As we noted earlier, one of the goals of the project is to provide developers and maintainers of KOS with the means to author and update those KOS within the Registry environment. While we are committed to being as open as possible in terms of encodings for existing KOS imported into the Registry, by necessity we must be more selective in the scheme authoring environment we implement. Initially we will be developing an editor and validator conforming to the Simple Knowledge Organization System (SKOS) (http://www.w3.org/TR/2005/WD-swbp-skos-core-spec-20051102/). Where possible, we will build on existing work in this area— see, for example the W3C work on SKOS validation (http://www.w3.org/2004/02/ skos/core/validation).
Framing the Registry’s built-in authoring environment on the evolving SKOS is not without its problems. Currently, there is no direct support in SKOS for handling versioning of KOS concepts. From the beginning of the project, we recognized the absolute need to manage versioning of schemes and schemas as well as their member concepts and terms. It is to these issues that we now turn. We will return to the current limitations of SKOS near the end of the paper.