Ontologies are constructed to extract meaningful information from data sources. Constructing ontologies aim at capturing domain knowledge that gives a commonly agreed understanding of a domain, which may be reused, shared, among applications and groups. To ease the process of building ontologies...

Micro blogging sites have become important forums for discussion during disaster events in which Twitter has become one of the important source of real time information. Millions of tweets are posted during disasters, which include not only information about the present situation or relief...

Purpose With the development of systems and applications, the number of users interacting with databases has increased considerably. The relational database model is still considered as the most used model for data storage and manipulation. However, it does not offer any semantic support for the...