data that must be targeted to under

data that must be targeted to understand, plan and act in a predictive way. This perspective raises new questions about the quality of the data. In this context, people do not agree with the definition of quality. The quality of the data may be its high processing level or its relevance according to the reality they represent. In fact, since Big Data is big and messy, challenges can be classified into engineering tasks (managing data at an unimaginable scale) and semantics (finding and meaningfully combining information that is relevant to your needs) [36] have identified each a relevant challenge for Big Data: