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	c341
authors	Cohen, Michael F. and Greenberg, Donald P.
year	1985
title	The Hemi-Cube: A Radiosity Solution for Complex Environments
source	SIGGRAPH '85 conference proceedings. July, 1985. vol. 19 ; no. 3: pp. 31-39 : ill. (some col.). includes bibliography
summary	This paper presents a comprehensive method to calculate object to object diffuse reflections within complex environments containing hidden surfaces and shadows. In essence, each object in the environment is treated as a secondary light source. The method provides an accurate representation of the 'diffuse' and 'ambient' terms found in typical image synthesis algorithms. The phenomena of 'color bleeding' from one surface to another, shading within shadow envelopes, and penumbras along shadow boundaries are accurately reproduced. Additional advantages result because computations are independent of viewer position. This allows the efficient rendering of multiple views of the same scene for dynamic sequences. Light sources can be modulated and object reflectivities can be changed, with minimal extra computation. The procedures extend the radiosity method beyond the bounds previously imposed
keywords	hidden surfaces, shadowing, computer graphics, geometric modeling, radiosity
series	CADline
last changed	2003/06/02 13:58

_id	78ca
authors	Friedland, P. (Ed.)
year	1985
title	Special Section on Architectures for Knowledge-Based Systems
source	CACM (28), 9, September
summary	A fundamental shift in the preferred approach to building applied artificial intelligence (AI) systems has taken place since the late 1960s. Previous work focused on the construction of general-purpose intelligent systems; the emphasis was on powerful inference methods that could function efficiently even when the available domain-specific knowledge was relatively meager. Today the emphasis is on the role of specific and detailed knowledge, rather than on reasoning methods.The first successful application of this method, which goes by the name of knowledge-based or expert-system research, was the DENDRAL program at Stanford, a long-term collaboration between chemists and computer scientists for automating the determination of molecular structure from empirical formulas and mass spectral data. The key idea is that knowledge is power, for experts, be they human or machine, are often those who know more facts and heuristics about a domain than lesser problem solvers. The task of building an expert system, therefore, is predominantly one of teaching" a system enough of these facts and heuristics to enable it to perform competently in a particular problem-solving context. Such a collection of facts and heuristics is commonly called a knowledge base. Knowledge-based systems are still dependent on inference methods that perform reasoning on the knowledge base, but experience has shown that simple inference methods like generate and test, backward-chaining, and forward-chaining are very effective in a wide variety of problem domains when they are coupled with powerful knowledge bases. If this methodology remains preeminent, then the task of constructing knowledge bases becomes the rate-limiting factor in expert-system development. Indeed, a major portion of the applied AI research in the last decade has been directed at developing techniques and tools for knowledge representation. We are now in the third generation of such efforts. The first generation was marked by the development of enhanced AI languages like Interlisp and PROLOG. The second generation saw the development of knowledge representation tools at AI research institutions; Stanford, for instance, produced EMYCIN, The Unit System, and MRS. The third generation is now producing fully supported commercial tools like KEE and S.1. Each generation has seen a substantial decrease in the amount of time needed to build significant expert systems. Ten years ago prototype systems commonly took on the order of two years to show proof of concept; today such systems are routinely built in a few months. Three basic methodologies-frames, rules, and logic-have emerged to support the complex task of storing human knowledge in an expert system. Each of the articles in this Special Section describes and illustrates one of these methodologies. "The Role of Frame-Based Representation in Reasoning," by Richard Fikes and Tom Kehler, describes an object-centered view of knowledge representation, whereby all knowldge is partitioned into discrete structures (frames) having individual properties (slots). Frames can be used to represent broad concepts, classes of objects, or individual instances or components of objects. They are joined together in an inheritance hierarchy that provides for the transmission of common properties among the frames without multiple specification of those properties. The authors use the KEE knowledge representation and manipulation tool to illustrate the characteristics of frame-based representation for a variety of domain examples. They also show how frame-based systems can be used to incorporate a range of inference methods common to both logic and rule-based systems.""Rule-Based Systems," by Frederick Hayes-Roth, chronicles the history and describes the implementation of production rules as a framework for knowledge representation. In essence, production rules use IF conditions THEN conclusions and IF conditions THEN actions structures to construct a knowledge base. The autor catalogs a wide range of applications for which this methodology has proved natural and (at least partially) successful for replicating intelligent behavior. The article also surveys some already-available computational tools for facilitating the construction of rule-based knowledge bases and discusses the inference methods (particularly backward- and forward-chaining) that are provided as part of these tools. The article concludes with a consideration of the future improvement and expansion of such tools.The third article, "Logic Programming, " by Michael Genesereth and Matthew Ginsberg, provides a tutorial introduction to the formal method of programming by description in the predicate calculus. Unlike traditional programming, which emphasizes how computations are to be performed, logic programming focuses on the what of objects and their behavior. The article illustrates the ease with which incremental additions can be made to a logic-oriented knowledge base, as well as the automatic facilities for inference (through theorem proving) and explanation that result from such formal descriptions. A practical example of diagnosis of digital device malfunctions is used to show how significantand complex problems can be represented in the formalism.A note to the reader who may infer that the AI community is being split into competing camps by these three methodologies: Although each provides advantages in certain specific domains (logic where the domain can be readily axiomatized and where complete causal models are available, rules where most of the knowledge can be conveniently expressed as experiential heuristics, and frames where complex structural descriptions are necessary to adequately describe the domain), the current view is one of synthesis rather than exclusivity. Both logic and rule-based systems commonly incorporate frame-like structures to facilitate the representation of large amounts of factual information, and frame-based systems like KEE allow both production rules and predicate calculus statements to be stored within and activated from frames to do inference. The next generation of knowledge representation tools may even help users to select appropriate methodologies for each particular class of knowledge, and then automatically integrate the various methodologies so selected into a consistent framework for knowledge. "
series	journal paper
last changed	2003/04/23 15:14

_id	ae09
authors	Lieberman, Henry
year	1985
title	There's More to Menu Systems Than Meets the Screen
source	SIGGRAPH '85 Conference Proceedings. July, 1985. vol. 19 ; no. 3: pp. 181-189 : ill. includes bibliography
summary	Love playing with those fancy menu-based graphical user interfaces, but afraid to program one yourself for your own application? Do windows seem opaque to you? Are you scared of Mice? Like what-you-see-is-what-you-get but don't know how to get-what-you-want-to-see on the screen? Everyone agrees using systems like graphical document illustrators, circuit designers, and iconic file systems is fun, but programming user interfaces for these systems isn't as much fun as it should be. Systems like the Lisp Machines, Xerox D- Machines, and Apple Macintosh provide powerful graphics primitives, but the casual applications designer is often stymied by the difficulty of mastering the details of window specification, multiple processes, interpreting mouse input, etc. This paper presents a kit called EZWin, which provides many services common to implementing a wide variety of interfaces, described as generalized editors for sets of graphical objects. An individual application is programmed simply by creating objects to represent the interface itself, each kind of graphical object, and each command. A unique interaction style is established which is insensitive to whether commands are chosen before or after their arguments. The system anticipates the types of arguments needed by commands preventing selection mistakes which are a common source of frustrating errors. Displayed objects are made 'mouse-sensitive' only if selection of the object is appropriate in the current context. The implementation of a graphical interface for a computer network simulation is described to illustrate how EZWin works
keywords	user interface, computer graphics
series	CADline
last changed	1999/02/12 15:09

_id	a0d4
id	a0d4
authors	Rosa Enrich, Andrea Carnicero, Gustavo Fornari & Pedro Orazzi
year	2004
title	ANALYSIS AND EVALUATION OF MATHEMATICAL LEARNING STRUCTURES
source	Proceedings of the Fourth International Conference of Mathematics & Design, Spetial Edition of the Journal of Mathematics & Design, Volume 4, No.1, pp. 13-21.
summary	Abstract: A series of practical tasks have been done under the general name of “Surfaces in invisible cities”. Each task was based on a story taken from the book The Invisible Cities by Italo Calvino. The research carried out allows to design a pedagogical project which makes evident , generates and connects several intentions, motivations and learning structures. It proposes the use of multi- level languages and readings. Therefore, each task takes more time than that of the proposed mathematical class. Its implementation generates a broader view than that seen at the time of design. From the detailed analysis of the results obtained, the following diverse pedagogical aspects of this work project arise: a. The use of several multiple intelligence: Howard Gardner (1985) found that a man has several distinct intelligence types among which Logical-Mathematical; Spatial; Linguistic -oriented; Musical; Intra-personal; Kinesthetic-Corporal; Interpersonal stand out. Only those types used in the task will be analyzed, making a brief description of each type. b. The architectonic-city planning aspects: architectonic-city planning interpretation of the space imagined after reading the text, with the purpose of identifying figures, shapes, volumes and colors which are expressed via an analogous space. They consist of visual, architectonic and territorial speculations without a rigorous spatial theory and it is pretended that they possess a technical precision at mathematical concept level. c. The mathematical contents: a study of the conical and square shapes present in the designs done and used in a creative manner in students’ compositions following the reading of the story chosen is carried out. An analysis of shapes is performed and mathematical problems are posed within the design context. Traditional sketching methods have been used in task solving and the possibilities offered by the virtual tools are analyzed. Emphasis has been put on the vertical and horizontal interchanges in the Chair, generating changes in knowledge transmission perspectives, thus allowing the sharing of contents, abilities and resources. The architectonic work imagined and created by the students will focus on these different working lines creating a harmonious and significant whole. The work is the result of multiple connections and creative proposals.
keywords	city, geometry, multiple intelligence
series	other
type	normal paper
email
last changed	2005/04/07 12:46

_id	63d0
authors	Carrara, Gianfranco and Novembri, Gabriele
year	1986
title	Constraint-bounded design search
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 146-157
summary	The design process requires continual checking of the consistency of design choices against given sets of goals that have been fulfilled. Such a check is generally performed by comparing abstract representations of design goals with these of the sought real building objects (RBO) resulting from complex intellectual activities closely related to the designer's culture and to the environment in which he operates. In this chapter we define a possible formalization of such representations concerning the goals and the RBO that are usually considered in the architectural design process by our culture in our environment. The representation of design goals is performed by expressing their objective aspects (requirements) and by defining their allowable values (performance specifications). The resulting system of requirements defines the set of allowable solutions and infers an abstract representation of the sought building objects (BO) that consists of the set of characteristics (attributes and relations) which are considered relevant to represent the particular kind of RBO with respect to the consistency check with design goals. The values related to such characteristics define the performances of the RBO while their set establishes its behaviour. Generally speaking, there is no single real object corresponding to an abstract representation but the whole class of the RBO that are equivalent with respect to the values assumed by the considered characteristics. The more we increase the number of these, as well as their specifications, the smaller the class becomes until it coincides with a single real object - given that the assessed specifications be fully consistent. On the other hand, the corresponding representation evolves to the total prefiguration of the RBO. It is not therefore possible to completely define a BO representation in advance since this is inferred by the considered goals and is itself a result of the design process. What can only be established in advance is that any set of characteristics assumed to represent any RBO consists of hierarchic, topological, geometrical and functional relations among the parts of the object at any level of aggregation (from components to space units, to building units, to the whole building) that we define representation structure (RS). Consequently the RS may be thought as the elementary structures that, by superposition and interaction, set up the abstract representation that best fit with design goals.
series	CAAD Futures
last changed	1999/04/03 17:58

_id	a833
authors	Jong, M. de
year	1986
title	A Spatial Relational Reference Model (3RM)
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 85-91
summary	In this chapter we hope to provide the reader with an impression of the objective, framework and possibilities of 3RM in the construction industry. In Dutch, 3RM stands for 'Ruimtelijk Relationeel Referentie Model' (Spatial Relational Reference Model). The model could begin to be used as an information-bearer in the building industry within which the specific trade information for each of the building participants could be interrelated, including drafting symbolism, building costs, physical qualities and building regulations. In this way, the model can be used as a means to a more efficient running of the building process and enabling the integration of information, at project level, provided by various building participants. The project should be defined in the same way as is a typical architectural project, whereby the actual development as well as the project management is carried out by architects. For the time being, development is limited to integral use at the design stage, but it also offers sufficient expansion possibilities to be able to function as a new communications model throughout the complete building process. We shall first provide information as to the origin, the objective and the execution of the project. Thereafter, we shall attempt to state the theoretical information problem within the building industry and the solution to this offered through 3RM. Finally, we shall report upon the results of the first phase of the 3RM project.
series	CAAD Futures
last changed	1999/04/03 17:58

_id	806f
authors	Woo, Tony C.
year	1985
title	A Combinatorial Analysis of Boundary Data Structure Schemata
source	IEEE Computer Graphics and Applications. March, 1985. vol. 5: pp. 19-27 : ill. includes bibliography
summary	While the design of an efficient 3-D data structure may be of theoretical interest, its real reward is the software speed- up in geometric algorithm for solid modeling, CAD/CAM and robotics application by using boundary data structures that are fast and use less storage. It is the objective of this article to provide techniques for designing new boundary data structures
keywords	CAD, CAM, data structures, solid modeling, algorithms, B-rep,techniques
series	CADline
last changed	2003/06/02 10:24

_id	avocaad_2001_16
id	avocaad_2001_16
authors	Yu-Ying Chang, Yu-Tung Liu, Chien-Hui Wong
year	2001
title	Some Phenomena of Spatial Characteristics of Cyberspace
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	"Space," which has long been an important concept in architecture (Bloomer & Moore, 1977; Mitchell, 1995, 1999), has attracted interest of researchers from various academic disciplines in recent years (Agnew, 1993; Benko & Strohmayer, 1996; Chang, 1999; Foucault, 1982; Gould, 1998). Researchers from disciplines such as anthropology, geography, sociology, philosophy, and linguistics regard it as the basis of the discussion of various theories in social sciences and humanities (Chen, 1999). On the other hand, since the invention of Internet, Internet users have been experiencing a new and magic "world." According to the definitions in traditional architecture theories, "space" is generated whenever people define a finite void by some physical elements (Zevi, 1985). However, although Internet is a virtual, immense, invisible and intangible world, navigating in it, we can still sense the very presence of ourselves and others in a wonderland. This sense could be testified by our naming of Internet as Cyberspace -- an exotic kind of space. Therefore, as people nowadays rely more and more on the Internet in their daily life, and as more and more architectural scholars and designers begin to invest their efforts in the design of virtual places online (e.g., Maher, 1999; Li & Maher, 2000), we cannot help but ask whether there are indeed sensible spaces in Internet. And if yes, these spaces exist in terms of what forms and created by what ways?To join the current interdisciplinary discussion on the issue of space, and to obtain new definition as well as insightful understanding of "space", this study explores the spatial phenomena in Internet. We hope that our findings would ultimately be also useful for contemporary architectural designers and scholars in their designs in the real world.As a preliminary exploration, the main objective of this study is to discover the elements involved in the creation/construction of Internet spaces and to examine the relationship between human participants and Internet spaces. In addition, this study also attempts to investigate whether participants from different academic disciplines define or experience Internet spaces in different ways, and to find what spatial elements of Internet they emphasize the most.In order to achieve a more comprehensive understanding of the spatial phenomena in Internet and to overcome the subjectivity of the members of the research team, the research design of this study was divided into two stages. At the first stage, we conducted literature review to study existing theories of space (which are based on observations and investigations of the physical world). At the second stage of this study, we recruited 8 Internet regular users to approach this topic from different point of views, and to see whether people with different academic training would define and experience Internet spaces differently.The results of this study reveal that the relationship between human participants and Internet spaces is different from that between human participants and physical spaces. In the physical world, physical elements of space must be established first; it then begins to be regarded as a place after interaction between/among human participants or interaction between human participants and the physical environment. In contrast, in Internet, a sense of place is first created through human interactions (or activities), Internet participants then begin to sense the existence of a space. Therefore, it seems that, among the many spatial elements of Internet we found, "interaction/reciprocity" Ñ either between/among human participants or between human participants and the computer interface Ð seems to be the most crucial element.In addition, another interesting result of this study is that verbal (linguistic) elements could provoke a sense of space in a degree higher than 2D visual representation and no less than 3D visual simulations. Nevertheless, verbal and 3D visual elements seem to work in different ways in terms of cognitive behaviors: Verbal elements provoke visual imagery and other sensory perceptions by "imagining" and then excite personal experiences of space; visual elements, on the other hand, provoke and excite visual experiences of space directly by "mapping".Finally, it was found that participants with different academic training did experience and define space differently. For example, when experiencing and analyzing Internet spaces, architecture designers, the creators of the physical world, emphasize the design of circulation and orientation, while participants with linguistics training focus more on subtle language usage. Visual designers tend to analyze the graphical elements of virtual spaces based on traditional painting theories; industrial designers, on the other hand, tend to treat these spaces as industrial products, emphasizing concept of user-center and the control of the computer interface.The findings of this study seem to add new information to our understanding of virtual space. It would be interesting for future studies to investigate how this information influences architectural designers in their real-world practices in this digital age. In addition, to obtain a fuller picture of Internet space, further research is needed to study the same issue by examining more Internet participants who have no formal linguistics and graphical training.
series	AVOCAAD
email
last changed	2005/09/09 10:48

_id	a127
authors	Rasdorf, William J. and Salley, George C.
year	1985
title	Generative Engineering Databases - Toward Expert Systems
source	Computers and Structures. Pergamon Press, 1985. vol. 22: pp. 11-15
summary	CADLINE has abstract only. Engineering data management, incorporating concepts of optimization with data representation, is receiving increasing attention. Research in this area promises advantages for many engineering applications, particularly those which use data innovatively. This paper presents a framework for a comprehensive, relational database management system that combines a knowledge base (KB) of design constraints with a database (DB) of engineering data items to achieve a 'generative database' - one which automatically generates new engineering design data according to the design constraints stored in the knowledge base. Thus, in addition to the designer and engineering design and analysis application programs, the database itself contributes to the design process. The KB/DB framework proposed here requires a database that is able to store all of the data normally associated with engineering design and to accurately represent the interactions between constraints and the stored data while guaranteeing its integrity. The framework also requires a knowledge base that is able to store all the constraints imposed upon the engineering design process. The goal sought is a central integrated repository of data, supporting interfaces to a wide variety of application programs and supporting processing capabilities for maintaining integrity while generating new data. The resulting system permits the unaided generation of constrained data values, thereby serving as an active design assistant. This paper suggests this new conceptual framework as a means of improving engineering data representation, generation, use, and management
keywords	management, optimization, synthesis, database, expert systems, civil engineering
series	CADline
last changed	2003/06/02 10:24

_id	ce52
authors	Abram, Greg, Weslover, Lee and Whitted, Turner
year	1985
title	Efficient Alias-Free Rendering using Bit-masks and Look-up Tables
source	SIGGRAPH '85 Conference Proceedings. July, 1985. vol. 19 ; no. 3: pp. 53-59 : ill. (some col.). includes bibliography
summary	The authors demonstrate methods of rendering alias-free synthetic images using a precomputed convolution integral. The method is based on the observation that a visible polygon fragment's contribution to an image is solely a function of its position and shape, and that within a reasonable level of accuracy, a limited number of shapes represent the majority of cases encountered in images commonly rendered. The basic technique has been applied to several different rendering algorithms. A version of the newly non-uniform sampling technique implemented in the same program but with different tables values was introduced
keywords	algorithms, computer graphics, anti-aliasing
series	CADline
last changed	2003/06/02 13:58

_id	8ae8
authors	Ayala, D., P. Brunet and Juan (et al)
year	1985
title	Object Representation by Means of Nominimal Division Quadtrees and Octrees
source	ACM Transactions on Graphics. January, 1985. vol. 4: pp. 41-59 : ill. includes bibliography
summary	Quadtree representation of two-dimensional objects is performed with a tree that describes the recursive subdivision of the more complex parts of a picture until the desired resolution is reached. At the end, all the leaves of the tree are square cells that lie completely inside or outside the object. There are two great disadvantages in the use of quadtrees as a representation scheme for objects in geometric modeling system: The amount of memory required for polygonal objects is too great, and it is difficult to recompute the boundary representation of the object after some Boolean operations have been performed. In the present paper a new class of quadtrees, in which nodes may contain zero or one edge, is introduced. By using these quadtrees, storage requirements are reduced and it is possible to obtain the exact backward conversion to boundary representation. Algorithms for the generation of the quadtree, boolean operation, and recomputation of the boundary representation are presented, and their complexities in time and space are discussed. Three- dimensional algorithms working on octrees are also presented. Their use in the geometric modeling of three-dimensional polyhedral objects is discussed
keywords	geometric modeling, algorithms, octree, quadtree, curves, curved surfaces, boolean operations
series	CADline
last changed	2003/06/02 13:58

_id	e191
authors	Fuchs, Henry, Goldfeather, Jack and Hultquist, Jeff P.
year	1985
title	Fast Spheres, Shadows, Textures, Transparencies, and Image Enhancements in Pixel-Planes
source	SIGGRAPH '85 Conference Proceedings. July, 1985. 1985. vol. 19 ; no. 3: pp. 111-120 : ill. includes bibliography
summary	Pixel-planes is a logic-enhanced memory system for raster graphics and imaging. Although each pixel-memory is enhanced with a one-bit ALU, the system's real power comes from a tree of one-bit address that can evaluate linear expressions Ax + By + C for every pixel (x,y) simultaneously, as fast as the ALUs and the memory circuits can accept the results. The development of a variety of algorithms that exploit this fast linear expression evaluation capability has started. The paper reports some of those results. Illustrated in this paper is a sample image from a small working prototype of the Pixel- planes hardware and a variety of images from simulations of a full-scale system. Timing estimates indicate that 30,000 smooth shaded triangles can be generated per second, or 21, 000 smooth-shaded and shadowed triangles can be generated per second, or over 25,000 shaded spheres can be generated per second. Image-enhancement by adaptive histogram equalization can be performed within 4 seconds on a 512 x 512 image
keywords	shadowing, image processing, algorithms, polygons, clipping, computer graphics, technology, hardware
series	CADline
last changed	2003/06/02 10:24

_id	c898
authors	Gero, John S.
year	1986
title	An Overview of Knowledge Engineering and its Relevance to CAAD
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 107-119
summary	Computer-aided architectural design (CAAD) has come to mean a number of often disparate activities. These can be placed into one of two categories: using the computer as a drafting and, to a lesser extent, modelling system; and using it as a design medium. The distinction between the two categories is often blurred. Using the computer as a drafting and modelling tool relies on computing notions concerned with representing objects and structures numerically and with ideas of computer programs as procedural algorithms. Similar notions underly the use of computers as a design medium. We shall return to these later. Clearly, all computer programs contain knowledge, whether methodological knowledge about processes or knowledge about structural relationships in models or databases. However, this knowledge is so intertwined with the procedural representation within the program that it can no longer be seen or found. Architecture is concerned with much more than numerical descriptions of buildings. It is concerned with concepts, ideas, judgement and experience. All these appear to be outside the realm of traditional computing. Yet architects discoursing use models of buildings largely unrelated to either numerical descriptions or procedural representations. They make use of knowledge - about objects, events and processes - and make nonprocedural (declarative) statements that can only be described symbolically. The limits of traditional computing are the limits of traditional computer-aided design systems, namely, that it is unable directly to represent and manipulate declarative, nonalgorithmic, knowledge or to perform symbolic reasoning. Developments in artificial intelligence have opened up ways of increasing the applicability of computers by acquiring and representing knowledge in computable forms. These approaches supplement rather than supplant existing uses of computers. They begin to allow the explicit representations of human knowledge. The remainder of this chapter provides a brief introduction to this field and describes, through applications, its relevance to computer- aided architectural design.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	00ed
authors	O'Leary, Dianne and Stewart, G.W.
year	1985
title	Data-Flow Algorithms for Parallel Matrix Computations
source	Communications of the ACM August, 1985. vol. 28: pp. 840-853. includes bibliography.
summary	In this article the authors develop some algorithms and tools for solving matrix problems on parallel processing computers. Operations are synchronized through data-flow alone, which makes global synchronization unnecessary and enables the algorithms to be implemented on machines with very simple operating systems and communication protocols. As examples, an algorithm that forms the main modules for solving Liapounov matrix equations is presented. The authors compare this approach to wave front array processors and systolic arrays, and note its advantages in handling missized problems, in evaluating variations of algorithms or architectures, in moving algorithms from system to system, and in debugging parallel algorithms on sequential machines
keywords	tools, algorithms, mathematics, parallel processing
series	CADline
last changed	2003/06/02 13:58

_id	62ff
authors	Peckham, R. J.
year	1985
title	Shading Evaluations with General Three- Dimensional Models
source	Computer Aided Design. September, 1985. vol. 17: pp. 305-310 : ill. includes bibliography
summary	The SHADOWPACK package of computer programs has been developed to facilitate shading evaluations, for the direct component of solar radiation, with general 3D models. An interactive solid modelling program allows the user to construct and view the 3D model before saving it for further analysis and display. Other programs permit the graphical display of the shading situation throughout the year, the quantitative assessment of energy received on different faces of the model, and the display of the distribution of energy received on particular faces by means of contour plots. The use of the computer graphics approach has proved particularly convenient because of the similarity between the techniques used for graphical and numerical algorithms
keywords	shading, solid modeling, evaluation, energy, computer graphics
series	CADline
last changed	2003/06/02 13:58

_id	6c66
authors	Perlin, Ken
year	1985
title	An Image Synthesizer
source	SIGGRAPH '85 Conference Proceedings. July, 1985. vol. 19 ; no. 3: pp. 287- 296 : ill. includes bibliography
summary	The authors introduce the concept of a Pixel Stream Editor. This forms the basis for an interactive synthesizer for designing highly realistic Computer Generated Imagery. The designer works in an interactive Very High Level programming environment which provides a very fast concept/implement/view iteration cycle. Naturalistic visual complexity is built up by composition of non-linear functions, as opposed to the more conventional texture mapping or growth model algorithms. Powerful primitives are included for creating controlled stochastic effects. The concept of 'solid texture' to the field of CGI is introduced. The authors have used this system to create very convincing representations of clouds, fire, water, stars, marble, wood, rock, soap films and crystals. The algorithms created with this paradigm are generally extremely fast, highly realistic, and asynchronously parallelizable at the pixel level
keywords	computer graphics, programming, algorithms, synthesis, realism
series	CADline
last changed	1999/02/12 15:09

_id	2699
authors	Piegl, L.
year	1985
title	Recursive Algorithms for the Representation of Parametric Curves and Surfaces
source	Computer Aided Design Butterworth & Co. (publishers) Ltd., June, 1985. vol. 17: pp. 225-230 : ill.
summary	includes a short bibliography. Recursive algorithms for the representation of parametric curves and surfaces are presented which are based upon a geometric property of the de Casteljau algorithm. The algorithms work with triangular and pyramidal arrays that provide an easy handing of the curve and the surface 'in a large' design
keywords	representation, recursion, algorithms, parametrization, curves, curved surfaces
series	CADline
last changed	2003/06/02 13:58

_id	6ed3
authors	Rasdorf, William J. and Storaasli, Olaf O.
year	1985
title	The Role of Computing in Engineering Education
source	Toward Expert Systems, Computers and Structures. Pergamon Press, July, 1985. vol. 20: pp. 11-15. Also published in: Advances and Trends in Structures and Dynamics edited by A. K. Noor and R. J. Hayduk
summary	Pergamon Press, 1985. --- Also Published in : Proceedings of the Symposium on Advances and Trends in Structures and Dynamics, Pergamon Press, George Washington University and the National Aeronautics and Space Administration, Washington, D.C. pp. 11-15, Oct.1984. The rapid advances occurring in interactive micro-computing and computer science have provided the engineer with a powerful means of processing, storing, retrieving, and displaying data. The effective use of computer technology in engineering processes and applications is recognized by many as the key to increased individual, company, and national productivity. The implications of this observation for the academic community are clear: we must prepare our students to use computer methods and applications as part of their fundamental education. The proper tradeoff between engineering fundamentals and computer science principles and practices is changing with many of the concepts of engineering now being packaged in algorithms or on computer chips. The components of an education should include operating system fundamentals, data structures, program control and organization, algorithms, and computer architectures. It is critically important for engineering students to receive an education that teaches them these fundamentals. This paper suggests that to convey the essentials of computer science to future engineers requires, in part, the addition of computer courses to the engineering curriculum. It also requires a strengthening of the computing content of many other courses so that students come to treat the computer as a fundamental component of their work. This is a major undertaking, but new engineers graduating with advanced computing knowledge will provide potentially significant future innovations in the engineering profession
keywords	CAE, education, civil engineering
series	CADline
last changed	2003/06/02 13:58

_id	a18b
authors	Samet, Hanan and Webber, Robert E.
year	1985
title	Storing a Collection of Polygons Using Quadtrees
source	ACM Transactions on Graphics July, 1985. vol. 4: pp. 182-222 : some ill. includes bibliography.
summary	An adaptation of the quadtree data structure that represents polygonal maps (i.e., collections of polygons, possibly containing holes) is described in a manner that is also useful for the manipulation of arbitrary collections of straight line segments. The goal is to store these maps without the loss of information that results from digitization, and to obtain a worst-case execution time that is not overly sensitive to the positioning of the map. Regular decomposition variant of the region quadtree is usedÔ h)000*°° ÔŒ to organize the vertices and edges of the maps. A number of related data organizations are proposed in an iterative manner until a method is obtained that meets the stated goals. The result is termed a PM (Polygonal Map) quadtree and is based on a regular decomposition Point Space quadtree (PS quadtree) that stores additional information about the edges at its terminal nodes. Algorithms are given for inserting and deleting line segments from a PM quadtree. Use of the PM quadtree to perform point location, dynamic line insertion, and map overlay is discussed. An empirical comparison of the PM quadtree with other quadtree-based representations for polygonal maps is also provided
keywords	data structures, quadtree, polygons, representation, point inclusion, algorithms
series	CADline
last changed	2003/06/02 10:24

_id	020d
authors	Shaviv, Edna
year	1986
title	Layout Design Problems: Systematic Approaches
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 28-52
summary	The complexity of the layout design problems known as the 'spatial allocation problems' gave rise to several approaches, which can be generally classified into two main streams. The first attempts to use the computer to generate solutions of the building layout, while in the second, computers are used only to evaluate manually generated solutions. In both classes the generation or evaluation of the layout are performed systematically. Computer algorithms for 'spatial allocation problems' first appeared more than twenty-five years ago (Koopmans, 1957). From 1957 to 1970 over thirty different programs were developed for generating the floor plan layout automatically, as is summarized in CAP-Computer Architecture Program, Vol. 2 (Stewart et al., 1970). It seems that any architect who entered the area of CAAD felt that it was his responsibility to find a solution to this prime architectural problem. Most of the programs were developed for batch processing, and were run on a mainframe without any sophisticated input/output devices. It is interesting to mention that, because of the lack of these sophisticated input/output devices, early researchers used the approach of automatic generation of optimal or quasioptimal layout solution under given constraints. Gradually, we find a recession and slowdown in the development of computer programs for generation of layout solutions. With the improvement of interactive input/output devices and user interfaces, the inclination today is to develop integrated systems in which the architectural solution is obtained manually by the architect and is introduced to the computer for the appraisal of the designer's layout solution (Maver, 1977). The manmachine integrative systems could work well, but it seems that in most of the integrated systems today, and in the commercial ones in particular, there is no route to any appraisal technique of the layout problem. Without any evaluation techniques in commercial integrated systems it seems that the geometrical database exists Just to create working drawings and sometimes also perspectives.
series	CAAD Futures
email
last changed	2003/05/16 20:58

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