History
FD-DEVS was originally named as ``Schedule-Controlable DEVS`` and designed to support verification analysis of its networks which had been an open problem of DEVS formalism for 30 years. In addition, it was also designated to resolve the so-called ``OPNA`` problem of SP-DEVS. From the viewpoint of Classic DEVS, FD-DEVS has three restrictions
- finiteness of event sets and state set,
- the lifespan of a state can be scheduled by a rational number or infinity, and
- the internal schedule can be either preserved or updated by an input event.
The third restriction can be also seen as a relaxation from SP-DEVS where the schedule is always preserved by any input events. Due to this relaxation there is no longer OPNA problem, but there is also one limitation that a time-line abstraction which can be used for abstracting elapsed times of SP-DEVS networks is no longer useful for FD-DEVS network . But another time abstraction method which was invented by Prof. D. Dill can be applicable to obtain a finite-vertex reachability graph for FD-DEVS networks.
Read more about this topic: Finite & Deterministic Discrete Event System Specification
Famous quotes containing the word history:
“The principal office of history I take to be this: to prevent virtuous actions from being forgotten, and that evil words and deeds should fear an infamous reputation with posterity.”
—Tacitus (c. 55–c. 120)
“Regarding History as the slaughter-bench at which the happiness of peoples, the wisdom of States, and the virtue of individuals have been victimized—the question involuntarily arises—to what principle, to what final aim these enormous sacrifices have been offered.”
—Georg Wilhelm Friedrich Hegel (1770–1831)
“The history is always the same the product is always different and the history interests more than the product. More, that is, more. Yes. But if the product was not different the history which is the same would not be more interesting.”
—Gertrude Stein (1874–1946)