GGSN协议的一个流程问题分析及改进

在网关GPRS(通用无线分组业务)支持节点(GGSN)项目与服务GPRS支持节点(SGSN)项的集成测试中发现了GGSN相关协议的一处流程交互的定义的缺陷,该缺陷导致在异常的流程处理中大量垃圾上下文的生成,并使得GGSN与SGSN两侧信息产生较大的不一致,这些不一致的信息将在较长时间影响系统的后续运行并产生运行错误.本文分析了此流程缺陷产生的原因并对相应流程提出一种改进的方法.实验环境下的测试结果表明,对协议做这样的改进可以完全解决这一问题并保证工程实现的高效性.     

岩土工程开挖模拟的非局部软化模型

基于非线性几何场论，建立了含有天然缺陷的岩土材料非局部连续模型、变分方程及相应的实时更新拖带系大变形有限元数值模型，设计了这一模型的数值卷积算法。对工程材料特别是岩土工程的地下开挖进行的数值结果表明，非局部连续模型描述变形局部化问题是适当的，物性方程包含材料特征尺度对于带缺陷体材料应变软化和损伤的分析是必要的。     

Generalized sparse MRF appearance models

Image segmentation or registration approaches that rely on a local search paradigm (e.g, Active Appearance Models, Active Contours) require an initialization that provides for considerable overlap or a coarse localization of the object to be segmented or localized. In this paper we propose an approach that does not need such an initialization, but localizes anatomical structures in a global manner by formulating the localization task as the solution of a Markov Random Field (MRF).     

数控车削复杂节点计算的一般步骤和方法

为解决数控车削加工编程中节点计算的数学处理方法难点的问题,以一个复杂的节点计算为例,介绍了节点计算的一般规律,同时创新性地采用了高等数学方法来简化节点计算过程,在数控编程中具有借鉴意义。     

节点平差技术在通辽枢纽测量中的应用

结合通辽铁路枢纽布置形式及该地区国家水准点分布情况,在线路水准测量时采用节点平差技术,通过联测不同地方、国家高等级水准点的计算成果,分析偶然中误差超限原因,并进行改正,保证了水准测量精度符合国家标准规范要求。     

现代铜盘管生产工艺、设备及其国产化

介绍当今典型铜管生产工艺，并以工艺流程为线索，介绍主工艺设备的功能、工作原理、特点、发展趋势及其国产化进展。     

戴维宁等效电路参数求解探讨—节点法和网孔法

对含有受控源电路求解戴维宁等效电路，提出了运用节点法和网孔法求解其参数，是一种比较良好的教学方法。     

蒸汽管网运行工况模拟计算方法

论述了蒸汽管网系统运行工况的模拟计算方法，用节点模拟计算法能实现对蒸汽管网系统运行中的流量，压力和温度分布等状况作出总体的模拟计算，论述了蒸汽管网系统节点残量修正计算法的原理，步骤和应用情况。     

Stability region bifurcations of nonlinear autonomous dynamical systems: Type‐zero saddle‐node bifurcations

The behavior of stability regions of nonlinear autonomous dynamical systems subjected to parameter variation is studied in this paper. In particular, the behavior of stability regions and stability boundaries when the system undergoes a type‐zero sadle‐node bifurcation on the stability boundary is investigated in this paper. It is shown that the stability regions suffer drastic changes with parameter variation if type‐zero saddle‐node bifurcations occur on the stability boundary. A complete characterization of these changes in the neighborhood of a type‐zero saddle‐node bifurcation value is presented in this paper. Copyright © 2010 John Wiley & Sons, Ltd.     

A novel method for analyzing dominant oscillation mode based on improved EMD and signal energy algorithm

In this paper,a novel method that integrates the improved empirical mode decomposition(EMD)and signal energy algorithm is proposed to estimate the dominant oscillation parameters and corresponding mode shape.Firstly,the EMD with symmetrical extrema extension(SEE)is utilized to decompose the measured data from wide area measurement system(WAMS)into a finite set of intrinsic mode functions(IMFs).Then,the signal energy algorithm is used to calculate the approximate oscillation parameters of the IMFs.The nodes ...