Sunday, May 19, 2013

"A random tour through some scaling laws"

"This, of course, is where the mystery of the game of dimensional analysis [pdf] lies: which variables should be invited to the party?" 

One of the references is Scaling (Cambridge Texts in Applied Mathematics) by Grigory Isaakovich Barenblatt. A more accessible introduction might be Dimensional Analysis and Intelligent Experimentation.

11 comments:

John said...

I didn't know dimensional analysis is such a big topic that you can write books on it.

I haven't read anything of those texts. Just a quick and naive thought: This reminds me type systems in computer science. (Dimensions in real world are types in computer programs.) And Curry–Howard isomorphism shows type checking is equivalent to theorem proofing. Maybe here is another isomorphism that links dimensional analysis in real world to theorem proofing in mathematical logic.

CP said...

Never heard of type systems - thanks.

You've been a good commenter around here. What's your story? What do you own right now?

John said...

I live in Australia. My formal training is in computer science. Once upon a time I wanted to do a PhD in that area. (Type systems and programming language design are precisely the research topics I was and am interested in!) But I eventually discovered Buffett/Graham and found investing is more fun, more meaningful and equally challenging intellectually.

I have a daytime job. I manage my extended family's money in my spare time.

Given my background, I'm comfortable with technological stocks. I current own AAPL, DLB, BBRY and GLW. At the micro end, I have CNRD and SODI. I also have some DAR and RGS. Needless to say, CNRD is my biggest position.

How about your? What's you story and what do you own?

CP said...

I'm surprised to have a reader who owns Apple!

I have looked at SODI - I was quite skeptical about the accounts but it looks like the credulous may have been correct on that one.

Still really like CNRD.

CP said...

Was just reading this old post because I was thinking about scaling.

John, what's new with you?

CP said...

Wow, this was exactly a year ago.

Looks like you made money on APPL but lost on BBRY. Curious that you owned both.

I would think that the profit from mobile handsets is fixed or even declining (even as output is growing). Why would you want to own more than one maker?

John said...

Hi,

I still own both AAPL and BBRY. My BBRY stake is much smaller. But I can't deny BBRY was a mistake. I misjudged the management. The value in BBRY is not the handset business. It's in the BES servers. The previous management mishandled the transition of the business. I saw some red flags but gave them the benefit of doubt. I still think it has a good chance to be a leaner company profitable from BES.

I still think AAPL is very undervalued.

I've sold down my CNRD.

Interested to hear what stocks you like these days.

CP said...

Thanks for writing.

You basically mean putting the Blackberry business in runoff and not trying to develop an answer to the iphone?

I don't think you can get a management to ever do that.

CP said...

Not much I *like*. There's a lot I dislike and think is going to zero.

I really like treasuries and especially munis.

CP said...

P.S. Enjoy your comments, I hope you keep commenting on the blog.

John said...

You are welcome.

Although I don't short, I've learned a lot interesting things from your blog.

Regarding BBRY, BB phones will become a niche. Its dev cost will be subsidised by cash flow from BES.