复杂数字电路多级在线进化技术研究

复杂数字电路的在线进化是目前演化硬件领域的难题之一.本文阐述了基于多级分解进化的复杂数字电路在线进化思想,给出了数字电路进化设计算法,分析了数字电路编码方案,研究了数字电路在线验证评估方法,设计了适应度函数,给出了数字电路在线进化设计实验系统方案.以典型数字电路为例,验证了多级分解进化方法的有效性,实验结果表明,采用多级分解进化方法可大大提高数字电路在线进化设计的速度与成功率,也有利于提高数字电路在线验证评估效率.     

以FPGA和QUARTUS为基础平台的EHW环境实现

在讨论了EHW运行机制的基础上,论述了基于FPGA芯片和QUARTUS Ⅱ开发工具的EHW平台,详细介绍了Tcl脚本语言以及利用批处理技术实现VHDL程序自动处理和配置数据流文件自动下载的具体技术方法。进而,设计并实现了能以闭环方式进行系统演化的实验环境,并在此基础上有效地进行了多种演化策略和进化方式的研究。     

遗传算法及其进化硬件设计研究

遗传算法(Genetic Algorithms，GAs)是进化计算中的重要领域．也是人工智能迅速发展的重要领域，它是一类模拟自然进化过程和达尔文“适者生存”的算法。这一算法企图通过使用诸如交叉、变异等算子从先前的候选解中生成最佳解。进化硬件(Evolvable Hardware，EHW)则是受自然进化得到灵感、设计硬件系统的新型设计方法，它是进化计算技术和电子硬件结合的产物。本文给出GAs在计算机模型中的基本概念．讨论进化再配置硬件的设计，最后给出几个进化实验的例子。     

基于FPGA的数字电路进化设计与实现

针对目前演化硬件研究中的关键问题:电路的数学表示方法、遗传算法和快速重构硬件平台,文章建立了一个用于描述数字电路的电路网络演化模型;设计了矩阵组编码算子,改进了精英保留策略;最后基于虚拟可重构技术在FPGA中建立了一个适于演化操作的硬件平台,实现了数字电路的内部进化;实验结果验证了该模型的可行性与有效性,采用的矩阵组编码算子在(8,8,8,4)演化区域内显著提高了电路演化的速度,为演化硬件的进一步发展了提供新的方法。     

FPGA在演化硬件中的应用

介绍了FPGA的新应用—演化硬件EHW的进展和现状,其中主要包括EHW的概念、工作原理、存在问题和应用领域。阐述了EHW在电路与系统学科中的科学意义及其对新兴电子信息产业将产生的深远影响。     

基于演化母板的通用演化硬件平台研究

作为一种新型的理论研究和实践技术,演化硬件(EHW)在机器学习、人工神经网络、自适应控制、信号处理与识别、容错系统和机器人等方面已经受到了广泛的重视。本文针对FPGA等商用可编程逻辑器件在演化硬件研究中出现的种种问题,提出一个基于演化母板的新型演化平台,并介绍了它的系统结构及工作原理。     

基于演化硬件技术的自适应传感器

未来深空探测、海洋监测等需要系统在恶劣环境条件下长期自主工作的领域对传感器的可靠性提出了更高的要求.由此提出的概念之一就是传感器应该具备自适应能力,能够在恶劣环境条件下进行自我调节,适应新的环境变化而保持功能可用.借鉴达尔文进化论思想的演化硬件(EHW)技术为解决这一问题提供了一种可行方案.探讨了基于可重构器件的EHW技术原理,给出了EHW机制应用于自适应传感器系统的一些方法和演化自适应传感器的结构形式.     

基于精英池演化算法的数字电路在片演化方法

20世纪末演化硬件技术的提出为实现硬件系统的自适应与智能化等特征提供了一种可行的新技术,现阶段电路进化是演化硬件研究的热点之一.该文引入人工经验与规则,提出一种扩展矩阵编码法,保护具有较优结构的电路个体不易被淘汰;其次,基于多目标和局部寻优技术,结合子电路杂交与单元重要性的自适应变异策略,提出了一种设计数字电路的精英池演化算法,并在可编程逻辑器件上实现电路的自主动态重构与评价等演化过程.     

演化硬件在图像边缘检测中的应用

设计基于演化硬件（Evolvable Hardware，EHW）的快速边缘检测进化系统，提出一种适于此系统的图像边缘提取操作结构，给出进化算法的编码方案，设计用于染色体评估的适应度函数，利用标准遗传算法来实现可变结构参数的图像边缘提取进化方法，并采用Roberts，Sobel，LOG，Robinson等传统边缘检测算法与进化方法进行对比试验。结果表明：进化方法边缘检测误差率最低，只有9．87％，其边缘提取的效果优于传统检测方法，     

基于函数级FPGA原型的硬件内部进化

电路进化设计是现阶段可进化硬件（EHW）研究的重点内容，针对制约进化设计能力的主要“瓶颈”，该文提出并讨论了一种简洁高效的内部进化方法，包括基于函数变换的染色体高效编码方案，与之配套的函数级FPGA原型和进化实验平台以及在线评估与遗传数自适应方法等，交通灯控制器，4位可级联比较器等相对复杂且具应用价值的电路的成功进化，证明该方法适用于组合，时序电路的进化设计，并可显著地减少运算量，提高进化设计的速度和规模。     

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).