Physics Joke
Apr. 26th, 2011 08:40 amA Higgs-Boson particle walks into a church and the priest says, "you can't be here." And the particle says, "but without me you can't have mass!"
Thanks,
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Portal 2 quibbles
Apr. 25th, 2011 01:11 pmI played it and was amused, but it left me with a couple unsettled thoughts:
( assumes knowledge of the whole game plot )
The actual game play and new puzzles were pretty nifty and well done, and all the art and architecture are quite impressive and pretty too.
( assumes knowledge of the whole game plot )
The actual game play and new puzzles were pretty nifty and well done, and all the art and architecture are quite impressive and pretty too.
1000km on electric power
Apr. 22nd, 2011 06:07 pm
The batteries don't do well in cold. Below 40F the performance is noticeably worse for acceleration and hill climbing and top speed sustaining.
I take my charger to work, and charge the batteries (they have to be removed from the scooter to charge) in the office. It's supposed to have 40 mile range, but now I suspect that to be some engineering ideal on a flat stretch without stopping. In the cold with traffic and hills it can feel sluggish around the end of the 10 mile ride between home and work. The longest I've done in one charge is 20 miles, and at the end of that was some slow going with sluggish acceleration and I couldn't really get it over 20 mph. But even at the best of times there are hills on my commute that I can't do over 20 mph, and on often only 15 mph.
I always ride with one eye on the gauges. The battery gauge shows me how hard I'm taxing the system while accelerating or going up hills. I think if I keep that moderate I can get better economy and range out of it. I'm pretty sure that the first weekend I had it and took it out I ran out of battery because I was riding it too hard. I haven't run out since (it does have a cutoff dead end), just run down to go slower.
Still, the fuel cost per mile is low (about one or two cents), the device new was cheaper than most cars I could get, and it's faster than biking or bus. I'm gonna keep calling this experiment a qualified win. If it gets to 10,000km it'll definitely be a win.
Boston tech geek event
Apr. 8th, 2011 03:49 pmIt's time again for Bar Camp Boston, one of my favorite tech-geek gatherings. This Saturday/Sunday, 9ish-6ish both days, this time at the Microsoft offices in the Kendall Sq area.
car efficiency
Mar. 14th, 2011 01:46 pmI made a simple spreadsheet showing economy of cars at $3.50/gal, comparing Prius and Insight hybrids and a standard Fit.
You need either a lot of miles or really expensive gas to make the added cost pay for itself.
Of course there may also be other features between these cars. Maybe the high end is also to be nicer for people who want to pay for nice, and the low end is the budget model for people without that cash. There's some test-driving to be done.
You need either a lot of miles or really expensive gas to make the added cost pay for itself.
Of course there may also be other features between these cars. Maybe the high end is also to be nicer for people who want to pay for nice, and the low end is the budget model for people without that cash. There's some test-driving to be done.
Probably gonna buy a car between now and August. The $24000 for a new 2011 Prius is starting to sound reasonable. The pure-electric cars aren't available and have lame range*. The Chevy Volt is too expensive. Other hybrids get lesser efficiency and aren't as nice.
Also, I realize I shop for cars like I shop for gadgets. Lots of window shopping on websites and pricing out packages and features. Toyota's configuration page falls somewhere between Apple's (easy) and Dell's (way too much crap and way too long). But I'm definitely not going to be picking out a case-motherboard-cpu-etc and assembling them myself or whatever the equivalent would be in car land.
* Energy. 1 gallon of gasoline has 115000 Btu of chemical heat energy, at perfect energy conversion that would be 33.7 kilowatt-hours. We could cut that in a third as a rough estimate of energy conversion for an internal combustion engine. The Nissan Leaf and Ford Focus Electric have 21-23 kilowatt-hour batteries. If that's 2 post-conversion gallons of gasoline (a pretty small tank) and they have a range of 100 miles, they get about 50 miles per gallon. I'd call that normal for an efficient car these days. Now we just need batteries with the energy density of gasoline. Also, five miles per kilowatt-hour is about the same as my electric scooter gets.
Also, I realize I shop for cars like I shop for gadgets. Lots of window shopping on websites and pricing out packages and features. Toyota's configuration page falls somewhere between Apple's (easy) and Dell's (way too much crap and way too long). But I'm definitely not going to be picking out a case-motherboard-cpu-etc and assembling them myself or whatever the equivalent would be in car land.
* Energy. 1 gallon of gasoline has 115000 Btu of chemical heat energy, at perfect energy conversion that would be 33.7 kilowatt-hours. We could cut that in a third as a rough estimate of energy conversion for an internal combustion engine. The Nissan Leaf and Ford Focus Electric have 21-23 kilowatt-hour batteries. If that's 2 post-conversion gallons of gasoline (a pretty small tank) and they have a range of 100 miles, they get about 50 miles per gallon. I'd call that normal for an efficient car these days. Now we just need batteries with the energy density of gasoline. Also, five miles per kilowatt-hour is about the same as my electric scooter gets.
the smallest way to store data
Mar. 11th, 2011 03:13 pmis not to store it at all.
A unique id for a US Census block winds up being 15 decimal digits, which fits handily into an 8 byte int.
Actually there are less than 10,000,000 blocks in the US, so that could easily be a 32 bit number.
But if what I really want to do is store a mapping from each block to district number for each block (easily a 1 byte number), the smallest way to store this is just a list of district numbers. Use the Census data file as a canonical ordering of the blocks.
CSV for this becomes 15 decimal digits, comma, one to three decimal digits, newline. 20 bytes vs 1.
For the hundreds of thousands of blocks in Texas, after gzipping the CSV, this is a 2372 KB file. gzipped byte list is 32 KB.
Sadly, a CSV file in a .zip archive seems to be the common interchange format for these things.
At least I get to use my format between my client and my server.
A unique id for a US Census block winds up being 15 decimal digits, which fits handily into an 8 byte int.
Actually there are less than 10,000,000 blocks in the US, so that could easily be a 32 bit number.
But if what I really want to do is store a mapping from each block to district number for each block (easily a 1 byte number), the smallest way to store this is just a list of district numbers. Use the Census data file as a canonical ordering of the blocks.
CSV for this becomes 15 decimal digits, comma, one to three decimal digits, newline. 20 bytes vs 1.
For the hundreds of thousands of blocks in Texas, after gzipping the CSV, this is a 2372 KB file. gzipped byte list is 32 KB.
Sadly, a CSV file in a .zip archive seems to be the common interchange format for these things.
At least I get to use my format between my client and my server.
Apple XCode
Mar. 9th, 2011 04:13 pmI have enjoyed 10 years of good development tools for free from Apple, and it has been good to use them and make nifty things and evangelize how great developing on Mac is. Today they announced the next version of the tools, available today, cost at least $5. My sense of entitlement, built up over 10 years of expectations, is sad.
where I've been map
Mar. 1st, 2011 12:17 amthis seems to be going around

visited 29 states (58%)
Create your own visited map of The United States
There's also an option for other countries, but it's just USA and New Zealand for me. My parents were wandering around Europe when I was tiny and don't remember any of it, doesn't count. Niagra Falls doesn't really count as having been to Canada either, apparently.
visited 29 states (58%)
Create your own visited map of The United States
There's also an option for other countries, but it's just USA and New Zealand for me. My parents were wandering around Europe when I was tiny and don't remember any of it, doesn't count. Niagra Falls doesn't really count as having been to Canada either, apparently.
cpu geekery
Feb. 28th, 2011 01:17 amAmazing. New MBP 15 with the 2.0 GHz i7 gets faster single thread execution than my MBP13 2.53 GHz Core 2 Duo from June 2009. (about 20%-30%) And the new chip has 4 cores instead of 2. Good job, Intel. Now I have something to look forward to again, maybe on the next iProduct cycle.
Methodology: walk into an apple store and run http://bolson.org/flops_js/ on the new machine and compare to what mine gets.
Methodology: walk into an apple store and run http://bolson.org/flops_js/ on the new machine and compare to what mine gets.
Firefly epiphany
Feb. 26th, 2011 11:10 amMaybe this is old news to other fans...
( you have all seen Buffy, Firefly, and Dollhouse, right? )
( you have all seen Buffy, Firefly, and Dollhouse, right? )
Help me compute redistricting
Feb. 21st, 2011 12:49 pmHere it is, the place to download the client for Linux and MacOS (x86_64 only right now):
http://bdistricting.com/client/
It's not nice, it needs to be run from a terminal command line, it might take a couple minutes to set up, and it might not even work on some systems, if so, any email with bug reports and comments would be welcome.
Also, my own little compute farm (a core i7 linux box and a pair of core 2 duo Macs) now has results for many of the states that data is currently out for. The latest results always at
http://bdistricting.com/latest/
Cross posted from my redistricting blog:
http://blog.bdistricting.com/2011/02/help-me-compute.html
http://bdistricting.com/client/
It's not nice, it needs to be run from a terminal command line, it might take a couple minutes to set up, and it might not even work on some systems, if so, any email with bug reports and comments would be welcome.
Also, my own little compute farm (a core i7 linux box and a pair of core 2 duo Macs) now has results for many of the states that data is currently out for. The latest results always at
http://bdistricting.com/latest/
Cross posted from my redistricting blog:
http://blog.bdistricting.com/2011/02/help-me-compute.html
(no subject)
Feb. 18th, 2011 09:06 pmI have a long weekend (monday off) and no plans. Anything I should know about? I guess by default I'll be hacking on bdistricting.com from home or coffeeshop.