15. A domain classification system for domain based natural language processing, comprising: memory storing: query models each for a domain of a set of domains and comprising at least an ontology having a set of semantic tokens organized in hierarchical levels, and a set of domain-specific semantic constructions each including one or more of the semantic tokens linked by one of a set of predefined grammatical relations; trigram corpora, each corpus for a domain of the set of domains and each having entries comprising: trigrams obtained based on the query model of the domain, each trigram having a first, second and third semantic token; and corresponding trigram probabilities each representing a relative probability that the third semantic token appearing in the trigrams given the first and the second sematic tokens; and computer executable instructions; and a processor in communication with the memory, and when executing the instructions, configured to implement software components comprising: a receiving component configured to receive an input text from a remote device via a network connection; a set of domain relevance analyzer components corresponding to the set of domains configured to determine relevance scores for the input text with respect to the set of domains based on tokenized sequences of the input text corresponding to the set of domains, the query models, and the trigram corpora; a classifier component configured to classify the input text among the set of domains based on the relevance scores with respect to the set of domains for the input text; and a component configured to transmit, to the remote device, a communication comprising the input text based upon the classifying.
16. The domain classification system of claim 15 , wherein the processor, when executing the instructions, is further configured to implement software components comprising: a semantic construction expander component configured to obtain one expanded set of semantic constructions as semantic corpus for each domain by replacing at least one of the semantic tokens of at least one of the semantic constructions of the query model of the domain with corresponding semantic tokens at a lower hierarchical level in the ontology of the query model of the domain; and a trigram generator component configured to generate the trigram corpora by: generating the trigrams for each domain based on the expanded set of semantic constructions for the domain; and obtaining the trigram probabilities corresponding to the trigrams for each domain.