Temporary note
I am posting this to demonstrate that this account is associated with btilly@gmail.com. I'll delete it soon, so don't get attached to it.
Random Observations
Latest posts
Why NSA surveillance scares me
Nothing To Hide explains why you should care about surveillance even though you have nothing to hide. But it missed the point that most concerns me. Surveillance states target people who are disliked by the established political order. Starting with politicians who might inconvenience those in charge of surveillance. This distorts the political system in a way that should scare everyone. Here are…
Becoming a web designer
I recently was having a conversation with an art student who wanted a better future than her job as a barista was likely to provide. I suggested a job as a web designer. She had no idea what would be involved, so I promised to talk to a web designer that I knew then get back to her with advice about what it would take. He laid out a very concrete guide to follow for someone starting with an art…
Speculating about the Hyperloop
Elon Musk has been dropping hints about his Hyperloop idea. (We cannot call it a proposal because he has not actually proposed it yet.) There is a lot of curiosity about what it might be. Given Elon's history, the idea will sound audacious and yet will actually be workable. Jacques Mattheij recently speculated on the topic. His proposal has the serious problem in that the friction of the air on…
A/B testing scale cheat sheet
This is not a guide to how to do A/B testing. If you want that, see Effective A/B Testing , or any number of companies that will help you with A/B testing. Instead this is a cheat sheet of basic facts on A/B testing (mostly on the scale involved) to help people who are beginning figure out what is feasible. If you've never tested, expect to find a number of 5-20% wins. In my experience, most…
My son's flashcard routine
My 7 year old son is in grade 2. In the previous grade, despite his intelligence, he was significantly behind his class in handwriting, letter reversals, and spelling. He was getting extra help from his teacher, but he still had an uphill battle. So I decided to start a flashcard routine to assist. This solved the original problem. Here is a description of the current routine, and how it has…
How reliable will the Falcon 9 be?
Let's apply statistics to see, based on current launch data, how reliable we predict that the Falcon 9 will be. Falcon 9 just had a launch that succeeded despite an engine failure. According to design parameters, it should be able to survive the failure of any two engines. But the flight can be lost if we lose 3+ engines. Exactly how reliable is the Falcon 9 design? Let me first take a naive…
A/B Testing vs MAB algorithms - It's complicated
Several months ago, several blog posts appeared on Hacker News comparing A/B testing and multi-armed bandit techniques. If you want to review the posts and the discussion, see 20 lines of code that beat A/B testing every time , then Why multi-armed bandit algorithm is not "better" than A/B testing and finally Why Multi-armed Bandit algorithms are superior to A/B testing (with Math) . I…
Financial stress on the system
I posted this last week on Google+ at https://plus.google.com/u/0/114613808538621741268/posts/13tBzre1nRa. Given market drops since then, I'm reposting it in a more public forum. How could our next financial crisis start? I was in an interesting discussion about this last night. I'd give better than even odds that it will be ugly before Christmas. Here are some of the possibilities to watch. -…
A worst case for the possible US government default
(This is crossposted from Google+. If you use Google+, you scan find the original here .) Lots of people are scared about the possibility of a US government default. But I have an unusual reason that few share. And many might think me crazy for worrying about one of the things that I worry about. So I'd like to share why I think what I do before I confess to my worry. Close to a decade ago I read…
I've switched to Google+
I've been interacting on Google+. You can see my new posts there. The content is different, but includes some content which previously would have appeared here, such as this explanation of homophobia .. Therefore if you were following me here, you may want to try to follow me there instead.
Finding related items
I've mentioned in the past (not in this blog) that C++ programs can beat databases by many, many orders of magnitude. I learned this while doing a specific fun project. I have permission from the company to discuss that project, and here is a description of that project. I was working for a contract for ThisNext . Their database has a large number of records of different items, which a large…
SQL formatting style
I have written considerably more SQL than most programmers have. And after you've written and maintained several hundred line queries, it becomes obvious that SQL is a programming language like any other. Which means that indentation helps comprehension for all the same reasons that it would in any other language. (I'm continually puzzled by programmers who fail to grasp this, and try to put SQL…
How I do Proofs
I was looking through some old papers, and decided to put online some advice that I gave many years ago about how I tackle mathematical proofs. The advice is at How I Do Proofs . This is only lightly edited from the original that I handed out to a course I was teaching in the late 90s. The course is the one I described at Teaching Linear Algebra . I never got any feedback on my request for…
Bluer than blue
On my profile I have answered the question Something I can't find using Google with The lyrics to the version of "Bluer than blue" we sang in highschool jazz. It isn't that you can't find lyrics to the song. The problem is that there are many songs out there with that name, that have unrelated lyrics. Well my question has been answered. Someone who was in my high school jazz choir found my…
Practice poker online for free
I enjoy playing poker. I'm not that good, but I do OK in small home games and I enjoy myself. Recently I've been having a lot of fun playing online for free. How, you ask? Well go to http://www.fulltiltpoker.com/, sign up for free, get a free account, and start playing with play chips. Work your way up to the level you've got skills for, then have fun. Now everyone's first reaction when I tell…
Piaget Water Level Test
Many years ago in a dentist's office I read an interesting article in a magazine. It talked about how there were questions that were specific to certain adult genders. In particular until puberty there was no measurable difference in performance on the question, but after puberty there was a large difference. As examples they offered a verbal question that women do well on, and a question where…
Analysis vs Algebra predicts eating corn?
I like learning about odd connections between disparate things. This probably is the oddest example that I know. Broadly speaking, mathematicians can be divided into those who like analysis, and those who like algebra. The distinction between the two types runs throughout math. Even those who work in areas that are far from analysis or algebra are very aware of the difference between them, and…
How did pterosaurs get so big?
The pterosaurs got going something like 230 million years ago. They died out with the dinosaurs 65 million years ago. Over their history they came in all sizes, from Rhamphorhynchus who was the size of a sparrow to Quetzalcoatlus with a wingspan of variously estimated as being 30-40 feet. Spread out it was a similar size to a t-rex, and on the ground its estimated height was close to a giraffe's.…
Dozenal glyphs - a modest proposal
A proposal that shows up every so often is to use dozenal arithmetic. The idea is simple, in base 12 more fractions work out very conveniently. You can easily divide things 3 and 4 ways. This is frequently convenient, and is why we often sell things in dozens. It is also why the much maligned Imperial system sneaks factors of 3 (3 tsp in a tbsp) and 12 (inches in a foot) in various places. And…
The stock market thinks Microsoft has just under 4 years left
(I posted this basic analysis at http://news.ycombinator.com/item?id=1417156 , which was a discussion of this Newsweek article , and then decided that it was interesting enough to call out for additional attention.) Those of us who pay attention to finance know that the market tends to be more accurate than any individual person. So sometimes it is worth analyzing what the market is saying about…
Le Châtelier's principle: not just for chemists
I seem to be updating my blog once a month or so. I don't intend to do that, I'm just busy. This particular entry is one I've been meaning to write for months, but just haven't gotten around to. But before I get to it, a brief digression. My sister would like to get into a poker tournament that she needs to be voted in to. If you could take a moment and vote for Jennifer Tilly , it would be most…
Random grab bag
I can't believe that it has been nearly a month since my last post. If you've been following me on buzz you'll know that I've been doing a joke a day. I started Feb 18, so now I've gone for 2 months, with a new joke each day, without once having to look one up. I'm surprised by this. Today's joke had a musical component that needed to be heard, so it is on youtube . Stories like this make me sad.…
Touching Women
Today I want to share two useful tidbits about touch and women that I think should be better known, but aren't because people get embarrassed to talk about this stuff. The first is a pressure point to help menstrual cramps. Everyone knows about pinching next to the thumb to help with headaches. It doesn't take the pain away, but it dulls it and makes it more bearable. There is a spot that does…
Address emotions in your forms
I learned quite a few things at SXSW. Many are interesting but potentially useless, such as how unexpectedly interesting the reviews for Tuscan Whole Milk, 1 Gallon, 128 fl oz are. However the one that I found most fascinating, and is relevant to a lot of people, was from the panel that I was on. Kevin Hale, the CEO of Wufoo gave an example from their support form. In the process of trying to fill…