## Happenings – 2010 Sept 18

It is clear that I did not put out a post last weekend, in particular not a first regression post. Well, I tried… but it was still a fairly amorphous collection of ideas…. Today it seems clear that the first post should be about half of what I originally intended… and, furthermore, it looks like I’ll be putting out eight posts about regression.

I wish I could say that eight posts would cover the entire subject, but they will just barely get us started. Besides, while there are some simple aspects of regression that I understand, there is a lot more that I don’t understand.

Still, it is a fascinating subject and I’m looking forward to writing about it. I’ll show you what I understand… and then I’ll tell you all the things I don’t understand yet, that I need to put more time into.

On the face of it, it looks like going to the Highland Games didn’t cost me a post that weekend, but the following weekend instead. In fact, however, the truth is simply that I am fumbling a bit in the transition between subjects.

If the groundwork were already laid, I could post a regression analysis of a particular set of data… but the groundwork is not already laid, and it has taken me a while to sort out just what I want to say.

The only other progress I’ve made is in control theory, specifically “internal model control”. I believe I have confirmed all 15 entries in the relevant table in the Morari & Zafiriou (“Robust Process Control”, 0 13 782153 0). Unfortunately, there are still a couple of entries in Bequette’s Process Control that I haven’t been able to match. I find it particularly frustrating when I can get the right answer only some of the time. (Yes, given how often I’m getting the right answer, I begin to consider the possibility that Bequette is mistaken.)

I have not had time to touch either sensitivity analysis in linear programming, or to organize the material for doing logic by solving Boolean equations.

To top it off, I apparently needed a nap this morning – I fell asleep after breakfast! Well, that was my window for doing group theory this morning… so it probably won’t happen today.

I’ve got a regression post to write.