A memory system includes a number of integrated circuit chips coupled to a bus. A controller for controlling the at least one impeller motor in consideration of the ratio; and a sensor for sensing the inclination of the floor andor wall on which the robot is propelled are also provided. The apparatus can also include an adjustable depth bracket, wherein the adjustable depth bracket allows the enclosure to be secured against a back surface within the existing cabinet. For each pinnacle concept \u201cC,\u201d whose reference is to be determined, a set of linguistic features can be compiled that is referred to herein as a \u201cconcept feature set.