James K. McDowell

Multiple Design: An Extension of Routine Design for Generating Multiple Design Alternatives

Many engineering design situations require the generation of multiple designs to meet a common set of specifications. This research introduces an effective approach for generating multiple designs. The method developed utilizes and builds on the generic task approach to knowledge-based systems, as well as the specific design technique, known as Routine Design.

FUNCTION-BASED MODELING AND TROUBLESHOOTING

Abstract This report describes an ongoing effort to apply the functional modeling (FM) approach to the representation of and reasoning about engineered artifacts. The application domain is the external active thermal control system (EATCS) of space station Freedom. The intuitions behind FM are threefold. First, knowing the purposes of a device allows organization of the causal understanding of how a device works. Second, causality may be represented in modular chunks, which are indexed by the purposes of the device and its interrelated subsystems. Finally, the global behavior of a device in a given situation can be understood by composition of the relevant causal net fragments. These starting intuitions provide a framework for organizing calculations about a device and for performing a limited type of simulation with the organized ensemble. Parallel to the FM modeling effort for EATCS is the development of a methodology that generates diagnostic knowledge for a device directly from its FM representation. ...

Integrating material/part/process design for polymer composites: A knowledge-based problem-solving approach

Polymer composites provide the opportunity to design the material as well as the part. The domain for composites design can be viewed along three dimensions, namely material design, part design, and process design. These dimensions are not independent, and their interactions create important bottlenecks in manufacturing. Integrating these material/part/process issues becomes increasingly important as composite materials penetrate the durable goods markets and as high-performance markets become more and more cost conscious. Often these bottlenecks are caused by lack of strategic knowledge or the application of knowledge in the wrong context. To address these challenges and facilitate the use of polymer composites, a problem-solving architecture for integrated material/part/process design is being developed that makes use of knowledge-based systems (KBS) technology. The goal is to bring to bear the necessary decision-making knowledge at important junctions in the design procedure. Our current implementations include a system for material design and a system for elementary process design in the form of process technology selection. These systems and the problem-solving architecture are founded on a particular approach to KBS known as Generic Task Theory. These software systems are described in terms of their behavior, the underlying domain assumptions, and the knowledge representation constructs and inferences used in design problem solving.

Virtual Prototyping in Polymer Composites

Polymer composites have no standardized design procedure that guides a conscientious consideration of the multiple interactions among materials, manufacturing, and geometry. Intelligent decision support systems can enable such considerations during the critical conceptual design phase, where function and general structure are more significant than detailed geometry. This paper focuses on the knowledge representation and inference strategies in an intelligent decision support system for the conceptual design of polymer composite assemblies. The conceptualized function and structure of an assembly are represented in functional and configuration knowledge models. The specific domain application is retrofitting an existing metal assembly using polymer composite materials.

Troubleshooting based on a functional device representation: diagnosing faults in the external active thermal control system of Space Station Freedom

This report describes an ongoing effort to apply the functional modeling (FM) approach to the representation of and reasoning about engineered artifacts. The application domain is the external active thermal control system (EATCS) of the FREEDOM space station. The intuitions behind FM are threefold. First, knowing the purposes of a device allows organization of the causal understanding of how a device works. Second, in FM, causality is represented in modular chunks which are indexed by the purposes of the device and its interrelated subsystems. Finally, the global behavior of a device in a given situation can be understood by composition of the relevant causal net fragments. These starting intuitions provide a framework for organizing calculations about a device and for performing a limited type of simulation with the organized ensemble.

Socharis: The instantiation of a strategy for conceptual manufacturing planning

Considering manufacturing expertise during the early stages of design can be of great benefit. Such information can greatly improve not only the quality of a design, but it can also ensure the generation of an easily manufactured design. This, in turn, can lower the final cost of the designed product. By evaluating how easily an evolving conceptual design can be made, potential hazards can be avoided before any detailed design efforts commence. The conceptual manufacturing planning requisite to such an evaluation is the focus of this paper. A domain-independent strategy for conceptual manufacturing planning is presented. A task-structure analysis of this strategy shows its domain independence. A specific implementation of this strategy for polymer composites manufacturing planning (Socharis) is discussed. The high-level implementation details of Socharis are presented as instantiations of the conceptual manufacturing planning strategy. Finally, the validity of the planning strategy and the utility of Socharis are assessed.

A decision support architecture for polymer composites design: implementations and evolution

Herein lies a tour through the development of an architecture for polymer composite material design. The initial structure of the architecture is presented along with its underlying ideas. Being preliminary, this system was confined in its coverage of the domain, leading to the expansion of coverage in the next generation. However, it was realized that this implementation as well as the ideology behind it were incapable of fully addressing the complexities of material design. A methodology/ideology demarcation line can be drawn at this point, as the next system implemented a new approach called multiple design. With essentially the same depth as the previous system, this new system generated a family of designs, instead of the first best design. The most recent system was then implemented to substantially increase the domain coverage and fine-tune the knowledge organization. Throughout the growth and development of the material design methodology, the overall vision for polymer composites design has evolved as well.<<ETX>>

Task structure: a vocabulary for integrating numerical methods and knowledge-based systems

Often Expert Systems (ES) or Knowledge-based Systems (KBS) are described in term of their implementation details. If the complex problem solving activities captured in such systems are viewed as a type of information processing ask then an alternative vocabulary of description is possible which is more suitable for systems design. This vocabulary is called the ‘Task Structure’. Since engineering problem solving is not entirely symbolic and sophisticated numerical computations need to be performed to determine physical system parameters, a KBS in that problem solving environment needs to be integrated with computational procedures for successful application. This paper describes the organization of numeric computation using a Task Structure vocabulary and demonstrates its potential as a viable tool for integration of numerical methods with KBS.

Knowledge Management for the Strategie Design and Manufacture of Polymer Composite Products

A corporate knowledge handling strategy should permeate an organization, but the design and manufacturing arenas are especially important. Considering the design and manufacturing activities holistically and conceptually promotes strategic application of knowledge. The holistic approach allows the consideration of issues from all dimensions and avoids decision making in a vacuum. A conceptual approach allows the suppression of detail, providing relevance and clarity. The idea is not to control technologists at the preliminary phases but to dispense focused and structured decision making knowledge. Such a knowledge management approach can facilitate successful product development without hindering creativity or needlessly restricting product descriptions. This discussion takes these themes and integrates them with knowledge systems philosophies into a vision for strategic knowledge management. Specifically, this vision is applied to the design and manufacturing of polymer composite products.