David L. Spooner

Sharing manufacturing information in virtual enterprises

ecent advances in communications technology make it possible for manufacturers to transmit data to each other in fractions of a second. However, if these corporations do not use the same software tools, understanding of the data can be delayed for weeks or months while employees purchase and learn to use new tools. This article describes ongoing research into an information infrastructure that seeks to use standards (formal and de facto) to reduce the problems that occur when manufacturers want to use different tools to process each other’s data. Communicating information between different software tools is a problem common to many application domains. For example, many researchers who have collaborated on research projects are familiar with arguments over which word processor to use for a particular project. In manufacturing, the multifaceted nature of design information makes communications particularly difficult. A mechanical design may contain geometric, tolerance, material, process control, and many other kinds of information. An information infrastructure is needed to allow manufacturing applications to communicate efficiently. The infrastructure should allow engineers to use familiar applications whenever possible. A successful infrastructure will reduce the time to market for new products while letting multiple organizations apply their specialties to product development. Manufacturing has a long history of reducing communications problems through standards. Some of the most significant advances in the industrial revolution occurred when standards were established. For example, drafting standards for drawings represented a significant contribution in the 18th and early 19th centuries. In the modern era, electronic communications are more important every year. Standards are needed so manufacturers can communicate efficiently through the Internet. The required standards are becoming increasingly complex as the range of information the industry wants to communicate becomes wider. Demand for these standards is increased by the desire to allow corporations to communicate in virtual enterprises.

Automatic Generation of Floating-Point Test Data

For numerical programs, or more generally for programs with floating-point data, it may be that large savings of time and storage are made possible by using numerical maximization methods instead of symbolic execution to generate test data. Two examples, a matrix factorization subroutine and a sorting method, illustrate the types of data generation problems that can be successfully treated with such maximization techniques.

Data protocols for the industrial virtual enterprise

High performance computer networks allow companies to share data and technology electronically and thus collaborate in virtual enterprises. One barrier to such collaboration is the lack of interoperability among the application systems of different companies-the data produced by the systems at one company cannot be read by those at another. The National Industrial Information Infrastructure Protocols (NIIP) Consortium was formed to address this problem. The article describes three layered protocols being developed by the NIIP data protocol team.

The ROSE data manager: using object technology to support interactive 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. >

Software for roundoff analysis, II

Many roundoff analyses of nomteratlve methods from numerical linear algebra can be performed, at least in part, using off-the-shelf software. Such software is presented here and its use is illustrated with examples. The package presented differs from Its predecessor in four important respects. First, a mmicompfler allows easy specIficatmn of the algorithm being tested. Second, the package can test the simultaneous effect of rounding error upon several values. Third, it deals with branching in numerical methods, e.g. with pivoting in Gaussian elimination. Fourth, m addition to comparing rounding error with perturbations of the problem, it can directly compare rounding errors in two competing algorithms

Adaptive integrated manufacturing enterprises: information technology for the next decade

A new vision effecting adaptiveness in integrated manufacturing enterprises for the next decade is formulated. This vision has been developed on the basis of intensive research over the past nine years in Rensselaers industry-sponsored Computer Integrated Manufacturing Program. Built from existing results in both the scientific community and industry, the proposed research agenda calls for new fundamental information technology to enable Adaptive Integrated Manufacturing Enterprises (AIME). It focuses on four major problems: (1) management of multiple systems that operate concurrently over a widely distributed network without a central controller; (2) achievement of an open systems architecture that can accommodate legacy systems as well as add new systems; (3) exploitation of object-oriented technology in production systems with the crucial ability to manage heterogeneous views and propagate changes between views; and (4) modeling of enterprise information requirements for inspection and the utilization of inspection information to create a feedback loop from production to design. These problems and approaches to their solution developed are analyzed. >

Modeling mechanical CAD data with data abstraction and object-oriented techniques

This paper focuses on the problem of management of CAD data by investigating the use of the software engineering principles of data abstraction and object-oriented programming as means for managing the volume and complexity of design data. It discusses how a data management system which manages abstract data types provides a framework for integrating a CAD environment by providing a single mechanism to manage data, programs, and the manipulation of the data with the programs. It also shows how two forms of abstraction, aggregation and generalization, can be used to model hierarchies of parts and components, and multiple design alternatives, respectively. These abstractions are then used to model the geometrical and topological data required to describe three-dimensional mechanical parts.

Using views for product data exchange

Proprietary data structures complicate data sharing by making it difficult to save a product model from one software tool and load it directly into another tool. Engineers may want, for example, to verify with an analysis tool that all design constraints have been met or to prepare a design for manufacturing. In such cases, software developers must find a means of moving the product model from the proprietary data structures of a CAD system to those of the analysis system and the manufacturing system, with minimal loss of information. A database view, used in conjunction with data exchange standards, can facilitate the sharing of product model data between software tools in design and manufacturing computing environments.

Lessons learned developing protocols for the industrial virtual enterprise

Abstract The protocols selected and developed by the NIIIP Consortium have been validated in three end-of-cycle demonstrations. In each cycle, a team with expertise in technical product data, object modeling, workflow management, security, and knowledge representation came together and demonstrated how technical barriers to the dynamic creation, operation and dissolution of “virtual enterprises” are overcome by the NIII protocols. This paper describes the protocols that were selected and developed by the product data team and makes predictions about how they will affect the future development and deployment of standard product data.

Concurrent engineering with delta files

We describe a test system in which we used a data management system and delta files to communicate engineering changes between two modeling systems: an ACIS-based solid modeling system running on a Sun Sparc workstation to create a part, and a CATIA system running on an IBM RS/6000 to design a fixture for it. The test system communicates the first version of the MBB part between the two engineers as a PDES/STEP (Product Data Exchange Standard/Standard for the Exchange of Product-Model Data) exchange file. The ACIS engineer then makes an engineering change to the part, thus creating, the second version (V2) of it, and a delta file communicates the V2 changes to the CATIA engineer. The CATIA engineer can use this delta file to highlight the changes to the part between the two versions. Although our test system/scenario is simple, it demonstrates the advantages of delta files. It also helped us identify several important issues for developing the method further. We first outline the STEP standard and how we used it to implement data exchange in our test system, then we discuss delta files and describe how we implemented them. We conclude with a discussion of the lessons learned from the test system and scenario. >