烷烃在分子筛孔中吸附和扩散的分子模拟

用巨正则系综蒙特卡罗(grand canonical monte carlo,GCMC)和构型偏倚蒙特卡罗(configurational-bias monte carlo,CB- MC)相结合的模拟方法,研究300 K下,烷烃(甲烷、乙烷、丙烷、丁烷)在ISV、MEL型分子筛上的吸附,饱和吸附量的大小顺序为:甲烷>乙烷>丙烷>丁烷。模拟甲烷-乙烷、乙烷-丙烷混合物在分子筛(ISV、MOR、MEL型)中的吸附分离,结果甲烷-丙烷比乙烷-丙烷混合物更易分离。采用分子动力学(molecular dynamics,MD)模拟方法,研究甲烷在MEL、MOR分子筛上的扩散系数,分别为2.76-3.86 m~2·s~(-1)、3.14-13.30 m~2·s~(-1),烷烃在分子筛中的扩散与吸附相关,且扩散系数的大小与分子筛的结构有关。模拟所得的有关吸附扩散性质的数据对于化工生产、研发和设计具有指导意义。     

最小总风险准则的贝叶斯网络个人信用评估模型*

将最小总风险准则MOR与贝叶斯网络分类器相结合,提出了一种新型信用评估模型。在两个真实数据集上以MOR用10层交叉验证对贝叶斯网络信用评估模型进行了测试,并与最小错误概率准则MPE的贝叶斯网络分类器的结果进行了对比。结果表明,基于MOR的贝叶斯网络分类模型可以有效地减小信用评估风险。     

基于LabVIEW的SFP光模块测试平台的设计与实现

介绍了一种利用LabVlEW构建SFP(Small Form-factor Pluggable)光模块测试平台的方法.测试平台通过读写计算机并口来映射地址上的数据,控制并口端口的逻辑电平实现计算机并口模拟I2C总线.计算机利用模拟的I2C总线与SFP光模块实现通信.分析了生产者/消费者结构队列状态机并用于设计中,该设计...     

面向生产管理问题的计算机模拟语言-ECSL

六十年代以来,由于计算机科学和系统科学的发展,出现了一个重要的科学方法——计算机模拟.它在解决一些生产管理、工程技术、科学试验、军事演习和财政经济等同题中,得到了广泛的应用.与此同时也出现了许多专用的计算机模拟语言,如SIMULA(1965,1967年)、GASP(1967年)、GPSS(1967年)、SIMSCRIPT(1968年)等等.这里介绍的是适宜于模拟生产管理问题的计算机模拟语言——ECSL.这对我国借助现代的计算机手段,采用科学方法管理经济无疑会有重要作用.ECSL(Extended Control and Simulation Language)是ESSO石油公司和IBM公司研制的,凡配有FORTRAN语言和具有必要的外部设备的计算机都可以使用.     

调制解调器问与答

问:什么是调制解调器? 答:调制解调器(modem)是一种在计算机与计算机、计算机与数据终端设备之间传输数据信号的设备。它将计算机输出的原始数字信号变换为适应模拟信道传输的信号,这个过程称作调制,实现调制的设备叫调制器。从已调信号恢复调制信号的过程称作解调,相应     

用于测量和控制的计算机系统

相对于通用数字计算机来讲,用于采集和测量的专用计算机的数目并不多。近年来,随着用于输入/输出管理的软件和各种应用程序的发展,它们的数目也有所增加。采集和测量计算机承担的任务是:计算、采集数据、分析数据、仪器控制和过程控制。从硬件的角度讲,采集系统是把一个适当的中央机(PDP-11、HP1000等)与一个专用的I/O设备(模拟的、数字的…)相连接的产物。从软件的角度讲,这种系统能把大量数据以很高     

复杂景观模拟的理论和技术分析

计算机图形学中复杂景观模拟的技术与理论方法,包括对自然客休(规则物体场景及不规则的自然景物)的表达再现和对人为结构(分形结构、数据场的可视化结构等)的构成展示两个方面。它们的共同入处在于对画面质量的要求,如对自然客休的模拟,     

基于OpenGL的人机交互系统设计

人机(计算机)交互(Human-Computer Interaction)系统包括人、计算机输入、输出设备及其相应人机界面(Human-ComputerInterface).本文针对一种笔式三维人机交互系统进行了研究,用二自由度机械跟踪器、DSP数据采集器、蓝牙通信模块、PC机以及研制的界面软件,设计了一种三维人机交互设备,系统能够比较真实的模拟笔在纸面上的运动轨迹,在一定的硬件条件下,系统能够较好地完成实时交互,同时交互过程中能够保证良好的手感.     

地形跟随/地形回避实时仿真系统的设计与实现

为了验证低空突防系统中的地形跟随/地形回避关键技术,设计了一套分布式实时仿真系统。该系统由主控机、地形跟随/地形回避(TF/TA)计算机和视景演示计算机组成。TF/TA计算机采用先进的嵌入式实时操作系统VxWorks进行TF/TA飞行轨迹规划,实时地形匹配,以及模拟雷达的实时数据生成。该系统可以验证算法,模拟飞机在空中飞行的实际效果,为TF/TA系统的试飞验证提供必要准备。     

三值光学计算机模拟器的设计与实现

三值光学计算机(ternary optical computer, TOC)作为一种新体系结构的计算机,具有处理器位数众多且易扩展、位功能可重构、位可分组使用等特点,在海量或复杂数据的快速处理方面有很大潜力,但它的应用开发探索尚处于初期。为了扩展其应用范围,提出了一种基于三值光学计算机体系架构的模拟器TOCSim设计方案。该方案通过软件形式模拟TOC的运行过程,并在普通PC机上实现其雏形。TOCSim主要模拟TOC处理器的重构策略、处理器位的分配策略、中间结果解码以及运算效果模拟等过程。通过本模拟器的模拟效果图与TOC原型机上的运行结果光图进行对比,表明该模拟器的设计方案是正确的、可行的。     

Swarm intelligence algorithm for interconnect model order reduction with sub-block structure preserving

In this paper, we propose a generalised sub-block structure preservation interconnect model order reduction (MOR) technique based on the swarm intelligence method, that is, particle swarm optimisation (PSO). The swarm intelligence-based structure preservation MOR can be used for a standard model as a criterion for different structure preservation interconnect MOR methods. In the proposed technique, the PSO method is used for predicting the unknown elements of structure-preserving reduced-order modelling of interconnect circuits. The prediction is based on minimising the difference of transform function between the original full-order and desired reduced-order systems maintaining the full-order structure in the reduced-order model. The proposed swarm-intelligence-based structure-preserving MOR method is compared with published work on structure preservation MOR SPRIM techniques. Simulation and synthesis results verify the accuracy and validity of the new structure-preserving MOR technique.     

Model Order Reduction for Linear and Nonlinear Systems: A System-Theoretic Perspective

In the past decades, Model Order Reduction (MOR) has demonstrated its robustness and wide applicability for simulating large-scale mathematical models in engineering and the sciences. Recently, MOR has been intensively further developed for increasingly complex dynamical systems. Wide applications of MOR have been found not only in simulation, but also in optimization and control. In this survey paper, we review some popular MOR methods for linear and nonlinear large-scale dynamical systems, mainly used in electrical and control engineering, in computational electromagnetics, as well as in micro- and nano-electro-mechanical systems design. This complements recent surveys on generating reduced-order models for parameter-dependent problems (Benner et al. in 2013; Boyaval et al. in Arch Comput Methods Eng 17(4):435–454, 2010; Rozza et al. Arch Comput Methods Eng 15(3):229–275, 2008) which we do not consider here. Besides reviewing existing methods and the computational techniques needed to implement them, open issues are discussed, and some new results are proposed.     

时域投影模型降阶方法的小样本误差估计

投影方法作为一类重要的模型降阶方法,其计算过程稳定,易于实现,但在理论上鲜有良好的时域误差估计结果．本文提出一种基于小样本估计过程的时域投影模型降阶误差估计方法．该方法首先将降阶过程中产生的误差分解为两部分,然后对各部分利用小样本估计方法进行估计．文中分别对线性和非线性输入输出系统进行小样本误差估计分析．此外,该方法能对线性系统的扰动问题进行分析,进一步的数值算例验证了该方法的有效性．     

基于自适应领域算法的智能照明控制系统

提出一种新型的智能照明控制系统,该系统基于一种新型自适应算法ANA／CC（基于相关性系数的自适应领域算法）,运用最新提出的可视光通信技术在照明设备和照度传感器之间建立直接的通信,从而为特定的地点提供所需要的照度,在整个系统建立的过程中,为该系统建立控制模型。经过实验和仿真发现,该模型可以在短时间内将测试地点的照度达到目标值。     

A method for topology optimization of structures under harmonic excitations

This paper deals with topology optimization of large-scale structures with proportional damping subjected to harmonic excitations. A combined method (CM) of modal superposition with model order reduction (MOR) for harmonic response analysis is introduced. In the method, only the modes corresponding to a frequency range which is a little bigger than that of interest are used for modal superposition, the contribution of unknown higher modes is complemented by a MOR technique. Objective functions are the integral of dynamic compliance of a structure, and that of displacement amplitude of a certain user-defined degree of freedom in the structure, over a range of interested frequencies. The adjoint variable method is applied to analyze sensitivities of objective functions and the accuracy of the sensitivity analyses can also be ensured by CM. Topology optimization procedure is illustrated by three examples. It is shown that the topology optimization based on CM not only remarkably reduce CPU time, but also ensure accuracy of results.     

Model-order reduction for differential-algebraic equation systems with higher index

In this paper, a new model-order reduction (MOR) approach is presented for reducing large-scale differential-algebraic equation (DAE) systems with higher index. This approach is based upon the balanced truncation, single-point, and multi-point MOR methods. We decompose the DAE system into an ordinary differential equation (ODE) subsystem and a DAE subsystem. The DAE subsystem has the same index as the original DAE system. Then, the balanced truncation method is applied to the ODE subsystem. Both single-point and multi-point methods are used to reduce the DAE subsystem. In generally, the multi-point method can perform better than the single-point method across a wide-range of frequencies. Some numerical examples demonstrate the effectiveness of our approach.     

Efficient simulation of hard disk drive operational shock response using model order reduction

The complex structure, coupled mechanical and fluidic energy domains, and inherent nonlinearity of air bearing between slider and disk involved in the hard disk drive (HDD) are normally presented as a large scale problem which will result in very heavy computational costs in terms of intensive computation and time consuming for HDD research communities and industries to carry out the transient dynamic simulation for HDD design verification, performance analysis, and optimization by using the traditional full-order models, such as finite element model (FEM). This paper presents a method of application of model order reduction (MOR) technique to dramatically reduce the computation time for HDD transient shock performance analysis while capturing the behaviors of original problem faithfully. The reduced models are obtained by performing MOR directly to the FEMs through Krylov subspace and Arnoldi algorithm. The transient operational shock response results of the reduced models of a head suspension assembly (HSA) subjected to half-sine shock pulse demonstrate that the reduced models can dramatically reduce total computation by at least three orders and have very good agreement with those simulated from the original large problem by full-order FEM.     

Piecewise Polynomial Model Reduction Method for Nonlinear Systems in Time Domain

Model order reduction (MOR) of nonlinear systems draws great attention in the past several decades. This paper presents a new MOR method in time domain for nonlinear dynamical systems. The new algorithm is based on the combination of the Taylor series expansion for the state variable x(t) and the trajectory piecewise polynomial technique. Firstly, the nonlinear system is approximated by a piecewise polynomial representation. Then, based on the Taylor series coefficients of x(t), we formulate the projection matrix V for the piecewise polynomial system and the compact model of the piecewise polynomial system is obtained in the following. Besides, error estimation and stability analysis are also presented in this paper. Finally, two nonlinear systems are tested to verify the effectiveness of the algorithm.     

H2 optimal model order reduction by two-sided technique on Grassmann manifold via the cross-gramian of bilinear systems

In this paper, we discuss the optimal H₂ model order reduction (MOR) problem for bilinear systems. The H₂ optimal MOR problem of bilinear systems is considered as the minimisation problem on Grassmann manifold, which is stored as a quotient space of the noncompact Stifiel manifold. Grassmann manifold whose tangent space is endowed with a Riemannian metric is a Riemannian manifold. In its tangent space equipped with the Riemannian metric, we derive the negative gradients of the cost function, i.e. the steepest descent direction of the cost function. After that, the formulas of geodesic on Grassmann manifold are given. Then we perform linear searches along geodesics to obtain the optimal solutions. Thereby, a two-sided MOR iterative algorithm is proposed to construct an order-reduced bilinear system, which is used to simulate the output and input responses of the original bilinear system. Numerical examples demonstrate the effectiveness of our algorithm.