Rule-based natural-language interface for virtual environments

A hierarchical rule-based natural-language interface (NLI) for object-oriented virtual environment (VE) toolkits is described. The NLI allows modifying the properties of existing objects, as well as creating new objects in the VE using near-natural language speech. The rules are organized in a tree hierarchy with each rule branching to a 'group of rules'. Each tree-branch forms a possible user's command. Each rule generates global variables, which can be accessed by rules down the branch in order to formulate an appropriate action for the command. The action consists of a set of script commands that are sent to the VE. Also., the NLI maintains a state that allows it to respond to a command in the context of the previous command that the user issued. The hierarchical NLI exploits the object-oriented data structure of the VE toolkit by using three main levels of rules, namely, object, property, and action rules. The NLI can run on a remote computer and is linked to the computer running the VE via a network socket connection. The application of the NLI to the visualization of computational fluid dynamics results in a virtual wind tunnel is presented. Published by Elsevier Science Ltd.