24 research outputs found
MONAA: A Tool for Timed Pattern Matching with Automata-Based Acceleration
We present monaa, a monitoring tool over a real-time property specified by
either a timed automaton or a timed regular expression. It implements a timed
pattern matching algorithm that combines 1) features suited for online
monitoring, and 2) acceleration by automata-based skipping. Our experiments
demonstrate monaa's performance advantage, especially in online usage.Comment: Published in: 2018 IEEE Workshop on Monitoring and Testing of
Cyber-Physical Systems (MT-CPS
On the Verification of a WiMax Design Using Symbolic Simulation
In top-down multi-level design methodologies, design descriptions at higher
levels of abstraction are incrementally refined to the final realizations.
Simulation based techniques have traditionally been used to verify that such
model refinements do not change the design functionality. Unfortunately, with
computer simulations it is not possible to completely check that a design
transformation is correct in a reasonable amount of time, as the number of test
patterns required to do so increase exponentially with the number of system
state variables. In this paper, we propose a methodology for the verification
of conformance of models generated at higher levels of abstraction in the
design process to the design specifications. We model the system behavior using
sequence of recurrence equations. We then use symbolic simulation together with
equivalence checking and property checking techniques for design verification.
Using our proposed method, we have verified the equivalence of three WiMax
system models at different levels of design abstraction, and the correctness of
various system properties on those models. Our symbolic modeling and
verification experiments show that the proposed verification methodology
provides performance advantage over its numerical counterpart.Comment: In Proceedings SCSS 2012, arXiv:1307.802
Efficient exact pattern-matching in proteomic sequences
This paper proposes a novel algorithm for complete exact pattern-matching focusing the specificities of protein sequences (alphabet of 20 symbols) but, also highly efficient considering larger alphabets. The searching strategy uses large search windows allowing multiple alignments per iteration. A new filtering heuristic, named compatibility rule, contributed decisively to the efficiency improvement. The new algorithm’s performance is, on average, superior in comparison with its best-rated competitors
Métodos eficientes para a detecção de padrões exactos (pattern-matching) em sequências biológicas
Os algoritmos de detecção de padrões (pattern-matching), sejam exactos ou aproximados, são fundamentais na maioria das aplicações orientadas à análise de sequências biológicas. Nesta comunicação apresenta-se um novo algoritmo, denominado DC, desenvolvido para a especificidade do pattern-matching exacto, bem como uma análise comparativa do seu desempenho. Conclui-se que o desempenho do novo algoritmo supera, em média, o dos seus concorrentes, atribuindo-se o ganho de eficiência, sobretudo, à introdução de uma nova regra de filtragem denominada regra de compatibilidade
Designing optimal- and fast-on-average pattern matching algorithms
Given a pattern and a text , the speed of a pattern matching algorithm
over with regard to , is the ratio of the length of to the number of
text accesses performed to search into . We first propose a general
method for computing the limit of the expected speed of pattern matching
algorithms, with regard to , over iid texts. Next, we show how to determine
the greatest speed which can be achieved among a large class of algorithms,
altogether with an algorithm running this speed. Since the complexity of this
determination make it impossible to deal with patterns of length greater than
4, we propose a polynomial heuristic. Finally, our approaches are compared with
9 pre-existing pattern matching algorithms from both a theoretical and a
practical point of view, i.e. both in terms of limit expected speed on iid
texts, and in terms of observed average speed on real data. In all cases, the
pre-existing algorithms are outperformed
Efficient Online Timed Pattern Matching by Automata-Based Skipping
The timed pattern matching problem is an actively studied topic because of
its relevance in monitoring of real-time systems. There one is given a log
and a specification (given by a timed word and a timed automaton
in this paper), and one wishes to return the set of intervals for which the log
, when restricted to the interval, satisfies the specification
. In our previous work we presented an efficient timed pattern
matching algorithm: it adopts a skipping mechanism inspired by the classic
Boyer--Moore (BM) string matching algorithm. In this work we tackle the problem
of online timed pattern matching, towards embedded applications where it is
vital to process a vast amount of incoming data in a timely manner.
Specifically, we start with the Franek-Jennings-Smyth (FJS) string matching
algorithm---a recent variant of the BM algorithm---and extend it to timed
pattern matching. Our experiments indicate the efficiency of our FJS-type
algorithm in online and offline timed pattern matching
An adaptive hybrid pattern-matching algorithm on indeterminate strings
We describe a hybrid pattern-matching algorithm that works on both regular and indeterminate strings. This algorithm is inspired by the recently proposed hybrid algorithm FJS and its indeterminate successor. However, as discussed in this paper, because of the special properties of indeterminate strings, it is not straightforward to directly migrate FJS to an indeterminate version. Our new algorithm combines two fast pattern-matching algorithms, ShiftAnd and BMS (the Sunday variant of the Boyer-Moore algorithm), and is highly adaptive to the nature of the text being processed. It avoids using the border array, therefore avoids some of the cases that are awkward for indeterminate strings. Although not always the fastest in individual test cases, our new algorithm is superior in overall performance to its two component algorithms — perhaps a general advantage of hybrid algorithms