Provided is a tilt foot mechanism of a projection display device, in which the number of components is reduced to lower costs. It has a foot, a column adjoining the foot, and at least one cantilever arm, fastened to this column, for fastening the robot. A cluster is classified as datapath if both the support vector machine and the neural network indicate that it is datapath-like. the warm interior air, used as defrost air, may be able to circulate from the interior of the building into the ventilation apparatus and back to the interior of the building. Other inputs may include additional complex network and customer related business rules.