Valeria Magalhaes Pequeno
@enautica.pt
Departamento de Engenharia Marítima
Escola Superior Náutica Infante D. Henrique
RESEARCH, TEACHING, or OTHER INTERESTS
Computer Science, Information Systems, Computer Science Applications, Computer Engineering
Scopus Publications
Scopus Publications
Vania Vidal, Valéria Magalhães Pequeno, Narciso Moura Arruda Júnior, and Marco Antonio Casanova
Emerald
Purpose Enterprise knowledge graphs (EKG) in resource description framework (RDF) consolidate and semantically integrate heterogeneous data sources into a comprehensive dataspace. However, to make an external relational data source accessible through an EKG, an RDF view of the underlying relational database, called an RDB2RDF view, must be created. The RDB2RDF view should be materialized in situations where live access to the data source is not possible, or the data source imposes restrictions on the type of query forms and the number of results. In this case, a mechanism for maintaining the materialized view data up-to-date is also required. The purpose of this paper is to address the problem of the efficient maintenance of externally materialized RDB2RDF views. Design/methodology/approach This paper proposes a formal framework for the incremental maintenance of externally materialized RDB2RDF views, in which the server computes and publishes changesets, indicating the difference between the two states of the view. The EKG system can then download the changesets and synchronize the externally materialized view. The changesets are computed based solely on the update and the source database state and require no access to the content of the view. Findings The central result of this paper shows that changesets computed according to the formal framework correctly maintain the externally materialized RDB2RDF view. The experiments indicate that the proposed strategy supports live synchronization of large RDB2RDF views and that the time taken to compute the changesets with the proposed approach was almost three orders of magnitude smaller than partial rematerialization and three orders of magnitude smaller than full rematerialization. Originality/value The main idea that differentiates the proposed approach from previous work on incremental view maintenance is to explore the object-preserving property of typical RDB2RDF views so that the solution can deal with views with duplicates. The algorithms for the incremental maintenance of relational views with duplicates published in the literature require querying the materialized view data to precisely compute the changesets. By contrast, the approach proposed in this paper requires no access to view data. This is important when the view is maintained externally, because accessing a remote data source may be too slow.
Manuel Cortes P. Belchior Sousa, Adriana Lopes Fernandes, and Valeria Magalhaes Pequeno
IEEE
The Covid-19 pandemic had an unprecedented impact on the tourism industry. It is believed that the recovery of the sector goes through a strong investment in technologies that allow creating and managing tourists' perception of the virtual image of tourist destinations. This article proposes a discussion about the relevance of User Generated Content (UGC) to reveal the virtual image of a tourist destination, in order to contribute to the creation of a Smart Tourism Destination (STD). The virtual image is studied from the perspective of the public transport system due to the fact that its improvement is one of the objectives of the Tourism of Portugal strategic plan for the creation of a STD in the decade 2017 - 2027. The methodology used was qualitative, through a bibliographical research, in which the key factors of this theme were addressed. After the study carried out it was concluded that the exploration of UGCs can allow managers and regulatory and tourism promoting entities to extract a lot of interesting information about how to take better advantage of the technologies adopted to create value for tourists.
Narciso Arruda, J. Alcântara, V. Vidal, Angelo Brayner, M. Casanova, V. Pequeno, and Wellington Franco
SCITEPRESS - Science and Technology Publications
For several applications, an integrated view of linked data, denoted linked data mashup, is a critical requirement. Nonetheless, the quality of linked data mashups highly depends on the quality of the data sources. In this sense, it is essential to analyze data source quality and to make this information explicit to consumers of such data. This paper introduces a fuzzy ontology to represent the quality of linked data source. Furthermore, the paper shows the applicability of the fuzzy ontology in the process of evaluating data source quality used to build linked data mashups.
Caio Avila, Anderson Calixto, Tulio Rolim, Wellington Franco, Amanda Venceslau, Vânia Vidal, Valéria Pequeno, and Francildo Felix De Moura
SCITEPRESS - Science and Technology Publications
Brazil is one of the countries with the highest level of drug consumption in the world. By 2012 about 66% claimed to practice self-medication. Such activity can lead to a wide range of risks, including death from drug intoxication. Studies indicate that a lack of knowledge about drugs and their dangers is one of the main aggravating factors in this scenario. This work aims to universalize access to information about medications and their risks for different user profiles, especially Brazilian and lay users. In this paper, we presented the construction process of a Linked Data Mashup (LDM) integrating the datasets: consumer drug prices, government drug prices and drug’s risks in pregnant from ANVISA and SIDER from BIO2RDF. In addition, this work presents MediBot, an ontology-based chatbot capable of responding to requests in natural language in Portuguese through the instant messenger Telegram, smoothing the process to query the data. MediBot acts like a native language query interface on an LDM that works as an abstraction layer that provides an integrated view of multiple heterogeneous data sources.
Amanda Venceslau, Rossana Andrade, Vânia Vidal, Tales Nogueira, and Valéria Pequeno
SCITEPRESS - Science and Technology Publications
The Internet of Things (IoT) is a paradigm in which the Internet connects people and the environment using devices and services that are spread in the user daily routine. In this scenario, different agents, devices and services are able to exchange data and knowledge using a common vocabulary or mappings that represent and integrate heterogeneous sources. This semantic interoperability is facilitated by the Semantic Web that provides consolidated technologies, languages and standards, offering data and platforms interoperability. In this context, this work reviews and analyzes the state-of-the-art of IoT semantic interoperability, investigating and presenting not only which Semantic Web technologies are employed but also the challenges that support the studies in this area of research.
Valéria M. Pequeno, Vânia M. P. Vidal, and Tiago Vinuto
SCITEPRESS - Science and Technology Publications
Translating data from linked data sources to the vocabulary that is expected by a linked data application requires a large number of mappings and can require a lot of structural transformations as well as complex property value transformations. The R2R mapping language is a language based on SPARQL for publishing expressive mappings on the web. However, the specification of R2R mappings is not an easy task. This paper therefore proposes the use of mapping patterns to semi-automatically generate R2R mappings between RDF vocabularies. In this paper, we first specify a mapping language with a high level of abstraction to transform data from a source ontology to a target ontology vocabulary. Second, we introduce the proposed mapping patterns. Finally, we present a method to semi-automatically generate R2R mappings using the mapping
Vânia M. P. Vidal, Narciso Arruda, Matheus Cruz, Marco A. Casanova, Valéria M. Pequeno, and Ticianne Darin
Springer International Publishing
Vânia M. P. Vidal, Marco A. Casanova, Elisa S. Menendez, Narciso Arruda, Valeria M. Pequeno, and Luiz A. Paes Leme
Springer International Publishing
Vânia M. P. Vidal, Marco A. Casanova, Valéria M. Pequeno, Narciso Arruda, Diego Sá, and José M. Monteiro
Springer International Publishing
Valéria Pequeno, Helena Galhardas, and Vânia M. Ponte Vidal
Springer International Publishing
Valéria M. Pequeno, Vania M. P. Vidal, Marco A. Casanova, Luís Eufrasio T. Neto, and Helena Galhardas
ACM Press
The W3C RDB2RDF Working Group proposed a standard language to map relational data into RDF triples, called R2RML. However, creating R2RML mappings may sometimes be a difficult task because it involves the creation of views (within the mappings or not) and referring to them in the R2RML mapping. To overcome such difficulty, this paper first proposes algebraic correspondence assertions, which simplify the definition of relational-to-RDF mappings and yet are expressive enough to cover a wide range of mappings. Algebraic correspondence assertions include data-metadata mappings (where data elements in one schema serve as metadata components in the other), mappings containing custom value functions (e.g., data format transformation functions) and union, intersection and difference between tables. Then, the paper shows how to automatically compile algebraic correspondence assertions into R2RML mappings.
V. Pequeno and H. Galhardas
SCITEPRESS - Science and and Technology Publications
When dealing with the data integration problem, the designer usually encounters incompatible data models characterized by differences in structure and semantics, even in the context of a same organization. In this work, we propose a declarative and formal approach to specify correspondences between relational schema components. Our Correspondence Assertions (CAs) can specify 1-to-1 and m-to-n correspondences with semantics. We propose to adapt CAs to be able to express schema matching between relational schemas, as well as to extend this formalism with new types of CAs to deal with joins, outer-joins, and data-metadata relationships. Finally, we demonstrate how mapping expressions in the form of SQL queries can be generated from CAs.
Valéria Magalhães Pequeno and João Carlos Moura Pires
ACM Press
Sharing and integrating information across multiple autonomous and heterogeneous data sources has emerged as a strategic requirement in modern business. We deal with this problem by proposing a declarative approach based on the creation of a reference model and perspective schemata. The former serves as a common semantic meta-model, while the latter defines correspondence between schemata. Furthermore, using the proposed architecture, we developed an inference mechanism which allows the (semi-) automatic derivation of new mappings between schemata from previous ones. The aim of this paper is to present the proposed inference mechanism.
Valéria Magalhães Pequeno and João Carlos Moura Pires
Springer Berlin Heidelberg