基于RLS自适应逆控制理论的船舶自动舵研究

本文探讨了自适应逆控制理论中的对象动态控制问题和对象扰动控制问题，并且针对船舶模型特性，用最小二乘法对船舶进行模型参数辩识和控制器的设计。仿真结果表明。与PID控制相比，自适应逆控制方法具有动态响应快，抗扰动性好等特点。     

基于询问-回答模式的对象控制模型的实现

在诸多系统设计中，系统需要管理大量具有内在关联性相似性的对象系统（通常表现为对象树或对象图的形式）。通常采用的方法是系统集中管理和控制，根据对象的互异性特征，选取指定的对象和决定对象如何访问。这种集中控制的弊端是管理复杂、成本高，容易造成错误，并且可扩充性差。文章介绍了一种基于询问-回答模式的对象控制模型，有效地解决了这个问题。     

基于RBF网络自整定PID控制的应用研究

经典PID的控制参数难以精确整定，且依赖于对象的数学模型，故自适应性较差，很难适应具有非线性、时变不确定性的被控对象，控制精度难以保证。该文对纯滞后工业对象提出了一种基于RBF神经网络PID参数自整定的控制方法，采用将RLS算法和梯度法相融合的新型学习算法，并将这种控制方法与PID控制器相结合应用于纯滞后工业对象中，克服了不确定性对控制对象性能的不利影响，解决了传统PID控制鲁棒性差，及需要预先知道受控对象精确数学模型的问题。仿真结果表明了该方法的鲁棒性和跟踪性能均优于传统PID控制方法。     

基于散射模型的Ｈ∞ 控制系统的稳定性*

本文利用（Ｊ，Ｊ＇）－无损矩阵的性质，研究了基于散射模型的Ｈ∞控制系统的闭环稳定性，获得了广义对象的散射模型为（Ｊ，Ｊ＇）－无损的Ｈ∞控制问题可解的充要条件。与文［１］中关于广义对象为一类内矩阵的Ｈ∞控制问题求解的结果相比，本文的结论对广义对象的限制要弱。     

真空冻干计算机控制系统的设计与应用

介绍了真空冻干的控制系统的总体设计思路，首先讨论了控制对象的特殊性，选择适合的控制算法，在传统的PID控制算法的基础上根据控制对象的特点对控制算法加以改进，以获得良好的动稳态响应，并对Windows操作系统下控制软件需要解决的实时性问题和MFC编程应用程序结构的组织问题进行了论述。     

含有不确定因素的模型检验及其非伪概率估计*

本文研究了在控制对象的模型具有不确定的建模误差时的模型检验问题，并给邮了控制对象的模型不能被实验数据所否定的概率的估计。     

不稳定对象的PID控制

对于不稳定对象的控制，常规的稳定裕度和性能指标已不适用，为此讨论了控制不稳定对象时的下幅值裕度和相位裕度的取值范围,给出了灵敏度函数，并讨论了用H∞设计时性能权函数的选择问题。     

网络控制系统中基于时延辨识的模糊控制器研究

针对网络控制问题，建立包含变网络时延及网络传输丢包等的统一模型．提出基于允许误差阈值及最大时延等多重准则的网络调度算法．在被控对象模型已知的情况下，本文采用模糊控制器作为Smith控制的内模控制部分，同时将Smith预估环节与被控对象放在一处，减少了冗余信息的传输，补偿了网络时延．仿真结果说明该调度算法及控制方案对于模型精确已知的一类网络控制对象能取得较好的控制效果．     

基于模糊模式与免疫功能的模糊控制系统设计方法

模糊控制系统的设计面临着两个难题，一是模糊控制规则的适应性问题；二是稳定性分析问题．为解决这两个问题．受经典控制利用控制对象的数学模型分析系统稳定性的启示，构造模糊对象的模糊模式来分析模糊系统的稳定性，并提出免疫功能，用以解决通常搜索算法在模糊模式系统辨识中完备性与健全性的不充分问题．     

基于半实物仿真的教学系统——在自动化学科控制实验上的应用

为解决自动化学科控制实验教学中存在的实验设备不足、场地有限、信息化教学手段缺乏的问题，设计开发了用于控制实验的半实物仿真系统。系统根据实际实验中被控对象特性进行3D建模和数学建模，实现虚拟被控对象和控制器之间的实时通信，完成控制器对虚拟被控对象的实时控制功能。针对自动化学科控制实验内容和特点设计的半实物仿真教学系统符合教学需求，能有效提高教学质量。     

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).