Visual data exploration is ubiquitous in nearly every industry and organization to support
discovering data-driven actionable insights. However, unlocking those insights requires …

To support effective data exploration, there has been a growing interest in developing
solutions that can automatically recommend data visualizations that reveal interesting and …

The complexity of building biological databases is well-known and ontologies play an
extremely important role in biological databases. However, much of the emphasis on the …

In big data query processing, there is a trade-off between query accuracy and query
efficiency, for example, sampling query approaches trade-off query completeness for …

Query rewriting in heterogeneous environments assumes mappings that are complete. In
reality and especially in the Big Data era it is rarely the case that such complete sets of …

Interactive data exploration platforms in Web, business and scientific domains are becoming
increasingly popular. Typically, users without prior knowledge of data interact with these …

Data analysis in rich spaces of heterogeneous data sources is an increasingly common
activity. Examples include exploratory data analysis and personal information management …

Nowadays, query optimization has been highly concerned in big data management,
especially in NoSQL databases. Approximate queries boost query performance by loss of …

Database users are easily overwhelmed by the sheer size of data found in large-scale
scientific and financial databases. Exploring these databases to make sense of the explored …

Περίληψη Η παρούσα διπλωματική εργασία ανήκει στον τομέα της Ολοκλήρωσης Δεδομένων
(Data Integration). Συγκεκριμένα μελετά την ομοιότητα ερωτημάτων για την προσεγγιστική …