基于μC/OS-Ⅱ的μC/IP协议栈在ARM系统中的实现

深入分析了μC/IP协议栈,阐述了其移植原理和实现方案,并给出了在具体软硬件平台上的移植实例.首先,通过分析μC/IP协议栈,结合实时内核μC/OS-Ⅱ与32位ARM7 Core的软硬件平台,论述了μC/IP协议栈的移植原理.然后,根据TCP/IP各层协议的具体实现提出了μC/IP协议栈移植与裁减的一种可行方案.最后,在基于μC/OS-Ⅱ与ARM7 Core的软硬件平台上实现了μC/IP协议栈的移植.实验结果表明移植后的协议栈实现了网络的基本功能,且运行稳定.开源μC/IP协议栈的移植实现,为基于μC/OS-Ⅱ的Internet嵌入式系统应用提供一个小型可裁减的TCP/IP协议中间件.     

功放预失真系统中嵌入式以太网的设计

针对商用嵌入式TCP/IP协议栈费用昂贵的情况并根据功放预失真系统网络通信特点,提出了基于SOPC技术的嵌入式以太网通信模块设计方案。实现了软核NiosⅡ处理器和实时多任务操作系统μC/OS-Ⅱ为中心的硬件平台和软件驱动的设计、多任务操作系统μC/OS-Ⅱ的移植以及嵌入式TCP/IP协议栈的设计,最终在Stratix EP2S60F1020C4开发板上通过了验证。     

一种基于μC/OS-Ⅱ的嵌入式以太网通信实现方法

为实现远程数据采集和实时监控等功能,网络化成为新一代嵌人式系统发展的重要趋势,提出了一种新的低成本以太网接入方案;根据嵌入式系统软、硬结合紧密的特点,选取具有网络模块的PIC18F97J60单片机作为硬件平台,通过移植μC/OS-Ⅱ操作系统,实现嵌入式以太网接入的功能;针对μC/OS-Ⅱ本身不支持TCP/IP网络通信协议,将开源的TCP/IP协议栈LwIP移植到μC/OS-Ⅱ,解决了基于μC/OS-Ⅱ的网络通信问题;通过将硬件电路板与PC机系统调试,测试结果表明,本系统可以很好地实现嵌入式系统与以太网通信的功能.     

Cortex-A8平台的μC/OS-Ⅱ及LwIP协议栈的移植与实现

提出一种嵌入式实时操作系统设备实现接入以太网功能的方案。利用TI公司推出的TMS320DM8168 DaVinciTM数字多媒体处理器的Cortex-A8平台进行μC/OS-Ⅱ和LwIP协议栈的移植并实现嵌入式TCP/IP网络协议。通过对Cortex-A8内核体系结构研究,详细阐述了μC/OS-Ⅱ和LwIP针对Cortex-A8的移植要点与LwIP的高效邮箱机制的实现并给出部分关键代码。通过系统多任务调度及Web server功能应用的测试验证:移植操作系统运行正常,网络通信成功。在嵌入式设备上实现了嵌入式TCP/IP协议,使嵌入式实时操作系统设备具备了接入以太网的功能。     

基于μC/OS-Ⅱ操作平台的嵌入式电网监测仪的研制

μC/OS-Ⅱ是一种适用于嵌入式系统的源码开放的占先式实时多任务操作系统.本文讨论了基于μC/OS-Ⅱ嵌入式系统的网络通信实现,包括μC/OS-Ⅱ实时操作系统、LwIP协议栈的移植和网络设备驱动程序的建立以及系统任务的调度.     

基于ARM的嵌入式通信系统设计与实现

介绍了一种基于ARM的嵌入式通信系统的新方法;从嵌入式处理器的设计、串口电路的设计、存储系统的设计、以太网电路的设计、μC/OS-Ⅱ操作系统的移植、串口通信协议的编写、TCP/IP协议栈的选用等方面详细介绍了整个系统平台的设计实现过程.     

LwIP协议栈在SoPC系统中的实现

提出了基于μC/OS-Ⅱ的LwIP协议栈在SoPC系统中实现的方案.介绍了嵌入式TCP/IP协议栈LwIP,阐述了其移植原理;在SoPC系统上实现了LwIP协议栈的移植,并给出了在具体软、硬件平台上的移植实例.实验结果表明:移植后的协议栈实现了网络的基本功能,且运行稳定,为SoPC类型的Internet嵌入式系统应用提供了一个基于μC/OS-Ⅱ的小型网络模块.该方案可应用于信息电器和网络化的仪器、仪表方面.     

基于ATmega128嵌入式网络接口的设计与实现

设计了以ATmega128为核心的以太网接口实现方案,描述了该系统硬件架构的设计方法.在系统上移植了μC/OS-Ⅱ操作系统,对TCP/IP协议栈提出了裁剪和改进方法,重点阐述了基于μC/OS-Ⅱ消息机制和函数调用的TCP协议的模块结构.最终给出了系统性能测试结果.     

基于μC/OS-II的μC/IP协议栈在ARM系统中的实现

深入分析了μC/IP协议栈,阐述了其移植原理和实现方案,并给出了在具体软硬件平台上的移植实例。首先,通过分析μC/IP协议栈,结合实时内核μC/OS-II与32位ARM7Core的软硬件平台,论述了μC/IP协议栈的移植原理。然后,根据TCP/IP各层协议的具体实现提出了μC/IP协议栈移植与裁减的一种可行方案。最后,在基于μC/OS-II与ARM7Core的软硬件平台上实现了μC/IP协议栈的移植。实验结果表明:移植后的协议栈实现了网络的基本功能,且运行稳定。开源μC/IP协议栈的移植实现,为基于μC/OS-II的Internet嵌入式系统应用提供一个小型可裁减的TCP/IP协议中间件。     

实时操作系统μC/OS-Ⅱ下TCP/IP协议栈的实现

结合在ez80和ARM 7两种系统上的具体实现,说明如何在嵌入式实时操作系统μ C/O S-Ⅱ上移植、实现LwIP这套TCP/IP协议栈,使μC/OS-Ⅱ成为支持网络的RTOS.     

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).