Conceptual structural design through knowledge hierarchies.

摘要

Computer support for conceptual design still lags behind software available for analysis and detailed design. The Software Environment to Support the Early Phases in Building Design (SEED) project has the goal of providing design generation and exploration capabilities to aid in the conceptual design of buildings, from architectural programming and layout to enclosure design and structural configuration. The current work presents a component of the efforts of the SEED-Config Structure group in providing computer support for conceptual structural design.; The Building Entity and Technology (BENT) approach models data about building elements in a general, hierarchical form, where design evolution is represented by the growing specificity of the design description. Two methods of system-supported design generation are provided: case-based reasoning and application of knowledge rules. The knowledge rules, termed technologies, and how they are specified and used are the primary focus of this thesis.; In the BENT approach, conceptual structural engineering knowledge is modularized into technology nodes arranged in a directed "AND/OR" graph, where OR nodes represent alternative design decisions and AND nodes represent problem decomposition. In addition, nodes in the graph may also be specified as having AND/OR incoming arcs thus reducing the duplication of nodes and enhancing the representational power of the approach. In order to facilitate the incorporation of new knowledge into the system, and verify and/or change the knowledge already in the system, the data model and the interface allow for dynamic creation, browsing, and editing of technology nodes.; Design generation through the use of the knowledge hierarchy involves the conditional application of nodes according to the design context as represented by the building element(s) under consideration. Each application of a technology node expands the design of building elements by increasing the detail of the design description or by decomposing the elements into less abstract components. In addition, support for simultaneous design of multiple elements and for iteration control are also provided.; An important feature of the BENT approach is that the generative knowledge (i.e., the technology hierarchy) is detached from the information repository (i.e., the database of entities which make up the building). This allows the technology hierarchies to be used in a modular fashion from building problem to building problem.