Cumincad : CUMINCAD Papers : Search Results

CumInCAD is a Cumulative Index about publications in Computer Aided Architectural Design
supported by the sibling associations ACADIA, CAADRIA, eCAADe, SIGraDi, ASCAAD and CAAD futures

PDF papers
References

Hits 1 to 20 of 153

Reformat results as: short short into frame detailed detailed into frame

_id	88cb
authors	Gero, John S. and Oksala, Tarkko (editors)
year	1988
title	Knowledge-Based Systems in Architecture
source	TIPS'88 - Knowledge Based Design in Architecture, Acta Polytechnica Scandinavica (1988 : Helsinki, Finland). 143 p. 1989
summary	The technology of knowledge-based systems can be found in texts on artificial intelligence. There is very little published so far on knowledge-based systems in architecture. To this end an international conference -- TIPS' 88: Knowledge-Based Design in Architecture -- was organized for August 1988 in Finland. Thirteen papers from that conference have been selected and edited for this monograph. They are grouped under five parts: Introduction; Schemas and Models; Processes and Knowledge; Modeling Buildings; and Creativity and Knowledge-Based Systems
keywords	knowledge base, architecture, representation, expert systems,building, creativity
series	CADline
email
last changed	2003/06/02 13:58

_id	cc50
authors	Gossard, D.C., Zuffante, R.P. and Sakurai, H.
year	1988
title	Representing Dimensions, Tolerances, and Features in MCAE Systems
source	IEEE Computer Graphics and Applications. March, 1988. vol. 8: pp. 51-59 : ill. includes bibliography
summary	Presented is a method for explicitly representing dimensions, tolerances, and geometric features in solid models. The method combines CSG and boundary representations in a graph structure called an object graph. Dimensions are represented by a relative position operator. The method can automatically translate changes in dimensional values into corresponding changes in geometry and topology. The representation provides an important foundation for higher level application programs to automate the redesign of assemblies and to automate tolerance analysis and synthesis. A prototype interactive polyhedral modeler based on this representation was implemented
keywords	CAE, B-rep, representation, CAD, CAM, features, dimensioning, tolerances, graphs, topology, geometric modeling, assemblies
series	CADline
last changed	2003/06/02 14:42

_id	7812
authors	Straber, W. and Seidel, H.-P. (eds.)
year	1989
title	Theory and Practice of Geometric Modeling
source	Springer-Verlag
summary	This book originates from the lectures given at the international conference "Theory and Practice of Geometric Modeling", Blaubeuren, FRG, October 3-7, 1988, that brought together leading experts from universities, system developers, and system users, to discuss new concepts and future trends in geometric modeling. The book covers a variety of topics on an advanced level and is organized as follows. Part A contains new algorithms and techniques for modeling objects that are bounded by free form surfaces. Part B focuses on surface/surface intersections, new types of blending surfaces and speed ups for ray tracing. Part C contains some new geometric tools. Part D discusses different representation schemes in solid modeling, conversions between these different schemes, and some applications. Part E covers some issues of product modeling, automatic tolerancing, high level specification of solid models (constraints, features) and the need for better user interfaces.
series	other
last changed	2003/04/23 15:14

_id	abaf
authors	Veenstra, Jack and Ahuja, Narendra
year	1988
title	Line Drawings of Octree- Represented Objects
source	ACM Transactions on Graphicsò January, 1988. vol. 7: pp. 61-75 : ill. includes bibliography.
summary	The octree structure represents the space occupied by an object as a juxtaposition of cubes. The octree structure is highly sensitive to object location and orientation, and the three-dimensional shape of the represented object is obscured. It is helpful to be able to see the actual object represented by an octree, especially for visual performance evaluation of octree algorithms. This paper presents a display algorithm that helps visualize the three-dimensional space represented by the octree. Given an octree, the algorithm produces a line drawing of the object represented by the octree, using parallel projection, from any specified viewpoint with hidden lines removed. Example of some line drawing produced by the algorithm are given. The complexity of the algorithm is also discussed
keywords	hidden lines, drawings, solid modeling, representation, octree, display, computer graphics
series	CADline
last changed	2003/06/02 13:58

_id	6ca4
authors	Woodbury, Robert F. and Oppenheim, Irving R.
year	1988
title	An Approach to Geometric Reasoning
source	20 p. : ill. Pittsburgh, PA: Engineering Design Research Center, CMU, June, 1988. EDRC-48-06-88. includes bibliography
summary	An approach to the integration of geometric information in knowledge based CAD systems is described as an architecture for geometric reasoning. The general requirements for this integration arise from the need for rich geometry representations in engineering domains and the conflicting demands of current geometric modelling and knowledge based systems. Four concepts are used as a basis: (1) Classes of spatial sets, which act by inheritance as a means for incremental definition by specialization; (2) features, which denote evaluated portions of a geometric model; (3) abstractions, which provide partial representations of geometric objects; and (4) constraints through which spatial relationships are expressed. These four concepts combine in a synergistic manner to define the complete architecture. A prototype implementation of the architecture, built using object oriented programming techniques and a boundary based solid modeler, has been achieved and demonstrated. In this paper each of the concepts and their integration into a whole are described
keywords	geometric modeling, knowledge base, systems, constraints, design, knowledge, architecture, methods, reasoning, integration
series	CADline
email
last changed	2003/06/02 10:24

_id	c57b
authors	Bier, Eric A.
year	1988
title	Snap-Dragging. Interactive Geometric design in Two and Three Dimensions
source	University of California, Berkeley
summary	Graphic artists, mechanical designers, architects, animators, authors of technical papers and others create geometric designs (illustrations and solid models) as a major part of their daily efforts. Some part of this shape construction must be done with precision. For instance, certain line segments should be horizontal, parallel or congruent. In recent years, interactive computer programs have been used to speed up the production of precise geometric designs. These programs take advantage of high-speed graphics, equation solving, and computer input peripherals to reduce the time needed to describe point positions to the machine. Previous techniques include rounding the cursor to points on a rectangular grid, solving networks of constraints, and supporting step-by-step drafting-style constructions. Snap-dragging is a modification of the drafting approach that takes advantage of powerful workstations to reduce the time needed to make precise illustrations. Using a single gravity mapping, a cursor can be snapped to either points, lines or surface. The gravity algorithm achieves good performance by computing intersection points on the fly. To aid precise construction, a set of lines, circles, planes, and spheres, called alignment objects, are constructed by the system at a set of slopes, angles, and distances specified by the user. These alignments objects are constructed at each vertex or edge that the user has declared to be hot (of interest). Vertices and edges can also be made hot by the system through the action of an automatic hotness rule. When snap-dragging is used, shapes can often be constructed using a few more keystrokes than would be needed to sketch them freehand. Objects can be edited at arbitrary orientations and sizes. The number of primitive operations is small, making it possible to provide keyboard combinations for quickly activating most of these operations. The user interface works nearly identically in two or three dimensions. In three dimensions, snap-dragging works with a two-dimensional pointing device in a single perspective view.
series	thesis:PhD
email
last changed	2003/02/12 22:37

_id	cf08
authors	Blaha, Michael R., Premerlani, William J. and Rumbaugh, James E.
year	1988
title	Relational Database Design Using An Object- Oriented Methodology
source	communications of the ACM. April, 1988. vol. 31: pp. 414-427 : ill. includes a short bibliography
summary	Object-oriented concepts provide a useful abstraction for relational database design. In this article the authors present a design technique that has been used for several projects at General Electric. The methodology is intuitive, expressive, and extensible. The new approach to relational database design is based on the work of Loomis, Sha, and Rumbaugh
keywords	relational database, design, methods, objects, modeling, representation
series	CADline
last changed	2003/06/02 13:58

_id	0ee6
authors	Boyle, R. and Thomas, R.
year	1988
title	Computer Vision: A First Course
source	Blackwell Scientific Publications
summary	Computer vision is a new discipline recently developed from image processing, which is able to take raw images, and, after suitable processing, derive information from them automatically. Computer vision applications are legion in the areas of automated manufacture and robotics, where it may be addressed to such problems as resolving motion in images, and 3-D analysis. This book is a much-needed introduction to the subject for senior undergraduates and graduates. It covers the necessary mathematical techniques at a level suitable for the mathematical literate who has not encountered any image processing before, and proceeds to an examination of some pure vision applications. There is a discussion of human perception and how it relates to machine perception, and there are examples throughout the text, with exercises at the end of each chapter. Table of Contents Perception A pattern recognition system Image acquisition and modelling Low level processing Segmentation A PCB example Line labelling Towards three dimensions Knowledge representation Rule based systemsl Epilogue Appendices.
series	other
last changed	2003/04/23 15:14

_id	6f1b
authors	De Floriani, Leila and Falcidieno, Bianca
year	1988
title	A Hierarchical Boundary Model for Solid Object Representation
source	ACM Transactions on Graphics. January, 1988. vol. 7: pp. 42-60 : ill. includes bibliography
summary	A new hierarchical model for solid object representation is described. This model, called a Hierarchical Face Adjacency Hypergraph (HFAH), is based on a relational description of the object boundary, called a Face Adjacency Hypergraph (FAH), which considers faces as the primary topological entities defining the object boundary. The HFAH consists of a hierarchy of FAHs describing the decomposition of the boundary of an object into form features. In this paper the HFAH is described together with its internal encoding structure. Two basic transformations, called refinement and abstraction, are defined on the hierarchical model; these allow effective and efficient modifications of the hierarchical boundary model
keywords	representation, computational geometry, solid modeling, algorithms, design, data structures, graphs, features, B-rep
series	CADline
last changed	2003/06/02 13:58

_id	f65d
authors	Kalisperis, L.N.
year	1988
title	A Conceptual Framework for Computing in Architectural Design
source	Pennsylvania State University
summary	A brief historical overview of architectural design reveals that there has been a slow development in the conceptualization of the scope of architectural design. Advancing our understanding of the architectural design process reveals new directions for computing in architectural design. This study proposes a conceptual framework for an integrated computing environment. Design disciplines have embarked on a rigorous search for theoretical perspectives and methods that encompass a comprehensive view of architecture. Architectural design has been seen as a sequential process similar to that of industrial design. Attempts to formalize this process based on industrial design methods solved only a fraction of the overall integration problem. The resultant models are inadequate to deal with the complexity of architectural design. Emerging social problem-solving paradigms seek to construct a cognitive psychology of problem solving and have a direct relevance to architectural design. These problem-solving activities include structured, semi-structured, and ill-defined problems, which are included to varying degrees in each problem situation across a continuum of difficulty. Problem solving in architectural design involves the determination of certain objectives and also whether or not it is possible to accomplish them. Developments in computing in architecture have paralleled developments in architectural methodologies. The application of computing in architectural design has predominantly focused only on sequential process, optimum solutions, and quantifiable tasks of the design process. Qualitative, generative, tasks of architectural design were dealt with through the introduction of paradigms from linguistics and knowledge-based systems borrowed from engineering applications. Although the application of such paradigms resulted in some success, this reductionist approach to computing in architecture fragmented its integration into the design process. What is required, therefore, is a unified approach to computing in architecture based on a holistic view of the architectural design process. The model proposed in this study provides such a conceptual framework. This model shifts the focus from product to process and views the design problem as a goal-oriented problem-solving activity that allows a design team to identify strategies and methodologies in the quest for design solutions.
series	thesis:PhD
email
last changed	2003/02/12 22:37

_id	b0f7
authors	Martens, Bob
year	1992
title	A FINISHING TOUCH TO THE FULL-SCALE LABORATORY AT THE UNIVERSITY OF TECHNOLOGY IN VIENNA
source	Proceedings of the 4rd European Full-Scale Modelling Conference / Lausanne (Switzerland) 9-12 September 1992, Part A, pp. 7-14
summary	The development planning of the full-scale laboratory at the Vienna University of Technology was already presented to the third E.F.A. Conference in Lund (1990). Exchange of experience has greatly encouraged us to take all measures necessary for an immediate provisional operation. Working experience was of considerable significance regarding reconstruction work having repeatedly been postponed ever since 1988. This paper deals with the Vienna full-scale laboratory in its ultimate form and all the equipment designed therefore. Summarizingly, the further measures for operation are being considered.
keywords	Full-scale Modeling, Model Simulation, Real Environments
series	other
type	normal paper
email
more	http://info.tuwien.ac.at/efa
last changed	2004/05/04 15:30

_id	cb88
authors	Novak, Marcos J.
year	1988
title	Computational Composition in Architecture
source	Computing in Design Education [ACADIA Conference Proceedings] Ann Arbor (Michigan / USA) 28-30 October 1988, pp. 5-30
doi	https://doi.org/10.52842/conf.acadia.1988.005
summary	The impact of computers on architectural design, manifested through the creation of architectural designs that equal or surpass in quality and sophistication architecture generated using traditional means, has yet to be demonstrated. Computer-aided design is conspicuously absent from theoretical discussions of architectural design per se, and there exist no major built or published buildings that have been designed using the computer in a true design capacity. Most prominent architects continue to ignore computer-aided design. This paper argues that the issues of architectural theory and composition must be addressed directly by the computer-aided design field, and that until this occurs computer-aided architectural design will necessarily be peripheral to architecture because it does not address the central problems of architecture as an expressive medium. To this end, it proposes a shift to the paradigm of computational composition, and discusses recent work in this direction. The paper is divided into four parts. Part I identifies fundamental theoretical problems, contrasts the application of computation to architecture and to music, and draws upon several different areas for insight into the nature of making; Part II reviews particular architectural implications of these considerations, introduces the concept of computational composition in architecture, and presents a brief overview of important precedents; Part III proposes new goals for computer-aided architectural design and presents a framework for computational composition; finally, Part IV presents recent work directly related to the ideas presented in the previous parts and leads to the Conclusion. The appendices contain a pseudo-Prolog expression of Alvar Aalto's architectural language and notes on features of the PADL-2 solid modeler that are architecturally interesting.
series	ACADIA
email
last changed	2022/06/07 08:00

_id	47e7
authors	Segal, Mark and Sequin, Carlo H.
year	1988
title	PARTITIONING POLYHEDRAL OBJECTS INTO NONINTERSECTING PARTS
source	IEEE Computer Graphics and Applications. January, 1988. vol. 8: pp. 53-67 : ill. some col. includes bibliography
summary	The article describes an algorithm for partitioning intersecting polyhedrons into disjoint pieces and, more generally, removing intersections from sets of planar polygons embedded in three space. Polygons, or faces, need not be convex and may contain multiple holes. Intersections are removed by considering pairs of faces and slicing the faces apart along their regions of intersection. To reduce the number of face pairs examined, bounding boxes around groups of faces are checked for overlap. The intersection algorithm also computes set theoretic operations on polyhedrons. Information gathered during face cutting is used to determine which portions of the original boundaries may be present in the result of an intersection, a union, or a difference of solids. The method includes provisions to detect, and in some cases overcome, the effects of numerical inaccuracy on the topological decisions that the algorithm must make. The regions in which ambiguous results are possible are flagged so that the user can take appropriate action.
keywords	geometric modeling, computer graphics, objects, programming, hidden surfaces, hidden lines, business, practice, systems, user interface, UNIX
series	CADline
type	normal paper
last changed	2005/10/05 07:39

_id	avocaad_2001_19
id	avocaad_2001_19
authors	Shen-Kai Tang, Yu-Tung Liu, Yu-Sheng Chung, Chi-Seng Chung
year	2001
title	The visual harmony between new and old materials in the restoration of historical architecture: A study of computer simulation
source	AVOCAAD - ADDED VALUE OF COMPUTER AIDED ARCHITECTURAL DESIGN, Nys Koenraad, Provoost Tom, Verbeke Johan, Verleye Johan (Eds.), (2001) Hogeschool voor Wetenschap en Kunst - Departement Architectuur Sint-Lucas, Campus Brussel, ISBN 80-76101-05-1
summary	In the research of historical architecture restoration, scholars respectively focus on the field of architectural context and architectural archeology (Shi, 1988, 1990, 1991, 1992, 1995; Fu, 1995, 1997; Chiu, 2000) or on architecture construction and the procedure of restoration (Shi, 1988, 1989; Chiu, 1990). How to choose materials and cope with their durability becomes an important issue in the restoration of historical architecture (Dasser, 1990; Wang, 1998).In the related research of the usage and durability of materials, some scholars deem that, instead of continuing the traditional ways that last for hundreds of years (that is to replace new materials with old ones), it might be better to keep the original materials (Dasser, 1990). However, unavoidably, some of the originals are much worn. Thus we have to first establish the standard of eliminating components, and secondly to replace identical or similar materials with the old components (Lee, 1990). After accomplishing the restoration, we often unexpectedly find out that the renewed historical building is too new that the sense of history is eliminated (Dasser, 1990; Fu, 1997). Actually this is the important factor that determines the accomplishment of restoration. In the past, some scholars find out that the contrast and conflict between new and old materials are contributed to the different time of manufacture and different coating, such as antiseptic, pattern, etc., which result in the discrepancy of the sense of visual perception (Lee, 1990; Fu, 1997; Dasser, 1990).In recent years, a number of researches and practice of computer technology have been done in the field of architectural design. We are able to proceed design communication more exactly by the application of some systematic softwares, such as image processing, computer graphic, computer modeling/rendering, animation, multimedia, virtual reality and so on (Lawson, 1995; Liu, 1996). The application of computer technology to the research of the preservation of historical architecture is comparatively late. Continually some researchers explore the procedure of restoration by computer simulation technology (Potier, 2000), or establish digital database of the investigation of historical architecture (Sasada, 2000; Wang, 1998). How to choose materials by the technology of computer simulation influences the sense of visual perception. Liu (2000) has a more complete result on visual impact analysis and assessment (VIAA) about the research of urban design projection. The main subjects of this research paper focuses on whether the technology of computer simulation can extenuate the conflict between new and old materials that imposed on visual perception.The objective of this paper is to propose a standard method of visual harmony effects for materials in historical architecture (taking the Gigi Train Station destroyed by the earthquake in last September as the operating example).There are five steps in this research: 1.Categorize the materials of historical architecture and establish the information in digital database. 2.Get new materials of historical architecture and establish the information in digital database. 3.According to the mixing amount of new and old materials, determinate their proportion of the building; mixing new and old materials in a certain way. 4.Assign the mixed materials to the computer model and proceed the simulation of lighting. 5.Make experts and the citizens to evaluate the accomplished computer model in order to propose the expected standard method.According to the experiment mentioned above, we first address a procedure of material simulation of the historical architecture restoration and then offer some suggestions of how to mix new and old materials.By this procedure of simulation, we offer a better view to control the restoration of historical architecture. And, the discrepancy and discordance by new and old materials can be released. Moreover, we thus avoid to reconstructing ¡§too new¡¨ historical architecture.
series	AVOCAAD
email
last changed	2005/09/09 10:48

_id	avocaad_2001_20
id	avocaad_2001_20
authors	Shen-Kai Tang
year	2001
title	Toward a procedure of computer simulation in the restoration of historical architecture
source	AVOCAAD - ADDED VALUE OF COMPUTER AIDED ARCHITECTURAL DESIGN, Nys Koenraad, Provoost Tom, Verbeke Johan, Verleye Johan (Eds.), (2001) Hogeschool voor Wetenschap en Kunst - Departement Architectuur Sint-Lucas, Campus Brussel, ISBN 80-76101-05-1
summary	In the field of architectural design, “visualization¨ generally refers to some media, communicating and representing the idea of designers, such as ordinary drafts, maps, perspectives, photos and physical models, etc. (Rahman, 1992; Susan, 2000). The main reason why we adopt visualization is that it enables us to understand clearly and to control complicated procedures (Gombrich, 1990). Secondly, the way we get design knowledge is more from the published visualized images and less from personal experiences (Evans, 1989). Thus the importance of the representation of visualization is manifested.Due to the developments of computer technology in recent years, various computer aided design system are invented and used in a great amount, such as image processing, computer graphic, computer modeling/rendering, animation, multimedia, virtual reality and collaboration, etc. (Lawson, 1995; Liu, 1996). The conventional media are greatly replaced by computer media, and the visualization is further brought into the computerized stage. The procedure of visual impact analysis and assessment (VIAA), addressed by Rahman (1992), is renewed and amended for the intervention of computer (Liu, 2000). Based on the procedures above, a great amount of applied researches are proceeded. Therefore it is evident that the computer visualization is helpful to the discussion and evaluation during the design process (Hall, 1988, 1990, 1992, 1995, 1996, 1997, 1998; Liu, 1997; Sasada, 1986, 1988, 1990, 1993, 1997, 1998). In addition to the process of architectural design, the computer visualization is also applied to the subject of construction, which is repeatedly amended and corrected by the images of computer simulation (Liu, 2000). Potier (2000) probes into the contextual research and restoration of historical architecture by the technology of computer simulation before the practical restoration is constructed. In this way he established a communicative mode among archeologists, architects via computer media.In the research of restoration and preservation of historical architecture in Taiwan, many scholars have been devoted into the studies of historical contextual criticism (Shi, 1988, 1990, 1991, 1992, 1995; Fu, 1995, 1997; Chiu, 2000). Clues that accompany the historical contextual criticism (such as oral information, writings, photographs, pictures, etc.) help to explore the construction and the procedure of restoration (Hung, 1995), and serve as an aid to the studies of the usage and durability of the materials in the restoration of historical architecture (Dasser, 1990; Wang, 1998). Many clues are lost, because historical architecture is often age-old (Hung, 1995). Under the circumstance, restoration of historical architecture can only be proceeded by restricted pictures, written data and oral information (Shi, 1989). Therefore, computer simulation is employed by scholars to simulate the condition of historical architecture with restricted information after restoration (Potier, 2000). Yet this is only the early stage of computer-aid restoration. The focus of the paper aims at exploring that whether visual simulation of computer can help to investigate the practice of restoration and the estimation and evaluation after restoration.By exploring the restoration of historical architecture (taking the Gigi Train Station destroyed by the earthquake in last September as the operating example), this study aims to establish a complete work on computer visualization, including the concept of restoration, the practice of restoration, and the estimation and evaluation of restoration.This research is to simulate the process of restoration by computer simulation based on visualized media (restricted pictures, restricted written data and restricted oral information) and the specialized experience of historical architects (Potier, 2000). During the process of practicing, communicates with craftsmen repeatedly with some simulated alternatives, and makes the result as the foundation of evaluating and adjusting the simulating process and outcome. In this way we address a suitable and complete process of computer visualization for historical architecture.The significance of this paper is that we are able to control every detail more exactly, and then prevent possible problems during the process of restoration of historical architecture.
series	AVOCAAD
email
last changed	2005/09/09 10:48

_id	fc80
authors	Ubbelohde, S. and Humann, C.
year	1998
title	Comparative Evaluation of Four Daylighting Software Programs
source	1998 ACEEE Summer Study on Energy Efficiency in Buildings Proceedings. American Council for an Energy-Efficient Economy
summary	By the mid-1980's, a number of software packages were under development to predict daylighting performance in buildings, in particular illumination levels in daylighted spaces. An evaluation in 1988 by Ubbelohde et al. demonstrated that none of the software then available was capable of predicting the simplest of real daylighting designs. In the last ten years computer capabilities have evolved rapidly and we have four major packages widely available in the United States. This paper presents a comparative evaluation from the perspective of building and daylighting design practice. A contemporary building completed in 1993 was used as a base case for evaluation. We present the results from field measurements, software predictions and physical modeling as a basis for discussing the capabilities of the software packages in architectural design practice. We found the current software packages far more powerful and nuanced in their ability to predict daylight than previously. Some can accurately predict quantitative daylight performance under varying sky conditions and produce handsome and accurate visualizations of the space. The programs differ significantly, however, in their ease of use, modeling basis and the emphasis between quantitative predictions and visualization in the output.
series	other
last changed	2003/04/23 15:50

_id	0051
authors	Wastell, D.G. and White, P.
year	1993
title	Using Process Technology to Support Cooperative work: Prospects and Design Issues
source	CSCW in Practice: An Introduction and Case Studies. pp. 105-126. Edited by Dan Diaper and Colston Sanger, London: Springer-Veriag
summary	CSCW is a diverse and eclectic field. The theme which unifies CSCW is the question of group coordination, how it is achieved as a social phenomenon and how it may be actively assisted by computer-based support. The nature of these social processes are variously discussed in many of this book's other chapters. The issue of what is "true" CSCW and what is not is a contentious academic issue. Support for non-routine "professional" work such as collaborative writing would be widely accepted as a paradigm of CSCW (see, in particular, Sharples, Chapter 4; Gilbert, chapter 5; and Diaper, Chapter 6). Electronic mail, however, does not count for some as CSCW, because it is "not really tuned (or tunable) to the needs of the work group" (Greif, 1988). Technologies which support routine work would appear to fall into a particularly controversial category. Traditional office automation systems come under this heading.
series	other
last changed	2003/04/23 15:14

_id	6a1d
authors	Woodbury, Robert F.
year	1988
title	The knowledge based representation and manipulation of geometry
source	Carnegie Mellon University
summary	An approach to the integration of geometric information in knowledge based systems is described as an architecture for geometric reasoning. The general requirements for this integration arise from the need for rich geometry representations in engineering domains and the conflicting demands of current geometric modelling and knowledge based systems. Four concepts are used as a basis: (1) Classes of spatial sets, which act by inheritance as a means for incremental definition by specialization, (2) Features, which denote evaluated portions of a geometric model, (3) Abstractions, which provide partial representations of geometric objects, and (4) Constraints through which spatial relationships are expressed. These four concepts combine in a synergistic manner to define the complete architecture. A prototype implementation of the architecture, built using object oriented programming techniques and a boundary based solid modeller, has been achieved and demonstrated through examples in the domains of robot task planning and automotive parts design.
series	thesis:PhD
email
last changed	2003/02/12 22:37

_id	0b4a
authors	Halbert, A.R., Todd, A.J.P. and Woodwark, J.R.
year	1988
title	Generalizing Active Zones for Set-Theoretic Solid Models
source	8 p. : ill Winchester, UK: IBM UK Scientific Centre, January, 1988. IBM UKSC Report 182. includes bibliography.
summary	A major drawback of the set-theoretic solid model is the global and non-unique way in which it is defined. In a recent paper, Rossignac and Voelcker introduced the concept of the active zone of a primitive or sub-model, which provides a localization of a set-theoretic model which is useful for a number of purposes. A more general, but simplified, definition of the active zone is presented which exploits the properties of the symmetric difference operator. A novel application of the active zone to the interactive graphical editing of set- theoretic solid models is also outlined
keywords	solid modeling, boolean operations, CSG
series	CADline
last changed	2003/06/02 13:58

_id	252a
authors	Reich, Yoram
year	1988
title	Machine Learning for Expert Systems : Motivation and Techniques
source	i-iii, 51 p. : some ill Pittsburgh, PA: Engineering Design Research Center, CMU, June, 1988. EDRC 12-27-88. includes bibliography. First generation expert systems suffer from two major problems: they are brittle and their development is a long, effortful process. Few successful expert systems for real world problems have been demonstrated. In this paper, learning, the key to intelligent behavior and expertise, is described as the answer to both expert systems deficiencies. Machine learning techniques are described, with their applicability to expert systems. A framework to organize machine learning techniques is provided. The description is followed by examples taken from the structural design domain. AI / learning / expert systems / structures / techniques. 37. Requicha, Aristides A. G. 'Mathematical Models of Rigid Solid Objects -- Production Automation Project.' Rochester, NY: College of Engineering & Applied Science, University of Rochester, November, 1977. [3], 37 p. : ill.
summary	Computational models of solid objects are potentially useful in a variety of scientific and engineering fields, and in particular in the field of design and manufacturing automation for the mechanical industries. In recent years a multitude of modelling systems have been implemented both by research laboratories and commercial vendors, but little attention has been paid to the fundamental theoretical issues in geometric modelling. This has led to severe difficulties in assessing current and proposed systems, and in distinguishing essential capabilities and limitations from user conveniences and efficiency considerations. This paper seeks a sharp mathematical characterization of 'rigid solids' in a manner that is suitable for studies in design and production automation. It draws heavily on established results in modern geometry and topology. Relevant results scattered throughout the mathematical literature are placed in a coherent framework and presented in a form accessible to engineers and computer scientists. A companion paper is devoted to a discussion of representational issues in the context set forth by this paper
keywords	solid modeling, geometric modeling
series	CADline
last changed	1999/02/12 15:09

For more results click below: