Papers by Giuseppe Giacomo
Workshops in Computing, 1993
We consider intensional answers to be logical formulas expressing sufficient conditions for objec... more We consider intensional answers to be logical formulas expressing sufficient conditions for objects to belong to the usual answer to a query addressed to a knowledge base. We show that in the SLDNF-resolution framework, complete and procedurally complete sets of intensional answers can be generated by using partial evaluation. Specific treatments of recursion and negation are also presented.
Artificial Intelligence, 1999
Like classical planning, the execution of high-level agent programs requires a reasoner to look a... more Like classical planning, the execution of high-level agent programs requires a reasoner to look all the way to a final goal state before even a single action can be taken in the world. This deferral is a serious problem in practice for large programs. Furthermore, the problem is ...
In this paper we study how automated reasoning systems based on Description Logics (DLs) can be u... more In this paper we study how automated reasoning systems based on Description Logics (DLs) can be used for reasoning about UML class di- agrams. The ability of reasoning automatically on UML class diagrams makes it possible to provide computer aided support during the appli- cation design phase in order to automatically detect relevant properties, such as inconsistencies and redundancies. We
Description Logics, 2003
Composition of e-Services is the issue of synthesizing a new composite e- Service, obtained by co... more Composition of e-Services is the issue of synthesizing a new composite e- Service, obtained by combining a set of available component e-Services, when a client request cannot be satised by available e-Services. In this paper we propose a general framework addressing the problem of e-Service composition. We then show that, under certain assumptions, composition can be realized through DL- based
Composition of e-Services is the issue of synthesizing a new composite e-Service, obtained by com... more Composition of e-Services is the issue of synthesizing a new composite e-Service, obtained by combining a set of available component e-Services, when a client request cannot be satis- fied by available e-Services. In this paper we study the prob- lem of composition synthesis in a general framework. We consider e-Services as arbitrary (possibly infinite) execution trees, i.e., as trees of
Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems - PODS '98, 1998
Abstract Query containment under constraints is the problem of checking whether for every databas... more Abstract Query containment under constraints is the problem of checking whether for every database satisfying a given set of constraints, the result of one query is a subset of the result of another query, Recent research points out that this is a central problem in severa database applications, and we address it within A setting where constraints are specified in the form of special inclusion dependencies over complex expressions, built by using intersection and difference of relations, special forms of quantification, regular expressions ...
Proceedings 3rd IFCIS International Conference on Cooperative Information Systems (Cat No 98EX122) COOPIS-98, 1998
Abstract Information integration is one of the core problems in cooperative information systems. ... more Abstract Information integration is one of the core problems in cooperative information systems. The authors argue that two critical factors for the design and maintenance of applications requiring information integration are conceptual modeling of the domain, and reasoning support over the conceptual representation. In particular they present a general architecture for information integration that explicitly includes a conceptual representation of the application. They illustrate how the architecture can express several integration ...
Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130), 1998
Abstract Source integration is one of the core problems in data warehousing. Two critical factors... more Abstract Source integration is one of the core problems in data warehousing. Two critical factors for the design and maintenance of applications requiring source integration, and in particular data warehouse applications, are conceptual modeling of the domain, and reasoning support over the conceptual representation. We present a novel approach to conceptual modeling for source integration, which allows for suitably modeling the global concepts of the application, the individual information sources, and the constraints among ...
In this paper we address the problem of query rewriting in the context of semi-structured data. W... more In this paper we address the problem of query rewriting in the context of semi-structured data. We present a method for computing the rewriting of a regular expression E in terms of other regular expressions. The method computes the exact rewriting (the one that defines the same regular language as E) if it exists, or the rewriting that defines the
Symposium on Principles of Database Systems, 2004
International Journal of Cooperative Information Systems, 2004
Description Logics, 2002
Abstract: In this paper we demonstrate that two-way alternating automata on infinite trees (2ATAs... more Abstract: In this paper we demonstrate that two-way alternating automata on infinite trees (2ATAs) provide a very elegant and effective formal tool for addressing reasoning in expressive DLs. Indeed, the encoding of a DL concept (to be checked for satisfiability) into an automaton (to be checked for non-emptiness) is: (i) intuitive, indeed, comparable to tableaux rules; (ii) modular, since each
National Conference on Artificial Intelligence, 2004
Reiter's variant of the Situation Calculus is tightly related to relational databases, when c... more Reiter's variant of the Situation Calculus is tightly related to relational databases, when complete information on the ini- tial situation is available. In particular, the information on the initial situation can be seen as a relational database, and actions, as specified by the preconditions and successor state axioms, can be seen as operations that change the state of the database.
Artificial Intelligence, 1999
Artificial Intelligence, 1999
International Joint Conference on Artificial Intelligence, 1997
As an alternative to planning, an approach to high- level agent control based on concurrent progr... more As an alternative to planning, an approach to high- level agent control based on concurrent program execution is considered. A formal definition in the situation calculus of such a programming language is presented and illustrated with a detailed exam ple. The language includes facilities for prioritizing the concurrent execution, interrupting the execution when certain conditions become true, and dealing with
Lecture Notes in Computer Science, 1996
This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse ba... more This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for mu-calculus. We prove the correctness and completeness of the calculus and illustrate its features. We also discuss the transformation of the tableaux method (naively NEXPTIME) into an EXPTIME algorithm.
Proceedings of the 32nd symposium on Principles of database systems - PODS '13, 2013
Data-centric dynamic systems are systems where both the process controlling the dynamics and the ... more Data-centric dynamic systems are systems where both the process controlling the dynamics and the manipulation of data are equally central. Recently such kinds of systems are increasingly attracting the interest of the scientific community, especially in their variant called artifact-centric business processes. In this paper we study verification of (first-order) µ-calculus variants over relational data-centric dynamic systems, where data are represented by a fullfledged relational database, and the process is described in terms of atomic actions that evolve the database. The execution of such actions may involve calls to external services, providing fresh data inserted into the system. As a result such systems are typically infinite-state. We show that verification is undecidable in general, and we isolate notable cases, where decidability is achieved. Specifically we start by considering service calls that return values deterministically (depending only on passed parameters). We show that in a µ-calculus variant that preserves knowledge of objects appeared along a run we get decidability under the assumption that the fresh data introduced along a run are bounded, though they might not be bounded in the overall system. In fact we tie such a result to a notion related to weak acyclicity studied in data exchange. Then, we move to nondeterministic services where the assumption of data bounded run would result in a bound on the service calls that can be invoked during the execution and hence would be too restrictive. So we investigate decidability under the assumption that knowledge of objects is preserved only if they are continuously present. We show that if infinitely many values occur in a run but do not accumulate in the same state, then we get again decidability. We give syntactic conditions to avoid this accumulation through the novel notion of "generate-recall acyclicity", which takes into consideration that every service call activation generates new values that cannot be accumulated indefinitely.
Lecture Notes in Computer Science, 1995
Prepositional Dynamic Logics (PDL's) provide a suitable formal framework for... more Prepositional Dynamic Logics (PDL's) provide a suitable formal framework for modeling actions and reasoning about them. However, the basic language of PDL's lack several features that are important for a sophisticated treatment of actions. In this paper, we present a new logic that is obtained by enriching the basic PDL with powerful modeling constructs that allow us to represent determinism and non-determinisms, concurrency, hierarchies, mutual exclusion, backward execution, and non-execution of actions. We demonstrate, by ...
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Papers by Giuseppe Giacomo