- FIBO/RIF work done by Dean about a year ago. It is a proper subset of RIF, and hence conforms to a W3C standard, and can be converted into SPIN and MarkLogic rules. There is no easy way to edit/view rules in RIF. It's connection to OWL is defined in the RIF standard.
- SPIN from TopQuadrant etc. Based on SPARQL, a W3C Recommendation, but the SPIN extension is just a working note. Runs on any SPARQL-enabled triple store (that's all of the ones that are actually compliant), can be edited/viewed using TopBraid Composer. Connection to RDF/OWL is part of the spec. No translations available, but there is a command-line version that can be used for unit tests.
- SWRL available in Protege for ages. It is not a W3C standard, can be edited and viewed in Protege. Connection to OWL is part of the spec. Unit tests can be performed in Protege
- Decision Model and Notation (DMN) an OMG standard http://omg.org/spec/DMN/ that uses Decision Tables and an expression language (FEEL). It's being directly supported by the major rules engine vendors such as IBM (ILog/JRules), Oracle and TIBCO.
- Other candidates might include Flora-2, which is what the Sunflower implementation by SRI/Quarule uses, and is also used by Benjamin Grosof's implementation. It has higher expressivity than RIF/BLD (see http://www.w3.org/TR/2013/REC-rif-bld-20130205/), and is open source, though not a standard per se. A starting point write-up on the mapping from RIF to Rulelog is available at http://ruleml.org/rif/rulelog/rif/RIF-Rulelog.html. The Sunflower implementation supports validation, has a rule editor, imports OWL as the basis for rule development, etc., and I believe the same is true / planned for the Coherent-based implementation. Both use Flora-2, by Michael Kifer, described at http://flora.sourceforge.net/. Flora-2 is "in the same spirit" as RIF, since Michael worked on both and continues to support it, but there may not be a direct mapping document available at present. SRI might be willing to make Sunflower available for unit test support (stay tuned).
- There are other implementations of RuleML, such as prova, which is Adrian Paschke's implementation, which provides Reactive RuleML support – see https://prova.ws/. This work includes a prova syntax, with mappings from various flavors of RuleML, including ECA RuleML (event-condition-action). http://wiki.ruleml.org/index.php/RuleML_Home
- Yet another candidate might include the Hets system, which is related to the DOL/OntoIOp effort. The focus there is on CL and declarative monotonic logics, so this may or may not work for us. See http://www.informatik.uni-bremen.de/agbkb/forschung/formal_methods/CoFI/hets/index_e.htm for more on this.