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INVARIANCE AND STABILITY OF THE PROFILE EQUATIONS OF GEOMETRIC OPTICS
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作者 Guy Mtivier Jeffrey Rauch 《Acta Mathematica Scientia》 SCIE CSCD 2011年第6期2141-2158,共18页
The profile equations of geometric optics are described in a form invariant under the natural transformations of first order systems of partial differential equations. This allows us to prove that various strategies f... The profile equations of geometric optics are described in a form invariant under the natural transformations of first order systems of partial differential equations. This allows us to prove that various strategies for computing profile equations are equivalent. We prove that if L generates an evolution on L2 the same is true of the profile equations. We prove that the characteristic polynomial of the profile equations is the localization of the characteristic polynomial of the background operator at (y, dφ(y)) where φ is the background phase. We prove that the propagation cones of the profile equations are subsets of the propagation cones of the background operator. 展开更多
关键词 geometric optics profile equation LOCALISATION vector bundles propagation cones
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Asymptotically efficient parameter estimation for ordinary differential equations
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作者 PANG TianXiao YAN PeiSi ZHOU Harrison H. 《Science China Mathematics》 SCIE CSCD 2017年第11期2263-2286,共24页
Parameter estimation for ordinary differential equations arises in many fields of science and engineering. To be the best of our knowledge, traditional methods are often either computationally intensive or inaccurate ... Parameter estimation for ordinary differential equations arises in many fields of science and engineering. To be the best of our knowledge, traditional methods are often either computationally intensive or inaccurate for statistical inference. Ramsay et al.(2007) proposed a generalized profiling procedure. It is easily implementable and has been demonstrated to have encouraging numerical performance. However, little is known about statistical properties of this procedure. In this paper, we provide a theoretical justification of the generalized profiling procedure. Under some regularity conditions, the procedure is shown to be consistent for a broad range of tuning parameters. When the tuning parameters are sufficiently large, the procedure can be further shown to be asymptotically normal and efficient. 展开更多
关键词 asymptotic efficiency consistency generalized profiling procedure ordinary differential equations splines
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Dynamical Behavior of Solution in Integrable Nonlocal Lakshmanan–Porsezian–Daniel Equation
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作者 柳伟 邱德勤 +1 位作者 吴志伟 贺劲松 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第6期671-676,共6页
The integrable nonlocal Lakshmanan–Porsezian–Daniel(LPD) equation which has the higher-order terms(dispersions and nonlinear effects) is first introduced. We demonstrate the integrability of the nonlocal LPD equatio... The integrable nonlocal Lakshmanan–Porsezian–Daniel(LPD) equation which has the higher-order terms(dispersions and nonlinear effects) is first introduced. We demonstrate the integrability of the nonlocal LPD equation,provide its Lax pair, and present its rational soliton solutions and self-potential function by using the degenerate Darboux transformation. From the numerical plots of solutions, the compression effects of the real refractive index profile and the gain-or-loss distribution produced by δ are discussed. 展开更多
关键词 nonlocal Lakshmanan–Porsezian–Daniel equation parity-time-symmetry higher-order nonlinear effect refractive index profile gain-or-loss distribution
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