Stefano Bortoli

Decentralised social network management

Social networking sites have gained much popularity in the recent years because of the opportunities they give to people to connect to each other in an easy and timely manner, and to exchange and share various kinds of information. However, these sites are based on a centralised paradigm, which limits the mobility of their users, and ultimately, their chances to establish new relationships and benefit from diverse networking services. In this paper, we argue for a decentralised paradigm for social networking, in which users retain control of their profiles, and social networking sites focus on the delivery of innovative and competitive services. In this environment, both the social networking sites and their users will be able to develop to their full potential. This goal can be achieved by using a combination of semantic web technologies and tools, loosening the bind between the social network management and social networking web applications.

Can Persistent Identifiers Be Cool

The fast growth of scientific and non-scientific digital data, as well as the proliferation of new types of digital content, has led – among many other things – to a lot of innovative work on the concept of the identifier. Digital identifiers have become the key to preserving and accessing content, just as physical identifier tags have been the key to accessing paper-based content and other physical entities for millennia. Two main schools of thought have emerged: on the one hand, librarians and public repositories have pushed the concept of the Persistent Identifier (PI) as a way to guarantee long term identification and (sometimes) access; on the other hand, the extraordinary success of the web has led several researchers and web experts to push the concept of the Cool URI as the universal mechanism for identifying and accessing digital content. Both views have their pros and cons, but so far (with only a few exceptions) the two visions have developed in parallel, sometimes with a subtle underlying hostility. In this paper, we present the evolution of the Entity Name System (ENS), an open service-based platform developed as part of the OKKAM EU co-funded project, which can reconcile these two approaches. The new system, called ENS2.0, is currently under development and will enable data creators and curators to combine the technical strengths and opportunities of the (Semantic) Web vision with the organizational, economical and social requirements legitimately raised by the PI community and stakeholders.

An Identification Ontology for Entity Matching

In this context we present the Identification Ontology, as an application ontology for a knowledge-based solution to the entity matching problem in the context of the Semantic Web. The Identification Ontology has a threefold role: 1 represent a selection of attributes that are relevant for identification or entity matching of a set of entity types; 2 supporting the definition of a set of contextual ontological mappings to ease the problem of semantic heterogeneity affecting entity matching in the Semantic Web; and 3 represent meta-properties of the considered features to highlight their roles in the definition of a knowledge-based entity matching solution. The Identification Ontology taxonomy is defined refining and extending the Okkam Conceptual Model, as a top level ontology modeling the identity and reference domain. Furthermore, it defines also a set of top-level entity types and relative features relying on a methodology that combines results from cognitive studies and a survey of existing vocabularies available through Linked Open Vocabulary initiative. The Identification Ontology is currently used as part of the Okkam Entity Name System matching framework, which was successfully tested in entity matching experiments and used in large-scale industrial linkage tasks to enable data integration for applications dealing with tax assessment and credit risk analysis.

Semantic big data for tax assessment

Semantic Big Data is about the creation of new applications exploiting the richness and flexibility of declarative semantics combined with scalable and highly distributed data management systems. In this work, we present an application scenario in which a domain ontology, Open Refine and the Okkam Entity Name System enable a frictionless and scalable data integration process leading to a knowledge base for tax assessment. Further, we introduce the concept of Entiton as a flexible and efficient data model suitable for large scale data inference and analytic tasks. We successfully tested our data processing pipeline on a real world dataset, supporting ACI Informatica in the investigation for Vehicle Excise Duty (VED) evasion in Aosta Valley region (Italy). Besides useful business intelligence indicators, we implemented a distributed temporal inference engine to unveil VED evasion and circulation ban violations. The results of the integration are presented to the tax agents in a powerful Siren Solution KiBi dashboard, enabling seamless data exploration and business intelligence.

OntoCleaning the Okkam Conceptual Model

The way people define and use identifiers to refer to entities has been under philosophical investigation for a long time. This problem gained attention also in the context of the Semantic Web, where the Identity Crisis has threatened one of the cornerstones of the proposed vision: the unambiguous identification of Resources. In this paper we present the application of OntoClean as a formal methodology to formally validate the Okkam Conceptual Model that was proposed to address the problem of identity and reference. In performing such analysis, we unfold some of the philosophical problems affecting the representation of several types of real world entities, presenting a literature review and arguing in favor of some interpretation. This is done with the twofold purpose of contributing to the ongoing debate, and fostering the definition of a shared vision about the problem that will support further advancements in development of the Semantic Web vision. Furthermore, we argue in favor of the adoption of the Okkam IDs as globally persistent and rigid identifiers as a sound solution to the problem of the Identity and Reference in the context of the Semantic Web.