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Documents authored by Santos, André Fernandes dos



Santos, André Fernandes dos

Document
Derzis: A Path Aware Linked Data Crawler

Authors: André Fernandes dos Santos and José Paulo Leal

Published in: OASIcs, Volume 94, 10th Symposium on Languages, Applications and Technologies (SLATE 2021)


Abstract
Consuming Semantic Web data presents several challenges, from the number of datasets it is composed of, to the (very) large size of some of those datasets and the uncertain availability of querying endpoints. According to its core principles, accessing linked data can be done simply by dereferencing the IRIs of RDF resources. This is a light alternative both for clients and servers when compared to dataset dumps or SPARQL endpoints. The linked data interface does not support complex querying, but using it recursively may suffice to gather information about RDF resources, or to extract the relevant sub-graph which can then be processed and queried using other methods. We present Derzis, an open source semantic web crawler capable of traversing the linked data cloud starting from a set of seed resources. Derzis maintains information about the paths followed while crawling, which allows to define property path-based restrictions to the crawling frontier.

Cite as

André Fernandes dos Santos and José Paulo Leal. Derzis: A Path Aware Linked Data Crawler. In 10th Symposium on Languages, Applications and Technologies (SLATE 2021). Open Access Series in Informatics (OASIcs), Volume 94, pp. 2:1-2:12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


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@InProceedings{santos_et_al:OASIcs.SLATE.2021.2,
  author =	{Santos, Andr\'{e} Fernandes dos and Leal, Jos\'{e} Paulo},
  title =	{{Derzis: A Path Aware Linked Data Crawler}},
  booktitle =	{10th Symposium on Languages, Applications and Technologies (SLATE 2021)},
  pages =	{2:1--2:12},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-202-0},
  ISSN =	{2190-6807},
  year =	{2021},
  volume =	{94},
  editor =	{Queir\'{o}s, Ricardo and Pinto, M\'{a}rio and Sim\~{o}es, Alberto and Portela, Filipe and Pereira, Maria Jo\~{a}o},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2021.2},
  URN =		{urn:nbn:de:0030-drops-144198},
  doi =		{10.4230/OASIcs.SLATE.2021.2},
  annote =	{Keywords: Semantic web, linked open data, RDF, crawler}
}

Santos, André C.

Document
Specifying Adaptations through a DSL with an Application to Mobile Robot Navigation

Authors: André C. Santos, João M. P. Cardoso, Pedro C. Diniz, and Diogo R. Ferreira

Published in: OASIcs, Volume 29, 2nd Symposium on Languages, Applications and Technologies (2013)


Abstract
Developing applications for resource-constrained embedded systems is a challenging task specially when applications must adapt to changes in their operating conditions or environment. To ensure an appropriate response at all times, it is highly desirable to develop applications that can dynamically adapt their behavior at run-time. In this paper we introduce an architecture that allows the specification of adaptable behavior through an external, high-level and platform-independent domain-specific language (DSL). The DSL is used here to define adaptation rules that change the run-time behavior of the application depending on various operational factors, such as time constraints. We illustrate the use of the DSL in an application to mobile robot navigation using smartphones, where experimental results highlight the benefits of specifying the adaptable behavior in a flexible and external way to the main application logic.

Cite as

André C. Santos, João M. P. Cardoso, Pedro C. Diniz, and Diogo R. Ferreira. Specifying Adaptations through a DSL with an Application to Mobile Robot Navigation. In 2nd Symposium on Languages, Applications and Technologies. Open Access Series in Informatics (OASIcs), Volume 29, pp. 219-234, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


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@InProceedings{santos_et_al:OASIcs.SLATE.2013.219,
  author =	{Santos, Andr\'{e} C. and Cardoso, Jo\~{a}o M. P. and Diniz, Pedro C. and Ferreira, Diogo R.},
  title =	{{Specifying Adaptations through a DSL with an Application to Mobile Robot Navigation}},
  booktitle =	{2nd Symposium on Languages, Applications and Technologies},
  pages =	{219--234},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-52-1},
  ISSN =	{2190-6807},
  year =	{2013},
  volume =	{29},
  editor =	{Leal, Jos\'{e} Paulo and Rocha, Ricardo and Sim\~{o}es, Alberto},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2013.219},
  URN =		{urn:nbn:de:0030-drops-40403},
  doi =		{10.4230/OASIcs.SLATE.2013.219},
  annote =	{Keywords: Domain-specific language, run-time adaptations, adaptive behavior, embedded systems, mobile robot navigation}
}

Santos, André

Document
Short Paper
Narrative Extraction from Semantic Graphs (Short Paper)

Authors: Daniil Lystopadskyi, André Santos, and José Paulo Leal

Published in: OASIcs, Volume 113, 12th Symposium on Languages, Applications and Technologies (SLATE 2023)


Abstract
This paper proposes an interactive approach for narrative extraction from semantic graphs. The proposed approach extracts events from RDF triples, maps them to their corresponding attributes, and assembles them into a chronological sequence to form narrative graphs. The approach is evaluated on the Wikidata graph and achieves promising results in terms of narrative quality and coherence. The paper also discusses several avenues for future work, including the integration of machine learning, graph embedding methods and the exploration of advanced techniques for attention-based narrative labeling and semantic role labeling. Overall, the proposed method offers a promising approach to narrative extraction from semantic graphs and has the potential to be useful in various applications, including chatbots, conversational agents, and content creation tools.

Cite as

Daniil Lystopadskyi, André Santos, and José Paulo Leal. Narrative Extraction from Semantic Graphs (Short Paper). In 12th Symposium on Languages, Applications and Technologies (SLATE 2023). Open Access Series in Informatics (OASIcs), Volume 113, pp. 9:1-9:8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{lystopadskyi_et_al:OASIcs.SLATE.2023.9,
  author =	{Lystopadskyi, Daniil and Santos, Andr\'{e} and Leal, Jos\'{e} Paulo},
  title =	{{Narrative Extraction from Semantic Graphs}},
  booktitle =	{12th Symposium on Languages, Applications and Technologies (SLATE 2023)},
  pages =	{9:1--9:8},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-291-4},
  ISSN =	{2190-6807},
  year =	{2023},
  volume =	{113},
  editor =	{Sim\~{o}es, Alberto and Ber\'{o}n, Mario Marcelo and Portela, Filipe},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2023.9},
  URN =		{urn:nbn:de:0030-drops-185231},
  doi =		{10.4230/OASIcs.SLATE.2023.9},
  annote =	{Keywords: Narratives, Narrative Extraction, Information Retrieval, Knowledge Graphs, Semantic Graphs, Resource Description Framework, Web Ontology}
}
Document
Large Semantic Graph Summarization Using Namespaces

Authors: Ana Rita Santos Lopes da Costa, André Santos, and José Paulo Leal

Published in: OASIcs, Volume 104, 11th Symposium on Languages, Applications and Technologies (SLATE 2022)


Abstract
We propose an approach to summarize large semantics graphs using namespaces. Semantic graphs based on the Resource Description Framework (RDF) use namespaces on their serializations. Although these namespaces are not part of RDF semantics, they have intrinsic meaning. Based on this insight, we use namespaces to create summary graphs of reduced size, more amenable to be visualized. In the summarization, object literals are also reduced to their data type and the blank nodes to a group of their own. The visualization created for the summary graph aims to give insight of the original large graph. This paper describes the proposed approach and reports on the results obtained with representative large semantic graphs.

Cite as

Ana Rita Santos Lopes da Costa, André Santos, and José Paulo Leal. Large Semantic Graph Summarization Using Namespaces. In 11th Symposium on Languages, Applications and Technologies (SLATE 2022). Open Access Series in Informatics (OASIcs), Volume 104, pp. 12:1-12:9, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{dacosta_et_al:OASIcs.SLATE.2022.12,
  author =	{da Costa, Ana Rita Santos Lopes and Santos, Andr\'{e} and Leal, Jos\'{e} Paulo},
  title =	{{Large Semantic Graph Summarization Using Namespaces}},
  booktitle =	{11th Symposium on Languages, Applications and Technologies (SLATE 2022)},
  pages =	{12:1--12:9},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-245-7},
  ISSN =	{2190-6807},
  year =	{2022},
  volume =	{104},
  editor =	{Cordeiro, Jo\~{a}o and Pereira, Maria Jo\~{a}o and Rodrigues, Nuno F. and Pais, Sebasti\~{a}o},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2022.12},
  URN =		{urn:nbn:de:0030-drops-167585},
  doi =		{10.4230/OASIcs.SLATE.2022.12},
  annote =	{Keywords: Semantic graph, RDF, namespaces, reification}
}
Document
DAOLOT: A Semantic Browser

Authors: João Bruno Silva, André Santos, and José Paulo Leal

Published in: OASIcs, Volume 83, 9th Symposium on Languages, Applications and Technologies (SLATE 2020)


Abstract
The goal of the Semantic Web is to allow the software agents around us and AIs to extract information from the Internet as easily as humans do. This semantic web is a network of connected graphs, where relations between concepts and entities make up a layout that is very easy for machines to navigate. At the moment, there are only a few tools that enable humans to navigate this new layer of the Internet, and those that exist are for the most part very specialized tools that require from the user a lot of pre-existing knowledge about the technologies behind this structure. In this article we report on the development of DAOLOT, a search engine that allows users with no previous knowledge of the semantic web to take full advantage of its information network. This paper presents its design, the algorithm behind it and the results of the validation testing conducted with users. The results of our validation testing show that DAOLOT is useful and intuitive to users, even those without any previous knowledge of the field, and provides curated information from multiple sources instantly about any topic.

Cite as

João Bruno Silva, André Santos, and José Paulo Leal. DAOLOT: A Semantic Browser. In 9th Symposium on Languages, Applications and Technologies (SLATE 2020). Open Access Series in Informatics (OASIcs), Volume 83, pp. 5:1-5:11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{silva_et_al:OASIcs.SLATE.2020.5,
  author =	{Silva, Jo\~{a}o Bruno and Santos, Andr\'{e} and Leal, Jos\'{e} Paulo},
  title =	{{DAOLOT: A Semantic Browser}},
  booktitle =	{9th Symposium on Languages, Applications and Technologies (SLATE 2020)},
  pages =	{5:1--5:11},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-165-8},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{83},
  editor =	{Sim\~{o}es, Alberto and Henriques, Pedro Rangel and Queir\'{o}s, Ricardo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2020.5},
  URN =		{urn:nbn:de:0030-drops-130188},
  doi =		{10.4230/OASIcs.SLATE.2020.5},
  annote =	{Keywords: Semantic, Web, Named Entities, Search, SPARQL, RDF, COMUNICA}
}
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