Abstract-Repairing an inconsistent knowledge base is a wellknown problem for which several solutions have been proposed and implemented in the past. In this paper, we start by looking at databases with active integrity constraints -consistency requirements that also indicate how the database should be updated when they are not met -as introduced by Caroprese et al. We show that the different kinds of repairs considered by those authors can be effectively computed by searching for leaves of specific kinds of trees. Although these computations are in general not very efficient (deciding the existence of a repair for a given database with active integrity constraints is N P -complete), on average the algorithms we present make significant reductions on the number of nodes in the search tree. Finally, these algorithms also give an operational characterization of different kinds of repairs that can be used when we extend the concept of active integrity constraints to the more general setting of knowledge bases.

Abstract. We present and evaluate an approach for the run-time conformance checking of Java classes against property-driven algebraic specifications. Our proposal consists in determining, at run-time, whether the classes subject to analysis behave as required by the specification. The key idea is to reduce the conformance checking problem to the runtime monitoring of contract-annotated classes, a process supported today by several runtime assertion-checking tools. Our approach comprises a rather conventional specification language, a simple language to map specifications into Java types, and a method to automatically generate monitorable classes from specifications, allowing for a simple, but effective, runtime monitoring of both the specified classes and their clients.

Integrity constraints in databases have been studied extensively since the 1980s, and they are considered essential to guarantee database integrity. In recent years, several authors have studied how the same notion can be adapted to reasoning frameworks, in such a way that they achieve the purpose of guaranteeing a system's consistency, but are kept separate from the reasoning mechanisms. In this paper we focus on multi-context systems, a general-purpose framework for combining heterogeneous reasoning systems, enhancing them with a notion of integrity constraints that generalizes the corresponding concept in the database world.Comment: FoIKS 201

Abstract:Consistency of knowledge repositories is of prime importance in organization management. Integrity constraints are a well-known vehicle for specifying data consistency requirements in knowledge bases; in particular, active integrity constraints go one step further, allowing the specification of preferred ways to overcome inconsistent situations in the context of database management. This paper describes a tool to validate an SQL database with respect to a given set of active integrity constraints, proposing possible repairs in case the database is inconsistent. The tool is able to work with the different kinds of repairs proposed in the literature, namely simple, founded, well-founded and justified repairs. It also implements strategies for parallelizing the search for them, allowing the user both to compute partitions of independent or stratified active integrity constraints, and to apply these partitions to find repairs of inconsistent databases efficiently in parallel.

Abstract. Although generics became quite popular in mainstream objectoriented languages and several specification languages exist that support the description of generic components, conformance relations between object-oriented programs and formal specifications that have been established so far do not address genericity. In this paper we propose a notion of refinement mapping that allows to define correspondences between parameterized specifications and generic Java classes. Based on such mappings, we put forward a conformance notion useful for the extension of CONGU, a tool-based approach we have been developing to support runtime conformance checking of Java programs against algebraic specifications, so that it becomes applicable to a more comprehensive range of situations, namely those that appear in the context of a typical Algorithms and Data Structures course.