基于色彩地址空间转换与多版本策略的复杂位图协同模型与一致性维护算法

调色编辑在现有位图协同模型下存在数据发送量大、编辑灵活性差、操作重叠易冲突、生成版本多、站点存储压力大等问题,针对这些问题提出了一种面向复杂位图的调色协同编辑模型。协同操作仅发送坐标与色彩变化量的协同操作,具有数据量小、多维编辑粒度、位置可重叠等特性;增加了时空关系的四维位图协同架构,只保存已编辑的像素点数据可减少数据存储量;采用空间转换的副本状态控制算法,通过回溯重构历史版本,可以确保协同操作总是在正确的副本状态上执行;根据当前状态与策略配置,动态生成分支版本的算法,可以解决此前模型分支版本过多的问题。最后,基于CCI（causality-preservation,convergence,intention-preservation）模型进行正确性推论,开发协同编辑器原型Co-Pixel,随机生成的操作集设计实验,对照Adobe Lightroom 模拟实际编辑行为。结果显示提出的模型可有效减少操作产生冲突,降低一致性维护过程中的算法开销,灵活调整用户执行意图维护工作的结果版本。     

基于版本复制的版本存储技术研究

协同图形编辑系统中采用基于版本复制的多版本技术解决编辑过程中冲突操作的意愿保证问题．每个版本存储了在此版本上执行的所有操作,因此存在同一操作被多次存储和版本存储量随编辑过程大规模增加的情况。本文讨论了协同图形编辑系统中基于版本复制的版本存储技术,并给出了一个改进的版本存储模型。     

基于基线的软件配置管理版本控制

版本控制是软件配置管理的重要功能,负责为配置库中的所有元素自动分配版本标识,并保证版本命名的惟一性。文中运用软件工程的原理并结合版本控制的实践,首先指出为了有效地进行版本控制而引入基线管理,并通过图形表示最常用的软件项目基线;然后研究版本管理,包括版本管理的功能、版本树、版本的串行与并行演变过程,并通过图形给出了版本演变历史和组件版本的变化过程;最后研究版本控制的主要内容,包括检入检出控制、分支和合并、历史记录。结果表明,在配置管理过程中通过基线进行版本控制,是保护代码资源、提高开发效率、加强软件项目管理的有效途径。     

CoEditor:一个支持群体协同写作的编辑系统

协同编辑器CoEditor是一个以人为中心,支持时空分布的人们通过协作共同完成电子文档的编辑、讨论及修改完稿的全过程.在详细论述CoEditor的系统结构及功能特点的基础上,就基于EDBMS的五层文档库结构设计、以人为中心的协同感知、加锁粒度可变的并发控制、基于版本差的版本管理技术问题进行了讨论.     

基于CSCW的多媒体远程协同编辑系统的设计与实现

计算机支持的协同工作(Computer-SupportedCooperativeWork,缩写为CSCW)主要研究如何利用计算机技术和网络通信技术支持工作组成员在共享环境下的分工合作、协同工作以及交互协商。文章主要讨论在CSCW的环境下,协同编辑系统如何实现多媒体对象的协同编辑及其版本控制。     

云同步系统中采用增量存储的版本控制技术研究

用户在使用云同步系统时,常常需要对文件执行版本恢复等操作.涉及到文件的版本问题,需要在云同步系统中引入版本控制功能对用户文件进行版本管理,这将不可避免地给系统带来版本冲突、版本存储冗余等诸多问题,这些问题可以通过建立一个良好的版本模型,制定完善的策略予以解决.首先对云同步系统以及其版本特点进行了分析和描述,并根据这些特点对版本以及版本存储进行建模,提出了增量存储以及版本恢复的具体实现,并通过对与全量存储方式以及现有增量存储方式的对比实验进行分析,论证了方案的合理性、可用性以及优越性.     

协同图形编辑系统中改进的多版本技术

基于版本复制的多版本技术采用全复制的系统结构实现协同图形编辑系统中冲突操作的意愿保证问题.每个版本存储了编辑过程中所有在此版本上执行过的操作,故存在同一操作被存储多次和操作存储量随编辑过程的继续出现大规模增加的情况.本文从冲突操作集合着手,提出了一种改进的多版本技术,通过理论证明和模拟实验结果表明这种改进的多版本技术能有效地克服以上问题.     

基于C/S的协同任务管理系统的设计与实现

在传统的协同任务管理控制系统基础上扩展了基于任务的需求分解和任务过程的版本控制功能,以达到监控任务的开发过程,并记录任务的版本升级信息的目的.提出了基于C/S协同任务管理的系统架构,采用VS.net为应用程序开发工具、结合SQL Server为数据库后台,完成了该系统的设计和实现,着重阐述了协同任务管理的新特征和扩展模块(任务监控、版本控制)的技术实现过程与方法.     

面向中小机构的文件管理系统的设计与实现

针对目前中小机构对文件管理的需求,分析当前网盘存在的问题,设计研发一款操作便捷、管理有效的轻量级文件管理系统。该系统采用标签技术对文件进行分类和检索,通过虚拟文件层和SHA-1算法实现了文件去重和资源回收,利用分布式的版本控制思想有效地解决了多用户情况下文件版本控制问题,保证了用户访问数据的一致性,实现了网络文件存储、文档协同修改、多用户共享文件等功能。实际应用情况表明,系统能够有效地管理和共享文件,实现多用户协同工作,对重复文件能够自动检测和删除,大大提高了存储资源和网络资源的利用率,降低了资源管理复杂度。     

多版本技术中相同操作的处理策略

意愿保证是协同编辑系统中的关键问题之一,其研究具有挑战性.多版本技术通过对象复制策略有效地解决实时协同图形编辑系统中的冲突操作的意愿保证问题.本文分析了编辑中一类重要操作--相同操作在多版本技术及其对象标识中存在的问题,提出了一个对象版本标识解决方案和相关的策略,并讨论了相同操作对操作历史日志的维护的影响和改进.实验表明,本文提出的方法有效地完善了多版本技术中对不同操作的处理.     

Integrating XML and CORBA to support collaborative writing using off-the-shelf editing software

In this paper, collaborative writing is modeled as a workflow application comprising a number of activities. Each activity is assigned to a co-author to edit certain part(s) of the shared document. The order of editing is governed by a workflow schedule, which can be modified during execution. To enable concurrent editing, a data definition scheme is proposed whereby documents are transformed into the XML format for internal storage. Effectively, a hierarchical structure is superimposed on each document, allowing it to be broken down into a number of independent parts. These parts may then be separately edited in parallel. Unlike other approaches, the system supports the use of off-the-shelf editor software. Users can thus adapt to the system easily and existing documents can also be re-used rapidly. A prototype has been built which supports collaborative editing of Microsoft Word^TM${}^{\mathrm{TM}}$ documents.     

基于锁定机制的电网GIS多用户协同编辑研究

针对电网GIS中多用户协同编辑的现实需要,在确保编辑数据一致性和正确性的基础上,结合任务划分和版本管理技术,提出了基于锁定机制的电网GIS多用户协同编辑.首先分析了协同编辑的体系结构和编辑流程,然后描述了协同编辑中锁定机制的实现算法、锁定流程以及客户端之间数据同步,最后结合实际项目需求构建原型系统,对基于锁定机制的电网GIS多用户协同编辑进行了验证.     

Design issues and model for a distributed multi-user editor

The collaborative editing of documents is a very common task nowadays. Writing groups are often distributed over many locations because of the globalization of organizations and the increasing interdisciplinarity of tasks. Since many writers already use computers for their jobs, providing computer support for the collaborative writing process has been identified as an important goal. Numerous tools for computer supported collaborative writing have already emerged but in most cases have not come into widespread usage. In this article the requirements of users for a collaborative editor are analyzed. Providing as much flexibility as possible to the users is identified as a basic need. According to the requirements summary a model for a group editing environment is presented. The model covers cooperative work in local and wide area networks using synchronous and asynchronous cooperation. Finally, an application of the model is presented in the form of the multi-user editing environmentIris.     

Optional and responsive fine-grain locking in Internet-based collaborative systems

Locking is a standard technique used in distributed computing and database systems to ensure data integrity by prohibiting concurrent conflicting updates on shared data objects. Internet-based collaborative systems are a special class of distributed applications which support human-to-human interaction and collaboration over the Internet. In this paper, a novel optional and responsive fine-grain locking scheme is proposed for consistency maintenance in Internet-based collaborative editors. In the proposed scheme, locking is made optional in the sense that a user may update any part of the document without necessarily requesting a lock. In the face of high communication latency in the Internet environment, responsive locking is achieved by granting the permit to the user for updating the data region immediately after issuing a locking request. Moreover, multiple fine-grain locks can be placed on different regions inside a document to allow concurrent and mutually exclusive editing on the same document. Protocols and algorithms for locking conflict resolution and consistency maintenance are devised to address special technical issues involved in optional and responsive fine-grain locking. The proposed locking scheme and supporting techniques were implemented in an Internet-based collaborative editor to demonstrate its feasibility and usability.     

A Multi-Versioning Scheme for Intention Preservation in Collaborative Editing Systems*

Although the multi-version approach to consistency maintenance has been widely discussed and implemented in database systems, version control systems, and asynchronous groupware systems, its potential in real-time groupware systems is largely unexplored. Intention preservation is an important aspect of consistency maintenance in real-time collaborative editing systems, where multiple users cooperate with each other by concurrently editing the same document. The multi-version approach is supposed to be able to preserve individual users’ concurrent conflicting intentions. In this article, we propose a new multi-versioning scheme that can preserve not only concurrent conflicting intentions but also contextual intentions while achieving convergence of the document under editing. By extending an existing multi-versioning scheme to a general one that specifies the conditions for convergence, we decouple the discussion of convergence from that of intention preservation. By constraining the general scheme, we arrive at the novel scheme that guarantees to preserve users’ intentions. The correctness of the scheme has been formally verified. The design of an algorithm for consistent version composition and identification has been discussed in detail.     

The design and implementation of an interactive document editor

General-purpose text editors have significant drawbacks when used for document preparation. This paper describes a system designed to combine the editing and formatting power of a text editor with the simplicity and immediacy of a typewriter for document preparation. The system is implemented on a minicomputer with a simple alphanumeric visual display unit.     

An efficient and secure approach for a cloud collaborative editing

The demand for cloud-based collaborative editing service is rising along with the tremendously increased popularity in cloud computing. In the cloud-based collaborative editing environment, the data are stored in the cloud and able to be accessed from everywhere through every compatible device with the Internet. The information is shared with every accredited user in a group. In other words, multiple authorized users of the group are able to work on the same document and edit the document collaboratively and synchronously online. Meanwhile, during the whole collaborative editing process, the encryption technique is eventually applied to protect and secure the data. The encryption for the collaborative editing, however, could require much time to operate. To elevate the efficiency of the encryption, this study first analyzes the text editing in the collaborative service and presents a framework of the Red–Black tree, named as rbTree-Doc. The rbTree-Doc can reduce the amount of data to be encrypted. Although the trade-off for creating the Red–Black tree introduces extra cost, the experimental results of using rbTree-Doc in text editing operations, such as insertion and removal, show improved efficiency compared with other whole-document encryption strategy. Using rbTree-Doc, the efficiency is improved by 31.04% compared to that 3DES encryption is applied and by 23.94% compared to that AES encryption is applied.