A framework for early design and prototyping of service-oriented applications with design patterns

Service-oriented computing is playing an important role in several domains. Today the biggest shift in mainstream design and programming is toward service-oriented applications. However, the service paradigm raises a bundle of problems that did not exist in traditional component-based development where abstraction, encapsulation, and modularity were the only main concerns. Due to their distributed, dynamic, and heterogeneous nature, service-oriented software applications require us to discover, document, and share new design patterns at the service- and architecture-level. Moreover, service-oriented applications are hard to design and validate, and demand for new foundational theories, modeling notations and analysis techniques.In line to such a vision, this article presents a framework, called SCA-PatternBox, to design and prototype service-oriented applications with design patterns. The framework relies on the OASIS standard Service Component Architecture (SCA) and on SCA component implementation types, such as SCA-Java, for supporting an “implementation-oriented” approach to service-oriented architecture modeling and to the definition and instantiation of design patterns. Moreover, in order to provide formally verified design patterns, SCA-PatternBox allows the formal specification and analysis of the functional behavioral aspects of a design pattern using a formal service specification language called SCA-ASM (Service Component Architecture-Abstract State Machine). As major evaluation of the framework, two case studies and lessons learned are presented. A final comparison of existing design pattern languages is also reported.     

Modelling real-time applications based on resource reservations

This paper presents a strategy for the design of real-time applications relying on the resource-reservation paradigm, based on a new modelling element that describes the schedulable entities of the applications during the whole design cycle. A virtual view of this element is used first for evaluating a set of constraints that guarantee the application schedulability independently of the execution platform. Then, the element is viewed as a thread that receives the particular scheduling parameters required for a schedulable execution of the application in a specific platform. The purpose of the design process is to make both views compatible.     

面向富互联网应用的数据传输策略研究

针对富互联网应用系统需要传输较大数据量而导致速度慢这一问题,研究了一种基于上下文感知的数据传输策略,通过感知用户的浏览记录和当前行为,系统可以自动预测用户下一步对数据的需求,并充分利用用户交互过程中的网络空闲时间传输数据,以提高系统的响应性.实验结果表明,该数据传输策略大大缩短了用户的等待时间,特别是在比较复杂的场景中,效果更为显著.     

一种基于流量预测的资源动态管理算法

分析了基于有效带宽理论(effectivebandwidththeory)的静态资源分配方案的弊端。在此基础上,提出了一种基于流量预测的资源动态管理算法,并且把资源动态管理算法具体应用到QoS的区分服务(DifferentiatedService)体系中,算法在区分服务网络的边缘路由器上实现。最后,在ns 2的仿真环境下对两种算法进行了比较,试验结果证明无论在丢包率还是链路利用率上,资源动态管理算法都比静态资源分配方案有明显的优势。     

基于Jini技术的互联网计算资源共享框架

描述了一个基于Jini技术的互联网计算资源共享框架JiniFrame,JiniFrame框架把互联网环境下的机器按照功能角色分为客户机、代理机和主机3种实体,共同协作完成并行应用的求解.JiniFrarne框架的可扩展性和跨平台性得益于基于Java的Jini技术,易用性与编程灵活性得益于框架中网络节点的组织方式与灵活的编程模型,同时支持主从模式与分治模式的编程.通过对实际分布式计算任务的案例分析与实验,表明了JiniFrame框架的正确性与高效性.     

云信任驱动的物联网信息资源寻址模型

为提高物联网底层信息资源寻址效果,基于对云环境下的物联网底层寻址服务的信任度评估准则等方面的研究,改进信任驱动算法,提出一个云信任驱动的物联网信息资源寻址模型。首先,分析寻址的关键特征;然后,设计并采用特定约束条件、信任陡度函数、云信任度评估准则及信任约束系数建立寻址模型;最后,设计了一个物联网系统实例来验证该模型的有效性。实验结果表明,相比传统模型或算法,该模型有良好的底层资源寻址效果。     

基于设计模式改善EJB性能的应用研究

设计模式是被用来在特定场景下解决一般设计问题的类和相互通信的对象的描述.介绍了EJB设计模式的基本概念,分析了EJB系统的性能瓶颈.针对性能问题提出EJB设计模式优化和业务层再次分层的思想,利用J2EE提供的丰富技术平台,给出了集多种设计模式优势的整合方法,较好地改善了应用开发中的性能问题,提高了系统的扩展性和复用性,最后给出该方法的应用实例.     

基于通用量子门的量子遗传算法及应用

为加快量子遗传算法的参数更新速度,简化遗传操作步骤,提出了一种基于通用量子门的量子遗传算法（Quantum Genetic Algorithm with Universal Quantum Gate,UQGA）。该方法以通用量子门为逻辑计算单位,对染色体进行遗传操作。利用Hadamard门进行基础变换;通用量子门通过新的旋转角度函数,对各个基因位进行选择、变异操作;通过求解适应度函数,得到全局最优解;同时,算法经数学证明是收敛的。该算法应用到函数极值搜索和Iris数据集特征选择中。实验结果表明,UQGA具有较好的全局搜索和特征选择性能,尤其是在收敛速度、运算时间和分类准确率方面明显优于普通量子遗传算法和普通遗传算法。     

A novel resource scheduling algorithm for QoS-aware services on the Internet

The popularity and availability of Internet connection has opened up the opportunity for network-centric collaborative work that was impossible a few years ago. Contending traffic flows in this collaborative scenario share different kinds of resources such as network links, buffers, and router CPU. The goal should hence be overall fairness in the allocation of multiple resources rather than a specific resource. In this paper, firstly, we present a novel QoS-aware resource scheduling algorithm called Weighted Composite Bandwidth and CPU Scheduler (WCBCS), which jointly allocates the fair share of the link bandwidth as well as processing resource to all competing flows. WCBCS also uses a simple and adaptive online prediction scheme for reliably estimating the processing times of the incoming data packets. Secondly, we present some analytical results, extensive NS-2 simulation work, and experimental results from our implementation on Intel IXP2400 network processor. The simulation and implementation results show that our low complexity scheduling algorithm can efficiently maximise the CPU and bandwidth utilisation while maintaining guaranteed Quality of Service (QoS) for each individual flow.     

面向信息资源聚合的物联网智能信息中心框架

物联网技术以主动感知、智能分析和反馈控制为基本要素,实现对"物体"的识别、监控和管理,在诸多领域取得显著的应用成效,同时也暴露出应用建设分散、缺乏体系、重复建设现象严重等问题。从回顾物联网的发展历史出发,对物联网技术架构和相关工作进行分析,提出面向信息资源聚合的物联网智能信息中心框架,通过对多源、分布、异构资源的汇聚、整合、分析与再加工,为实现资源共享、提高资源利用率、解决重复建设问题提供基础性支撑,并重点讨论了传感设备的标准化封装与接入、信息资源的一体化管理等关键技术。最后,通过在农业物联网中的应用示例分析了该框架的效果。     

基于图像处理的智能通用抄表系统设计

本文提出了一种基于ARM处理器S3C2410平台和通用分组无线业务GPRS技术的智能通用抄表系统。首先介绍了系统的组成及工作原理,然后详细描述了系统通讯部分的硬件电路结构和软件设计流程。通过在实验室构建硬件平台并实现了系统设计,该系统具有很好的实用价值和广泛的应用前景。     

基于移动互联网应用的可靠数据推送方法

基于Android平台的手机应用已经越来越多了,越来越多的人使用智能手机进行查收邮件,浏览互联网网页等操作,智能手机很大程度覆盖了电脑的功能,给人们带来很多方便之处,如灵活性：智能手机相对于电脑来说,具有轻便的特点,十分适合携带;娱乐性,智能手机拥有各式各样的传感器,利用这些传感器可以实现指南针,翻转关闭闹钟等功能;央时性,通过网络运营商,智能手机可以随时随地连接互联网,消息更具有实时性、然而,对于所有移动应用开发商而言都会面临一个问题．那就是如何对已经发布的应用使用状态、使用频率做统计,如果应用有新版本发布了,如果通知到用户手机终端呢？如何可靠、即时的将系统中通知消息推送到移动终端上,是一个十分关键的问题。     

Reusable generic design patterns for mixed-criticality systems based on DREAMS

Multi-core mixed-criticality systems are complex solutions that provide benefits regarding lower power consumption, size, weight and cost and better performance and scalability, compared with single-core architectures. However, these systems where virtualization mechanisms such as hypervisors are used for integrating functionalities with different criticality levels into the same hardware platform and where on-chip and off-chip communication systems are implemented for communicating, imply certification challenges due to their complexity. Those challenges to certification are supported by the fact that today’s safety-related standard focus on single computing systems where spatial and temporal interferences are quite probable. Multi-core architectures enable sharing resources (e.g., cache memory, I/Os) between more than one processor at the same time, facilitating the appearance of interferences which may hinder the achievement of the spatial and temporal independences.This paper analyses the certification challenges in mixed-criticality systems and identifies some reusable generic solutions to overcome those challenges. The solutions presented in this paper are integrated into a safety wind turbine system that follows the design style introduced in European project DREAMS.     

Adapting multimedia Internet content for universal access

Content delivery over the Internet needs to address both the multimedia nature of the content and the capabilities of the diverse client platforms the content is being delivered to. We present a system that adapts multimedia Web documents to optimally match the capabilities of the client device requesting it. This system has two key components. 1) A representation scheme called the InfoPyramid that provides a multimodal, multiresolution representation hierarchy for multimedia. 2) A customizer that selects the best content representation to meet the client capabilities while delivering the most value. We model the selection process as a resource allocation problem in a generalized rate distortion framework. In this framework, we address the issue of both multiple media types in a Web document and multiple resource types at the client. We extend this framework to allow prioritization on the content items in a Web document. We illustrate our content adaptation technique with a web server that adapts multimedia news stories to clients as diverse as workstations, PDA's and cellular phones     

基于AMTrix的Internet EDI系统设计及实现

基于Internet的EDI是实现电子商务的一种关键技术。介绍了电子商务的分类，探讨了EDI单证的处理过程、基于internet的EDI系统结构、应用广泛的EDI开发平台AMTrix，同时也分析了基于internet的EDI系统实现所需要的关键技术。     

RPCI：面向互联网的RPC框架

RPC是互联网后端分布式系统的核心组件,能够降低互联网应用开发、运维成本,提高可用性和可扩展性,但是目前流行的RPC框架不能完全满足互联网应用需求。分析了互联网应用环境下RPC系统的需求,并针对需求提出了面向互联网的RPC系统RPCI。RPCI采用三层架构,将长连接服务器独立出来,以支持无状态应用服务器设计和灵活的请求路由策略,使得系统扩容、升级、运维更加容易。基于thrift实现了RPCI,优化了性能,实验结果表明,RPCI性能优秀,相比常用开源软件thrift性能提升50％以上。     

A taxonomy of multicast protocols for Internet applications

The continuous growth in applications that require communications among a group of hosts or simultaneous dissemination of data to multiple sites on the Internet has led to considerable interest in multicast communication. These applications have different quality of service requirements such as deadlines to response time and tolerance to data loss. Internet multicast protocols provide a spectrum of services to cater for the needs of a wide array of multicast applications. The design alternatives of a multicast protocol for a particular application may lead to different performance characteristics, for example higher utilization of network bandwidth vs lower protocol processing requirements. Therefore a framework is required to various design choices available to design multicast protocols and evaluate the performance tradeoffs associated with these alternatives. Motivated by such a need and by the evolution of multicast applications over the Internet, this article presents a taxonomy of multicast protocols and a common framework to evaluate their performance.     

A design methodology for data-parallel applications

A methodology for the design and development of data-parallel applications and components is presented. Data-parallelism is a well understood form of parallel computation, yet developing simple applications can involve substantial efforts to express the problem in low level notations. We describe a process of software development for data-parallel applications starting from high level specifications, generating repeated refinements of designs to match different architectural models and performance constraints, enabling a development activity with cost benefit analysis. Primary issues are algorithm choice, correctness, and efficiency, followed by data decomposition, load balancing, and message passing coordination. Development of a data-parallel multitarget tracking application is used as a case study, showing the progression from high to low level refinements. We conclude by describing tool support for the process