The joint scoring model is defined as follows: where the weight vector is defined by the vector concatenation w = w smt w ir , and q e refers to the yield that is determined uniquely by derivation h. Following the interpretation of our joint model as forced or constrained decoding, we can view pipeline approaches such as the direct translation baseline as instances of unconstrained decoding.
the SMT decoder yields a single translation output for every document and the assignment of document scores is deferred to a (monolingual) retrieval model given this single output structure.