基于全局背景模型和辅助模型的说话人确认系统的研究

大多数说话人确认系统都设置一个背景模型用于描述假冒者的特性。文中提出一种新的说话人确认背景模型,对所有说话人采用同一全局背景模型（UBM）,并为每个说话人建立一个竞争者模型（cohort model）和一个疏远者模型（c-cohort model）。在全局背景模型不能做出准确判断的情况下,启用竞争者模型或疏远者模型再次进行判决。该模型充分利用了相近者模型和疏远者模型的特性。实验表明新的背景模型使系统性能有明显的提高。     

A general software reliability model for performance prediction

In this paper we give a general Markov process formulation for a software reliability model and present expressions for software performance measures. We discuss a general model and derive the maximum likelihood estimates for the required parameters of this model. The generality of this model is demonstrated by showing that the Jelinski-Moranda model and the Non-Homogeneous Poisson Process (NHPP) model are both very special cases of our model. In this process we also correct some errors in a previous paper of the NHPP model.     

基于空变多项式的高精度重构模型

针对由于合成孔径雷达(SAR)图像几何失真的空变性,传统的多项式模型与距离多普勒模型精度不高的问题,文中提出了结合距离多普勒模型和空变的多项式模型的少量控制点精确重构模型。该模型从距离多普勒方程出发,通过优化地面控制点的方位向分布建立空变的多项式模型,实现SAR图像的高精度重构。实验数据表明:在少量控制点情况下,文中的重构模型精度高于传统的距离多普勒模型和多项式模型。     

Modeling of piezo actuator’s nonlinear and frequency dependent dynamics

To facilitate on-line identification and implementation of a piezoelectric actuator model for precision machining, this paper describes a hybrid hysteresis model integrating the classical Preisach model and a neural network. The incorporation of a neural network enables on-line model identification from operating data of a piezo (a great contrast to the tedious calibration process required by the classical Preisach model). The model is then extended to describe a piezo actuator’s frequency dependent behavior which is not possible for the classical model. Experimental results confirmed the accuracy of both models and the superiority of the extended one.     

基于几何和纹理混合的工业产品三维建模

基于风格化的特征形状或外观样式的三维建模是产品设计客观需求,为此本研究提出了一种基于程序化建模方法的工业产品三维建模软件设计。所述建模方法首先将产品三维模型分割为基础功能模型和样式特征模型,其次搜索基础模型和样式模型的所有可能组合,最后通过采用变形技术将模型在纹理和几何水平上组合。评估结果表明,该建模软件能够输出满足用户感官需求的风格化设计产品,且具有良好的系统性能。     

Model validation and order selection for linear model fitting usingthirdand fourth-order cumulants

Given a linear stationary non-Gaussian signal, suppose that we fit a linear model using higher order statistics and one of several existing methods. The model is fitted under certain assumptions on the data and the underlying (true) model. Having obtained a model, how do we know if the fitted model is “good”? This paper is devoted to the problem of model diagnostics and validation. We propose frequency-domain tests that are applicable to both third- and fourth-order statistics based model fitting unlike existing tests. Model order selection is a byproduct of the model validation approach. Two computer simulation examples are presented to illustrate the proposed tests     

TP model transformation as a way to LMI-based controller design

The main objective of this paper is to propose a numerical controller design methodology. This methodology has two steps. In the first step, tensor product (TP) model transformation is applied, which is capable of transforming a dynamic system model, given over a bounded domain, into TP model form, including polytopic or Takagi-Sugeno model forms. Then, in the second step, Lyapunov's controller design theorems are utilized in the form of linear matrix inequalities (LMIs). The main novelty of this paper is the development of the TP model transformation of the first step. It does not merely transform to TP model form, but it automatically prepares the transformed model to all the specific conditions required by the LMI design. The LMI design can, hence, be immediately executed on the result of the TP model transformation. The secondary objective of this paper is to discuss that representing a dynamic model in TP model form needs to consider the tradeoff between the modeling accuracy and computational complexity. Having a controller with low computational cost is highly desired in many cases of real implementations. The proposed TP model transformation is developed and specialized for finding a complexity minimized model according to a given modeling accuracy. Detailed control design examples are given.     

Maneuvering target tracking by adaptive statistics model

A good model can extract useful information about the target’s state from observations effectively. There are many models used to tracking a, maneuvering target such as constant-velocity (CV) model, Singer acceleration model (zero-mean first-order Markov model) and current model (mean-adaptive acceleration model), etc. While due to the complexity of maneuvering target, to seek the target model which can get better performance is still a subject worthy of study. Based on statistics relation between the autocorrelation function and the covariance of Markov random processing, this paper develops a model which can adaptively adjust system parameters on line. Simulations show the good estimation performance get by the model developed here, and comparing CV, Singer and current models, the model can adaptively get the model parameter while tracking the trajectory and needn’t doing several tests to obtain a priori parameter.     

A unified RLC model for high-speed on-chip interconnects

In this paper, we propose a compact on-chip interconnect model for full-chip simulation. The model consists of two components, a quasi-three-dimensional (3-D) capacitance model and an effective loop inductance model. In the capacitance model, we propose a novel concept of effective width (W/sub eff/) for a 3-D wire, which is derived from an analytical two-dimensional (2-D) model combined with a new analytical "wall-to-wall" model. The effective width provides a physics-based approach to decompose any 3-D structure into a series of 2-D segments, resulting in an efficient and accurate capacitance extraction. In the inductance model, we use an effective loop inductance approach for an analytic and hierarchical model construction. In particular, we show empirically that high-frequency signals (above multi-GHz) propagating through random signal lines can be approximated by a quasi-TEM mode relationship, leading to a simple way to extract the high-frequency inductance from the capacitance of the wire. Finally, the capacitance and inductance models are combined into a unified frequency-dependent RLC model, describing successfully the wide-band characteristics of on-chip interconnects up to 100 GHz. Non-orthogonal wire architecture is also investigated and included in the proposed model.     

Comments on "Some Observations on the Physical Realizability of Compartmental Models with Delays"

A recent communication concluded that a linear differential-difference model presented by Bellman is structurally unrealizable. It is shown here that while the model is indeed unrealizable by a linear compartmental model, it is, in fact, structurally realizable by a linearized nonlinear compartmental model. The potential biological meaningfulness of this result is demonstrated for a simple model of a batch purifier process.     

基于信源、信宿的通信网模型

传统的通信网模型被称为信道和设备的模型,主要体现设备和信道间的关系.其缺点是,在描述一次具体的通信过程时,往往对发送端和接收端没有明确指示.文中在考察了传统通信网模型后,考虑发送端和接收端之间的关系,在原有通信网模型的基础上,引入信源点、信宿点和带方向箭头的边的新通信网模型.在新通信网模型中,明确指出发送端与接收端的关系,建立起"从信源到信宿的通信网模型".     

VARIUS: A Model of Process Variation and Resulting Timing Errors for Microarchitects

Within-die parameter variation poses a major challenge to high-performance microprocessor design, negatively impacting a processor's frequency and leakage power. Addressing this problem, this paper proposes a microarchitecture-aware model for process variation-including both random and systematic effects. The model is specified using a small number of highly intuitive parameters. Using the variation model, this paper also proposes a framework to model timing errors caused by parameter variation. The model yields the failure rate of microarchitectural blocks as a function of clock frequency and the amount of variation. With the combination of the variation model and the error model, we have VARIUS, a comprehensive model that is capable of producing detailed statistics of timing errors as a function of different process parameters and operating conditions. We propose possible applications of VARIUS to microarchitectural research.     

计算机支持多用户协同编著系统模型

文中提出了协同编著系统的基本要求,描述了时间、空间上分散而在任务上又相互依赖的多个作者的交互方式、协作机制,分析了协同编著要素,提出了协同编著系统的逻辑模型,研究了协同编著系统中多用户文档的、操作和并发控制模型,分析了同步会议的管理模型、会议的同步模型和消息的管理策略;最生设计了相应的系统结构模型。     

A novel 3-D scattering model of 1.8-GHz radio propagation inmicrocellular urban environment

This work presents a novel three-dimensional (3-D) scattering model to predict the path loss of a microcellular radio channel in an urban environment. The analytical scattering model combined with a patched-wall model predicts the median path loss more accurately than the conventional analytical ray-tracing model in the cases studied. Comparing the path loss with the measured one at 1.8 GHz demonstrates the effectiveness of the scattering model. The scattering model includes three major propagation modes: (1) a direct-path wave; (2) a ground-reflected wave; and (3) the scattered field from the walls aligned along a street. The proposed model with a polarization scattering matrix associated with the patched-wall model aptly describes the third mode, which is usually neglected or oversimplified     

Differential hysteresis modeling of a shape memory alloy wire actuator

In this paper, we develop a complete mathematical model of a shape memory alloy (SMA) wire actuated by an electric current and a bias spring. The operation of the SMA actuator involves different physical phenomena, such as heat transfer, phase transformation with temperature hysteresis, stress-strain variations and electrical resistance variation accompanying the phase transformation. We model each of these phenomena in a modular fashion. A key feature of the proposed model is that one or more of its modules can be extended to fit other SMA applications. At the heart of the proposed model is a differential hysteresis model capable of representing minor hysteresis loops. We generate the temperature profile for the hysteresis model using lumped parameter analysis. We extend the variable sublayer model to represent actuator strain and electrical resistance. This model can be used to develop a position control system for the actuator. Simulation results from the model are found to be in good agreement with experimental data.     

Intelligent binding in the engineering of automation systems using ontology and Web services

In an integrated automation system a well-designed data model and computation model are required. For the engineering of such a system one often faces a challenge of finding the suitable computation elements defined in the computation model for the data defined in the data model, especially when the data model and the computation model are complex. In this paper we will use the ontology technology and Web services to address the challenge in an intelligent way. We will present the required ontology model including the formal expression, the binding conditions, the object model, XML representation and the corresponding system architecture for implementation. Evaluation is also given to show the usefulness of the approach.     

A Note on Warner''s Vagus Heart Rate Control Model

In the situation of a constant vagus impulse rate, Warner's model for vagal stimulation heart rate (HR) control is a linear differential equation. The particular constants in the Warner model that may be explicitly computed from the experimental data and the sensitivity of the simulation of Warner's model to variations in these parameters are determined. The performance of the Warner model and that of a first-order differential equation model are compared with each other and with experimental data. On the basis of this study, it is concluded that Warner's published experimental data are more supportive of a first-order differential equation model for vagal heart control than it is of a second-order model.     

CRT显示器色度校正的单参数模型

基于Gain-Offset-Gamma(GOG)模型,提出了CRT显示器色度校正的单参数(SP)模型。此模型表达简洁,计算简单,易编程实现。实验中分别采用SP模型和GOG模型测量了CRT显示器色度特性参数,并理论预测了CRT显示器屏幕色。实验结果表明,SP模型预测的阶调复现曲线(TRCs)比GOG模型更符合测量值;对于选用的CRT显示器屏幕色样,GOG模型预测值与测量值的最大色差ΔECIE94为1.57,平均色差为1.11,而SP模型的预测值与测量值的最大色差ΔECIE94为1.06,平均色差为0.618,比GOG模型预测有较小的色差。因此,SP模型将成为最简单、高精度的一种计算机控制CRT显示器颜色表述方法。     

Fitted Elmore delay: a simple and accurate interconnect delay model

In this brief, we present a new interconnect delay model called fitted Elmore delay (FED). FED is generated by approximating HSPICE delay data using a curve fitting technique. The functional form used in curve fitting is derived based on the Elmore delay (ED) model. Thus, our model has all the advantages of the ED model. It has a closed-form expression as simple as the ED model and is extremely efficient to compute. Interconnect optimization with respect to design parameters can also be done as easily as in the ED model. In fact, most previous algorithms and programs based on ED model can use our model without much change. Most importantly, FED is significantly more accurate than the ED model. The maximum error in delay estimation is at most 2% for our model, compared to 8.5% for the scaled ED model. The average error is less than 0.8%. We also show that FED can be more than 10 times more accurate than the ED model when applied to wire sizing.     

SVG与VML的.net模型映射与转化

SVG（Scalable Vector Graphics,可缩放矢量图像）是互联网联盟（W3C）的正式推荐标准,它是一种使用xml来描述二维图像的语言。VML（Vector Markup Language）是一个最初由Microsoft公司开发的xml词表。文中介绍了如何利用.net平台完成SVG模型与VML模型的映射与转化。SVG模型和VML模型处于表示层,加入一个强类型的中间模型,SVG模型到VML模型的映射就可以分解为SVG模型到中间模型的映射和中间模型到VML模型的映射,同时利用.net平台对生成的模型和建立的映射做测试以实现整个项目的准确性。