IQAROS (Incremental Query Answering and Rewriting for OntologieS)
IQAROS is a prototypical query rewriting system that is based on incremental query rewriting. Given an ontology (in DL-Lite) and a Conjunctive query IQAROS can create a rewriting that is a Union of Conjunctive Queries.
The motivation for creating IQAROS was the theoretical study of query rewriting under query extensions. More precisely given a query and a rewriting for it we studied how to compute the rewriting of the query that was produced by the extension of the initial one with an atom. Interestingly the techniques that we developed for rewriting extended queries imply a novel approach for computing a rewriting for fixed queries. More precisely, given a (fixed) query we where able to pick one of its atoms compute a rewriting for it and then iteratively add the rest of the atoms by extending the previously computed rewriting. When all the atoms of the input query have been processed a rewriting for that query would have been computed.
Relevant Publications
- Tassos Venetis, Giorgos Stoilos, Giorgos B. Stamou:
Query Extensions and Incremental Query Rewriting for OWL 2 QL Ontologies. J. Data Semantics 3(1): 1-23 (2014) - Tassos Venetis, Giorgos Stoilos, Giorgos B. Stamou:
Incremental Query Rewriting for OWL 2 QL. Description Logics 2012 - Tassos Venetis, Giorgos Stoilos, Giorgos Β. Stamou:
Query Rewriting Under Query Extensions for OWL 2 QL Ontologies. SSWS 2011: 59-74
Project page
https://code.google.com/archive/p/iqaros/
MINT (Metadata INTeroperability services)
MINT services compose a web based platform that has been designed and developed to facilitate aggregation initiatives for cultural heritage content and metadata in Europe. It is employed from the first steps of such workflows, corresponding to the ingestion, mapping and aggregation of metadata records, and proceeds to implement a variety of remediation approaches for the resulting repository. The platform offers a user and organisation management system that allows the deployment and operation of different aggregation schemes (thematic or cross-domain, international, national or regional) and corresponding access rights. Registered organisations can upload (HTTP, FTP, OAI-PMH) their metadata records in XML or CSV serialization in order to manage, aggregate and publish their collections.
A reference metadata model serves as the aggregation schema to which the ingested (standard or proprietary) schemata are aligned to. Users can define their metadata crosswalks with the help of a visual mappings editor for the XSL language. Mapping is performed with simple drag-and-drop or input operations which are then translated to the corresponding code. The mappings editor visualises both the input and target XSD, in an intuitive interface that provides access and navigation of the structure and data of the input schema, and the structure, documentation and restrictions of the target one. It supports string manipulation functions for input elements in order to perform 1-N and M-1 (with the option between concatenation and element repetition) mappings between the two models. Additionally, structural element mappings are allowed, as well as constant or controlled value (target schema enumerations) assignment, conditional mappings (with a complex condition editor) and value mappings between input and target value lists. Mappings can be applied to ingested records, edited, downloaded and shared as templates between users of the platform.
Preview interfaces present to users the steps of the aggregation, including the current input XML record, the XSLT of the mappings, the transformed record in the target schema, subsequent transformations from the target schema to other models of interest (e.g. Europeana's metadata schema), and available HTML renderings of each XML record. Users can transform their selected collections using complete and validated mappings in order to publish them in available target schemas for the required aggregation and remediation steps.
The platform has been deployed for a variety of aggregation workflows and has served as aggregator of the Athena, Athena Plus, Carare, EUscreen, EUscreenXL, Europeana Fashion, DM2E, Linked Heritage, LoCloud, Europeana Sounds, Europeana Photography projects.
Link
http://mint-projects.image.ece.ntua.gr/mint4allRapid
Rapid is an efficient conjunctive query rewriting tool over Description Logic ontologies. It supports DL-Lite_R, ELHI and Horn-SHIQ ontologies. The input is an ontology expressed in OWL2 with the appropriate expressivity and a conjunctive query. In the case of DL-Lite_R input, the output rewriting is a union of conjunctive queries (UCQ), while in the case of ELHI and Horn-SHIQ ontologies the output is a Datalog program. Rapid uses several theoretical and implementational optimisation to deliver fast query rewriting for the supported expressivities. Its theoretical foundation and comparative evaluations against other similar systems have been published in several papers. It is implemented in Java.
Relevant Publications
- Despoina Trivela, Giorgos Stoilos, Alexandros Chortaras, Giorgos B. Stamou:
Optimising resolution-based rewriting algorithms for OWL ontologies. J. Web Sem. 33: 30-49 (2015) - Despoina Trivela, Giorgos Stoilos, Alexandros Chortaras, Giorgos B. Stamou:
Query Rewriting in Horn-SHIQ. Description Logics 2015 - Despoina Trivela, Giorgos Stoilos, Alexandros Chortaras, Giorgos B. Stamou:
Optimising Resolution-Based Rewriting Algorithms for DL Ontologies. Description Logics 2013: 464-476 - Alexandros Chortaras, Despoina Trivela, Giorgos B. Stamou:
Optimised Query Rewriting for OWL 2 QL. CADE 2011: 192-206 - Alexandros Chortaras, Despoina Trivela, Giorgos B. Stamou:
Goal-oriented Query Rewriting for OWL 2 QL. Description Logics 2011
Download
http://www.image.ece.ntua.gr/~achort/rapid/rapid.zipLicence
GNU General Public License
WITH
WITH is a platform that provides access to digital cultural heritage items from different repositories and offers a number of added-value services for the creative reuse and intelligent exploitation of that content.
The platform mashups APIs from different providers (such as Europeana, the Digital Public Library of America, Rijksmuseum, the British Library, YouTube etc) and accommodates for federated and faceted search functionalities. WITH enables users to aggregate and organise different types of cultural resources collected from external resources or uploaded by themselves; create their own exhibitions and tell their stories using an interface that provides for many custom features and presentation views; share their creations with other users or user groups; semantically enrich and annotate cultural content and other. Moreover, the WITH thematic space editor enables cultural institutions and other stakeholders to design and host custom web spaces in order to promote their organisation and engage users.
Link
http://withculture.eu
WITHcrowd
Το WITHcrowd αποτελεί επέκταση της πλατφόρμας WITH και προσφέρει υπηρεσίες πληθοπορισμού, οι οποίες παρέχουν τη δυνατότητα συλλογής πληροφοριών και μεταδεδομένων, μέσω εξωτερικής ανάθεσης εργασιών στο ευρύ κοινό, με στόχο τον εμπλουτισμό και την ανάδειξη του ψηφιακού πολιτιστικού περιεχομένου διαφόρων φορέων.
Το WITHcrowd παρέχει τη δυνατότητα σε μια ομάδα να ξεκινήσει μια πληθοποριστική εκστρατεία ως μια δράση δημιουργίας επισημειώσεων (με λέξεις-κλειδιά, χρωματικές ετικέτες ή γεοχωρική πληροφορία) για μια συγκεκριμένη συλλογή από το κοινό. Κάθε εκστρατεία έχει καθορισμένη χρονική διάρκεια και έναν στόχο επιθυμητού πλήθους επισημειώσεων. Το WITHcrowd προσφέρει πληροφορίες και στατιστικά που αφορούν την εξέλιξή κάθε εκστρατείας, όπως την ποσοστιαία πρόοδο με βάση το στόχο που έχει τεθεί, το πλήθος και έναν χάρτη με τις τοποθεσίες των χρηστών, και μια λίστα των πιο ενεργών χρηστών.
Οι χρήστες του WITHcrowd μπορούν να συνεισφέρουν σε οποιαδήποτε από τις τρέχουσες εκστρατείες μέσω μιας απλής και εύχρηστης διεπαφής, χωρίς να απαιτείται ειδικός χρόνος εκμάθησης της πλατφόρμας, ούτε εξειδικευμένες γνώσεις στο αντικείμενο που αφορά η εκστρατεία. Κάθε χρήστης μπορεί να δει στατιστικά της συνεισφοράς του σε κάθε εκστρατεία, όπως το πλήθος των επισημειώσεων που έχει δημιουργήσει, το πλήθος των αντικειμένων που έχει επισημάνει και την κατάταξή του στη λίστα των πιο ενεργών χρηστών σύμφωνα με τους βαθμούς που έχει συγκεντρώσει για τη συνεισφορά του. Το σύνολο των βαθμών κάθε χρήστη, καθορίζει και το έπαθλο που κερδίζει για τη συνεισφορά του στην εκστρατεία.