基于事务对象的RPC技术应用

该文简要介绍了事务、事务对象、存储过程、远程过程调用等概念。以PB为背景,提出了提高数据访问速度、加快程序运行的三种方法,即:游标、直接存储过程调用、事务对象远程过程调用。并通过实例验证应用事务对象的远程过程调用方法可以极大地提高数据访问速度。     

RMI分布式技术在气象信息处理系统中的应用

该文阐述了气象信息处理系统应用的必要性,论述了RMI在分布式系统中实现远程方法调用的优越性,并对RMI技术的工作原理进行了介绍,详细叙述了如何在气象信息处理系统中创建一个RMI应用。     

基于事务对象的远程过程调用

介绍了事务、事务对象、存储过程、远程过程调用等概念。然后说明了如何提高 数据访问速度的3种方法。通过比较，得出了利用事务对象对远程服务器上的存储过程进行 调用具有运行速度快的特点。     

RMI的分布式对象技术研究

随着网络的发展,分布式对象技术已成为主要的远程调用机制并被应用于各种分布式系统。本文详细讨论了远程方法调用RMI中所定义的远程对象的基本结构、远程调用机制、关键技术及其技术特性,并比较了它与其它两种分布式对象技术COM和CORBA的不同。     

基于分布对象的异步消息模型研究

分布对象技术发展迅速,其中一个重要的原因就是它能够为client提供一种有效的远程方法调用手段。虽然传统分布对象技术提供了一种同步、紧耦合的远程方法调用模型,但这种模型并不能满足异步特征的需要。提出一种基于分布对象的异步消息模型,重点对其两种异步的远程方法调用模型进行了定义、分析和研究。     

Web Services的对象封装技术

在研究DCOM远程对象调用的基础上,提出了一个基于对象远程过程调用的W ebServices实现方式,实现了W eb Services的远程对象访问。该实现方法不仅可以同一般的W ebServices访问方式兼容,而且在需要客户验证的情况下,可以有效减少客户验证和网络负担,还能减小客户验证信息被攻击的风险。     

基于CORBA的容错对象复制算法

描述了一种基于CORBA远程对象调用机制的容错对象复制算法，它采用primary-backup复制机制，客户方主动参与容错，能够重新调用请求并保证at-most-once语义，实现了复制协议与可靠通信协议的分离，所采用的容错机制对用户完全透明，而且通过在自主研制的分布计算平台StarBus上的实现，对该算法进行了验证。     

PASCAL远程调用参数的组织

本文介绍了支持ＴＵＲＢＯ－ＰＡＳＣＡＬＶ．６．０远程调用系统中远程单元过程调用参数的规范化组织。这种规范化组织包括调用参数消息的描述，组织远程单元过程调用参数的数据结构，过程调用参数的装配     

CORBA的分布式处理机制

随着CORBA技术在各个领域应用的扩展,许多开发人员迫切希望了解CORBA对象分布计算的细节,从而提高系统开发的效率,针对这种需要,文中参照RPC的3层体系结构,从基本编程结构,远程调用结构和底层通信结构3个层面揭示了CORBA内部的分布式处理机制,最后系统总结了CORBA这种面向对象的远程过程调用结构。     

CORBA:全面的分布式对象计算(上)

CORBA（CommonObjectRequestBrokerArchitecture）是建立在面向对象基础上的分布式对象计算体系结构,该文综述CORBA的重要概念和基本原理,包括CORBA体系结构、界面描述语言、支持远程对象调用的静态调用SII和动态调用DII以及支持DII的界面仓库。     

CORBA分布式计算环境下的本地对象访问机制

分布式计算环境下的对象按其访问方式可以分为本地对象与远程对象。高效、合理的本地对象访问是面向对象中间件所需解决的关键问题。本文在对CORBA中典型的本地对象访问机制进行深入分析的基础上，提出了一种符合CORBA规范的具体实现方案。这一方案具有良好的可靠性和可扩展性。     

An experimental object-based sharing system for networked databases

An approach and mechanism for the transparent sharing of objects in an environment of interconnected (networked), autonomous database systems is presented. An experimental prototype system has been designed and implemented, and an analysis of its performance conducted. Previous approaches to sharing in this environment typically rely on the use of a global, integrated conceptual database schema; users and applications must pose queries at this new level of abstraction to access remote information. By contrast, our approach provides a mechanism that allows users to import remote objects directly into their local database transparently; access to remote objects is virtually the same as access to local objects. The experimental prototype system that has been designed and implemented is based on the Iris and Omega object-based database management systems; this system supports the sharing of data and meta-data objects (information units) as well as units of behavior. The results of experiments conducted to evaluate the performance of our mechanism demonstrate the feasibility of database transparent object sharing in a federated environment, and provide insight into the performance overhead and tradeoffs involved. Edited by Georges Gardarin. Received October 29, 1992 / Revised May 4, 1994 / Accepted March 1, 1995     

Experience with distributed Smalltalk

Distributed Smalltalk (DS) is an implementation of Smalltalk that supports the interaction of many Smalltalk users on many machines. It provides communication and interaction among remote Smalltalk users, direct access to remote objects, and a degree of object sharing among users. The distributed aspects of the system are largely user transparent. Many of the major design issues and implementation decisions associated with Distributed Smalltalk have previously been reported. This paper concentrates on the impact of those decisions and describes how DS is used to build distributed applications. Three example applications are described: remote file access, animated distributed objects, and offloading a compute-intensive task to a non-Smalltalk host. Based on our experience with DS, we present an evaluation of its design and implementation.     

Java based replicated server objects and their remote method invocations in a distributed environment

A distributed system is said to be fault‐tolerant if it is able to provide important services despite partial failures of the computers or software objects in the system. These systems are needed to support applications such as remote access and control, virtual mobile offices and wide area collaborative systems where there are chances of failures in the network and software objects. Fault‐tolerance is usually achieved by replicating the objects in the system. Traditional distributed applications constructed using Java RMI (remote method invocation) are not fault‐tolerant because of the lack of support of object replication. The objective of the present work is to design a remote method invocation that supports server object replication. To provide a fault‐tolerant service to the remote client objects, server objects are actively replicated. The problems associated with the method invocation in the context of active server object replication are presented and solutions are discussed and implemented. Copyright © 2001 John Wiley & Sons, Ltd.     

无线接入技术及其在远程故障诊断中的应用研究

首先介绍了现有主要的无线接入技术的特点及其相关适用对象，重点讨论了LMDS和移动互联网技术，然后结合具体应用对象，给出了一个采用无线接入技术的远程故障诊断系统实现方案。     

一种支持网上共享设备的安全模型

分析和比较了传统访问控制模型中客体与共享设备资源的异同，指出了设备资源具有时间依赖性、权限差异性、容量受限和进程依赖性，并根据共享设备资源的特性要求，在基于角色的访问控制模型的基础上引入了动态执行者、固定角色和设备访问控制策略等概念，提出了一种远程设备访问控制模型(RDAC)，更好地实现了对设备的描述和访问控制。     

一种基于PERMIS PMI的安全访问控制的设计

为实现某型装备远程维修技术支援系统中资源的访问控制,保证系统数据安全,设计了基于PERMISPMI的安全访问控制方法,通过对业务层的合理构建和对主体、客体以及相应动作的访问控制策略配置,实现了由角色代替用户对资源进行访问。实践证明,基于PERMIS PMI的访问控制方法在系统中起到了良好的作用并降低了维护工作的强度。     

基于运动检测的远程图像采集系统的设计与实现

文章设计了一种基于运动检测的FPGA远程图像采集与存储系统,并给出了系统整体设计方案和核心的运动检测模块的具体实现方法。该系统主要由图像采集模块,运动检测模块,图像存储模块以及网络接入模块组成。该设计在FPGA多媒体开发平台EP2C70的基础上添加基于LAN91C111的网络接入模块来实现,利用Verilog语言在该平台上具体实现运动检测算法。试验证明该系统可以快速并智能化采集图像信息,快速的检测异常运动物体,采集的图像信息被实时存储或者通过网络接入模块实现远程传输。     

A content-based authorization model for digital libraries

Digital libraries (DLs) introduce several challenging requirements with respect to the formulation, specification and enforcement of adequate data protection policies. Unlike conventional database environments, a DL environment is typically characterized by a dynamic user population, often making accesses from remote locations, and by an extraordinarily large amount of multimedia information, stored in a variety of formats. Moreover, in a DL environment, access policies are often specified based on user qualifications and characteristics, rather than on user identity (e.g. a user can be given access to an R-rated video only if he/ she is more than 18 years old). Another crucial requirement is the support for content-dependent authorizations on digital library objects (e.g. all documents containing discussions on how to operate guns must be made available only to users who are 18 or older). Since traditional authorization models do not adequately meet the access control requirements typical of DLs, we propose a content-based authorization model that is suitable for a DL environment. Specifically, the most innovative features of our authorization model are: (1) flexible specification of authorizations based on the qualifications and (positive and negative) characteristics of users, (2) both content-dependent and content-independent access control to digital library objects, and (3) the varying granularity of authorization objects ranging from sets of library objects to specific portions of objects     

Determining the number of remote sites accessed in distributedtransaction processing

The number of remote accesses and the number of distinct remote sites accessed by global transactions in a distributed database environment are characterized. Both measures are important in determining the overhead of distributed transaction processing and are affected by the distribution of transaction size (number of distinct objects accessed by a transaction) and the distribution of remote accesses made by a transaction. Keeping the mean transaction size fixed, it is shown that in the case of some commonly used distributions for the number of remote accesses variable size transactions access fewer distinct remote sites on the average than fixed size transactions. Also, for these and some other distributions the mean number of remote accesses is independent of the distribution of transaction size, but this is not generally true