SMT-based Verification of LTL Specifications with Integer Constraints and its Application to Runtime Checking of Service Substitutability

An important problem that arises during the execution of service-based applications concerns the ability to determine whether a running service can be substituted with one with a different interface, for example if the former is no longer available. Standard Bounded Model Checking techniques can be used to perform this check, but they must be able to provide answers very quickly, lest the check hampers the operativeness of the application, instead of aiding it. The problem becomes even more complex when conversational services are considered, i.e., services that expose operations that have Input/Output data dependencies among them. In this paper we introduce a formal verification technique for an extension of Linear Temporal Logic that allows users to include in formulae constraints on integer variables. This technique applied to the substitutability problem for conversational services is shown to be considerably faster and with smaller memory footprint than existing ones

Constraint LTL Satisfiability Checking without Automata

This paper introduces a novel technique to decide the satisfiability of formulae written in the language of Linear Temporal Logic with Both future and past operators and atomic formulae belonging to constraint system D (CLTLB(D) for short). The technique is based on the concept of bounded satisfiability, and hinges on an encoding of CLTLB(D) formulae into QF-EUD, the theory of quantifier-free equality and uninterpreted functions combined with D. Similarly to standard LTL, where bounded model-checking and SAT-solvers can be used as an alternative to automata-theoretic approaches to model-checking, our approach allows users to solve the satisfiability problem for CLTLB(D) formulae through SMT-solving techniques, rather than by checking the emptiness of the language of a suitable automaton A_{\phi}. The technique is effective, and it has been implemented in our Zot formal verification tool.Comment: 39 page

Bounded Reachability for Temporal Logic over Constraint Systems

We present CLTLB(D), an extension of PLTLB (PLTL with both past and future operators) augmented with atomic formulae built over a constraint system D. Even for decidable constraint systems, satisfiability and Model Checking problem of such logic can be undecidable. We introduce suitable restrictions and assumptions that are shown to make the satisfiability problem for the extended logic decidable. Moreover for a large class of constraint systems we propose an encoding that realize an effective decision procedure for the Bounded Reachability problem

Geology of the Victoria quadrangle (H02), Mercury

Mercury’s quadrangle H02 ‘Victoria’ is located in the planet’s northern hemisphere and lies between latitudes 22.5° N and 65° N, and between longitudes 270° E and 360° E. This quadrangle covers 6.5% of the planet’s surface with a total area of almost 5 million km2. Our 1:3,000,000-scale geologic map of the quadrangle was produced by photo-interpretation of remotely sensed orbital images captured by the MESSENGER spacecraft. Geologic contacts were drawn between 1:300,000 and 1:600,000 mapping scale and constitute the boundaries of intercrater, intermediate and smooth plains units; in addition, three morpho-stratigraphic classes of craters larger than 20 km were mapped. The geologic map reveals that this area is dominated by Intercrater Plains encompassing some almost-coeval, probably younger, Intermediate Plains patches and interrupted to the north-west, north-east and east by the Calorian Northern Smooth Plains. This map represents the first complete geologic survey of the Victoria quadrangle at this scale, and an improvement of the existing 1:5,000,000 Mariner 10-based map, which covers only 36% of the quadrangle

Definability problems in Z and in Z_p

Le présent mémoire est dédié à l'étude des propriétés de définissabilité et, plus particulièrement, à la description des ensembles définissables dans de structures logiques qui s'interprètent naturellement dans la théorie des automates et à l'étude d'un problème de définissabilité de sous-structures. La thèse est divisée en deux parties principales : la première relative à l'étude de structures ayant pour domaine l'ensemble des entiers relatifs (et donc reliée aux langages sur des mots finis), la deuxième relative à l'étude de structures ayant pour domaine l'ensemble des entiers p-adiques (et donc reliée aux langages sur des mots infinis). La première partie étudie l'arithmétique de Presburger, c'est-à-dire l'arithmétique des entiers sans la multiplication. En donnant une caractérisation des ensembles définissable dans arithmétique faible de Presburger, nous prouvons la décidabilité de l'arithmétique faible de Presburger dans l'arithmétique de Presburger. La seconde partie de notre travail est par contre dédiée aux automates qui reconnaissent des mots infinis vus comme le codage de structures des donnes pour la manipulation de nombres. Contrairement à l'approche habituelle, nous considérerons les mots infinis comme le codage d'un entier p-adique. Nous prouverons que les ensembles d'entiers p- adiques reconnus par un automate de Buchi sont ceux exprimables au premier ordre dans une particulaire structure. Nous étudierons en outre la puissance expressive de quelques sous- structures, en établissant, quand cela est possible, une élimination des quantificateurs.PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Deciding whether the ordering is necessary in a Presburger formula

Automata, Logic and SemanticsWe characterize the relations which are first-order definable in the model of the group of integers with the constant 1. This allows us to show that given a relation defined by a first-order formula in this model enriched with the usual ordering, it is recursively decidable whether or not it is first-order definable without the ordering

New designs from circular nearrings

Nearrings are generalized rings in which addition is not in general abelian and only one distributive law holds. Some interesting combinatorial structures, as tactical configurations and balanced incomplete block designs (BIBDs) naturally arise when considering the class of planar and circular nearrings. We define the concept of disk and prove that in the case of field-generated planar circular nearrings it yields a BIBD. Such designs can be used in the construction of some classes of codes for which we are able to calculate the parameters. © 2013 Elsevier B.V