The Semantic Web 10

As the technology associated to the ?Web Services? trend gains significant adoption, the need for a corresponding design approach becomes increasingly important. This paper introduces a foundational model for designing (composite) services. The innovation of this model lies in the identification of four interrelated viewpoints (interface behaviour, provider behaviour, choreography, and orchestration) and their formalization from a control-flow perspective in terms of Petri nets. By formally capturing the interrelationships between these viewpoints, the proposal enables the static verification of the consistency of composite services designed in a cooperative and incremental manner. A proof-of-concept simulation and verification tool has been developed to test the possibilities of the proposed model.

Service-oriented Design : A Multi-viewpoint Approach

Background FAIR (findability, accessibility, interoperability, and reusability) guiding principles seek the reuse of data and other digital research input, output, and objects (algorithms, tools, and workflows that led to that data) making them findable, accessible, interoperable, and reusable. GO FAIR - a bottom-up, stakeholder driven and self-governed initiative - defined a seven-step FAIRification process focusing on data, but also indicating the required work for metadata. This FAIRification process aims at addressing the translation of raw datasets into FAIR datasets in a general way, without considering specific requirements and challenges that may arise when dealing with some particular types of data. Objectives This scientific contribution addresses the architecture design of an open technological solution built upon the FAIRification process proposed by “GO FAIR” which addresses the identified gaps that such process has when dealing with health datasets. Methods A common FAIRification workflow was developed by applying restrictions on existing steps and introducing new steps for specific requirements of health data. These requirements have been elicited after analyzing the FAIRification workflow from different perspectives: technical barriers, ethical implications, and legal framework. This analysis identified gaps when applying the FAIRification process proposed by GO FAIR to health research data management in terms of data curation, validation, deidentification, versioning, and indexing. Results A technological architecture based on the use of Health Level Seven International (HL7) FHIR (fast health care interoperability resources) resources is proposed to support the revised FAIRification workflow. Discussion Research funding agencies all over the world increasingly demand the application of the FAIR guiding principles to health research output. Existing tools do not fully address the identified needs for health data management. Therefore, researchers may benefit in the coming years from a common framework that supports the proposed FAIRification workflow applied to health datasets. Conclusion Routine health care datasets or data resulting from health research can be FAIRified, shared and reused within the health research community following the proposed FAIRification workflow and implementing technical architecture.

/pdf/from-raw-data-to-fair-data-the-fairification-workflow-for-1z5m8r7wfc.pdf

From Raw Data to FAIR Data: The FAIRification Workflow for Health Research

Past research work on modeling and managing temporal information has, so far, failed to elicit support in commercial database systems. The increasing popularity of XML offers a unique opportunity to change this situation, inasmuch as XML and XQuery support temporal information much better than relational tables and SQL. This is the important conclusion claimed in this paper where we show that valid-time, transaction-time, and bitemporal databases can be naturally viewed in XML using temporally-grouped data models. Then, we show that complex historical queries, that would be very difficult to express in SQL on relational tables, can now be easily expressed in standard XQuery on such XML-based representations. We first discuss the management of transaction-time and valid-time histories and then extend our approach to bitemporal histories. The approach can be generalized naturally to support the temporal management of arbitrary XML documents and queries on their version history.

XBiT: An XML-based bitemporal data model

Time is a pervasive dimension of reality as everything evolves as time elapses. Therefore, Web-based information systems and knowledge representation tools at least mirror, and often have to capture, the time-varying and evolutionary nature of the phenomena they model and of the activities they support. This aspect has been acknowledged and long studied in the field of temporal databases [Jensen and Snodgrass 2009] but it truly applies also to the World Wide Web and Semantic Web in particular. Several papers addressing, in an explicit or implicit way, the representation and management of time and evolution in the Semantic Web appeared recently and, on some aspects, showed a clear upward trend in last years, witnessing a sustained and/or growing research interest. Reflecting and acknowledging such interest, we started in 2011 to collect references concerning the handling of time and evolution issues in Semantic Web research. As it was for [Grandi 2003], the purpose of this collection was to compile a bibliography which could be of help, in particular, to students and young researchers. As a result of such almost endless work, we wrote an annotated bibliography [Grandi 2012], whose latest version is available on the Web at URL:

/pdf/introducing-an-annotated-bibliography-on-temporal-and-j1r0ujrhlh.pdf

Introducing an annotated bibliography on temporal and evolution aspects in the semantic web

tXSchema (Currim et al., 2004) is a framework (a language and a suite of tools) for the creation and validation of time-varying XML documents. A tXSchema schema is composed of a conventional XML Schema annotated with physical and logical annotations. All components of a tXSchema schema can evolve over time to reflect changes in the real-world. Since many applications need to keep track of both data and schema evolution, schema versioning has been long advocated to be the best solution to do this. In this paper, we complete the tXSchema framework, which is predisposed from the origin to support schema versioning, with the definition of the operations which are necessary to exploit such feature and make schema versioning functionalities available to final users. Moreover, we propose a new technique for schema versioning in tXSchema, allowing a complete and safe management of schema changes. It supports both versioning of conventional schema and versioning of annotations, in an integrated manner. For each component of a tXSchema schema, our approach provides a complete and sound set of change primitives and a set of high-level change operations, for the maintenance of such a component and defines their operational semantics.

Schema Change Operations for Full Support of Schema Versioning in the τXSchema Framework

The W3C OWL 2 recommendation is an ontology language for the Semantic Web. It allows defining both schema (i.e., entities, axioms, and expressions) and instances (i.e., individuals) of ontologies. However, OWL 2 lacks explicit support for time-varying schema or for time-varying instances. Hence, knowledge engineers or maintainers of semantics-based Web resources have to use ad hoc techniques to specify OWL 2 time-varying ontologies. In this paper, for a disciplined and systematic approach to the temporal management of Semantic Web ontologies, we propose the adoption of a framework called temporal OWL 2 (
 $$\uptau $$
 OWL), which is inspired by the $$\uptau $$
 XSchema framework defined for XML data. In a way similar to what happens in $$\uptau $$
 XSchema, $$\uptau $$
 OWL allows creating a temporal OWL 2 ontology from a conventional (i.e., non-temporal) OWL 2 ontology and a set of logical and physical annotations. Logical annotations identify which elements of the ontology can vary over time; physical annotations specify how the time-varying aspects are represented in the OWL 2 document. Using annotations to integrate temporal aspects in the traditional Semantic Web, our framework (1) guarantees logical and physical data independence for temporal schemas and (2) provides a low-impact solution, since it requires neither modifications of existing Semantic Web ontologies, nor extensions to the OWL 2 recommendation and Semantic Web standards. Moreover, since the conventional schema and annotation documents could evolve over time to respond to new applications’ requirements, $$\uptau $$
 OWL supports temporal schema versioning by allowing changing these components and by keeping track of their evolution through the conventional schema versions and annotation document versions, respectively. Two complete sets of operations are proposed for changing the conventional schema and annotation documents; to complete the figure, a set of operations is also introduced for updating temporal schema which must be changed consequently each time one of the mentioned components evolves over time. To show the feasibility of our approach, a prototype tool, named $$\uptau $$
 OWL-Manager, is presented.

$$\uptau $$ τ OWL: A Systematic Approach to Temporal Versioning of Semantic Web Ontologies

τXSchema [7] is a framework (a language and a suite of tools) for the creation and validation of time-varying XML documents. A τXSchema schema is composed of a conventional XML Schema document annotated with physical and logical annotations. All components of a τXSchema schema (i.e., conventional schema, logical annotations, and physical annotations) can change over time to reflect changes in user requirements or in reference world of the database. Since many applications need to keep track of both data and schema evolution, schema versioning has been long advocated to be the best solution to do this. In this paper, we deal with schema versioning in the τXSchema framework. More precisely, we propose a set of schema change primitives for the maintenance of logical and physical annotations and define their operational semantics.

/pdf/schema-versioning-in-txschema-based-multitemporal-xml-14tm5t1nf1.pdf

Schema versioning in τXSchema-based multitemporal XML repositories

Although NoSQL databases are claimed to be schemaless, several NoSQL database vendors have chosen JSON as agile data representation format and provide a JSON-based API or query facility to simplify the life of application developers. Whereas many applications require the management of temporal data, the JSON Schema language lacks explicit support for time-varying data. In this paper, for a systematic approach to the management of temporal data in NoSQL databases, we propose a framework called Temporal JSON Schema (τJSchema), inspired by the τXSchema framework defined for XML data. τJSchema allows defining a temporal JSON schema from a conventional JSON schema and a set of temporal logical and physical characteristics. Our framework guarantees logical and physical data independence for temporal schemas and provides a low-impact solution since it requires neither modifications of existing JSON documents, nor extensions to the JSON format, the JSON Schema language, and all related tools and languages.

Zouhaier Brahmia

Papers

Schema Change Operations for Full Support of Schema Versioning in the τXSchema Framework

$$\uptau $$ τ OWL: A Systematic Approach to Temporal Versioning of Semantic Web Ontologies

Schema versioning in τXSchema-based multitemporal XML repositories

τJSchema: A Framework for Managing Temporal JSON-Based NoSQL Databases

XML data manipulation in conventional and temporal XML databases: A survey