Requirement for computerised knowledge representation (KR) formats

There are lots of ways of expressing knowledge in digital formats. Choosing the right KR format may not seem a big issue until you start considering the longer term maintenance issues. With that in mind, this is my requirements list for the ideal KR format:

• Translatable to and from formats that are easily (a) readable by humans and (b) processable by computers (after all that is the whole point, isn't it?)
• "Normalised" so that each fact only needs to occur once in the knowledge base
• Shareable between organisations
• Decomposable into small components
• Amenable to configuration management
• Amenable to quality assurance and validation

Meeting the above criteria is why I've fallen into thinking the optimal knowledge base will have combination of four primary formats:

1. semantic networks (think of page of labelled circles with labelled arrows linking them)
2. fact tables
3. where necessary "programming language" style computer script for expressing complex conditional statements and mathematical formulas
4. a test case library for pairs of "inputs" (eg formalised patient descriptions) and "outputs" (eg CDS conclusions)