Ram Sriram - Academia.edu (original) (raw)

Papers by Ram Sriram

Engineering with Computers, 2007

The Core Product Model (CPM) was developed at NIST as a high level abstraction for representing p... more The Core Product Model (CPM) was developed at NIST as a high level abstraction for representing product related information, to support data exchange, in a distributive and a collaborative environment. In this paper, we extend the CPM to components with continuously varying material properties. Such components are becoming increasing important and popular due to progress in design, analysis and manufacturing techniques. The key enabling concept for modeling continuously varying material properties is that of distance fields associated with a set of material features, where values and rates of material properties are specified. Material fields, representing distribution of material properties within a component, are usually expressed as functions of distances to material features, and are controlled with a variety of differential, integral or algebraic constraints. Our formulation is independent of any particular platform or representation, and applies to most proposed techniques for representing continuously varying material properties. The proposed model is described using system independent Unified Modeling Language (UML) and is illustrated through a number of specific examples.

Volume 4: Design for Manufacturing Conference, 1997

This paper introduces an information modeling framework to support representation of design artif... more This paper introduces an information modeling framework to support representation of design artifacts for design databases and repositories. While most artifact representations consist primarily of geometric information, the object-oriented design modeling language developed through this work enables representation of not only form, but also function and behavior. This research has resulted in the implementation of a design artifact database as well as an information browser that provides the user interface to information contained therein. The implementation is demonstrated using the representation of a power drill as an example.

A major challenge of any product engineering project is to support the creation, exchange, manage... more A major challenge of any product engineering project is to support the creation, exchange, management and archival of information about product, process, people and services across the networked and extended enterprise covering the entire product lifecycle spectrum. An information support system for Product Lifecycle Management (PLM) requires a move from product data exchange to product information and knowledge exchange across different disciplines and domains. PLM support systems will need to have both syntactic and semantic interoperability of computer systems and people through well defined standards. We begin this paper with a model of communication between two agents and then extend this model to describe the information flows in PLM so as to serve as the basis for understanding the role of standards for PLM support systems. Support of PLM requires a set of complementary and interoperable standards that cover the various aspects of PLM. We identify an initial typology of standards relevant to PLM support. The typology primarily addresses the hierarchy of existing and evolving standards and their usage. The typology identifies a suite of complementary standards supporting the exchange of product, process, operations and supply chain information. Given the nature of the task of developing and deploying a set of standards for PLM support systems, we argue that open standards with wide participation are the key to their realization.

The Standard for the Exchange of Product model data (STEP) [1] contains product information mainl... more The Standard for the Exchange of Product model data (STEP) [1] contains product information mainly related to geometry. The modeling language used to develop this standard, EXPRESS, does not have logical formalism that will enable rigorous semantics. In this paper we present an OWL-DL (Web Ontology Language-Description Logic) [2] version of STEP (OntoSTEP) that will allow logic reasoning and inference mechanisms and thus enhancing semantic interoperability. The development of OntoSTEP requires the conversion of EXPRESS schema to OWL-DL, and the classification of EXPRESS instances to OWL individuals. Currently we have considered AP203 [3]-the most widely used Application Protocol (AP) for the exchange of Computer-Aided Design (CAD) files-and STEP Part 21 [4] CAD files-CAD files conformant to the data exchange format defined in Part 21-for schema level conversion and instance level classification respectively. We will describe a web application to demonstrate OntoSTEP. We are currently extending OntoSTEP to include information such as function, behavior, and assembly requirements.

Volume 4a: ASME/IEEE Conference on Mechatronic and Embedded Systems and Applications, 2005

In this paper, we develop distributed design models and framework for collaborative embedded syst... more In this paper, we develop distributed design models and framework for collaborative embedded system design. Based on the component-based approach, a unified design-with-modules scheme is proposed to model the embedded system design process and a web-based distributed module modeling and evaluation (WebDMME) framework is developed as a collaborative cyber-infrastructure to support distributed network-centric embedded system design. The framework intends to link distributed, heterogeneous hardware/software (HW/SW) design models and tools and assist designers in evaluating design alternatives, visualizing trade-offs, finding optimal solutions, and making decisions on the web. It also enables designers to build integrated design models using both the local and distributed resources (e.g., local and distributed HW/SW modules) and to cooperate by exchanging services. The client (browser) / knowledge server architecture allows embedded system design models to be published and connected over the web to form an integrated intelligent models/modules network. Finally, as an illustration, a model for modular microrobotic systems design is developed.

Journal of Computing and Information Science in Engineering, 2000

Information technology has played an increasingly important role in engineering product developme... more Information technology has played an increasingly important role in engineering product development. Its influence over the past decade has been accelerating and its impact in the coming decade will undoubtedly be immense. This paper surveys several research areas relating to knowledge representation, capture and retrieval, which will have a growing influence on product development. Each of these areas could, on its own, provide sufficient material for an entire survey paper. Unlike traditional survey papers, this paper does not attempt to provide a comprehensive review of a field of research from its inception to the present. Rather, this paper aims to touch on a representative selection of recent developments in these influential technical areas. The paper provides perspectives into the kinds of technologies that are emerging from rapidly expanding fields of research, and discusses challenges that must be overcome to enable transition of these technologies into industry practice t...

Advances in Soft Computing, 1999

Modern engineering industry is relying more and more on the use of knowledge in product developme... more Modern engineering industry is relying more and more on the use of knowledge in product development. This paper advocates design repositories as a natural progression from traditional design databases to systems that are created to more actively support knowledge-based design. In contrast to traditional design databases, design repositories serve 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 describes the NIST Design Repository Project, an ongoing project within the Engineering Design Technologies Group at the National Institute of Standards and Technology (NIST). The project objectives are to develop a computational framework for the creation of design repositories, and a proof-of-concept prototype to demonstrate their benefits. A number of research issues associated with the envisioned role of design repositories in industry are addressed. The current state of the project and its implementation are presented.

Journal of Computing and Information Science in Engineering, 2006

The early part of this millennium has witnessed the emergence of an Internet-based engineering ma... more The early part of this millennium has witnessed the emergence of an Internet-based engineering marketplace. Here, engineers, designers, and manufacturers from small and large companies can collaborate electronically in various product development and marketing activities. These capabilities are being enhanced by a new manufacturing software environment comprised of a network of cooperating engineering applications. These applications include multi-media tools and techniques that facilitate collaboration between geographically distributed applications and virtual reality tools that enable visualization and simulation in a synthetic environment. In this paper, we provide an overview of a network-centric design and manufacturing environment, followed by discussions on the role information exchange standards play in the seamless interoperation of these tools and dynamic composition of engineering applications and services.

2010 IEEE International Conference on Automation Science and Engineering, 2010

Supporting different stakeholder viewpoints across the product's entire lifecycle requires semant... more Supporting different stakeholder viewpoints across the product's entire lifecycle requires semantic richness for representing product related information. This paper proposes a multi-layered product-modeling framework that enables stakeholders to define their product-specific models and relate product-specific models to physical or simulated instances. The framework is defined within the Model-driven Architecture and adapted to the multi-layer approach of the architecture. The data layer represents real world products, the model layer includes models of those products, and the meta-model layer defines the product modeling language. The semantic-based product modeling language described in this paper is specialized from a web ontology language enabling product designers to express the semantics of their product models explicitly and logically in an engineering-friendly way. The interactions between these three layers are described to illustrate how each layer in the framework is used in a product engineering context. FFICIENT collaboration is essential when products are designed by temporally and spatially separated engineers. Collaborative environments enable product designers to interact and reach agreement by sharing design knowledge and product information [1], [2]. Ontology can play a role in the environments as a shared product information model because ontology is a formal and explicit specification of a shared conceptualization [3]. The collaborative environment needs the support of a generic product modeling language that: (1) can be readily specialized for the products at hand; (2) can provide information to all stakeholders throughout the product lifecycle; and (3) provides explicit, logical semantics of the concepts and relationships involved, without requiring that the stakeholders be versed in ontological thinking. Ontological multi-layered product modeling frameworks provide the above capabilities [4]. Figure 1 shows a high level Manuscript received March 31, 2010.

Journal of Computing and Information Science in Engineering, 2005

The paper discusses the evolution of product information exchange from point-to-point exchange of... more The paper discusses the evolution of product information exchange from point-to-point exchange of geometry between Computer-aided Design (CAD) tools through today's suite of tools and processes of Computer-aided Product Development (CAPD) to the future fully integrated Computer-aided Product Realization (CAPR) process. The categories of processes and the layers of information exchange are reviewed. The current practice in product information exchange, the relevant information exchange standards, and near-future plans for improvements are presented. The major recent demands on more comprehensive product information exchange are discussed in terms of the exchange of non-geometric information and support of feature-based design, knowledge-based engineering and management of product variety. Two conceptual frameworks for the support of CAPD and CAPR, representative of current research, are briefly sketched. Finally, a conceptual model of product information exchange is presented so as to define the range of implementation and standardization paths that may be taken in the future.

Designers and engineers use various engineering authoring tools, such as CAD, CAE, and PDM, to ge... more Designers and engineers use various engineering authoring tools, such as CAD, CAE, and PDM, to generate information objects (engineering objects). On the business side, enterprise level business process modelers use various business authoring tools, such as ERP, CRM, and LCA, to generate information objects (business objects). These information objects, both engineering and business, are represented using information standards. These standards are used to exchange information about engineering and business systems for enterprise level interoperability. One of the main problems of designers, engineers and process modelers is the selection of appropriate standards for interoperability. To ensure enterprise level interoperability, it is absolutely critical that information standards are compared and harmonized as there are overlapping and dissimilar standards available. In this paper, we will sketch a method towards comparing and harmonizing standards based on: 1) informal approach, 2) typology of standards, 3) use-case scenarios, and 4) ontologies. The method is explained using some engineering and business standards. I.

Journal of Computing and Information Science in Engineering, 2008

The support of PLM throughout the product life, from the product's conceptualization to its dispo... more The support of PLM throughout the product life, from the product's conceptualization to its disposal, requires reliable, complete and efficient data models. The Core Product Model (CPM), initially developed at NIST for a number of in-house research projects, has been extended so as to support the full range of PLM information. CPM gives equal status to three aspects of a product or artifact: its function, form and behavior. Thus, CPM can support purely functional reasoning about a product in the conceptual stages of design as well as the recording and modeling of its behavior in the post-design stage. CPM is a generic, abstract model with generic semantics. It is defined as a UML class diagram.. Three levels of CPM models, denoted as the conceptual, intermediate, and implementation models, are described. Extensions of CPM are briefly presented and a short illustrative example is given.

Volume 3: 25th Computers and Information in Engineering Conference, Parts A and B, 2005

Product Lifecycle Management (PLM) is a concept that takes into account that the development of a... more Product Lifecycle Management (PLM) is a concept that takes into account that the development of a product is influenced by knowledge from various stakeholders throughout its lifecycle. Computing environments in the PLM framework are expected to have several independent information resources. This requires a meaningful formal representation of product data semantics throughout the product’s lifecycle. This paper presents an ontological approach to formalize product semantics into a Product Semantic Representation Language (PSRL). Building blocks to develop the explicit, extensible and comprehensive PSRL are described. The PSRL is open and based on standard W3L OWL constructs. The extensibility is demonstrated by considering an example product. The representation and the method of its development is expected to support several applications in the context of PLM. The use of OWL will enable the provision of the application software and information resources as Web services in the contex...

International Journal of Product Lifecycle Management, 2005

In this paper, we provide an overview of the changing design and manufacturing landscape in the 2... more In this paper, we provide an overview of the changing design and manufacturing landscape in the 21 st 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.

IEEE Transactions on Automation Science and Engineering, 2005

An increasing trend toward product development in a collaborative environment has resulted in the... more 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. Index Terms-CAD/CAM integration, ontologies, product data exchange, semantic interoperability. I. INTRODUCTION M ODERN product development is performed by crossfunctional teams distributed geographically and temporally. Designers do not exchange mere geometric information

IEEE Transactions on Automation Science and Engineering, 2012

Supporting different stakeholder viewpoints across the product lifecycle requires semantic richne... more Supporting different stakeholder viewpoints across the product lifecycle requires semantic richness to represent product-related information and enable multiview engineering simulations. This paper proposes a multilevel product modeling framework enabling stakeholders to define product models and relate them to physical or simulated instances. The framework is defined within the Model-Driven Architecture using the multilevel (data, model, metamodel) approach. The data level represents real-world products, the model level describes models (product models) of real-world products, and the metamodel level describes models of the product models. The metamodel defined in this paper is specialized from a web ontology language enabling product designers to express the semantics of product models in an engineering-friendly way. The interactions between these three levels are described to show how each level in the framework is used in a product engineering context. A product design scenario and user interface for the product metamodel is provided for further understanding of the framework. Note to Practitioners-The views of stakeholders in a product lifecycle may be different according to their concerns. However, they develop product models and data for a same product. The product models and data should be managed in a single framework to validate consistency of product information. The framework proposed in this paper enables stakeholders to define their product models and relate them to physical or simulated instances. A generic metamodel is also proposed to guide engineers in building their product models using engineer-friendly terms. A product design scenario and user interface prototype was implemented for further understanding of the framework and the metamodel. If the prototype is integrated with a Computer-Aided Design (CAD) system, it can be a powerful mechanism for semantically annotating CAD models.

IEEE Intelligent Systems, 2000

Design Studies, 2000

Engineering product development i n t o d a y's industry is becoming increasingly knowledge inten... more Engineering product development i n t o d a y's industry is becoming increasingly knowledge intensive. The NIST Design Repository Project, at the National Institute of Standards and Technology, i s w orking 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 w eb-based interfaces that allow distributed users to create, edit and browse design repositories, is also presented.