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21.
22.
从非线性自回归模型Xt+1=-αXtλ+1+βXt+γ出发,通过变量替换Xt=aYt,推出三参数混沌动力学系统模型Yt+1=kYt(1-Ytλ)+c;采用线性回归与非线性回归相结合的改进的混合法,对模型参数作了估计;实际研究表明,该模型可以用于对国内生产总值GDP增长的研究. 相似文献
23.
A scheme for vehicle density and velocity estimation in a stretch of highway based on a modified cell transmission model [C.
F. Daganzo, Transportation Research, Part B, 28B(4),269–287, 1994. Elsevier is presented. The scheme is intended for use with on-ramp metering control algorithms, providing
local knowledge of densities and velocities that is helpful to improve on-ramp metering control performance. Estimation of
density is obtained by nonlinear estimators, while velocity estimation is obtained by gradient algorithms. There is one density–velocity
estimator for free traffic flow and other for congested traffic flow. Both estimator schemes work in parallel. The final estimation
of density and velocity results from a convex combination of the predictions of the two estimators. This combination depends
on occupancy or density measurements at the boundaries of the stretch and is produced by a fuzzy inference system. Stability
and convergence of the density and velocity estimation scheme is proved by Lyapunov based techniques. Simulation results comparing
measured and estimated traffic data are presented. They confirm good performance of the estimators.
Research sponsored by grants UNAM PAPIIT IN110403 and CONACYT 47583. 相似文献
24.
We study two estimators of the long-range parameter of a covariance stationary linear process. We show that one of the estimators
achieve the optimal semiparametric rate of convergence, whereas the other has a rate of convergence as close as desired to
the optimal rate. Moreover, we show that the estimators are asymptotically normal with a variance, which does not depend on
any unknown parameter, smaller than others suggested in the literature. Finally, a small Monte Carlo study is included to
illustrate the finite sample relative performance of our estimators compared to other suggested semiparametric estimators.
More specifically, the Monte-Carlo experiment shows the superiority of the proposed estimators in terms of the Mean Squared
Error.
The first author research was funded by the Economic and Social Research Council (ESRC) reference number: R000238212. The
second author research was funded by the Ministry of Education, Culture, Sports and Technology of Japan, reference number:
09CE2002 and B(2)10202202. 相似文献
25.
文章讨论无界区域上GBBM方程的Cauchy问题,对方程的解进行了先验估计,并证明了在H1弱拓扑中整体吸引子的存在性. 相似文献
26.
Supply Chain Management (SCM) is an important activity in all producing facilities and in many organizations to enable vendors,
manufacturers and suppliers to interact gainfully and plan optimally their flow of goods and services. To realize this, a
dynamic modelling approach for characterizing supply chain activities is opportune, so as to plan efficiently the set of activities
over a distributed network in a formal and scientific way. The dynamical system will result so complex that it is not generally
possible to specify the functional forms and the parameters of interest, relating outputs to inputs, states and stochastic
terms by experiential specification methods. Thus the algorithm that will presented is Data Driven, determining simultaneously
the functional forms, the parameters and the optimal control policy from the data available for the supply chain. The aim
of this paper is to present this methodology, by considering dynamical aspects of the system, the presence of nonlinear relationships
and unbiased estimation procedures to quantify these relations, leading to a nonlinear and stochastic dynamical system representation
of the SCM problem. Moreover, the convergence of the algorithm will be proved and the satisfaction of the required statistical
conditions demonstrated. Thus SCM problems may be formulated as formal scientific procedures, with well defined algorithms
and a precise calculation sequence to determine the best alternative to enact. A “Certainty equivalent principle” will be
indicated to ensure that the effects of the inevitable uncertainties will not lead to indeterminate results, allowing the
formulation of demonstrably asymptotically optimal management plans. 相似文献
27.
How can the basic compatibility of theory and observations be investigated for nonlinear processes without requiring stochastic characterizations for residual error terms? The present paper proposes a flexible least-cost approach. For each possible estimatex for the sequence of process states, letc D (x) andx M(x) denote the costs incurred for deviations away from the prior dynamic specifications and prior measurement specifications, respectively. Define the cost-efficiency frontier to be the greatest lower bound for the set of all possible cost pairs [c D (x),c M(x)], conditional on the given observations. State sequence estimatesx that attain the cost-efficiency frontier indicate the possible ways that the actual process could have developed over time in a manner minimally incompatible with the prior dynamic and measurement specifications. An algorithm is developed for the exact sequential updating of the cost-efficient state sequence estimates as the duration of the process increases and additional observations are obtained. 相似文献
28.
R. S. Kaler 《Fiber and Integrated Optics》2006,25(1):41-57
In this article, the comparison of large signal theory and small signal theory has been done with dispersive propagation of optical signal with IMDD (Intensity Modulation Direct Detection) systems for semiconductor lasers with higher-order dispersion terms. The expressions for an exact large signal theory and small signal theory including higher-order dispersion terms for propagation of an optical wave with sinusoidal amplitude and frequency modulation in a dispersive fiber have been derived. It is observed that small signal theory is more sensitive compared to large signal theory in terms of intensity modulation/direct detection systems. Also, it is reported that for large signal analysis the higher-order effects of dispersion can be ignored, whereas for small signal theory, the higher-order effects can be ignored for lower modulation frequencies only. The variation in the transfer function for various values of modulation indices are greater for small signal analysis than for large signal analysis. Also, as the intensity modulation index is increased, there is a decrease in the value of transfer function. The large signal model approximates the small signal model for lower values of the intensity modulation index. 相似文献
29.
用射频磁控溅射结合传统退火的方法制备LiCo0.8M0.2O2 (M=Ni,Zr)阴极薄膜.X射线衍射、拉曼光谱、扫描电子显微镜等手段表征了不同掺杂的LiCo0.8M0.2O2薄膜.结果显示,700℃退火的LiCo0.8M0.2O2薄膜具有类似α-NaFeO2的层状结构.通过对不同掺杂锂钴氧阴极的全固态薄膜锂电池Li/LiPON/LiCo0.8M0.2O2的电化学性能研究表明,电化学活性元素Ni的掺杂使全固态电池具有更大的放电容量(56μAh/cm2μm),而非电化学活性元素Zr的掺杂使全固态电池具有更好的循环稳定性. 相似文献
30.
On a recursive method for the estimation of unknown parameters of partially observed chaotic systems
We investigate a recently proposed method for on-line parameter estimation and synchronization in chaotic systems. This novel technique has been shown effective to estimate a single unknown parameter of a primary chaotic system with known functional form that is only partially observed through a scalar time series. It works by periodically updating the parameter of interest in a secondary system, with the same functional form as the primary one but no explicit coupling between their dynamic variables, in order to minimize a suitably defined cost function. In this paper, we review the basics of the method, and investigate its robustness and new extensions. In particular, we study the performance of the novel technique in the presence of noise (either observational, i.e., an additive contamination of the observed time series, or dynamical, i.e., a random perturbation of the system dynamics) and when there is a mismatch between the primary and secondary systems. Numerical results, including comparisons with other techniques, are presented. Finally, we investigate the extension of the original method to perform the estimation of two unknown parameters and illustrate its effectiveness by means of computer simulations. 相似文献