Alessandro Mosca

Logic-based Reasoning Support for SBVR

Automated support to enterprise modeling has increasingly become a subject of interest for organizations seeking solutions for storage, distribution and analysis of knowledge about business processes. This interest has recently resulted in approving the standard for specifying Semantics of Business Vocabulary and Business Rules SBVR. Despite the existence of formally grounded notations, up to now SBVR still lacks a sound and consistent logical formalization which would allow developing automated solutions able to check the consistency of a set of business rules. This work reports on the attempt to provide logical foundations for SBVR by the means of defining a specific first-order deontic-alethic logic FODAL. The connections of FODAL with the modal logic QK and the description logic ALCQI have been investigated and, on top of the obtained theoretical results, a special tool providing automated support for consistency checks of a set of ALCQI-expressible deontic and alethic business rules has been implemented.

ORM2: Formalisation and Encoding in OWL2

This paper introduces ORM2 plus – a new linear syntax and complete semantics expressed in first order logic of ORM2 – which can be shown correctly embedding the original proposal. A provably correct encoding of the core fragment ORM2 zero in the \(\mathcal{ALCQI}\) description logic (a fragment of OWL2 with qualified cardinality restrictions and inverse roles) is presented. Complexity of reasoning on ORM2 conceptual schemas, and the ExpTime-membership of reasoning on ORM2 zero , are also shown. On the basis of these results, a systematic critique of alternative approaches to the formalisation of ORM2 in (description) logics published so far is provided. A prototype has been implemented providing a backend for the automated support of implicit constraints deduction, schema consistency checks, and user-defined constraints entailment, for ORM2 zero conceptual schemas along with its translation into \(\mathcal{ALCQI}\) knowledge bases.

Logic Foundations of the OCL Modelling Language

In this paper we define the first-order fragment of the Object Constraint Language (OCL), the declarative language for describing rules that apply to conceptual schemas in the Unified Modelling Language (UML). This fragment covers the whole of OCL without arithmetic operators, aggregation functions, iterators, and recursion. We give the set theoretical formal syntax and semantics in an elegant, concise, and clear way. This fragment has the same expressivity as domain-independent first-order logic (aka relational algebra), in the sense that any relational algebra expression can be reformulated as a logically equivalent OCL expression, and vice-versa.

Towards a Core ORM2 Language (Research Note)

The introduction of a provably correct encoding of a fragment of ORM2 (called ORM2 zero ) into a decidable fragment of OWL2, opened the doors for the definition of dedicated reasoning technologies supporting the quality of the schemas design. In this paper we discuss how to extend ORM2 zero in a maximal way by retaining at the same time the nice computational properties of ORM2 zero .

The Logic of Extensional RDFS

The normative version of RDF Schema (RDFS) gives non-standard (intensional) interpretations to some standard notions such as classes and properties, thus departing from standard set-based semantics. In this paper we develop a standard set-based (extensional) semantics for the RDFS vocabulary while preserving the simplicity and computational complexity of deduction of the intensional version. This result can positively impact current implementations, as reasoning in RDFS can be implemented following common set-based intuitions and be compatible with OWL extensions.

Knowledge Representation in EPNet

Semantic technologies are rapidly changing the historical research. This paper focuses on the knowledge representation and data modelling initiative that has characterised the first year of the EPNet project in the context of the historical research. The so-called EPNet CRM and Ontology are introduced here, and put in connection with existing modelling standards. The formal specification of the domain expert knowledge is the preliminary step toward the design of an innovative ‘Virtual Research Environment’ for scholars of the Roman Empire. Potential and actual benefits coming from the knowledge representation initiative are also discussed, with the main aim of encouraging experts in the humanities in embracing an innovative paradigm whose proved efficacy can positively affect their current research practices.

Non-monotonic Reasoning in Conceptual Modeling and Ontology Design: A Proposal

The Object Role Modeling language (ORM2) is nowadays the most widespread fact-based conceptual modeling language in the business world. Recently, it has been proposed an encoding of the core fragment of ORM2 (called ORM2zero) into the description logic \(\mathcal{ALCQI}\), allowing the use of reasoning technologies in the analysis of the schemas. A number of services has been defined there based on the FO semantics of ORM2. On the other hand, in many application domains there is a need for the formalization and modeling of defeasible information and non-monotonic reasoning services. Here we formalize a possible way of introducing non-monotonic reasoning into ORM2 schemas, enriching the language with special set of new constraints.

Semi-structured data extraction and modelling: the WIA Project

Over the last decades, the amount of data of all kinds available electronically has increased dramatically. Data are accessible through a range of interfaces including Web browsers, database query languages, application-specific interfaces, built on top of a number of different data exchange formats. All these data span from un-structured to highly structured data. Very often, some of them have structure even if the structure is implicit, and not as rigid or regular as that found in standard database systems. Spreadsheet documents are prototypical in this respect. Spreadsheets are the lightweight technology able to supply companies with easy to build business management and business intelligence applications, and business people largely adopt spreadsheets as smart vehicles for data files generation and sharing. Actually, the more spreadsheets grow in complexity (e.g., their use in product development plans and quoting), the more their arrangement, maintenance, and analysis appear as a knowledge-driven activity. The algorithmic approach to the problem of automatic data structure extraction from spreadsheet documents (i.e., grid-structured and free topological-related data) emerges from the WIA project: Worksheets Intelligent Analyser. The WIA-algorithm shows how to provide a description of spreadsheet contents in terms of higher level of abstractions or conceptualisations. In particular, the WIA-algorithm target is about the extraction of i) the calculus work-flow implemented in the spreadsheets formulas and ii) the logical role played by the data which take part into the calculus. The aim of the resulting conceptualisations is to provide spreadsheets with abstract representations useful for further model refinements and optimizations through evolutionary algorithms computations.