In a preferred embodiment, a modular desk includes a frame defining a periphery of a worksurface area and at least one opening formed within the worksurface area. Thus the present general inventive concept provides a display apparatus and a control method thereof, in which video signals are individually rotated, thereby providing an optimum picture to a user and realizing various screen displays. Video inputs are analyzed, with a plurality of independent automated decision-making systems each determining if an abnormal condition exists based upon the constructed profiles.