Airplane Boarding

Yesterday, I posted something about airplane boarding which I pulled immediately because it was just embarrassingly naive. Here's the problem statement in the form of a bad limerick:

On my way to my assigned row,

I was stuck behind a bimbo, 

In the overhead bin she's trying  to stow

A bag weighed at least 50 kilos.

That's just the beginning of my woes, 

A passenger I didn't even know,

Struggling to his seat by the window, 

Put all his weight on my poor little toe.

Wouldn't it be better if we go,

LIFO instead of FIFO?

At first glance, I thought a Last In First Out (LIFO) boarding order, i.e., back-to-front, window-to-aisle, would be the most efficient. if we board the plane in the reverse order of how we deplane (which is naturally front-to-back, aisle-to-window), significant time can be saved.

Turns out there are papers published on this very subject, all schemes work about the same and random boarding is actually the quickest in simulation and real life. Any kind of zone/group boarding creates localized congestion which cancels out the benefits. This is not too surprising because we see this in engineering all the time, for example, we haven't been able to improve on the efficiency of Ethernet which uses random timing.

Here's a link to one of the studies from University of Colorado, they have pretty cool simulation of different boarding schemes that you can play and watch.

Next time when you're caught boarding the plane before your zone is called, you can sincerely explain to the airline staff that you're just trying to improve efficiency, they found the cheaters (about 10%) do make the zone boarding process slightly faster in another study.

Fish Galore

Green Steel, you da man!

Red snapper galore

                                                                    Bait fish galore

Beer galore

Pussy Galore (played by Honor Blackman) 

My Favorite Bicycle - Jamis Sputnik fixie

I have a lot of bicycles. Above all, I like American bikes, I have a Fat City Yo! Eddy, a Schwinn Paramount, a classic Trek tourer, and an Ibis mountain bike. The problem with having many bikes is keeping the tires all pumped up, if there's a bike in the herd that's always ready to go, it's my Jamis Sputnik fixie. Fittingly, "Спутник" mean travel companion in Russian.

Sputnik posing suggestively in Boston

Jamis doesn't have any pedigree to speak of, the name is supposed to be French, most people just say "jay-mis" instead of the proper French pronunciation which is de rigueur  for real European brands. Jamis bikes are often middle of the road, made in China, "high value" models, yet the Sputnik is such a simple, purposeful looking bike that I couldn't resist when I first saw it in Simple Living Cycles in Framingham. Phil, the proprietor, runs a messy bike shop, he hates Shimano for its virtual monopoly and their unnecessary innovations such that much of his small shop is devoted to single speed and fixed gear bikes. It was also a good price, I paid less than $500 for a bike retailed for more than $700 in 2007.

A fixed gear bike, or a fixie, is just a track bike ridden on the street. Like real track bikes, the Sputnik doesn't come with  brakes (you stop a track bike with your legs), the bottom bracket is higher than normal (so you can keep pedalling through a corner) and is made of Reynolds 631 steel (good stuff). I put front brakes on mine for safety reason, not to mention my bike handling is just not good enough to ride brakeless in traffic like some bike messengers (rear brakes are not essential on a fixie, actually, rear brakes don't do much on any bike because most of the stopping power comes from the front).

It takes a few rides to get used to not freewheeling, whenever you try to coast, the pedals would keep turning forcefully and you feel like you're getting pushed off the bike violently. But surprisingly, I hardly miss the gears, the bike is currently geared at 42x16 (lowish) and I can take New England rolling hills without stressing my knees too much. I spin out at just around 30 miles per hour, so going downhill is hard work twiddling wildly at 140 RPM and I use the front brakes to slow down when my legs can't keep up..

I estimate I have 5,000, mostly commuting miles on the bike. Here's some of my thoughts:
-  Great frame, I have a Trek with Reynolds 531 steel frame which feels harsh in comparison. This 54 cm Reynolds 631 frame, TIG welded in in Taiwan, is one of the most comfortable bicycles I have ridden,  The wide 44cm handlebar helps also.
-  It's quite reliable because there's little to break to begin with. I rode through winters and it was virtually maintenance free (=neglect) for the first 3,000 miles. When I finally decided to clean the bike after the 2nd winter, I discovered it was missing 2 chainring teeth and one cog tooth, the entire drive train basically went south after 4,000 miles.
- So far I have replaced:
  Bottom bracket twice (once with the crankset)
  Crank arms (caused by loose pedals, my fault)
  Chainring
  Cog
  Chain
  Headset
  On 3rd set of tires.
  The fancy Brooks Swift saddle upgrade (at around mile 2,000) works OK, I like it but it's not a day and night difference compared to the original saddle.
  1990ish small Shimano Ultegra SPD road pedals are OK. I know it's silly to have clipless pedal on a fixie   but I like road shoes that I can walk in. The pedals are holding up well but look horrible, both the pedals and the cleats need some lube once in a while to disengage cleanly.
- Clip on fenders are great, you must have fenders for commuting, and there's no eyelets on the frame.
- Original wheels are still true, no maintenance required.
- Track bike riders are obsessed with chain line, I stopped paying attention to it after the 1st component change.
- Winter riding in Boston is no problem up to an hour, beyond one hour, nothing works. Less than 10 days a year is not ride-able.
- Messenger bags are not waterproof, I can only rely on my Ortlieb backpack to keep my laptop and cell phone dry.
- Bicycling is roughly as costly as driving. Assume my total investment was $1,000 over 5,000 miles, it comes to 20 cents a mile not counting the extra food consumption.

Fixies are popular among hipsters. I knew about the Beatniks and Hipsters of the 40s but had to wiki for the new meaning of "hipster". Regardless, I am at a point trendiness doesn't bother me one way or another, how funny how one has to conform to the non-conformist culture to be one.  I was interested in fixed gear bikes because of the late Sheldon Brown (bicycle guru) and the bike messengers. In Hong Kong, fixed gear bikes are called 梗牙. a most charming Cantonese term meaning jammed/stuck teeth.