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。     

Semiparametric Estimation in Time‐Series Regression with Long‐Range Dependence

Abstract. We consider semiparametric estimation in time‐series regression in the presence of long‐range dependence in both the errors and the stochastic regressors. A central limit theorem is established for a class of semiparametric frequency domain‐weighted least squares estimates, which includes both narrow‐band ordinary least squares and narrow‐band generalized least squares as special cases. The estimates are semiparametric in the sense that focus is on the neighbourhood of the origin, and only periodogram ordinates in a degenerating band around the origin are used. This setting differs from earlier studies on time‐series regression with long‐range dependence, where a fully parametric approach has been employed. The generalized least squares estimate is infeasible when the degree of long‐range dependence is unknown and must be estimated in an initial step. In that case, we show that a feasible estimate which has the same asymptotic properties as the infeasible estimate, exists. By Monte Carlo simulation, we evaluate the finite‐sample performance of the generalized least squares estimate and the feasible estimate.     

High Accuracy Analysis of the Adini's Nonconforming Element

Received September 14, 2000; revised September 25, 2001     

EILog-05成套测井装备在长庆油田的应用

EILog-05成套测井装备是中国石油集团测井有限公司研发的具有完全自主知识产权的集成测井系统。集成化设计提高了测井仪器性能,综合化设计实现了地面系统网络化,成像测井仪器的配接成功丰富了测井项目,配套使用的一体化LEAD处理解释软件能更好地实现测井资料的现场综合解释。20井次现场试验、与ECLIPS-5700测井系统5口井的对比试验以及累计300多井次的现场应用表明,EILog-05成套测井装备的可靠性、稳定性、重复性以及与国外同类仪器测井结果的一致性均满足油田生产需要,能很好地判断长庆油田的“三低一高”复杂地层,对认识岩石三性关系和评价油气显示具有重要的作用。     

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.

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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.

     

Efficient and optimal exponentiation in finite fields

Optimal sequential and parallel algorithms for exponentiation in a finite field containing F _q are presented, assuming thatqth powers can be computed for free.     

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.