Abstract: A method of assessing cognitive impairment of a user includes presenting a visual test stimulus to the user for a pre-determined test stimulus exposure duration. The test stimulus is then masked and a response from the user is measured. The response provides information about the user's perception of a characteristic of the test stimulus together with the time taken for the user to respond. These steps are repeated to develop a user profile and cognitive impairment in the user is assessed by comparing the user profile with a reference profile. A method of assessing cognitive impairment of a user includes presenting a visual test stimulus to the user for a pre-determined test stimulus exposure duration. The test stimulus is then masked and a response from the user is measured. The response provides information about the user's perception of a characteristic of the test stimulus together with the time taken for the user to respond.

Abstract: A method and apparatus that keeps information on all entities that are created when a model is built in a CAD system, including an indication of which command causes each entity to be added to or taken from the model. From this information, the system can determine the state of the model at any given time during its creation, without having to regenerate commands that generated the model at the determined state. For each new command, only those entities that are newly created are added to the database. The entities each have a version field that allows the same data to relate to different versions of the model.

Abstract: A cursor is dynamically attached to a two-dimensional representation of a three-dimensional surface in a CAD system. The system maps input coordinates indicating an initial position and a final position of a cursor to coordinates of a u-v surface representation of a the three-dimensional surface. The u-v coordinates are then mapped to display coordinates. The option to display this cursor on the surface is made by entering a command and by selecting a surface. The cursor preferably includes vectors indicating the magnitude and direction of the slope, and the display includes a window for displaying the u-v representation of the surface. A user can pick points on the surface based on what is visually observed on the display without projecting the point to another surface.