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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Hits 1 to 20 of 33

_id 6387
authors Akin, Omer
year 1978
title How do Architects Design?
source Artificial Intelligence and Pattern Recognition in Computer Aided Design. North-Holland Publishing Company, 1978. pp. 65-98. includes bibliography
summary This study is proposes a descriptive model of the design behavior of architects. In the first section a framework for the model is proposed. In the second section the framework is tested against empirical data. 11 information processing mechanisms are observed in the data. Eight of these: information acquisition, problem interpretation, problem representation, solution generation, solution integration, solution evaluation, perception and sketching, are used in developing design solutions. The three remaining mechanisms: design 'plans,' transformation rules and design-symbols, represent the categories of the priori knowledge used in design. In the third section these three knowledge mechanisms are explored in detail using the results of two additional experiments with designers
keywords design methods, architecture, design process
series CADline
email oa04@andrew.cmu.edu
last changed 2003/05/17 08:09

_id 898a
authors Bay, J.H.
year 2002
title Cognitive Biases and Precedent Knowledge in Human and Computer-Aided Design Thinking
source CAADRIA 2002 [Proceedings of the 7th International Conference on Computer Aided Architectural Design Research in Asia / ISBN 983-2473-42-X] Cyberjaya (Malaysia) 18–20 April 2002, pp. 213-220
summary Cognitive biases (illusions) and potential errors can occur when using precedent knowledge for analogical, pre-parametric and qualitative design thinking. This paper refers largely to part of a completed research (Bay 2001) on how heuristic biases, discussed by Tversky and Kahneman (1982) in cognitive psychology, can affect judgement and learning of facts from precedents in architectural design, made explicit using a kernel of conceptual system (Tzonis et. al., 1978) and a framework of architectural representation (Tzonis 1992). These are used here to consider how such illusions and errors may be transferred to computer aided design thinking.
series CAADRIA
email akibayp@nus.edu.sg
last changed 2003/11/21 14:16

_id e1e8
authors Bezier, Pierre E.
year 1978
title General Distortion of an Ensemble of Biparametric Surfaces
source computer Aided Design. March, 1978. vol. 10: pp. 116-120 : ill. includes bibliography
summary When the shape of an object has been numerically defined, it is sometimes necessary to distort it to improve either its technical performance or its aesthetic appearance. After briefly recalling the major properties of space curves and surfaces defined by Bernstein polynomials, it is shown how the result can be automatically obtained by distorting an auxiliary triparametric set of references. The principle of an approximate method for high-order curves and surfaces is explained
keywords curves, curved surfaces, Bernstein, representation, Bezier, computational geometry
series CADline
last changed 2003/06/02 11:58

_id 35a7
authors Brown, André G.P.
year 2001
title Architectural critique through digital scenariobuilding. Augmenting Architectural Criticism and Narrative
source Proceedings of the Ninth International Conference on Computer Aided Architectural Design Futures [ISBN 0-7923-7023-6] Eindhoven, 8-11 July 2001, pp. 697-709
summary As an idea scenario-building has parallels the use of creative faking in related disciplines, most particularly, in contemporary art. The techniques involved in scenario-building and faking offer us enhanced ways of undertaking creative thinking and critical review of architecture and architectural projects. Critical review and theoretical analysis of architecture can be undertaken via a range of methods that Attoe (1978) classifies as Normative, Interpretive and Descriptive. Digital representation now offers us new ways of augmenting these critical styles in ways that have yet to be fully exploited, and possible means of exploitation are illustrated in this paper. In short the work described here shows how digital techniques can be used to enrich architectural investigation, critical reporting and debate.
keywords Digital Recreation, Scenario-Building, Narrative, Fake, Architectural Critique
series CAAD Futures
email andygpb@liv.ac.uk
last changed 2006/11/07 06:22

_id cf2011_p051
id cf2011_p051
authors Cote, Pierre; Mohamed-Ahmed Ashraf, Tremblay Sebastien
year 2011
title A Quantitative Method to Compare the Impact of Design Mediums on the Architectural Ideation Process.
source Computer Aided Architectural Design Futures 2011 [Proceedings of the 14th International Conference on Computer Aided Architectural Design Futures / ISBN 9782874561429] Liege (Belgium) 4-8 July 2011, pp. 539-556.
summary If we compare the architectural design process to a black box system, we can assume that we now know quite well both inputs and outputs of the system. Indeed, everything about the early project either feasibility studies, programming, context integration, site analysis (urban, rural or natural), as well as the integration of participants in a collaborative process can all be considered to initiate and sustain the architectural design and ideation process. Similarly, outputs from that process are also, and to some extent, well known and identifiable. We are referring here, among others, to the project representations or even to the concrete building construction and its post-evaluation. But what about the black box itself that produces the ideation. This is the question that attempts to answer the research. Currently, very few research works linger to identify how the human brain accomplishes those tasks; how to identify the cognitive functions that are playing this role; to what extent they operate and complement each other, and among other things, whether there possibly a chain of causality between these functions. Therefore, this study proposes to define a model that reflects the activity of the black box based on the cognitive activity of the human brain. From an extensive literature review, two cognitive functions have been identified and are investigated to account for some of the complex cognitive activity that occurs during a design process, namely the mental workload and mental imagery. These two variables are measured quantitatively in the context of real design task. Essentially, the mental load is measured using a Bakan's test and the mental imagery with eyes tracking. The statistical software G-Power was used to identify the necessary subject number to obtain for significant variance and correlation result analysis. Thus, in the context of an exploratory research, to ensure effective sample of 0.25 and a statistical power of 0.80, 32 participants are needed. All these participants are students from 3rd, 4th or 5th grade in architecture. They are also very familiar with the architectural design process and the design mediums used, i.e., analog model, freehand drawing and CAD software, SketchUp. In three experimental sessions, participants were asked to design three different projects, namely, a bus shelter, a recycling station and a public toilet. These projects were selected and defined for their complexity similarity, taking into account the available time of 22 minutes, using all three mediums of design, and this in a randomly manner to avoid the order effect. To analyze the two cognitive functions (mental load and mental imagery), two instruments are used. Mental imagery is measured using eye movement tracking with monitoring and quantitative analysis of scan paths and the resulting number and duration of participant eye fixations (Johansson et al, 2005). The mental workload is measured using the performance of a modality hearing secondary task inspired by Bakan'sworks (Bakan et al.; 1963). Each of these three experimental sessions, lasting 90 minutes, was composed of two phases: 1. After calibrating the glasses for eye movement, the subject had to exercise freely for 3 minutes while wearing the glasses and headphones (Bakan task) to get use to the wearing hardware. Then, after reading the guidelines and criteria for the design project (± 5 minutes), he had 22 minutes to execute the design task on a drawing table allowing an upright posture. Once the task is completed, the subject had to take the NASA TLX Test, on the assessment of mental load (± 5 minutes) and a written post-experimental questionnaire on his impressions of the experiment (± 10 minutes). 2. After a break of 5-10 minutes, the participant answered a psychometric test, which is different for each session. These tests (± 20 minutes) are administered in the same order to each participant. Thus, in the first experimental session, the subject had to take the psychometric test from Ekstrom et al. (1978), on spatial performance (Factor-Referenced Cognitive Tests Kit). During the second session, the cognitive style is evaluated using Oltman's test (1971). Finally, in the third and final session, participant creativity is evaluated using Delis-Kaplan test (D-KEFS), Delis et al. (2001). Thus, this study will present the first results of quantitative measures to establish and validate the proposed model. Furthermore, the paper will also discuss the relevance of the proposed approach, considering that currently teaching of ideation in ours schools of architecture in North America is essentially done in a holistic manner through the architectural project.
keywords design, ideation process, mental workload, mental imagery, quantitative mesure
series CAAD Futures
email pierre.cote@arc.ulaval.ca
last changed 2012/02/11 18:21

_id ea3c
authors Hillyard, R. and Braid, I.
year 1978
title Analysis of dimensions and tolerances in computer-aided mechanical design
source Computer Aided Design, vol.10, n.3, may 1978, pp. 161-166
summary The paper sets forth a theory to explain how dimensions and views combine to specify the shape of a mechanical component. It provides a method to determine whether a component is under, over, or exactly defined by a given dimensioning scheme. Measures for assessing the quality of a scheme are proposed. A solution is offered to a problem of tolerancing: given a toleranced dimensioning scheme, find the resulting tolerances between undimensioned parts of a component.
series journal paper
last changed 2003/04/23 13:14

_id 10a8
authors McCall, Raymond Joseph
year 1978
title On the structure and use of issue systems in design
source University of California, Berkeley
summary The purpose of this dissertation is to explain and justify the concept of issue serving-systems as a new paradigm for descriptive and normative models of design processes. This paradigm is based in general on Horst Rittel's "Argumentative Planning Paradigm" and in particular on Rittel's "Issue-Based Information System" --IBIS-- method. Like IBIS, the issue serving-system concept views design as consisting of the raising and answering of various questions, called issues. The addition of the issue serving-system concept to IBIS is the claim that the serving relationship is the main means for structuring issues into a system for design. That relationship is the one in which an issue A serves an issue B, by which it is meant that the answering of A is useful in deriving the answer to B. Collections of issues structured by this relationship are labelled "issue serving-systems." In the dissertation it is explained that an issue servingsystem has a quasi-hierarchical structure and has as its function the answering of a P!L issue, i.e., an issue of the form, "What should this plan be." Two projects are undertaken in order to demonstrate the normative significance of the issue serving-system concept. The first is to show that the concept forms the basis of a variety of techniques for mechanical (algorithmic) generation of issues and answers. The second is to show how the concept provides criteria for determining which issues should be dealt with and in what order. In particular, it is argued that a topdown breadth-first order of raising issues is best. These conclusions are incorporated into procedures for design, and two applications of these procedures are described. One application involves use of an interactive computer program written by the author. The other involves a non-computerized version of the method.
series thesis:PhD
last changed 2003/02/12 21:37

_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 Ř 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... Ř What is distributed? Ř What constraints govern the dynamics of such distributions in different time scales? Ř 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 13:14

_id avocaad_2001_09
id avocaad_2001_09
authors Yu-Tung Liu, Yung-Ching Yeh, Sheng-Cheng Shih
year 2001
title Digital Architecture in CAD studio and Internet-based competition
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 Architectural design has been changing because of the vast and creative use of computer in different ways. From the viewpoint of designing itself, computer has been used as drawing tools in the latter phase of design (Mitchell 1977; Coyne et al. 1990), presentation and simulation tools in the middle phase (Liu and Bai 2000), and even critical media which triggers creative thinking in the very early phase (Maher et al. 2000; Liu 1999; Won 1999). All the various roles that computer can play have been adopted in a number of professional design corporations and so-called computer-aided design (CAD) studio in schools worldwide (Kvan 1997, 2000; Cheng 1998). The processes and outcomes of design have been continuously developing to capture the movement of the computer age. However, from the viewpoint of social-cultural theories of architecture, the evolvement of design cannot be achieved solely by designers or design processes. Any new idea of design can be accepted socially, culturally and historically only under one condition: The design outcomes could be reviewed and appreciated by critics in the field at the time of its production (Csikszentmihalyi 1986, 1988; Schon and Wiggins 1992; Liu 2000). In other words, aspects of design production (by designers in different design processes) are as critical as those of design appreciation (by critics in different review processes) in the observation of the future trends of architecture.Nevertheless, in the field of architectural design with computer and Internet, that is, so-called computer-aided design computer-mediated design, or internet-based design, most existing studies pay more attentions to producing design in design processes as mentioned above. Relatively few studies focus on how critics act and how they interact with designers in the review processes. Therefore, this study intends to investigate some evolving phenomena of the interaction between design production and appreciation in the environment of computer and Internet.This paper takes a CAD studio and an Internet-based competition as examples. The CAD studio includes 7 master's students and 2 critics, all from the same countries. The Internet-based competition, held in year 2000, includes 206 designers from 43 counties and 26 critics from 11 countries. 3 students and the 2 critics in the CAD studio are the competition participating designers and critics respectively. The methodological steps are as follows: 1. A qualitative analysis: observation and interview of the 3 participants and 2 reviewers who join both the CAD studio and the competition. The 4 analytical criteria are the kinds of presenting media, the kinds of supportive media (such as verbal and gesture/facial data), stages of the review processes, and interaction between the designer and critics. The behavioral data are acquired by recording the design presentation and dialogue within 3 months. 2. A quantitative analysis: statistical analysis of the detailed reviewing data in the CAD studio and the competition. The four 4 analytical factors are the reviewing time, the number of reviewing of the same project, the comparison between different projects, and grades/comments. 3. Both the qualitative and quantitative data are cross analyzed and discussed, based on the theories of design thinking, design production/appreciation, and the appreciative system (Goodman 1978, 1984).The result of this study indicates that the interaction between design production and appreciation during the review processes could differ significantly. The review processes could be either linear or cyclic due to the influences from the kinds of media, the environmental discrepancies between studio and Internet, as well as cognitive thinking/memory capacity. The design production and appreciation seem to be more linear in CAD studio whereas more cyclic in the Internet environment. This distinction coincides with the complementary observations of designing as a linear process (Jones 1970; Simon 1981) or a cyclic movement (Schon and Wiggins 1992). Some phenomena during the two processes are also illustrated in detail in this paper.This study is merely a starting point of the research in design production and appreciation in the computer and network age. The future direction of investigation is to establish a theoretical model for the interaction between design production and appreciation based on current findings. The model is expected to conduct using revised protocol analysis and interviews. The other future research is to explore how design computing creativity emerge from the process of producing and appreciating.
series AVOCAAD
email aleppo@cc.nctu.edu.tw
last changed 2005/09/09 08:48

_id caadria2003_c6-2
id caadria2003_c6-2
authors Li Suping, Joo-Hwa Bay
year 2003
title A Cognitive Framework of Collaborative Design Between Architects and Manufacturer-Designers
source CAADRIA 2003 [Proceedings of the 8th International Conference on Computer Aided Architectural Design Research in Asia / ISBN 974-9584-13-9] Bangkok Thailand 18-20 October 2003, pp. 855-870
summary The widespread application of prefabricated products in building has made prefabrication an indispensable part of building processes. In this context, instead of handling every detail by architects themselves, some parts of architectural design have been transferred to manufacturer-designers. This inevitably brings about problems in the integration of prefabricated products and the specific buildings they serve. As a result, collaboration between architects and manufacturer-designers takes place in building processes in various forms and extents (non-, semi-, and full-collaboration). In this study, we aim to investigate collaborative design process from the cognitive aspect of design generation between architects and manufacturer-designers in terms of project-related products design. By applying the Kernel of Conceptual System theory (Tzonis et al., 1978), we intend to set up two empirical models in terms of design differences' formation in collaborative design process based on a case study with seeking the answers for the following research questions: 1. What kinds of design differences are raised in design processes? 2. Why the design differences are raised in design processes? 3. What implications could be made in developing computational models to facilitate collaborative design between architects and manufacturer-designers?
series CAADRIA
email sdep1193@nus.edu.sg, akibayp@nus.edu.sg
last changed 2003/12/02 06:47

_id 25c4
authors Henderson, Hazel
year 1978
title Creating Alternative Futures
source New York: Putnam
summary Creating Alternative Futures has pioneered many debates on how to guide industrial societies on healthier paths toward more equitable, ecologically sustainable human development. Henderson explains how GNP distorts the goal of human development worldwide. She points out misleading assumptions and a redefinition of health, wealth, and progress for humanity's long-term survival. The book predicts the sweep of democratization and the new "third sector" of grassroots globalists.
series other
last changed 2003/04/23 13:14

_id 4df6
authors Cohen, Elaine and Riesenfeld, Richard F.
year 1978
title An Incompatibility Projector Based on an Interpolant of Gregory
source computer Graphics and Image Processing. 1978. vol. 8: pp. 294-298. includes bibliography
summary This paper develops an 'incompatibility Projector' Qm, which is an intrinsically bivariate projector that is not the composition of two univariate projectors. Then it employs Qm to manifest a recent rational interpolant due to Gregory in projector form as a triple Boolean sum. This creates a mold for additional compatibility projectors which yield interpolants to functions that do not meet the ordinary compatibility constraints required for Boolean sum interpolation
keywords algorithms, computational geometry, curves, curved surfaces, mathematics, theory
series CADline
last changed 2003/06/02 08:24

_id 20c1
authors Alavalkama, Ilkka
year 1993
title Technical Aspects of the Urban Simulator in Tampere University of Technology
source Endoscopy as a Tool in Architecture [Proceedings of the 1st European Architectural Endoscopy Association Conference / ISBN 951-722-069-3] Tampere (Finland), 25-28 August 1993, pp. 35-46
summary The colour video recording Urban Simulator in TUT was built very early compared with the development of video systems. A contract for planning the simulator electronics, mechanics and camera systems was made in january 1978 with two TUT students: Jani Granholm (computer science and engineering) and Ilkka Alavalkama (machine design and automation). Ease of control and maintenance were asked by side of ”human movement inside coloured small-scale architectural models”. From the beginning, all components of the system were carefully tested and chosen from various alternatives. Financial resources were quite limited, which lead to a long building process and to self-planned and produced mechanical and electronical elements. Some optical systems were constructed by using elements from various manufacturers.

keywords Architectural Endoscopy
series EAEA
more http://info.tuwien.ac.at/eaea/
last changed 2005/09/09 08:43

_id 629c
authors Ball, A. A.
year 1978
title A Simple Specification of the Parametric Cubic Segment
source computer Aided Design. Business Press, May, 1978. vol. 10: pp. 181-182
summary A parametric cubic segment may be specified in many ways but most specifications require quantities peculiar to the parametric representation rather than the geometric properties of the curve segment. This paper shows that a three- dimensional cubic segment is specified completely by its end points, end slopes and one intermediate point
keywords parametrization, curves, curved surfaces, representation
series CADline
last changed 2003/06/02 08:24

_id 0fd5
authors Borkin, Harold J., McIntosh, John F. and Turner, James A.
year 1978
title The Development of Three-Dimensional Spatial Modeling Techniques for the Construction of Nuclear Power Plants
source SIGGRAPH-ACM Quarterly Report. August, 1978. pp. 26-30 : ill. includes bibliography
summary This paper presents the results of the first phase of a research project on the application of spatial modeling techniques to the process of planning and executing the construction of a nuclear power plant. A computer modeling technique, based on sets of polyhedra and spatial set operations, was developed and applied to modeling the components of a nuclear power plant. The objectives of the modeling are: To store and retrieve information about the various systems in the facility; to produce drawings of those systems from any angle in differing amounts of detail; to aid in the search for interference among the parts of the plant by identifying those elements that occupy the same space or are too close to each other; to calculate information such as surface area, length, and volume of selected elements of the plant; and to aid in finding the optimum construction sequence by simulating the construction of selected areas of the plant. Computer techniques are described for inputing information by digitizing directly from engineering drawings, for editing the spatial model, for management of the spatial and non-spatial data, and for graphic output from the model. The software is implemented on the University central time- sharing computer system and on a mini-computer system in the Architectural Research Laboratory
keywords geometric modeling, polyhedra, relational database, construction, synthesis, evaluation, design, applications
series CADline
last changed 2003/06/02 11:58

_id 0189
authors Brodlie, K.W. (editor)
year 1980
title Mathematical Methods in Computer Graphics and Design
source xi, 147 p. : ill. New York: Academic Press, 1980. includes subject index
summary Based on the proceeding of the conference on mathematical methods in computer graphics and design, organized by the Institute of Mathematics and Its Applications and held at the university of Leicester on september 28th, 1978
keywords algorithms, geometric modeling, techniques, computer graphics, mathematics
series CADline
last changed 2003/06/02 11:58

_id a8ca
authors Courtieux, Gerard
year 1981
title Man Machine Interface Problems in Computer Aided Architectural Design
source 1981. pp. 231-250 : ill. includes bibliography. -- discussion (pp. 247-250)
summary The author and two other researchers conducted a world-wide survey of existing computer aided architectural design programs in 1978. The purpose of the survey was to validate an earlier study of the architectural design process and to investigate problem areas in Computer Aided Architectural Design (CAAD). The survey indicated that two problems of man machine interaction in CAAD, though partly solved, remain a challenge for computer scientists: the description and graphical representation of three-dimensional objects. The formalization of the information collected in the survey, together with the experience of the author in teaching computer graphics to architecture students for the past ten years, is used to give some insight in these two problems and to make some recommendations for the improvement of the man machine interface in CAAD
keywords architecture, CAD, user interface
series CADline
last changed 1999/02/12 14:07

_id 0bd5
authors Dube, R., Herron, G.J. and Little, F.F. (et al)
year 1978
title SURFED -- An Interactive Editor for Free-Form Surfaces
source Computer Aided Design. March, 1978. vol. 10: pp. 111-115 : ill. includes bibliography
summary An editor is described for creating and modifying free-form surfaces. A modular system was developed in order to provide the researchers with a facility for communicating design ideas and new mathematical forms through an interactive graphical interface to a computer based model. To achieve this it was necessary to invent a new graphical construct called a `spider' for inputing three-dimensional parameters. This experimental system has the essential features of a large- scale implementation, with the capability of utilizing many new surface forms that have not yet been tried in actual applications
keywords curved surfaces, computer graphics, user interface
series CADline
last changed 2003/06/02 11:58

_id 2612
authors Flemming, Ulrich
year 1978
title Wall Representations of Rectangular Dissections and Their Use in Automated Space Allocation
source Environment and Planning B. 1978. vol. 5: pp. 215-232 : ill. includes bibliography
summary A procedure is described which generates dissections of rectangles into rectangular components in order to obtain solutions to space-allocation problems which are restricted through topological and dimensional constraints. Solutions are generated in two steps: step 1 determines basic geometric properties of the arrangements to be produced, and step 2 computes the dimensions of the spaces in such an arrangement. Both steps are based on `wall representations' of the solutions. These representations allow geometric relations and operations to be transformed into relations and operations defined on character strings. They furthermore allow the (possibly infinite) set of solutions to be systematically searched for a finite set of `principal options'. The importance linear-programming techniques for step 2 is described
keywords space allocation, linear programming, representation, CAD, design,automation, layout, synthesis
series CADline
email ujf@cmu.edu
last changed 2003/02/26 16:24

_id 0354
authors Goodman, Gary and Reddy, Raj D.
year 1978
title Alternative Control Structures for Speech Understanding Systems
source 1978 ? [13] p. : ill. includes bibliography Control structures are an essential part of any speech recognition system. They are the devices by which passive knowledge about the task and language is transformed into active and effective processes. In the chapter, three areas of control structures are defined and discussed: knowledge source interaction, knowledge source activation, and knowledge source focusing. Discussion relates the concepts presented to systems developed during the five-year ARPA speech understanding project. speech recognition / systems / control / structures / AI. 64. Goodman, Tim and Keith Unsworth. 'Manipulating Shape and Producing Geometric Continuity in B-spline Curves.' IEEE Computer Graphics and Applications. February, 1986. vol. 6: pp. 50-56 : ill. includes bibliography.
summary This article examines some of the desirable features of B- splines that make them particularly suitable for computer- aided design. First, a theoretical analysis is presented regarding the effects upon the shape of a design curve when the bias and tension parameters are allowed to vary in certain ways. Second, the concept of geometric continuity is discussed, and conditions are derived upon the control vertices to ensure that the design curve has second-order geometric continuity. Illustrations of B-spline curves are presented to support the theoretical conclusions
keywords computational geometry, B-splines, curves, CAD
series CADline
last changed 2003/06/02 11:58

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