Implementation of a TMO‐structured real‐time airplane‐landing simulator on a distributed computing environment

In real‐time simulation, the simulated system should display the same (or very close) timing behavior as the target system. The simulation accuracy is increased as the simulation time unit is decreased. Although there are several models for such systems, the TMO model is particularly appropriate due to its natural support for real‐time distributed object‐oriented programming. This paper discusses the results of the implementation of a real‐time airplane‐landing simulator on a distributed computing environment using the TMO model. Copyright © 2004 John Wiley & Sons, Ltd.     

基于QEMU RISC-V架构的OpenHarmony标准系统移植

RISC-V指令集架构的诞生促进了RISC-V硬件平台的快速发展,因此,在RISC-V架构硬件平台上运行高效且易于使用的操作系统需求日益增加.面向分布式、开源开放的智能终端操作系统OpenHarmony技术正在不断演进,其生态持续繁荣.然而,将OpenHarmony适配到RISC-V指令集架构平台上面临新的挑战,包括软件栈和芯片移植的问题. RISC-V指令集架构平台的软件栈和芯片移植存在新的挑战.本文提出了基于RISC-V QEMU平台的OpenHarmony标准系统移植的思路和方法,通过对关键软件栈进行适配和在QEMU RISC-V虚拟化硬件平台上移植图形显示驱动,成功实现了OpenHarmony标准系统在QEMU RISC-V虚拟化硬件平台上的正常启动,并进入系统桌面.该成果为开发者提供了在RISC-V平台上测试应用OpenHarmony标准系统的平台,并为新的RISC-V硬件平台上移植OpenHarmony标准系统提供了参考.     

Towards multilaterally secure computing platforms—with open source and trusted computing

We present a security architecture for a trustworthy open computing platform that aims at solving a variety of security problems of conventional platforms by an efficient migration of existing operating system components, a Security Software Layer (PERSEUS), and hardware functionalities offered by the Trusted Computing technology. The main goal is to provide multilateral security, e.g., protecting users' privacy while preventing violations of copyrights. Hence the proposed architecture includes a variety of security services such as secure booting, trusted GUI, secure installation/update, and trusted viewer. The design is flexible enough to support a wide range of hardware platforms, i.e., PC, PDA, and embedded systems. The proposed platform shall serve as a basis for implementing a variety of innovative business models and distributed applications with multilateral security.     

QoS customization in distributed object systems

Applications built on networked collections of computers are increasingly using distributed object platforms such as CORBA,Java Remote Method Invocation (RMI), and DCOM to standardize object interactions. With this increased use comes the increased need for enhanced quality of service (QoS) attributes related to fault tolerance, security, and timeliness. This paper describes an architecture called CQoS (configurable QoS) for implementing such enhancements in a transparent, highly customizable, and portable manner. CQoS consists of two parts: application‐ and platform‐dependent interceptors and generic QoS components. The generic QoS components are implemented using Cactus, a system for building highly configurable protocols and services in distributed systems. The CQoS architecture and the interfaces between the different components are described, together with implementations of QoS attributes using Cactus and interceptors for CORBA and Java RMI. Experimental results are given for a test application executing on a Linux cluster using Cactus/J, the Java implementation of Cactus. Compared with other approaches, CQoS emphasizes portability across different distributed object platforms, while the use of Cactus allows custom combinations of fault‐tolerance, security, and timeliness attributes to be realized on a per‐object basis in a straightforward way. Copyright © 2003 John Wiley & Sons, Ltd.     

基于CORBA的分布式信息交换处理系统模型

讨论了分布对象技术在大型分布式企业计算环境中的应用,给出了分布式信息交换处理系统的软件体系结构和模型实现。传统的大型分布式企业计算环境具有如下应用特征：异构平台繁多、存在多种遗留应用、大量业务应用系统不能实现透明的互联互操作。针对上述特征,系统采用当前分布对象技术中的主流－CORBA技术,设计与实现了一个分布式信息交换处理集成平台,为企业内部繁多的业务应用系统提供了一个应用集成框架,将企业内各类复杂的计算资源集成为一个有机的整体。     

Linux: Alternative Directions in Computing

Although fairly new on the computing scene, Linux has gained an exceptional reputation as a stable and robust operating system platform. in fact, the stability of the platform parallels or exceeds similar operating environments that are available from commercial operating system vendors. This article examines options for introducing Linux into a business environment as well as the opportunities to embrace this new and exciting platform in the world of enterprise computing.     

异构处理器多操作系统协同技术研究

随着嵌入式设备应用场景日趋复杂的变化,异构多核架构逐渐成为嵌入式处理器的主流架构.目前,多核处理器主要采用的单操作系统模式在实际应用中存在诸多局限性.为了充分发挥异构处理器的多核特性,针对异构处理器不同核部署相应的操作系统并实现多操作系统协同处理技术至关重要.本文对异构多核处理器（ARM+DSP）操作系统进行了研究,在异构多核平台上成功移植了嵌入式Linux和国产DSP实时操作系统ReWorks;为实现ReWorks与Linux操作系统协同处理,本文对核间通信的关键技术进行分析研究,并以TI公司的AM5718为例,设计了一系列多核异构通信组件.经测试,本文设计的异构通信组件实现了在ARM上对DSP核进行ReWorks操作系统和应用程序的动态加载、Linux与ReWorks核间消息收发、以及Linux与ReWorks的协同计算等功能.     

A new fuzzy-decision based load balancing system for distributed object computing

Distributed object computing systems are widely envisioned to be the desired distributed software development paradigm due to the higher modularity and the capability of handling machine and operating system heterogeneity. Indeed, enabled by the tremendous advancements in processor and networking technologies, complex operations such as object serialization and data marshaling have become very efficient, and thus, distributed object systems are being built for many different applications. However, as the system scales up (e.g., with larger number of server and client objects, and more machines), a judicious load balancing system is required to efficiently distribute the workload (e.g., the queries, messages/objects passing) among the different servers in the system. Unfortunately, in existing distributed object middleware systems, such a load balancing facility does not exist. In this paper, we present the design and implementation of a new dynamic fuzzy-decision-based load balancing system incorporated in a distributed object computing environment. Our proposed approach works by using a fuzzy logic controller which informs a client object to use the most appropriate service such that load balancing among servers is achieved. We have chosen Jini to build our experimental middleware platform, on which our proposed approach as well as other related techniques are implemented and compared. Extensive experiments are conducted to investigate the effectiveness of our fuzzy-decision-based algorithm, which is found to be consistently better than other approaches.     

CORBA与DCOM的比较

分布对象计算是分布式计算系统的最新发展方向，而ＣＯＲＢＡ和ＤＣＯＭ则是其中最重要的两种系统的模型。     

一个基于CORBA的图形用户界面体系结构及实例

随着网络计算技术的发展,软件的结构变为表示／处理／数据库分离的三级模式。表示与处理的分离导致了用户界面与应用计算间的通信成为开发交互式系统图形用户界面的关键。本文为分布式交互图形应用的开发提供了一个基于公用对象需求代理结构ＣＯＲＢＡ的用户界面体系结构,ＣＯＲＢＡ是为分布式对象系统中间件制定的一个互操作标准。在这个结构中,一些被称为代理的面向对象交互式图形构件被设计用来为图形的表示与交互提供有效的解     

分布式计算平台上的Web应用系统体系结构

首先讨论了网络运算结构由早期的集中式结构发展到主从结构 ,最后过渡到分布式结构的演变过程 ,阐明了微软推出的分布式计算环境—— Active平台的结构和特点 ,最后研究了构筑在这种分布式计算平台上 ,由表示层、功能层、数据层构成的 Web应用系统的体系结构 ,并描述了相应的开发环境和开发技术。     

Computing in the RAIN: a reliable array of independent nodes

The RAIN project is a research collaboration between Caltech and NASA-JPL on distributed computing and data-storage systems for future spaceborne missions. The goal of the project is to identify and develop key building blocks for reliable distributed systems built with inexpensive off-the-shelf components. The RAIN platform consists of a heterogeneous cluster of computing and/or storage nodes connected via multiple interfaces to networks configured in fault-tolerant topologies. The RAIN software components run in conjunction with operating system services and standard network protocols. Through software-implemented fault tolerance, the system tolerates multiple node, link, and switch failures, with no single point of failure. The RAIN-technology has been transferred to Rainfinity, a start-up company focusing on creating clustered solutions for improving the performance and availability of Internet data centers. In this paper, we describe the following contributions: 1) fault-tolerant interconnect topologies and communication protocols providing consistent error reporting of link failures, 2) fault management techniques based on group membership, and 3) data storage schemes based on computationally efficient error-control codes. We present several proof-of-concept applications: a highly-available video server, a highly-available Web server, and a distributed checkpointing system. Also, we describe a commercial product, Rainwall, built with the RAIN technology     

汽车计算平台中信息系统的架构

汽车计算平台就是指通过车内网络通信技术,依靠高性能集成计算技术和高可信软件技术,基于高性能CPU芯片和嵌入式实时操作系统构建整车的集中计算控制核心.通过在FreeScale的Total5200和嵌入式Linux系统之上,创建基于OSGi规范的信息系统,完成各汽车模块和远程服务系统的信息交互和信息管理.介绍信息系统的架构,并详细描述信息系统的实现.     

On Load Balancing Approaches for Distributed Object Computing Systems

Distributed object computing systems are widely envisioned to be the desired distributed software development paradigm in the near future due to the higher modularity and the capability of handling machine and operating system heterogeneity. Indeed, enabled by the tremendous advancements in processor and networking technologies, complex operations such as object serialization and data marshalling become very efficient, and thus, distributed object systems are being built for many different applications. As the system scales up (e.g., with larger number of server and client objects, and more machines), a judicious load balancing system is required to efficiently distribute the workload (e.g., the queries, messages/objects passing) among different servers in the system. Several such load balancing schemes are proposed recently in the literature. However, while the rationales and mechanisms employed are dramatically different, the relative strengths and weaknesses of these approaches are unknown, making it difficult for a practitioner to choose an appropriate approach for the problem at hand. In this paper, we describe in detail three representative approaches, which are all practicable, and present a quantitative comparison using a real experimental distributed object computing platform. Among these three approaches, namely, JavaSpaces based, request redirection based, and fuzzy decision based, we find that the fuzzy decision-based algorithm outperforms the other two considerably under a wide range of different practical scenarios.     

FPGA嵌入式系统的Linux设备驱动程序开发

基于FPGA嵌入式系统,在PowerPC架构的Linux2.6操作系统环境下,对通用输入输出接口(GPIO)控制器的驱动,采用平台设备机制进行中断控制管理.通过该管理机制,将GPIO设备本身的资源注册进内核,由内核统一管理.在参照Linux2.6内核源码有关平台设备驱动的基础上,编写和测试了GPIO设备的驱动程序.该驱...     

远程跨平台水下声场并行计算系统的实现

介绍一种跨平台远程水下声场并行计算系统。该系统支持从Windows平台到Linux平台的远程跨平台操作,为用户提供一种统一的使用模式,用户无须了解并行系统的具体结构即可使用并行系统,完成所需要的计算或仿真。应用结果表明,该系统可降低开发并行程序的复杂度,提高并行系统的使用效率,实现服务端与客户端的实时数据交换,具有很好的实用价值。     

基于Agent网格计算性能的实时调节

由于网格环境中资源的动态性、非独占性、异构性、分布性和网络通信延迟的不确定性等因素导致了应用程序的复杂和低效,难以达到预期的性能。为了实时调整和改进并行和分布式应用的性能,该文研究采用Agent技术设计一种系统模型,利用Agent收集应用各种性能参数,然后利用Agent的智能性,加以分析综合并实时调整,使应用程序更加适应网格的动态环境,获得更高的性能。     

Specification, decomposition and agent synthesis for situation-aware service-based systems

Service-based systems are distributed computing systems with the major advantage of enabling rapid composition of distributed applications, such as collaborative research and development, e-business, health care, military applications and homeland security, regardless of the programming languages and platforms used in developing and running various components of the applications. In dynamic service-oriented computing environment, situation awareness (SAW) is needed for system monitoring, adaptive service coordination and flexible security policy enforcement. To greatly reduce the development effort of SAW capability in service-based systems and effectively support runtime system adaptation, it is necessary to automate the development of reusable and autonomous software components, called SAW agents, for situation-aware service-based systems. In this paper, a logic-based approach to declaratively specifying SAW requirements, decomposing SAW specifications for efficient distributed situation analysis, and automated synthesis of SAW agents is presented. This approach is based on AS³ calculus and logic, and our declarative model for SAW. Evaluation results of our approach are also presented.     

Skylark:云端一体化系统的设计与实现

论文介绍了云端一体化系统Skylark,旨在满足用户通过异构终端,随时、随地访问应用和管理数据的需求,使得用户对操作系统平台、硬件设备、应用安装管理的依赖最小化.终端通过SkylarkAPI访问云平台的服务,基于扩展的Spice协议为显示和计算的前后端分离提供高效支持;后端云平台对计算、存储和网络等资源进行虚拟化,基于Xen-IFS文件系统分离和保护用户私有数据;SkylarkManager云管理系统整合前后端业务,对系统资源进行统一管理和调度.Skylark支持Windows、Linux和Android等多种客户端,实现了云中心和各异构终端的一体化.     

嵌入式Linux 2.6在S3C2410上的移植技术探析

移植操作系统是开发嵌入式系统的前提和基础,通过将Linux 2.6内核移植到S3C2410目标板上,提出了嵌入式Linux移植的方法与具体实现过程。编译生成的内核在嵌入式系统中运行稳定。结果证明方法可行,并对开发其它类型的嵌入式系统有一定的参考意义。