一种面向对象的PLC程序设计方法

为了减小经验因素的影响,对设计阶段进行更好的质量控制,借助于面向对象的分析与设计理论,对传统的基于状态转移的PLC程序设计方法进行了改进,提出了一种面向对象的PLC程序设计方法。使用UML建模工具,分别用类图和状态机视图描述控制系统的静态结构和动态行为,进而把状态机视图转化为梯形图。通过把面向对象技术及UML引入传统的PLC控制领域,既提高了PLC程序设计的可靠性,也扩展了面向对象技术和UML的应用领域。     

使用设计模式指导UML类模型的建立

本文分析了基于 UML建立类模型的困难和不足之处 ,通过对设计模式这一被证明行之有效的面向对象技术的探讨 ,提出可以显式地使用设计模式指导 UML 模型的建立 ,并举例说明了这种方法的可行性和有效性 .这样便将对设计模式的讨论纳入到了 U ML的标准之内     

面向对象的数据仓库模型设计

面向对象的方法是软件工程中最主要和最流行的设计方法,UML是面向对象系统的标准建模语言。论文首先分析了数据仓库的多维模型的特点和基本概念,然后给出了用面向对象的技术,并结合UML进行数据仓库模型设计的方法。     

基于UML的CMS系统设计与实现

为了建立标准、通用、适用面广的CMS系统,将面向对象建模语言UML引入CMS系统的设计,采用UML语言建立功能需求模型、静态模型、动态模型,抽象出CMS系统的共同功能特征,可以提高CMS系统的开发效率和软件重用,促进CMS系统的研究和应用.最后采用Rational Rose工具实现CMS系统设计模型,同时结合.NET技术特色实现MVC设计模式,采用效率高的面向对象的方法来创建动态应用程序,提升系统结构优化和系统安全性.     

基于UML的人力资源管理系统的建模

采用面向对象方法,基于UML建模技术对人力资源管理系统进行分析与设计.通过用例图、类图及序列图等UML表示法工具分析设计了人力资源管理系统的静态模型和动态模型,完成了系统开发的分析、设计阶段的工作,并探讨了基于UML的系统建模方法及运用面向对象方法进行系统开发的优势.     

UML与MVC设计模式在社区信息系统中的应用与实现

介绍了UML(Unified Modeling Language)和MVC(Model-View-Controller)设计模式,采用UML和MVC设计模式相结合的方法设计并实现了完全面向对象的、结构健壮的、可扩展的、易于维护的社区信息系统.     

UML和设计模式在PACS中的综合应用

统一建模语言UML(Unifoied Modeling Language)是新近提出的一种重要的面向对象软件开发方法.设计模式是面向对象建模的一种辅助设计手段,它总结了面向对象设计的宝贵经验,使得在遇到相似场景时可以直接套用,提高复杂系统的设计效率.结合所实施的医学影像系统的开发工作,提出了使用UML技术进行整体系统规划设计、使用设计模式细化具体组件和部件的对象建模方法,取得了较好的效果.     

基于UML的教务系统学生端的分析与设计

随着面向对象技术的发展,面向对象的可视化建模语言UML也得到越来越多的应用,在对面向对象及UML建模的相关概念做了简要介绍的基础上,较详细分析了UML建模的几种视图的特点和功用,针对学校教务管理系统的学生端的开发,在分析前期需求的基础上,利用UML进行了系统建模的分析和设计,使用Rational rose软件从不同侧面设计出用例图,顺序图和活动图,从而为系统的开发和实现提供了实施依据.     

基于UML的通用在线考试系统的分析与设计

本文讨论了面向对象技术的基本概念和UML建模语言,分析了通用在线考试系统的总体功能结构,结合软件工程和面向对象技术,设计了基于UML用例图、类图和活动图的通用在线考试系统模型,并运用UML的时序图描述了教师组织考试的工作流程。通过通用在线考试系统开发实例,介绍了如何应用UML的方法设计和开发软件模型。     

基于UP的城市地质信息系统软件开发研究

在城市地质调查的单独领域,虽然各专业软件在设计和开发阶段也使用了面向对象方法和可视化建模工具UML,但只是用对象和UML视图对各地质资料进行了表面化的展示,却没有利用UML的UP方法认识到系统集成和综合应用时的本质问题。文章就UP识别关键任务、业务模型到数据库模型、UP产品实例化等几个问题阐述了几点新想法和解决方案。     

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).