C＋＋语言中静态数据成员和静态成员函数的研究

本文深入分析了C＋＋语言中类静态数据成员和静态成员函数的作用以及声明和访问方法，指出了程序设计中利用全局变量来实现数据共享的弊端，同时给出了解决方案，也指出了静态成员函数访问非静态成员的解决方法，并举了相应的实例来说明如何正确使用静态数据成员和静态成员函数。     

C~（＋＋）中的操作符重载（续一）

Ｃ~（＋＋）中的操作符重载（续一）ＯｐｅｒａｔｏｒｏｖｅｒｌｏａｄｉｎｇｉｎＣ~（＋＋）ＪＯＯＰ￥／／（上接９４年第４期）现在我们有一个说明复数的类，我们可以说明一个复数类型的对象，并且通过调用成员函数执行对象的操作，认识到无论何时，成员函数被引用都是...     

从C结构串到C＋＋类串

本文以C为元语言,C＋＋为对象语言,以C＋＋类串中的构造函数、析构函数、赋值函数和成员转换函数等概念为例,用C程序描述它们的产生过程,进而用C程序描述C＋＋程序。     

完善C＋＋的虚机制以增强其多态性

在如Ｃ＋＋等强类型面向对象语言中，因仅能通过继承结合虚函数来表达某些动态多态性，从而难以自然有效地描述给某一族类中的各个类都添加一些共同特性。文中提出了的真正虚基类和虚数据成员概念及相应的语言机制可用来方便地解决上述问题，同时又可消除Ｃ＋＋中虚函数与虚基类概念上的不一致，改进和完善强类型面向对象语言中的虚机制，增强其多态性方面的表达能力，并且在多数情况下可以安全、有效地代替受限类属机制和多继承，从     

C＋＋中构造函数的三种调用问题解析

构造函数是一种用于创建对象的特殊成员函数,构造函数的调用顺序问题对类的定义至关重要,本文从简单类对象的创建、类组合（一个类的对象是另一个类的数据成员）和类继承三种情况下分析了构造函数的调用问题,一定程度上诠释了类定义中的这一关键因素,为更好掌握C＋＋的编程思想提供了理论依据和程序示例。     

C＋＋动态数组的实现与重用

数组是应用程序中经常要用到的一种数据结构。为解决C＋＋定义后的数组不能改变其大小的情况,根据软件重用的思想,给出了用函数模板、动态数组类和数组类模板生成C＋＋动态数组的方法,并对这些方法在代码重用方面进行了比较。文中主要给出了动态生成二维数组的函数模板、动态数组类和数组类模板的定义,以及部分成员函数和运算符重载函数的实现代码或算法。以动态生成二维整型数组,进行矩阵的加法运算为例,给出了使用方法。应用文中所给的方法,能满足应用程序中动态定义一维和二维数组的需要。     

用汇编语言解析C＋＋中类和对象各成员内存结构特点

汇编语言是面向计算机硬件的符号化的机器语言,通过学习汇编语言可以加深对计算机内部原理以及高级编程语言的理解。借助汇编语言低级化的特点,通过一个简单的C＋＋小程序和其对应的反汇编代码,从汇编语言的角度详细地分析和展示C＋＋中类和对象各成员在内存中的分布特点,从而帮助读者从本质上理解类、对象、成员变量和成员函数之间的各种关系。     

C^＋＋中模板的妙用

模板是Ｃ＾＋＋中功能最强的特性之一，它允许编程人员只定义一个函数或类的“形状”。本文通过例子介绍了模板的使用，并给出了函数模板，类模板。     

面向对象程序设计(C++)中类的定义

本文讲述了在VisualC 6.0环境下,类的定义的三种方法,并且讲述了在类的外部实现类的成员函数时要注意的问题:包括派生类的构造函数中的初始化表,带缺省参数的成员函数、虚拟成员函数等。     

C^＋＋中＋＋运算符重载的研究与设计

本文对Ｃ＾＋＋中的＋＋（－－）运算符的重载进行了深入研究，对于有序可数的离散事件，提出了一套应用＋＋（－－）运算符求后继的方法，以素数和Ａｃｋｅｒｍａｎｎ函数为例，探讨了＋＋（－－）运算符的前缀形式和后缀形式的重载技巧，并给出了类定义实例。     

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).