In this paper, by means of combining non-probabilistic convex modeling with perturbation theory, an improvement is made on the first order approximate solution in convex models of uncertainties. Convex modeling is ext...In this paper, by means of combining non-probabilistic convex modeling with perturbation theory, an improvement is made on the first order approximate solution in convex models of uncertainties. Convex modeling is extended to largely uncertain and non-convex sets of uncertainties and the combinational convex modeling is developed. The presented method not only extends applications of convex modeling, but also improves its accuracy in uncertain problems and computational efficiency. The numerical example illustrates the efficiency of the proposed method.展开更多
VISCAL （VISSIM calibration） is an automated calibration tool for microscopic simulation parameters in VISSIM environment, based on three heuristic optimization algorithms： （a） genetic algorithm （GA）; Col simult...VISCAL （VISSIM calibration） is an automated calibration tool for microscopic simulation parameters in VISSIM environment, based on three heuristic optimization algorithms： （a） genetic algorithm （GA）; Col simultaneous perturbation stochastic approximation （SPSA）; （c） simulated annealing （SA）. It is developed with a goal to automate and ease the tedious process of calibration, offering greater flexibility to the users by providing control on every aspect of the calibration process. It includes multiple features for a generic application tool with the ability to test the significance of the appropriate decision parameter set for a particular network, to determine the most suitable objective function to reflect network characteristics, and to check the suitability of any of the three heuristic optimization al- gorithms for a particular network. VISCAL also offers four objective function choices into the system： （1） speed, （2） flow, （3） delay, and （4） multi-objective criteria. It is able to calibrate all the driving behavior parameters for any type （urban, rural） and extent of network （small or large network）. However, for this study, the operation of the tool is tested by a dataset obtained from a 3.26 km freeway of Dhaka, Bangladesh.展开更多
The perturbation solution of axial and secondary flow behavior in a curved annular duct was presented. First, a nonorthogonal cylindrical coordinate system was introduced. Second, the Navier-Stokes equations and conti...The perturbation solution of axial and secondary flow behavior in a curved annular duct was presented. First, a nonorthogonal cylindrical coordinate system was introduced. Second, the Navier-Stokes equations and continuity equation were established in tensorial form. The zeroth-order, first-order and second-order analytic perturbation solutions were obtained. It is found that there is a secondary flow in the annular section, and four recirculating cells in the cross section.展开更多
In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochast...In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochastic approximation algorithm is proposed by integrating neural network with fuzzy simulation. At first, fuzzy simulation is used to generate a set of input-output data. Then a neural network is trained according to the set. Finally, the trained neural network is embedded in simultaneous perturbation stochastic approximation algorithm. Simultaneous perturbation stochastic approximation algorithm is used to search the optimal solution. Two numerical examples are presented to illustrate the effectiveness of the proposed algorithm.展开更多
In the field of geophysics,although the first-order Rytov approximation is widely used,the higher-order approximation is seldom discussed.From both theo-retical analysis and numerical tests,the accumulated phase error...In the field of geophysics,although the first-order Rytov approximation is widely used,the higher-order approximation is seldom discussed.From both theo-retical analysis and numerical tests,the accumulated phase error introduced in the first-order Rytov approximation cannot be neglected in the presence of strong velocity perturbation.In this paper,we are focused on improving the phase accuracy of forward scattered wavefield,especially for the large-scale and strong velocity pertur-bation case.We develop an equivalent source method which can update the imaginary part of the complex phase iteratively,and the higher-order scattered wavefield can be approximated by multiplying the incident wavefield by the exponent of the imaginary part of the complex phase.Although the convergence of the proposed method has not been proved mathematically,numerical examples demonstrate that our method can produce an improved accuracy for traveltime(phase)prediction,even for strong perturbation media.However,due to the neglect of the real part of the complex phase,the amplitude change of the scattered wavefield cannot be recovered.Furthermore,in the presence of multi-arrivals phenomenon,the equivalent scattering source should be handled carefully due to the multi-directions of the wavefield.Further investigations should be done to improve the applicability of the proposed method.展开更多
In this paper the dynamical equations for an elastic deformable body in the first post-Newtonian approximation of Einstein theory of gravity are derived in rotating spherical coordinates. The unperturbed rotating body...In this paper the dynamical equations for an elastic deformable body in the first post-Newtonian approximation of Einstein theory of gravity are derived in rotating spherical coordinates. The unperturbed rotating body (the relaxed ground state) is described as uniformly rotating, stationary and axisymmetric configuration in an asymptotically flat space-time manifold. Deviations from the equilibrium configuration are described by means of a displacement field. By making use of the schemes developed by Damour, Soffel and Xu, and by Carter and Quintana we calculate the post-Newtonian Lagrangian strain tensor and symmetric trace-free shear tensor. Considering the Euler variations of Einstein's energy-momentum conservation law, we derive the post- Newtonian energy equation and Euler equations of elastic deformable bodies in rotating spherical coordinates.展开更多
Based on statistical mechanics, a review of recent theoretical studies of real electrolyte solutions is presented from three aspects, namely, molecular simulation, mean spherical approximation (MSA), and perturbation ...Based on statistical mechanics, a review of recent theoretical studies of real electrolyte solutions is presented from three aspects, namely, molecular simulation, mean spherical approximation (MSA), and perturbation theory. Recent advances in studies of three kinds of electrostatic potentials of mean force, three kinds of internal energies (ion-ion, ion-dipole, and dipole-dipole interactions), and three kinds of electro-lyte models (primitive, non-primitive, and solvent primitive models) are introduced. The advantages and dis-advantages between primitive and non-primitive models, and between MSA and perturbation theory are dis-cussed. Some new equations of state (EOSs) based on MSA and perturbation theory for real electrolyte so-lutions are introduced. The one-Yukawa EOS and the two-Yukawa EOS for charged colloid systems are presented.展开更多
On the basis of the perturbation, we present an approach to approximating rational surfaces by the interval Btzier surfaces using energy minimization method. The approach makes the perturbation surfaces have more rest...On the basis of the perturbation, we present an approach to approximating rational surfaces by the interval Btzier surfaces using energy minimization method. The approach makes the perturbation surfaces have more restrictions than the original surfaces. It could be combined with subdivision method to obtain a piecewise interval polynomial approximation for a rational surface. The applications of this approach are illustrated too.展开更多
基金The project supported by the National Outstanding Youth Science Foundation of China the National Post Doctor Science Foundation of China
文摘In this paper, by means of combining non-probabilistic convex modeling with perturbation theory, an improvement is made on the first order approximate solution in convex models of uncertainties. Convex modeling is extended to largely uncertain and non-convex sets of uncertainties and the combinational convex modeling is developed. The presented method not only extends applications of convex modeling, but also improves its accuracy in uncertain problems and computational efficiency. The numerical example illustrates the efficiency of the proposed method.
基金supported by the Committee for Advanced Studies and Research (CASR)Bangladesh University of Engineering and Technology (BUET)
文摘VISCAL （VISSIM calibration） is an automated calibration tool for microscopic simulation parameters in VISSIM environment, based on three heuristic optimization algorithms： （a） genetic algorithm （GA）; Col simultaneous perturbation stochastic approximation （SPSA）; （c） simulated annealing （SA）. It is developed with a goal to automate and ease the tedious process of calibration, offering greater flexibility to the users by providing control on every aspect of the calibration process. It includes multiple features for a generic application tool with the ability to test the significance of the appropriate decision parameter set for a particular network, to determine the most suitable objective function to reflect network characteristics, and to check the suitability of any of the three heuristic optimization al- gorithms for a particular network. VISCAL also offers four objective function choices into the system： （1） speed, （2） flow, （3） delay, and （4） multi-objective criteria. It is able to calibrate all the driving behavior parameters for any type （urban, rural） and extent of network （small or large network）. However, for this study, the operation of the tool is tested by a dataset obtained from a 3.26 km freeway of Dhaka, Bangladesh.
文摘The perturbation solution of axial and secondary flow behavior in a curved annular duct was presented. First, a nonorthogonal cylindrical coordinate system was introduced. Second, the Navier-Stokes equations and continuity equation were established in tensorial form. The zeroth-order, first-order and second-order analytic perturbation solutions were obtained. It is found that there is a secondary flow in the annular section, and four recirculating cells in the cross section.
基金National Natural Science Foundation of China (No.70471049)China Postdoctoral Science Foundation (No. 20060400704)
文摘In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochastic approximation algorithm is proposed by integrating neural network with fuzzy simulation. At first, fuzzy simulation is used to generate a set of input-output data. Then a neural network is trained according to the set. Finally, the trained neural network is embedded in simultaneous perturbation stochastic approximation algorithm. Simultaneous perturbation stochastic approximation algorithm is used to search the optimal solution. Two numerical examples are presented to illustrate the effectiveness of the proposed algorithm.
基金supported by National Natural Science Foundation of China(41604091,41704111,41774126)the great and special project(2016ZX05024-001,2016ZX05006-002).
文摘In the field of geophysics,although the first-order Rytov approximation is widely used,the higher-order approximation is seldom discussed.From both theo-retical analysis and numerical tests,the accumulated phase error introduced in the first-order Rytov approximation cannot be neglected in the presence of strong velocity perturbation.In this paper,we are focused on improving the phase accuracy of forward scattered wavefield,especially for the large-scale and strong velocity pertur-bation case.We develop an equivalent source method which can update the imaginary part of the complex phase iteratively,and the higher-order scattered wavefield can be approximated by multiplying the incident wavefield by the exponent of the imaginary part of the complex phase.Although the convergence of the proposed method has not been proved mathematically,numerical examples demonstrate that our method can produce an improved accuracy for traveltime(phase)prediction,even for strong perturbation media.However,due to the neglect of the real part of the complex phase,the amplitude change of the scattered wavefield cannot be recovered.Furthermore,in the presence of multi-arrivals phenomenon,the equivalent scattering source should be handled carefully due to the multi-directions of the wavefield.Further investigations should be done to improve the applicability of the proposed method.
基金the National Natural Seienee Foundation of China(Grant Nos.10273008 and 19835040)the German Scienee Foundation(DFG)
文摘In this paper the dynamical equations for an elastic deformable body in the first post-Newtonian approximation of Einstein theory of gravity are derived in rotating spherical coordinates. The unperturbed rotating body (the relaxed ground state) is described as uniformly rotating, stationary and axisymmetric configuration in an asymptotically flat space-time manifold. Deviations from the equilibrium configuration are described by means of a displacement field. By making use of the schemes developed by Damour, Soffel and Xu, and by Carter and Quintana we calculate the post-Newtonian Lagrangian strain tensor and symmetric trace-free shear tensor. Considering the Euler variations of Einstein's energy-momentum conservation law, we derive the post- Newtonian energy equation and Euler equations of elastic deformable bodies in rotating spherical coordinates.
基金the Fundamental Research Fund of Tsinghua University of China (No. JZ 2002003)
文摘Based on statistical mechanics, a review of recent theoretical studies of real electrolyte solutions is presented from three aspects, namely, molecular simulation, mean spherical approximation (MSA), and perturbation theory. Recent advances in studies of three kinds of electrostatic potentials of mean force, three kinds of internal energies (ion-ion, ion-dipole, and dipole-dipole interactions), and three kinds of electro-lyte models (primitive, non-primitive, and solvent primitive models) are introduced. The advantages and dis-advantages between primitive and non-primitive models, and between MSA and perturbation theory are dis-cussed. Some new equations of state (EOSs) based on MSA and perturbation theory for real electrolyte so-lutions are introduced. The one-Yukawa EOS and the two-Yukawa EOS for charged colloid systems are presented.
基金Project supported by Inner Mongolia University of Science and Technology (No.X200829)
文摘On the basis of the perturbation, we present an approach to approximating rational surfaces by the interval Btzier surfaces using energy minimization method. The approach makes the perturbation surfaces have more restrictions than the original surfaces. It could be combined with subdivision method to obtain a piecewise interval polynomial approximation for a rational surface. The applications of this approach are illustrated too.
