Young, L.S (LaiSang)
Overview
Works:  13 works in 49 publications in 2 languages and 822 library holdings 

Genres:  Conference papers and proceedings Academic theses 
Roles:  Editor, Author 
Publication Timeline
.
Most widely held works by
L.S Young
Geometries and groups : proceedings of a colloquium held at the Freie Universität, Berlin May 1981 by
Helmut Cajar(
Book
)
24 editions published between 1981 and 2008 in English and German and held by 625 WorldCat member libraries worldwide
24 editions published between 1981 and 2008 in English and German and held by 625 WorldCat member libraries worldwide
Strange attractors for periodically forced parabolic equations by
Kening Lu(
Book
)
10 editions published in 2013 in English and held by 179 WorldCat member libraries worldwide
"We prove that in systems undergoing Hopf bifurcations, the effects of periodic forcing can be amplified by the shearing in the system to create sustained chaotic behavior. Specifically, strange attractors with SRB measures are shown to exist. The analysis is carried out for infinite dimensional systems, and the results are applicable to partial differential equations. Application of the general results to a concrete equation, namely the Brusselator, is given."Page v
10 editions published in 2013 in English and held by 179 WorldCat member libraries worldwide
"We prove that in systems undergoing Hopf bifurcations, the effects of periodic forcing can be amplified by the shearing in the system to create sustained chaotic behavior. Specifically, strange attractors with SRB measures are shown to exist. The analysis is carried out for infinite dimensional systems, and the results are applicable to partial differential equations. Application of the general results to a concrete equation, namely the Brusselator, is given."Page v
Intersection theory in 3dimensional linearized contact homology by Al Momin(
)
1 edition published in 2008 in English and held by 5 WorldCat member libraries worldwide
The main technical tool is an intersection product on the compactified moduli spaces of Symplectic Field Theory, inspired by the study of asymptotic intersections of Siefring in his thesis [27]. This intersection product is shown to be continuous with respect to the SFT topology in some very simple cases
1 edition published in 2008 in English and held by 5 WorldCat member libraries worldwide
The main technical tool is an intersection product on the compactified moduli spaces of Symplectic Field Theory, inspired by the study of asymptotic intersections of Siefring in his thesis [27]. This intersection product is shown to be continuous with respect to the SFT topology in some very simple cases
The metric entropy of diffeomorphism by
F Ledrappier(
Book
)
3 editions published in 1984 in English and held by 3 WorldCat member libraries worldwide
3 editions published in 1984 in English and held by 3 WorldCat member libraries worldwide
The metric entropy of diffeomorphisms by
F Ledrappier(
Book
)
2 editions published in 1984 in English and held by 3 WorldCat member libraries worldwide
2 editions published in 1984 in English and held by 3 WorldCat member libraries worldwide
Invariant measures for degenerate random perturbations of discretetime dynamical systems by Tatiana Yarmola(
Book
)
1 edition published in 2008 in English and held by 2 WorldCat member libraries worldwide
Random perturbations of dynamical systems is an important tool in modeling noise and other types of uncontrolled fluctuations. In many reallife systems, fluctuations do not occur everywhere or uniformly in all directions; some of these situations can be modeled by localized, degenerate noise. In this thesis, we focus on random perturbations of discretetime dynamical systems that occur in a single direction; we call these rank one perturbations. The aim of this work is to study whether such perturbations lead to invariant measures that are absolutely continuous with respect to Lebesgue measure
1 edition published in 2008 in English and held by 2 WorldCat member libraries worldwide
Random perturbations of dynamical systems is an important tool in modeling noise and other types of uncontrolled fluctuations. In many reallife systems, fluctuations do not occur everywhere or uniformly in all directions; some of these situations can be modeled by localized, degenerate noise. In this thesis, we focus on random perturbations of discretetime dynamical systems that occur in a single direction; we call these rank one perturbations. The aim of this work is to study whether such perturbations lead to invariant measures that are absolutely continuous with respect to Lebesgue measure
Nonlinear Hawkes Processes by
Lingjiong Zhu(
Book
)
1 edition published in 2013 in English and held by 1 WorldCat member library worldwide
The Hawkes process is a simple point process that has long memory, clustering effect, selfexciting property and is in general nonMarkovian. The future evolution of a selfexciting point process is influenced by the timing of the past events. There are applications in finance, neuroscience, genome analysis, seismology, sociology, criminology and many other fields. We first survey the known results about the theory and applications of both linear and nonlinear Hawkes processes. Then, we obtain the central limit theorem and processlevel, i.e. level3 large deviations for nonlinear Hawkes processes. The level1 large deviation principle holds as a result of the contraction principle. We also provide an alternative variational formula for the rate function of the level1 large deviations in the Markovian case. Next, we drop the usual assumptions on the nonlinear Hawkes process and categorize it into different regimes, i.e. sublinear, subcritical, critical, supercritical and explosive regimes. We show the different time asymptotics in different regimes and obtain other properties as well. Finally, we study the limit theorems of linear Hawkes processes with random marks
1 edition published in 2013 in English and held by 1 WorldCat member library worldwide
The Hawkes process is a simple point process that has long memory, clustering effect, selfexciting property and is in general nonMarkovian. The future evolution of a selfexciting point process is influenced by the timing of the past events. There are applications in finance, neuroscience, genome analysis, seismology, sociology, criminology and many other fields. We first survey the known results about the theory and applications of both linear and nonlinear Hawkes processes. Then, we obtain the central limit theorem and processlevel, i.e. level3 large deviations for nonlinear Hawkes processes. The level1 large deviation principle holds as a result of the contraction principle. We also provide an alternative variational formula for the rate function of the level1 large deviations in the Markovian case. Next, we drop the usual assumptions on the nonlinear Hawkes process and categorize it into different regimes, i.e. sublinear, subcritical, critical, supercritical and explosive regimes. We show the different time asymptotics in different regimes and obtain other properties as well. Finally, we study the limit theorems of linear Hawkes processes with random marks
Mathematical Study of Milestoning by Ling Lin(
Book
)
1 edition published in 2013 in English and held by 1 WorldCat member library worldwide
Milestoning is a coarsegraining strategy that can serve both as an analysis tool to analyze time series of complicated activated processes and as a computational tool to accelerate the computation of these processes. It can be used, e.g., in the context of molecular dynamics simulations. In this thesis, a solid mathematical foundation of milestoning is presented. For systems displaying metastability, the assumption of Markovian milestoning can be justified asymptotically provided that the metastable states are taken as milestones. Practically, the set of the metastable states can be identified automatically as the set that minimizes a metastability index, and a continuoustime Markov jump process can be built on this set by applying maximum likelihood estimation and Bayesian sampling techniques. For systems without the timescale separation, the assumption of optimal milestoning can still be justified for the set of milestones made of the forward isocommittor surfaces, which allows us to build a discretetime Markov chain on the index set of milestones. For diffusion processes, under mild assumptions, by using a set of milestones made of the backward isocommittor surfaces, the mean first passage times between milestones can be calculated exactly. In practice, the isocommittor surfaces can be identified approximately as the hyperplanes in the reaction tube by using the string method, and an accelerated sampling procedure based on the confined simulations in Voronoi cells can compute the required key objects in milestoning efficiently without the need to reinitialize simulations on milestones
1 edition published in 2013 in English and held by 1 WorldCat member library worldwide
Milestoning is a coarsegraining strategy that can serve both as an analysis tool to analyze time series of complicated activated processes and as a computational tool to accelerate the computation of these processes. It can be used, e.g., in the context of molecular dynamics simulations. In this thesis, a solid mathematical foundation of milestoning is presented. For systems displaying metastability, the assumption of Markovian milestoning can be justified asymptotically provided that the metastable states are taken as milestones. Practically, the set of the metastable states can be identified automatically as the set that minimizes a metastability index, and a continuoustime Markov jump process can be built on this set by applying maximum likelihood estimation and Bayesian sampling techniques. For systems without the timescale separation, the assumption of optimal milestoning can still be justified for the set of milestones made of the forward isocommittor surfaces, which allows us to build a discretetime Markov chain on the index set of milestones. For diffusion processes, under mild assumptions, by using a set of milestones made of the backward isocommittor surfaces, the mean first passage times between milestones can be calculated exactly. In practice, the isocommittor surfaces can be identified approximately as the hyperplanes in the reaction tube by using the string method, and an accelerated sampling procedure based on the confined simulations in Voronoi cells can compute the required key objects in milestoning efficiently without the need to reinitialize simulations on milestones
Synchronization and phaselocking of coupled oscillators by Brian Ryals(
Book
)
1 edition published in 2013 in English and held by 1 WorldCat member library worldwide
At epsilon = 0, the dynamical system reduces to a piecewise linear contraction with discontinuity. At epsilon= 1/2, the system bears nontrivial similarity to the Kuramoto model. The case epsilon = 0 is explored first, and it is used as a basis for exploring systems corresponding to epsilon> 0. It will be shown analytically that for epsilon = 0 there are finitely many phaselocked solutions and that they obey certain structural conditions. The idea of clustering will be developed, and theorems will be proved concerning the possible number of clusters a phaselocked solution can have. It will also be argued that there is a signicant difference between odd and even N. Numerical results on the basins of attraction will also be given. These simulations suggest that when the basins are grouped by cluster number they obey simple properties, in particular monotonicty and a 1/sqrt(N) scaling law
1 edition published in 2013 in English and held by 1 WorldCat member library worldwide
At epsilon = 0, the dynamical system reduces to a piecewise linear contraction with discontinuity. At epsilon= 1/2, the system bears nontrivial similarity to the Kuramoto model. The case epsilon = 0 is explored first, and it is used as a basis for exploring systems corresponding to epsilon> 0. It will be shown analytically that for epsilon = 0 there are finitely many phaselocked solutions and that they obey certain structural conditions. The idea of clustering will be developed, and theorems will be proved concerning the possible number of clusters a phaselocked solution can have. It will also be argued that there is a signicant difference between odd and even N. Numerical results on the basins of attraction will also be given. These simulations suggest that when the basins are grouped by cluster number they obey simple properties, in particular monotonicty and a 1/sqrt(N) scaling law
Dynamical systems and turbulence, 1980 : proceedings of a symposium held at the University of Warwick 1979/80(
)
1 edition published in 1981 in English and held by 1 WorldCat member library worldwide
1 edition published in 1981 in English and held by 1 WorldCat member library worldwide
The metric entropy of diffeomorphisms by
F Ledrappier(
Book
)
2 editions published in 1984 in English and held by 0 WorldCat member libraries worldwide
2 editions published in 1984 in English and held by 0 WorldCat member libraries worldwide
The manufacture of news; a reader by
Stanley Cohen(
Book
)
1 edition published in 1973 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 1973 in English and held by 0 WorldCat member libraries worldwide
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Related Identities
 Rand, D. A. (David A.) Author Editor
 University of Warwick
 Wang, Qiudong 1962
 Lu, Kening 1962 Author
 Ledrappier, F. Author
 Momin, Al Author
 Cappell, Sylvain
 Johns, Joseph
 Tschinkel, Yuri
 Gunturk, Sinan
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Associated Subjects
Alexander ideals Algebra Algebraic spaces Attractors (Mathematics) Canada Combinatorial analysis Differentiable dynamical systems Differential equations Differential equations, Parabolic Differential equations, Partial Dimension theory (Algebra) Fluids Geometry Geometry, Algebraic Group theory Induction (Mathematics) JournalismSocial aspects Knot theory Logic, Symbolic and mathematical Mathematical analysisFoundations Mathematical physics Mathematics Number theory Periodic functions Physics Probabilistic number theory Probabilities Proof theory Scientists Turbulence United States
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Alternative Names
LaiSang Young.
LaiSang Young American mathematician
LaiSang Young Amerikaans wiskundige
LaiSang Young matemática estadounidense
LaiSang Young Mathématicienne américaine
LaiSang Young USamerikanische Mathematikerin
Young, L.S.
Young, L.S. 1952
Young, LaiSang
לאי סאנג יאנג מתמטיקאית אמריקאית
لای سنگ یانگ ریاضیدان آمریکایی
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