工程设计数据库管理中版本模型的研究

版本管理是工程数据库管理中的重要部分,也是保证设计数据一致的手段。文中提出了设计对象的概念,以设计对象为基础组织和描述完整的产品设计信息,建立了设计对象之间的组合联系、等价联系以及版本联系,提出了设计对象的层次模型表示方法。针对工程数据管理的特点建立了其版本机制,提出了设计对版本历史、对象版本之间的联系等概念,研究了设计对象的版本操作－检入／检出、当前版本的选择以及版本的动态配置等主要内容。     

A structured methodology for implementing engineering data management

One of the most significant positive effects on product and process development in recent years has been the application of data management techniques. Engineering data management or product data management is the most promising one. The implementation of engineering data management is heavily dependent on the engineering process and involves the technologies of management, engineering, and information. However, as there is no commonly acceptable approach and methodologies for implementing engineering data management, it’s implementation becomes a bottleneck.This paper presents a structured methodology for the implementation of engineering data management. The approach consists of a series of steps, from business and engineering process analysis, modeling and reengineering, through system design and modeling, to system realization.This research will facilitate engineering process improvement and the planning, design and implementation of engineering data management. Consequently, it will help increase product development capability and quality, reduce development cycle time and cost, and hence increase product marketability.     

Applying software engineering techniques in the development and management of linear and integer programming applications

This work addresses characteristics of software environments for mathematical modeling and proposes a system for developing and managing models of linear and integer programming (IP) problems. The main features of this modeling environment are: version control of models and data; client‐server architecture, which allows the interaction among modelers and decision makers; the use of a database to store information about the models and data scenarios; and the use of remote servers of optimization, which allows the optimization problems to be solved on different machines. The modeling environment proposed in this work was validated using mathematical programming models that exploit different characteristics, such as the treatment of conditions for generating variables and constraints, the use of calculated parameters derived from other parameters, and the use of integer and continuous variables in mixed IP models among others. This validation showed that the proposed environment is able to treat models found in various application areas of operations research and to solve problems with tens of thousands of variables and constraints.     

工程数据库动态版本管理模型的研究

本文研究了工程数据库中动态版本管理模型及实现方法,包括设计版本管理,约束及约束传递与控制,版本一致性的管理与控制,完成版的判定等动态版本管理中的基本问题.介绍了一个已投入使用的动态版本管理系统DVMS的结构和设计思想.     

From engineering diagrams to engineering models: Visual recognition and applications

We present a computational recognition approach to convert network-like, image-based engineering diagrams into engineering models with which computations of interests, such as CAD modeling, simulation, information retrieval and semantic-aware editing, are enabled. The proposed approach is designed to work on diagrams produced using computer-aided drawing tools or hand sketches, and does not rely on temporal information for recognition. Our approach leverages a Convolutional Neural Network (CNN) as a trainable engineering symbol recognizer. The CNN is capable of learning the visual features of the defined symbol categories from a few user-supplied prototypical diagrams and a set of synthetically generated training samples. When deployed, the trained CNN is applied either to the entire input diagram using a multi-scale sliding window or, where applicable, to each isolated pixel cluster obtained through Connected Component Analysis (CCA). Then the connectivity between the detected symbols are analyzed to obtain an attributed graph representing the engineering model conveyed by the diagram. We evaluate the performance of the approach with benchmark datasets and demonstrate its utility in different application scenarios, including the construction and simulation of control system or mechanical vibratory system models from hand-sketched or camera-captured images, content-based image retrieval for resonant circuits and sematic-aware image editing for floor plans.     

The ROSE data manager: using object technology to supportinteractive engineering applications

The relational object system for engineering (ROSE) is an experimental database system for interactive engineering applications. The ROSE system and the way it uses object technology are described. The system has an open architecture which allows new tools to be added easily. Several tools are described, including an inheritance manager, version control system, and user interface manager. These tools enhance the ROSE system and broaden its application to other types of data-management problems     

Parameter mapping and data transformation for engineering application integration

Enterprise applications may be classified into management applications used by managerial staffs for making decisions on business operations, and engineering applications used by engineers for solving multidisciplinary design problems. In the literature, enterprise application integration is extensively addressed in the context of management applications, but insufficiently discussed in the engineering disciplines. Practitioners in manufacturing industries have for a long time feel the increasing need of integrating engineering applications, in order to accelerate product development paces and improve design qualities. Integrating engineering applications used in the multiple engineering disciplines has to cope with a number of challenges. This paper focuses on one of the critical issues: parameter mapping and data transformation, which is of pivotal importance to integrating engineering applications. Design parameter mapping provides a consistent approach to data extraction, storage, display and manipulation among different data sources. Data transformation describes the operational logic of parsing input/output files, extracting and transforming data, and maintaining consistency among multiple data sources.

A model-driven approach to semi-structured database design

Recently XML has become a standard for data representation and the preferred method of encoding structured data for exchange over the Internet. Moreover it is frequently used as a logical format to store structured and semi-structured data in databases. We propose a model-driven and configurable approach for modeling hierarchical XML data using object role modeling (ORM) as a flat conceptual model. First a non-hierarchical conceptual schema of the problem domain is built using ORM and then different hierarchical views of the conceptual schema or parts of it are specified by the designer using transformation rules. A hierarchical modeling notation called H-ORM is proposed to show these hierarchical views and model more complex semi-structured data constructs and constraints. We also propose an algorithm to map hierarchical H-ORM views to XML schema language.     

A control system proposal for engineering education

The goal of the work is to improve the teaching–learning process through the inclusion of prediction features in a control system proposal namely Reactive Blended Learning. To achieve this goal, a model of the student has been proposed, whose considered outputs are the performance and a participation index that measures the activity level of the student in the class. The controller is based on fuzzy logic and uses the predictions of the model to anticipate the student's state.An important issue that has been taken into account is the limited time to identify the dynamics of the student learning before the course ends. This limitation has been treated through a three-stage process. It is important to remark that this work is not focused on obtaining a complete student model, but on getting useful information for the detection of trends in the teaching–learning process. Preliminary results on a real course are presented to attest the efficiency of the proposed control strategy.     

Feature‐based approach to object‐oriented engineering of applications for reuse

Object‐oriented technology is gaining popularity among software engineers with the goal of building reusable and adaptable software. Unfortunately, however, most methods introduced so far are not domain‐oriented and do not address the issue of reuse directly. For these methods, software reuse is not the primary goal; it is only a by‐product. The feature‐oriented reuse method, FORM, is extended in this paper for improving the object‐oriented engineering of applications for reuse. FORM concentrates on analyzing and modeling commonalities and differences in the applications of a given domain in terms of capability, operating environment, domain technology, and implementation technique features. These features are used to systematically derive objects that are tied to the features, and to develop reusable and adaptable domain architectures. We found that FORM facilitates analysis of variability (and commonality) of software before engineering and implementation start, and with this understanding, adaptability and reusability can be built into software. Feature modeling has been found to be an effective method for identifying and modeling reusable objects. Copyright © 2000 John Wiley & Sons, Ltd.     

Autonomous objects: A natural model for complex applications

Object-oriented database systems are emerging as the next generation DBMSs for advanced applications, e.g., VLSI design, mechanical CAD/CAM, software engineering, etc. However, a close analysis indicates that the requirements imposed by these application domains cannot be met by an object-oriented model that relies purely onpassive objects. In this work we go beyond the conventionalsingle-thread-of-control paradigm of passive object models and propose a model ofactive objects which can autonomously initiate responses to environmental changes.Autonomous objects cooperate with each other by synchronous orasynchronous message passing—giving rise to themultiple-thread-of-control in such an environment. It is shown howevents—to which active objects react—can be incorporated into this model. We propose a nondeterministic computational model for the individual active objects that allows the autonomous reaction upon events. We show that this very sparse extension to an object-oriented model gives rise to several high-level features which can be controlled by events. The object-oriented paradigm allows one to isolate the rules according to which events are being raised. This leads to a potentially rather efficient execution model compared to existing relational concepts, which are typically globally-defined event trigger mechanisms.     

一种实时事务并发控制的新方法:SMVCC

提出了新颖的实时数据库事务并发控制方法：语义多版本并发控制协议（SMVCC）。利用实时数据库中存在多版本数据的特点,考虑实时数据和实时事务语义,结合实时数据库相似性概念,对传统多版本并发控制方法进行扩展,对不同事务采用不同并发控制策略,提高了事务并发度。     

A step toward STEP-compatible engineering data management: the data models of product structure and engineering changes

In an iterative design process, there is a large amount of engineering data to be processed. Well-managed engineering data can ensure the competitiveness of companies in the competitive market. It has been recognized that a product data model is the basis for establishing engineering database. To fully support the complete product data representation in its life cycle, an international product data representation and exchange standard, STEP, is applied to model the representation of a product. In this paper, the architecture of an engineering data management (EDM) system is described, which consists of an integrated product database. There are six STEP-compatible data models constructed to demonstrate the integratibility of EDM system using common data modeling format. These data models are product definition, product structure, shape representation, engineering change, approval, and production scheduling. These data models are defined according to the integrated resources of STEP/ISO 10303 (Parts 41-44), which support a complete product information representation and a standard data format. Thus, application systems, such as CAD/CAM and MRP systems, can interact with the EDM system by accessing the database based on the STEP data exchange standard.     

Object versioning in an ODMG‐compliant object database system

In this paper, we describe the design and implementation of the SOP Object Version System which is built upon an object database system, called SOP (SNU ODBMS Platform). SOP is fully compliant with ODMG‐93, a standard for object databases proposed by the Object Database Management Group (ODMG). To support object versioning in an ODMG C++ OML (Object Manipulation Language) environment, the SOP Object Version System provides a set of APIs (Application Programming Interfaces) as a class library. One important design goal of the SOP Object Version System was to achieve full compliance with ODMG‐93 standard. That is, in designing the class library, we tried to utilize the ODMG‐93 C++ OML interface as much as possible, while preserving its semantics as defined in ODMG‐93. Our object version model follows the basic functionalities of mainstream object version models. Although this approach burdens programmers with the management of the application‐specific version policy, it helps users to apply the SOP Object Version System to diverse application areas. Copyright © 1999 John Wiley & Sons, Ltd.     

A new programming paradigm for engineering design software

Currently available programming and database systems are insufficient for engineering applications. The authors contend that a logical progression from a formal conceptual model of the engineering domain to a computational model will lead to new programming paradigms capable of directly supporting engineering applications in a rigorous, concise manner. A formal domain model devised by the authors, theHybrid Model (HM) of design information, is briefly introduced. It is an extension of axiomatic set theory and is discussed in detail elsewhere. HM forms the basis ofDesigner, a prototype-based object-oriented programming language supporting a signature-based canonical message-passing mechanism and multiple inheritance. Designer is implemented using the Scheme programming language. Because Designer satisfies a formal conceptual model, and because it is based on a formally specified language, its robustness and logical validity are superior to those of other languages not founded on formal principles. Designer combines concepts of functional and object-oriented programming to provide the formal rigor and flexibility to capture the complex and strongly interrelated information that designers use. Examples demonstrate how Designer represents design information. The results of the authors' research indicate that Designer can capture design information (including aspects of functional requirements and design intent) effectively and efficiently.     

Integration of engineering change objects in product data management databases to support engineering change analysis

This study proposes a product data management (PDM) database that can support engineering change analysis (ECA). It can integrate ECA with the existing main product development process managed by PDM systems. Since engineering change (EC) history is a key EC data element that enables ECA, this study extends PDM databases to represent the EC history with existing entities for ECs and associated products and their product structures. To show the feasibility of the proposed PDM database, this study integrates a prototype PDM system with on-line analytical processing (OLAP) tools and a data mining module for ECA. It also applies the implemented tools to two typical ECA applications, EC evaluation and EC propagation problems. The illustrative application examples show that the proposed PDM database can support ECA through multidimensional data analysis with OLAP and data mining with association rules.     

Design criteria for functional data bases

A functional data base is characterized as a collection of functions and its language as a collection of operators. The data base design criteria are established in terms of the functional properties, “redundancy” and “semantic content”. The behavior of data base operators is analyzed under these criteria to detect redundancies and compute the semantic content of a data model, to evaluate and compare data models. The correspondence between these criteria and the relational normalization theory is established.     

A four-step model for diagnosing knowledge transfer challenges from operations into engineering design

Knowledge gained from operations can help optimize the design of new installations in terms of system performance, health, and safety. Transferring such knowledge to engineering design teams makes it available for use in projects. However, the transfer involves different challenges. To better understand and identify these challenges, we combine a knowledge transfer model with a work systems model into the development of a conceptual four-step model for knowledge transfer from operations to engineering design. Knowledge transfer implies that the knowledge must be captured, transformed into an engineering design context, transferred to the appropriate individuals, and finally, applied to the design of new facilities. In this paper, we 1) present the development of this model, 2) illustrate its application in an empirical case study in an offshore oil company, and 3) propose a generic diagnostic tool to be applied in companies to diagnose and identify the existing challenges within knowledge transfer from operations to engineering design.Relevance to industryThe proposed diagnostic tool allows for better understanding of design problems to be faced and for developing design solutions that improve health, safety, and production effectiveness. This benefits knowledge management and engineering design professionals in industries with geographically dispersed organizations.     

Database support for solid modeling

Geometric solid modeling plays one of the most important roles in CAE (Computer Aided Engineering) activities. In order that geometric solid modeling functions sufficiently in the CAE environment, an EDBMS (Engineering Database Management System) supporting solid modeling is highly desirable. In this paper we present a new approach to the design of a geometric solid database system. In the proposed approach an EDBMS with capability of object-oriented accessing and manipulation is developed, and a solid sharing model that is a scheme for representing and manipulating a collection of interrelated solids is proposed. The solid sharing model is used as a basis for designing and manipulating a solid database managed by the EDBMS. Also explored is a mechanism for supporting a long transaction which generates many intermediate designs.