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

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_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	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	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	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	1447
authors	Meyer, B.
year	1988
title	Object Oriented Software Construction
source	Prentice-Hall, Englewood-Cliff NJ
summary	Object-Oriented Software Construction, second edition is the comprehensive reference on all aspects of object technology, from design principles to O-O techniques, Design by Contract, O-O analysis, concurrency, persistence, abstract data types and many more. Written by a pioneer in the field, contains an in-depth analysis of both methodological and technical issues.
series	other
last changed	2003/04/23 15:14

_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	5f4b
authors	Coyne, R.D.
year	1988
title	Logic Models of Design
source	Pitman, London
summary	This monograph places design in a theoretical context which applies developments in knowledge-based systems, logic programming and planning to design. It addresses two important design issues: the interpretation of designs, which concerns the discovery of implicit design attributes, a key activity in design evaluation that can be modelled by deductive inference in logic programming; and the process of generation, whereby a design description is produced which exhibits these implicit design attributes. Implicit attributes can be seen as analogous to the semantic content of natural language utterances. The work presented here is mainly concerned with design generation, and an operational model of design is investigated in which operations on processes are treated in a similar way to operations on form. It is argued that there are advantages in representing control knowledge as rules in a design system, and that logic is an effective medium for this purpose. This is demonstrated by means of programs developed in Prolog and C using the example of spatial layout in buildings. Primarily, this book is directed at those in artificial intelligence (AI) involved in logic programming, planning and expert systems. However, since AI techniques are finding widespread application in industry, the use of an architectural design example makes this work relevant to architects, designers, engineers and developers of intelligent architectural design software.
series	other
email
last changed	2003/04/23 15:14

_id	e7a8
authors	Emde, H.
year	1988
title	Geometrical Fundamentals for Design and Visualization of Spatial Objects
source	CAAD futures ‘87 [Conference Proceedings / ISBN 0-444-42916-6] Eindhoven (The Netherlands), 20-22 May 1987, pp. 171-178
summary	Every architectural object is a 3-dimensional entity of the human environment, haptically tangible and optically visible. During the architectural process of planning every object should be designed as a body and should be visualized in pictures. Thus the parts of construction get an order in space and the steps of construction get an order in time. The ideal planning object is a simulated anticipation of the real building object, which is to be performed later on. The possibility to relate the planning object immediately to the building object relies on the fact that they both have the same "geometry" This means: both can be described in the same geometric manner. Creating and visualizing spatial objects is based on geometrical fundamentals. Theoretical knowledge and practical control of these fundamentals is essential for the faultless construction and the realistic presentation of architectural objects. Therefore they have to be taught and learned thoroughly in the course of an architectural education. Geometrical design includes the forming of object- models (geometry of body boundaries), the structuring of object-hierarchies (geometry of body combinations) and the colouring of objects. Geometrical visualization includes controlling the processes of motion, of the bodies (when moving objects) and of the center of observation (when moving subjects) as well as the representation of 3-dimensional objects in 2- dimensional pictures and sequences of pictures. All these activities of architects are instances of geometrical information processing. They can be performed with the aid of computers. As for the computer this requires suitable hardware and software, as for the architect it requires suitable knowledge and capabilities to be able to talk about and to recall the perceivable objects and processes of the design with logic abstracts (language of geometry). In contrast to logical, numerical and textual informations the geometric informations concerning spatial objects are of much higher complexity. Usually these complexes of information are absorbed, processed and transmitted by the architect in a perceptive manner. The computer support in the field of geometry assumes that the processing of perceptions of the human consciousness can be converted by the computer as a framework of logical relations. Computer aided construction and representation require both suited devices for haptical and optical communication and suitable programs in particular.
series	CAAD Futures
last changed	1999/04/03 17:58

_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	8385
authors	Holtz, Neal M. and Rasdorf, William J.
year	1988
title	An Evaluation of Programming Languages and Language Features for Engineering Software Development
source	International Journal of Engineering with Computers. Springer-Verlag, 1988. vol. 3: pp. 183-199
summary	Also published as 'Procedural Programming Languages for the Development of CAD and CAE Systems Software,' in the proceedings of ASME International Conference on Computers in Engineering (1987 : New York, NY). The scope of engineering software has increased dramatically in the past decade. In its early years, most engineering applications were concerned solely with solving difficult numerical problems, and little attention was paid to man- machine interaction, to data management, or to integrated software systems. Now computers solve a much wider variety of problems, including those in which numerical computations are less predominant. In addition, completely new areas of engineering applications such as artificial intelligence have recently emerged. It is well recognized that the particular programming language used to develop an engineering application can dramatically affect the development cost, operating cost. reliability, and usability of the resulting software. With the increase in the variety, functionality, and complexity of engineering software, with its more widespread use, and with its increasing importance, more attention must be paid to programming language suitability so that rational decisions regarding language selection may be made. It is important that professional engineers be aware of the issues addressed in this paper, for it is they who must design, acquire, and use applications software, as well as occasionally develop or manage its development. This paper addresses the need for engineers to possess a working knowledge of the fundamentals of computer programming languages. In pursuit of this, the paper briefly reviews the history of four well known programming languages. It then attempts to identify and to look critically at the attributes of programming languages that significantly affect the production of engineering software. The four procedural programming languages chosen for review are those intended for scientific and general purpose programming, FORTRAN 77, C, Pascal, and Modula-2. These languages are compared and some general observations are made. As it is felt important that professional engineers should be able to make informed decisions about programming language selection, the emphasis throughout this paper is on a methodology of evaluation of programming languages. Choosing an appropriate language can be a complex task and many factors must be considered. Consequently, fundamentals are stressed
keywords	programming, engineering, languages, software, management, evaluation, FORTRAN, C, PASCAL, MODULA-2, CAD, CAE
series	CADline
last changed	2003/06/02 13:58

_id	diss_howe
id	diss_howe
authors	Howe, Alan Scott
year	1988
title	A new paradigm for life-cycle management of kit-of-parts building systems
source	UNIVERSITY OF MICHIGAN , PhD
summary	The research described in this dissertation brings together various technologies in manufacturing and information management and suggests a new paradigm for the design, manufacture, and lifetime use of artifacts using kit-of-parts systems and rule-based assembly. The questions are asked: If architects, designers, and users were given direct online connection to real-time design information sources and fabrication processes, and have the ability to monitor and control the current state of designed objects throughout the objects' lifetime, how would the entire life-cycle of a product be affected, and how would design processes change? During the course of the research described in this dissertation, a series of simulations and experiments were conducted which produced a computer-based simulated design, manufacture, and use environment wherein these questions could begin to be answered. A kit-of-parts model building system was devised which could be used to design model buildings in virtual form by downloading virtual representations of the components from the Internet and assembling them into a desired form. The virtual model building could then be used to order the manufacture of real components online, and remotely controlled robots used to assemble the actual building on the site. Through the use of special hardware manufactured into the components, real-time remote monitoring and control of the current state of the finished model building was affected during the building's lifetime. The research establishes the feasibility of an online life-cycle environment where a virtual representation of an artifact is created and used to both manufacture a real-world counterpart and also monitor and control the current state of the real-world object. The state-of-the-art of pertinent technologies were explored through literature searches and experiments. Data representation, rule-based design techniques, robotics, and digital control were studied, and a series of design principles established which lend themselves toward a life-cycle management paradigm. Several case studies are cited which show how the design principles and life-cycle management environment can be applied to real buildings and other artifacts such as vehicles and marine structures. Ideas for expanded research on the life-cycle management paradigm are cited.
series	thesis:PhD
email
more	http://wwwlib.umi.com/dissertations/fullcit/9909905
last changed	2003/11/20 19:57

_id	4da4
authors	Jordan, J. Peter
year	1988
title	ARCH 431: Computer-Aided Design
source	Computing in Design Education [ACADIA Conference Proceedings] Ann Arbor (Michigan / USA) 28-30 October 1988, pp. 187-200
doi	https://doi.org/10.52842/conf.acadia.1988.187
summary	There is a significant variance in the way computer courses are taught at various institutions around the country. Generally, it is useful to think of these courses falling either into a "tool-building" or a "tool-using" category. However, within either category, there is a variety of focus on the application of the "tool". Two courses have been developed at the University of Hawaii at Manoa which deal with computer applications. The first course is more quantitatively oriented, encouraging students to explore ways of dealing with problems in a more complex and substantial manner. This paper deals with the second course whose focus has shifted toward design issues, using the computer as a tool to explore these issues. This course exposes the student, not to training on a specific computer-aided drafting system, but to issues in computer-aided design which include hardware and software systems, human-machine interface, and the nature of the design process. This course seems to be an appropriate model for introducing computer-aided design to undergraduates in a professional design program.
series	ACADIA
email
last changed	2022/06/07 07:52

_id	8403
authors	Mitchell, William J., Liggett, Robin S. and Tan, Milton
year	1988
title	The Topdown System and its use in Teaching - An Exploration of Structured, Knowledge-Based Design
source	Computing in Design Education [ACADIA Conference Proceedings] Ann Arbor (Michigan / USA) 28-30 October 1988, pp. 251-262
doi	https://doi.org/10.52842/conf.acadia.1988.251
summary	The Topdown System is a shell for use in developing simple (but we believe non-trivial) knowledge-based CAD systems. It provides a data structure, graphics capabilities, a sophisticated user interface, and programming tools for rapid construction of knowledge bases. Implementation is for Macintosh, Macintosh II, IBM PC/AT, PS12, and Sun workstations. The basic idea is that of top-down design - beginning with a very abstract representation, and elaborating that, in step-by-step fashion, into a complete and detailed representation. The basic operations are real-time parametric variation of designs (using the mouse and slide bar) and substitution of objects. Essentially, then, a knowledge-base in Topdown implements a kind of parametric shape grammar. The main applications of Topdown are in introductory teaching of CAD, and (since it provides a very quick and easy way for a user to develop detailed geometric models) to provide a uniform front-end for a variety of different applications. The shell, and some example knowledge-bases, are publicly available. This paper discusses the principles of the Topdown Shell, the implementation of knowledge bases within it, and a variety of practical design applications.
series	ACADIA
email
last changed	2022/06/07 07:58

_id	11cb
id	11cb
authors	Oguzhan Özcan
year	2004
title	MATHEMATICS AND DESIGN EDUCATION
source	Proceedings of the Fourth International Conference of Mathematics & Design, Special Edition of the Journal of Mathematics & Design, Volume 4, No.1, pp. 199-203.
summary	Many people believe that mathematical thought is an essential element of creativity. The origin of this idea in art dates back to Plato. Asserting that aesthetics is based on logical and mathematical rules, Plato had noticed that geometrical forms were “forms of beauty” in his late years. Unlike his contemporaries, he had stressed that the use of geometrical forms such as lines, circles, planes, cubes in a composition would aid to form an aesthetics. The rational forms of Plato and the rules of geometry have formed the basis of antique Greek art, sculpture and architecture and have influenced art and design throughout history in varying degrees. This emphasis on geometry has continued in modern design, reflected prominently by Kandinsky’s geometric classifications . Mathematics and especially geometry have found increasing application in the computer-based design environment of our day. The computer has become the central tool in the modern design environment, replacing the brush, the paints, the pens and pencils of the artist. However, if the artist does not master the internal working of this new tool thoroughly, he can neither develop nor express his creativity. If the designer merely learns how to use a computer-based tool, he risks producing designs that appear to be created by a computer. From this perspective, many design schools have included computer courses, which teach not only the use of application programs but also programming to modify and create computer-based tools. In the current academic educational structure, different techniques are used to show the interrelationship of design and programming to students. One of the best examples in this area is an application program that attempts to teach the programming logic to design students in a simple way. One of the earliest examples of such programs is the Topdown Programming Shell developed by Mitchell, Liggett and Tan in 1988 . The Topdown system is an educational CAD tool for architectural applications, where students program in Pascal to create architectural objects. Different examples of such educational programs have appeared since then. A recent fine example of these is the book and program called “Design by Number” by John Maeda . In that book, students are led to learn programming by coding in a simple programming language to create various graphical primitives. However, visual programming is based largely on geometry and one cannot master the use of computer-based tools without a through understanding of the mathematical principles involved. Therefore, in a model for design education, computer-based application and creativity classes should be supported by "mathematics for design" courses. The definition of such a course and its application in the multimedia design program is the subject of this article.
series	other
type	normal paper
email
last changed	2005/04/07 15:36

_id	98bd
authors	Pea, R.
year	1993
title	Practices of Distributed Intelligence and Designs for Education
source	Distributed Cognitions, edited by G. Salomon. New York, NY: CambridgeUniversity Press
summary	v Knowledge is commonly socially constructed, through collaborative efforts... v Intelligence may also be distributed for use in designed artifacts as diverse as physical tools, representations such as diagrams, and computer-user interfaces to complex tasks. v Leont'ev 1978 for activity theory that argues forcibly for the centrality of people-in-action, activity systems, as units of analysis for deepening our understanding of thinking. v Intelligence is distributed: the resources that shape and enable activity are distributed across people, environments, and situations. v Intelligence is accomplished rather than possessed. v Affordance refers to the perceived and actual properties of a thing, primarily those functional properties that determine how the thing could possibly be used. v Norman 1988 on design and psychology - the psychology of everyday things" v We deploy effort-saving strategies in recognition of their cognitive economy and diminished opportunity for error. v The affordances of artifacts may be more or less difficult to convey to novice users of these artifacts in the activities to which they contribute distributed intelligence. v Starts with Norman's seven stages of action Ø Forming a goal; an intention § Task desire - clear goal and intention - an action and a means § Mapping desire - unable to map goal back to action § Circumstantial desire - no specific goal or intention - opportunistic approach to potential new goal § Habitual desire - familiar course of action - rapidly cycle all seven stages of action v Differentiates inscriptional systems from representational or symbol systems because inscriptional systems are completely external, while representational or symbol systems have been used in cognitive science as mental constructs. v The situated properties of everyday cognition are highly inventive in exploiting features of the physical and social situation as resources for performing a task, thereby avoiding the need for mental symbol manipulations unless they are required by that task. v Explicit recognition of the intelligence represented and representable in design, specifically in designed artifacts that play important roles in human activities. v Once intelligence is designed into the affordances properties of artifacts, it both guides and constrains the likely contributions of that artifact to distributed intelligence in activity. v Culturally valued designs for distributed intelligence will change over time, especially as new technology becomes associated with a task domain. v If we treat distributed intelligence in action as the scientific unit of analysis for research and theory on learning and reasoning... Ø What is distributed? Ø What constraints govern the dynamics of such distributions in different time scales? Ø Through what reconfigurations of distributed intelligence might the performance of an activity system improve over time? v Intelligence is manifest in activity and distributed in nature. v Intelligent activities ...in the real world... are often collaborative, depend on resources beyond an individual's long-term memory, and require the use of information-handling tools... v Wartofsky 1979 - the artifact is to cultural evolution what the gene is to biological evolution - the vehicle of information across generations. v Systems of activity - involving persons, environment, tools - become the locus of developmental investigation. v Disagrees with Salomon et al.'s entity-oriented approach - a language of containers holding things. v Human cognition aspires to efficiency in distributing intelligence - across individuals, environment, external symbolic representations, tools, and artifacts - as a means of coping with the complexity of activities we often cal "mental." "
series	other
last changed	2003/04/23 15:14

_id	861a
authors	Sedas, Sergio W. and Talukdar, Sarosh N.
year	1987
title	A Disassembly Planner for Redesign
source	The Winter Annual Meeting of the American Society of Mechanical Engineers. Symposium of Intelligent and Integrated Manufacturing Analysis and Synthesis. December, 1987. Pittsburgh, PA: Engineering Design Research Center, CMU, 1988. [6] p. : ill. includes bibliography
summary	This paper describes an algorithm for generating plans for disassembling given objects. The plans are produced by a set of knowledge sources acting on a set of representations for the object. Both sets are arbitrarily expandable, so programs using the approach can grow continually in capability. Our present complement of knowledge sources and representations can tackle relatively difficult problems. Three examples are included. The first requires a good bit of geometric reasoning before appropriate subassemblies can be selected. The second and third require certain movable parts to be repositioned before disassembly can be achieved
keywords	algorithms, representation, synthesis, assemblies, knowledge, reasoning, mechanical engineering
series	CADline
last changed	2003/06/02 13:58

_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	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	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

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