57,334 research outputs found
Entropy rate calculations of algebraic measures
Let . We use a special class of translation invariant
measures on called algebraic measures to study the entropy rate
of a hidden Markov processes. Under some irreducibility assumptions of the
Markov transition matrix we derive exact formulas for the entropy rate of a
general state hidden Markov process derived from a Markov source corrupted
by a specific noise model. We obtain upper bounds on the error when using an
approximation to the formulas and numerically compute the entropy rates of two
and three state hidden Markov models
Echos of the liquid-gas phase transition in multifragmentation
A general discussion is made concerning the ways in which one can get
signatures about a possible liquid-gas phase transition in nuclear matter.
Microcanonical temperature, heat capacity and second order derivative of the
entropy versus energy formulas have been deduced in a general case. These
formulas are {\em exact}, simply applicable and do not depend on any model
assumption. Therefore, they are suitable to be applied on experimental data.
The formulas are tested in various situations. It is evidenced that when the
freeze-out constraint is of fluctuating volume type the deduced (heat capacity
and second order derivative of the entropy versus energy) formulas will prompt
the spinodal region through specific signals. Finally, the same microcanonical
formulas are deduced for the case when an incomplete number of fragments per
event are available. These formulas could overcome the freeze-out backtracking
deficiencies.Comment: accepted to Nuclear Physics
The impact of Entropy and Solution Density on selected SAT heuristics
In a recent article [Oh'15], Oh examined the impact of various key heuristics
(e.g., deletion strategy, restart policy, decay factor, database reduction) in
competitive SAT solvers. His key findings are that their expected success
depends on whether the input formula is satisfiable or not. To further
investigate these findings, we focused on two properties of satisfiable
formulas: the entropy of the formula, which approximates the freedom we have in
assigning the variables, and the solution density, which is the number of
solutions divided by the search space. We found that both predict better the
effect of these heuristics, and that satisfiable formulas with small entropy
`behave' similarly to unsatisfiable formulas
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