatial correlations, and ergodic properties. It is shown that the zeros of the interaction energy are distinguished only with respect to this specific observable, but not by a more general dynamical principle. The original chaotic string model is defined on a one-dimensional lattice (ring-network) as the underlying network topology. This thesis studies a modification of the model based on the introduction of tunable disorder. The effects of inhomogeneous coupling weights as well as small-world perturbations of the ring-network structure on the interaction energy are discussed. Synchronization properties of the chaotic string model and its network generalization are studied in later chapters of this thesis. The analysis is based on the master stability formalism, which relates the stability of the synchronized state to the spectral properties of the network. Apart from complete synchronization, where the dynamics at all nodes of the network coincide, also two-cluster synchronization on bipartite networks is studied. For both types of synchronization it is shown that depending on the type of coupling the synchronized dynamics can display chaotic as well as periodic or quasi-periodic behaviour. The semi-analytical calculations reveal that the respective synchronized states are often stable for a wide range of coupling values even for the ring-network, although the respective basins of attraction may inhabit only a small fraction of the phase space. To provide

Non equilibrium effects in nuclear dynamics

Energy Technology Data Exchange (ETDEWEB)

Papa, M.; Arena, N.; Cardella, G.; Lanzano, G.; Filippo, E. de; Lanzalone, G.; Pagano, A.; Pirrone, S.; Politi, G. [Catania Univ., INFN Catania and Dipartimento di Fisica e Astronomia (Italy); Amorini, F.; Anzalone, A.; Bonasera, A.; Cavallaro, S.; Di Pietro, A.; Figuera, P.; Giustolisi, F.; Iacono Manno, M.; La Guidara, E.; Maiolino, C.; Porto, F.; Rizzo, F.; Sperduto, M.L. [Catania Univ., INFN-LNS and Dipartimento di Fisica e Astronomia (Italy); Auditore, L.; Trifiro, A.; Trimarchi, M. [Messina Univ., INFN and Dipartimento di Fisica (Italy)

2003-07-01

A Constraint Molecular Dynamics (CoMD) approach is used to study dynamical effects related to both the average dynamics and the fluctuations around it. Data obtained in the REVERSE and in TRASMARAD experiments were compared with the theoretical simulations. The concept of temperature, as derived from a fully dynamical description of the GDR (giant dipole resonance) mode, is also discussed. In this contribution we have discussed the comparison between the CoMD model and two classes of phenomena, induced by heavy ion collisions. The first one is related to the IMF (intermediate mass fragment) production in semi-peripheral collisions for the {sup 124}Sn + {sup 64}Ni system at 35 MeV/nucleon. The comparison put in evidence clear preequilibrium effects in the fragment production mechanism which are essentially related to the behavior of the average dynamics. The second one concerns the high {gamma}-ray productions, due to dipolar resonant mechanisms, in the {sup 40}Ca + {sup 48}Ca system at 25 MeV/nucleon. In this case the comparisons with the model allows to put in evidence preequilibrium effects related both to the average dynamics and to the fluctuating one.

Dynamics of quantised vortices in superfluids

CERN Document Server

Sonin, Edouard B

2016-01-01

A comprehensive overview of the basic principles of vortex dynamics in superfluids, this book addresses the problems of vortex dynamics in all three superfluids available in laboratories (4He, 3He, and BEC of cold atoms) alongside discussions of the elasticity of vortices, forces on vortices, and vortex mass. Beginning with a summary of classical hydrodynamics, the book guides the reader through examinations of vortex dynamics from large scales to the microscopic scale. Topics such as vortex arrays in rotating superfluids, bound states in vortex cores and interaction of vortices with quasiparticles are discussed. The final chapter of the book considers implications of vortex dynamics to superfluid turbulence using simple scaling and symmetry arguments. Written from a unified point of view that avoids complicated mathematical approaches, this text is ideal for students and researchers working with vortex dynamics in superfluids, superconductors, magnetically ordered materials, neutron stars and cosmological mo...

Cytoskeleton dynamics: Fluctuations within the network

International Nuclear Information System (INIS)

Bursac, Predrag; Fabry, Ben; Trepat, Xavier; Lenormand, Guillaume; Butler, James P.; Wang, Ning; Fredberg, Jeffrey J.; An, Steven S.

2007-01-01

Out-of-equilibrium systems, such as the dynamics of a living cytoskeleton (CSK), are inherently noisy with fluctuations arising from the stochastic nature of the underlying biochemical and molecular events. Recently, such fluctuations within the cell were characterized by observing spontaneous nano-scale motions of an RGD-coated microbead bound to the cell surface [Bursac et al., Nat. Mater. 4 (2005) 557-561]. While these reported anomalous bead motions represent a molecular level reorganization (remodeling) of microstructures in contact with the bead, a precise nature of these cytoskeletal constituents and forces that drive their remodeling dynamics are largely unclear. Here, we focused upon spontaneous motions of an RGD-coated bead and, in particular, assessed to what extent these motions are attributable to (i) bulk cell movement (cell crawling), (ii) dynamics of focal adhesions, (iii) dynamics of lipid membrane, and/or (iv) dynamics of the underlying actin CSK driven by myosin motors

Numerical methods in dynamic fracture mechanics

International Nuclear Information System (INIS)

Beskos, D.E.

1987-01-01

A review of numerical methods for the solution of dynamic problems of fracture mechanics is presented. Finite difference, finite element and boundary element methods as applied to linear elastic or viscoelastic and non-linear elastoplastic or elastoviscoplastic dynamic fracture mechanics problems are described and critically evaluated. Both cases of stationary cracks and rapidly propagating cracks of simple I, II, III or mixed modes are considered. Harmonically varying with time or general transient dynamic disturbances in the form of external loading or incident waves are taken into account. Determination of the dynamic stress intensity factor for stationary cracks or moving cracks with known velocity history as well as determination of the crack-tip propagation history for given dynamic fracture toughness versus crack velocity relation are described and illustrated by means of certain representative examples. Finally, a brief assessment of the present state of knowledge is made and research needs are identified

Vortex dynamics in inhomogeneous plasmas

DEFF Research Database (Denmark)

Naulin, V.; Juul Rasmussen, J.

1999-01-01

The dynamics of vortical structures in magnetized plasmas with nonuniform density is investigated numerically. In particular the dynamics of monopolar vortices is considered and the results are discussed in terms of the conservation of potential vorticity. It is found that individual vortex...

Parameterizing Coefficients of a POD-Based Dynamical System

Science.gov (United States)

Kalb, Virginia L.

2010-01-01

A method of parameterizing the coefficients of a dynamical system based of a proper orthogonal decomposition (POD) representing the flow dynamics of a viscous fluid has been introduced. (A brief description of POD is presented in the immediately preceding article.) The present parameterization method is intended to enable construction of the dynamical system to accurately represent the temporal evolution of the flow dynamics over a range of Reynolds numbers. The need for this or a similar method arises as follows: A procedure that includes direct numerical simulation followed by POD, followed by Galerkin projection to a dynamical system has been proven to enable representation of flow dynamics by a low-dimensional model at the Reynolds number of the simulation. However, a more difficult task is to obtain models that are valid over a range of Reynolds numbers. Extrapolation of low-dimensional models by use of straightforward Reynolds-number-based parameter continuation has proven to be inadequate for successful prediction of flows. A key part of the problem of constructing a dynamical system to accurately represent the temporal evolution of the flow dynamics over a range of Reynolds numbers is the problem of understanding and providing for the variation of the coefficients of the dynamical system with the Reynolds number. Prior methods do not enable capture of temporal dynamics over ranges of Reynolds numbers in low-dimensional models, and are not even satisfactory when large numbers of modes are used. The basic idea of the present method is to solve the problem through a suitable parameterization of the coefficients of the dynamical system. The parameterization computations involve utilization of the transfer of kinetic energy between modes as a function of Reynolds number. The thus-parameterized dynamical system accurately predicts the flow dynamics and is applicable to a range of flow problems in the dynamical regime around the Hopf bifurcation. Parameter

Ion-Molecule Reaction Dynamics.

Science.gov (United States)

Meyer, Jennifer; Wester, Roland

2017-05-05

We review the recent advances in the investigation of the dynamics of ion-molecule reactions. During the past decade, the combination of single-collision experiments in crossed ion and neutral beams with the velocity map ion imaging detection technique has enabled a wealth of studies on ion-molecule reactions. These methods, in combination with chemical dynamics simulations, have uncovered new and unexpected reaction mechanisms, such as the roundabout mechanism and the subtle influence of the leaving group in anion-molecule nucleophilic substitution reactions. For this important class of reactions, as well as for many fundamental cation-molecule reactions, the information obtained with crossed-beam imaging is discussed. The first steps toward understanding micro-solvation of ion-molecule reaction dynamics are presented. We conclude with the presentation of several interesting directions for future research.

Vorticity and vortex dynamics

CERN Document Server

Wu, Jie-Zhi; Zhou, M-D

2006-01-01

The importance of vorticity and vortex dynamics has now been well rec- nized at both fundamental and applied levels of ?uid dynamics, as already anticipatedbyTruesdellhalfcenturyagowhenhewrotethe?rstmonograph onthesubject, The Kinematics of Vorticity(1954);andasalsoevidencedby the appearance of several books on this ?eld in 1990s. The present book is characterizedbythefollowingfeatures: 1. A basic physical guide throughout the book. The material is directed by a basic observation on the splitting and coupling of two fundamental processes in ?uid motion, i.e., shearing (unique to ?uid) and compre- ing/expanding.Thevorticityplaysakeyroleintheformer,andavortex isnothingbuta?uidbodywithhighconcentrationofvorticitycompared to its surrounding ?uid. Thus, the vorticity and vortex dynamics is - cordinglyde?nedasthetheoryofshearingprocessanditscouplingwith compressing/expandingprocess. 2. A description of the vortex evolution following its entire life.Thisbegins from the generation of vorticity to the formation of thi...

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...... reconstructed the Butschli system and observed its life span under a light microscope, observing chemical patterns and droplet behaviors in nearly three hundred replicate experiments. Self-organizing patterns were observed, and during this dynamic, embodied phase the droplets provided a means of introducing...... temporal and spatial order in the system with the potential for chemical programmability. The authors propose that the discrete formation of dynamic droplets, characterized by their lifelike behavior patterns, during a variable window of time (from 30 s to 30 min after the addition of alkaline water...

Coherent dynamics in semiconductors

DEFF Research Database (Denmark)

Hvam, Jørn Märcher

1998-01-01

enhanced in quantum confined lower-dimensional systems, where exciton and biexciton effects dominate the spectra even at room temperature. The coherent dynamics of excitons are at modest densities well described by the optical Bloch equations and a number of the dynamical effects known from atomic......Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

Dynamical System Approaches to Combinatorial Optimization

DEFF Research Database (Denmark)

Starke, Jens

2013-01-01

of large times as an asymptotically stable point of the dynamics. The obtained solutions are often not globally optimal but good approximations of it. Dynamical system and neural network approaches are appropriate methods for distributed and parallel processing. Because of the parallelization......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...... thereof can be used as models for many industrial problems like manufacturing planning and optimization of flexible manufacturing systems. This is illustrated for an example in distributed robotic systems....

Dynamics of partial differential equations

CERN Document Server

Wayne, C Eugene

2015-01-01

This book contains two review articles on the dynamics of partial differential equations that deal with closely related topics but can be read independently. Wayne reviews recent results on the global dynamics of the two-dimensional Navier-Stokes equations. This system exhibits stable vortex solutions: the topic of Wayne's contribution is how solutions that start from arbitrary initial conditions evolve towards stable vortices. Weinstein considers the dynamics of localized states in nonlinear Schrodinger and Gross-Pitaevskii equations that describe many optical and quantum systems. In this contribution, Weinstein reviews recent bifurcations results of solitary waves, their linear and nonlinear stability properties, and results about radiation damping where waves lose energy through radiation.   The articles, written independently, are combined into one volume to showcase the tools of dynamical systems theory at work in explaining qualitative phenomena associated with two classes of partial differential equ...

dynamic performance of research reactors

International Nuclear Information System (INIS)

Abo elnor, A.G.M.

2007-01-01

this work studies the dynamic performance of material testing reactor (MTR), where the dynamic performance of any reactor reflects its safety behavior and it should enhance its intrinsic characteristics s ystem corrects itself internally without introducing external corrective action . the present work analyzes and studies the dynamic performance of mtr through the transfer function. the servo system parameters can be changed to fit the system demand. the servo system is an excellent approximation to some of the practical servo system currently use in reactor control system, and a quadratic form of this sort should closely approximate the behavior of almost any type of physical equipment which might be chosen to drive a control rod. proposed changes in servo system parameters could enhance the dynamic performance of the system , but the suitable parameters can be evaluated by using the automatic reactor power control system model

Dynamic large eddy simulation: Stability via realizability

Science.gov (United States)

Mokhtarpoor, Reza; Heinz, Stefan

2017-10-01

The concept of dynamic large eddy simulation (LES) is highly attractive: such methods can dynamically adjust to changing flow conditions, which is known to be highly beneficial. For example, this avoids the use of empirical, case dependent approximations (like damping functions). Ideally, dynamic LES should be local in physical space (without involving artificial clipping parameters), and it should be stable for a wide range of simulation time steps, Reynolds numbers, and numerical schemes. These properties are not trivial, but dynamic LES suffers from such problems over decades. We address these questions by performing dynamic LES of periodic hill flow including separation at a high Reynolds number Re = 37 000. For the case considered, the main result of our studies is that it is possible to design LES that has the desired properties. It requires physical consistency: a PDF-realizable and stress-realizable LES model, which requires the inclusion of the turbulent kinetic energy in the LES calculation. LES models that do not honor such physical consistency can become unstable. We do not find support for the previous assumption that long-term correlations of negative dynamic model parameters are responsible for instability. Instead, we concluded that instability is caused by the stable spatial organization of significant unphysical states, which are represented by wall-type gradient streaks of the standard deviation of the dynamic model parameter. The applicability of our realizability stabilization to other dynamic models (including the dynamic Smagorinsky model) is discussed.

Dynamic contraction behaviour of pneumatic artificial muscle

Science.gov (United States)

Doumit, Marc D.; Pardoel, Scott

2017-07-01

The development of a dynamic model for the Pneumatic Artificial Muscle (PAM) is an imperative undertaking for understanding and analyzing the behaviour of the PAM as a function of time. This paper proposes a Newtonian based dynamic PAM model that includes the modeling of the muscle geometry, force, inertia, fluid dynamic, static and dynamic friction, heat transfer and valve flow while ignoring the effect of bladder elasticity. This modeling contribution allows the designer to predict, analyze and optimize PAM performance prior to its development. Thus advancing successful implementations of PAM based powered exoskeletons and medical systems. To date, most muscle dynamic properties are determined experimentally, furthermore, no analytical models that can accurately predict the muscle's dynamic behaviour are found in the literature. Most developed analytical models adequately predict the muscle force in static cases but neglect the behaviour of the system in the transient response. This could be attributed to the highly challenging task of deriving such a dynamic model given the number of system elements that need to be identified and the system's highly non-linear properties. The proposed dynamic model in this paper is successfully simulated through MATLAB programing and validated the pressure, contraction distance and muscle temperature with experimental testing that is conducted with in-house built prototype PAM's.

Unifying dynamical and structural stability of equilibria

Science.gov (United States)

Arnoldi, Jean-François; Haegeman, Bart

2016-09-01

We exhibit a fundamental relationship between measures of dynamical and structural stability of linear dynamical systems-e.g. linearized models in the vicinity of equilibria. We show that dynamical stability, quantified via the response to external perturbations (i.e. perturbation of dynamical variables), coincides with the minimal internal perturbation (i.e. perturbations of interactions between variables) able to render the system unstable. First, by reformulating a result of control theory, we explain that harmonic external perturbations reflect the spectral sensitivity of the Jacobian matrix at the equilibrium, with respect to constant changes of its coefficients. However, for this equivalence to hold, imaginary changes of the Jacobian's coefficients have to be allowed. The connection with dynamical stability is thus lost for real dynamical systems. We show that this issue can be avoided, thus recovering the fundamental link between dynamical and structural stability, by considering stochastic noise as external and internal perturbations. More precisely, we demonstrate that a linear system's response to white-noise perturbations directly reflects the intensity of internal white-noise disturbance that it can accommodate before becoming stochastically unstable.

Dynamic Optimization of UV Flash Processes

DEFF Research Database (Denmark)

Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Jørgensen, John Bagterp

2017-01-01

UV ash processes, also referred to as isoenergetic-isochoric ash processes, occur for dynamic simulation and optimization of vapor-liquid equilibrium processes. Dynamic optimization and nonlinear model predictive control of distillation columns, certain two-phase ow problems, as well as oil reser...... that the optimization solver, the compiler, and high-performance linear algebra software are all important for e_cient dynamic optimization of UV ash processes....

Dynamic Stability Experiment of Maglev Systems,

Science.gov (United States)

1995-04-01

This report summarizes the research performed on maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also... maglev system, it is important to consider this phenomenon in the development of all maglev systems. This report presents dynamic stability experiments...on maglev systems and compares their numerical simulation with predictions calculated by a nonlinear dynamic computer code. Instabilities of an

Instability of quantum equilibrium in Bohm's dynamics.

Science.gov (United States)

Colin, Samuel; Valentini, Antony

2014-11-08

We consider Bohm's second-order dynamics for arbitrary initial conditions in phase space. In principle, Bohm's dynamics allows for 'extended' non-equilibrium, with initial momenta not equal to the gradient of phase of the wave function (as well as initial positions whose distribution departs from the Born rule). We show that extended non-equilibrium does not relax in general and is in fact unstable. This is in sharp contrast with de Broglie's first-order dynamics, for which non-standard momenta are not allowed and which shows an efficient relaxation to the Born rule for positions. On this basis, we argue that, while de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In a world governed by Bohm's dynamics, there would be no reason to expect to see an effective quantum theory today (even approximately), in contradiction with observation.

On the Dynamics of the Furuta Pendulum

Directory of Open Access Journals (Sweden)

Benjamin Seth Cazzolato

2011-01-01

Full Text Available The Furuta pendulum, or rotational inverted pendulum, is a system found in many control labs. It provides a compact yet impressive platform for control demonstrations and draws the attention of the control community as a platform for the development of nonlinear control laws. Despite the popularity of the platform, there are very few papers which employ the correct dynamics and only one that derives the full system dynamics. In this paper, the full dynamics of the Furuta pendulum are derived using two methods: a Lagrangian formulation and an iterative Newton-Euler formulation. Approximations are made to the full dynamics which converge to the more commonly presented expressions. The system dynamics are then linearised using a Jacobian. To illustrate the influence the commonly neglected inertia terms have on the system dynamics, a brief example is offered.

Anomalous diffusion in a dynamical optical lattice

Science.gov (United States)

Zheng, Wei; Cooper, Nigel R.

2018-02-01

Motivated by experimental progress in strongly coupled atom-photon systems in optical cavities, we study theoretically the quantum dynamics of atoms coupled to a one-dimensional dynamical optical lattice. The dynamical lattice is chosen to have a period that is incommensurate with that of an underlying static lattice, leading to a dynamical version of the Aubry-André model which can cause localization of single-particle wave functions. We show that atomic wave packets in this dynamical lattice generically spread via anomalous diffusion, which can be tuned between superdiffusive and subdiffusive regimes. This anomalous diffusion arises from an interplay between Anderson localization and quantum fluctuations of the cavity field.

Short-term Consumer Benefits of Dynamic Pricing

OpenAIRE

Dupont, Benjamin; De Jonghe, Cedric; Kessels, Kris; Belmans, Ronnie

2011-01-01

Consumer benefits of dynamic pricing depend on a variety of factors. Consumer characteristics and climatic circumstances widely differ, which forces a regional comparison. This paper presents a general overview of demand response programs and focuses on the short-term benefits of dynamic pricing for an average Flemish residential consumer. It reaches a methodology to develop a cost reflective dynamic pricing program and to estimate short-term bill savings. Participating in a dynamic pricing p...

A MODIFIED GIFFLER AND THOMPSON ALGORITHM COMBINED WITH DYNAMIC SLACK TIME FOR SOLVING DYNAMIC SCHEDULE PROBLEMS

Directory of Open Access Journals (Sweden)

Tanti Octavia

2003-01-01

Full Text Available A Modified Giffler and Thompson algorithm combined with dynamic slack time is used to allocate machines resources in dynamic nature. It was compared with a Real Time Order Promising (RTP algorithm. The performance of modified Giffler and Thompson and RTP algorithms are measured by mean tardiness. The result shows that modified Giffler and Thompson algorithm combined with dynamic slack time provides significantly better result compared with RTP algorithm in terms of mean tardiness.

Dynamics of structures

CERN Document Server

Paultre, Patrick

2013-01-01

This book covers structural dynamics from a theoretical and algorithmic approach. It covers systems with both single and multiple degrees-of-freedom. Numerous case studies are given to provide the reader with a deeper insight into the practicalities of the area, and the solutions to these case studies are given in terms of real-time and frequency in both geometric and modal spaces. Emphasis is also given to the subject of seismic loading. The text is based on many lectures on the subject of structural dynamics given at numerous institutions and thus will be an accessible and practical aid to

Dynamical Systems for Creative Technology

NARCIS (Netherlands)

van Amerongen, J.

2010-01-01

Dynamical Systems for Creative Technology gives a concise description of the physical properties of electrical, mechanical and hydraulic systems. Emphasis is placed on modelling the dynamical properties of these systems. By using a system’s approach it is shown that a limited number of mathematical

Dynamic simulation of a reboiler

International Nuclear Information System (INIS)

Moeck, E.O.; McMorran, P.D.

1977-07-01

A hybrid-computer simulation of reboiler dynamics was prepared, comprising models of steam condensation in tubes, heat conduction, steam generation, a surge tank, steam transmission line and flow-control valve. Time and frequency responses were obtained to illustrate the dynamics of this multivariable process. (author)

Stellar dynamics and black holes

Indian Academy of Sciences (India)

Chandrasekhar's most important contribution to stellar dynamics was the concept of dynamical friction. I briefly review that work, then discuss some implications of Chandrasekhar's theory of gravitational encounters for motion in galactic nuclei. Author Affiliations. David Merritt1. Department of Physics, Rochester Institute ...

Dynamics on the Riemann Sphere

DEFF Research Database (Denmark)

Petersen, Carsten Lunde

Collection of research papers on holomorphic dynamical systems with an introduction to Bodil Branners works on the field. Contributions: John Milnor: On Lattès Maps. Carsten Lunde Petersen and Tan Lei: Branner-Hubbard motions and attracting dynamics. Artur Avila and Mikhail Lyubich: Examples...

Modelling dynamic roughness during floods

NARCIS (Netherlands)

Paarlberg, Andries; Dohmen-Janssen, Catarine M.; Hulscher, Suzanne J.M.H.; Termes, A.P.P.

2007-01-01

In this paper, we present a dynamic roughness model to predict water levels during floods. Hysteresis effects of dune development are explicitly included. It is shown that differences between the new dynamic roughness model, and models where the roughness coefficient is calibrated, are most

The Dynamical Theory of Coevolution

NARCIS (Netherlands)

Dieckmann, Ulf

1997-01-01

A unifying framework is presented for describing the phenotypic coevolutionary dynamics of a general ecological community. We start from an individual-based approach allowing for the interaction of an arbitrary number of species. The adaptive dynamics of species’ trait values are derived from the

Dynamic MR imaging of pancreatic cancer

International Nuclear Information System (INIS)

Akaki, Shiro; Kohno, Yoshihiro; Gohbara, Hideo

1994-01-01

Dynamic MRI was performed on 21 patients with pancreatic duct cell carcinoma. Turbo-FLASH or FLASH3D was performed immediately following rapid bolus injection of gadopentetate dimeglumine, and these FLASH images and conventional spin echo images were evaluated about detectability of the lesion. All images were classified into three groups of detectability of the lesion ; good, fair, and poor. On T 1 weighted image, 23% of cases were 'good' and 48% were evaluated as 'fair'. On the other hand, on dynamic MRI, 62% of cases were 'good' and 33% of cases were evaluated as 'fair'. Both T 2 weighted image and enhanced T 1 weighted image were not useful for depiction of the lesion. Direct comparison between T 1 weighted image and dynamic MRI was also done. In 55% of cases, dynamic MRI was superior to T 1 weighted image and in 40% of cases, dynamic MRI was equal to T 1 weighted image. Thus, dynamic MRI was superior to conventional spin echo images for detection of duct cell carcinoma. In 17 patients of duct cell carcinoma who underwent FLASH3D, contrast/noise ratio (CNR) was calculated before and after injection of gadopentetate dimeglumine. The absolute value of CNR became significantly larger by injection of contrast material. In nine resectable pancreatic carcinomas, two cases of INF α and two cases of medullary type were well depicted. It was concluded that dynamic MRI was useful for evaluation of pancreatic carcinoma. (author)

Dynamic properties of energy affordability measures

International Nuclear Information System (INIS)

Heindl, Peter; Schuessler, Rudolf

2015-01-01

Measures of affordability and of fuel poverty are applied in practice to assess the affordability of energy services, for example, or of water or housing. The extensive body of literature on affordability measures has little overlap with the existing literature on poverty measurement. A comprehensive assessment of the response of affordability measures as a result of changes in the distribution of income or expenditure (the dynamic properties) is missing. This paper aims to fill this gap by providing a conceptual discussion on the ‘dynamics’ of both energy affordability measures and fuel poverty measures. Several types of measures are examined in a microsimulation framework. Our results indicate that some measures exhibit odd dynamic behavior. This includes measures used in practice, such as the low income/high cost measure and the double median of expenditure share indicator. Odd dynamic behavior causes the risk of drawing false policy recommendations from the measures. Thus, an appropriate response of affordability measures to changes in relevant variables is a prerequisite for defining meaningful measures that inform about affordability or deprivation in certain domains of consumption. - Highlights: • We investigate changes in fuel poverty measures as result from changes in income and expenditure. • More generally, we investigate dynamic behavior of affordability measures using microsimulation. • We propose axioms regarding dynamic behavior of affordability measures. • Some measures which are used in practice show unintuitive dynamic behavior. • Inappropriate dynamic behavior causes a risk of false policy implications.

Qualitative methods in nuclear reactor dynamics. Issue 23

International Nuclear Information System (INIS)

Goryachenko, V.D.

1983-01-01

Applicability of qualitative methods of the theory of nonlinear oscillations including the bifurcation theory to the problems of nuclear reactor nonlinear dynamics is investigated. Basic statements of the dynamic system qualitative theory on a phase plane and the bifurcation theory of multidimensional dynamic systems are briefly outlined. The model of reactor dynamics with two reactivity temperature coefficients neglecting delayed neutrons, the model of slow process dynamics in a reactor with two reactivity temperature coefficients, the simplified model of reactor dynamics as an object with delay and the model of a reactor with linear feedback are considered. A conclusion is drawn that the usage of the above models allows one to reveal qualitative peculiarities of reactor dynamics creating conditions for more purposeful utilization of more complicated models

Relating structure and dynamics in organisation models

NARCIS (Netherlands)

Jonkers, C.M.; Treur, J.

2002-01-01

To understand how an organisational structure relates to dynamics is an interesting fundamental challenge in the area of social modelling. Specifications of organisational structure usually have a diagrammatic form that abstracts from more detailed dynamics. Dynamic properties of agent systems,

Relating structure and dynamics in organisation models

NARCIS (Netherlands)

Jonker, C.M.; Treur, J.

2003-01-01

To understand how an organisational structure relates to dynamics is an interesting fundamental challenge in the area of social modelling. Specifications of organisational structure usually have a diagrammatic form that abstracts from more detailed dynamics. Dynamic properties of agent systems, on

Dynamic CT of hepatocellular carcinoma

International Nuclear Information System (INIS)

Fujita, Nobuyuki; Shirato, Hiroki; Shinohara, Masahiro; Miyasaka, Kazuo; Morita, Yutaka; Irie, Goro

1983-01-01

We performed dynamic CT in 30 cases of hepatocellular carcinoma, and concluded as below. 1 Decting the stain in the early phase of the dynamic series, it is possible to make a diagnosis of hepatocellular carcinoma. 2 The dinamic CT is effective in a case of small hepatocellular carcinoma in which it is difficult to gain an accurate diagnosis in the routine CT study. 3 The dynamic CT is also effective in the differential diagnosis of hepatic lesions, as other hepatic lesions such as hemangioma and metastatic liver cancer show different patterns compared with hepatocellular carcinoma. (author)

Dislocation Dynamics During Plastic Deformation

CERN Document Server

Messerschmidt, Ulrich

2010-01-01

The book gives an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail. Finally, examples are described of the processes in different classes of materials, i.e. semiconductors, ceramics, metals, intermetallic materials, and quasicrystals. The processes are illustrated by many electron micrographs of dislocations under stress and by video clips taken during in situ straining experiments in a high-voltage electron microscope showing moving dislocations. Thus, the users of the book also obtain an immediate impression and understanding of dislocation dynamics.

Dynamics and causality constraints

International Nuclear Information System (INIS)

Sousa, Manoelito M. de

2001-04-01

The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)

Reconstructing time-dependent dynamics

OpenAIRE

Clemson, Philip; Lancaster, Gemma; Stefanovska, Aneta

2016-01-01

The usefulness of the information extracted from biomedical data relies heavily on the underlying theory of the methods used in its extraction. The assumptions of stationarity and autonomicity traditionally applied to dynamical systems break down when considering living systems, due to their inherent time-variability. Living systems are thermodynamically open, and thus constantly interacting with their environment. This results in highly nonlinear, time-dependent dynamics. The aim of signal a...

Dynamics of magnetospheric plasmas

International Nuclear Information System (INIS)

Horwitz, J.L.

1985-01-01

The dynamical behavior of the magnetospheric plasmas which control the electrostatic charging of spacecraft is the result of the complex interaction of a variety of production, loss, transport, and energization mechanisms in the magnetosphere. This paper is intended to provide the spacecraft engineer with a foundation in the basic morphology and controlling processes pertaining to magnetospheric plasma dynamics in the inner magnetosphere, including the synchronous orbit region. 32 references

Nonlinear analysis of dynamic signature

Science.gov (United States)

Rashidi, S.; Fallah, A.; Towhidkhah, F.

2013-12-01

Signature is a long trained motor skill resulting in well combination of segments like strokes and loops. It is a physical manifestation of complex motor processes. The problem, generally stated, is that how relative simplicity in behavior emerges from considerable complexity of perception-action system that produces behavior within an infinitely variable biomechanical and environmental context. To solve this problem, we present evidences which indicate that motor control dynamic in signing process is a chaotic process. This chaotic dynamic may explain a richer array of time series behavior in motor skill of signature. Nonlinear analysis is a powerful approach and suitable tool which seeks for characterizing dynamical systems through concepts such as fractal dimension and Lyapunov exponent. As a result, they can be analyzed in both horizontal and vertical for time series of position and velocity. We observed from the results that noninteger values for the correlation dimension indicates low dimensional deterministic dynamics. This result could be confirmed by using surrogate data tests. We have also used time series to calculate the largest Lyapunov exponent and obtain a positive value. These results constitute significant evidence that signature data are outcome of chaos in a nonlinear dynamical system of motor control.

Holocene fire dynamics in Fennoscandia

Science.gov (United States)

Clear, Jennifer; Seppa, Heikki; Kuosmanen, Niina; Molinari, Chiara; Lehsten, Veiko; Allen, Katherine; Bradshaw, Richard

2015-04-01

Prescribed burning is advocated in Fennoscandia to promote regeneration and to encourage biodiversity. This method of forest management is based on the perception that fire was much more frequent in the recent past and over a century of active fire suppression has created a boreal forest ecosystem almost free of natural fire. The absence of fire is thought to have contributed to the widespread dominance of Picea abies (Norway spruce) with the successive spruce dominated forest further reducing fire ignition potential. However, humans have altered the natural fire dynamics of Fennoscandia since the early- to mid-Holocene and disentangling the anthropogenic driven fire dynamics from the natural fire dynamics is challenging. Through palaeoecology and sedimentary charcoal deposits we are able to explore the Holocene spatial and temporal variability and changing drivers of fire and vegetation dynamics in Fennoscandia. At the local-scale, two forest hollow environments (history are compared to identify unique and mutual changes in disturbance history. Pollen derived quantitative reconstruction of vegetation at both the local- and regional-scale identifies local-scale disturbance dynamics and large-scale ecosystem response. Spatio-temporal heterogeneity and variability in biomass burning is explored throughout Fennoscandia and Denmark to identify the changing drives of fire dynamics throughout the Holocene. Palaeo-vegetation reconstructions are compared to process-based, climate driven dynamic vegetation model output to test the significance of fire frequency as a driver of vegetation composition and dynamics. Early-Holocene fire regimes in Fennoscandia are driven by natural climate variations and fuel availability. The establishment and spread of Norway spruce is driven by an increase in continentality of climate, but local natural and anthropogenic ecosystem disturbance may have aided this spread. The expansion of spruce led to a step-wise reduction in regional biomass

Early days in complex dynamics a history of complex dynamics in one variable during 1906-1942

CERN Document Server

Alexander, Daniel S; Rosa, Alessandro

2011-01-01

The theory of complex dynamics, whose roots lie in 19th-century studies of the iteration of complex function conducted by Kœnigs, Schröder, and others, flourished remarkably during the first half of the 20th century, when many of the central ideas and techniques of the subject developed. This book by Alexander, Iavernaro, and Rosa paints a robust picture of the field of complex dynamics between 1906 and 1942 through detailed discussions of the work of Fatou, Julia, Siegel, and several others. A recurrent theme of the authors' treatment is the center problem in complex dynamics. They present its complete history during this period and, in so doing, bring out analogies between complex dynamics and the study of differential equations, in particular, the problem of stability in Hamiltonian systems. Among these analogies are the use of iteration and problems involving small divisors which the authors examine in the work of Poincaré and others, linking them to complex dynamics, principally via the work of Samuel...

Dynamics of Railway Vehicles and Rail/Wheel Contact

DEFF Research Database (Denmark)

True, Hans

2007-01-01

of the most important dynamic effects on vehicle dynamic problems are described. In chapter 7 characteristic features of railway vehicle dynamics are described, and in chapter 8 recommendations are presented for the numerical handling that is necessary for the investigation of vehicle dynamic problems...

Quantum wavepacket ab initio molecular dynamics: an approach for computing dynamically averaged vibrational spectra including critical nuclear quantum effects.

Science.gov (United States)

Sumner, Isaiah; Iyengar, Srinivasan S

2007-10-18

We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically improved (by several orders of magnitude) through the utilization of wavelet-based techniques combined with the previously introduced time-dependent deterministic sampling procedure measure to achieve stable, picosecond length, quantum-classical dynamics of electrons and nuclei in clusters. The dynamical information is employed to construct a novel cumulative flux/velocity correlation function, where the wavepacket flux from the quantized particle is combined with classical nuclear velocities to obtain the vibrational density of states. The approach is demonstrated by computing the vibrational density of states of [Cl-H-Cl]-, inclusive of critical quantum nuclear effects, and our results are in good agreement with experiment. A general hierarchical procedure is also provided, based on electronic structure harmonic frequencies, classical ab initio molecular dynamics, computation of nuclear quantum-mechanical eigenstates, and employing quantum wavepacket ab initio dynamics to understand vibrational spectroscopy in hydrogen-bonded clusters that display large degrees of anharmonicities.

Dynamic Modelling Of A SCARA Robot

Science.gov (United States)

Turiel, J. Perez; Calleja, R. Grossi; Diez, V. Gutierrez

1987-10-01

This paper describes a method for modelling industrial robots that considers dynamic approach to manipulation systems motion generation, obtaining the complete dynamic model for the mechanic part of the robot and taking into account the dynamic effect of actuators acting at the joints. For a four degree of freedom SCARA robot we obtain the dynamic model for the basic (minimal) configuration, that is, the three degrees of freedom that allow us to place the robot end effector in a desired point, using the Lagrange Method to obtain the dynamic equations in matrix form. The manipulator is considered to be a set of rigid bodies inter-connected by joints in the form of simple kinematic pairs. Then, the state space model is obtained for the actuators that move the robot joints, uniting the models of the single actuators, that is, two DC permanent magnet servomotors and an electrohydraulic actuator. Finally, using a computer simulation program written in FORTRAN language, we can compute the matrices of the complete model.

Dynamic Simulations of Advanced Fuel Cycles

International Nuclear Information System (INIS)

Piet, Steven J.; Dixon, Brent W.; Jacobson, Jacob J.; Matthern, Gretchen E.; Shropshire, David E.

2011-01-01

Years of performing dynamic simulations of advanced nuclear fuel cycle options provide insights into how they could work and how one might transition from the current once-through fuel cycle. This paper summarizes those insights from the context of the 2005 objectives and goals of the U.S. Advanced Fuel Cycle Initiative (AFCI). Our intent is not to compare options, assess options versus those objectives and goals, nor recommend changes to those objectives and goals. Rather, we organize what we have learned from dynamic simulations in the context of the AFCI objectives for waste management, proliferation resistance, uranium utilization, and economics. Thus, we do not merely describe 'lessons learned' from dynamic simulations but attempt to answer the 'so what' question by using this context. The analyses have been performed using the Verifiable Fuel Cycle Simulation of Nuclear Fuel Cycle Dynamics (VISION). We observe that the 2005 objectives and goals do not address many of the inherently dynamic discriminators among advanced fuel cycle options and transitions thereof.

Dynamism or Disorder at High Pressures?

Science.gov (United States)

Angel, R. J.; Bismayer, U.; Marshall, W. G.

2002-12-01

Phase transitions in minerals at elevated temperatures typically involve dynamics as a natural consequence of the increase in thermal energy available to the system. Classic examples include quartz, cristobalite, and carbonates in which the high-temperature, high symmetry phase is dynamically disordered. This disorder has important thermodynamic consequences, including displacement and curvature of phase boundaries (e.g. calcite-aragonite). In other minerals such as clinopyroxenes and anorthite feldspar, the dynamic behaviour is restricted to the neighbourhood of the phase transition. The fundamental question is whether increasing pressure generally suppresses such dynamic behaviour (as in anorthite; Angel, 1988), or not. In the latter case it must be included in thermodynamic models of high-pressure phase equilibria and seismological modelling of the mantle; the potential dynamics and softening in stishovite may provide the critical observational constraint on the presence or otherwise of free silica in the lower mantle. We have continued to use the lead phosphate as a prototype ferroelastic in which to understand dynamic behaviour, simply because its dynamics and transition behaviour is far better characterised than any mineral. Furthermore, the phase transition is at a pressure where experimental difficulties do not dominate the experimental results. Our previous neutron diffraction study (Angel et al., 2001) revealed that some disorder, either dynamic or static, is retained in the high-symmetry, high-pressure phase just above the phase transition. New neutron diffraction data on the pure material now suggests that this disorder slowly decreases with increasing pressure until at twice the transition pressure it is ordered. Further data for doped material provides insights into the nature of this disorder. Angel (1988) Amer. Mineral. 73:1114. Angel et al (2001) J PhysC 13: 5353.

Dynamics of proteins aggregation. II. Dynamic scaling in confined media

Science.gov (United States)

Zheng, Size; Shing, Katherine S.; Sahimi, Muhammad

2018-03-01

In this paper, the second in a series devoted to molecular modeling of protein aggregation, a mesoscale model of proteins together with extensive discontinuous molecular dynamics simulation is used to study the phenomenon in a confined medium. The medium, as a model of a crowded cellular environment, is represented by a spherical cavity, as well as cylindrical tubes with two aspect ratios. The aggregation process leads to the formation of β sheets and eventually fibrils, whose deposition on biological tissues is believed to be a major factor contributing to many neuro-degenerative diseases, such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis diseases. Several important properties of the aggregation process, including dynamic evolution of the total number of the aggregates, the mean aggregate size, and the number of peptides that contribute to the formation of the β sheets, have been computed. We show, similar to the unconfined media studied in Paper I [S. Zheng et al., J. Chem. Phys. 145, 134306 (2016)], that the computed properties follow dynamic scaling, characterized by power laws. The existence of such dynamic scaling in unconfined media was recently confirmed by experiments. The exponents that characterize the power-law dependence on time of the properties of the aggregation process in spherical cavities are shown to agree with those in unbounded fluids at the same protein density, while the exponents for aggregation in the cylindrical tubes exhibit sensitivity to the geometry of the system. The effects of the number of amino acids in the protein, as well as the size of the confined media, have also been studied. Similarities and differences between aggregation in confined and unconfined media are described, including the possibility of no fibril formation, if confinement is severe.

On evolutionary ray-projection dynamics

NARCIS (Netherlands)

Joosten, Reinoud A.M.G.; Roorda, Berend

2011-01-01

We introduce the ray-projection dynamics in evolutionary game theory by employing a ray projection of the relative fitness (vector) function, i.e., a projection unto the unit simplex along a ray through the origin. Ray-projection dynamics are weakly compatible in the terminology of Friedman

Dynamics of nonlinear feedback control

NARCIS (Netherlands)

Snippe, H.P.; Hateren, J.H. van

Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain

Industrial Dynamics and Economic Geography

NARCIS (Netherlands)

Capasso, Marco|info:eu-repo/dai/nl/314016627; Stam, Erik|info:eu-repo/dai/nl/215649370; Cefis, Elena|info:eu-repo/dai/nl/274516233

2015-01-01

Capasso M., Stam E. and Cefis E. Industrial dynamics and economic geography, Regional Studies. How do industries emerge and evolve over space? In this special issue the fields of industrial dynamics and economic geography are brought together in order to achieve a richer and more fundamental

System Dynamics Modelling for a Balanced Scorecard

DEFF Research Database (Denmark)

Nielsen, Steen; Nielsen, Erland Hejn

2008-01-01

/methodology/approach - We use a case study model to develop time or dynamic dimensions by using a System Dynamics modelling (SDM) approach. The model includes five perspectives and a number of financial and non-financial measures. All indicators are defined and related to a coherent number of different cause...... have a major influence on other indicators and profit and may be impossible to predict without using a dynamic model. Practical implications - The model may be used as the first step in quantifying the cause-and-effect relationships of an integrated BSC model. Using the System Dynamics model provides......Purpose - To construct a dynamic model/framework inspired by a case study based on an international company. As described by the theory, one of the main difficulties of BSC is to foresee the time lag dimension of different types of indicators and their combined dynamic effects. Design...

Complexity in Dynamical Systems

Science.gov (United States)

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.

3D dynamic pituitary MR imaging with CAIPIRINHA: Initial experience and comparison with 2D dynamic MR imaging

Energy Technology Data Exchange (ETDEWEB)

Fushimi, Yasutaka, E-mail: yfushimi@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Okada, Tomohisa; Kanagaki, Mitsunori; Yamamoto, Akira; Kanda, Yumiko; Sakamoto, Ryo [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Hojo, Masato; Takahashi, Jun C.; Miyamoto, Susumu [Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Togashi, Kaori [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan)

2014-10-15

Objectives: To evaluate the validity of 3D dynamic pituitary MR imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), with special emphasis on demarcation of pituitary posterior lobe and stalk. Methods: Participants comprised 32 patients who underwent dynamic pituitary MR imaging due to pituitary or parasellar lesions. 3D dynamic MR with CAIPIRINHA was performed at 3 T with 20-s-interval, precontrast, 1st to 5th dynamic images. Normalized values and enhanced ratios (dynamic postcontrast image values divided by precontrast ones) were compared between 3D and 2D dynamic MR imaging for patients with visual identification of posterior lobe and stalk. Results: In 3D, stalk was identified in 29 patients and unidentified in 3, and posterior lobe was identified in 28 and unidentified in 4. In 2D, stalk was identified in 26 patients and unidentified in 6 patients, and posterior lobe was identified in 15 and unidentified in 17. Normalized values of pituitary posterior lobe and stalk were higher in 3D than 2D (P < 0.001). No significant difference in enhancement ratio was seen between 3D and 2D. Conclusions: 3D dynamic pituitary MR provided better identification and higher normalized values of pituitary posterior lobe and stalk than 2D.

Effect of surface hydrophobicity on the dynamics of water at the nanoscale confinement: A molecular dynamics simulation study

International Nuclear Information System (INIS)

Choudhury, Niharendu

2013-01-01

Highlights: • We present atomistic MD simulation of water confined between two paraffin-like plates. • Effect of plate hydrophobicity on the confined water dynamics is investigated. • Diffusivity of confined water is calculated from mean squared displacements. • Rotational dynamics of the confined water has bimodal nature of relaxation. • Monotonic dependence of translational and rotational dynamics on hydrophobicity. - Abstract: We present detailed molecular dynamics simulations of water in and around a pair of plates immersed in water to investigate the effect of degree of hydrophobicity or hydrophilicity of the plates on dynamics of water confined between the two plates. The nature of the plate has been tuned from hydrophobic to hydrophilic and vice versa by varying plate-water dispersion interaction. Analyses of the translational dynamics as performed by calculating mean squared displacements of the confined water reveal a monotonically decreasing trend of the diffusivity with increasing hydrophilicity of the plates. Orientational dynamics of the confined water also follows the same monotonic trend. Although orientational time constant almost does not change with the increase of plate-water dispersion interaction in the hydrophobic regime corresponding to the smaller plate-water attraction, it changes considerably in the hydrophilic regime corresponding to larger plate-water dispersion interactions

Dynamic X-ray computed tomography

International Nuclear Information System (INIS)

Grangeat, P.

2003-01-01

Paper Dynamic computed tomography (CT) imaging aims at reconstructing image sequences where the dynamic nature of the living human body is of primary interest. Main concerned applications are image-guided interventional procedures, functional studies and cardiac imaging. The introduction of ultra-fast rotating gantries along with multi-row detectors and in near future area detectors allows a huge progress toward the imaging of moving organs with low-contrast resolution. This paper gives an overview of the different concepts used in dynamic CT. A new reconstruction algorithm based on a voxel-specific dynamic evolution compensation is also presented. It provides four-dimensional image sequences with accurate spatio-temporal information, where each frame is reconstructed using a long-scan acquisition mode on several half-turns. In the same time, this technique permits to reduce the dose delivered per rotation while keeping the same signal to noise ratio for every frame using an adaptive motion-compensated temporal averaging. Results are illustrated on simulated data. (authors)

Dynamic Contingency Analysis Tool

Energy Technology Data Exchange (ETDEWEB)

2016-01-14

The Dynamic Contingency Analysis Tool (DCAT) is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. The current prototype DCAT implementation has been developed as a Python code that accesses the simulation functions of the Siemens PSS/E planning tool (PSS/E). It has the following features: It uses a hybrid dynamic and steady-state approach to simulating the cascading outage sequences that includes fast dynamic and slower steady-state events. It integrates dynamic models with protection scheme models for generation, transmission, and load. It models special protection systems (SPSs)/remedial action schemes (RASs) and automatic and manual corrective actions. Overall, the DCAT attempts to bridge multiple gaps in cascading-outage analysis in a single, unique prototype tool capable of automatically simulating and analyzing cascading sequences in real systems using multiprocessor computers.While the DCAT has been implemented using PSS/E in Phase I of the study, other commercial software packages with similar capabilities can be used within the DCAT framework.

Dynamic analysis program for frame structure

International Nuclear Information System (INIS)

Ando, Kozo; Chiba, Toshio

1975-01-01

A general purpose computer program named ISTRAN/FD (Isub(HI) STRucture ANalysis/Frame structure, Dynamic analysis) has been developed for dynamic analysis of three-dimensional frame structures. This program has functions of free vibration analysis, seismic response analysis, graphic display by plotter and CRT, etc. This paper introduces ISTRAN/FD; examples of its application are shown with various problems : idealization of the cantilever, dynamic analysis of the main tower of the suspension bridge, three-dimensional vibration in the plate girder bridge, seismic response in the boiler steel structure, and dynamic properties of the underground LNG tank. In this last example, solid elements, in addition to beam elements, are especially used for the analysis. (auth.)

Robustness Analysis of Dynamic Watermarks

Directory of Open Access Journals (Sweden)

Ivan V. Nechta

2017-06-01

Full Text Available In this paper we consider previously known scheme of dynamic watermarks embedding (Ra- dix-n that is used for preventing illegal use of software. According to the scheme a watermark is dynamic linked data structure (graph, which is created in memory during program execution. Hidden data, such as information about author, can be represented in a different type of graph structure. This data can be extracted and demonstrated in judicial proceedings. This paper declared that the above mentioned scheme was previously one of the most reliable, has a number of features that allows an attacker to detect a stage of watermark construction in the program, and therefore it can be corrupted or deleted. The author of this article shows the weakness of Radix-N scheme, which consists in the fact that we can reveal dynamic data structures of a program by using information received from some API-functions hooker which catches function calls of dynamic memory allocation. One of these data structures is the watermark. Pointers on dynamically created objects (arrays, variables, class items, etc. of a program can be detected by content analysis of computer's RAM. Different dynamic objects in memory interconnected by pointers form dynamic data structures of a program such as lists, stacks, trees and other graphs (including the watermark. Our experiment shows that in the vast majority of cases the amount of data structure in programs is small, which increases probability of a successful attack. Also we present an algorithm for finding connected components of a graph with linear time-consuming in cases where the number of nodes is about 106. On the basis of the experimental findings the new watermarking scheme has been presented, which is resistant to the proposed attack. It is offered to use different graph structure representation of a watermark, where edges are implemented using unique signatures. Our scheme uses content encrypting of graph nodes (except signature

Predictability in community dynamics.

Science.gov (United States)

Blonder, Benjamin; Moulton, Derek E; Blois, Jessica; Enquist, Brian J; Graae, Bente J; Macias-Fauria, Marc; McGill, Brian; Nogué, Sandra; Ordonez, Alejandro; Sandel, Brody; Svenning, Jens-Christian

2017-03-01

The coupling between community composition and climate change spans a gradient from no lags to strong lags. The no-lag hypothesis is the foundation of many ecophysiological models, correlative species distribution modelling and climate reconstruction approaches. Simple lag hypotheses have become prominent in disequilibrium ecology, proposing that communities track climate change following a fixed function or with a time delay. However, more complex dynamics are possible and may lead to memory effects and alternate unstable states. We develop graphical and analytic methods for assessing these scenarios and show that these dynamics can appear in even simple models. The overall implications are that (1) complex community dynamics may be common and (2) detailed knowledge of past climate change and community states will often be necessary yet sometimes insufficient to make predictions of a community's future state. © 2017 John Wiley & Sons Ltd/CNRS.

Fractional Dynamics and Control

CERN Document Server

Machado, José; Luo, Albert

2012-01-01

Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation  Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics  Develops new methods for control and synchronization of...

Conference on Multibody Dynamics

CERN Document Server

Multibody Dynamics : Computational Methods and Applications

2014-01-01

By having its origin in analytical and continuum mechanics, as well as in computer science and applied mathematics, multibody dynamics provides a basis for analysis and virtual prototyping of innovative applications in many fields of contemporary engineering. With the utilization of computational models and algorithms that classically belonged to different fields of applied science, multibody dynamics delivers reliable simulation platforms for diverse highly-developed industrial products such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, smart structures, biomechanical applications and nano-technologies. The chapters of this volume are based on the revised and extended versions of the selected scientific papers from amongst 255 original contributions that have been accepted to be presented within the program of the distinguished international ECCOMAS conference. It reflects state-of-the-art in the advances of multibody dynamics, providing excellent insight in the recen...

An efficient finite element solution for gear dynamics

International Nuclear Information System (INIS)

Cooley, C G; Parker, R G; Vijayakar, S M

2010-01-01

A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static solution is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite element/contact mechanics formulation provides accurate calculation of the static solution and average mesh stiffness that are used in the dynamic simulation. The frequency domain finite element calculation of dynamic response compares well with numerically integrated (time domain) finite element dynamic results and previously published experimental results. Simulation time with the proposed formulation is two orders of magnitude lower than numerically integrated dynamic results. This formulation admits system level dynamic gearbox response, which may include multiple gear meshes, flexible shafts, rolling element bearings, housing structures, and other deformable components.

Dynamic modeling and dynamical analysis of pump-turbines in S-shaped regions during runaway operation

International Nuclear Information System (INIS)

Zhang, Hao; Chen, Diyi; Wu, Changzhi; Wang, Xiangyu; Lee, Jae-Myung; Jung, Kwang-Hyo

2017-01-01

Highlights: • Novel dynamic model of a pump-turbine in S-shaped regions is proposed. • A stability criterion of runaway point is given. • Global dynamic characteristics of the pump-turbine are investigated. • Effects of the slopes of the characteristic curve on the stability are studied. - Abstract: There is a region of pump-turbine operation, often called the S-shaped region, in which one unit rotational speed corresponds to three unit flows or torques. In this paper, the dynamic model of the pump-turbine in S-shaped regions is established by introducing the nonlinear piecewise function of relative parameters. Then, the global bifurcation diagrams of the pump-turbine are presented to analyze its dynamic characteristics in the S-shaped regions. Meanwhile, a stability criterion of runaway point is given based on the established theoretical model. The numerical experiments are conducted on the model and the results are in good agreement with the theoretical analysis. Furthermore, the effects of the characteristic curve slopes on the stability of the pump-turbine are studied by an innovative use of the three-dimensional bifurcation diagrams. Finally, the factors influencing the runaway stability of pump-turbines are also discussed, based on the dynamic analysis.

Dynamic Dependence and Diversification in Corporate Credit

DEFF Research Database (Denmark)

Christoffersen, Peter; Jacobs, Kris; Jin, Xisong

We characterize dependence and tail dependence in corporate credit using a new class of dynamic copula models which can capture dynamic dependence and asymmetry in large samples of firms. We also document important differences between the dependence dynamics for credit spreads and equity returns...

Polymer dynamics from synthetic polymers to proteins

Indian Academy of Sciences (India)

Keywords. Polymer dynamics; reptation; domain dynamics biomolecules. Abstract. Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the ...

Dynamic Gust Load Analysis for Rotors

Directory of Open Access Journals (Sweden)

Yuting Dai

2016-01-01

Full Text Available Dynamic load of helicopter rotors due to gust directly affects the structural stress and flight performance for helicopters. Based on a large deflection beam theory, an aeroelastic model for isolated helicopter rotors in the time domain is constructed. The dynamic response and structural load for a rotor under the impulse gust and slope-shape gust are calculated, respectively. First, a nonlinear Euler beam model with 36 degrees-of-freedoms per element is applied to depict the structural dynamics for an isolated rotor. The generalized dynamic wake model and Leishman-Beddoes dynamic stall model are applied to calculate the nonlinear unsteady aerodynamic forces on rotors. Then, we transformed the differential aeroelastic governing equation to an algebraic one. Hence, the widely used Newton-Raphson iteration algorithm is employed to simulate the dynamic gust load. An isolated helicopter rotor with four blades is studied to validate the structural model and the aeroelastic model. The modal frequencies based on the Euler beam model agree well with published ones by CAMRAD. The flap deflection due to impulse gust with the speed of 2m/s increases twice to the one without gust. In this numerical example, results indicate that the bending moment at the blade root is alleviated due to elastic effect.

Dynamic Model Averaging in Large Model Spaces Using Dynamic Occam’s Window*

Science.gov (United States)

Onorante, Luca; Raftery, Adrian E.

2015-01-01

Bayesian model averaging has become a widely used approach to accounting for uncertainty about the structural form of the model generating the data. When data arrive sequentially and the generating model can change over time, Dynamic Model Averaging (DMA) extends model averaging to deal with this situation. Often in macroeconomics, however, many candidate explanatory variables are available and the number of possible models becomes too large for DMA to be applied in its original form. We propose a new method for this situation which allows us to perform DMA without considering the whole model space, but using a subset of models and dynamically optimizing the choice of models at each point in time. This yields a dynamic form of Occam’s window. We evaluate the method in the context of the problem of nowcasting GDP in the Euro area. We find that its forecasting performance compares well with that of other methods. PMID:26917859

Dynamic pressure measures for long pipeline leak detection

Energy Technology Data Exchange (ETDEWEB)

Likun Wang; Hongchao Wang; Min Xiong; Bin Xu; Dongjie Tan; Hengzhang Zhou [PetroChina Pipeline Company, Langfang (China). R and D Center

2009-07-01

Pipeline leak detection method based on dynamic pressure is studied. The feature of dynamic pressure which is generated by the leakage of pipeline is analyzed. The dynamic pressure method is compared with the static pressure method for the advantages and disadvantages in pipeline leak detection. The dynamic pressure signal is suitable for pipeline leak detection for quick-change of pipeline internal pressure. Field tests show that the dynamic pressure method detects pipeline leak rapidly and precisely. (author)

Dynamics of curved fronts

CERN Document Server

Pelce, Pierre

1989-01-01

In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.

Manual for Dynamic Triaxial Cell

DEFF Research Database (Denmark)

Pedersen, Thomas Schmidt; Ibsen, Lars Bo

This report is a test report that describes the test setup for a dynamic triaxial cell at the Laboratory for Geotechnique at Aalborg University.......This report is a test report that describes the test setup for a dynamic triaxial cell at the Laboratory for Geotechnique at Aalborg University....

Decouplink: Dynamic Links for Java

DEFF Research Database (Denmark)

Jensen, Martin Lykke Rytter; Jørgensen, Bo Nørregaard

2011-01-01

of dimensions of extension that can be exploited without performing modification of existing types. Thus, dynamic links make it possible to enforce the open/closed principle in situations where it would otherwise not be possible. We present Decouplink – a library-based implementation of dynamic links for Java...

Dynamic Linear Models with R

CERN Document Server

Campagnoli, Patrizia; Petris, Giovanni

2009-01-01

State space models have gained tremendous popularity in as disparate fields as engineering, economics, genetics and ecology. Introducing general state space models, this book focuses on dynamic linear models, emphasizing their Bayesian analysis. It illustrates the fundamental steps needed to use dynamic linear models in practice, using R package.

Record Dynamics and the Parking Lot Model for granular dynamics

Science.gov (United States)

Sibani, Paolo; Boettcher, Stefan

Also known for its application to granular compaction (E. Ben-Naim et al., Physica D, 1998), the Parking Lot Model (PLM) describes the random parking of identical cars in a strip with no marked bays. In the thermally activated version considered, cars can be removed at an energy cost and, in thermal equilibrium, their average density increases as temperature decreases. However, equilibration at high density becomes exceedingly slow and the system enters an aging regime induced by a kinematic constraint, the fact that parked cars may not overlap. As parking an extra car reduces the available free space,the next parking event is even harder to achieve. Records in the number of parked cars mark the salient features of the dynamics and are shown to be well described by the log-Poisson statistics known from other glassy systems with record dynamics. Clusters of cars whose positions must be rearranged to make the next insertion possible have a length scale which grows logarithmically with age, while their life-time grows exponentially with size. The implications for a recent cluster model of colloidal dynamics,(S. Boettcher and P. Sibani, J. Phys.: Cond. Matter, 2011 N. Becker et al., J. Phys.: Cond. Matter, 2014) are discussed. Support rom the Villum Foundation is gratefully acknowledged.

Dynamics of Block Copolymer Nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Mochrie, Simon G. J.

2014-09-09

A detailed study of the dynamics of cadmium sulfide nanoparticles suspended in polystyrene homopolymer matrices was carried out using X-ray photon correlation spectroscopy for temperatures between 120 and 180 °C. For low molecular weight polystyrene homopolymers, the observed dynamics show a crossover from diffusive to hyper-diffusive behavior with decreasing temperatures. For higher molecular weight polystyrene, the nanoparticle dynamics appear hyper-diffusive at all temperatures studied. The relaxation time and characteristic velocity determined from the measured hyper-diffusive dynamics reveal that the activation energy and underlying forces determined are on the order of 2.14 × 10-19 J and 87 pN, respectively. We also carried out a detailed X-ray scattering study of the static and dynamic behavior of a styrene– isoprene diblock copolymer melt with a styrene volume fraction of 0.3468. At 115 and 120 °C, we observe splitting of the principal Bragg peak, which we attribute to phase coexistence of hexagonal cylindrical and cubic double- gyroid structure. In the disordered phase, above 130 °C, we have characterized the dynamics of composition fluctuations via X-ray photon correlation spectroscopy. Near the peak of the static structure factor, these fluctuations show stretched-exponential relaxations, characterized by a stretching exponent of about 0.36 for a range of temperatures immediately above the MST. The corresponding characteristic relaxation times vary exponentially with temperature, changing by a factor of 2 for each 2 °C change in temperature. At low wavevectors, the measured relaxations are diffusive with relaxation times that change by a factor of 2 for each 8 °C change in temperature.

Dynamics of nonlinear feedback control.

Science.gov (United States)

Snippe, H P; van Hateren, J H

2007-05-01

Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain signal (resp. the attenuation signal) is obtained through a concatenation of an instantaneous nonlinearity and a linear low-pass filter operating on the output of the feedback loop. For input steps, the dynamics of gain and attenuation can be very different, depending on the mathematical form of the nonlinearity and the ordering of the nonlinearity and the filtering in the feedback loop. Further, the dynamics of feedback control can be strongly asymmetrical for increment versus decrement steps of the input. Nevertheless, for each of the models studied, the nonlinearity in the feedback loop can be chosen such that immediately after an input step, the dynamics of feedback control is symmetric with respect to increments versus decrements. Finally, we study the dynamics of the output of the control loops and find conditions under which overshoots and undershoots of the output relative to the steady-state output occur when the models are stimulated with low-pass filtered steps. For small steps at the input, overshoots and undershoots of the output do not occur when the filtering in the control path is faster than the low-pass filtering at the input. For large steps at the input, however, results depend on the model, and for some of the models, multiple overshoots and undershoots can occur even with a fast control path.

Dynamic Imbalance Would Counter Offcenter Thrust

Science.gov (United States)

Mccanna, Jason

1994-01-01

Dynamic imbalance generated by offcenter thrust on rotating body eliminated by shifting some of mass of body to generate opposing dynamic imbalance. Technique proposed originally for spacecraft including massive crew module connected via long, lightweight intermediate structure to massive engine module, such that artificial gravitation in crew module generated by rotating spacecraft around axis parallel to thrust generated by engine. Also applicable to dynamic balancing of rotating terrestrial equipment to which offcenter forces applied.

Cosmological dynamics of extended chameleons

International Nuclear Information System (INIS)

Tamanini, Nicola; Wright, Matthew

2016-01-01

We investigate the cosmological dynamics of the recently proposed extended chameleon models at both background and linear perturbation levels. Dynamical systems techniques are employed to fully characterize the evolution of the universe at the largest distances, while structure formation is analysed at sub-horizon scales within the quasi-static approximation. The late time dynamical transition from dark matter to dark energy domination can be well described by almost all extended chameleon models considered, with no deviations from ΛCDM results at both background and perturbation levels. The results obtained in this work confirm the cosmological viability of extended chameleons as alternative dark energy models.

Dynamic stability under sudden loads

International Nuclear Information System (INIS)

Simitses, G.J.

1998-01-01

The concept of dynamic stability of elastic structures subjected to sudden (step) loads is discussed. The various criteria and related methodologies for estimating critical conditions are presented with the emphasis on their similarities and differences. These are demonstrated by employing a simple mechanical model. Several structural configurations are analyzed, for demonstration purposes, with the intention of comparing critical dynamic loads to critical static loads. These configurations include shallow arches and shallow spherical caps, two bar frames, and imperfect cylindrical shells of metallic as well as laminated composite construction. In the demonstration examples, the effect of static pre loading on the dynamic critical load is presented

Cosmological dynamics of extended chameleons

Energy Technology Data Exchange (ETDEWEB)

Tamanini, Nicola [Institut de Physique Théorique, CEA-Saclay, CNRS UMR 3681, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); Wright, Matthew, E-mail: nicola.tamanini@cea.fr, E-mail: matthew.wright.13@ucl.ac.uk [Department of Mathematics, University College London, Gower Street, London, WC1E 6BT (United Kingdom)

2016-04-01

We investigate the cosmological dynamics of the recently proposed extended chameleon models at both background and linear perturbation levels. Dynamical systems techniques are employed to fully characterize the evolution of the universe at the largest distances, while structure formation is analysed at sub-horizon scales within the quasi-static approximation. The late time dynamical transition from dark matter to dark energy domination can be well described by almost all extended chameleon models considered, with no deviations from ΛCDM results at both background and perturbation levels. The results obtained in this work confirm the cosmological viability of extended chameleons as alternative dark energy models.

Solving Dynamic Battlespace Movement Problems Using Dynamic Distributed Computer Networks

National Research Council Canada - National Science Library

Bradford, Robert

2000-01-01

.... The thesis designs a system using this architecture that invokes operations research network optimization algorithms to solve problems involving movement of people and equipment over dynamic road networks...

Pre Service Teachers' Usage of Dynamic Mathematics Software

Science.gov (United States)

Bulut, Mehmet; Bulut, Neslihan

2011-01-01

Aim of this study is about mathematics education and dynamic mathematics software. Dynamic mathematics software provides new opportunities for using both computer algebra system and dynamic geometry software. GeoGebra selected as dynamic mathematics software in this research. In this study, it is investigated that what is the usage of pre service…

SEVERAL PROBLEMS IN THERMOFLUID DYNAMICS

Institute of Scientific and Technical Information of China (English)

过增元

1991-01-01

A new cross-discipline, the thermofluid dynamics, has been established, which is relatedto heat transfer, fluid dynamics and thermodynamics with emphasis on the effect of thermalprocess on fluid flow. Its subject areas are (i) thermal drag, (ii) thermal roundabout flow,(iii) thermal drive and thermal instability, and (iv) thermal optimization.

Orbital free ab initio molecular dynamics simulation study of some static and dynamic properties of liquid noble metals

Directory of Open Access Journals (Sweden)

G.M. Bhuiyan

2012-10-01

Full Text Available Several static and dynamic properties of liquid Cu, Ag and Au at thermodynamic states near their respective melting points, have been evaluated by means of the orbital free ab-initio molecular dynamics simulation method. The calculated static structure shows good agreement with the available X-ray and neutron diffraction data. As for the dynamic properties, the calculated dynamic structure factors point to the existence of collective density excitations along with a positive dispersion for l-Cu and l-Ag. Several transport coefficients have been obtained which show a reasonable agreement with the available experimental data.

New technique of identifying the hierarchy of dynamic domains in proteins using a method of molecular dynamics simulations

Directory of Open Access Journals (Sweden)

Yesylevskyy S. O.

2010-04-01

Full Text Available Aim. Despite a large number of existing domain identification techniques there is no universally accepted method, which identifies the hierarchy of dynamic domains using the data of molecular dynamics (MD simulations. The goal of this work is to develop such technique. Methods. The dynamic domains are identified by eliminating systematic motions from MD trajectories recursively in a model-free manner. Results. The technique called the Hierarchical Domain-Wise Alignment (HDWA to identify hierarchically organized dynamic domains in proteins using the MD trajectories has been developed. Conclusion. A new method of domain identification in proteins is proposed

Nonlinear dynamics and numerical uncertainties in CFD

Science.gov (United States)

Yee, H. C.; Sweby, P. K.

1996-01-01

The application of nonlinear dynamics to improve the understanding of numerical uncertainties in computational fluid dynamics (CFD) is reviewed. Elementary examples in the use of dynamics to explain the nonlinear phenomena and spurious behavior that occur in numerics are given. The role of dynamics in the understanding of long time behavior of numerical integrations and the nonlinear stability, convergence, and reliability of using time-marching, approaches for obtaining steady-state numerical solutions in CFD is explained. The study is complemented with spurious behavior observed in CFD computations.

Gradient-based optimization in nonlinear structural dynamics

DEFF Research Database (Denmark)

Dou, Suguang

The intrinsic nonlinearity of mechanical structures can give rise to rich nonlinear dynamics. Recently, nonlinear dynamics of micro-mechanical structures have contributed to developing new Micro-Electro-Mechanical Systems (MEMS), for example, atomic force microscope, passive frequency divider......, frequency stabilization, and disk resonator gyroscope. For advanced design of these structures, it is of considerable value to extend current optimization in linear structural dynamics into nonlinear structural dynamics. In this thesis, we present a framework for modelling, analysis, characterization......, and optimization of nonlinear structural dynamics. In the modelling, nonlinear finite elements are used. In the analysis, nonlinear frequency response and nonlinear normal modes are calculated based on a harmonic balance method with higher-order harmonics. In the characterization, nonlinear modal coupling...

On whole Abelian model dynamics

Energy Technology Data Exchange (ETDEWEB)

Chauca, J.; Doria, R. [CBPF, Rio de Janeiro (Brazil); Aprendanet, Petropolis, 25600 (Brazil)

2012-09-24

Physics challenge is to determine the objects dynamics. However, there are two ways for deciphering the part. The first one is to search for the ultimate constituents; the second one is to understand its behaviour in whole terms. Therefore, the parts can be defined either from elementary constituents or as whole functions. Historically, science has been moving through the first aspect, however, quarks confinement and complexity are interrupting this usual approach. These relevant facts are supporting for a systemic vision be introduced. Our effort here is to study on the whole meaning through gauge theory. Consider a systemic dynamics oriented through the U(1) - systemic gauge parameter which function is to collect a fields set {l_brace}A{sub {mu}I}{r_brace}. Derive the corresponding whole gauge invariant Lagrangian, equations of motion, Bianchi identities, Noether relationships, charges and Ward-Takahashi equations. Whole Lorentz force and BRST symmetry are also studied. These expressions bring new interpretations further than the usual abelian model. They are generating a systemic system governed by 2N+ 10 classical equations plus Ward-Takahashi identities. A whole dynamics based on the notions of directive and circumstance is producing a set determinism where the parts dynamics are inserted in the whole evolution. A dynamics based on state, collective and individual equations with a systemic interdependence.

Characterizing popularity dynamics of online videos

Science.gov (United States)

Ren, Zhuo-Ming; Shi, Yu-Qiang; Liao, Hao

2016-07-01

Online popularity has a major impact on videos, music, news and other contexts in online systems. Characterizing online popularity dynamics is nature to explain the observed properties in terms of the already acquired popularity of each individual. In this paper, we provide a quantitative, large scale, temporal analysis of the popularity dynamics in two online video-provided websites, namely MovieLens and Netflix. The two collected data sets contain over 100 million records and even span a decade. We characterize that the popularity dynamics of online videos evolve over time, and find that the dynamics of the online video popularity can be characterized by the burst behaviors, typically occurring in the early life span of a video, and later restricting to the classic preferential popularity increase mechanism.

Energy Balance Models and Planetary Dynamics

Science.gov (United States)

Domagal-Goldman, Shawn

2012-01-01

We know that planetary dynamics can have a significant affect on the climate of planets. Planetary dynamics dominate the glacial-interglacial periods on Earth, leaving a significant imprint on the geological record. They have also been demonstrated to have a driving influence on the climates of other planets in our solar system. We should therefore expect th.ere to be similar relationships on extrasolar planets. Here we describe a simple energy balance model that can predict the growth and thickness of glaciers, and their feedbacks on climate. We will also describe model changes that we have made to include planetary dynamics effects. This is the model we will use at the start of our collaboration to handle the influence of dynamics on climate.