13. The method of claim 12 , wherein the unified representation of the query further includes a blurred feature-based representation generated by modifying the feature-based vector based on the reconstructed feature-based vector.
12. A method, implemented on a machine having at least one processor, storage, and a communication platform connected to a network for search and retrieval of information archived based on a unified representation, comprising the steps of: obtaining a query via the communication platform; processing, by a query processor, the query to generate a feature-based vector characterizing the query; generating, by a semantic extractor, a semantic-based representation of the query based on the feature-based vector, wherein the semantic-based representation has a reduced dimension; constructing, by a reconstruction unit, a reconstructed feature-based vector based on the semantic-based representation of the query, by mapping the semantic-based representation to a feature space of the feature-based vector; comparing, by a discrepancy analyzer, the feature-based vector with the reconstructed feature-based vector to identify a difference between the feature-based vector and the reconstructed feature-based vector; forming a residual feature-based representation of the query based on the difference between the feature-based vector and the reconstructed feature-based vector; generating, by a unified representation construction unit, a unified representation of the query based on the semantic-based representation and the residual feature-based representation; retrieving, by a candidate search unit, information relevant to the query from an information archive based on the unified representation of the query; generating, by a query response generator, a query response based on the information relevant to the query retrieved from the information archive; and transmitting the query response to respond to the query.