光电设备电子机柜布线工艺研究

作为信号和电能载体的导线，同时也是噪声的载体和外来噪声侵入设备的媒体。描述了噪声通过导线侵入设备内部的方式，通过降低噪声的途径确定了机柜布线的原则，介绍了布线的要求和方法，最后提出了用布线槽布线的建议。     

High Accuracy Analysis of the Adini's Nonconforming Element

Received September 14, 2000; revised September 25, 2001     

Partitioned half-explicit Runge-Kutta methods for differential-algebraic systems of index 2

A class of half-explicit methods for index 2 differential-algebraic systems in Hessenberg form is proposed, which takes advantage of the partitioned structure of such problems. For this family of methods, which we call partitioned half-explicit Runge-Kutta methods, a better choice in the parameters of the method than for previously available half-explicit Runge-Kutta methods can be made. In particular we construct a family of 6-stage methods of order 5, and determine its parameters (based on the coefficients of the successful explicit Runge-Kutta method DOPRI5) in order to optimize the local error coefficients. Numerical experiments demonstrate the efficiency of this method for the solution of constrained multi-body systems.     

Parallel integration of ODEs based on convolution algorithms

We consider parallel computing methods for ODEs based on the potential parallelism of convolution algorithms. Detailed presentations of fast convolution algorithms are provided. Implementations of our methods on signal processors and special processors are described. The main emphasis is concentrated on applications of powerful parallel signal processing facilities in ODE computations. By using convolution algorithms we show some treatments of parallel computing in finite fields. As an example of our approach we discuss integrating Lorenz's model.

---

Zusammenfassung Wir behandeln parallele numerische Methoden für gewöhnliche Differentiagleichungen, die auf Parallelismus von konvolutiven Algorithmen basieren. Ausführliche Darstellungen der schnellen konvolutiven Berechnungen mit spezieller Hardware werden präsentiert. Der Schwerpunkt dieser Arbeit ist die Anwendung von leistungsfähigen parallelen Signal-Prozessoren in der Berechnung gewöhnlicher Differentialgleichungen. Unter Verwendung von Konvolutiven Algorithmen erläutern wir einige Anwendungen von parallelem Rechnen in endlichen Körpern. Als Beispiel unseres Zugangs diskutieren wir die Integration des Lorenz-Modells.

     

Viscous flow past a porous sphere with an impermeable core : effect of stress jump condition

An arbitrary flow of a viscous, incompressible fluid past a porous sphere of radius `a' with an impermeable core of radius `b', using Brinkman's equation in the porous region is discussed. At the interface of the clear fluid and porous region, stress jump boundary condition for the tangential stresses along with the continuity of normal stresses and the velocity components are used. On the surface of the impermeable core no slip condition is used. The corresponding Faxen's laws are derived to compute the drag and torque acting on the surface r=a. It is found that the drag and torque not only change with the change of the permeability, but also a significant effect of the stress jump co-efficient is observed. The variation of drag and torque with permeability for different thickness (a-b) of the porous region as well as for different values of stress jump coefficient is discussed when the basic flow is due to uniform flow, two dimensional irrotational flow, doublet in a uniform flow, stokeslet, rotlet. In case of uniform flow the flow field has been plotted. In all the cases, a significant effect of the stress jump coefficient has been realized.     

Parameter Estimation for Periodically Stationary Time Series

Abstract. The innovations algorithm can be used to obtain parameter estimates for periodically stationary time series models. In this paper, we compute the asymptotic distribution for these estimates in the case, where the innovations have a finite fourth moment. These asymptotic results are useful to determine which model parameters are significant. In the process, we also develop asymptotics for the Yule–Walker estimates.     

An LMI approach to synthesis subject to almost asymptotic regulation constraints

A multi-objective controller synthesis problem is considered in which an output is to be regulated approximately by assuring a bound on the steady-state peak amplification in response to an infinite-energy disturbance, while also guaranteeing a desired level of performance measured in terms of the worst-case energy gain from a finite-energy input to a performance output. Relying on a characterization of the controllers with which almost asymptotic regulation is accomplished, the problem of guaranteeing the desired level of performance is reduced to solving a system of linear matrix inequalities subject to a set of linear equality constraints. Based on the solution of this system, a procedure is outlined for the construction of a suitable controller whose order is equal to the order of the plant plus the order of the exogenous system.     

control with limited communication and message losses

We propose an H^∞ approach to a remote control problem where the communication is constrained due to the use of a shared channel. The controller employs a periodic time sequencing scheme for message transmissions from multiple sensors and to multiple actuators of the system. It further takes into account the information on the random message losses that occur in the channel. An exact characterization for controller synthesis is obtained and is stated in terms of linear matrix inequalities. Furthermore, an analysis on the loss probabilities of the messages to accomplish stabilization is carried out. The results are illustrated through a numerical example.     

Estimation of parameters of the Makeham distribution using the least squares method

The Makeham distribution has been used to describe human mortality and establish actuarial tables. The hazard function is defined by μ(t)=A+BC^t$\mu (t)=A+B{C}^t$, we use the least squares type estimation to estimate the parameters of Makeham distribution in this paper. Seven cases are considered, when A, B, C are known or unknown, respectively. Also, we evaluated the mean square errors of these estimators.     

用ZigBee技术实现安防系统中部分子系统的无线通信

安防系统中除视频监控系统之外的其他子系统对传输速率的要求井不高,ZigBee无线网络技术具有低功耗、低速率、低成本等特点,把ZigBee技术应用到安防系统的部分子系统中,能够实现其无线信息传输,既避免布线又节约成本.