Pesquisa de Doutorado da Veronica

 Abstract ... While ILP is a mature field, mining logical rules from KBs is difficult, because KBs make an open-world assumption. This means that absent information cannot be taken as counterexamples. ... 1 Introduction In recent years, however, the KBs have become so large that they can themselves be mined for information. It is possible to find rules in the KBs that describe common correlations in the data. [As regras se baseiam nas instâncias para extrair estes padrões SE-ENTÃO] Since RDF has only positive inference rules, these KBs contain only positive statements and no negations. Furthermore, they operate under the open-world assumption (OWA). Under the OWA, a statement that is not contained in the KB is not necessarily false; it is just unknown. This is a crucial difference to many standard database settings that operate under the closed-world assumption(CWA). Consider an example KB that does not contain the information that a particular person is married. Under the CWA, we ...

Čebirić, Š., Goasdoué, F., Kondylakis, H. et al. Summarizing semantic graphs: a survey. The VLDB Journal 28, 295–327 (2019). https://doi.org/10.1007/s00778-018-0528-3 Abstract The explosion in the amount of the available RDF data has lead to the need to explore, query and understand such data sources. Due to the complex structure of RDF graphs and their heterogeneity, the exploration and understanding tasks are significantly harder than in relational databases, where the schema can serve as a first step toward understanding the structure. [ Conhecer o esquema ajuda na exploração ] Summarization has been applied to RDF data to facilitate these tasks. Its purpose is to extract concise and meaningful information from RDF knowledge bases, representing their content as faithfully as possible. There is no single concept of RDF summary, and not a single but many approaches to build such summaries; each is better suited for some uses, and each presents specific challenges with respect to its ...

Por Gerhard Weikum ABSTRACT ... Over the last 15 years, huge knowledge bases, also known as knowledge graphs, have been automatically constructed from web data, and have become a key asset for search engines and other use cases. [KG é KB, segundo o autor] Machine knowledge can be harnessed to semantically interpret texts in news, social media and web tables, contributing to question answering, natural language processing and data analytics. It highlights the role of "DB thinking" in building and maintaining high-quality knowledge bases from web contents. [Selecionar as fontes com cuidado, modelar os dados] 1 INTRODUCTION ... automatic construction of large-scale high-quality knowledge bases (KBs), distilling noisy Internet content into crisp statements on entities, their attributes and relationships between them. Today, publicly available KBs, such as BabelNet ..., DBpedia ... , Wikidata ...  or Yago, feature hundred millions of entities ... and many billions of statements ab...

 Affolter, K., Stockinger, K. & Bernstein, A. A comparative survey of recent natural language interfaces for databases. The VLDB Journal 28, 793–819 (2019). https://doi.org/10.1007/s00778-019-00567-8 Abstract We categorize the NLIs into four groups based on the methodology theyare using: keyword-, pattern-, parsing-, and grammar based NLI. Overall, we learned that keyword-based systems are enough to answer simple questions. To solve more complex questions involving subqueries, the system needs to apply some sort of parsing to identify structural dependencies. Grammar-based systems are overall the most powerful ones, but are highly dependent on their manually designed rules. [BGP para keyword, CGP para parsing. Pattern podem ajudar a incluir contexto: Qual é (Quais são) X Qual foi (Quais foram)] 1 Introduction Even though SQL was initially developed to be used by business people, reality shows that even technically-skilled users often experience problems putting together correct...