基于CSCW的CAD系统协作支持技术与支持工具的研究

计算机支持的协同工作（CSCW）给CAD技术带来重大发展，但仍然存在许多问题。其中之一是缺乏将协作性能同应用功能有机结合的方法。文中在分析的现有协作支持技术，工具和系统不足的基础上，提出了用协作支持工具软件CoCADToolAgent改造商品化CAD系统来开发CSCD系统的新思路和总体技术路线，给出了通讯支持，协议，一致性维护和并发控制，协同感知，任务和脚色机制的有效的实现方法，作为本方法的一个应用实例，成功地将传统的人机交互式CAD系统AutoCAD转变为网络环境下支持人人交互的CSCD原型系统，作为专用协作支持工具，CoCADToolAgent比NetMeeting之类的通用协作支持工具具有更好的协作性能，该方法可推广到三维CAD系统。     

Using Distributable User Interfaces in CSCL In-Situ Classrooms

Distributable user interfaces enable users to distribute user interface interaction objects (i.e. panels, buttons, input fields, checkboxes, etc.) across different displays using a set of distribution primitives to manipulate them in real time. This work presents how this kind of user interfaces facilitates the computer supported collaborative learning in modern classrooms. These classrooms provide teachers and students with display ecosystems consisting of stationary displays, such as smart projectors and smart TVs as well as mobile displays owned by teachers and students, such as smartphones, tablets, and laptops. The distribution of user interface interaction objects enables teachers to modify the user interface interaction objects that are available to students in real time to control and promote the collaboration and participation among them during learning activities. We propose the development of this type of applications using an extension of the CAMELEON reference framework that supports the definition of UI distribution models. The Essay exercise is presented as a case of study where teachers control the collaboration among students by distributing user interface interaction objects.     

A web-based computer-aided pneumatic circuit design software

A web-based collaborative pneumatic software is created to assist users on the computer-aided pneumatic circuit design. The software is developed in the form of Java application and Java applet. Therefore, it can be used in any computer with Java virtual machine or be accessed by a web browser over the internet.This software allows user to conduct pneumatic circuit design by (1) applying the circuit components on menu bar to draw the pneumatic devices, (2) connecting the devices with signal lines, (3) filling in the parameters for all the devices and finally, (4) simulating the designed circuit. To provide better simulation results for each device, separate threads are used to perform continuous scans to each component. Therefore, the actions of the pneumatic devices and circuits can be simulated throughout the design phases. The circuit design results can be saved either on each local disk for Java application users or on web-based databases for collaborative users.During a collaborative mode, the user who owns the token will dominate the circuit design process while the other users can only monitor the consequences. The token can be passed around the users on a collaborative scheme.Since the software is designed in Java, all pneumatic devices were designed as component based objects to allow user defined devices to be incorporated into the software in a systematic way.     

关于AUTO CAD在图形图像教学领域的多元结合应用

AUTO CAD是一款交互式计算机辅助设计以及绘图的软件,在传统的教学中很多学生都认为这款软件的学习十分困难,所以很难提起学习兴趣,还有一些学生学习了后面的知识就会忘记前面的知识,这就使得教学质量与效率很难提升。为此,教师应积极主动探索有效的教学方式,激发学生的ATUO CAD软件的学习兴趣,提升教学和学习的质量。本文就探讨ATUO CAD在图形图像教学领域的多元结合应用。     

Creating cognitive tutors for collaborative learning: steps toward realization

Our long-term research goal is to provide cognitive tutoring of collaboration within a collaborative software environment. This is a challenging goal, as intelligent tutors have traditionally focused on cognitive skills, rather than on the skills necessary to collaborate successfully. In this paper, we describe progress we have made toward this goal. Our first step was to devise a process known as bootstrapping novice data (BND), in which student problem-solving actions are collected and used to begin the development of a tutor. Next, we implemented BND by integrating a collaborative software tool, Cool Modes, with software designed to develop cognitive tutors (i.e., the cognitive tutor authoring tools). Our initial implementation of BND provides a means to directly capture data as a foundation for a collaboration tutor but does not yet fully support tutoring. Our next step was to perform two exploratory studies in which dyads of students used our integrated BND software to collaborate in solving modeling tasks. The data collected from these studies led us to identify five dimensions of collaborative and problem-solving behavior that point to the need for abstraction of student actions to better recognize, analyze, and provide feedback on collaboration. We also interviewed a domain expert who provided evidence for the advantage of bootstrapping over manual creation of a collaboration tutor. We discuss plans to use these analyses to inform and extend our tools so that we can eventually reach our goal of tutoring collaboration.     

基于Agent的协同设计中的工作流管理系统

针对CAD协同设计的特点,结合状态图和Agent技术的优势,提出了基于Agent的状态图工作流管理模式,讨论了其关键技术和实现方式,并以建筑设计为例进行了验证,为协同设计中的工作流管理提供了有益的参考。     

Intra‐organizational user‐centred design practices: The impact of design research departments at design consultancies

The user is a critical factor in design and innovation. Firms experiment with different approaches to involving the user in design processes, which results in new forms of intra‐ and extra‐organizational collaboration. The establishment of in‐house design research units within design consultancies is one such intra‐organizational user‐centred design practice that targets designer‐researcher collaboration. This paper addresses this issue and reports on the findings from multiple case study research exploring the impact of in‐house design research teams on designers' user knowledge construction. We utilized constructivist learning theory to assess major aspects of these intra‐organizational user‐centred design practices. Ethnographically informed field studies were conducted at six design consultancies representing three design fields (i.e., architecture, industrial design and interaction design) in the Northwestern United States. Three of the consultancies have design research departments and three do not. The findings indicate that in‐house design research units play a role in designers' user knowledge construction via their results, processes and human resources. Among these, the active participation of designers in the research process was observed to have the largest impact because of its contribution to designers' contextual and collaborative learning about users.     

异构CAD系统协同框架与互操作

协同CAD通过网络支持不同地域的设计人员实时地完成产品设计或决策任务,以提高群体协同工作效率;异构CAD系统协同将分布的不同的CAD系统,如ProE、UG、SolidWork等业界比较成熟且是主流的商业CAD系统,集成在一个框架平台下,从而支持人们更方便地协同工作;文章讨论了异构CAD系统协同的体系结构与共享感知问题,提出了一个支持共享感知的复制式系统结构模型;进一步将现有商业CAD系统引入到该模型中,给出了一个基于构件的协同CAD中间件框架模型,讨论了中间件接口和CAD系统的互操作。     

The foundations of a theory-aware authoring tool for CSCL design

One of the most useful ways to enhance collaboration is to create scenarios where learners are able to interact more effectively. Nevertheless, the design of pedagogically sound and well-thought-out collaborative learning scenarios is a complex issue. This is due to the context of group learning where the synergy among learners’ interactions affects learning processes and, hence, the learning outcome. Although many advances have been made to support the designing of collaborative learning scenarios through technology, a more systematic approach is lacking. With the limitations of the current designing methods and tools, it is difficult to develop intelligent authoring systems that can guide users in order to produce more effective collaboration. One of the main difficulties with creating a more consistent (computer-understandable) approach to designing collaboration is the necessity of proposing better ways to formalize the group learning processes. In this paper, we present an innovative approach that uses ontologies and concepts from learning theories to create a framework that represents collaborative learning and its processes. Ontologies provide the necessary formalization to represent collaboration, while learning theories provide the concepts to justify and support the development of effective learning scenarios. Such an approach contributes to establish the foundations for the development of the next generation of intelligent authoring systems referred to as theory-aware systems. To verify the viability and usefulness of our proposed ontological framework in the context of systematic design, the development and use of an intelligent authoring tool for CSCL design is presented. This system is able to reason on ontologies to give suggestions that help users to create theory-compliant collaborative learning scenarios. We carried out several experiments with teachers in a geometry drawing course and the results indicate that the system helps teachers to create and interchange their scenarios more easily and facilitates the selection of important pedagogical strategies that influence positively the designing and effectiveness of group activities.     

An evolutionary approach to prototyping pedagogical agents: from simulation to integrated system

We have developed and integrated software agents with two educational groupware systems (TeamWave Workplace and FLE), using evolutionary prototyping and empirical-based design as development techniques. The resulting prototypes of pedagogical agents (CoPAS, SA-Agent and RuleEditor) provide learners and teachers with increasingly domain-specific support for distributed collaborative learning activities. Employing the evolutionary approach has enabled us to build and evaluate early prototypes of complex systems with cost-effective techniques and involving users in this process helped us to constrain the design space and direct further development. CoPAS is a simulation experiment carried out with the Wizard of Oz technique, SA-Agent is a pedagogical agent integrated with an open-source learning environment, and RuleEditor is a customizer for the SA-Agent. The agents collect statistical information on user activity and analyze that information based on principles of collaboration and knowledge building. The results are presented as advice in the user interface of the learning environments to promote students' reflection on their collaboration and knowledge-building activities. If instructors disagree about the phrasing of the advice or the frequency of intervention, they can change it using the RuleEditor agent customizer.     

分布式同步协同包装纸盒CAD/CAM系统的设计与实现

采用Java技术开发了基于Web的分布式同步协同包装纸盒CAD／CAM系统．研究了纸盒CAD／CAM系统的体系结构、系统功能的分配、分布式同步协同设计、并发控制、协同感知、负载均衡、3D可视化技术、参数化设计以及系统安全性的保证等关键技术．     

Development of a collaborative CAD/CAM system

This paper presents the development of a collaborative CAD/CAM system (COCADCAM). COCADCAM extends an existing single-location CAD/CAM system to a multi-location CAD/CAM application so that two geographically dispersed CAD/CAM users can work together on a three-dimensional CAD-geometry coediting and CAD-related tasks collaboratively and dynamically. COCADCAM dynamically supports CAD data communication that are not available in traditional single-location CAD/CAM. The dynamic data communication is achieved through the development of networking algorithms and CAD/CAM functions in this paper. The networking algorithms based on UNIX Interprocess Communication (IPC), the Network File System (NFS), and a connection-oriented client and server model under the Transmission Control Protocol/Internet Protocol (TCP/IP) suite. The CAD/CAM functions included surface modelling, simulation of a milling toolpath, and post-processing of an NC program following collaborative CAD-geometry coediting, which are directly or indirectly supported by the Application Programming Interface (API) of the CAD/CAM software. The networking algorithms and CAD/CAM functions together can facilitate an environment for CAD-geometry coediting and related tasks such as design, analysis and manufacture. COCADCAM has been successfully implemented through local area network (LAN) and the Internet; a remote machining cell is also linked so that the generated NC program based on a coedited free-form surface can be used for the physical machining operation. The algorithm proposed by COCADCAM can be referenced for the extension of other single-location CAD/CAM systems to multi-location applications.     

Component-based tailorability: Enabling highly flexible software applications

Component technologies are perceived as an important means to keep software architectures flexible. Flexibility offered by component technologies typically addresses software developers at design time. However, the design of software which should support social systems, such as work groups or communities, also demands ‘use-time’, or technically spoken, ‘run-time’ flexibility. In this paper, we summarize a decade of research efforts on component-based approaches to flexibilize groupware applications at run-time. We address the user as a ‘casual programmer’ who develops and individualizes software for his work context. To deal with the challenges of run-time flexibility, we developed a design approach which covers three levels: software architecture, user interface, and collaboration support. With regard to the software architecture, a component model, called FlexiBeans, has been developed. The FreEvolve platform serves as an environment in which component-based applications can be tailored at run-time. Additionally, we have developed three different types of graphical user interfaces, enabling users to tailor their applications by recomposing components. To enable collaborative tailoring activities, we have integrated functions that allow sharing component structures among users. We also present different types of support techniques which are integrated into the user interface in order to enable users’ individual and collaborative tailoring activities. We conclude by elaborating on the notion of ‘software infrastructure’ which offers a holistic approach to support design activities of professional and non-professional programmers.     

From dialogue to monologue and back: Middle spaces in computer-mediated learning

The authors develop a framework for the design of tools to mediate collaboration intended to lead to learning. We identify two categories of media that are common in computer-supported collaborative learning and software in general: communication media and information media. These two types of media are then mapped onto two types of social activities in which learning is grounded: dialogue and monologue. Drawing on literature in learning theory, we suggest the need for interfaces that help students to transition from dialogue to monologue and back again. We examine in detail two cases of students participating in a computer-mediated science learning activity that involved technologies designed to support this transition, and suggest ways that the “middle space” can be supported with software and activities that transcend some of the traditional tradeoffs associated with information and communication interfaces.     

Evaluating the value of collaboration systems in collocated teams: A longitudinal analysis

Distributed work structure has increased the importance of group work. Consequently, the usage of collaboration systems that support group work has increased exponentially. However, limited research exists on why collocated group members use collaborative system and how their perceptions about the system change from project initiation to project completion. The study proposes resource management support, coordination support, and evaluation support as key aspects based on which collocated users form beliefs about collaboration system value. Based on technology acceptance model and expectancy disconfirmation theory, we propose a model that examines the evolution of user beliefs from pre to post-adoption stage. Further, we argue that users may engage in different information processing strategies as part of the belief change process. The research model was examined based on longitudinal data collected from student groups working on a software application development project over a three month period. The results show that users deemed all features to be valuable at the pre-adoption stage. However, at the post-adoption stage evaluation support was the only factor that had a direct influence on collaboration system usefulness. While the impact of other support factors was mediated through the confirmation process. Further, users engaged in high information processing in revising their beliefs about collaboration system features, when they experienced a high level of dissonance. On the contrary, a dual information processing approach was visible in the context of support features that required adjustment or update to beliefs from pre to post-adoption stage. The study provides three core areas around which designers can structure collaboration system features to make it more useful. It also provides theoretical insights into the process through which user cognitions about collaboration system value change over time.     

An investigation of coopetitive pedagogic design for knowledge creation in Web-based learning

Information and communication technologies (ICTs) have created a supportive environment for collaborative learning at the expense of student motivation and engagement. This study attempts to explore the development of a productive learning atmosphere in the context of Web-based learning. An experiment is conducted with university-level students having homogenous background and coursework by applying heterogeneous pedagogies that create either competitive or collaborative learning atmospheres. The differences in learning atmosphere bring about variations in social presence and enjoyment of learning. The findings show that “coopetition” (defined as collaboration within the group and competition between groups) was the best learning strategy because competition and collaboration stimulated different types of knowledge growth in the knowledge-creation spiral. Competitive learning atmospheres encourage students to develop higher analytic skills, while collaborative learning atmospheres prompt students to demonstrate higher synthetic skills. Because both atmospheres contribute to learning, this study has found that combining both pedagogies in constructing a coopetitive learning atmosphere not only contributes to analytic and synthetic skills, but also raises the overall knowledge level. The findings pinpointed the importance of creating a learning environment that integrates ICTs, learners’ backgrounds, courseware, and pedagogic considerations in the process of increasing knowledge levels.     

Collaborative user modeling for enhanced content filtering in recommender systems

Recommender systems, which have emerged in response to the problem of information overload, provide users with recommendations of content suited to their needs. To provide proper recommendations to users, personalized recommender systems require accurate user models of characteristics, preferences and needs. In this study, we propose a collaborative approach to user modeling for enhancing personalized recommendations to users. Our approach first discovers useful and meaningful user patterns, and then enriches the personal model with collaboration from other similar users. In order to evaluate the performance of our approach, we compare experimental results with those of a probabilistic learning model, a user model based on collaborative filtering approaches, and a vector space model. We present experimental results that show how our model performs better than existing alternatives.     

情境教学法及项目学习在建筑CAD教学中的应用

近年来,CAD制图软件已经成为国内外最为广泛应用的制图软件,其改变了过去手工制图的弊端,实现了计算机智能化制图功能,并且有效提高了设计精确性和总体工作效率。目前,许多高等院校尤其是建筑类高等院校已把建筑CAD课程作为重点教学课程来抓。建筑CAD课程教学过程中,应用情境教学法及项目学习能够实现任务驱动的学习,有效提高学生的学习积极性,培养学生的实践能力和解决实际问题能力,达到理想的教学效果。该文就情境教学法及项目学习在建筑CAD教学中的应用进行了探讨研究。     

以网络为中心的协同特征造型

在网络化同步协同设计环境中,如何实现CAD系统之间的实时数据交换和模型同步,成为协同几何造型的关键问题。文中提出了一种新的复制式协同特征造型方法,该方法将现有的特征造型技术与分布计算、网络通信技术相结合,通过简单的造型消息交换来实现增量式协同造型,可以较好地满足几何模型实时同步的需要,而且也部分地解决了异构CAD软件之间的数据交换问题;并详细地介绍了协同造型通信协议、对象引用机制、以及分布式协同造型系统。     

Separating the effects of knowledge construction and group collaboration in learning outcomes of web-based courses

This research investigates the effects of knowledge construction and group collaboration in outcomes of MBA courses entirely delivered on the web. The data comes from a sample of courses conducted from summer 2000 through summer 2002. The results indicate that students achieve higher perceptions of learning in courses where knowledge is transmitted through the system, as opposed to constructed by the students, and when students are engaged in collaborative assignments. In terms of final grades, our findings show that the absence of both factors (knowledge construction and group collaboration) has a detrimental effect on student performance. Students earn on average better grades in courses where either one of these factors is present. Contrary to our expectations, the presence of both factors does not have positive synergistic effects on student performance. These findings suggest that the success of web-based courses entirely delivered online depends upon providing collaborative learning activities, and/or challenging environments where the students are responsible for the creation of their own knowledge.