一种以太网兼容的综合话音/数据传输协议

本文提出一种与现有以太网兼容的综合话音/数据协议.描述了协议模型及实现方法.并用PASCAL语言在IBM-PC机上模拟研究了该协议的性能.模拟结果表明,该协议能满足话音的实时要求,性能良好,且数据传输性能没有明显下降.协议克服了以太网传输话音延迟不确定的缺点.     

土壤源热泵取热的实验研究

通过广泛分析国内外对土壤源热泵实验研究的现状,建立了可以模拟多个地区、多种运行工况的土壤源热泵沙箱实验台,并进行了绝热边界工况短期内取热的实验研究。     

仿真环境中的网络攻击模型设计

阐述了仿真环境中的网络攻击模型的设计,建立了一个网络攻击仿真模型,用以产生网络攻击,以达到摧毁网络的机密性、完整性和可用性的目的;采用知识表达的方法来建立模型,该模型包含具有知识库和推理机的专家系统,通过随时间而变化的量,使模型具有基于仿真时钟的推理能力;在攻击模型的设计中,定义了它的基本状态和状态跃迁函数,说明了模型的行为,以及攻击策略的制定,最佳策略的选择,攻击选择原则等问题。     

Simulations of the mobile phase of polyethylene

Results are presented from atomistic molecular dynamics simulations of the mobile pseudo-hexagonal phase of polyethylene, which occurs under conditions of elevated pressure and temperature. Three different types of model are considered, all of which employ periodic boundary conditions. The first model consists of n-alkane sequences (48×-C₂₄H₄₈-) that are bonded across the simulation box boundaries to produce chains that are effectively infinite in extent. On heating, at high pressure, this system displays a rotator phase, in which the chains retain an all-trans conformation, and rotate as semi-rigid units. A second model, consisting of finite n-alkanes (48×C₂₄H₅₀) displays the same behaviour at low temperatures, but at high temperature and pressure forms a conformationally disordered rotator phase, characterised by a large proportion of gauche defects and a significant lattice expansion. The final model considered contains long n-alkanes (24×C₁₀₂H₂₀₆) which contain jog defects and each pass twice through the simulation box. This model forms a conformationally disordered rotator phase at high temperature and ambient pressure. The behaviour of the three models, in terms of the variations in chain conformation and rotational and translational dynamics, are compared. The conformationally disordered phases provide useful representations of the experimentally observed mobile phase.     

The Effect of the Estimation on Goodness‐of‐Fit Tests in Time Series Models

Abstract. We analyze, by simulation, the finite‐sample properties of goodness‐of‐fit tests based on residual autocorrelation coefficients (simple and partial) obtained using different estimators frequently used in the analysis of autoregressive moving‐average time‐series models. The estimators considered are unconditional least squares, maximum likelihood and conditional least squares. The results suggest that although the tests based on these estimators are asymptotically equivalent for particular models and parameter values, their sampling properties for samples of the size commonly found in economic applications can differ substantially, because of differences in both finite‐sample estimation efficiencies and residual regeneration methods.     

A framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance

Mechanical mechanisms with clearance abound in technological fields such as robotics, machine and steam turbine industry. The dynamic performance of these mechanisms in working condition can be achieved provided that the effects of the different on the mechanisms (such as mechanism dynamics, technological effects and thermal behaviour) are thoroughly understood. Virtual prototyping provides an integration of multi-domain dynamic simulation for the design and analysis process. In the current paper, a framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance is presented. A case study with such a simulation strategy is studied for the optimum design and analysis of the technological parameter.     

现代数值计算与模拟技术在大学物理中的应用

讨论了现代数值计算与模拟技术在大学物理中的应用，并给出了两个具体应用的实例．     

浅议铵梯炸药质量检验中的三个问题

文章探讨了GB 12437-2000标准规定的产品检验项目中,中包浸水试验的科学性问题和对批产品进行抽样时的样本代表性问题以及使用多段爆速仪测试爆速时应注意的样本量问题.     

提高小样试织质量的措施

介绍了纺织品小样试织时，为了提高试织质量在经纬纱准备及织造工序时所采取的一些措施。