16. A system for predicting the translation quality of a translated input document comprising: memory which stores: a machine translation component for translating sentences of an input document from a source language to a target language to provide a translated input document comprising a plurality of sentence pairs, the translation of the sentences being performed using biphrases drawn from a phrase table or partial parse trees; a feature extraction component which generates a representation of each of the sentence pairs, based on a set of features extracted for the sentence pair; a document-level representation component which uses a generative model to generate a fixed-length representation of the input document, based on the sentence pair representations; a prediction component for predicting a translation quality of the translated input document based on the representation of the input document; and a decision component for outputting a decision based on the predicted translation quality of the translated input document; and a processor which implements the machine translation component, feature extraction component, document level representation component, and prediction component, and decision component.
16. A system for predicting the translation quality of a translated input document comprising: memory which stores: a machine translation component for translating sentences of an input document from a source language to a target language to provide a translated input document comprising a plurality of sentence pairs, the translation of the sentences being performed using biphrases drawn from a phrase table or partial parse trees; a feature extraction component which generates a representation of each of the sentence pairs, based on a set of features extracted for the sentence pair; a document-level representation component which uses a generative model to generate a fixed-length representation of the input document, based on the sentence pair representations; a prediction component for predicting a translation quality of the translated input document based on the representation of the input document; and a decision component for outputting a decision based on the predicted translation quality of the translated input document; and a processor which implements the machine translation component, feature extraction component, document level representation component, and prediction component, and decision component. 18. The system of claim 16 , further comprising a training component for learning parameters of the generative model.