Hacker News: fraserphysics

New comment by fraserphysics in "What happens to an economy when it's too hot to work?"

fraserphysics — Sun, 14 Jun 2026 01:49:18 +0000

The second law of thermodynamics implies that one must spend energy as work to move thermal energy up a temperature difference. So the net effect of an air conditioner is to increase the total amount of thermal energy.

New comment by fraserphysics in "The Countdown to a Major Oil Price Surge Has Begun"

fraserphysics — Wed, 10 Jun 2026 03:52:39 +0000

For a long time I've been reading that the closure of Hormuz is going to constrain consumption soon. I understand the economic theory that reducing supply of an inelastic commodity greatly increases the price. The article says that inventories have insulated us from high prices so far. I am surprised by how large and effective those inventories have been. And I am surprised that futures prices are not higher. Can anyone here suggest explanations?

New comment by fraserphysics in "I'm skeptical about efforts to revolutionize schooling"

fraserphysics — Fri, 05 Jun 2026 13:58:33 +0000

It was so long ago that I've forgotten most of it. I was impressed that it was based on evidence based literature. Here is a link to the training now https://carpentries.org/instructor-training/ I am disappointed that I don't see a reading list.

Unless it's changed since I was active, The Carpentries does not monetize content.

New comment by fraserphysics in "I'm skeptical about efforts to revolutionize schooling"

fraserphysics — Fri, 05 Jun 2026 02:04:54 +0000

I signed up for software carpentry instructor training at the SciPy conference in 2015. I expected to learn about their curriculum. Instead, I found that they taught pedagogy. There were articles to read in advance. I should have taken that class before I spent 15 years teaching at university rather than afterwards.

New comment by fraserphysics in "FBI Arrests CIA Official with $40M in Gold Bars in His Home"

fraserphysics — Thu, 28 May 2026 16:33:53 +0000

When I worked at Los Alamos, the head of counterintelligence was a former CIA ops guy. He seemed warm and intelligent; just an all around good guy. In presentations, he explained that his job at the CIA was to exploit that appearance to ruin people's lives. He said his approach was to gain the trust of a mark, and then provide him with what ever was required to get him to betray things he loved. The presentations were effective, enlightening and spooky.

So, I agree: All spies are bastards.

New comment by fraserphysics in "The Letter S, by Donald Knuth (1980) [pdf]"

fraserphysics — Thu, 21 May 2026 04:41:08 +0000

This article was in Springer's The Mathematical Intelligencer in 1980. The next article in that volume was "Strange Attractors" by David Ruelle. When I read Ruelle's article in the early 1980s, I noticed Knuth's article. By the time I got to writing my third paper on strange attractors in 1988, I was using TeX.

New comment by fraserphysics in "Helium Is Hard to Replace"

fraserphysics — Fri, 10 Apr 2026 22:05:24 +0000

Helium will leak out of some structures that hold methane. Shale will trap methane and let helium escape. Layers of salt trap both. Thus horizontal drilling and fracking to recover oil and methane from shale produces very little helium.

New comment by fraserphysics in "Tracy Kidder has died"

fraserphysics — Tue, 31 Mar 2026 19:35:41 +0000

Tracy Kidder's father and grandfather (Henry M. and Henry M. Jr.) were partners in the law firm that's now Seward and Kissel. My great grandfather was a partner in the firm when he died in 1935. I've heard that everyone liked and admired my great grandfather. The Kidders took care of his descendants for the next say 65 years. In 1977 when I got a Bachelors degree in Physics, HMK Jr. wrote a will for me. We met at the Seward and Kissel office to get it signed and notarized, and HMK Jr. took me to lunch at a fancy club downtown. After some martinis, he told me that there'd been two generations of losers in my family, and that everyone thought with my degree in Physics, I could pick up the mantle.

Then he said that he wished his son, Tracy, had an interest in real science like me. When I asked what Tracy was doing, Henry described a silly project of hanging out with computer engineers.

I enjoyed "The Soul of a New Machine" when it came out. I always hoped that I could meet Tracy someday. I guess not. He did great work, I hope his father learned to be proud.

New comment by fraserphysics in "Epstein's Ugly World of Science"

fraserphysics — Sat, 14 Feb 2026 16:25:31 +0000

Thank you for articulately describing an ugly part of the world of science that I've seen over the last 40 years. I appreciate your "There but for the grace of God" thought. If I were a bigger star, I can only hope that I would have behaved better than some of those big stars.

New comment by fraserphysics in "The AI boom is causing shortages everywhere else"

fraserphysics — Sun, 08 Feb 2026 17:03:59 +0000

After free UNIX and Linux became available on affordable home computers, I found it was no longer necessary to be at a company to do interesting projects. That was before 1995.

New comment by fraserphysics in "Quickemu: Quickly create and run optimised Windows, macOS and Linux VMs"

fraserphysics — Sat, 03 Jan 2026 03:35:28 +0000

Encouraged by the replies here, I tried to get quickemu to setup macOS on my AMD based desktop. The emulated machine crashed trying to boot macOS, and I gave up after a couple of hours.

New comment by fraserphysics in "Quickemu: Quickly create and run optimised Windows, macOS and Linux VMs"

fraserphysics — Thu, 01 Jan 2026 20:48:01 +0000

I thought that macOS was proprietary, and that apple only allowed it to be run on apple hardware. Just last month, I used incus to test a software package in 6 Linux distributions. I want to also test the package in macOS. Must I get a license from apple to do that with Quickemu?

New comment by fraserphysics in "Ask HN: What Are You Working On? (December 2025)"

fraserphysics — Sun, 14 Dec 2025 21:26:59 +0000

I'm polishing up the second edition of "Hidden Markov Models and Dynamical Systems." The book explains several state space models and connects them to ideas about chaos. Here's a link to a pdf draft: https://www.fraserphysics.com/book.pdf and here's a link to source for the book: https://gitlab.com/fraserphysics/hmmds Once you install the source software, you can build a pdf for the book by typing "make book". I think that makes it reproducible research.

Show HN: Markov Models and Dynamical Systems – Software and Book

fraserphysics — Fri, 21 Nov 2025 16:42:20 +0000

This is a draft of a second edition of this book from SIAM https://epubs.siam.org/doi/book/10.1137/1.9780898717747?mobi...

There are three things to show:

1. A pdf of the draft: https://www.fraserphysics.com/book.pdf

2. The hmm project which provides code for state-space models: https://gitlab.com/fraserphysics/hmm with documentation at https://fraserphysics.gitlab.io/hmm/

3. The hmmds project which provides code for using state-space models to address some examples: https://gitlab.com/fraserphysics/hmmds with doumentation at https://fraserphysics.gitlab.io/hmmds/ The default target for hmmds is to build the book. On my home system it takes about 10 hours to build the book.

I would be grateful for comments or suggestions on any aspect of any of the three things.

I am particularly interested in help with the following:

1. I use NixOS for developing. I've documented progress on making the code useful in other enviroments at https://fraserphysics.gitlab.io/hmmds/getting_started.html Please let me know if you are able to use the code elsewhere.

2. In the draft of the book, I have an analysis of the convergence properties of the EM algorithm spread between Section 2.5 "The EM algorithm" on page 43 and Appendix B "EM Convergence Rate" on page 137. The analysis is different from anything I've seen published. I would like feedback with corrections and or citations.

Comments URL: https://news.ycombinator.com/item?id=46006083

Points: 4

# Comments: 0

New comment by fraserphysics in "$50 Oil Could Crush American Shale Growth"

fraserphysics — Wed, 05 Nov 2025 01:17:01 +0000

Yes! There's more oil in the ground than we should ever burn. The places where it's cheap to get out are ruled by unpleasant people. Shale limits the price they can charge. Yea shale. However, low prices encourage putting CO2 in the air. Boo shale. I wish we would find a better way to reduce use than paying unpleasant people high prices.

New comment by fraserphysics in "Nobel Prize in Physics 2025"

fraserphysics — Tue, 07 Oct 2025 17:37:19 +0000

I read the NY Times article about this earlier this morning. I thought it was not very good. I came to HN to see if it had something better. It did. The linked article is also at something like a high school level, but it gave me (retired PhD Physics) a good idea of the experiment and the theory. Thanks.

New comment by fraserphysics in "Random Attractors – Found using Lyapunov Exponents (2001)"

fraserphysics — Wed, 01 Oct 2025 00:06:30 +0000

Please take a look at the most recent draft of my book "Hidden Markov Models and Dynamical Systems" https://www.fraserphysics.com/book.pdf In the first chapter I talk about a chaotic model for laser dynamics, and in the last chapter I use the same ideas to analyze ECGs.

The code and text are at https://gitlab.com/fraserphysics/hmmds. From a Nix command line, "make book" builds the book in about 10 hours.

I'd be grateful for any feedback on the book or the software.

New comment by fraserphysics in "A human-accelerated neuron type potentially underlying autism in humans"

fraserphysics — Mon, 29 Sep 2025 04:55:26 +0000

I think it was Larry Summers.

New comment by fraserphysics in "Google's Liquid Cooling"

fraserphysics — Mon, 25 Aug 2025 19:20:59 +0000

One way to characterize the cost of cooling is entropy production. As you say, cooling is proportional to difference in temperature. However, entropy production is also proportional to temperature difference. It's not my field, but it looks like an interesting challenge to optimize competing objectives.

New comment by fraserphysics in "Why Hasn't Medical Science Cured Chronic Headaches?"

fraserphysics — Thu, 14 Aug 2025 05:54:08 +0000

I started getting migraines in the 1960s. Thanks for the link.

While a cup of coffee often helped me feel better in years past, I've found eliminating coffee from my diet has reduced my headache frequency. Triptans help when I get the occasional headache now.

I was disappointed that the article didn't talk about the variety of migraine manifestations. Some of the manifestations can be confused with transient ischemic attacks.