Minimum Error Rate Training (MERT) and Minimum Bayes-Risk (MBR) decoding are used in most current state-of-theart Statistical Machine Translation (SMT) systems. The algorithms were originally developed to work with N-best lists of translations, and recently extended to lattices that encode many more hypotheses than typical N-best lists. We here extend lattice-based MERT and MBR algorithms to work with hypergraphs that encode a vast number of translations produced by MT systems based on Synchronous Context Free Grammars. These algorithms are more efficient than the lattice-based versions presented earlier. We show how MERT can be employed to optimize parameters for MBR decoding. Our experiments show speedups from MERT and MBR as well as performance improvements from MBR decoding on several language pairs. 1

Many contemporary language technology systems have been characterized by long pipelines of tools with complex dependencies. Too often, these workflows are implemented by ad hoc scripts; or, worse, tools are run manually, making experiments difficult to reproduce. These practices are difficult to maintain in the face of rapidly evolving workflows while they also fail to expose and record important details about intermediate data. Further complicating these systems are hyperparameters, which often cannot be directly optimized by conventional methods requiring users to determine which combination of values is best via trial and error. We describe LoonyBin, an open-source tool that addresses these issues by providing: 1) a visual interface for the user to create and modify workflows; 2) a well-defined mechanism for tracking metadata and provenance; 3) a script generator that compiles visual workflows into shell scripts, and 4) a new workflow representation we call a HyperWorkflow, which intuitively and succinctly encodes small experimental variations within a larger workflow. 1.