## Happenings – 2012 Jun 9

It’s been a really slow week.

There have been a couple of earthquakes (3.6 and 2.9)… the 1st about 15 miles from San Jose… the 2nd under the ocean about 30 miles west of San Francisco City Hall. This is 2 so far in June. I’m still surprised at how rare magnitude 2.5 events are in my neighborhood, on the order of 10 per month.

I’ve ordered and received 3 more books… about filter banks and/or wavelets. Yes, I’ve been playing with wavelets in Mathematica® version 8 – but I’ve already seen one answer that completely bewilders me. I’m sure one of us did something wrong – but is it me or is it Mathematica? (I actually hope it’s me… because me I can fix, in time.)

The books were…
Fundamentals of Wavelets… Goswami and Chan, 2nd ed, Wiley 978-0-470-48412-5.
Digital Signal Processing… Diniz, da Silva, and Netto, 2nd ed, Cambridge 978-0-521-88775-5.
Multirate Digital Signal Processing, Crochiere and Rabiner, Prentice-Hall 0-13-605162-6.

Oh, I also noticed that the classic “Wavelets and Subband Coding” by Vetterli and Kovacevic is now available from Dover… I had to track down a used copy, a few years ago.

I’ve got a post – the first of two about the assumptions underlying the analysis of a regression fit – nearing the end of stage III… so most of the mathematics is done, but not all of it. There’s just one piece to figure out how to describe. Perhaps surprisingly, it’s the expected value of the sum of squared errors – it’s tricky to compute, and I haven’t decided how to present the things we need for it. I know them – but just how do I want to introduce them?

(Not only do I hate reading solutions that come out of left field, I hate writing them, too.)

I’m beginning to wonder if I need a break. I’m struggling just to get the blog posts out, and I don’t seem to have much energy for any other mathematics. And that feels terrible, it really does.

And with that, let me see what mathematics I can get done today.