Ram D. Sriram

The evolution, challenges, and future of knowledge representation in product design systems

Product design is a highly involved, often ill-defined, complex and iterative process, and the needs and specifications of the required artifact get more refined only as the design process moves toward its goal. An effective computer support tool that helps the designer make better-informed decisions requires efficient knowledge representation schemes. In todays world, there is a virtual explosion in the amount of raw data available to the designer, and knowledge representation is critical in order to sift through this data and make sense of it. In addition, the need to stay competitive has shrunk product development time through the use of simultaneous and collaborative design processes, which depend on effective transfer of knowledge between teams. Finally, the awareness that decisions made early in the design process have a higher impact in terms of energy, cost, and sustainability, has resulted in the need to project knowledge typically required in the later stages of design to the earlier stages. Research in design rationale systems, product families, systems engineering, and ontology engineering has sought to capture knowledge from earlier product design decisions, from the breakdown of product functions and associated physical features, and from customer requirements and feedback reports. VR (Virtual reality) systems and multidisciplinary modeling have enabled the simulation of scenarios in the manufacture, assembly, and use of the product. This has helped capture vital knowledge from these stages of the product life and use it in design validation and testing. While there have been considerable and significant developments in knowledge capture and representation in product design, it is useful to sometimes review our position in the area, study the evolution of research in product design, and from past and current trends, try and foresee future developments. The goal of this paper is thus to review both our understanding of the field and the support tools that exist for the purpose, and identify the trends and possible directions research can evolve in the future.

The role of knowledge in next-generation product development systems

Information technology has played an increasingly important role in engineering productdevelopment. Its influence over the past decade has been accelerating and its impact inthe coming decade will undoubtedly be immense. This paper surveys several researchareas relating to knowledge representation, capture and retrieval, which will have agrowing influence on product development. Each of these areas could, on its own, providesufficient material for an entire survey paper. Unlike traditional survey papers, this paperdoes not attempt to provide a comprehensive review of a field of research from its incep-tion to the present. Rather, this paper aims to touch on a representative selection of recentdevelopments in these influential technical areas. The paper provides perspectives into thekinds of technologies that are emerging from rapidly expanding fields of research, anddiscusses challenges that must be overcome to enable transition of these technologies intoindustry practice to support the next generation of product development software tools.@DOI: 10.1115/1.1344238#

Ontology-based exchange of product data semantics

An increasing trend toward product development in a collaborative environment has resulted in the use of various software tools to enhance the product design. This requires a meaningful representation and exchange of product data semantics across different application domains. This paper proposes an ontology-based framework to enable such semantic interoperability. A standards-based approach is used to develop a Product Semantic Representation Language (PSRL). Formal description logic (DAML+OIL) is used to encode the PSRL. Mathematical logic and corresponding reasoning is used to determine semantic equivalences between an application ontology and the PSRL. The semantic equivalence matrix enables resolution of ambiguities created due to differences in syntaxes and meanings associated with terminologies in different application domains. Successful semantic interoperability will form the basis of seamless communication and thereby enable better integration of product development systems. Note to Practitioners-Semantic interoperability of product information refers to automating the exchange of meaning associated with the data, among information resources throughout the product development. This research is motivated by the problems in enabling such semantic interoperability. First, product information is formalized into an explicit, extensible, and comprehensive product semantics representation language (PSRL). The PSRL is open and based on standard W3C constructs. Next, in order to enable semantic translation, the paper describes a procedure to semi-automatically determine mappings between exactly equivalent concepts across representations of the interacting applications. The paper demonstrates that this approach to translation is feasible, but it has not yet been implemented commercially. Current limitations and the directions for further research are discussed. Future research addresses the determination of semantic similarities (not exact equivalences) between the interacting information resources.

Design repositories: engineering design's new knowledge base

Driven by pressure to reduce product development time, industry has started looking for new ways to exploit stores of engineering artifact knowledge. Engineers are increasingly turning to design repositories as knowledge bases to help them represent, capture, share and reuse corporate design knowledge. The paper discusses the NIST Design Repository Project.

The Role of Standards in Innovation

Abstract We review and explore the role of standards in innovation, with particular emphasis on design and manufacturing processes. We begin by defining and classifying standards and by exploring their role and infrastructure in society. This is followed by a similar discussion for innovation. By examining the relationships between innovation and standards, we extract the negative impact and the positive impact each has on the other. A study of four case histories in different domains—manufacturing, computer hardware, mechanical component design, and product data exchange—reveals that, as expected, standards are often derived from innovative technology. Surprisingly, however, innovation is often spurred—directly and indirectly—from standards as well. We conclude that, in general, the benefits of standards on innovation in design and manufacturing outweigh the possible limitations on creativity imposed by such standards.

Function-to-form mapping: model, representation and applications in design synthesis

Design of a new artifact begins with incomplete knowledge about the final product and the design evolves as it progresses from the conceptual design stage to a more detailed design. In this paper, an effort has been made to give a structural framework, through a set of generic definitions, to product specification, functional representation, artifact representation, artifact behavior and tolerance representation. A design synthesis process has been proposed for evolution of a product from the product specification. The proposed design synthesis method is a mapping from the functional requirements to artifacts, with multi-stage constrained optimization during stages of design evolution. Provisions have been kept to augment and/or modify the product specification and domain knowledge during stages of development to guide the design process. The effectiveness of the proposed design process has been illustrated with a simple design example based on a sample artifact library. An overall design scheme has been presented.

OntoSTEP: Enriching product model data using ontologies

The representation and management of product lifecycle information is critical to any manufacturing organization. Different modeling languages are used at different lifecycle stages, for example STEPs EXPRESS may be used at a detailed design stage, while UML may be used for initial design stages. It is necessary to consolidate product information created using these different languages to build a coherent knowledge base. In this paper, we present an approach to enable the translation of STEP schema and its instances to Ontology Web Language (OWL). This gives a model-which we call OntoSTEP-that can easily be integrated with any OWL ontologies to create a semantically rich model. As an example, we combine geometry information represented in STEP with non-geometry information, such as function and behavior, represented using the NISTs Core Product Model (CPM). A plug-in for Protege is developed to automate the different steps of the translation. As additional benefits, reasoning, inference procedures, and queries can be performed on enriched legacy CAD models. We describe the rules for the translation from EXPRESS to OWL, and illustrate the benefits of OWL translation with an example. We will also describe how these mapping rules can be implemented through meta-model based transformations, which can be used to map other languages to OWL.

A Model for Capturing Product Assembly Information

The important issue of mechanical assemblies has been a subject of intense research over the past several years. Most electromechanical products are assemblies of several components, for various technical as well as economic reasons. This paper provides an object-oriented definition of an assembly model called the Open Assembly Model (OAM) and defines an extension to the NIST Core Product Model (NIST-CPM). The assembly model represents the function, form, and behavior of the assembly and defines both a system level conceptual model and associated hierarchical relationships. The model provides a way for tolerance representation and propagation, kinematics representation, and engineering analysis at the system level. The assembly model is open so as to enable plug-and-play with various applications, such as analysis (FEM, tolerance, assembly), process planning, and virtual assembly (using VR techniques). With the advent of the Internet more and more products are designed and manufactured globally in a distributed and collaborative environment. The class structure defined in OAM can be used by designers to collaborate in such an environment. The proposed model includes both assembly as a concept and assembly as a data structure. For the latter it uses STEP. The OAM together with CPM can be used to capture the assembly evolution from the conceptual to the detailed design stages. It is expected that the proposed OAM will enhance the assembly information content in the STEP standard. A case study example is discussed to explain the Usecase analysis of the assembly model.

Product lifecycle management support: a challenge in supporting product design and manufacturing in a networked economy

In this paper, we provide an overview of the changing design and manufacturing landscape in the 21st century that has come about because of IT and the changing global conditions. Based on this overview and a review of the current state of IT for PLM support in the design and manufacturing sector, we identify the areas of need for standards. A review of areas covered by standards leads us to the development of an initial typology of standards and a potential path for bringing convergence of these standards in support of PLM. We make a case throughout the paper that given the nature of the task we need to aspire to create open standards with wide participation. We conclude by arguing that there is an important role to be played in this context by institutions such as NIST as a neutral party in the standards debates and implementations.

A web-based system for design artifact modeling

Abstract Engineering product development in todays industry is becoming increasingly knowledge intensive. The NIST Design Repository Project, at the National Institute of Standards and Technology, is working to develop infrastructural technologies to support the use of design repositories in industry. In contrast to traditional design databases, design repositories more actively support knowledge-based design, serving not only as archives, but as repositories of heterogeneous information that are designed to enable representation, capture, sharing, and reuse of corporate design knowledge. This paper presents a language that has been developed for the modeling of engineering design artifacts. The implementation of a prototype tool suite, which includes intelligent web-based interfaces that allow distributed users to create, edit and browse design repositories, is also described.