基于Agent的语言演化仿真研究

语言的产生及其演化问题是复杂系统研究领域的一个热点问题.研究表明,传统的建模方法无法很好地刻画复杂系统,而基于多Agent的建模仿真方法是当前研究复杂系统的最有力工具之一,有必要进行深入研究.在简单介绍复杂适应性系统、基于多Agent的建模方法的研究概况,以及多Agent建模工具--Repast仿真平台以及它的结构、主要类库与建模步骤后,以语言的产生及其演化问题为研究对象,进行基于多Agent的建模仿真实验,结果表明基于多Agent的建模仿真方法非常合适复杂适应性系统的研究,具有很大的发展空间.     

基于多Agent的蚂蚁觅食过程仿真研究

复杂系统的仿真研究是复杂系统研究领域的一个热点问题.研究表明,传统的建模仿真方法无法很好地刻画复杂系统,而基于多智能体(Agent)的建模仿真方法是当前研究复杂系统的最有力工具之一,有必要进行深入研究.在简单介绍复杂系统以及基于多Agent的建模仿真方法的研究概况后,以蚂蚁觅食过程为研究对象,进行基于多Agent的建模仿真实验,结果表明基本多Agent的建模仿真方法非常适合复杂系统的研究,具有很大的发展空间.     

基于Agent的复杂系统分布仿真建模方法的研究

基于Agent的分布仿真是研究大型复杂系统的一种有效的、重要的方法。为了减小复杂系统仿真的复杂度,增加仿真模型的重用和可维护性,需要研究基于Agent分布仿真的建模方法。首先对复杂系统及其特性进行了分析,对基于Agent的仿真进行了全面的论述,然后对基于Agent的复杂系统仿真中的复杂系统建模分析、Agent建模分析以及Agent的分布进行了分析,给出了基于Agent的复杂系统分布仿真的建模步骤,最后给出了在此建模思想指导下的金融证券市场的建模过程。     

基于多Agent和工作流的业务过程仿真环境

仿真是进行业务过程评价和重组的有效工具.针对目前的业务过程仿真方法的不足:不能有效地对复杂因素进行建模,不能反应复杂的任务分配策略对业务过程的影响,以及缺少分布和可扩展的仿真系统框架,提出了一个基于工作流和多Agent的业务过程仿真环境.在该环境中,人员被建模成Agent,通过Agent的属性和行为能对复杂的因素进行建模,通过Agent之间的招投标机制可以实现复杂的任务分配策略.同时,由于系统采用了基于工作流和多Agent的结构,因此具有很好的可扩展性.最后,给出了系统的实现实例.     

可配置网络式软件系统的可用性预计研究

在复杂系统的建模与仿真研究的基础上,提出了一种基于多Agent的可配置网络式软件系统的可用性预计方法。首先介绍了多Agent系统建模与仿真方法;其次分析了可配置网络式软件系统的特点;然后在研究基于多Agent的网络式软件系统建模与仿真的基础上,研究可配置的行为模型,并建立了基于多Agent的可配置网络式软件 系统可用性仿真方法;最后利用Nctlog。仿真平台,结合实例对可配置的作用进行了可用性预计,并验证了本方法的有效性。     

基于Repast Simphony平台的建模与仿真技术

随着计算机技术的发展, 基于Agent的建模与仿真技术被认为是研究复杂系统的有效方法, Repast Simphony平台为基于Agent的建模与仿真提供了有利条件. 针对如何利用Repast Simphony平台构建复杂系统仿真模型的问题, 重点介绍了Repast Simphony仿真平台, 分析了它的技术优势, 与同类仿真平台进行了比较分析, 并在分析平台主要类库的基础上, 总结出建模仿真的一般流程. 最后, 通过一个改进的Schelling模型仿真实例进一步阐述了利用平台构建复杂系统的设计与实现方法, 对使用Repast Simphony平台进行基于Agent的建模与仿真研究具有一定的指导意义.     

Repast:基于Agent建模仿真的可扩展平台

建模仿真平台为基于Agent建模理论和方法的研究创造了条件.在研究当前流行的基于Agent建模仿真平台不足的基础之上,介绍了一种新的基于Agent建模仿真平台Repast,详细阐述了该平台的设计目标、框架结构及运行机制等内容,并结合一个实例简要说明了Repast模型的设计与实现过程.该平台移植性和可扩展性强,使用方便,易于学习,方便了应用基于Agent建模仿真方法对复杂适应系统及复杂性的研究及探索,同时也为复杂适应系统的研究提供新的思路.     

基于Petri网和Agent的复杂适应系统建模

针对复杂适应系统内部关系繁杂、难于描述及计算机仿真建模困难等问题,提出一种基于时间Petri网和多Agent相结合的建模方法.以Agent为基本建模元素,用Petri网描述Agent内部的行为规则,实现复杂适应系统的Petri网与多Agent相结合的有机建模,可避免Petri网建模引起的模型空间爆炸和Agent内部推理...     

基于CAS理论的多Agent建模仿真方法研究进展

基于复杂适应系统CAS理论的多Agent建模仿真是近年来复杂系统领域的一个研究热点.本文在简单介绍CAS理论的基础上对基于CAS理论的多Agent建模仿真方法的主要研究内容和研究现状进行分类和描述,最后对该研究领域存在的主要问题和发展趋势进行了分析和总结.     

面向Agent的Petri网及其应用

为了更好地刻画单个Asent的行为和多Asent间复杂、并行的动态交互,将面向Agent的设计思想与Petri网建模方法相结合,形成了一种面向Agent的Petri网(AOPN)模型.首先给出了面向Agent的Petri网的形式化定义,然后利用Petri网的建模工具,以网上购物背景下买卖双方简单交互为例,对基于面向Agent的Petri网模型的系统建模方法进行了研究和分析,有效地解决了系统结构复杂性的问题.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).