埋弧自动角焊机控制系统的研制

采用单片机对埋弧自动角焊机进行控制，实现焊接过程的实时控制，保证焊接电流的跟踪控制及电弧电压的自动调节：实现了焊接小车和送丝电机及焊接参数的闭环控制，经过实验验证，焊接过程稳定，焊缝质量较好，具有一定的实用价值。     

基于支持向量机的纺纱质量预测模型研究

纱线的生产是一个多环节的复杂工业过程．其质量控制大多需要依赖领域专家的个人经验,为此提出一种基于支持向量机的纱线质量预测模型．探讨了模型选择与验证问题,并利用“网格搜索”法对模型参数进行了优化,试验结果表明,在小样本和“噪音”数据环境下．支持向量机模型仍能保持一定的预测精度,与人工神经网络模型相比,更适应于真实纺纱生产过程．     

基于EDA光电检测控制系统设计研究

光电检测控制系统是自动化控制的核心技术之一，其稳定性及其精度决定了自动化控制过程的优劣。设计基于红外传感技术，完成了对棉纺织机械设备等生产产品的实时现场质量检测控制，利用计算机辅助设计EDA软件进行系统仿真测试、电路板网设计。通过零件选型，在实验室调试成功，验证了该设计理论的可行性。     

CD-R生产过程中的质量控制

1、前言在CD-R光盘生产过程中,由于生产工艺的调整、生产环境的变化、原材料的更换以及设备的运行波动都会使产品的质量发生一定的波动,如果波动范围超出一定的控制标准,就需要对产品进行质量等级分类,挑出次品,以维护产品的品质,为了保证出厂产品的质量始终如一,使消费者用得放心,这就需要科学的质量控制手段,科学的质量控制手段不但要使合格品中不存在有次品,也不能把合格品当作次品处理。本文主要阐述生产过程中如何进行抽样检测来准确判断产品的品质。     

基于改进Apriori算法的烟草生产控制系统设计

为确保烟草生产质量控制效果，减小不同烟草材料质量评估与实际评估结果偏差，该文设计基于改进Apriori算法的烟草生产控制系统。系统主要设计了用户权限管理模块、烟草生产制造数据管理模块、烟草生产制造质量检测模块和质量评价模块。利用三维矩阵改进Apriori算法，对数据实行处理，通过建立三维矩阵直接生成频繁序列，精简数据库，提高数据挖掘效率。将系统模块与技术相结合，完成烟草生产控制系统的整体设计。结果表明，通过对烟草指标实行平均值、质量控制评价得分与实际值对比测试，验证了该系统的评价效果较好，能够有效减小不同烟草材料质量控制评估与实际评估结果偏差。     

汽油管道调合优化控制方法及半实物仿真实验平台的研究

汽油调合是炼油厂生产汽油过程中的重要工序,在该过程中,将各种组分油按照一定的比例进行混合,组分油的调和比例直接影响着成品油的质量。本文采用了优化设定层和回路控制层两层结构所组成的汽油管道调合优化控制方法。并结合西门子S7-300 PLC、Matlab、Visual Basic以及SIMATIC WinCC开发汽油管道调合优化控制系统的半实物仿真平台,达到了对汽油管道调合优化控制系统的验证目的。     

钢球加热炉温度调节系统的开发

在钢球热处理过程中,温度控制的精确性对钢球质量和硬度的影响极为重要。为此,基于对加热工况与工艺参数变化的理解,采用迭代算法和参数滚动优化的方法,对每一个钢球总加热时间进行预测,并建立预测控制的数学模型;再根据经验参数库,完成控制系统中相应系数的修正,实现钢球温度的精确控制。温度的调节控制在生产实践中是可行的,生产出来钢球的温度合格率达到98%以上,验证了钢球温度调节系统的先进性与适应性。该控制系统的控制方式在工业控制领域具有一定的参考价值。     

使用SPC技术提高卷烟包装生产过程质量水平的研究

为提高卷烟包装生产过程质量水平,需进行生产过程质量控制优化设计。提出了基于SPC技术的卷烟包装生产过程质量水平控制模型,进行了卷烟包装生产过程质量水平控制的博弈模型设计。采用质量约束和效益约束结合的方式进行卷烟包装生产过程质量水平的均衡调度模型设计,构建过程控制的统计特征量,采用SPC技术建立卷烟包装生产过程质量水平的控制目标函数,利用约束进化方法优化控制目标函数,使用自适应宏观决策调度方法实现卷烟包装生产过程质量控制优化。仿真结果表明,采用该方法进行卷烟包装生产过程质量水平控制的误差收敛性较为稳定,控制误差较低,提高了卷烟包装生产过程质量水平和效益。     

遗传算法在pH过程控制中的应用

pH(酸碱度)控制广泛存在于化工等生产过程之中,属于典型的过程控制时象.pH控制不佳可能会在化工生产过程中造成生产过程波动,质量不稳定,产量降低,原材料浪费,装置腐蚀和环境污染等状况.因此,优良的pH控制对化工生产非常有必要.pH控制过程具有独特的对象特性,这些特性给控制带来了较大的难度.本文在分析以往pH控制方法的基础上,应用传统控制算法--PID结合遗传算法实施pH控制.该控制方法在文中给出了详尽的介绍,并通过仿真验证了其可行性.     

基于核函数的模糊过程能力评价方法及应用

在现代工业生产中,由于设备运行的生产过程和环境比较复杂,用数学模型方法和基于先验知识的在线评价来分析生产过程的质量、效率以及可靠性存在一定的难度。为此提出针对流程工业的日常操作数据的基于核函数的模糊过程能力评价方法,并提出了模糊过程能力评价判据,及时控制生产过程存在的问题,并进行预警。通过选取生产过程中的关键参数变量,并采用层次分析融合法来确定生产过程总的过程能力指数。提出方法克服了传统过程能力易受数据波动所带来的不确定性的影响,提高了评价的适应性。将提出方法应用于乙烯裂解炉的裂解工艺,验证了提出方法的适应性和有效性。     

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).