Real-time collaborative design based on operation semantics in distributed CAD environment

This paper proposes a collaborative design model based on operation semantics in a distributed computer-aided design (CAD) environment. The goal is to reduce time consumption in data format conversion and the requirement of network bandwidth so as to improve the cooperative ability and the synchronization efficiency. Firstly, real-time collaborative design is reviewed and three kinds of real-time collaborative design models are discussed. Secondly, the concept of operation semantics is defined and the framework of an operation semantics model is presented. The operation semantics carries the original design data and actual operation process to express design intent and operation activity in conventional CAD systems. Finally, according to the operation semantics model, a CAD operation primitive is defined which can be retrieved from and mapped to the local CAD system operation commands; a distributed CAD collaborative architecture based on the model is presented, and an example is given to verify the model.

A Task-oriented Modular and Agent-based Collaborative Design Mechanism for Distributed Product Development

The rapid expansion of enterprises makes product collaborative design （PCD） a critical issue under the distributed heterogeneous environment, but as the collaborative task of large-scale network becomes more complicated, neither unified task decomposition and allocation methodology nor Agent-based network management platform can satisfy the increasing demands. In this paper, to meet requirements of PCD for distributed product development, a collaborative design mechanism based on the thought of modularity and the Agent technology is presented. First, the top-down 4-tier process model based on task-oriented modular and Agent is constructed for PCD after analyzing the mapping relationships between requirements and functions in the collaborative design. Second, on basis of sub-task decomposition for PCD based on a mixed method, the mathematic model of task-oriented modular based on multi-objective optimization is established to maximize the module cohesion degree and minimize the module coupling degree, while considering the module executable degree as a restriction. The mathematic model is optimized and simulated by the modified PSO, and the decomposed modules are obtained. Finally, the Agent structure model for collaborative design is put forward, and the optimism matching Agents are selected by using similarity algorithm to implement different task-modules by the integrated reasoning and decision-making mechanism with the behavioral model of collaborative design Agents. With the results of experimental studies for automobile collaborative design, the feasibility and efficiency of this methodology of task-oriented modular and Agent-based collaborative design in the distributed heterogeneous environment are verified. On this basis, an integrative automobile collaborative R＆D platform is developed. This research provides an effective platform for automobile manufacturing enterprises to achieve PCD, and helps to promote product numeralization collaborative R＆D and management development.

MULTI-AGENT COLLABORATIVE DESIGN SYSTEM MODEL BASED ON THE INTERNET AND EXPERIMENTS

Development of complicated products is a project of system engineering It involves extensive and complicated knowledge,design methods and auxiliary technology Various factors affect each other So,modern product development is a typical group problem with distributed and dynamic features It is apparent superiority to solve this problem with a multi agent system representing various knowledge domains Distributed artificial intelligence knowledge being used,the multi agent collaborative design system concept and model based on Internet environment are put forward The realizing method of product developing agents,interactive process among multi agents,and organization and implementing of the design project of the multi agent collaborative design system are discussed in detail Application examples are also presented.

Application of the optimal Latin hypercube design and radial basis function network to collaborative optimization

Improving the efficiency of ship optimization is crucial for modem ship design. Compared with traditional methods, multidisciplinary design optimization （MDO） is a more promising approach. For this reason, Collaborative Optimization （CO） is discussed and analyzed in this paper. As one of the most frequently applied MDO methods, CO promotes autonomy of disciplines while providing a coordinating mechanism guaranteeing progress toward an optimum and maintaining interdisciplinary compatibility. However, there are some difficulties in applying the conventional CO method, such as difficulties in choosing an initial point and tremendous computational requirements. For the purpose of overcoming these problems, optimal Latin hypercube design and Radial basis function network were applied to CO. Optimal Latin hypercube design is a modified Latin Hypercube design. Radial basis function network approximates the optimization model, and is updated during the optimization process to improve accuracy. It is shown by examples that the computing efficiency and robustness of this CO method are higher than with the conventional CO method.

Maturity assessment model for aircraft collaborative design software solution

In order to assure quality and control process in the development of the aircraft collaborative design software, a maturity assessment model is proposed. The requirements designing—house of quality is designed to evaluate the maturity degree of the solution, and the evaluation results can help to manage and control the development process. Furthermore, a fuzzy evaluation method based on the minimum deviation is proposed to deal with the fuzzy information. The quantitative evaluation result of the maturity degree can be calculated by optimizing the semantic discount factor aim for the minimum deviation. Finally, this model is illustrated and analyzed by an example study of the aircraft collaborative design software.

COLLABORATIVE DESIGN OF MULTIPHYSICS PROBLEMS

Collaborative design is recommended to solve multiphysics problems （MPPS）. Firstly, mathematical model of MPPS is constructed and solved by a proposed partitioned method, analysis of which suggests that collaborative design be feasible to solve MPPS. As the key technology of col-laborative design of MPPS, a task collaboration algorithm is then proposed. To develop the applica-tion framework of collaborative design, applied unified process（AUP） is proposed based on rational unified process（RUP）. Then AUP is used to develop the collaborative design platform, whose function framework is constructed according to the process of project management. Finally three MPPS are solved on this platform and the results suggest that the proposed model, algorithm and framework be feasible.

Collaborative Design in PDM / 3D CAD Integrated Environment

Some key issues in supporting collaborative design in product data management（PDM ） system and 3D computer aided design（CAD） system integrated environment are analyzed. The general architecture of the integrated environment is divided into five tiers and employs the transparently integrated mode, with the mode, function calling and information exchanging among independent PDM and CAD processes are carried out via message translation /parse approach. Product layout feature（PLF ） model definition is presented, PLF model is used to represent design intention at the preliminary design phase. The collaborative design methodology employing the PLF model in PDM/3D CAD integrated environment is analyzed. The design methodology can speed up the design process, reduce the investment and improve the product quality.

Research on message resource optimization in computer supported collaborative design

An adaptive mechanism is presented to reduce bandwidth usage and to optimize the use of computing resources of heterogeneous computer mixes utilized in CSCD to reach the goal of collaborative design in distributed-synchronous mode. The mechanism is realized on a C/S architecture based on operation information sharing. Firstly, messages are aggregated into packets on the client. Secondly, an outgoing-message weight priority queue with traffic adjusting technique is cached on the server. Thirdly, an incoming-message queue is cached on the client. At last, the results of implementing the proposed scheme in a simple collaborative design environment are presented.

XML-based Data Processing in Network Supported Collaborative Design

In the course of network supported collaborative design, the data processing plays a very vital role. Much effort has been spent in this area, and many kinds of approaches have been proposed. Based on the correlative materials, this paper presents extensible markup language （XML） based strategy for several important problems of data processing in network supported collaborative design, such as the representation of standard for the exchange of product model data （STEP） with XML in the product information expression and the management of XML documents using relational database. The paper gives a detailed exposition on how to clarify the mapping between XML structure and the relationship database structure and how XML-QL queries can be translated into structured query language （SQL） queries. Finally, the structure of data processing system based on XML is presented.

Agent-based Collaborative Design Framework Supporting Synchronization and Asynchronization on Internet

On the basis of analysis of the research issues and requirement of collaborative design, we propose the overall framework of agent based collaborative design on Internet. Then, we describe the implementation of synchronous and asynchronous collaborative design process based on standardized design activities under the overall framework. In order to realize design message passing, the DMP Protocol is proposed as well in this paper and described in detail.

Evaluation and selection of the ship collaborative design resources based on AHP and genetic and simulated annealing algorithm

The characteristics of the design resources in the ship collaborative design is described and the hierarchical model for the evaluation of the design resources is established. The comprehensive evaluation of the co-designers for the collaborative design resources has been done from different aspects using Analytic Hierarchy Process （AHP） ,and according to the evaluation results,the candidates are determined. Meanwhile,based on the principle of minimum cost,and starting from the relations between the design tasks and the corresponding co-designers,the optimizing selection model of the collaborators is established and one novel genetic combined with simulated annealing algorithm is proposed to realize the optimization. It overcomes the defects of the genetic algorithm which may lead to the premature convergenee and local optimization if used individually. Through the application of this method in the ship collaborative design system,it proves the feasibility and provides a quantitative method for the optimizing selection of the design resources.

PERFORMANCE-BASED INTELLIGENT RESOURCE DESCRIPTION MODEL FOR INTERNET-BASED PRODUCT DESIGN

Issues on intelligent resource description and multiple intelligent resources integration for lntemet based collaborative design are analyzed. A performance-based intelligent resource description model for lnternet-based product design is proposed, which can help to create, store, manipulate and exchange intelligent resource description information for applications, tools and systems in Interact-based product design. A method to integrate multiple intelligent resources to fulfill a complex product design and analysis via lntemet is also proposed. A real project for improving the bearing system design of a turbo-expander with many intelligent resources in prominent universities is presented as a case study.

Multi-Stage Multidisciplinary Design Optimization Method for Enhancing Complete Artillery Internal Ballistic Firing Performance

To enhance the comprehensive performance of artillery internal ballistics—encompassing power,accuracy,and service life—this study proposed a multi-stage multidisciplinary design optimization(MS-MDO)method.First,the comprehensive artillery internal ballistic dynamics(AIBD)model,based on propellant combustion,rotation band engraving,projectile axial motion,and rifling wear models,was established and validated.This model was systematically decomposed into subsystems from a system engineering perspective.The study then detailed the MS-MDO methodology,which included Stage I(MDO stage)employing an improved collaborative optimization method for consistent design variables,and Stage II(Performance Optimization)focusing on the independent optimization of local design variables and performance metrics.The methodology was applied to the AIBD problem.Results demonstrated that the MS-MDO method in Stage I effectively reduced iteration and evaluation counts,thereby accelerating system-level convergence.Meanwhile,Stage II optimization markedly enhanced overall performance.These comprehensive evaluation results affirmed the effectiveness of the MS-MDO method.

Product Knowledge Representation and Integration Technology in Web-based Collaborative Design

Because of the complexity of modern product design,the web-based collaborative product design aroused considerable attention of manufacturers in the last few years with the development of Internet technology. But it is still hardly achievable due to the difficulty to share product knowledge from different designers and systems. In this paper,we firstly create an ontology-based product model,which consists of PPR (Product,Process and Resource) concept models and PPR characteristic models,to describe product knowledge. Afterwards,how to represent the model in XML is discussed in detail. Then the mechanism of product knowledge collection and integration from different application systems based on interface agents is introduced. At last,a web-based open-architecture product knowledge integrating and sharing prototype system AD-HUB is developed. An example is also given and it shows that the theory discussed in this paper is efficient to represent and integrate product knowledge in web-based collaborative design processes.

Research on conflict resolution of collaborative design with fuzzy case-based reasoning method

Collaborative design is a new style for modern mechanical design to meet the requirement of increasing competition. Designers of different places complete the same work, but the conflict appears in the process of design which may interface the design. Case-based reasoning (CBR) method is applied to the problem of conflict resolution, which is in the artificial intelligence field. However, due to the uncertainties in knowledge representation, attribute description, and similarity measures of CBR, it is very difficult to find the similar cases from case database. A fuzzy CBR method was proposed to solve the problem of conflict resolution in collaborative design. The process of fuzzy CBR was introduced. Based on the feature attributes and their relative weights determined by a fuzzy technique, a fuzzy CBR retrieving mechanism was developed to retrieve conflict resolution cases that tend to enhance the functions of the database. By indexing, calculating the weight and defuzzicating of the cases, the case similarity can be obtained. Then the case consistency was measured to keep the right result. Finally, the fuzzy CBR method for conflict resolution was demonstrated by means of a case study. The prototype system based on web is developed to illustrate the methodology.

An Approach to Collaborative Design Based on Distributed Constraint-Net

We focuse on design process in concurrent engineering and propose an, approach to collaborative design based on distributed constraint-net. The approach adopts agent technology to express kinds of distributed constraints. And through the cooperation among agents, the consistency of constraint is maintained and the constraint conflict is detected and eliminated. The constraints are satisfied concurrently and distributively. Based on the proposed approach, the collaborative design process in concurrent engineering can be well supported.

Research on Product Digital Collaborative Design System

Network economy had changed manufacturing environme nt at all. Open global market offer more choice to customer, and it become changea ble and unpredictable as consumers’ needs become more and more characteristic an d diversified. Various new technology coming forth and application accelerate th e rapid change of the market. The manufacturing enterprises were compelled t o change their strategy by the variability of the market, and time has been put to the all-important place. There is a need driven by the market to set up a ne twork design and manufacturing mode which have rapid market responsiveness. In order to meet the need for network manufacturing, the organization and manage ment of manufacturing enterprise need a completely innovation, next generation o f manufacturing system must have the character such as digitization, flexibility , agility, customization and globalization and so on. As for an enterprise in au to industry, how to gather together the orders through the distribution, and rap id produce the product which can meet the customer’s need, it is the key that th e contemporary enterprises succeed in the competitive market. The competitive market requires rapid product development. Close cooperation amo ng the designers will accelerate the product development by shortening the devel opment cycle, improving the product quality and reducing the investment. It has been emphasized in the methodology of concurrent engineering (CE). But sometimes those partners are distributed in the world, so there is a need for an importan t technology contribution to collaborative engineering, and supporting distribut ed designers for rapid product development. This paper focuses on a collaborative design system: Product Digit Collaborative Design System (PDCDS). The solution of PDCDS can make it more efficient and rel iable to visit teledata as well as we can get it from local database. It will be ease to get the newest design process information aided by PDCDS, and it will h ave higher efficiency by collaborative work. Comparing with other traditional Pr oduct Data Management (PDM) software system, PDCDS have some new characters such as group, dynamicness, synchronization or asynchronism working mode, and the hi story recorder is needed, and it also surport Webservice.

Conflict Resolution Based on Collaborative Design of Grid Services

To the issues of low efficiency of conflict resolution method in collaborative design, we proposed a method, which is conflict resolution about collaborative design based on grid services.It uses the grid services from the current design points, uses the method of retrospective thinking to find the conflict point by detecting, and then uses the corresponding method to resolve the conflict point according to the conflict characteristic, after that carried on the conflict detection again. If there is still the conflict, resolve the conflict point again, until the conflict no longer exists. This method combines various traditional resolution methods, makes full use of the grid idle high-performance large-scale sharing resources. With this method the collaborative design conflict resolution cost reduced and the conflict resolution efficiency was raised. And then the problem which is not handled completely was then solved, so that the conflict resolution Quality was guaranteed.

STUDY ON CONFLICT MANAGEMENT FOR COLLABORATIVE DESIGN SYSTEM

Modern day products are usually designed cooperatively by groups of experts, each with his own areas of expertise. Because of different viewpoint, evaluation standard and domain knowledge of these design groups in collaborative design system, conflict is unavoidable. In this paper, an integration conflict management system (ICMS) was presented from the aspect of all life cycle. A hierarchical constraint network was introduced to detect the conflicts. Three conflict types were classified in ICMS and different type of conflict was submitted to different resolution strategy, constraint relaxation to data conflict and knowlegdge based reasoning to knowledge conflict or schema conflict. To those conflicts hard to be resolved with the above two strategies, an arbitration was used for the conflict resolution. ICMS also provided interface with other collaborative systems such as CAE, CAD to improve the efficiency of collaborative design system.

Research and application of key technologies for data delivery in railway engineering design based on metadata

In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.