Implicit integration and consistent tangent modulus of a time‐dependent non‐unified constitutive model

This paper describes the implicit integration and consistent tangent modulus of an inelastic constitutive model with transient and steady strain rates, both of which are time‐ and temperature‐dependent; the transient rate is influenced by the evolution of back stress decomposed into parts, while the steady rate depends only on applied stress and temperature. Such a non‐unified model is useful for high‐temperature structural analysis and is practical owing to the ease in determining material constants. The implicit integration is shown to result in two scalar‐valued coupled equations, and the consistent tangent modulus is derived in a quite versatile form by introducing a set of fourth‐rank constitutive parameters into the discretized evolution rule of back stress. The constitutive model is, then, implemented in a finite element program and applied to a lead‐free solder joint analysis. It is demonstrated that the implicit integration is very accurate if the multilinear kinematic hardening model of Ohno and Wang is employed, and that the consistent tangent modulus certainly affords quadratic convergence to the Newton–Raphson iteration in solving nodal force equilibrium equations. Copyright © 2003 John Wiley & Sons, Ltd.     

基于HMM方法的动态手势轨迹训练性能研究

基于HMM(Hidden Markov Model,隐形马尔可夫模型)对动态手势轨迹的训练是手势识别的关键技术之一。本文对HMM的模型训练采用Baum.Welch算法,并分别从迭代次数,样本个数选取,以及模型初值选取等方面对动态手势轨迹的训练性能进行了研究。实验结果表明HMM方法对具有时空特性的动态手势轨迹识别是非常有效的。     

轴测投影非轴向伸缩系数及与轴测轴的夹角

导出了正轴测图中投影面平行线的伸缩系数及其与轴测投影轴的夹角计算公式,使得各种形状形体的轴测投影画法更简单、尺寸量取更精确.     

应用磷灰石裂变径迹研究大民屯凹陷的古地温

为深刻认识辽河盆地古地温特征，利用裂变径迹分析方法，对大民屯凹陷钻井岩心中19块磷灰石样品的裂变径迹年龄和长度做了测试。结果表明，随井深增加，径迹年龄和平均径迹长度有减少、变短的显著趋势，ES3^4地层磷灰石裂变径迹表观年龄比地层年龄年轻得多，说明沉积后曾长时间处于退火带中，退火带古地温为74～130℃，有效加热时间为4l～45Ma，2300～4000m深度地层处于退火过渡带。将径迹长度分布特征与地史、热史模拟结果相结合，认为该区在ES4段末经历一次短时间迅速增温后，ES3^1亚段存在一个区域抬升降温的热事件过程，其后地层稳定下降，沉降幅度小、沉积物较薄，温度增加缓慢，古地温梯度高于今地温梯度，对生、排烃较为有利。     

大型软件缺陷修正跨国外包后的质量控制

研究了大型软件A93K SOC Series 93000缺陷修正在跨国外包后的质量控制问题,提出了采用缺陷跟踪和缺陷检查的解决方案;并通 过缺陷修正数量和工作流服务质量等指标的分析,论证了CRT(Customer Response Team)质量控制的有效性;得到了综合评价缺陷修正质量控 制成效的一个重要技术指标,即缺陷修正比率FROC(Fixing Rate of CR)。     

时移地震非一致性影响研究与互均衡效果验证

用地震子波对时移地震非一致性造成影响进行了模拟。将影响因素概括为4种形式，即时移、相位变化、振幅量级不一致，频宽不一致。采用互均衡技术对以上4种情况进行校正，达到了理想的效果。为实际资料的处理和方法研究奠定了理论基础。     

A Standard Model-Theoretic Approach to Operational Semantics of Recursive Programs

In this paper we try to introduce a new approach to operational semantics of recursive programsby using ideas in the“priority method”which is a fundamental tool in Recursion Theory.In lieu ofmodelling partial functions by introducing undefined values in a traditional approach,we shall define apriority derivation tree for every term,and by respecting the rule“attacking the subterm of thehighest priority first”we define transition relations,computation sequences etc.directly based on astandard interpretation which includes no undefined value in its domain.Finally,we prove that ournew approach generates the same operational semantics as the traditional one.It is also pointed outthat we can use our strategy to refute a claim of Loeckx and Sieber that the opperational semanticsof recursive programs cannot be built based on predicate logic.     

DNS／GPS组合导航系统研究

本文阐述ＤＮＳ与ＧＰＳ组合导航的必要性、可行性及组合方法，给出了误差模型和卡尔曼滤波模型。选取观测量不同可有三种组合方式，通过模拟计算给出了相应曲线。当采用伪距及其变化率作为观测量时，其组合方式最佳，定位精度可达米级，航向精度可提高到０．２°。     

智能同步广播激励器及其标频

使用智能同步广播激励器,并采用CCTV传输的1MHz标频信号,就有可能实现自适应相位跟踪同步广播。这将大大节省中波段的频率资源。