Analysis of Engineering Drawings: State of the Art and Challenges

Contribution à un ouvrage.In this paper, we analyze the state of the art in interpretation of engineering drawings, both from a methodological point of view and from the perspective of the applications. We try to emphasize where techniques are mature, where they need further maturing, and where we still have open challenges. Special attention is given to the progress in the last two years

Solid Modeling

To appear in the Encyclopedia of Electrical and Electronics Engineering, Ed. J. Webster, John Wiley & Sons, 1999.A solid model is a digital representation of the geometry of an existing or envisioned physical object. Solid models are used in many industries, from entertainment to health care. They play a major role in the discrete-part manufacturing industries, where precise models of parts and assemblies are created using solid modeling software or more general computer-aided design (CAD) systems. Solid modeling is an interdisciplinary field that involves a growing number of areas. Its objectives evolved from a deep understanding of the practices and requirements of the targeted application domains. Its formulation and rigor are based on mathematical foundations derived from general and algebraic topology, and from Euclidean, differential, and algebraic geometry. The computational aspects of solid modeling deal with efficient data structures and algorithms, and benefit from recent developments in the field of computational geometry. Efficient processing is essential, because the complexity of industrial models is growing faster than the performance of commercial workstations. Techniques for modeling and analyzing surfaces and for computing their intersections are important in solid modeling. This area of research, sometimes called computer aided geometric design, has strong ties with numerical analysis and differential geometry. Graphic user-interface (GUI) techniques also play a crucial role in solid modeling, since they determine the overall usability of the modeler and impace the user's productivity. There have always been strong symbiotic links and overlaps between the solid modeling community and the computer graphics community. Solid modeling interfaces are based on efficient three-dimensional (3D) graphics techniques, whereas research in 3D graphics focuses on fast or photo-realistic rendering of complex scenes, often composed of solid models, and on realistic or artistic animations of non-rigid objects. A similar symbiotic relation with computer vision is regaining popularity, as many research efforts in vision are model-based and attempt to extract 3D models from images or video sequences of existing parts or scenes. These efforts are particularly important for solid modeling, because the cost of manually designing solid models of existing objects or scenes far excees the other costs (hardware, software, maintenance, and training) associated with solid modeling. Finally, the growing complexity of solid models and the growing need for collaboration, reusability of design, and interoperability of software require expertise in distributed databases, constraint management systems, optimization techniques, object linking standards, and internet protocols. This report provides a brief overview of the solid modeling field, its fundamental technologies, and some important applications

A microworld model for multiagent computer-aided process planning.

This Thesis proposes and investigates a novel framework for the study of multiagent solutions for computer-aided process planning (CAPP) in manufacturing systems. The framework is based on a domain-specific microworld model of CAPP, called the CAPP World. The motivation comes from the current literature on multiagent systems (MAS) for CAPP, which emphasized the need for comparative studies that would identify the most suitable domain-specific multiagent solutions, and from the observation that a simple, manageable framework for such studies had not been developed. The proposed CAPP World is characterized by a product class, a model of a manufacturing cell, and appropriate adaptation and simplification of CAPP modeling concepts from the literature. These abstractions lead to a collection of specific actions that jointly construct a process plan in CAPP World. The analysis shows that the model meets its design objectives of being: simple integral in the sense of including the main aspects of CAPP representative of properties and difficulties in real-world CAPP and suitable for formulation and investigation of MAS solutions for CAPP. The suitability of CAPP World for domain-specific MAS studies is demonstrated through construction of concrete scenarios addressing topics such as: agent encapsulation, cooperation and coordination among team members, cooperative iterative improvements of process plan, improving the efficiency of process planning through caching of design solutions, team composition, and communication mechanisms. The Thesis also identifies some topics for future research. --P.[i]The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b164402