66,517 research outputs found
Efficient Monitoring of Parametric Context Free Patterns
Recent developments in runtime verification and monitoring show that parametric regular and temporal logic specifications can be efficiently monitored against large programs. However, these logics reduce to ordinary finite automata, limiting their expressivity. For example, neither can specify structured properties that refer to the call stack of the program. While context-free grammars (CFGs) are expressive and well-understood, existing techniques of monitoring CFGs generate massive runtime overhead in real-life applications. This paper shows for the first time that monitoring parametric CFGs is practical (on the order of 10% or lower for average cases, several times faster than the state-of-the-art). We present a monitor synthesis algorithm for CFGs based on an LR(1) parsing algorithm, modified with stack cloning to account for good prefix matching. In addition, a logic-independent mechanism is introduced to support partial matching, allowing patterns to be checked against fragments of execution traces
PLACES'10: The 3rd Workshop on Programmng Language Approaches to concurrency and Communication-Centric Software
Paphos, Cyprus. March 201
Alternating register automata on finite words and trees
We study alternating register automata on data words and data trees in
relation to logics. A data word (resp. data tree) is a word (resp. tree) whose
every position carries a label from a finite alphabet and a data value from an
infinite domain. We investigate one-way automata with alternating control over
data words or trees, with one register for storing data and comparing them for
equality. This is a continuation of the study started by Demri, Lazic and
Jurdzinski. From the standpoint of register automata models, this work aims at
two objectives: (1) simplifying the existent decidability proofs for the
emptiness problem for alternating register automata; and (2) exhibiting
decidable extensions for these models. From the logical perspective, we show
that (a) in the case of data words, satisfiability of LTL with one register and
quantification over data values is decidable; and (b) the satisfiability
problem for the so-called forward fragment of XPath on XML documents is
decidable, even in the presence of DTDs and even of key constraints. The
decidability is obtained through a reduction to the automata model introduced.
This fragment contains the child, descendant, next-sibling and
following-sibling axes, as well as data equality and inequality tests
A Categorical Framework for Quantum Theory
Underlying any theory of physics is a layer of conceptual frames. They
connect the mathematical structures used in theoretical models with physical
phenomena, but they also constitute our fundamental assumptions about reality.
Many of the discrepancies between quantum physics and classical physics
(including Maxwell's electrodynamics and relativity) can be traced back to
these categorical foundations. We argue that classical physics corresponds to
the factual aspects of reality and requires a categorical framework which
consists of four interdependent components: boolean logic, the
linear-sequential notion of time, the principle of sufficient reason, and the
dichotomy between observer and observed. None of these can be dropped without
affecting the others. However, in quantum theory the reduction postulate also
addresses the "status nascendi" of facts, i.e., their coming into being.
Therefore, quantum phyics requires a different conceptual framework which will
be elaborated in this article. It is shown that many of its components are
already present in the standard formalisms of quantum physics, but in most
cases they are highlighted not so much from a conceptual perspective but more
from their mathematical structures. The categorical frame underlying quantum
physics includes a profoundly different notion of time which encompasses a
crucial role for the present.Comment: 35 pages, 1 figur
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Using formal methods to support testing
Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent
years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing
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