Have You Implemented Backward Chaining On A Microsoft Rule Engine?

January 11, 2010

Every so often I hear about a “friend of a friend” who has implemented a backward chaining project with one of the Microsoft rule engines (WF Rules, BizTalk MS BRE). However, the details usually fail to materialize. If you have worked on such a system, or know someone who has – please contact me using the contact form on this blog. I’m interested in understanding more about your project and how successfully the backward chaining implementation went.

(As always – this is mainly personal interest, and does not reflect on any future directions of my employer’s products.)

7 Comments | .NET, AI, Microsoft, rules | Tagged: , , , , , , , , | Permalink
Posted by Karl W. Reinsch

On Chaining

January 7, 2010

One of the recurring topics in the rules world is forward chaining vs. backward chaining – how they compare, when to use one or the other, and which implementations even offer back chaining. I suspect that a lot of the confusion around backward chaining is simply due to the fact that most folks haven’t implemented production-quality systems that make use of it.

One of the forward vs. backward articles is by Dietrich Kappe. In his posting, he includes a quote from Charles Forgy, including the following:

Backward chaining systems are more limited than forward chaining systems.

Dietrich points out that the article was located on the old Rulespower site and disappeared with the purchase by Fair Isaac.

I’m posting here simply to point out that the Wayback Machine has them.

Charles Forgy on Forward and Backward Chaining

I have linked directly to the latest archived version of each article segment. You can find all the RulesPower content that they have here.

For further reading on the topic, the discussions at the following links are interesting (in no particular order):

1 Comment | AI, rules | Tagged: , , , , , , , | Permalink
Posted by Karl W. Reinsch

Who Said It? “any backward chaining engine must eventually…”

January 7, 2010

I found a quote that James Owen used on the JESS mailing list and I’m interested in learning where it comes from. More specifically, is it in a paper or article somewhere and I’m just overlooking it? My suspicion is that James is quoting Dr. Charles Forgy and that it isn’t published in any articles.

I’ll email James to check the source – but I wanted to highlight the quote here since it was only used on the JESS list and could use a little more exposure.

“Any forward chaining engine can be made to do backward chaining and any backward chaining engine must eventually forward chain to deliver results.”

Updated on January 13, 2010:
James has confirmed (via email) that he was paraphrasing Dr. Charles Forgy here. The comment apparently was made during OPSJ training classes.

No Comments » | AI, rules | Tagged: , , , , | Permalink
Posted by Karl W. Reinsch

Rules Research Archaeology

January 7, 2010

Most readers should be familiar with George Santayana‘s quote about remembering the past (also called Santayana’s Law of Repetitive Consequences).

The rise of the BRMS over the last few years has brought lots of enthusiastic new members to our little rules world. These people are eager to contribute to the field and make their own mark. It is the job of the “old guard” to make sure the newcomers are properly aware of the prior research in our field. (Having only participated in the space since 1995, I consider myself to still be a newcomer.) For example, the rise of the multi-core processor means that tons of older research in parallel rule engines is of interest and relevant. For another example, the classic work on conflict resolution strategies doesn’t appear to be online and is in a long out-of-print 30-year-old book. (And at least the prices for “Pattern-Directed Inference Systems” are somewhat affordable – as of this writing, “Human Problem Solving” starts at $190 and goes up to $800 on Amazon.) A third example is that the Wikipedia article on the Rete algorithm only has references to papers that are not online for one reason or another. (I personally haven’t even seen the “A network match routine for production systems.” working paper.)

Thus, I would like to highlight a few useful resources:

We need to work together as a group to improve the online availability of our history.

No Comments » | AI, rules | Tagged: , , , , , , , , , | Permalink
Posted by Karl W. Reinsch