Saturday, October 03, 2015

VW and the dark side of AI

When I heard VW got caught cheating on emissions tests, I was not surprised.

What was surprising is that I could smell french fries every time a coworker drove by in her 'clean' diesel VW bug running on biodiesel (a mixture of diesel and filtered used fryer oil from restaurants.)

How could the emissions from her car be clean if the aromatic chemicals that give off the characteristic french fry smell were not combusted beyond recognition?  How could such incomplete combustion pass the strict California emissions tests?

How did VW game emissions testing?

This Computer World article gave a log of possibilities but no definitive answer.
Arvind Thiruvengadam, a research assistant professor at West Virginia University, was involved in a project last year that evaluated tailpipe emissions of diesel cars made by European manufacturers for the American market.
Thiruvengadam said he hasn't researched the software that allowed Volkswagen to cheat on the tests. But he did say "there were lots of ways an electronic control unit could be programmed to identify testing and change its fuel mapping toward low emission in those rare scenarios."

For example, modern cars can sense when a hood is open for dynamometer testing, "so a smart hood switch could double as a defeat device."

Or, another sensor could detect when a vehicle's traction control unit was disabled, which is required during emissions testing, and place the emission system into a different mode.

"The possibilities are almost endless," he told Autoblog. "I'm pretty sure that if you're one of the largest car manufacturers, you could do a lot more."
Some of these methods could produce false positives--assume they are being tested when they are actually being driven on the road.

For instance, if the motor is running but the car is not being actively steered, can you assume the car is on rollers for a test?  What if the car is instead being driven on a straight desert road?

In that case, switching the car to 'clean' mode would drastically reduce the fuel efficiency and the car could run out of fuel in a remote location.  If many VW owners report the same problem when driving straight, often remote, roads, the gig would be up.

My aha! moment came when one article said the method involved steering, engine use, AND pressure sensor data.

According to the US EPA violation letter to VW, sensors that could be used in a 'defeat device' need to be disclosed along with the reason why the device is needed for a non-defeat purpose.

I could imagine pressure sensors being useful for a fuel injection system or a rough altimeter, but not while the car was in motion.  Other methods would work better due to Bernoulli's Principle.  So why would VW put pressure sensors in their cars?

A moving car is shaped a little bit like a wedge or an airplane wing.  The air above the car moves slightly faster than the air that flows below the car; Bernoulli's principle states that pressure exerted by a fluid decreases as the fluid velocity increases.

If the motor is running for many minutes without active steering AND the pressure sensor on top of the car does not drop, then the car is likely on rollers in an emissions lab.

Artificial intelligence, AI, in your car determines when to apply the ABS brakes, traction control and the ratio of air to fuel.  It can also be used to cheat on emissions tests.

How can we find a simple algorithm like this--that can be written in just a few lines--among the 100 million lines of code in some new cars?

The Upshot in the NYT answered (or tried to answer) Little Hunting Creek's question of excess mortality due to VW emissions.

Wednesday, September 30, 2015

Sunday, September 27, 2015

Burda 8984 Refashion

Remember those two thrifted XL T-shirts in their original state?
One of two thrifted shirts perfectly color-matched to the skirt.
When Burda first started selling paper patterns in the US with seam allowances, a sewing friend raved about this pattern.  I bought it.  At ~20 years, is this pattern OOP or Vintage?
I used scraps of black jersey from another project for facings.
One of the sleeves is pieced.
All hems were preserved and reused so that I didn't have to break out the twin needle this time.
Refashion chic outfit.
While sewing, I was very impressed with the accuracy of the draft for the shoulders, neck and sleeves. I'll update this post with fit notes after the DD tries it on.

Friday, September 25, 2015


I saw this real estate agency door in my old neighborhood* and realized that Boulder is soooo over. Look at the list of places that are now playgrounds of the extremely rich.

I am especially sad about Boulder and Monrovia because they are towns where scientists who worked at CU/NOAA/NIST/NCAR/JPL/Caltech used to live, but can't afford now.

When scientists at national labs can't afford to live close to work, we scatter to the four winds and no longer run into each other outside of work.

When something breaks down in lab, it's hard to pop in to fix it on weekends and evenings if you live far away.  Alternatively, you could stay in lab more and never see your family.

We as a society have decided to pay scientists a lot less than similarly trained professionals and consigned scientists to a financially precarious life.  We're not as badly off as artists financially**, but the trend is worrisome.

* I lived on West Pearl back when it was inhabited by graduate students and winos.  My roommate at the time, a PhD candidate in human geography, said that we were the shock troops of gentrification.  She was so, so right.

** Artists do have more freedom to move to cheaper places, but scientists need to work in labs in places like Boulder and Palo Alto.  Then there is the two-body problem of finding two science jobs in the same locale when scientists marry one another.  This is a severe problem.  I read one survey that uncovered that 80% of female PhD physical scientists are married to another physical scientist or an electrical engineer.

Wednesday, September 23, 2015

Monday, September 21, 2015

Quick T-shirt refashion

I spent the weekend at the Jaipur Literature Festival instead of sewing or doing housework.  I'm spending my evening hours getting caught up with general housework.

I'll show a refashion from last month.
During the mild days of Fall, I often wear t-shirts layered under shirts or light-weight cardigans.  I can make my own plain t-shirts, but it's much easier to purchase them from thrift stores ($1 each) and customize the fit.

If a t-shirt fits across the chest, it's too snug at the hips.  If it fits at the hips, it's too loose at the chest and shoulders.

Cut the t-shirt to curve up, above the hips, on the sides.  Shorten the front and leave the back long, so it stays tucked in.

DD inherited the same build so you see mommy and me black t-shirts trimmed and ready for hemming.  I serge finish the bottoms, turn up, hem with a twin-needle, and give the hem a good press.  30 minutes and we both have basic black layering Ts.

As I wrote in Embedded water: cotton, a cotton t-shirt contains 700-1000 gallons of embedded water and ~1 pound of pesticides.  Let's get maximum utility out of that water and reduce our global pesticide use.

Thursday, September 17, 2015

Black watch tiered skirt #7

#1 Blue
#2, 3, 4 Hello Goth! 3 Gray tiered skirts
#5 Household sewing pink and gray tiered skirt
#6 Blue again

Is it a command performance if she isn't royalty?  How about a demand performance?

Anyway, I started with Bad Dad's badly frayed black watch plaid shirt.  Over the years, it had deteriorated from a lightweight canvas to a poplin-like weight and softness.
Auditioning fabrics.
While I was auditioning fabrics, I came across this 1/4 yard scrap of Jinny Beyer quilting cotton.  The last time I bought Jinny Beyer fabric, I was in grad school.  My JB purveyor back then was Elfriede's Fine Fabrics.

I bought this fabric nearly 20 years ago for a green + purple tessellated quilt that now lives with my SIL.  I saved the scrap, moved it to LA, and then moved it back to Boulder--only 1 block from the store where I originally purchased it.  The scrap, in the form of a finished skirt, is going back to LA.

Well-traveled fabric.
Enough about the fabric.  You want to see the finished skirt.  Notice that I swapped out the midnight navy pin dots for a solid black poplin.
Each side has a flash of white.
Another view from a different side.
Spread out on the floor.
I used a pleating foot, set to pleat every 6th stitch.  I made a test sample and got a 1.67 ratio of unpleated to pleated length using a scrap of the swirly quilting cotton.  That was a bit more than I wanted so I increased the stitch length from 2.7 to 2.8 mm.  Mistake.

Machine pleaters work best on fabrics with 'grip' such as quilting cotton.  They pleat much less effectively on slippery fabric such as the fine cotton poplin at the top.

I start with a 9" deep top tier cut at 120-125% of the hip width of the wearer.  The other 3 tiers are 8" deep.  After making the waist casing, I end up with 4 tiers about 7" deep.

Warning:  At a 1.67 ratio, that means a finished hem of ~200".

The recycled shirt fabric will wear out fastest, so arrange those on the bottom.  When they rip, it won't be a major embarrassment.  ;-)

Cut the shirt bottom 9" deep at the center fronts.  The sides curve up so your overall skirt length will be 29-31".  Reuse shirt hems to reduce the amount of hemming you need to do.  Hem the fabric strips attached to the shirt hems before joining them!

If the selvedges are an even tension, leave them in place.  You can use their non-fraying edges and the shirt placket to encase the raw edges of other pieces for a clean finish.
Reuse hem and plackets.
Clean finish in two steps:

  1. Sew the RS of the raw edge to the WS of the clean edge, with the clean edge extending about .5".
  2. Flip the raw edged piece so the RS is behind the clean edged piece and topstitch from the RS.

Pocket flap button resewn after assembly.
Cut the buttons off before assembly because they get in the way.  After assembly, I sewed the button for the pocket flap back on.
Interior view of pocket.
I think inclusion of the pocket is a fun detail.  When you leave pockets on, make sure they land at the unpleated bottom edge or else it will get too bulky.  Set the pleater to 0 when you cross seams and shirt plackets.  You don't need to add pleats and bulk at these places.
Clean-finished interior with one serged vertical seam.
I like the way the selvedge gives a flash of white.
Use selvedges, too.
I bought two t-shirts at Goodwill that perfectly match the skirt.  I plan to make a mock-wrap shirt to complete the outfit.
One of two thrifted shirts perfectly color-matched for top.
DD says that the wabi-sabi rips and frays are an integral part of the design of these skirts.  As they rip, I will layer other fabrics and patch it up as I did here.

This skirt too 5 hours of work time spread over 6 hours of elapsed time.  That's 300 minutes of work for a skirt that is already frayed and will continue to degrade.  This isn't clothing construction; this is performance art.

I've been following Handmade by Carolyn's One year, one outfit project.  She's making an outfit entirely made up of components sourced in her local environment of Western Australia.  That is not easy in this day of globalization.  Zippers and buttons are made in only a few places in the world now.  She's making everything from scratch--right down to carving her own shoe soles from local wood.  I am in awe of everything she does.

My particular performance art shtick* is to see what I can make from castoffs.  Bad dad wore the shirt for years until the visible fraying wasn't fit for public wear.  The small sprigged print is leftover from a quilt project.

The other two fabrics come from odd-jobbers in LA.  The black poplin appears to be a fabric sample used in a wash/shrinkage test and the swirly black/green quilting cotton has small printing flaws.  To most people, the components are textile waste.  To DD, this is her signature look.  To me, this is how I assuage my enviroguilt for living in two places** and flying back and forth.

* Carolyn, I don't mean to call your project shtick.  I'm only saying that my work is shtick.

** To be fair, two-PhD families have a very rough time finding jobs in the same place so this living arrangement isn't something we have control over.  That doesn't make the enviroguilt completely disappear.

Wednesday, September 16, 2015

Tuesday, September 15, 2015

30 minute skirt

Please excuse this blurry picture of two black skirts. You've seen one ponte pull-on skirt, you've seen them all.
Destined to stay in the closet. Vogue 1224 on the left, Simplicity 1072 on the right.
When DD asked for more skirts, specifically more tiered ruffled skirts made from recycled shirts, I blanched. Those are extremely time-consuming compared to simple pull-on skirts. Last year, I made her two tops, two skirts, a pair of shorts and a nightgown. The swirly green skirt gets tons of wear. The black pencil skirt, just once. The scuba knit top got worn none at all.

When she asked for more skirts. Emphasis on the plural. I talked her into one time-consuming one and one quick one. I saw this black ponte and Simplicity 1072 on top of my pile of supplies. The serger was already threaded up in black and the cutting supplies were set up. I whacked this out in 30 minutes. I even improved the fit with back waist darts.

Note to self, she doesn't need a black pencil skirt.  She already has one and never wears it.  She says that they are too confining.

Actually, my slim skirts get very little wear for the same reason*.


Will I ever learn?

These skirts were quick, but a complete waste of my time.  Next, the 300 minute skirt she wanted.

* A physical therapist says that skirts that force you to sit with your knees pressed together will cause your hips and lower back to ache.  Your knees naturally want to splay out a bit and you should not confine them in one uncomfortable position all day.  Who knew that narrow skirts are the sartorial equivalent of high heels?  (I mean that in the sense that PTs treat many women injured by them.)

Monday, September 14, 2015

The importance of narrative

I love a good mystery. I think that is what first attracted me to quantum mechanics. The way my professors taught it (and the textbooks were structured), quantum theory unfolds like a great detective story.  Pieces of evidence rolled in, players moved about, the truth gradually emerges.

The narrative is so strong, you can put together a timeline of the discovery of quantum theory.

Has anyone done the same for the weather?  If you know of one, can you leave it in the comments?

I had hoped that Weather Experiment would be that book, but it isn't.  It's not even "The pioneers who sought to see the future" as the subtitle claims.  I agree with this review in the NYT; the book is about british men and (mostly) ignores the work in other places.

American James Espy and Frenchman Urbain Le Verrier get brief mentions, but this is mostly a bunch of stories/biographies about british men strung together.

If you are looking for a coherent narrative of scientific discovery, look very, very carefully.  There are nuggets tucked in here and there.  When narrating who argued that air masses move up and who argued that they moved in circles and who said that they move horizontally, some context would have been useful.  It is possible that they were all right, given their life (weather) experience.

The book is fine if you are expecting a bunch of human stories about people who are affiliated with the study of weather as it was practiced in England.  There is a useful index.  Also, "Stars in FitzRoy's Meteorological Galaxy" just before the index, gives a synopsis of the players, including the ones given short shrift or omitted in this book.

It hadn't occurred to me before reading this book that predicting the future is a form of divining the future, and had caused religious crises of faith.  I also learned that accusations of data-hoarding are not new.  ;-)