9 research outputs found
Effective Marking Equivalence Checking in Systems with Dynamic Process Creation
The starting point of this work is a framework allowing to model systems with
dynamic process creation, equipped with a procedure to detect symmetric
executions (ie., which differ only by the identities of processes). This allows
to reduce the state space, potentially to an exponentially smaller size, and,
because process identifiers are never reused, this also allows to reduce to
finite size some infinite state spaces. However, in this approach, the
procedure to detect symmetries does not allow for computationally efficient
algorithms, mainly because each newly computed state has to be compared with
every already reached state.
In this paper, we propose a new approach to detect symmetries in this
framework that will solve this problem, thus enabling for efficient algorithms.
We formalise a canonical representation of states and identify a sufficient
condition on the analysed model that guarantees that every symmetry can be
detected. For the models that do not fall into this category, our approach is
still correct but does not guarantee a maximal reduction of state space.Comment: In Proceedings Infinity 2012, arXiv:1302.310
Model Checking Contest @ Petri Nets, Report on the 2013 edition
This document presents the results of the Model Checking Contest held at
Petri Nets 2013 in Milano. This contest aimed at a fair and experimental
evaluation of the performances of model checking techniques applied to Petri
nets. This is the third edition after two successful editions in 2011 and 2012.
The participating tools were compared on several examinations (state space
generation and evaluation of several types of formul{\ae} -- reachability, LTL,
CTL for various classes of atomic propositions) run on a set of common models
(Place/Transition and Symmetric Petri nets).
After a short overview of the contest, this paper provides the raw results
from the contest, model per model and examination per examination. An HTML
version of this report is also provided (http://mcc.lip6.fr).Comment: one main report (422 pages) and two annexes (1386 and 1740 pages
Stark Spectroscopy and Radiative Lifetimes in Single Self-Assembled CdTe Quantum Dots
We present studies on Coulomb interactions in single self-assembled CdTe
quantum dots. We use a field effect structure to tune the charge state of the
dot and investigate the impact of the charge state on carrier wave functions.
The analysis of the quantum confined Stark shifts of four excitonic complexes
allows us to conclude that the hole wave function is softer than electron wave
function, i. e. it is subject to stronger modifications upon changing of the
dot charge state. These conclusions are corroborated by time-resolved
photoluminescence studies of recombination lifetimes of different excitonic
complexes. We find that the lifetimes are notably shorter than expected for
strong confinement and result from a relatively shallow potential in the
valence band. This weak confinement facilitates strong hole wave function
redistributions. We analyze spectroscopic shifts of the observed excitonic
complexes and find the same sequence of transitions for all studied dots. We
conclude that the universality of spectroscopic shifts is due to the role of
Coulomb correlations stemming from strong configuration mixing in the valence
band.Comment: sent to Physical Review
A high-level petri net-based formal model of distributed self-adaptive systems
Engineering complex distributed self-adaptive systems is a challenging task due to multiple interacting distributed components that monitor and adapt the managed parts operating in a dynamic environment. Therefore, formal methods able to specify and analyze the behavior of decentralized adaptation control by multiple interacting MAPE-K (Monitor, Analyze, Plan, and Execute over a shared Knowledge) components are highly demanded. In this paper we introduce a formal framework for modeling and analyzing self-adaptive systems with decentralized adaptation control. The framework makes use of High-Level Petri nets which represents a sound and expressive formal model for distributed discrete-event systems. We show how to specify in a natural way structural changes that are likely to occur in adaptable and evolvable distributed applications. Our approach supports validation and verification activities to check correctness of the MAPE components. As a proof-of-concepts, we show how to use our framework to model and analyze a self-optimizing cluster management system