Abstract: Embodiments provide methods, devices, and programs that simulate a teacher who teaches a complex program system to a student in private lessons. Embodiments may further provide customized feedback and reinforcement to students. Teaching units and action trees for learning are also discussed.

Abstract: A door closer assembly and a method for operating a door closer assembly. The door closer assembly includes a housing and a door piston guided in the housing. The door piston is operably connected to move a door. A spring piston is guided in the housing and is operable to assist movement of the door piston toward a door closing position. The spring piston is situated in the housing and is acted upon by a spring. The door closer assembly also includes a hydraulic control circuit containing hydraulic fluid which is operable to selectively eliminate a coupling of the door piston and the spring piston from one another during a portion of the travel path of the door piston in the housing. The door closer of the present invention improves the comfort of passing through a door by providing different transmission ratios and therefore, different moment curves.

Abstract: A hydraulic servo door closer in which the fixed coupling between the energy storage mechanism and the door piston has been neutralized. The fixed coupling is neutralized by the use of spring pistons which are pressurized by the closing spring, in addition to the door pistons which are conventionally present. The additional pressure chambers which are thereby formed, compared to a conventional door closer, are connected to one another on one hand by fixed channels, but on the other hand by controlled channels and/or throttles for the damping medium which is present in the door closer.