The Bubble Navigator is a tool for visual navigation of semi-structured or semantic web data. Its main strength is the ability to visualize a vast amount of data and to provide full-text search in real-time. When the tool is opened, all data are instantly aggregated (counted) and the user is presented with bubbles representing the count of each document type (article, person, place, location, …). The user can then input a full-text query which is instantly executed and the aggregations are updated. At any given time, the user can press the Add filter button and all the properties of all found resources are aggregated. The size of bubbles again shows the count of a given property. E.g. for the person document type, the largest bubble is the birth year (it means that most of the person documents contain this field), for the birth year the largest bubble is the range 1966-1992. This means that most of the people in the DBpedia database were born in 1966-1992.
All this is possible due to the ElasticSearch tool running in the background. We have indexed the complete DBpedia database from August 2015. The aggregations are configured to deal with string fields, numbers, and date ranges. ElasticSearch provides instant aggregations (counts, statistics) of the data. Full-text queries are available all the time. It is even possible to input phrase searches, multi-field searches, fuzzy operators, and filed boosting. The text data are analyzed (stemmed, tokenized) and the analyzers are available for many languages. In our demo, we show that the Semantic Web content can be effectively browsed using advanced indexing tools.
Ondřej Pražák, University of West Bohemia in Pilsen