TY - GEN
AU - Nicholas Barton
AU - Goldman, Nick G
ID - 4306
T2 - Nature
TI - Genetics and geography
VL - 357
ER -
TY - CHAP
AU - Nicholas Barton
ED - Stenseth, Nils C
ED - Lidicker, William Z
ID - 4307
T2 - Animal dispersal: small mammals as a model
TI - The genetic consequences of dispersal
ER -
TY - JOUR
AU - Nicholas Barton
ID - 4308
IS - 2
JF - Evolution; International Journal of Organic Evolution
TI - On the spread of new gene combinations in the third phase of Wright's shifting balance
VL - 46
ER -
TY - CONF
AU - Thomas Henzinger
AU - Manna, Zohar
AU - Pnueli,Amir
ID - 4504
TI - What good are digital clocks?
VL - 623
ER -
TY - CONF
AB - We describe finite-state programs over real-numbered time in a guarded-command language with real-valued clocks or, equivalently, as finite automata with real-valued clocks. Model checking answers the question which states of a real-time program satisfy a branching-time specification (given in an extension of CTL with clock variables). We develop an algorithm that computes this set of states symbolically as a fixpoint of a functional on state predicates, without constructing the state space.
For this purpose, we introduce a mu-calculus on computation trees over real-numbered time. Unfortunately, many standard program properties, such as response for all nonzeno execution sequences (during which time diverges), cannot be characterized by fixpoints: we show that the expressiveness of the timed mu-calculus is incomparable to the expressiveness of timed CTL. Fortunately, this result does not impair the symbolic verification of "implementable" real-time programs--those whose safety constraints are machine-closed with respect to diverging time and whose fairness constraints are restricted to finite upper bounds on clock values. All timed CTL properties of such programs are shown to be computable as finitely approximable fixpoints in a simple decidable theory.
AU - Thomas Henzinger
AU - Nicollin, Xavier
AU - Sifakis, Joseph
AU - Yovine, Sergio
ID - 4505
TI - Symbolic model checking for real-time systems
ER -