大型分布式管理信息系统的安全问题研究*

从计算机和网络安全的角度出发,以构建大型分布式管理信息系统为背景,首先阐述系统的结构和安全需求;在此基础上分析了系统可能面临的安全风险;最后从技术和管理两个方面提出了相关的安全策略.     

Issues,Responsibilities and Identities: A Distributed Leadership Perspective on Biotechnology R&D Management

The aim of the research reported here is to contribute to the ongoing development of R&D project leadership studies by applying a distributed leadership perspective in the analysis of a product development project in a small biotechnology venture. A distributed leadership perspective implies that leadership is studied as a process of social interaction, involving several individuals who continuously construct leadership activities together. From a case study of a bio‐tech venture, we conclude that leadership work in R&D projects implies construction of issues, responsibilities and identities. That is, what people do – seen from this perspective – when performing leadership activities in this project is that they gradually move the project and the organization forward by processing issues, resolving ambiguities concerning responsibility, and develop their understandings on the identity bases involved.     

影响分布式控制系统性能的若干因素

分布式控制系统(DCS)是工业控制应用技术的热点和主流.本文简要地阐述了系统体系结构的架构、时间延迟、控制网络和通讯调度等这些因素对控制系统整体性能的影响以及相关研究现状.并指出系统的、恰当的方法分析DCS的行为特性,允许系统集成人员能够快速评价多种不同方案并从中选择最佳方案而无需大量的仿真,在此基础上,对系统体系结构进行优化.这是DCS研究需要进一步深入的课题.     

Guest Editorial: Reliability Issues in Distributed Systems

TO provide continuity of operations in automated systems, we need to develop techniques that can make them reliable. Many systems such as used in space programs, air traffic control, nuclear plant monitors, ballistic missile defense, etc., demand robust operation. In the past, research efforts have focused on the design and implementation of distributed systems used in such applications. We foresee a need of research effort in the investigation of algorithms and system structures that make error/failure detection, reconfiguration, recovery, and restart of a system feasible with the least amount of interruptions.     

分布式系统的管理

系统管理在分布式系统中有着举足轻重的地位。系统管理和分布式系统管理的定义可以从计算机系统和计算机环境的关系中得到。按照计算机系统的发展历史，计算机的系统管理模式可分为四类：集中式、分散式、网络式、分布式。分布式系统的管理模式介于分散式和集中式之间。系统管理的任务分为五类：用户管理、任务管理、软件管理、硬件管理和网络管理。每一类管理又有五个子任务：配置管理、性能管理、失效管理、安全管理和资源管理。客户／服务器模式在分布式系统中有了新的策略。针对分布式系统中存在的问题，出现了一些有效的解决技术。在这一领域中还出现了两个管理的范例：开放软件基金会（ＯＳＦ）的分布式管理环境（ＤＭＥ）和简单网络协议（ＳＮＭＰ）。     

分布式工作流的动态管理

近些年来 ,分布式工作流管理系统设计已经成为计算机学者的研究热点。传统的工作流管理系统大多建立在客户机 /服务器模式上 ,采用集中式的方式。虽然易于实现、维护和管理 ,却存在着系统可扩展性、集成性差 ,产品可靠性、可用性不高 ,安全性能低的显著缺陷。采用分布式策略将工作流系统功能离散化或模块化 ,通过各个模块间的相互协调工作 ,实现预定功能 ,其优点在于能适应大吞吐量的要求、可扩展性高、可靠性强。然而 ,在现代企业管理中 ,由于流程模式改进、客户需求改变等原因迫使流程经常发生变迁。其必须在工作流结构中及时得到反映 ,这就使得动态管理技术在分布式工作流显得必不可少。将从建模、体系结构、运行环境、动态重组几个方面对分布式工作流的动态管理技术进行介绍和探讨。     

Distributed Knowledge Management in eLearning

With the wide application of Internet in elearning, the requirement of reusable, sharable learning objects and adaptive learning strategies becomes common ground. Traditional methods of Web resources publishing and managing such as free publishing or building application systems for special purposes are not good at fast discovering and aggregating knowledge. This paper discusses Meta-data structure in elearning, which facilitates searching, managing and linking granules of learning contents. Applying Web services and UDDI techniques, a system of knowledge management on Web based on Meta-data is proposed and some questions in application are discussed.     

Trust Management in Distributed Systems

Distributed systems such as the Internet, peer-to-peer networks, and mobile ad hoc networks involve numerous entities, many of which haven't previously interacted. Trust management can help minimize risk and ensure the network activity of benign entities in distributed systems. This article presents different trust models. It also discusses trust management in P2P system     

Issues and Techniques in Networked-Based Distributed Healthcare: Overview

For telemedicine to reach its potential in the Internet2 environment,significant progress must be made in a number of areas. The emergingtelecommunications will include the Internet2 between medicalinstitutions and emerging broadband loop and wireless technologiesfor interconnections to homes. Within the technical environment,problems that must be addressed include the development of robotic-controlled,remote-monitoring devices unique to the various medical specialties;the encoding, transmission, and decoding of raw data specificto the specialized needs of various medical application areas;and the reduction of data for storage and retrieval in patientrecords. Institutionally, human factor and information accessissues with respect to physicians, patients, and non-physicianhealthcare providers must be addressed; healthcare insuranceprovider policies, government regulation, and state licensinglaws must be adapted for a new paradigm of healthcare delivery;and the philosophy of capital investment for the delivery ofhealthcare must be revised.Many current practiceswill be supplanted by home healthcare alternatives, the use ofpatient-initiated preventive healthcare initiatives, and remote-clinicactivity. These applications will result in central record archivingsystems; the need for encryption schemes, virus protection, andvandalism protection; extensive, additional connectivity betweenhealthcare providers and professionals; and new commercial playersin the healthcare arena.The hot applicationareas will include women's health, children's health, healthcarefor senior citizens, home healthcare, well-patient monitoring,and early-detection of medical problems.     

松耦合分布式网络管理

本文提出了一种松耦合的分布式网络管理体系结构,该结构使用XML／SOAP将多个紧密耦合系统连接起来,实现对大型网络的管理,并对实现技术进行了讨论。     

基于委任的分布式网络管理

介绍基于委任的分布式网络管理技术和基于委任的分布式网络管理的具体实现，克服了传统的集中式网络管理系统管理大规模异构网络的缺陷。     

分布式元数据管理

当前的元数据管理都是倾向于集中式管理,并且依赖于使用集中的元数据仓库,这种方法虽然在OLTP系统中取得了一定成功,但是在数据仓库环境中,却收效甚徽.因此,建立一个新的分布式元数据管理体系是十分必要的.     

基于SOAP的分布式网络管理

提出了一个基于SOAP的分布式网络管理模型，通过在网络设备中嵌入SOAP务器使得此网络设备成为一个服务提供者、服务请求者。通过采用SOAP，可以看到这种模型在分布式网络管理中的种种优势。     

异构分布式环境下的约束管理问题

1 引言随着网络技术的发展,蕴藏巨大信息的网络可以被视为存储信息的数据库,但这种分布式环境要求具有更有效、复杂的信息处理能力。当数据存储在网络上松耦合、异构的系统中,彼此又存在联系时,就产生了数据的完整性约束问题。例如,虚拟企业为物理上分布的结点提供高度的交互空间,以便于这些事先存在     

开放分布式系统中的信任管理

随着Internet的发展,分布式计算成为发展的主流,涌现出许多新的分布式计算模式。传统的访问控制机制不能很好地适用于这些系统。该文在分析传统的基于证书的信任关系模型和访问控制机制后,深入分析了几个有名的信任管理系统,讨论了目前存在的问题和今后的研究方向。     

分布式空间数据管理技术研究

对分布式空间数据库管理的有关技术问题进行了探讨,对商业软件Oracle及ESRI系列的分布式空间数据管理功能进行了分析,最后提出了建立分布式空间数据应用系统的一种实用策略。