What's the purpose and mechanism of Ontology in D3WEB

Question

In the expert system D3WEB, it is possible to insert\develop\use Ontology. However, I cannot get the point what's the purpose to introduce ontology in D3WEB?

The nice example on this page, https://www.d3web.de/Wiki.jsp?page=Demo%20-%20Ontology , shows how to develop an ontology in D3WEB. In my opinion, it can be more efficiently developed using Protégé. If the contents shall be changed with a real application, for instance, an ontology about 'dog', in the real application there could be instance dog A, B, C, D. It might be not feasible to 'insert' the instances into the D3WEB knowledge base. However, if the ontology changes over time, how to use the ontology in D3WEB then?

In my opinion, the best way is to develop an ontology outside of D3WEB using Java code. However, I believe the designer of D3WEB would have a nice reason to introduce ontology in D3WEB. I will appreciate it if someone let me know.

Answer 1

This is a somewhat common question we get regarding d3web-KnowWE, one reason might be, that our naming is somewhat misleading. So let me explain.

First there is d3web the java framework to run knowledge bases with strong problem solving knowledge, including rules, decision trees, flow-charts, covering lists, cost-benefit dialog strategies, time based reasoning, and so on. This framework in its core does not provide any GUIs, but is meant to integrate problem solving capabilities in other applications/expert systems. It also does not provide a way to properly create/author the knowledge bases it runs, aside maybe from doing it in the Java code on an API level.

To also provide proper means to author and develop a knowledge base, including some basic dialogs to run, demo, test, and debug the authored knowledge bases, we began working on the wiki system KnowWE, which today is basically a heavily extended JSPWiki. The page d3web.de itself for example is also just a build of KnowWE with specific content. While we were working on and with KnowWE, we began to really like the approach to edit and author large knowledge bases in this 'wiki way', were you automatically support multiple distributed users to work on the same knowledge base, have automatic versioning, can add nice documentation directly beside the actual formal knowledge, can generate knowledge using script (because it's all just simple text markup), and so forth. Also, the underlying architecture of KnowWE became quite good and mature over the years.

So after some time of this, we found ourselves in the need to also author large ontologies. And yes, Protégé is a nice tool to develop ontologies, but for our use cases, it was just not well suited and we also found it to not scale very well. So we began to implement some simple markups to also allow to also develop ontologies in KnowWE. After then recognizing, that authoring ontologies the 'wiki way' indeed works pretty nicely, we decided to again also share these tools with everybody else on d3web.de. And that is why today you can author/develop both d3web knowledge bases and ontologies in KnowWE, although there is no actual connection/interoperability between both as of now. That would be nice of course and maybe we add this in the future, but for KnowWE is just a development environment for these two knowledge representation.

Maybe you can see KnowWE similar to an IDE like eclipse or IntelliJ, where the same application can be used to develop many different programming languages. KnowWE does the same for different knowledge representations.

A problem is maybe, that historically, we didn't differentiate very well between KnowWE and d3web, because KnowWE was narrowly used to build d3web knowledge bases. We also like to call KnowWE and its distribution package d3web-KnowWE for example. But maybe this should change...

Thanks for pointing this out, I will try to correct/clarify this on d3web.de