面向粗粒度数据流网络处理器的混合定制硬件加速

本文针对控制流网络处理器固定拓扑结构的限制及指令集并行性开发的不足,将粗粒度数据流设计思想引入到网络处理器体系结构设计中,提出了一种新型粗粒度数据流网络处理器体系结构-DynaNP。DynaNP利用处理引擎(PE)内控制流执行方式获得较高的可编程性,还利用PE间数据流执行方式开发了报文处理中的任务级并行性。为了进一步提高DynaNP的系统流量,面向DynaNP的多核及数据流特性,设计了混合定制硬件加速机制,并详细介绍了实现混合定制硬件加速的关键技术,通过提供统一的混合定制硬件加速接口,可以支持定制指令和协处理器两种典型硬件加速器。     

EDGE结构上一种通过超块重组加速单线程应用的方法

Explicit Data Graph Execution(EDGE)ISA是一种专门为类数据流驱动的分片式众核处理器而设计的指令集体系结构.相较于传统的采用控制流驱动的处理器,EDGE结构以超块(Hyperblock)而不是单个指令作为其执行单位,在超块内部实现数据流执行,超块之间按照推测序保持控制流执行,有利于挖掘指令级并行性.但是,EDGE编译器按照程序的串行执行顺序组织超块,超块间和超块内部受限于数据依赖,削弱了整个程序运行时的潜在数据级并行性和线程级并行性,不利于发挥EDGE分片式结构的优势.本文通过分析EDGE编译器超块组织的特点,结合EDGE结构特有的执行模型,提出一种普适性的超块组织框架来模拟EDGE结构上多线程运行的效果,进一步挖掘EDGE结构运行串行单线程程序时的指令级并行性.本文选用TRIPS微处理器作为EDGE结构的实例处理器,利用矩阵乘法等三个实验验证了我们所提出的框架的可行性,实验结果表明这些应用在TRIPS上获得了较好的性能提升.     

基于SOPC的网络处理器原型设计

网络处理器是一种支持网络协议高速实现的特殊CPU。首先详细分析了网络处理器的结构、功能以及设计的关键技术，然后提出了采用SOPC(System On Programmable Chip)技术实现网络处理器芯片原型的方案，使用该原型可对网络处理器设计中的各种关键技术进行验证。     

一种粗细粒度结合的动态污点分析方法

针对当前污点分析工具不能兼顾速度和精确度的缺陷,研究并实现一种粗细粒度结合的二进制代码动态污点分析方法。对比粗粒度污点分析和细粒度污点分析的实现过程,提出两者结合的新型分析框架。预先在线执行粗粒度污点分析以筛选有效指令,之后离线执行细粒度污点分析以计算污点信息。根据粒度的差异分别建立粗细粒度污点数据的引入标记方法,制定粗细粒度条件下的数据流和控制流传播策略,设计离线轨迹记录结构作为粗细粒度污点分析的传递文件。在原型系统上的测试结果表明,该方法通过在线粗粒度模式保证了污点分析信息采集的快速性,同时采用离线细粒度模式以合理的时间消耗提升了污点分析的精确度。     

ACE编程框架快速通道分析与优化

ACE编程框架为IXP1200网络处理器提供了良好的可编程性，但实际应用中发现其转发性能欠佳．快速通导决定了ACE系统的转发性能，在分析快速通道的基础上，提出出了一种优化快速通道性能的方法，该方法在保持可编程性的前提下，以充分开发报文级并行性为目标，实现了对快速通道资源的合理组织．实际测试表明，优化后的ACE编程框架在转发百兆链路最小报文时吞吐率提高了28．8％．     

基于PicoBlaze的多软核网络处理结构研究

介绍一种基于多个8位CPU软核PicoBlaze的网络处理结构.该结构利用现场可编程门阵列(FPGA)的并行性和网络协议分层结构的特点,可以实现一些相对复杂的网络处理功能,并且易于扩展和开发.通过在FPGA上完整实现一个远程启动服务器端的设计实例,阐明具体的设计方法.     

基于自描述缓冲区的网络处理开发环境

随着通用多核技术的发展,多核处理器在网络核心设备能够提供较高的I/O吞吐能力,并支持更复杂的网络处理,为网络处理与转发带来了前所未有的灵活性和普适性.但是,在核心网络中,多核处理器的处理与转发性能仍然面临着巨大的挑战.首先,随着网络带宽的不断提升,多核处理器需要提供越来越高的处理能力.其次,随着网络业务复杂度的提高,在网络报文处理与转发中,应用对报文的处理开销越来越大,对设备的I/O裸转发能力提出了更高的要求.提出了一种硬件缓冲区管理机制Self-Described Buffer（SDB),具有硬件低开销、软件高性能等优点.基于SDB的机制,设计并实现了一个通用的网络处理开发环境NPDK.NPDK采用零中断、零拷贝方式,提供内核与用户驱动,适用于通用多核CPU系统.不但具有简单、灵活、易开发等特点,而且在内核态下支持用户对每个CPU核上进行异构报文处理编程和在用户态下支持独占式多线程编程与共享式多进程并行编程.测试结果表明,基于SDB的网络处理开发环境在10G速率报文I/O转发性能接近线速,特别是64字节小报文可达到7.49Gbps.目前,NPDK已经在click路由器、OpenFlow交换机和网络探针等方面得到应用.     

数据流驱动的多线程模式在嵌入式多核系统中的应用

数据流驱动相比控制流驱动计算模式,更容易发掘应用程序的并行性,多线程是其必然结果.在嵌入式多核系统中,采用分布和并行的多个处理核来提供高计算能力.数据流驱动的多线程计算模式抽象其中的并行计算、通信、存储和资源限制等模式.适合用来描述多核系统的行为,对性能进行分析和预测.并指导系统设计和开发.     

网络处理器数据处理内核的设计与实现

通用处理器和专用芯片ASIC的数据处理能力无法满足日益增长的网络带宽和各种复杂网络协议的要求,针对该问题,研究网络处理器的系统结构,讨论网络处理器中数据处理内核的设计实现,提出一种可编程的精简指令集计算机(RISC)处理器微结构,对其进行现场可编程门阵列(FPGA)原型验证,结果证明了该设计方案的有效性。     

基于控制流与数据流分离机制的网络服务方法

随着网络应用越来越广泛的出现,不断提高网络服务器性能是学术界长期努力的目标。避免数据重复拷贝是提高服务器性能的有效手段。通过对网络服务器数据流和控制流的分析,发现数据流与控制流捆绑是造成数据重复拷贝的重要原因,并且发现传统的操作系统系统调用设计是造成控制流与数据流捆绑的主要原因。本文提出了采用控制流与数据流相分离的机制,设计新的操作系统服务来解决数据重复拷贝问题,提高网络服务器性能。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

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。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

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QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

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。