双CAN总线的机载网络控制器设计

基于航空电子综合化的要求,提出一种新的航电互联方案,结合小型飞行器多传感器和小数据量特点设计一种机载共享式网络。采用DSP作为处理器,SJA1000进行双CAN扩展,使用6N137进行信号隔离,并使用PCA82C250作为CAN控制器接口芯片,进行网络控制器的硬件设计;网络通讯协议采用应答式交换数据,在此基础上,对软件流程和代码进行设计;半物理仿真实验结果表明该系统运行良好,能够满足小型飞行器控制网络的实时性与多结点要求;同时系统具有可靠性高与开放性等特点。     

面向网络处理器的软件组件框架研究

网络处理器通常由多个异构的处理和内存单元通过片上网络连接构成,其目标应用需要在Gbit/s到几十Gbit/s的网络环境中以线速处理数据包。基于网络处理器的应用有实时、资源受限和异构的特点。组件技术对于复杂的嵌入式系统是一种十分有前途的方法。本文以一种典型的网络处理器为例,说明了在基于网络处理器的系统中应用组件技术时,对组件框架的要求,讨论了组件组合框架和运行时框架,并定义了组件框架服务。利用提出的组件框架,可以实现软件性能工程。     

移动设备中异构处理器平台的能量优化设计

由于移动设备含有多个传感器,系统往往需要运行连续的感知任务。移动设备中的应用处理器能有效地运行计算密集型任务,而对于连续的感知任务将消耗大量的能量。为了提高移动设备的能量利用率,在包含应用处理器和低功耗处理器的异构处理器上提出了一种异构处理器平台能量优化方法。首先,根据处理器平台的实际能耗和理想能耗提出了能量比例因子。其次,提出了含有两个异构处理器平台的应用程序划分方法。最后,通过模拟器实验验证了该方法的有效性。模拟实验表明,由于将感知任务迁移到低功耗处理器上运行,所提出的优化方法能大大提高移动设备的能量利用效率。     

轻量级虚拟机软件技术——LVMM

为提高PC系统的可管理性和安全性,提出一种轻量级虚拟机软件技术——LVMM。定义活跃用户域,可直接访问除磁盘和网络之外的物理设备,以及虚拟磁盘和虚拟网络设备。保证在保持PC使用模式基本不变的前提下,可在同一平台上同时运行多个用户虚拟系统,且支持独立于用户操作系统的资源访问控制。经测试,LVMM原型系统具有较小的整体虚拟化开销。     

基于NSGA-II的嵌入式系统软硬件划分方法

软硬件划分是软硬件协同设计中的一个关键问题。针对单处理器嵌入式系统,提出将NSGA-II应用于软硬件划分中,该算法一次运行可以获得多个Pareto最优解,为各个目标函数之间权衡分析提供了有效的工具,提高了设计效率。结果表明,通过该划分方法,在满足系统性能要求下,可为复杂嵌入式系统提供多个设计目标的全局优化方案。     

用51内核网络单片机构成的远程监控系统

提出一种基于 51 内核网络单片机的嵌入式远程监控系统方案,介绍以 DS80C400 单片机为核心的系统硬件构成和基于 TINI 运行环境的应用程序设计方法。该方案可以实现串口、CAN 总线等轻量级网络和以太网或 In t ern e t 的互连,并具有体积小,性价比高的特点。     

一种基于网络处理器的入侵检测防御系统的设计与实现

入侵检测防御(IDP)系统是一种新兴的代表未来发展方向的维护网络安全的重要工具。首先提出一种由IDP系统构建的网络安全体系结构,进而重点讨论如何采用网络处理器(NP)实现轻量级IDP系统。研究结果表明,基于IDP构架的网络安全系统更具安全性,由NP实现的轻量级IDP系统可满足中小企业用户对网络安全的需求。     

嵌入式MPEG4视频服务器设计和实现

本文提出并设计嵌入式MPEG4视频服务器视频监控系统,以双核嵌入式处理器BF561为硬件平台,搭建一个网络可访问的流媒体服务器系统。该服务器至少提供5个远程用户的网络登陆和视频图像的实时传输,同时,详细地论述了系统设计方案,硬件和软件方面的设计,并给出实际运行结果。     

基于IXP2400的研究与开发平台体系结构

INTELIXP2400是一种典型的网络处理器,集成了一个Xscale的通用控制处理器和8个特别设计的微引擎(ME),以及其他协处理器和多种存储设备。IXP2400要与其他设备一起构成完整的应用系统。基于IXP2400的软件框架可以给应用程序提供较好的模块性和可移植性,同时由于IXP2400的完全可编程特性,搭建一个基于IXP2400网络处理器和IXP2400软件框架的应用系统开发和研究平台,对研究网络应用的特征和网络处理器的体系结构都很有意义。     

网络处理器的分析与研究

目前,网络在提高链路速率的同时出现了大量的新协议及新服务,而传统的网络设备一般采用专用硬件芯片或者基于纯粹的软件方案,很难兼顾性能与灵活性两方面的要求.为此,一种并行可编程的网络处理器被引入到路由器(交换机)的处理层面.它基于ASIP技术对网络程序处理进行了优化,同时还兼有硬件和软件两种方案的特点.网络处理器的出现将经典的"存储-转发"结构变为"存储-处理-转发",这为复杂的QoS控制和负载处理提供了可能.从网络处理器本身及其应用两个角度出发,介绍了相关的研究工作,分析了系统特点和面临的挑战,并展望其未来的发展方向.     

Codes and Bernoulli partitions

We associate to a maximal codeX on an alphabetA a dynamical system Ω; our main result proves that the property of unique decipherability implies that the partition of Ω associated to the letters ofA is a Bernoulli partition. Surprisingly it is possible to give two very different proofs of this result: the first one uses probability measures on monoids together with methods from automata theory; the other is based on results of entropy theory.     

移动自组网中基于电源消耗的数据位置管理策略

在移动自组网中,网络频繁的断接使得数据的可访问性低于传统的固定网络中的数据可访问性。当网络中存在一个数据项的多个副本时,应避免对某一个数据项的所有访问都集中在某一台移动主机上,从而防止主机电源耗尽而脱离整个网络,降低数据的可访问性。本文基于对移动主机的电源能力的考虑,提出了一种新的数据项或副本位置管理的方法,有效的避免因为电源耗尽而导致的网络分裂,从而保证了数据的可访问性。     

Learning knowledge bases of multi-objective evolutionary fuzzy systems by simultaneously optimizing accuracy, complexity and partition integrity

In the last few years, several papers have exploited multi-objective evolutionary algorithms (MOEAs) to generate Mamdani fuzzy rule-based systems (MFRBSs) with different trade-offs between interpretability and accuracy. In this framework, a common approach is to distinguish between interpretability of the rule base (RB), also known as complexity, and interpretability of fuzzy partitions, also known as integrity of the database (DB). Typically, complexity has been used as one of the objectives of the MOEAs, while partition integrity has been ensured by enforcing constraints on the membership function (MF) parameters. In this paper, we propose to adopt partition integrity as an objective of the evolutionary process. To this aim, we first discuss how partition integrity can be measured by using a purposely defined index based on the similarity between the partitions learned during the evolutionary process and the initial interpretable partitions defined by an expert. Then, we introduce a three-objective evolutionary algorithm which generates a set of MFRBSs with different trade-offs between complexity, accuracy and partition integrity by concurrently learning the RB and the MF parameters of the linguistic variables. Accuracy is assessed in terms of mean squared error between the actual and the predicted values, complexity is calculated as the total number of conditions in the antecedents of the rules and integrity is measured by using the purposely defined index. The proposed approach has been experimented on six real-world regression problems. The results have been compared with those obtained by applying the same MOEA, but with only accuracy and complexity as objectives, both to learn only RBs, and to concurrently learn RBs and MF parameters, with and without constraints on the parameter tuning. We show that our approach achieves the best trade-offs between interpretability and accuracy. Finally, we compare our approach with a similar MOEA recently proposed in the literature.     

一种基于黑板模型的多Agent系统通信方法

本文以人工智能领域中的黑板模型为基础 ,提出了在 Internet环境中多 Agent系统 (MAS)的通信方法 .该方法可用于异构的 MAS系统间的通信 .首先把 MAS系统的通信环境划分为不同的层次 ,然后用黑板模型对这些层次进行了描述 .基于这种描述给出了 MAS系统通信用协议和相关参数 .而且 ,还在这些参数中设置了有关服务质量的元素 .     

Parallel multilevel algorithms for hypergraph partitioning

In this paper, we present parallel multilevel algorithms for the hypergraph partitioning problem. In particular, we describe for parallel coarsening, parallel greedy k-way refinement and parallel multi-phase refinement. Using an asymptotic theoretical performance model, we derive the isoefficiency function for our algorithms and hence show that they are technically scalable when the maximum vertex and hyperedge degrees are small. We conduct experiments on hypergraphs from six different application domains to investigate the empirical scalability of our algorithms both in terms of runtime and partition quality. Our findings confirm that the quality of partition produced by our algorithms is stable as the number of processors is increased while being competitive with those produced by a state-of-the-art serial multilevel partitioning tool. We also validate our theoretical performance model through an isoefficiency study. Finally, we evaluate the impact of introducing parallel multi-phase refinement into our parallel multilevel algorithm in terms of the trade off between improved partition quality and higher runtime cost.     

A clustering method for concurrent photos obtained from multiple cameras using max-flow network model

With the popularization of digital cameras, the use of several cameras by group photographers at the same event is becoming common. Photographers can share their contents and even take pictures of each other. So it is becoming important to manage concurrent photos from multiple cameras in order to classify many accumulated photos into proper clusters. In this paper, we propose a novel photo clustering method based on the max-flow network algorithm, and we visualize a network graph for cluster verification. To apply our algorithm, input concurrent photos are used to create an edge-weighted graph structure. In order to transform the photo clustering problem into a graph partition one, first we need to construct an Augmented Concurrent photo Graph (ACG) and then rewrite our original problem in terms of the graph partition one using the min-cut max-flow network model. The previous methods dealt with photo clustering as a 1-D problem using a linear partition. But we consider clustering for concurrent group photos as a 2-D partition based on other users’ photo contents. Each photo is used to create a node and similarities between photos are used to create the edge weights (capacities) of the network. We partition the network into two subgraphs according to the min-cut, which represents the weakest edge connections between the photos. Using repeated graph partitions for each subgraph (sub-network), we can obtain suitable subgraphs corresponding to photo clusters. The graph construction or partition can be adjusted according to user preferences in order to obtain the intended results.     

Hybridization methods for the analysis of nonlinear systems

In this article, we describe some recent results on the hybridization methods for the analysis of nonlinear systems. The main idea of our hybridization approach is to apply the hybrid systems methodology as a systematic approximation method. More concretely, we partition the state space of a complex system into regions that only intersect on their boundaries, and then approximate its dynamics in each region by a simpler one. Then, the resulting hybrid system, which we call a hybridization, is used to yield approximate analysis results for the original system. We also prove important properties of the hybridization, and propose two effective hybridization construction methods, which allow approximating the original nonlinear system with a good convergence rate.     

集成CPU-GPU架构上的列存储连接优化技术研究

集成多核CPU-GPU架构已经成为计算机处理器芯片的发展方向。利用这种架构的并行计算能力进行数据处理已经成为了数据库领域的研究热点。为了提高列存储系统的查询性能,首先改进了已有协处理机制中的负载分配策略,通过监测数据库系统CPU占用率,动态地为处理器提供合理的数据划分;然后,针对集成多核CPU-GPU架构上的数据预取机制,提出了一种确定预取数据大小的模型,同时,针对GPU访存的特点,进行了GPU访存优化;最后,使用OpenCL作为编程语言,实现了一种集成多核CPU-GPU架构上的列存储排序归并连接算法,并采用提出的方法对连接处理进行优化。实验证明,所提优化策略可以使列存储系统排序归并连接性能提升33%。     

多总线多DSP实时图像处理操作系统的设计与实现

该文针对多总线多 DSP实时图像识别系统 ,设计并实现了一个并行操作系统 .它包括嵌入到 DSP芯片上的操作系统和运行在 PC机上的协议软件两部分 .协议软件提供一个人机界面 ,接收算法的分解信息 ,并将其按一定的数据结构组织 ,再将所有的子任务及其分解信息连接成一个作业 .DSP上的操作系统支持作业从上位机上加载 ,或通过 EPROM加载 .操作系统支持 VXI总线标准 ,并提供了数据通信、任务分配和并发进程管理等功能 .它根据任务分解信息 ,分配硬件资源 ,构造数据流向 ,建立子任务相互间的同步关系 ,完成与上位机的联络并输出结果 .实验结果表明 ,该文设计的硬件及其操作系统能够适应不同并行结构的需要 ,并得到满意的图像并行处理效果 .     

Lightweight dynamic partitioning for last-level cache of multicore processor on real system

With rapid development of multi/many-core processors, contention in shared cache becomes more and more serious that restricts performance improvement of parallel programs. Recent researches have employed page coloring mechanism to realize cache partitioning on real system and to reduce contentions in shared cache. However, page coloring-based cache partitioning has some side effects, one is page coloring restricts memory space that an application can allocate, from which may lead to memory pressure, another is changing cache partition dynamically needs massive page copying which will incur large overhead. To make page coloring-based cache partition more practical, this paper proposes a malloc allocator-based dynamic cache partitioning mechanism with page coloring. Memory allocated by our malloc allocator can be dynamically partitioned among different applications according to partitioning policy. Only coloring the dynamically allocated pages can remit memory pressure and reduce page copying overhead led by re-coloring compared to all-page coloring. To further alleviate the overhead, we introduce minimum distance page copying strategy and lazy flush strategy. We conduct experiments on real system to evaluate these strategies and results show that they work well for reducing cache misses and re-coloring overhead.