基于元胞自动机模型的图像分割算法

针对图像处理中的图像分割任务,我们提出了一个基于模糊元胞自动机模型的图像分割算法.将元胞自动机原理中的演化规则换为模糊规则建立模糊元胞自动机模型,使图像中灰度水平介于目标和背景之间的像素得以更好地归类,从而得到较好的图像分割结果.     

基于元胞自动机的SARS传播模型

根据SARS的局部性、潜伏性特征以及传染病个体传播的特点,人群接触通过近距离邻居发生,利用元胞自动机模型时间、空间上离散,以局部规则为基础,以同步更新为前提讨论整体性质的机制,将人群分为易感者,带菌者,病人,免疫者之后,以易感者对SARS的抵抗能力、病人或带菌者对SARS的传染能力、人群的大小为参数,建立了基于元胞自动机的SARS传播模型.得到的结果可为从传染动力学角度控制SARS的传播提供依据.     

建立在模糊逻辑上的模糊元胞自动机

总结了经典元胞自动机模型理论,并在此基础上把模糊逻辑引入元胞自动机模型中.通过对模糊元胞自动机的基本原理的分析,定义了模糊元胞自动机模型.模糊元胞自动机模型可以处理模糊信息,并且使模拟与现实世界的情况更为接近.     

基于元胞自动机的供需网企业合作驱动建模与仿真

针对供需网企业合作驱动具有一定的复杂性这一现状,基于元胞自动机模型对三种状态的节点交互及供需网系统合作演变过程进行仿真,探讨了不同驱动作用下供需网企业合作行为的演化趋势。研究结果表明:供需网企业合作行为演化存在供需质交互频率阈值,当交互频率大于该阈值时,企业合作数量较高且会稳定在某一水平;提高企业的多功能合作执行力、外部力量等可以增加企业合作规模和数量,进而可以促进合作子系统的形成和合作平台的构建。     

场馆人员疏散的元胞自动机模拟

在人口密集场所(馆)观众席位区及疏散通道分布模拟图的基础上,应用数据库技术结合元胞自动机模拟了场馆中人员的疏散情况,并针对场馆发生突发事件后,在疏散过程中某个出口堵塞的情形进行了模拟,模拟结果可以记录人员疏散的轨迹,为突发事件发生后人员疏散应急方案提供参考.     

基于元胞自动机的交叉口混合交通模型研究

在我国很多中小城市普遍存在着摩托车与小汽车混行的现象,摩托车既有类似自行车横向移动灵活、启动速度快的特点,又有类似小汽车纵向移动速度快的特点,特别是在城市交叉口附近范围内,摩托车与小汽车几乎速度相当.根据交叉口红灯起亮时,摩托车会灵活穿插,充分利用车道空间,绿灯起亮时,由于摩托车的启动速度比小汽车快,产生侧向膨胀效应,挤压小汽车行驶空间,从而使其速度减慢等现象,结合我国中小城市交叉口小汽车及摩托车的行驶特性,利用元胞自动机模型,建立信号交叉口小汽车与摩托车的混合交通模型.     

基于二型模糊逻辑的元胞自动机模型

将二型模糊逻辑推理引入到元胞自动机模型中,把二型模糊逻辑推理与经典的元胞自动机模型结合起来,建立一种新的推理演化模型,基于二型模糊逻辑的元胞自动机模型.元胞自动机模型的关键部分是演化规则和元胞状态.将元胞自动机模型中的演化规则二型模糊化,将经典元胞自动机模型中的元胞状态模糊化为二型模糊状态,建立基于二型模糊逻辑的元胞自动机模型.     

22号初等元胞自动机的演化复杂性

Cellular automata are the discrete dynamical systems of simple construction but with complex and varied behaviors. In this paper, the elementary cellular automaton of rule 22 is studied by the tools of formal language theory and symbolic dynamics. Its temporal evolution orbits are coarse-grained into evolution sequences and the evolution languages are defined. It is proved that for every n≥2 its width n evolution language is not regular.     

基于跟车思想的一维元胞自动机交通流模型

提出一个改进的一维元胞自动机模型来模拟周期性边界条件下高速公路上车流运动.基于跟车模型的思想,根据所研究车辆与其前方紧邻车辆之间的间距和相对速度来确定该车的运动,间接地反映了次近邻车辆的影响.通过引入安全间距来描述高速运动车辆接近前方缓行车辆时的减速行为,并利用随机减速概率来反映减速行为中的随机因素.由于安全间距的引入,当减速概率大于零时在较高密度下就出现完全的阻塞相.同时在本模型中采用的是有条件减速,因而可以较好描述交通实测中观察到的现象.在临界密度附近,车流运动处于亚稳态并呈现出滞后现象.由于本模型对于车辆微观运动的合理描述,可以直接用以研究在交通灯控制下城市道路交通中的各种现象.     

随机化交通灯的二维元胞自动机交通模型

元胞自动机交通模型以简单的规则反映交通系统中的多种因素，可以分析各种交通现象，且可在计算机上方便、高效地运作·Ｂｉｈａｍ－Ｍｉｄｄｌｅｔｏｎ－Ｌｅｖｉｎｅ模型（ＢＭＬ模型）实现了二维交通问题的元胞自动机模型的模拟研究·本文对ＢＭＬ模型作了改进，解除了该模型中关于交通灯同步变化的限制·在新模型中，每个路口的交通灯可以自由选定起始工作时间和变化节奏，于是可以更全面、准确地反映交通灯对交通系统性能的影响·本文还对新模型中出现的若干新效应作了解释·     

Control parameters in Boolean networks and cellular automata revisited from a logical and a sociological point of view

The use of “control parameters” as applied to describe the dynamics of complex mathematical systems within models of real social systems is discussed. Whereas single control parameters cannot sufficiently characterize the dynamics of such systems it is suggested that domains of values of certain sets of parameters are appropriately denoting necessary conditions for highly disordered dynamics of social systems. Various of those control parameters permit a straightforward interpretation in terms of properties of social rules and structures. © 1999 John Wiley & Sons, Inc.     

Three-dimensional cellular automaton simulation of tumour growth in inhomogeneous oxygen environment

Cellular automaton theory has previously been used to study cell growth. In this study, we present a three-dimensional cellular automaton model performing the growth simulation of normal and cancerous cells. The necessary nutrient supply is provided by an artificial arterial tree which is generated by constrained constructive optimization. Spatial oxygen diffusion is approximated again by a cellular automaton model. All results could be illustrated dynamically by three-dimensional volume visualization. Because of the chosen modelling approach, an extension of the model to simulate angiogenic processes is possible.     

眼科病床配置的优化模型及其计算机模拟

为了实现资源的高效利用,采用排队论思想,建立了眼科病床合理配置的优化模型,并用计算机模拟的方法对模型进行了检验,根据历史数据,求得五类病人被分配到的病床比例为19%、24%、21%、10%、26%,所得结果与实际吻合较好,优化模型对病床的合理配置具有一定的借鉴意义.     

制度下行为模拟的Agent与CA方法比较研究

在对CAS理论研究的基础上,分析了基于其理论框架下相对成熟且应用较为广泛的两种行为模拟模型或方法(即智能体和元胞自动机),并对它们的优缺点及适用领域进行了比较,对其发展趋势和前景进行了展望.     

慢性病发病率置信区间的构造

在流行病研究中,发病率是一个重要指标,该指标反映的是特定人群中某种疾病的发病程度.因此,对它的置信区间的构造在判别疾病发病程度上具有重要的医学意义.对于一些慢性疾(如癌症或心血管等),由于其发病周期长,发病率低,Poisson抽样下要比二项抽样,逆项抽样更符合事实.利用四种方法研究了泊松分布下慢性病发病率的置信区间构造,并通过Monte Ca·lo模拟对四种方法的表现性能进行比较.模拟结果表明:当发病率较高时,枢轴量方法无论在区间长度还是覆盖率上都袁现最佳:当发病率相对较低时,枢轴量方法在区间长度上略次于Wald统计量方法和得分方法,但是在覆盖率上袁现最佳.因此,枢轴量方法整体上表现的很好.     

Instrumenting Mathematical Activity: Reflections on Key Studies of the Educational Use of Computer Algebra Systems

This paper examines the process through which students learn to make functional use of computer algebra systems (CAS), and the interaction between that process and the wider mathematical development of students. The result of ‘instrumentalising‘ a device to become a mathematical tool and correspondingly ‘instrumenting’ mathematical activity through use of that tool is not only to extend students' mathematical technique but to shape their sense of the mathematical entities involved. These ideas have been developed within a French programme of research – as reported by Artigue in this issue of the journal – which has explored the integration of CAS – typically in the form of symbolic calculators – into the everyday practice of mathematics classrooms. The French research –influenced by socio-psychological theorisation of the development of conceptual systems- seeks to take account of the cultural and cognitive facets of these issues, noting how mathematical norms – or their absence – shape the mental schemes which students form as they appropriate CAS as tools. Instrumenting graphic and symbolic reasoning through using CAS influences the range and form of the tasks and techniques experienced by students, and so the resources available for more explicit codification and theorisation of such reasoning. This illuminates an influential North American study– conducted by Heid – which French researchers have seen as taking a contrasting view of the part played by technical activity in developing conceptual understanding. Reconsidered from this perspective, it appears that while teaching approaches which ‘resequence skills and concepts’ indeed defer – and diminish –attention to routinised skills, the tasks introduced in their place depend on another –albeit less strongly codified – system of techniques, supporting more extensive and active theorisation. The French research high lights important challenges which arise in instrumenting classroom mathematical activity and correspondingly instrumentalising CAS. In particular, it reveals fundamental constraints on human-machine interaction which may limit the capacity of the present generation of CAS to scaffold the mathematical thinking and learning of students. This revised version was published online in July 2006 with corrections to the Cover Date.     

信息与计算科学专业应用型人才培养模式的研究

分析了信息与计算科学专业课程教学的特点和存在的教与学的矛盾.并以《高等代数》为试点,在教学实践中试行教学改革,积极探索教学与实际相结合与计算机信息有机结合的教学模式,在应用型人才培养方面取得显著成效.对信息与计算科学专业应用型人才培养有一定的借鉴作用.     

安全渡河问题的计算机求解和模拟

本文介绍利用数学软件包来求解和利用计算机多媒体制作工具来模拟数学模型课程中安全渡河问题的方法     

Simulation study on the formation and transition properties of cluster structures in liquid metals during rapid cooling processes

For the first time, a molecular dynamics simulation study has been performed for a liquid metal system consisting of 50000 atoms to deeply investigate the transitions of microstructure configurations dudng the rapid cooling processes. Especially, the cluster-type index method has been adopted to analyze the transforming and evolving processes of clusters and cluster configurations from liquid metal atoms. It has been found that the bigger cluster configurations in the system are formed by means of connecting some small clusters (they are combined by several smaller clusters), and not taken on the multi-shells configuration accumulated with an atom as the center and the surrounding atoms arranged according to some fixed pattern. With the decrease in temperature, the probability of repetitive appearance for clusters increases largely, which reveals that clusters are indeed possessing a certain relative stability and continuity (namely hereditary effect). These results will give us an important enlightenment to understand not only the forming mechanisms and microscopic processes of the short-order sections and disorder sparse sections in amorphous structures but also the freezing processes of liquid metals.``