元胞自动化与软计算的集成及其应用

介绍了元胞自动机的思想来源和基本原理，对元胞自动机与软计算的人工智能技术进行比较并加以集成，讨论了近年来它在混沌分形，图像处理，智能材料，机器学习，模拟复杂现象等领域中的应用成果，并对进一步研究进展展望。     

细观元胞自动机与三分子反应模拟

为了刻划多组分宏观系统中粒子间的复杂且随机的局部相互作用,作者打破现有元胞自动机的局限,借用粗粒化的思想,将多个状态变量引入随机元胞自动机,提出了称之为“细观元胞自动机”的一种扩展的元胞自动机概念模型,然后将该模型应用于Ｂｒｕｓｓｅｌａｔｏｒ的计算机模拟,制定了４组分系统中粒子的随机运动和反应碰撞等的演化规则,建立了三分子反应的二维地胞自动机模型,并在计算机上对该模型成功地进行了动态模拟。     

元胞自动机与软计算的集成及其应用

介绍了元胞自动机的思想来源和基本原理，对元胞自动机与敦计算的人工智能技术进行比较并加以集成，讨论了近年来它在混沌分形、图像处理、智能材料、机器学习、模拟复杂现象等领域中的应用成果，并对进一步研究进行展望。     

基于元胞自动机的交通流计算机模拟

元胞自动机是把复杂系统量化为简单的个体,在元胞自动机模型中.空间、时间都被离散化,每一个相互作用的单元仅为有限的状态.以元胞自动机理论为基础,把车辆在路段上交通流中运动的变化规律表述为元胞自动机的演化规则,建立了基于元胞自动机理论的交通流模拟模型,标定了元胞长度和最大速度等参数,分析了元胞变换的原则;详细探讨了元胞自动机在道路交通模拟中的应用,设计出了交通元胞自动机的结构,分析了交通元胞自动机所采取的状态变换原则,建立了一维(单车道)交通流模拟模型;并利用C语言编程实现模拟.模拟结果符合实际交通流的特点.     

面向对象的有限空间内人群流动CA模型研究

为了模拟在有限空间中大量人员的流动分布，基于面向对象技术，在已有交通流模型和行人流模型的基础上，建立了一个在有限空间内高密度人群流动的元胞自动机模型。采用面向对象思想的建模方法，使得模型具有很好的适用性、扩展性和复用性。并根据出现高密度人群的一般情况和控制对象的需求，提出“元胞控制块”的概念，使整个模型架构具有很强的应用转化能力。计算机模拟验证的结果良好，充分显示了元胞自动机模型对复杂人群流动的模拟能力。     

自组织现象的元胞自动机模拟与图示

将确定性元胞自动机、随机元胞自动机、及作者创建的多元随机元胞自动机，用于模拟自然界广泛存在的自组织现象。建立了若干自组织行为的元胞自动机模型，并用自己编制的ＰＣＷｉｎｄｏｗｓ环境下的通用元胞自动机程序，模拟ＢＺ振荡反应、定向压力下结晶条带形成、天分子化学反应等自组织过程。最后对该程序的工作平台及主要的模拟与功能作了简单的说明。     

初等元胞自动机的界面设计及稳定性分析

建立了所有规则下的初等元胞自动机的可视化模型及界面,设计了用于判断初等元胞自动机稳定性的应用程序,并可直接计算得到演化类型及周期.在此基础上,模拟得到了不同元胞数m,随机产生的不同的初始状态,不同规则数R以及各种边界条件下初等元胞自动机的演化结果,并分析了以上因素对稳定性的影响.结果表明:元胞数m,初始状态,规则数R以及边界条件,均对初等元胞自动机的演化类型,演化周期产生较大影响.充分反映了元胞自动机的复杂性.模型从模拟的角度出发,为元胞自动机的复杂性研究提供了一个简单的、可视的计算机仿真工具,并可为复杂的理论推导提供参考或验证.     

元胞自动机可逆性研究

元胞自动机是对复杂适应系统建模的重要理论工具。可逆性是元胞自动机的一个重要属性,是模拟物理可逆空间的必要条件。本文介绍元胞自动机的基本概念、可逆性和可计算性,并介绍一维可逆元胞自动机可计算的证明思路。     

交通元胞自动机计算机模拟模型的研究

主要介绍了元胞自动机的基本理论,分析了元胞变换的原则;详细探讨了元胞自动机在道路交通模拟中的应用,设计出了交通元胞自动机的结构,分析了交通元胞自动机所采取的状态变换原则,建立了一维（单车道）交通流模拟模型;论述了元胞自动机的发展及在道路交通模拟中的研究前景。     

Liesegang环带的形成机理及其元胞自动机模拟

提出了一种在反应沉淀过程中过饱和成核结晶加上Ostwald熟化作用的Liesegang环带形成机理 ,并按此机理建立了一种二维混合随机元胞自动机模型 ,制定了成核、结晶、溶解、分解、迁移、反应和扩散等的演化规则 ,并在计算机上对该Liesegang环带的元胞自动机模型进行了动态模拟     

Verification of Cache Coherence Protocols by Aggregation of Distributed Transactions

This paper presents a method to verify the correctness of protocols and distributed algorithms. The method compares a state graph of the implementation with a specification which is a state graph representing the desired abstract behavior. The steps in the specification correspond to atomic transactions, which are not atomic in the implementation. The method relies on an aggregation function, which is a type of abstraction function that aggregates the steps of each transaction in the implementation into a single atomic transaction in the specification. The key idea in defining the aggregation function is that it must complete atomic transactions which have committed but are not finished. This paper illustrates the method on a directory-based cache coherence protocol developed for the Stanford FLASH multiprocessor. The coherence protocol consisting of more than a hundred different kinds of implementation steps has been reduced to a specification with six kinds of atomic transactions. Based on the reduced behavior, it is very easy to prove crucial properties of the protocol including data consistency of cached copies at the user level. This is the first correctness proof verified by a theorem-prover for a cache coherence protocol of this complexity. The aggregation method is also used to prove that the reduced protocol satisfies a desired memory consistency model. Received October 1996, and in final form August 1997.     

组合对Ag-Rh双金属团簇熔化行为的影响

采用分子动力学方法,模拟研究了6种不同组合、具有正十面体壳对称构型、原子总数为魔幻数(309)的Ag-Rh双金属团簇的熔化过程。研究金属原子间作用力采用Sutton-Chen多体作用势能模型,初始构象取自半巨正则系综Monte Carlo模拟结果。通过分析模拟所得到的平均单原子势能Ua和等容热容Cv与温度的关系,得出各团簇的熔点,还发现Ag-Rh双金属团簇熔点与团簇中Ag原子数的增加呈近似线性相关。     

MATLAB平台上的DLCA过程模拟

在MATLAB平台上构建了粒子聚集过程的模拟软件。软件包括主控台模块、参数设置模块、行走模块、分析模块，每一模块又包含数个功能子模块，根据需要调用部分或全部模块。该软件可对含有10万个粒子的大型体系进行模拟。文中分别对模拟得到的聚集速率、粒度分布、聚集体结构进行了讨论。     

Automatic classification of clustered microcalcifications by a multiple expert system

Mammography is a not invasive diagnostic technique widely used for early cancer detection in women breast. A significant visual clue of the disease is the presence of clusters of microcalcifications. The automatic recognition of malignant clusters of microcalcifications, which could be very helpful for diagnostic purposes, is a very difficult task because of the small size of the microcalcifications and of the poor quality of the mammographic images.In this paper we propose a novel approach for classifying clusters of microcalcifications, based on a Multiple Expert System; such system aggregates several experts, some of which are devoted to classify the single microcalcifications while others are aimed to classify the cluster considered as a whole. The final output results from the suitable combination of the two groups of experts. The tests performed on a standard database of 40 mammographic images have confirmed the effectiveness of the approach.     

Objective quantification of acetylcholine receptor aggregation using fast Fourier transforms

A new approach for objectively analyzing the aggregation of acetylcholine receptors (AChRs) through power spectrum analysis derived from fast Fourier transform (FFT) of images has been developed. Presently, detection of AChR aggregates at neuromuscular junctions is not easily accomplished. Though the formation of AChR clusters results in periodic gray-level variations that differ with time, no study reporting their correlation with frequency information in the Fourier domain for aggregates' detection purposes exists. To this end, we processed time-lapse images of AChR aggregates' formation on murine myotubes to extract peak values of power spectra. To validate interpretation of the Fourier spectra analysis, a computer routine was developed to semi-automatically count AChR aggregates. We found: (1) logarithmic maxima of Fourier spectra correlated significantly with experimentation time; (2) cluster count correlated significantly with time only after clusters were discernable from images, signifying that this method heavily depended on definitive growth data and thresholding values; (3) exponents of Fourier maxima versus time and cluster count versus time profiles during this phase compared favorably, indicating that both methods were analyzing identical cluster growth rates. Our observations suggest that analysis via FFT power spectrum is sensitive and robust enough to automatically quantify AChR aggregates.     

基于神经网络和遗传算法的悬挂系统优化设计

悬挂系统具有复杂的机械结构,对于这种非线性系统进行优化设计难度较大,且采用计算机仿真反复试验耗时巨大;基于神经网络和遗传算法,利用机械系统动力学仿真软件MSC＼ADAMS中的ATV模块,对悬挂系统中影响自行火炮行驶平稳性的各参数进行优化,取得了较好的结果,证明了该技术路线的可行性。     

Formation energies of CdSe wurtzoid and diamondoid clusters formed from Cd and Se atomic clusters

Cadmium Selenide thermodynamic formation energies at the molecular and nanoscale range are investigated using density functional theory. The investigation is performed using wurtzoid and diamondoid clusters that represent the wurtzite and zincblende structures at the molecular and nanoscale size range for a cluster number of atoms n ≤ 26. Cd and Se atomic clusters are optimized and used to provide component atomic cluster energies. Although both Cd and Se clusters at the nanoscale have different phases than bulk, the results show that Gibbs free energy, enthalpy, and entropy of formation of CdSe are close to their experimental bulk energies of formation within errors of experimental measurements. CdSe wurtzoids generally have higher absolute (more negative) Gibbs free energy of formation than CdSe diamondoids indicating more stable wurtzoid molecules which is also the case at bulk. The absolute Gibbs free energy of wurtzoids is also higher than experimental value (more negative) because of surface effects at the nanoscale. Enthalpy of formation indicates an exothermic reaction of Cd and Se clusters as is the case at bulk. The entropy of formation of all clusters is size-sensitive and converges towards bulk experimental measurements. Both wurtzoids and diamondoids members contain Cd₁₃Se₁₃ cluster which is the most investigated magic CdSe cluster.     

Data structure for on-lattice cluster–cluster aggregation model performance optimization

A compounded data structure is developed to optimize the simulation of colloidal aggregation using the on-lattice Cluster–Cluster Aggregation (CCA) model. Brownian motion, collision detection and aggregation as the basic operations in the CCA simulation are illustrated and evaluated based on the compounded data structure, respectively. The critical improvement of our algorithm is in distinguishing any selected clusters consisting particles and ascertaining their neighboring positions efficiently in simulation, which was traditionally performed by the exhaustive search in the whole system. Analytical results show that the new algorithm achieves linear computational complexity in each of the main operations, which is very appealing in performance optimization in using on-lattice CCA simulations.     

进排气调压系统半物理仿真程序的设计与实现

半物理仿真是仿真领域研究的热点和难点,在研究系统性能和控制策略时非常有用;为构建一个实时性较强的进排气调压半物理仿真系统,结合高空台调压系统的特点,提出了上位机、下位机+实物部件的形式组成半物理仿真系统,在上位机开发了仿真程序,基于PLC(Programmable Logic Controller)开发了此系统的下位机程序;实现了模型计算、数据采集、上下位机数据通讯及系统参数控制等功能;仿真试验表明,该系统的上下位机程序具有很好的实时性、精确性和稳定性。