Since the lifespan of each state is a real number more precisely, non-negative real or infinity, it is distinguished from discrete time systems, sequential machines, and Moore machines , in which time is determined by a tick time multiplied by non-negative integers.
Moreover, the lifespan can be a random variable ; for example the lifespan of a given state can be distributed exponentially or uniformly. The state transition and output functions of DEVS can also be stochastic. Zeigler proposed a hierarchical algorithm for DEVS model simulation in [Zeigler84] which was published in Simulation journal in DEVS defines system behavior as well as system structure.
Discrete Event Systems and Control / Ereignisdiskrete Systeme und Steuerungstheorie (DESC / ESS)
System behavior in DEVS formalism is described using input and output events as well as states. For example, for the ping-pong player of Fig. Each player, A , B , has its states: Send and Wait. Send state takes 0. The structure of ping-pong game is to connect two players: Player A 's output event!
The coupled DEVS defines which sub-components belong to it and how they are connected with each other. A coupled DEVS model is defined as an 8- tuple.
The ping-pong game of Fig. The simulation algorithm of DEVS models considers two issues: time synchronization and message propagation. Time synchronization of DEVS is to control all models to have the identical current time.
- FEUP - Discrete event systems!
- DEVS - Wikipedia?
- WODES: Workshop Series on Discrete Event Systems.
- Cell Culture Models of Biological Barriers: In vitro Test Systems for Drug Absorption and Delivery;
- Discrete Event Systems: Analysis and Control.
However, for an efficient execution, the algorithm makes the current time jump to the most urgent time when an event is scheduled to execute its internal state transition as well as its output generation. Message propagation is to transmit a triggering message which can be either an input or output event along the associated couplings which are defined in a coupled DEVS model. By introducing a quantization method which abstracts a continuous segment as a piecewise const segment, DEVS can simulate behaviors of continuous state systems which are described by networks of differential algebraic equations.
This research has been initiated by Zeigler in 90's  and many properties have been clarified by Prof.
Control of Discrete-Event Systems
Kofman in 's and Dr. In , Prof. Resources and References Web Pages:. The web page can be accessed through MyConcordia portal. Wonham and K.
Cassandras and S. Hopcroft and J. We will use DECK for the assignments and the project.
The project involves the design of a supervisory control system for the ozone generation system of a water treatment plant. The details will be announced later in class. All assignments and project reports must comply with the requirements of the " Expectations of Originality " form. This forms concerns the issue of academic integrity.