Navegación

Búsqueda

Búsqueda avanzada

El autor Xavier Oriol ha publicado 5 artículo(s):

2 - Practical Update Management in Ontology-based Data Access (YA PUBLICADO)

Ontology-based Data Access (OBDA) is gaining importance both scientifically and practically. However, little attention has been paid so far to the problem of updating OBDA systems. This is an essential issue if we want to be able to cope with modifications of data both at the ontology and at the source level, while maintaining the independence of the data sources. In this paper, we propose mechanisms to properly handle updates in this context. We show that updating data both at the ontology and source level is first-order rewritable. We also provide a practical implementation of such updating mechanisms based on non-recursive Datalog.

Autores: Giuseppe De Giacomo / Domenico Lembo / Xavier Oriol / Domenico Fabio Savo / Ernest Teniente / 
Palabras Clave: DL-Lite - OBDA - updates

3 -

4 - Linking Data and BPMN Processes to Achieve Executable Models (Summary)

Summary of the Contribution The two main assets of any organization are (i) information, i.e., data, which are the things that the organization knows about, and (ii) processes, which are collections of activities that describe how work is performed within an organiza- tion. Recent research has highlighted the importance of considering both process and data as key elements in process and service design. However, models that represent processes and data are typically developed by different teams, resulting in unrelated models which neglect the interaction between the two.
Bearing this in mind, in this paper we propose to connect processes and data, and a way to automatically execute the resulting model. To do so, we assume that processes are represented using BPMN and data in a UML class diagram.
In order to link both formalisms, we propose the following: (1) the creation of an Artifact, which represents a set of process variables associated to a certain process instance, and (2) the specification of the activities or tasks in the process, showing how they make changes to the data. We propose representing the artifact as an additional class in the UML class diagram. On the other hand, we opt for OCL operation contracts (with a pre and a postcondition) to specify details of the process activities. Note that other languages could be used to represent the data, the process and the contracts, as long as they have unambiguous semantics and whose expressiveness is equivalent to first-order logic.
Following this framework, we can then achieve executability of the frame- work, by relying on SQL technology. The UML class diagram is encoded as a relational database, the BPMN diagram can be formalized as a Petri net, and the OCL contracts can be encoded as logic rules from which SQL statements can be derived and applied to the database.
To prove the feasiblity of our approach, we have developed a prototype tool in Java which can load the models in our framework and execute the operations at runtime in a relational database.

Autores: Giuseppe De Giacomo / Xavier Oriol / Montserrat Estañol / 
Palabras Clave:

5 - An Ontology-based Framework for Describing Discoverable Data Services

Data-services are applications whose main concern is to provide data to theirclient applications. Data-services play a key role in areas like the Internet ofThings (IoT), where smart objects might want to offer/consume data throughInternet, and thus, providing/discovering such data-services automatically.To make data-services discoverable, the usual strategy is to register dataservicesin some kind of service-broker, i.e., a marketplace where data-services arepublicly offered. Then, smart objects query the service-broker, and the servicebroker is responsible to match the request with its data-services. How to perform this matching automatically is still an open problem in IoT.In this paper, we propose a framework for specifying data-services so thatthey can be automatically discovered. To achieve it, we provide unambiguousdescriptions of the data-services and the request, together with a mechanismcapable of interpreting these descriptions and check whether they match. Oursolution is grounded on ontology-based data integration and can be applied inthe IoT context, altought it can also be used in any other domain involving thediscovery of applications retrieving data.In essence, our idea is based on, given a domain ontology describing thereal world our data-services speaks about, consider each data-service as a newassociation in that ontology. Indeed, a data-service consuming some input objectsand retrieving some output objects can be modelled as an association from theproper to the latter. As expected, ontology constraints must be used to restrictthe instances of the association to the input-output instances our data-serviceexpects/provides.Hence, the problem of matching data-services is reduced to that of automaticreasoning on ontologies (and in particular, association subsumption). Thus, contributions on this last field can be directly used for the data-services discovering problem.

Autores: Xavier Oriol / Ernest Teniente / 
Palabras Clave: Data-service - Data-service discovery - Internet of Things