A Conceptual Framework for Object Composition and Behavior Description

Abstract:  this paper. The statement of the lift problem is: A lift system is to be installed in a building with m floors. The lift is only aimed at moving goods from one floor to another. Persons are not allowed to ride in this lift. Therefore, there are no control buttons inside a cab. The cab is allowed to support a given maximal load depending on the value of the counter weight and the power of the motor. A sensor determines if the allowed maximum load is not violated. If so, the sensor sends an overload signal (overload warning) to the lift control mechanism. It is assumed that the lift and the control mechanism are supplied by the manufacturer. The internal workings of the control mechanism are not of concern. The aspects to be described concern the usage of this lift by a clerk. The lift is used under the following constraints: 1. Each floor has buttons: floor selection buttons, door command buttons, and lift request buttons. These buttons illuminate when pressed. The illumination is canceled using the following rules: - for floor selection buttons, when the lift reaches the desired floor - for door command buttons, when the operation is completed - for lift request buttons, when a lift visits the floor and is either moving in the desired direction, or has no outstanding requests. In the latter case, if both floor request buttons are pressed, only one should be canceled. The algorithm to decide which to service first should minimize the waiting time for both requests. A Conceptual Framework for Object Composition and Behavior Description page 29 2. All requests for lifts from floors must be serviced eventually, with all floors given equal priority. Assumptions made for this problem are: - the cab has a fixed original volume which limits the quantity of goods which may be ...