一个基于持续消息的分布式工作流管理模型

提出了一种新的分布式结构,在这个结构中,排除了工作流系统对一个集中式数据库的依赖,而是用持续消息的方法将与过程执行有关的信息存储起来,使过程的执行是完全分布式的,并且每个节点都是各自独立的。采用这种方式能增强对错误的恢复能力以及构造系统的灵活性和扩展性。     

一种分布式 ETL 工具的设计与实现

传统的ETL工具有集中执行、对服务器性能要求高等缺点,针对这些缺点,本文提出了一种基于Hadoop的分布式ETL系统。该系统在分布式文件系统基础上,利用相应的数据过滤器和Hadoop强大的并行处理能力,实现了集群分布式执行ETL流程。该分布式ETL系统具有较高的可扩展性和吞吐效率,同时能够自动实现负载均衡,执行效率高。     

基于XML—RPC的分布式地理信息系统计算模型

分布式异构 GIS系统集成与互操作是 GIS应用发展的趋势和方向 .在 WMS(Web Map Service)和 GML研究的基础上 ,采用 XML 技术和客户机 /服务器通用分布式计算模型 ,提出了一种基于 XML RPC的分布式 GIS计算模型 ;基于 XML- RPC模型 ,设计了分布式 GIS系统中基本 GIS操作和 GIS数据资源的 XML 抽象与表达 ;抽象出了 L og In、L og Out、Get Capability、Get Map、Get Ftr Info、Get Sel Ftrs、Get Them e Map、Get Stat Map 等 8个Geo Processing元操作 ;定义了各个元操作的 XML- RPC请求与响应的 XML 数据格式协议 ,并实现了一个简化的原型系统从而验证了该模型的技术可行性、实用性 ,为第 2代 Web GIS的产品化奠定了理论模型和技术基础     

A computation offloading scheme on handheld devices

In this paper, we present a computation offloading scheme on handheld devices. This scheme partitions an ordinary program into a client–server distributed program, such that the client code runs on the handheld device and the server code runs on the server. Our partition analysis and program transformation guarantee correct distributed execution under all possible execution contexts. We give a polynomial time algorithm to find the optimal program partition for given program input data. We use an option-clustering approach to handle different program partitions for different program execution options. Experimental results show significant improvement of performance and energy consumption on an HP IPAQ handheld device through computation offloading.     

基于扩散卡尔曼滤波算法的目标跟踪估计

针对节点网络上的目标跟踪,提出一种基于扩散Kalman滤波算法的分布式跟踪估计。假设该节点网络系统按照线性状态空间模型演进,网络中的每个节点获取与未观察到的状态线性相关的测量值;对于每个测量值和每个节点,采用来自邻近区域的数据计算出一个局部状态估计值;采用一个基于扩散矩阵和连接矩阵的扩散步骤,将前面计算得到的邻域估计值在整个网络上扩散,从而使得每个节点获得关于系统状态的最佳跟踪估计。仿真实验结果表明,该算法不仅在平均均方偏差性能方面可与集中式Kalman滤波跟踪算法相比拟,而且在平均能耗方面优于对比算法。     

Mobile-agent-based collaborative sensor fusion

Information fusion can assist in the development of sensor network applications by merging capabilities, raw data and decisions from multiple sensors through distributed and collaborative integration algorithms. In this paper, we introduce a multi-layered, middleware-driven, multi-agent, interoperable architecture for distributed sensor networks that bridges the gap between the programmable application layer consisting of software agents and the physical layer consisting of sensor nodes. We adopt an energy-efficient, fault-tolerant approach for collaborative information processing among multiple sensor nodes using a mobile-agent-based computing model. In this model the sink/base-station deploys mobile agents that migrate from node to node following a certain itinerary, either pre-determined or determined on-the-fly, and fuse the information/data locally at each node. This way, the intelligence is distributed throughout the network edge and communication cost is reduced to make the sensor network energy-efficient. We evaluate the performance of our mobile-agent-based approach as well as that of the traditional client/server-based computing model, vis-à-vis energy consumption and execution time, through both analytical study and simulation. We draw important conclusions based on our findings. Finally, we consider a collaborative target classification application, supported by our architectural framework, to illustrate the efficacy of the mobile-agent-based computing model.     

基于IR-UWB雷达的多视角融合动态目标追踪

近年来,对运动目标的定位和追踪被广泛地应用于室内导航、智能家居、安防监控和智慧医疗等场景.基于无线射频信号的非接触式定位追踪受到了研究人员的广泛关注,其中基于商用IR-UWB的技术能够以较低的成本和功耗实现目标定位和追踪的功能,具有较强的发展潜力.然而,现有工作大多存在以下问题:1)追踪场景受限,只针对理想情况下室外或者相对空旷的室内场景进行建模和处理; 2)目标的运动状态受限且建模过于理想; 3)虚假动态目标引起的追踪精度不足.为了解决这些问题,在理解多径场景下接收信号谱组成的基础上,提出一个基于IR-UWB的动态目标追踪方法.首先提取原始信号谱中动态成分,并利用基于高斯模糊的多径消除和距离提取算法,消除了多径干扰,仅保留与运动目标直接相关的一次反射信息,从而准确地获取了目标的距离变化曲线.随后,提出多视角融合算法,将不同视角上的设备距离信息进行融合,实现对自由活动目标的准确定位和追踪.此外,还搭建一个基于低成本商用IR-UWB雷达的实时动态目标追踪系统.真实室内家居场景中的实验结果表明,系统估计的人体中心的位置与真实运动轨迹的误差始终小于20 cm.在改变实验环境、实验者、活动速度...     

基于C/S的计算在颗粒运动仿真中的应用研究

该文介绍了一个基于服务器和客户机分布式计算的颗粒运动仿真系统。在仿真实验中，单机系统无法满足仿真的各项指标要求，特别是用户交互的响应速度。针对各个仿真模块的特点，按功能特性将其分布到客户机和服务器上。基于空间数据分割和对相邻区粒子的预测，大大地减少了任务重新分配时客户机和服务器之间的通信。在局域网上，实现了客户机和服务器的互联和管理。实验表明。仿真实验的计算效率等得到了提高，提高了系统的人机交互响应速度。     

Self-adaptive morphable model based collaborative multi-view 3d face reconstruction in visual sensor network

3D face reconstruction is an efficient method for pedestrian recognition in non-cooperative environment because of its outstanding performance in robust face recognition for uncontrolled pose and illumination changes. Visual sensor network is widely used in target surveillance as powerful unattended distributed measurement systems. This paper proposes a collaborative multi-view non-cooperative 3D face reconstruction method in visual sensor network. A peer-to-peer paradigm-based visual sensor network is employed for distributed pedestrian tracking and optimal face image acquisition. Gaussian probability distribution-based multi-view data fusion is used for target localization, and kalman filter is applied for target tracking. A lightweight face image quality evaluation method is presented to search optimal face images. A self-adaptive morphable model is designed for multiview 3D face reconstruction. To adjust the self-adaptive morphable model, the optimal face images and their poses estimation are used. Cooperative chaotic particle swarm optimization is employed for parameters optimization of the self-adaptive morphable model. Experimental results on real data show that the proposed method can acquire optimal face images and achieve non-cooperative 3D reconstruction efficiently.     

Gnutella协议的研究

Gnutella是一种用于分布式搜索的协议。尽管Gnutella协议支持传统的客户端／集中的服务器查找模式,但Gnutella的区别在于它支持对等、分散的模式。在这个模式中,第一个客户端都是服务器,同时每一个服务器也是客户端,被称为Gnutella Servents。对Gnutella协议进行了深入的分析,并用Java实现了一个Gnutella协议的核心类库。     

分布式动态一致性非线性目标跟踪策略研究

针对集中目标跟踪和分层目标跟踪中心节点通信瓶颈以及容错性能差的不足, 提出了一种分布式动态一致性非线性目标跟踪策略。目标状态初始化由网络节点采用加权最小二乘法完成。整个跟踪过程采用动态成簇策略, 分阶段选择并唤醒任务节点检测目标并执行分布式一致性扩展卡尔曼滤波策略完成目标的状态估计, 其余节点进入休眠状态从而能降低系统的能耗。从跟踪误差和能量两个方面, 与集中目标跟踪算法相比, 仿真结果表明所提算法与集中卡尔曼滤波相比, 跟踪精度相当, 适用于要求高可靠度的非线性跟踪。此外分布式的工作方式使得节点仅需与邻居交换数据并在局部完成状态估计, 消除集中式结构中心节点的瓶颈, 以保证部分传感器节点的损坏不会影响到全局任务的完成。     

一种改进的多视图聚类集成算法

近年来,针对大数据的数据挖掘技术和机器学习算法研究变得日趋重要。在聚类领域,随着多视图数据的大量出现,多视图聚类已经成为了一类重要的聚类方法。然而,大多数现有的多视图聚类算法受算法参数设置、数据样本等影响,具有聚类结果不稳定、参数需要反复调节等缺点。基于多视图K-means算法和聚类集成技术,提出了一种改进的多视图聚类集成算法,其提高了聚类的准确性、鲁棒性和稳定性。其次,由于单机环境下的多视图聚类算法难以对海量的数据进行处理,结合分布式处理技术,实现了一种分布式的多视图并行聚类算法。实验证明,并行算法在处理大数据时的时间效率有很大提升,适合于大数据环境下的多视图聚类分析。     

数字图书馆中分布式异构数据库信息检索模型的研究与实现

本文根据当前我国数字图书馆分布式异构特点带来的检索问题,提出了基于CORBA中间件的分布式异构信息检索模型,并对解决方案中的四大部分-IDL映射、数据字段统一映射、服务器端服务对象和客户端调用服务过程作了详细的分析与实现。     

多视图融合TextRCNN的论文自动推荐算法

传统论文自动推荐算法仅从单视图角度实现分类,缺乏特征融合及多视图语义知识,上下文信息和长距离依赖利用不明显,较难挖掘到深层次文本特征,从而限制学术论文推荐的准确度。针对这些问题,提出了一种基于多视图融合TextRCNN的论文自动推荐模型,该模型融合论文标题、关键词和摘要三个视图特征,利用卷积神经网络(CNN)、双向长短时记忆网络(BiLSTM)和注意力机制构建模型,实现对不同学科方向论文的自动分类及推荐。实验结果表明,设计的论文推荐模型在精确率、召回率和F₁值上均有所提升,比机器学习方法平均提高3.40%、3.57%和3.49%,也优于单视图和已有经典的深度学习方法。该方法有效利用多视图知识和上下文语义信息,提高论文推荐的准确率,进而节约科研工作者检索所需论文所花费时间和精力,进一步提高科研人员的效率,推荐符合其研究需求的学术论文,具有良好的学术价值和应用扩展。     

面向目标跟踪的混合WMSN设计与实现

设计了一个面向目标跟踪的混合无线多媒体传感器网络,主要实现了低功耗的无线图像传感器节点、无线温度传感器节点和服务器软件。对节点和单Sink下的网络性能进行了测试。结果表明：相比较于Cyclops和MeshEye,无线图像传感器节点的处理速度分别从8 MHz和55 MHz提高到240 MHz;处理器工作在188 MHz时的能耗是52.7 mA,低于Imote在104 MHz时的66 mA工作电流;当错包率接近0时,网络实际带宽约36 kb/s;基于Shape Matching的目标跟踪数据处理策略有效地降低了能量消耗。     

Optimal Kalman filtering fusion with cross-correlated sensor noises

When there is no feedback from the fusion center to local sensors, we present a distributed Kalman filtering fusion formula for linear dynamic systems with sensor noises cross-correlated, and prove that under a mild condition the fused state estimate is equivalent to the centralized Kalman filtering using all sensor measurements, therefore, it achieves the best performance. Then, for the same dynamic system, when there is feedback, a modified Kalman filtering fusion with feedback for distributed recursive state estimators is proposed, and prove that the fusion formula with feedback is, as the fusion without feedback, still exactly equivalent to the corresponding centralized Kalman filtering fusion formula; the various P matrices in the feedback Kalman filtering at both local filters and the fusion center are still the covariance matrices of tracking errors; the feedback does reduce the covariance of each local tracking error.     

大型三维几何模型在分布式协同设计中实时传输的关键技术

针对网络环境和分布式协同设计的实时性要求，在充分对比CAD模型和三角网格模型特性的基础上，提出了基于三角网格模型进行分布式协同设计，并讨论大型网格模型实时传输的关键技术，以有效的多分辨率模型为基础，在客户机／服务器环境下通过增量传输、选精化和特征映射，实现客户端驱动的产品3D模型的远程实时动态观察和特征参数的在线讨论与修改，系统可跨平台支持多个异地设计节点协同。     

Object and process migration in a single-address-space distributed system

In a distributed system framework, program interactions can be modelled by using typed objects according to client/server relationships. The operations defined by a given type are the services that may be provided by an object of this type to a client process. When the process and the object are located in different nodes, migrations may represent valid alternatives to remote procedure calls. Migration of the server object causes the memory area storing the internal representation of this object to be copied into the node of the client process. Migration of the client process causes execution of this process to proceed in the node of the server object. This paper proposes migration paradigms with reference to a memory environment implementing the notion of a single address space. The discussion takes a number of salient issues into consideration, including performance, memory configurations for object storage, and the strategies for memory management.     

分布式空间数据库中基于事务的客户端高速缓存技术研究

空间数据通过Intranet或Internet从服务器传送给客户端，由于涉及到大量的空间数据，繁重的网络传输可能成为系统的瓶颈。客户端高速缓存技术能较好的解决这个问题。论文提出了客户端缓冲技术应用在分布式空间数据系统中的体系结构；研究了基于重叠区域的客户端缓冲技术在分布式空间数据库中具体应用。并给出适合空间数据特点的缓冲置换算法；同时讨论了高速缓存技术相关高速缓冲一致性问题。     

分布式协作模型及应用研究

With the development of the Web technology,the application environment has acquired many new characters such as dynamic, openness,distribution and information uncertainty.The processing mode of application systems is more complicated than ever.For example,it requires application systems to have more community processing ability,interactive ability,distributed processing ability and collaborative ability.Accordingly the research and development of the computer application system transited from client/server information processing system into distributed collaborative processing system based on Web.Especially in the environment where the information and resources are highly distributed,the accomplishment of complicated tasks is dependent more on the resources coordination,information sharing and coordinator collaboration.The collaboration is one aspect of the group behavior and its goal is to provide a optimal method to utilize the resource through the information interaction and to solve the task which couldn't be accomplished by each coordinator alone and get the more total benefits than the sum of each benefit.The collaboration problem is the important one for distributed tasks processing.This paper surveys,the research and application status of distributed collaborative models and several representative architectures of distributed collaborative processing are proposed.However,the existing problems and the future researching direction are presented.