基于文档标注的并发控制方法

在不可忽略的网络延迟的情况下，由于CSCW系统的高响应度的要求，系统需要使用完全复制分布式结构，这是对并发控制的严峻挑战，从而也产生了新的问题，如违背操作意愿，基于文档标注的并发控制方法，引入状态向量，不仅符合整体一致性模型，而且易于理解，并且效率较高。     

协同编辑系统中保持共享对象一致性的研究

如何保持共享对象的一致性是实时协同设计中的核心问题.文中介绍了一种新颖的保持共享对象一致性的方法.根据协同图形编辑系统中操作冲突的特点,使用消息驱动机制,配合同步机制和冲突检测与消解机制,使得系统既能保持共享对象的一致性,又满足了实时协同设计中的响应性、因果顺序一致性,并最大限度地保持了用户的操作目的.     

协同编辑系统中保持共享对象一致性的研究

如何保持共享对象的一致性是实时协同设计中的核心问题。文中介绍了一种新颖的保持共享对象一致性的方法。根据协同图形编辑系统中操作冲突的特点,使用消息驱动机制,配合同步机制和冲突检测与消解机制,使得系统既能保持共享对象的一致性,又满足了实时协同设计中的响应性、因果顺序一致性,并最大限度地保持了用户的操作目的。     

同步协同设计中并发控制的研究

为解决协同设计过程中存在的数据一致性不高、数据传输量大、实时性差等问题,通过分析分布式CSCW环境中并发控制的各种方法,并根据同步协同设计特点和用户操作意愿,设计了并发控制网络模型.在该模型中,计算数据传输的最小延时确定主控站点,提出了基于事务优先权的混合并发控制策略,以保证协同用户在操作过程中的并发率.实例证明,以上措施的实现保证用户自由共享资源,提高了并发控制的实时性和数据的一致性.     

集中式CSCW环境中对实时共享对象的并发控制算法

在实时CSCW环境中，必然存在多个用户都需要同时访问的共享对象，系统必须对用户访问对象的操作做出实时的响应，以使对象的变化与用户的期望相一致，本文提出了一种解决并发控制的方法，目标是在并发和实时的情况下实现多客户感知的对象一致性，算法基于变换和用户期望，利用前向变换来构建对象的历史记录。     

协同图形编辑系统中一种改进的多版本递增创建算法

并发控制技术是CSCW研究的关键技术之一，旨在对并发操作进行控制以达到一致性维护的目的。本文对协同图形编辑系统中一种新颖的多版本方法进行了研究，提出了一种改进的多版本对象动态递增创建算法，并通过模拟实验结果表明：改进后的算法性能有较大的提高。     

基于图形对象的一致性维护问题的研究

针对实时协同图形编辑系统中一致性维护关键问题,提出了一种基于图形对象的并发控制算法。该算法扩展了面向文本编辑的分布式操作转换dOPT算法,满足图形对象属性级上数据一致性维护,同时通过预定义图形对象间的关联关系和位置属性约束规则,进行操作语义维护管理,使得实时协同图形编辑系统的一致性维护更为有效和完备。     

考虑工程图形协同应用特点的并发控制研究

并发控制是CSCW系统的关键技术，没有统一标准，通常要根据协同应用的特点来构造。文中以CAD系统内部数据库拓扑结构的一致性作为显示一致性的基础，适时放宽整体一致性模型中的事件定义条件和一致性判定条件，提出一种改进的整体一致性模型。按照该模型的事件关系定义，通过图形对象全局ID标识的一致性维护和添加操作的相关性分析，提出一种添加操作优先的并发控制策略。基于上述模型和策略，研究了一种偏复制式混合体系结构下的悲观和有限乐观的并发控制方法，以及相应的并发控制协议实施技术。工程实践证明，这些并发控制模型、策略、方法和技术充分考虑了工程图形数据结构及其协同应用特点，从而有效地支持设计过程中的人人交互。     

基于协同式移动Agent的分布式数据库系统研究

CSCW通过先进的通信技术和多媒体技术建立一个支持协同工作的平台，移动Agent在网络中执行事务和信息提取工作上提供了新的方法。将CSCW和Agent的概念引入到分布式数据库中，建立一个具有群体性、交互性、协作性的分布式人机网络工作环境COMAM，通过这个网络环境的支持，不同用户对地理上分布的各种类型的数据库可以进行协同性数据库操作。     

本地滞后方法中的多级滞后时间计算

本地滞后方法是缓解分布式虚拟环境一致性问题的重要技术。现有的本地滞后技术在一个时间段内为所有操作设置统一的滞后时间,没有考虑到不同操作背景对操作的不同一致性需求。本文提出本地滞后方法中的多级滞后时间计算,根据被操作实体与其它实体距离的远近将操作分为不同一致性等级,分别计算滞后时间。该方法可以对系统反应速度与一致性进行更灵活的折衷,提高了分布式虚拟环境的性能,并在实际应用中取得了良好效果。     

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.     

具有实时反馈的草图交互识别方法

针对同步在线草图识别算法中的效率和应用范围问题,提出基于增量式意图提取的识别算法．算法通过定义滞后窗口,采用增量式意图提取的方式理解用户的勾画意图,进而根据当前信息修正以前生成的意图段落,使得识别结果和用户的勾画意图保持一致．实验证明,该算法能够准确、实时地识别用户输入的多种图形．     

基于意图认知的复杂电气产品外观设计策略

受功能结构等多重约束和功能导向设计理念影响,复杂电气产品外观设计更关注 工程技术的合理性和功能表达的完整性,易忽略用户对产品的认知体验需求。针对这一问题, 分析该类产品外观设计意图产生模式和用户意图认知模式,总结意图认知中存在的 3 个问题： 用户认知创新与失真导致意图超出与缺漏、设计师与用户的认知差异导致语义鸿沟、用户单纯 化认知导致理解障碍。针对性提出复杂电气产品的 3 项外观设计策略：基于质量功能配置法 (QFD)的用户认知前置、构建延续性与差异性并存的外观设计特征库、以用户认知和工程约束 共性特征为引导的族群收敛,以在技术约束基础上实现用户对设计意图信息的获取和情感的满 足,进而提升该类产品外观设计的市场竞争力。     

实时图案协同设计中冲突问题的研究

在Internet环境中,允许多个用户同时对同一图案的任意绘图区进行设计是图案协同设计系统应满足的基本要求．然而不同设计者在协同设计过程中由于设计意图的不同而引起的操作冲突是不可避免的,因此冲突问题是图案协同设计系统的关键问题之一．着重讨论了冲突的定义,冲突的多种避免方式,提出了高效的冲突检测算法和一种能保护用户协同设计意图的冲突解决方法——基于冲突操作锁定的冲突解决方法．这些方法和算法的实现使得在分布式计算环境下协同设计的冲突问题得到了较完善的解决．     

e-Learning continuance intention: Moderating effects of user e-learning experience

This study explores the determinants of the e-learning continuance intention of users with different levels of e-learning experience and examines the moderating effects of e-learning experience on the relationships among the determinants. The research hypotheses are empirically validated using the responses received from a survey of 256 users. The results reveal that negative critical incidents and attitude are the main determinants of the users’ intention to continue using the e-learning, irrespective of their level of e-learning experience. In addition, the findings show that the user’s experience of the e-learning service plays a moderating role. The impact of negative critical incidents on perceived ease of use is greater for less experienced users. By contrast, the impact of negative critical incidents on perceived usefulness is greater for more experienced users. Perceived ease of use has a more critical effect on the attitude and continuance intention of less experienced users, whereas perceived usefulness is found to be a stronger determinant of the attitude and behavioral intention of more experienced users. Moreover, the relationship between satisfaction and continuance intention is stronger for less experienced users than for more experienced users. The implications of the present findings for research and managerial practice are analyzed and discussed.     

基于概率推理的入侵意图识别研究

攻击者的入侵行为背后往往蕴含着攻击者的目标和意图,据此提出了入侵意图识别的层次化模型。为了处理网络环境中的不确定性信息,提出了基于概率推理的入侵意图识别算法,并在此基础上预测攻击者的后续攻击规划和目标,从而起到提前预警的作用。根据网络安全事件、目标和意图之间的因果关系建立的贝叶斯网络能够描述和处理并发意图识别问题。试验证明了该方法的可行性和有效性。     

基于复制结构的协同绘图并发控制算法

协同绘图是计算机支持的协同工作(CSCW)的重要研究方向,复制模式下的实时协同图形编辑系统支持不同地域的设计人员通过网络同步高效地浏览、操作和修改各种图形,其中操作意愿保证及其并发控制成为复杂而又关键的问题之一.讨论了基于复制结构的并发控制策略,给出了一个有效的适合图形对象并发控制算法.     

Modeling and Mining of Users' Capture Intention for Home Videos

With the rapid adoption of consumer digital video recorders and an increase of home video data, content analysis has become an interesting and key research issue to provide personalized experiences and services for both camcorder users and viewers. In this paper, we present a novel view to tackle this issue, which aims at modeling and mining of the capture intention of camcorder users. Based on the study of intention mechanism in psychology, a set of domain-specific capture intention concepts is defined. A comprehensive and extensible scheme consisting of video structure decomposition, intention-oriented feature analysis, as well as singular-value-decomposition-based intention segmentation and learning-based intention classification is proposed to mine the users' capture intention. Experiments were carried on home video sequences of 90 h in total, taken by 16 persons over the past 20 years. Both the user study and objective evaluations indicate that our proposed intention-based approach is an effective complement to existing home video content analysis schemes     

Exploring sustained participation in firm-hosted communities in China: the effects of social capital and active degree

Firm-hosted online communities are user-centred, and their efficacy depends on the users’ sustained participation. This study investigated the impact of social capital on users’ continued usage intention. Specifically, since very little work has been done to explore the antecedents of social capital, we tested the role of operator-related and individual-related factors in cultivating social capital by proposing an integrated research model to fill this gap. Furthermore, to gain deeper insights into continuance intention, we postulate that active degree moderates the relationship between social capital and users’ continued usage intention. Our model is empirically examined using survey data collected from 373 members of a well-known firm-hosted online community in China. The results reveal that the firm’s reaction, offline activities, interaction support, seeking reputation and perceived enjoyment are the significant antecedents of social capital. Additionally, social tie and shared vision exert a stronger effect on continued usage intention for active users, whereas identification has a higher influence on continued usage intention for inactive users. Finally, this study discusses the theoretical and practical implications of these findings and provides possible directions for future research.     

How to unite the power of the masses? Exploring collective stickiness intention in social network sites from the perspective of knowledge sharing

This study aims to investigate users’ knowledge-sharing intention and collective stickiness intention towards social network sites (SNS). SNS offer an opportunity for users to interact and form relationships, while knowledge is accrued by integrating users’ information, experience, and practice. However, there have been few systematic studies that question why people use SNS to share knowledge. We adopt social capital theory, social identity theory, as well as use and gratification theory, to explore the determinants of members’ knowledge-sharing intention in using SNS. The survey was conducted on two education virtual communities (VCs) on Facebook, of which most members were teachers and educators. Data analysis was executed to validate our research model, and SmartPLS was used to analyse users’ collective stickiness intention. The results show that social capital and social identity have an impact on teachers’ knowledge-sharing intention, which, in turn, influences collective stickiness intention towards SNS. Our findings can not only help researchers interpret why members share their knowledge in VCs, but can assist practitioners in developing better SNS strategies as well.