关于布朗运动过程的最佳非线性预测

本文将研究非线性预测理论中的一些问题。首先,取标准布朗运动过程X(t)为基础过程,然后用满足一定条件的Borel可测函数f,把X(t)进行变换而得到新的随机过程f(X(t))。这样,实际能够观测到的过程就是形如Y(t)=f(X(t))的随机过程。本文的主要目的就是,利用观测值Y(f),r≤t来求Y(t+τ)、τ>0的最佳非线性预测量Y(t,τ)。其次,取带漂移布朗运动过程为基础过程,而后用如上的方法作出新的随机过程。从而,讨论怎样求这种过程的最佳非线性预测量问题。     

Peer nominations on leadership as a predictor of the pass-fail criterion in naval air training.

After three months of pre-flight training, nine sections of cadets (N=268) were asked to nominate the three best-qualified and the three least qualified for military leadership in their sections. The leadership scores, ACE Test scores, Officer-Like-Qualities grade assigned by officers in charge, and final overall pre-flight average were correlated with a pass-fail criterion of flight training. The leadership score and the final pre-flight average were about equally predictive of the criterion (r of .27 and .28, respectively). The other two measures failed to correlate significantly with the criterion. A rationale for the predictive value of peer ratings for flight training success is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimating the number of different selection decisions resulting from the use of alternate predictor composites.

A method was described whereby d, the number of different selection decisions resulting from the use of alternate predictor composites may be rapidly estimated from the proportion of applicants accepted and the correlation between the composites. It was further demonstrated that the correlation between 2 optimally weighted composites based upon m and n variables (m n) is equal to the ratio of the 2 multiple correlations. 2 examples were used to illustrate the use of d in evaluating selection strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Supporting multi-user real-time VBR video service using dynamic bandwidth management based on prediction

Real-time variable bit rate (VBR) video is expected to take a significant portion of multimedia applications. However, plentiful challenges to VBR video service provision have been raised for its characteristic of high traffic abruptness. To support multi-user real-time VBR video transmission with high bandwidth utilization and satisfied quality of service (QoS), this article proposes a practical dynamic bandwidth management scheme. This scheme forecasts future media rate of VBR video by employing time-domain adaptive linear predictor and using media delivery index (MDI) as both QoS measurement and complementary management reference. In addition, to support multi-user application, an adjustment priorities classified strategy is also put forward. Finally, a test-bed based on this management scheme is established. The experimental results demonstrate that the scheme proposed in this article is efficient with bandwidth utilization increased by 20%-60% compared to a fixed service rate and QoS guaranteed.     

带有扰动补偿的永磁同步电机自适应预测控制

为保证永磁同步电机(PMSM)控制系统的稳定性和鲁棒性,提出一种基于小波神经网络的自适应Smith预测控制器(WNNSPC),通过对模型误差的补偿,消除模型不确定性的影响,保证了预测输出的准确性,同时针对电机运行中突加负载等的扰动,采用小波神经网络进行前馈补偿,有效抑制了各类扰动对系统的影响,而且具有良好的动、静态品质。仿真结果证明了提出方法的有效性。     

带积分的模糊Smith预估器在电加热温度控制中的应用

传统的smith预估器是解决大纯滞后系统控制的有效方法,但它依赖于被控对象精确的数学模型,使应用受到了限制。带积分的模糊smith预估器兼有前者的特性,又不依赖于对象精确的数学模型,且有较强的鲁棒性。论文给出了设计方法及在电加热炉中的应用结果。     

Novel SREKF-based recurrent neural predictor for narrowband/FM interference rejection in GPS

The GPS provides accurate positioning and timing information that is useful in various applications. A new adaptive neural predictor for GPS jamming suppression applications is proposed. The effective and computationally efficient square-root extended Kalman filter (SREKF) algorithm is adopted to adjust the synaptic weights in the nonlinear recurrent architecture and thereby estimate the stationary and non-stationary narrowband/FM waveforms. Cholesky factorization is employed in Riccati recursion to improve numerical stability because of the propagation of round-off errors in conventional KF equations. The main characteristics of the proposed SREKF-based canceller are their rapid convergence and favorable tracking performance. Simulation results reveal that its SNR improvement factor exceeds the factors of conventional LMS, RLS, ENA and TLFN filters in single-tone CWI, multi-tone CWI, pulse CWI and FM jamming environments, respectively.     

A general method to validate breeding value prediction software

The validity of national genetic evaluations depends on the quality of input data, on the model of analysis, and on the correctness of genetic evaluation software. A general strategy was developed to validate national breeding value prediction software: performances from a real data file were replaced with simulated ones, created from simulated fixed and random effects and residuals in such a way that BLUP estimates from the evaluation software must be equal to the simulated effects. This approach was implemented for a multiple-trait model and a random regression test-day model. An example was presented on test-day observations analyzed with a random regression animal model including a lactation curve described as a sum of fixed polynomial regression and fixed spline regression on days in milk, and with genetic and permanent environmental effects modeled by using Legendre polynomials of order 2. Residuals had heterogeneous variances, and phantom parent groups were included. This method can be easily extended to other linear models. The comparison of genetic evaluation results with simulated true effects is used to demonstrate the great efficiency and usefulness of the proposed method.     

VSC-HVDC离散模型及其不平衡控制策略

针对常规控制下电压源换流器(VSC)对交流电网电压不平衡的敏感特性,避免电网电压不平衡引起的直流侧电压二次脉动通过直流线路传播到相邻换流站,该文对VSC进行功率分析并研究其不平衡控制策略。在对VSC进行功率特性分析的基础上,采用了网侧功率节点控制并补偿换流电抗和损耗电阻二倍频功率的不平衡控制策略。同时针对工业现场微机控制器,推导了基于双序矢量电流控制器(DVCC)的离散化内环控制模型、Smith预估补偿器模型和外环控制模型。基于电磁暂态仿真软件PSCAD/EMTDC建立了电压源换流器高压直流输电(VSC-HVDC)离散模型,对外环功率指令阶跃以及两端换流站分别发生电网不平衡故障进行仿真,仿真结论验证了本文离散模型以及不平衡控制策略的有效性。     

Generalized predictor based active disturbance rejection control for non-minimum phase systems

In this paper, a generalized predictor based control scheme is proposed to improve system performance of set-point tracking and disturbance rejection for non-minimum phase (NMP) systems. By using a generalized predictor to estimate the system output without time delay, a model-based extended state observer (MESO) is designed to simultaneously estimate the system state and disturbance. Accordingly, an active disturbance rejection control design is developed which consists of a state feedback control and a feedforward control for the disturbance rejection. The MESO and feedback controllers are analytically derived by specifying the desired characteristic roots of MESO and closed-loop system poles, respectively. To improve the output tracking performance, a pre-filter is designed based on a desired closed-loop transfer function for the set-point tracking. A sufficient condition guaranteeing robust stability of the closed-loop system against time-varying uncertainties is established in terms of linear matrix inequalities (LMIs). Three illustrative examples from the literature are used to demonstrate the effectiveness and merit of the proposed control scheme.