Building Knowledge about Buildings Matt Young and Eyal Amir University of Illinois, Urbana-Champaign

The Problem Need a way to represent information about buildings. A wealth of information exists in floor plans, but what information do we need? How to encode it?

Our Goals A general framework for representing buildings which is: Simple enough to add data quickly/automatically. Complete enough to accurately represent the structure of a building. Able to answer queries regarding that structure.

Overview Previous Work Overview of Our Language Comparison with Current Technology Other Applications Future Work

Previous Work - Cyc Contains a “Building” constant, defined as “A specialization of both FixedStructure and HumanShelterConstruction.” By following assertions through the hierarchy, we can learn certain information about a building such as what rooms it contains, how many levels it has, etc. However, there is no structured presentation of how things are connected together, how the building is actually constructed.

Previous Work - IFC Data Model International standard for architectural firms, CAD developers, and construction companies. Very detailed information about building construction. However, also contains a great deal of information about processes, analysis, CAD data, etc. Also, it is inconsistently implemented.

Our Solution A language designed specifically to capture only the structure of a building. Encoded as an ontology in OWL DL, for ease of use with the Semantic Web, and (hopefully) full decidability on inference.

Language – General Classes Classes define different features of a Building. Four main classes Building External_Feature Internal_Feature Material Subclasses define distinct feature types.

Language - Properties Properties define relations between features. Most are defined symmetrically, for strong connectedness.

Language - Assertions Assertions enforce proper construction of buildings. Ensure that certain properties must be filled with some value (or possibly more than one value). There are no value restrictions.

Language - Specialization Language can be extended with subclasses of the general classes define to subtypes of each feature. e.g. House is a subtype of Building, Bedroom is a subtype of Room. Subtypes are defined by additional restrictions, some of which may be value restrictions. Subtypes can also be inferred, but this slows down search considerably.

Language - Limitations No spatial information (size, shape). No information about environment surrounding building. Some features are difficult to encode: Features serving multiple purposes (e.g. A roof also serving as a wall, such as in an A-frame). Features which are both external and internal.

Comparison with Current Technology Architectural FeatureHouseplans.com Our language # of Bedrooms/BathsYes # of FloorsYes Includes certain room typeYes Square footageYesNo Has X room on Y floorNoYes Has X room connected to Y roomNoYes # of exits from each roomNoYes

Other Applications Find paths out of buildings (fire escapes). Complete a building floor plan given a partial encoding of the building. Use a knowledge base encoded in this language to categorize buildings given partial information about them.

Future Work Adding spatial information without losing decidability. Adding encoding for surrounding environment and for objects within the building to create a full virtual world space. Encoding data automatically from floor plans or IFC models.

Conclusion Special thanks to Eyal for all his help and guidance. Questions / Comments ?