An Empirical Investigation of Learning From the Semantic Web

Peer reviewed

Innovazione nel Semantic Web: Evoluzione della base di conoscenza semantica YAGO

La presente ricerca tratta lo studio delle basi di conoscenza, volto a facilitare la raccolta, l'organizzazione e la distribuzione della conoscenza. La scelta dell’oggetto è dovuta all'importanza sempre maggiore acquisita da questo ambito di ricerca e all'innovazione che esso è in grado di apportare nel campo del Web semantico. Viene analizzata la base di conoscenza YAGO: se ne descrivono lo stato dell’arte, le applicazioni e i progetti per sviluppi futuri. Il lavoro è stato condotto esaminando le pubblicazioni relative al tema e rappresenta una risorsa in lingua italiana sull'argomento.

On the application of contextual IoT service discovery in Information Centric Networks

The continuous flow of technological developments in communications and electronic industries has led to the growing expansion of the Internet of Things (IoT). By leveraging the capabilities of smart networked devices and integrating them into existing industrial, leisure and communication applications, the IoT is expected to positively impact both economy and society, reducing the gap between the physical and digital worlds. Therefore, several efforts have been dedicated to the development of networking solutions addressing the diversity of challenges associated with such a vision. In this context, the integration of Information Centric Networking (ICN) concepts into the core of IoT is a research area gaining momentum and involving both research and industry actors. The massive amount of heterogeneous devices, as well as the data they produce, is a significant challenge for a wide-scale adoption of the IoT. In this paper we propose a service discovery mechanism, based on Named Data Networking (NDN), that leverages the use of a semantic matching mechanism for achieving a flexible discovery process. The development of appropriate service discovery mechanisms enriched with semantic capabilities for understanding and processing context information is a key feature for turning raw data into useful knowledge and ensuring the interoperability among different devices and applications. We assessed the performance of our solution through the implementation and deployment of a proof-of-concept prototype. Obtained results illustrate the potential of integrating semantic and ICN mechanisms to enable a flexible service discovery in IoT scenarios.

Ontologies and the Semantic Web: Problems and Perspectives for LIS Professionals

Many years have passed since Berners-Lee envi- sioned the Web as it should be (1999), but still many information professionals do not know their precise role in its development, especially con- cerning ontologies –considered one of its main elements. Why? May it still be a lack of under- standing between the different academic commu- nities involved (namely, Computer Science, Lin- guistics and Library and Information Science), as reported by Soergel (1999)? The idea behind the Semantic Web is that of several technologies working together to get optimum information re- trieval performance, which is based on proper resource description in a machine-understandable way, by means of metadata and vocabularies (Greenberg, Sutton and Campbell, 2003). This is obviously something that Library and Information Science professionals can do very well, but, are we doing enough? When computer scientists put on stage the ontology paradigm they were asking for semantically richer vocabularies that could support logical inferences in artificial intelligence as a way to improve information retrieval systems. Which direction should vocabulary development take to contribute better to that common goal? The main objective of this paper is twofold: 1) to identify main trends, issues and problems con- cerning ontology research and 2) to identify pos- sible contributions from the Library and Information Science area to the development of ontologies for the semantic web. To do so, our paper has been structured in the following manner. First, the methodology followed in the paper is reported, which is based on a thorough literature review, where main contributions are analysed. Then, the paper presents a discussion of the main trends, issues and problems concerning ontology re- search identified in the literature review. Recom- mendations of possible contributions from the Library and Information Science area to the devel- opment of ontologies for the semantic web are finally presented.

Scheme Versioning in the Semantic Web

This paper describes a conceptual framework and meth- odology for managing scheme versioning for the Semantic Web. The first part of the paper introduces the concept of vocabulary encoding schemes, distinguished from metadata schemas, and discusses the characteristics of changes in schemes. The paper then presents a proposal to use a value record–similar to a term record in thesaurus management techniques–to manage scheme versioning challenges for the Semantic Web. The con-clusion identifies future research directions.

Representing image captions as concept graphs using semantic information

Conceptual interpretation of languages has gathered peak interest in the world of artificial intelligence. The challenge in modeling various complications involved in a language is the main motivation behind our work. Our main focus in this work is to develop conceptual graphical representation for image captions. We have used discourse representation structure to gain semantic information which is further modeled into a graphical structure. The effectiveness of the model is evaluated by a caption based image retrieval system. The image retrieval is performed by computing subgraph based similarity measures. Best retrievals were given an average rating of . ± . out of 4 by a group of 25 human judges. The experiments were performed on a subset of the SBU Captioned Photo Dataset. This purpose of this work is to establish the cognitive sensibility of the approach to caption representations

Representing image captions as concept graphs using semantic information

Conceptual interpretation of languages has gathered peak interest in the world of artificial intelligence. The challenge in modeling various complications involved in a language is the main motivation behind our work. Our main focus in this work is to develop conceptual graphical representation for image captions. We have used discourse representation structure to gain semantic information which is further modeled into a graphical structure. The effectiveness of the model is evaluated by a caption based image retrieval system. The image retrieval is performed by computing subgraph based similarity measures. Best retrievals were given an average rating of . ± . out of 4 by a group of 25 human judges. The experiments were performed on a subset of the SBU Captioned Photo Dataset. This purpose of this work is to establish the cognitive sensibility of the approach to caption representations.

RDF i Web Semàntica

En aquest treball s'explica el concepte de Web Semàntica, junt amb la seva estructura i els diferents termes relacionats amb aquesta idea. A més, es fa especial atenció al paper dels sistemes gestors de bases de dades en aquest camp, tenint en compte sobretot el nivell de compatibilitat que ofereixen aquests per a tracta dades en notació RDF, basada en el llenguatge XML.

BIRD-A: una piattaforma per la creazione di interfacce Web basate su ontologie per l'authoring di dati RDF

Lo scopo del progetto Bird-A è di mettere a disposizione uno strumento basato su ontologie per progettare un'interfaccia web collaborativa di creazione, visualizzazione, modifica e cancellazione di dati RDF e di fornirne una prima implementazione funzionante. La visione che sta muovendo la comunità del web semantico negli ultimi anni è quella di creare un Web basato su dati strutturati tra loro collegati, più che su documenti. Questo modello di architettura prende il nome di Linked Data ed è basata sulla possibilità di considerare cose, concetti, persone come risorse identificabili tramite URI e di poter fornire informazioni e descrivere collegamenti tra queste risorse attraverso l'uso di formati standard come RDF. Ciò che ha però frenato la diffusione di questi dati strutturati ed interconnessi sono stati gli alti requisiti di competenze tecniche necessarie sia alla loro creazione che alla loro fruizione. Il progetto Bird-A si prefigge di semplificare la creazione e la fruizione di dati RDF, favorendone la condivisione e la diffusione anche fra persone non dotate di conoscenze tecniche specifiche.

A Semantic Scraping Model for Web Resources - Applying Linked Data to Web Page Screen Scraping

In spite of the increasing presence of Semantic Web Facilities, only a limited amount of the available resources in the Internet provide a semantic access. Recent initiatives such as the emerging Linked Data Web are providing semantic access to available data by porting existing resources to the semantic web using different technologies, such as database-semantic mapping and scraping. Nevertheless, existing scraping solutions are based on ad-hoc solutions complemented with graphical interfaces for speeding up the scraper development. This article proposes a generic framework for web scraping based on semantic technologies. This framework is structured in three levels: scraping services, semantic scraping model and syntactic scraping. The first level provides an interface to generic applications or intelligent agents for gathering information from the web at a high level. The second level defines a semantic RDF model of the scraping process, in order to provide a declarative approach to the scraping task. Finally, the third level provides an implementation of the RDF scraping model for specific technologies. The work has been validated in a scenario that illustrates its application to mashup technologies

RDSZ: an approach for lossless RDF stream compression

In many applications (like social or sensor networks) the in- formation generated can be represented as a continuous stream of RDF items, where each item describes an application event (social network post, sensor measurement, etc). In this paper we focus on compressing RDF streams. In particular, we propose an approach for lossless RDF stream compression, named RDSZ (RDF Differential Stream compressor based on Zlib). This approach takes advantage of the structural similarities among items in a stream by combining a differential item encoding mechanism with the general purpose stream compressor Zlib. Empirical evaluation using several RDF stream datasets shows that this combi- nation produces gains in compression ratios with respect to using Zlib alone.

Efficient RDF Interchange (ERI) format for RDF data streams

RDF streams are sequences of timestamped RDF statements or graphs, which can be generated by several types of data sources (sensors, social networks, etc.). They may provide data at high volumes and rates, and be consumed by applications that require real-time responses. Hence it is important to publish and interchange them efficiently. In this paper, we exploit a key feature of RDF data streams, which is the regularity of their structure and data values, proposing a compressed, efficient RDF interchange (ERI) format, which can reduce the amount of data transmitted when processing RDF streams. Our experimental evaluation shows that our format produces state-of-the-art streaming compression, remaining efficient in performance.

Web semántica: RDF y SGBD que lo soportan

En aquest treball es fa una breu introducció a la web semàntica i el seu estat actual. S'analitzen els llenguatges que hi ha a la base del munt de recomanacions del World Wide Web Consortium (XML, XML Schema, RDF i RDF Schema) i s'examinen diferents sistemes de gestió de bases de dades que donen suport a les metadades, que són la base de la web semàntica.

Llenguatges de consulta per documents RDF

Els objectius principals d'aquest projecte són analitzar i descartar algunes dels llenguatges de consulta, gestors relacionals i reposadors que s'estan utilitzant més habitualment en l'entorn de la Web Semàntica. Amb l'estudi de les principals tecnologies implicades en la Web Semàntica es tractarà de realitzar una aplicació que permeti el maneig de dades d'un graf RDF.

Estudi dels llenguatges de consulta per a documents RDF

Aquest treball aporta una visió general de la Web Semàntica i alhora n'estudia en suficient detall les principals tecnologies relacionades. Com a objectiu final per comprovar de forma pràctica la teoria descrita, l'aplicació web permet consultar bases de dades RDF mitjançant el llenguatge de consulta SPARQL.