以网络为中心的语义特征造型协同设计

在网络化同步协同设计环境中，如何实现用户系统之间的实时数据交换、维护特征语义的一致性，成为语义特征造型协同设计的关键问题。该文介绍了基于细胞元表示的语义特征模型，根据该造型技术的分层体系结构，基于对协同环境下特征操作的分析，采取了传输造型操作命令的策略，为解决特征语义一致性问题，提出了一种用操作特征管理器调度操作执行的方法，并给出了一个实例。     

基于增量模型的协同CAD建模关键技术研究

为了解决产品同步协同造型过程中由于模型信息庞大而造成设计修改无法及时反馈到客户端的问题,提出传输造型变化增量的方法.该方法避免修改后传输所有的模型信息,只需传输被设计修改影响部分的模型信息.提出了几何模型增量搜索算法,利用该算法搜索出协同CAD模型在修改前后发生变化的特征、拓扑关系和几何元素.将搜索结果封装成增量模型传输到客户端.设计出增量模型聚合算法,利用该算法将增量模型聚合到客户端原有几何模型上形成修改后的协同CAD模型.最后利用渐进式显示技术使协同造型设计者能更快地看到修改结果.     

基于特征的CAD数据交换方法研究*

分析了现有产品数据交换方法的基本特点并指出其不足之处,提出了一种基于特征的CAD数据交换方法,这种以定义造型功能映射集合为基础的新方法实现了不同CAD系统之间高效的数据交换,可保存高层设计意图。在Inventor和SolidWorks上初步实现了拉伸、旋转、扫描、圆角等几种特征数据交换,验证了方法的可行性。     

以网络为中心的几何造型技术

首先介绍了以网络为中心的CAD技术研究主题;然后围绕几何数据和设计工具的互操作性,从面向网络的模型数据表示、协同数据交换、基于网络的模型数据传输、多分辨率几何造型和网络化造型服务5个方面的关键技术,综述了以网络为中心的几何造型技术的研究进展;最后讨论了该领域存在的研究问题及其今后的研究方向。     

异构CAD系统集成技术综述

异构CAD系统集成是实现协同产品开发的重要环节.首先讨论基于几何数据交换的异构CAD系统集成方法,论述几何数据交换方法本身存在的问题、几何数据交换相比其他方法的不足;然后从参数化特征信息交换的核心问题、代表性研究工作和特征信息交换工具3个方面入手,分析基于参数化特征信息交换的异构CAD系统离线集成,并对基于操作命令交换的CAD系统在线集成工作进行介绍.最后对该领域未来的发展趋势进行了总结.     

异构CAD系统间中性语义特征数据交换

提出了一种基于中性语义特征转换的异构CAD系统间数据交换方法,该方法采用“中性语义特征转换器”将不同系统间的造型信息转换为统一的数据信息格式,并通过中性语义转换库实现了不同系统间操作命令的4种映射关系。此外,还实现了异构CAD系统间零件的同步协同传输。最后,将该文提到的思想初步应用在理工大学自主开发的HUSTCAIDS与UG间的异构协同设计中,证明该理论的可行性。     

基于Internet的协同CAD技术研究

协同CAD是将计算机网络、CSCW与CAD/CAM相结合的研究领域 ,协同CAD设计工具能够为分布式产品开发小组提供在线的、实时的协同讨论和问题求解的环境。通过对协同CAD的分析 ,提出协同CAD系统应划分为通用CSCW功能和专用CAD功能 ,并针对Internet低速网络环境下的实时性问题 ,详细地讨论了基于消息通信的显示同步和造型同步的实现技术。     

异构CAD系统语义信息交换方法研究

传输完整的CAD模型语义信息是协同设计有效进行的关键,提出了一种异构CAD系统语义信息交换方法,该方法通过构建语义转换器实现了常规文件、压缩文件和中性文件三种模型文件的数据转换和翻译,并给出了判定特征相似性的方法,实现了源CAD系统和目标CAD系统的语义互操作,保证了语义传输的完整性和高效性。构建了一个协同资源共享平台,在该平台下实现了Pro/E系统和UG系统之间的语义数据交换,协同传输效率提高了近30%。     

一种含设计意图的3D模型数据实时交换格式

为了在不同商用3D CAD系统之间实现含设计意图的几何模型数据的网上实时交换,提出了一种基于XML描述的数据交换格式,可将参考面的定位数据与局部坐标、组成轮廓草图的图元数据与约束关系、特征的构建形式与构建过程以层次结构化的方式包含在交换数据中,满足了同构与异构CAD系统之间实时交换含设计意图的数据之需要.     

从工业界的角度看CAD技术的研究主题与发展方向

回顾了现有CAD系统所采用的主流、成熟技术,包括特征造型技术,基于历史的造型、参数化设计以及组件技术．从工业界的角度分析了当前CAD技术的若干研究主题,包括CAD与互联网、曲面造型、数据交换、从二维到三维、概念设计与早期设计等．并展望了未来的CAD系统,包括未来的计算环境、未来的机械CAD、未来的数据共享以及未来的零件造型技术。     

分布式实时协同设计环境的研究

计算机支持的协同设计是适应分布式产品开发的设计方式。实时协同设计是协同设计的难点问题。文章提出了分布式实时协同设计环境的框架,研究了模型共享、协同设计agent、并发控制机制等关键技术,提出了基于Pro/E的实时协同设计环境的实现方法。     

协同语义特征造型系统的研究

针对目前大多数造型系统都是面向单用户环境开发,且造型过程依赖于特征的创建历程,提出以基于细胞元的语义特征造型系统为基础,采用B/S和C/S相结合的方式构造协同框架,进行协同造型的方法。介绍了系统的逻辑设计及网络实现方法。系统可为多用户提供在互联网上同时编辑同一个特征模型的协同设计环境,设计人员可根据特征依赖图（FDG）得到所需的视图,由于网络传输的是造型操作命令,而不是完整的图像信息,因此网络负荷较小,响应速度快。     

协同三维几何建模动态访问技术研究*

为解决协同设计过程中几何模型的动态访问问题,提出一种基于Web的协同设计环境下三维几何建模动态访问的分布式体系结构、异类CAD系统之间的动态数据交换组织模式。同时,提出一种面向对象的基于优先权限的乐观并发控制协议,保证模型动态访问在各站点操作的执行结果之间的一致性。在这些技术的共同作用下实现了协同三维几何建模动态访问技术,并通过具体实例验证了该技术的可行性。     

Semantic Web based innovative design knowledge modeling for collaborative design

This paper describes a study about how to use the Semantic Web technologies for innovative design knowledge modeling in a multi-agent distributed design environment. Semantic Web based knowledge modeling for innovative design is proposed as prelude to the meaningful agent communication and knowledge reuse for collaborative work among multidisciplinary organizations. A model for innovative design is proposed at first, based on which a knowledge schema is brought forward. For sharing the design knowledge among an internet-based or distributed work team, even globally, A RDF-based knowledge model is presented to realize its representation on Semantic Web. A Semantic Web based repository for innovative design and its API for topper Semantic Web applications have been also constructed. The proposed knowledge modeling extends traditional product modeling with capabilities of innovative design, knowledge sharing and distributed problem solving, and is employed as a content language within the messages in the proposed multi-agent system architecture. The proposed approach is viewed as a promising knowledge management method that facilitates the implementation of computer supported cooperative work in innovative design of Semantic Web applications.     

复制式协同特征造型中并发控制的研究*

一个好的并发控制方法应在操作不发生冲突的同时具有最大限度的并发度。针对复制式协同设计提出了一种基于特征依赖关系的自适应粒度的并发控制方法,极大地提高了协同设计的并发度,最后采用C++编程语言结合WinSocket技术建立一个实现该并发控制方法的协同特征造型系统。     

Designing peer-to-peer distributed user interfaces: Case studies on building distributed applications

Building a distributed user interface (DUI) application should ideally not require any additional effort beyond that necessary to build a non-distributed interface. In practice, however, DUI development is fraught with several technical challenges such as synchronization, resource management, and data transfer. In this paper, we present three case studies on building distributed user interface applications: a distributed media player for multiple displays and controls, a collaborative search system integrating a tabletop and mobile devices, and a multiplayer Tetris game for multi-surface use. While there exist several possible network architectures for such applications, our particular approach focuses on peer-to-peer (P2P) architectures. This focus leads to a number of challenges and opportunities. Drawing from these studies, we derive general challenges for P2P DUI development in terms of design, architecture, and implementation. We conclude with some general guidelines for practical DUI application development using peer-to-peer architectures.     

Development of a multi-agent-based distributed simulation platform for semiconductor manufacturing

Since the semiconductor manufacturing system is a large-scale complex system, it is difficult to solve complex problems in semiconductor manufacturing by the mathematical modeling method. This paper presents a multi-agent-based distributed simulation platform to support the extremely complex semiconductor manufacturing analysis. A multi-agent-based distributed simulation platform framework and a multi-agent collaborative control model are proposed to provide a flexible infrastructure and a multi-agent coordination mechanism in distributed environment for semiconductor manufacturing simulation. A multi-agent time synchronization model for distributed simulation is designed to keep events in the correct logical time order in simulation and steps of time synchronization are given. An interaction model and message formats are presented to describe how agents communicate with each other in simulation. The platform development and the design of graphical user interface are also exploited in this paper. Finally, evaluation of this multi-agent-based platform was illustrated with a case study. It indicates that the platform is effective in modeling and simulating the complex semiconductor manufacturing and provides the insights about how to improve the semiconductor manufacturing process with well targeted measures.     

Mobile-agent-based collaborative sensor fusion

Information fusion can assist in the development of sensor network applications by merging capabilities, raw data and decisions from multiple sensors through distributed and collaborative integration algorithms. In this paper, we introduce a multi-layered, middleware-driven, multi-agent, interoperable architecture for distributed sensor networks that bridges the gap between the programmable application layer consisting of software agents and the physical layer consisting of sensor nodes. We adopt an energy-efficient, fault-tolerant approach for collaborative information processing among multiple sensor nodes using a mobile-agent-based computing model. In this model the sink/base-station deploys mobile agents that migrate from node to node following a certain itinerary, either pre-determined or determined on-the-fly, and fuse the information/data locally at each node. This way, the intelligence is distributed throughout the network edge and communication cost is reduced to make the sensor network energy-efficient. We evaluate the performance of our mobile-agent-based approach as well as that of the traditional client/server-based computing model, vis-à-vis energy consumption and execution time, through both analytical study and simulation. We draw important conclusions based on our findings. Finally, we consider a collaborative target classification application, supported by our architectural framework, to illustrate the efficacy of the mobile-agent-based computing model.     

.面向协同系统集成的数据同步模型*

为了在系统协同工作过程中使异构数据库的数据同步,基于agent技术给出了一个数据同步模型。在该模型中,agent的局部代理利用数据同步监听器对数据的变化进行实时监听,全局代理利用数据同步检测器对数据是否同步进行定期检测,并生成相应的同步命令由全局代理分发执行,解决了协同系统中异构数据库的数据同步问题。最后,该模型应用到一个"项目控制管理系统"中,说明了该模型的可用性和有效性以及数据同步机制的正确性和实时性。