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 121 to 140 of 175

_id 4b78
authors Piccolotto, Moreno and Rio, Olga
year 1995
title Structural Design Education with Computers
source Computing in Design - Enabling, Capturing and Sharing Ideas [ACADIA Conference Proceedings / ISBN 1-880250-04-7] University of Washington (Seattle, Washington / USA) October 19-22, 1995, pp. 285-298
summary In this paper, we discuss the importance of computer based simulation tools for the education of architects and civil engineers. We present our efforts to develop a program for the simulation of structures (CASDET). CASDET forms a microworld for planar structures. The program enables students to compose structures and to experiment interactively the effects of different geometry and load configurations. It tries to identify the proposed structure and controls its stability. Upon request of the student, it also processes displacements, internal forces (moments, shear forces etc.) and reaction forces on supports. The students can then visualise the desired information by interacting directly with the structure or member(s) of interest (see fig.1). We present different methods, with which students can visualise the results of their actions and discuss their implications in the educational context.
keywords Structural Design Education, Microworlds, Learning Environment, CAI
series ACADIA
email moreno@arch.ethz.ch, olgario@cc.csic.es
last changed 1999/03/29 15:22

_id acadia07_230
id acadia07_230
authors Qian, Cheryl Z.; Chen, Victor Y.; Woodbury, Robert F.
year 2007
title Participant Observation Can Discover Design Patterns in Parametric Modeling
source Expanding Bodies: Art • Cities• Environment [Proceedings of the 27th Annual Conference of the Association for Computer Aided Design in Architecture / ISBN 978-0-9780978-6-8] Halifax (Nova Scotia) 1-7 October 2007, 230-241
summary Our research aims to understand the mid-level patterns of work that recur across designers and tasks. Our users comprise active architects and civil engineers. The hypothesis is that making such patterns explicit will result in improved expert work practices, in better learning material and suggestions for improvements in parametric design. The literature shows that patterns express design work at a tactical level, above simple editing and below overall conception. We conducted a user experience study based on Bentley’s GenerativeComponents, in which geometry can be related, transformed, generated, and manipulated parametrically within a user-defined framework. After interviewing the system’s chief, we ran a participant-observer study in the January 2007 SmartGeometry workshop. We engaged designers through the role of tutor and simultaneously observed and discussed their design process. We found clear evidence of designers using patterns in the process and discerned several previously unknown patterns. In February at another 10-day workshop, we found more evidence supporting prior findings. The paper demonstrates that participant observation can be an efficient method of collecting patterns about designers’ work and introduces such new patterns. We believe these patterns may help designers work at more creative levels and may suggest new ideas of interest to CAD application developers.
series ACADIA
email cherylq@sfu.ca
last changed 2007/10/02 06:13

_id e3c1
authors Rasdorf, William J. and Fenves, Stephen J.
year 1980
title Design Specification Representation and Analysis
source Computing in Civil Engineering Conference Proceedings (2nd : 1980 : Baltimore, MD.). American Society of Civil Engineers, pp. 102- 111. CADLINE has abstract only
summary The conventional structures of decision tables, information networks, and outlines define the current methodology for the representation and use of design specifications. This paper explores the relationships at the interfaces between these three representational tools. New analysis strategies are presented that provide flexibility at the lower boundary of the information network by converting decision tables to subnetworks within the information network and by compressing multiple subtables into larger tables representing higher- level nodes in the network. Both generation and compression of the information network provide flexibility in organizing a specification. The ability to both generate and compress nodes and subnodes establishes a mean of representing all the relations among the data items of a specification and gives one more direct control over the level of detail of the information network. As a direct consequence of the ability to generate new nodes, new classifiers can be progressively attached to the nodes of the subnetwork, as well as to the nodes in the information network. As a result, specification requirements are more logically identified by the outline and requirements and data items which were previously hidden within decision table conditions and actions are now directly accessible from the outline. Conversely, items inconsequential to the outline can be compressed into nodes and removed from the outline. A computer program is presented that implements these network transformations. The program accurately represents the interface between the network and the decision table
keywords civil engineering, decision making, representation, analysis
series CADline
last changed 2003/06/02 11:58

_id 46b2
authors Rasdorf, William J. and Fenves, Stephen J.
year 1983
title Organization of a Structural Design Database
source Electronic Computation Conference Proceedings (8th : 1983 : Houston, TX). American Society of Civil Engineers, pp. 559-571. CADLINE has abstract only
summary This paper proposes a database schema that supports structural engineering design of buildings. An evaluation and comparison of hierarchical, network, and relational databases shows that relational databases are especially suited to a structural engineering design database. The proposed database schema represents the complex relationships between the components of a building-design database. The schema consists of a structural system hierarchy that relates abstract database components to basic building elements. In addition, it combines topology with attributes to achieve an integration that allows the representation of a broad range of common building configurations and structural systems. The user can combine a basic set of constructs to generate either a general or a very detailed description of a structure. The high degree of integration of topology and attributes yields a database that possesses desirable relational characteristics. The database provides efficient access to components based both on their location and on their attribute values. It also allows the user to add, delete, retrieve, and modify database components and values. The versatility and flexibility of the relational model make it a useful tool for managing building engineering data
keywords building, details, database, civil engineering, integration
series CADline
last changed 2003/06/02 11:58

_id 6105
authors Rasdorf, William J. and Fenves, Stephen J.
year 1986
title Constraint Enforcement in a Structural Design Database
source Journal of the Structural Division. American Society of Civil Engineers, December, 1986. vol. 112: pp. 2565-2577
summary During the design of a commercial structure, large amounts of information pertaining to all aspects of the design must be stored, accessed, and operated upon. A database management system (DBMS), composed of a central repository of data and the associated software for controlling accesses to it, provides one way to generate, represent, manage, and use this information. However, DBMSs are not presently structured in such a way that they can flexibly represent complex engineering constraint relationships, including those defined by codes, standards, and specifications. This paper examines structural design constraints and addresses the question of how they can be incorporated into DBMSs. It presents four representations of engineering constraints: the text of a design specification, the equations extracted from the specification, the dependency network among the constrained data items, and a relational DBMS model. The database model was implemented using a commercially available DBMS and the limitations of the implementation are explored. What is new in this DBMS model is that a constraint dependency subnetwork is associated directly with the stored data that it constrains. The implemented result is a new abstraction, consisting of a relation and a set of computations and checks, that enforces the relationships embodied in the dependency network. The database user need only initially define a set of rules and computed attributes. These are then used by the DBMS to automatically perform the appropriate checks and assignments. The database user is, to a significant degree, free of constraint checking concerns because the system itself knows what to do
keywords constraints management, civil engineering, database, DBMS
series CADline
last changed 2003/06/02 11:58

_id 27e8
authors Rasdorf, William J. and High, Stacey L.
year 1987
title Simplified Steel Compression Member Design
source Dynamics of Structures ASCE Structures Congress Proceedings. 1987. American Society of Civil Engineers, vol. D: pp. 352-367. CADLINE has abstract only
summary The American Institute of Steel Construction 'Specification for the Design, Fabrication, and Erection of Structural Steel Buildings' has made manual steel column design exceedingly time consuming and difficult. The objective of this paper is to present a simplified method of designing steel columns subjected to axial loads and moments for use in situations where automated design methods are inappropriate. Steel column design is based on the interaction equations of the AISC Specification. These equations are presented in terms of actual and allowable stresses and much time is required by a designer to manually determine the stresses and solve the equations. To simplify their solution, the interaction equations were reformulated and a set of parameters (multipliers) was introduced into them. The parameters were investigated to determine their validity, limits, and ranges of significant influence. They were then tabulated to provide quick and easy access for use. The modified interaction equations and the tabulated parameters constitute the results of this study. They are the physical tools that enable a designer to rapidly select initial steel column sections to satisfy design requirements and specification constraints. The analysis confirms that these tools can realistically and accurately be determined. The equations were algebraically derived and the tables were generated as a function of the properties of the sections. Thus, a new design method, combining the use of tabulated parameters with algebraically modified interaction equations, has been developed. This method greatly simplifies and speeds up the column section selection process
keywords civil engineering, structures, synthesis, design, methods
series CADline
last changed 2003/06/02 11:58

_id 81ae
authors Rasdorf, William J. and Parks, Linda M.
year 1986
title Expert Systems and Engineering Design Knowledge
source Electronic Computation Conference Proceedings (9th : 1986 : Birmingham, AL) American Society of Civil Engineers, pp. 28-42. CADLINE has abstract only.
summary Of all the contributions of artificial intelligence (AI), expert systems show some of the most significant promise for engineering applications. An expert system provides a framework for acquiring, representing, and using knowledge about a particular application's domain. The role of knowledge in engineering design merits closer attention so that AI-oriented computer-aided engineering (CAE) systems can be developed and maintained systematically. Because 'knowledge' in engineering applications is loosely defined, it is necessary to identify knowledge types and the correlations between them before widespread engineering design applications can be achieved. The types of domain knowledge; facts, procedures, judgments, and control; differ from the classes of that knowledge; creative, innovative, and routine. Feasible engineering tasks for expert systems can be determined based on these types and classes of knowledge. Prototype expert systems have been developed for civil engineering applications to assist with interpretation, design, planning, diagnosis, control, and other engineering system functions. A number of these are described herein. Interpretive tasks require reasoning about a task in light of the knowledge available, while generative tasks create potential solutions to be tested against constraints. Only after classifying the domain by type and level can the engineer select an appropriate knowledge-engineering tool for the domain being considered. The critical features to be weighed after problem classification are knowledge representation techniques, control strategies, interface requirements, compatibility with traditional systems, and economic considerations. After considering all of these factors in the selection of the expert system took, the engineer can then proceed with the acquisition of knowledge and the construction and use of the expert system
keywords design, knowledge, civil engineering, expert systems
series CADline
last changed 2003/06/02 11:58

_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 08:24

_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 11:58

_id a18d
authors Rasdorf, William J. and Storaasli, Olaf O.
year 1987
title Educational Fundamentals of Computer-Aided Engineering
source International Journal of Applied Engineering Education. Oxford: Pergamon Press, 1987. vol. 3: pp. 247-254
summary The role of computer science is increasing in nearly every engineering discipline. One of the dilemmas in engineering education today is how future engineers can best assimilate the advanced, yet fundamental, knowledge of computer science appropriate for their professional engineering career. This paper suggests that the role of the academic community must be to prepare engineering students to use computer methods and applications as a part of their fundamental engineering education. It is the responsibility of colleges and universities to incorporate contemporary computing fundamentals into their academic curriculum to improve the professional qualifications of their engineering graduates. This paper discusses current educational practices and their shortcomings as well as new options to reinforce and enhance the role of computing in engineering. The key ingredients, operating system fundamentals, data structures, program control and organization, algorithms, and computer architectures (relative to concurrent processing) are discussed. The 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 computational content of many others so that the student comes to treat the computer as a fundamental component of his work. Indeed this is a major undertaking but the benefits of advanced computer knowledge by new engineering graduates promises to provide significant future innovations in the engineering profession. The proper tradeoff between engineering fundamentals and computer science is changing with many of the concepts of engineering now being packaged in algorithms or on computer chips. The impact of advances in computer technology on engineering education are therefore discussed. Several of the benefits of enhanced computational expertise by engineers are enumerated and case studies of recent NASA initiatives whose success required that engineers possess an in-depth knowledge of computer science are presented
keywords CAE, civil engineering, education
series CADline
last changed 2003/06/02 08:24

_id 8312
authors Rasdorf, William J. and Wang, TsoJen E.
year 1986
title CDIS: An Engineering Constraint Definition and Integrity Enforcement System for Relational Databases
source Computers in Engineering International Conference Proceedings. 1986. American Society of Mechanical Engineers, vol. 2: pp. 273-280. CADLINE has abstract only
summary Database management systems (DBMS) are an essential component of the computer integrated manufacturing (CIM) environment. A database management system provides a powerful functionality for the storage, management, and use of engineering data. It is lacking, however, in its ability to deal with engineering constraints. In the past, constraint checking was performed by application programs. More recently DBMS's have been incorporating into their structure specifications for enforcing a limited set of integrity constraints and the mechanisms for invoking them automatically. To ensure the correctness of engineering data, an effective constraint management capability must be incorporated into any proposed engineering DBMS. This paper demonstrates how this can be done, proposes a systematic way to classify constraints so that integrity can be maintained efficiently, and discusses a prototype called CDIS which implements the concepts. This paper uses the relational database model to represent both engineering data and engineering constraints. Data integrity is defined and its enforcement through the use of engineering constraints is described. Existing methods for handling constraints are discussed. A new model that enables the engineer to associate design constraints with a relational database is presented and an example is given that demonstrates the model. Extensions to a DBMS to implement the concepts presented are described. No currently available DBMS provides the much needed capabilities proposed here
keywords civil engineering, relational database, constraints management
series CADline
last changed 2003/06/02 11:58

_id cc5a
authors Rasdorf, William J. and Wang, TsoJen E.
year 1986
title Expert System Integrity Maintenance for the Use of Engineering Data
source Computing in Civil Engineering Conference Proceedings (4th : 1986 : Boston, MA). American Society of Civil Engineers, pp. 654-668. CADLINE has abstract only
summary This paper describes a mechanism that enables one to automatically monitor and evaluate the use of engineering design data. The framework, associated with a relational database management system, combines a database with a set of constraints on the use of engineering data. This requires a database that stores all of the data normally associated with engineering design as well as all of the domain-dependent constraints imposed upon the use of the design data. Such a framework has been successfully constructed and is described in this paper. An example, based on constraints extracted from the AISC Specification, is presented and the performance of the framework is discussed. The proposed framework resides between a DBMS and its users and serves as an experienced expert consultant to the users. It embodies the knowledge of the specific domain of interest; in this case, allowable stresses in steel members. Whenever a user retrieves data from the database, the mechanism is activated. It interprets data request, applies the appropriate constraints, and provides the correct data. Its understanding of the semantics of both the data request and its own constraints insures the validity of data it selects to return to the user. All previous database integrity research concentrated on maintaining the integrity of the stored data, i.e., on guaranteeing the integrity of any static state of the database. This paper advocates a mechanism for checking data being retrieved from the database as well as for checking data being inserted into the database. It deals, therefore, with the correctness of data being selected for use
keywords information, civil engineering, expert systems, relational database
series CADline
last changed 2003/06/02 11:58

_id 66e5
authors Rasdorf, William J. and Wang, TsoJen E.
year 1987
title Generic Design Standards Processing in a Knowledge-based expert system Environment
source Design Process, National Science Foundation Workshop Proceedings. 1987. pp. 267-291. CADLINE has abstract only
summary Standards, codes, and specifications play an important role in the design of buildings, bridges, and other engineering systems. A design configuration must be checked against all standards to ensure that it is acceptable. This process of design conformance checking using standards is often very tedious. The successful automation of conformance checking is one of the components of a comprehensive computer-aided design system. In the past, standards were interpreted and converted into application program written in procedural programming languages such as FORTRAN. This approach is extremely inflexible and often error prone. To support a fully automated computer-aided design system, standards must be incorporated into the design process in a more generic and flexible manner. This paper investigates the feasibility of alternatively casting standards in a form suitable for processing in a knowledge-based expert system environment. The emergence of expert systems from artificial intelligence research has provided a technology that readily lends itself to the automation of design standards. Knowledge-based expert systems have become a powerful tool in tackling domains like design where some of the problem-solving knowledge is diverse and ill-structured. Using an expert system tool, a standard can be represented and processed independent of a CAD application program. Two prototype standards processing systems utilizing the production system approach have been constructed and are presented herein. Although the obvious direct translation casting the provisions of a standard as rules in a production system has its advantages, a more generic and flexible representation scheme is proposed herein. The approach advocated in this paper is to represent standards as databases of facts which can be readily and generically processed by an expert system. The database representation is derived from a unified view of standards obtained by using the standards modeling tools proposed by previous researchers in this field during the past decade. Building on this existing technology resulted in a knowledge- based standards processing architecture which is generic, modular, and flexible. An implementation of this architecture is presented and described
keywords knowledge base, standards, expert systems, civil engineering
series CADline
last changed 2003/06/02 11:58

_id 6683
authors Rasdorf, William J. and Wang, TsoJen E.
year 1987
title Spike : A Generic Design Standards Processing Expert System
source Southampton, UK: Computational Mechanics Publications, pp. 241-257. Also published in : Applications of Artificial Intelligence in Engineering International Conference Proceedings (2nd. : 1987 : Boston, MA.)
summary Standards, codes, and specifications play an important role in the design of buildings, bridges, and other engineering systems. A design configuration must be checked against all standards to ensure that it is acceptable. This process of design conformance checking using standards is often very tedious. The successful automation of conformance checking is one of the components of a comprehensive computer-aided design system. In that past, standards were interpreted and converted into application programs written in procedural programming languages such as FORTRAN. This approach is extremely inflexible and often error-prone. To support a fully automated computer-aided design system, standards must be incorporated into the design process in a more generic and flexible manner. This paper investigates the feasibility of alternatively casting standards in a form suitable for processing in a knowledge-based expert system environment. The emergence of expert systems from artificial intelligence research has provided a technology that readily lends itself to the automation of design standards. Knowledge-based expert systems have become a powerful tool in tackling domains like design where some of the problem-solving knowledge is diverse and ill-structured. Using an expert system tool, a standard can be represented and processed independent of a CAD application program. Two prototype standards processing systems utilizing the production system approach have been constructed and are presented herein. Although the obvious direct translation casting the provisions of a standard as rules in a production system has its advantages, a more generic and flexible representation scheme is proposed herein. The approach advocated in this paper is to represent standards as databases of facts which can be readily and generically processed by an expert system. The database representation is derived from a unified view of standards obtained by using the standards modeling tools proposed by previous researchers in this field during the past decade. Building on this existing technology resulted in a knowledge- based standards processing architecture which is generic, modular, and flexible. An implementation of this architecture is presented and described
keywords standards, civil engineering, expert systems
series CADline
last changed 2003/06/02 11:58

_id 4910
authors Rasdorf, William J. and Watson, Bruce R.
year 1987
title A Knowledge-Based Approach to Engineering Information Retrieval and Management
source London, UK: Chapman and Hall Ltd., 1987. pp. 267-295
summary Building design, construction, operation, maintenance, and control are all processes that have achieved various levels of computer use. Although the degree of computerization varies significantly, one common aspect of the computing needs of each process is an abundance of data in the form of tables, standards, project definition information, catalogs, etc. In most cases this data is stored in files which are independently used for input to stand-alone single-process application programs, such as a structural analysis application. The utility of these independent files is therefore limited to a single application. As concepts of integration of engineering applications evolved, the use of databases and database management systems (DBMS) increased. A number of issues of significant concern emerged. First, there is a need to retrieve data from many independent, possibly widely distributed databases. Second, there is a need for a uniform means of doing so. Third, such databases routinely undergo dynamic change. Changes in a database schema commonly result from the evolution of a design, from changes in the design process itself, and from changes in other subsequent downstream processes. Such continuing changes must be reflected in the database schemas and they subsequently require that application programs be updated and that online users be educated on a continuing basis. This chapter describes a knowledge-based expert system that provides access to and integration of the many underlying databases needed to support the building design/construction process. The unique aspect of the expert system presented in this chapter is its capture of the knowledge that an experienced human user incorporates in his search for data in a database, i.e., it seeks to identify and use the generic knowledge needed to operate a DBMS to retrieve data. This knowledge is used by the interface to enable both the online users and the application programs to request data without knowing the data's location or precisely how to ask for it. Further, the interface makes use of mechanisms that allow the user to request data without knowing the exact name by which it is stored in the database. In doing so it formalizes the levels of complexity of that knowledge and points out the multidisciplinary applications of the research results
keywords civil engineering, knowledge base, database, expert systems
series CADline
last changed 2003/06/02 08:24

_id 8331
authors Rasdorf, William J., Ulberg, Karen J. and Baugh, John W. Jr.
year 1987
title A Structure-Based Model of Semantic Integrity Constraints for Relational Databases
source International Journal of Engineering with Computers. Springer-Verlag, Spring, 1987. vol. 2: pp. 31- 39
summary Database management systems (DBMSs) are in widespread use because of the ease and flexibility with which they enable users to access large volumes of data. The use of DBMSs has spread from its origin in business applications to scientific and engineering applications as well. As engineers rely more and more on the computer for data storage, our ability to manually keep track of relationships between data and to ensure data accuracy is severely limited. The inherent fluctuations in engineering design data as well as its large volume, increase the difficulty of doing so. Ensuring data accuracy through the use of integrity constraints which limit or constrain the values of the data is a central aspect of DBMS use. Enforcing constraints (to the extend possible) is a job for the DBMS. This alleviates some of the burden placed on the user and database administrator to maintain the integrity of the database. In addition, it enables integrity constraints to be conceptually centralized and made available for inspection and modification instead of being scattered among application programs. Despite their importance, however, capabilities for handling integrity constraints in commercial DBMSs are limited and they lack adequate integrity maintenance support. In addition, a comprehensive theoretical basis for such support-the role of a constraint classification, representation, invocation, and use methodology-has yet to be developed. This paper presents a formalism that classifies semantic integrity constraints based on the structure of the relational database model. Integrity constraints are characterized by the portion of the database structure they access, whether one or more relations, attributes, or tuples. Thus, the model is completely general, allowing the identification, definition, and arbitrary specification of any constraint on a relational database. It also provides a basis for the implementation of a database integrity subsystem. Examples of each type of constraint are illustrated using a small engineering database, and various implementation issues are discussed
keywords civil engineering, relational database, constraints management
series CADline
last changed 2003/06/02 11:58

_id 8844
authors Rasdorf, William J.
year 1984
title Relational Database Modeling of Building Design Data
source Computing in Civil Engineering Conference Proceedings (3rd : 1984 : San Diego). American Society Of Civil Engineers, pp. 364-371. CADLINE has abstract only
summary This paper discusses the use of a relational database for representing the data gathered and derived during the building design process. In doing so, it considers the complexity of the relationships among a structure's topology, geometry, and attributes, and the critical requirements they impose on the development of a building design database. In the broad arena of computer-aided design, relational database management systems are establishing themselves as useful engineering tools. This is occurring at a time when engineers and architects are moving toward centralized and integrated databases of design information. In such a database, information is directly and readily available to all members of the design team, allowing them to work concurrently on an accurate representation of a wide variety of engineering design data. This paper presents the use of a relational database to model building design data and shows that the relationships among topology, geometry, and attributes can be successfully modeled relationally. The feasibility of interaction between engineering applications programs and the database is also indicated. Although the paper concentrates on structural design data for buildings, the relational model can also be used to represent the data of other engineering design disciplines as well as the data for other structures, assemblies, systems, and processes
keywords relational database, civil engineering, CAD
series CADline
last changed 2003/06/02 11:58

_id a36a
authors Rasdorf, William J.
year 1985
title Perspectives on Knowledge in Engineering Design
source Proceedings of the International Computers in Engineering Conference. Boston, MA: American Society of Mechanical Engineers, August, 1985. Vol. 2: pp. 249-253. CADLINE has abstract only
summary Of all the contributions of artificial intelligence (AI), expert systems show some of the most significant promise for engineering applications. Expert systems provide a framework for acquiring, representing, and using knowledge about a particular application's domain. The role of knowledge in engineering design merits closer attention so that AI- oriented computer-aided engineering (CAE) systems can be developed and maintained systematically. Because 'knowledge' in engineering applications is loosely defined, it is necessary to identify knowledge types and the correlations between them before widespread engineering design applications can be achieved. The types of domain knowledge; facts, procedures, judgments, and control; differ from the classes of that knowledge; creative, innovative, and routine. Feasible tasks for expert systems can be determined based on these types and classes of knowledge. Interpretive tasks require reasoning about a task in light of the knowledge available, while generative tasks create potential solutions to be tested against constraints. Only after classifying the domain by type and level can the engineer select an appropriate knowledge-engineering tool for the domain being considered. The critical features to be weighed after problem classification are knowledge representation techniques, control strategies, interface requirements, compatibility with traditional systems, and economic considerations. After considering all of these factors in the selection of the expert system tool, the engineer can then proceed with the acquisition of knowledge and the construction and the use of the expert system
keywords knowledge, AI, civil engineering, expert systems, CAE, representation
series CADline
last changed 2003/06/02 11:58

_id ee8f
authors Rasdorf, William J.
year 1987
title Extending Database Management Systems for Engineering Applications
source Computers in Mechanical Engineering (CIME). American Society of Mechanical Engineers, March, 1987. vol. 5: pp. 62-69
summary During the design of a manufactured component, large amounts of information pertaining to all aspects of the design must be stored, accessed, and operated upon. A database management system (DBMS), composed of a central repository of data and the associated software for controlling accesses to it and operations on it, provides one way to uniformly store, manage, and use this information. This paper presents a framework for an extension to relational database management systems that combines a set of engineering constraints with a database of engineering data items. The representation requires a database that is able to store all of the data normally associated with engineering design as well as the constraints imposed upon the engineering design process. A powerful and flexible constraint processing system is needed to adequately ensure that engineering data conforms to the limitations imposed upon it by the design process. Such a system must be capable of allowing constraints to be invoked at a variety of times, and provide numerous options for the user when violations are detected. This paper introduces a concept called structured constraints that integrates state- of-the-art advances in DBMSs and current research in engineering constraint processing to further enhance CAD system capabilities. It discusses the extensions to relational database theory that are needed to achieve such a constraint handling capability for mechanical engineering applications. The goal sought is a managed repository of data supporting interfaces to a wide variety of application programs and supporting processing capabilities for maintaining data integrity by incorporating engineering constraints. The Structured Constraint model is a general method for classifying semantic integrity constraints. It is based on the structure of the relational model and is therefore independent of any particular query language. In addition, it is a formalism that possesses conceptual clarity and generality which make it useful for representing and communicating arbitrary constraints. The key contribution of this formalism is its basis for a completely definable implementation of an engineering integrity system
keywords civil engineering, relational database, constraints management, management, DBMS
series CADline
last changed 2003/06/02 08:24

_id 08ba
authors Requicha, Aristides A.G.
year 1980
title Representations for Rigid Solids : Theory, Methods, and Systems
source Computing Surveys December, 1980. vol. 12: pp. 437-464 : ill. includes bibliography.
summary Computer-based systems for modeling the geometry of rigid solid objects are becoming increasingly important in mechanical and civil engineering, architecture, computer graphics, computer vision, and other fields that deal with spatial phenomena. At the heart of such systems are symbol structures (representations) designating 'abstract solids' (subsets of Euclidean space) that model physical solids. Representations are the sources of data for procedures which compute useful properties of objects. The variety and uses of systems embodying representations of solids are growing rapidly, but so are the difficulties in assessing current designs, specifying the characteristics that future systems should exhibit, and designing systems to meet such specifications. This paper resolves many of these difficulties by providing a coherent view, based on sound theoretical principles, of what is presently known about the representation of solids. The paper is divided into three parts. The first introduces a simple mathematical framework for characterizing certain important aspects of representations, for example, their semantic (geometric) integrity. The second part uses the framework to describe and compare all of the major known schemes for representing solids. The third part briefly surveys extant geometric modeling systems and then applies the concepts developed in the paper to the high-level design of a multiple- representation geometric modeling system which exhibits a level of reliability and versatility superior to that of systems currently used in industrial computer-aided design and manufacturing
keywords CAD, CAM, computational geometry, geometric modeling, representation,CSG, B-rep
series CADline
last changed 2003/06/02 11:58

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