检索结果-内蒙古大学图书馆

1st International IEEE/EMBS Conference on Neural Engineering

作者： Santhanam, G Shenoy, KV Stanford Univ Dept Elect Engn Stanford CA 94305 USA

ISBN: (纸本)0780375793

The prospect of helping disabled patients by translating neural activity from the brain into control signals for prosthetic devices is currently being realized. Initial proof-of-concept systems have demonstrated the need for faster and more accurate estimation algorithms, without requiring unrealistically many neurons. To address this need, we recently reported the plan-movement maximum likelihood (PMML) algorithm. It combines plan activity, specifying reach end-point, with movement activity, specifying instantaneous direction and speed of the arm movement, to yield more accurate estimates with fewer neurons. This approach could greatly benefit from an improved ability to track the switching of plan activity, which precedes movement onset, so that a more accurate plan estimate can be incorporated into movement decoding. In this paper, we propose a modified point-process filter, employing an adaptive parameter, that is capable of more accurately tracking constant plan periods and step changes than conventional methods. We also suggest that this algorithm is more attractive than an alternate maximum likelihood step tracking scheme. Ultimately, the adaptive algorithm is well-suited for use with the PMML algorithm, or for directly controlling prosthetic devices with plan activity, and should improve neural prosthetic system performance.

关键词： neural prosthetic systems estimation algorithms decode algorithms adaptive point-process filters step tracking

来源：评论

学校读者我要写书评

暂无评论

Improving the accuracy of analog encoders via kalman filtering

引用

IFAC Proceedings Volumes 2003年第12期36卷 279-284页

作者： Yaron Zimmerman Amit Brandes Yaakov Oshman Technion - Israel Institute of Technology Faculty of Mechanical Engineering Haifa 32000 Israel University of Rome “La Sapienza” Computer and Systems Science Department Via Eudossiana 1800184 Rome Italy Technion - Israel Institute of Technology Faculty of Aerospace Engineering Haifa 32000 Israel

A new decoding method is presented for linear analog encoders enabling major improvements in both accuracy and resolution. A simulation study is used to demonstrate the performance improvement of the proposed method, demonstrating that the new method can generate position estimates with accuracy about three times better than that of standard methods. Moreover, in some special cases, the resulting position accuracy can reach subnanometer levels, thus enabling further size reduction in the semiconductor industry. The proposed algorithm also yields velocity estimates better by about two orders of magnitude than those obtained with standard methods.

关键词： Encoders Kalman filters estimation algorithms nonlinear filters accuracy measurement noise

来源：评论

学校读者我要写书评

暂无评论

An Approach to Increasing of Safety Operation of Air and Sea Transportation

引用

IFAC Proceedings Volumes 2003年第7期36卷 19-28页

作者： V.Yu. Rutkovsky S.D. Zemlyakov V.M. Sukhanov V.M. Glumov V.A. Trapeznikov Institute of Control Sciences Russian Academy of Sciences Profsoyuznaya 65 117806 Moscow Russia Tel: 007 095 33487 30

A new approach to technical condition monitoring of power units of aircraft and ship engines is suggested. It enables with the help of additional processing of two rotational velocity sensor outputs to get the information about variations of controlled process base parameters. The mathematical model of a transmission of a turboprop aircraft engine is deduced. Synthesis of adaptive algorithm of elastic shaft torsion angle estimation is developed. The task of turbine?s torque identification with the aim engine control improving and (or) for control of fatigue deterioration degree of the shaft?s material is considered. The possibility of the torsion angle adaptive estimation using for look-ahead cut-out of the engine in the case of a dangerous situation leading to destruction of the transportation is considered.

关键词： turbine transmission system of identification estimation algorithms control problems

来源：评论

学校读者我要写书评

暂无评论

On the use of constraints in least squares estimation and control

引用

AUTOMATICA 2002年第7期38卷 1113-1123页

作者： Robertson, DG Lee, JH Georgia Inst Technol Sch Chem Engn Atlanta GA 30332 USA Aspen Technol Global Solut Div Houston TX 77077 USA

In this article, we examine the effect of constraints on estimation and control methods based on quadratic penalty functions. We begin with estimation theory and analyze how constraints alter the statistical properties of the least squares estimates. It is shown that constraints can be used to formulate maximum likelihood (MLE) and maximum a posteriori (MAP) estimators for a variety of unimodal distributions. This provides greater flexibility over the assumption of normality inherent in the MLE and MAP interpretation of traditional least squares. We discuss how these ideas apply to state space models of dynamic systems. Possible applications for controllers that handle constraints are also discussed. A parameter estimation example is given to demonstrate the potential for improved performance over unconstrained least squares. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： optimal estimation non-Gaussian processes constrained parameters estimation algorithms quadratic programming maximum likelihood estimators

来源：评论

学校读者我要写书评

暂无评论

Lyapunov stability and adaptive regulation of a class of nonlinear nonautonomous second-order differential equations

引用

NONLINEAR DYNAMICS 2002年第3-4期28卷 261-272页

作者： de la Sen, M Univ Basque Country Fac Ciencias Inst Invest & Desarrollo Proc IIDP E-48080 Bilbao Spain

This paper presents an adaptive regulation scheme for a class of ordinary nonlinear nonautonomous second-order differential equations which includes as particular cases a number of particular differential equations which occur in applications. The unforced reference model is proposed to be a stable differential parametrization within the general class dealt with. Therefore, some sufficient Lyapunov's stability conditions for such a class are previously investigated which can be used, in particular, to set an appropriate reference model. The resulting closed-loop adaptive scheme is proved to be stable and it involves a parameter estimation scheme of least-squares type which is proved to possess all suitable properties in terms of estimates boundedness and asymptotic convergence of the estimates to finite limits as well as time-integrability of the squared adaptation error.

关键词： adaptive control ordinary nonlinear differential equations estimation algorithms Lyapunov's stability

来源：评论

学校读者我要写书评

暂无评论

Semi-parametric models of long- and short-term survival: an application to the analysis of breast cancer survival in Utah by age and stage

引用

STATISTICS IN MEDICINE 2002年第6期21卷 895-920页

作者： Tsodikov, A Univ Utah Huntsman Canc Inst Div Biostat Salt Lake City UT 84112 USA

A flexible class of semi-parametric survival models is proposed that takes account of long- and short-term covariate effects in cancer survival. The diversity of responses described by the models include non-proportional and crossing survival curves as well as a fraction of long-term survivors. Restricted non-parametric maximum likelihood estimation procedures (RNPMLE) are developed to provide point estimates, confidence intervals and tests for the models. Numerical algorithms to fit semi-parametric survival models are emphasized. The methods are applied to analyse post-treatment survival of breast cancer patients diagnosed in Utah by age and stage. Copyright (C) 2002 John Wiley Sons, Ltd.

关键词： semi-parametric models estimation algorithms age and survival breast cancer

来源：评论

学校读者我要写书评

暂无评论

A DUAL J -LOSSLESS FACTORISATIONS FOR SUBOPTIMAL H ∞ – estimation IN DELTA DOMAIN

引用

IFAC Proceedings Volumes 2002年第1期35卷 31-36页

作者： Piotr Suchomski Technical University of Gdansk WETI-KSA Narutowicza 11/12 80-952 Gdansk Poland

The paper deals with a problem of numerical conditioning of basic J – lossless factori-sations associated with suboptimal H ∞ – norm estimation of discrete-time processes described in the so-called delta-domain. State space formulae for dual J – lossless factorisations of a chain scattering representation of the estimated process are given. Solutions are obtained via solving two coupled algebraic Riccati equations. A relative condition number of the delta-domain algebraic Riccati equation is employed as a measure of numerical conditioning of these solutions. A numerical example is given to show that solutions obtained for the delta operator are much better-conditioned than its counterpart versions based on the common forward shift operator.

关键词： estimation algorithms linear filters numerical algorithms Optimal estimation Riccati equations

来源：评论

学校读者我要写书评

暂无评论

Broad-band measurement and identification of a Wiener-Hammerstein model for an RF amplifier 60

Broad-band measurement and identification of a Wiener-Hammer...

引用

60th Fall ARFTG Conference

作者： Crama, P Rolain, Y Free Univ Brussels Dept TW ELEC B-1050 Brussels Belgium

ISBN: (纸本)0780381246

An RF amplifier under compression is measured using a multi-carrier signal covering the band from 500MHz to 1.5GHz, using the vectorial network analyzer for nonlinear systems (NVNA). Based on this measurement, a Wiener-Hammerstein model for this device is extracted. The model captures the wide band properties of the DUT up to 1.4% error inside the excitation band.

关键词： estimation algorithms identification least-squares identification nonlinear models nonlinear estimation parameter estimation

来源：评论

学校读者我要写书评

暂无评论

Structuring linear transforms for adaptation using training time information

Structuring linear transforms for adaptation using training ...

引用

IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Visweswariah, K Goel, V Gopinath, R IBM Corp Thomas J Watson Res Ctr Yorktown Hts NY 10598 USA

ISBN: (纸本)0780374029

Linear transforms are often used for adaptation to test data in speech recognition systems. However, when used with small amounts of test data, these techniques provide limited improvements if any. This paper proposes a two-step Bayesian approach where a) the transforms lie in a subspace obtained at training time and b) the expansion coefficients of the transform are obtained using MAP. estimation algorithms are given for adaptation transforms for means, covariances, and feature spaces. Experimental results indicate that our method gives a significant improvement in performance over other methods.

关键词： transforms speech recognition Bayes methods feature extraction covariance analysis acoustic signal processing maximum likelihood estimation linear transforms structuring training time information linear transforms test data speech recognition systems two-step Bayesian approach subspace training time expansion coefficients estimation algorithms adaptation transforms mean transforms covariances feature spaces acoustic models maximum likelihood estimation MLE

来源：评论

学校读者我要写书评

暂无评论

FIRST ESTIMATES OF WIENER-HAMMERSTEIN SYSTEMS USING A RANDOM MULTISINE EXCITATION

引用

IFAC Proceedings Volumes 2002年第1期35卷 43-48页

作者： Philippe Crama Johan Schoukens Vrije Universiteit Brussel (Fak. TW-ELEC) Pleinlaan 2 B-1050 Brussel Belgium

Wiener-Hammerstein systems consist of a linear dynamic system followed by a static nonlinearity, followed by another linear dynamic system. These models are difficult to identify due to the presence of two dynamic systems. Usually, a nonlinear estimation procedure is used to estimate the parameters of the different parts. This nonlinear estimation procedure needs good starting values to converge quickly and/or reliably to a global minimum. This paper proposes a method to compute a first estimate based on one measurement record only.

关键词： estimation algorithms identification least-squares identification nonlinear models nonlinear systems parameter estimation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：