Thursday, March 22, 2018

Wednesday, March 21, 2018

Facebook and Cambridge Analytica

Why all the fuss about Facebook data being mined by a third party for political purposes? Facebook has been selling personal data to advertisers (and I think to anyone else that paid the price) from the very beginning. Its business is collecting and selling data about you. That’s the service for which they get paid. You don’t pay them to provide the means of keeping in touch with your friends.

So why the shock when it’s revealed that some people want to sell you political beliefs instead of shoes? When it comes to “free” media like TV and Facebook, you are the product.

I think the only surprise is that someone had a pang of conscience and revealed Cambridge Analytica’s shenanigans. You can be quite sure that Facebook data is being mined by anyone that wants to do so. Heck, you can do it yourself on your own machine. Just snip and save whatever you want, and look it over at your leisure. I’m pretty sure there are programs out there that will do this for you automatically. Look for “archiving software”.

Facebook was designed to be easy and convenient to use, and that is what makes it open to anyone who wants to mine data. It links files together so that many people can, if they wish, read the same file: A note about your meal, a picture, a link to a website, a video, whatever. And each of these items is labelled with your name. It has to be. Else it couldn’t be seen by you on your Facebook page.

But that means that Facebook has that labelled stuff on its servers. If there’s enough labelled stuff about you, it’s easy to figure out what kind of person you are. That’s what makes that data valuable for advertisers. It’s how Facebook figures out what ads to show you. It’s how Amazon decides to show you what “People who bought this also bought...” Etc. IOW, Facebook etc merely do what we all do: A “person we know" is really the collection of everything we know about them, plus what we think it all means.

What isn’t clear is how Cambridge Analytica got hold of all that data. There’s a good deal of fudging around this question. Facebook CEO Mark Zuckerberg has said almost nothing. It seems CA hacked into Facebook’s servers to get the data,. That’s bad. But if Facebook sold them the data, I think that’s worse.

Sunday, March 18, 2018

How efficient is a car?

The Second Law of Thermodynamics puts an upper limit on the efficiency of a heat engine. The most efficient heat engine is a Carnot cycle engine, named after Sadi Carnot, who worked out the  maximum theoretical efficiency of any heat engine. It’s (1- Tc/Th), where Tc is the temperature of the cold side of the engine, and Th is the temperature of the hot side. Heat flows from the hot to the cold side, and on the way some of it can do useful work.

So how much work can a gasoline engine do?

In real life, friction and other factors reduce the efficiency of the engine. Long years of experience with gasoline engines shows that typically they operate at about 25% efficiency. That is, of every 100 litres of fuel you put in your tank, about 25 litres move the car and what’s in it. The other 75 litres are wasted in the form of exhaust gases, friction, heating the engine, etc.

That’s the efficiency of the engine. It’s not the efficiency of the car.

To calculate the efficiency of the car we need to know the total weight of “the car and what’s in it”. You, the driver, are in it.

Let’s say you are a typical Canadian male and weigh about 200 lbs (90kg). A car itself typically weighs about a ton (2000 lbs, or 900kg). Together, you and the car weigh about 2200 lbs, or 1 tonne (1,000kg). So you weigh about 10% of the total.

So only about 10% of those 25 litres that move the car and you actually move you. Or, thinking about the fuel in the tank, out of 100 litres, 2.5 litres are used to move you down the highway.

That means the overall efficiency of the car as a means of transporting its lone driver is 2.5%.
Since fuel costs money, that means of every $10 you spend, 25 cents will pay for your transportation, and the other $9.75 pay for moving the car, wearing down its parts, and heating the air.

You can increase that efficiency. A lighter car is more efficient, because you make up a larger fraction of the total weight. A car loaded with passengers and their gear is also more efficient, for the same reason. A vehicle that carries a lot of passengers and a lot of gear, like a van or a bus, will be even more efficient. However, with just the driver, a van or bus will be less efficient. A pickup truck, which weighs considerably more than a car, will always be less efficient.

From a selfish point of view, one should buy the lightest car one can use, and use it as little as possible. From a social point of view, one should probably not use a car at all, or only when absolutely necessary.

Friday, March 16, 2018

Richard Stein, architect: Energy Conservation n the Building Trades.

Richard Stein was Ethel Stein husband. His obituary includes some interesting calculations about the efficiency of buildings.

Textile Artist Ethel Stein (link to obituary)

Textile as an art medium is of course underrated and often dismissed as mere craft. Ethel Stein is one of many people who have been overlooked for this reason. Which means that I knew nothing about her until I read her obituary. I suppose some would say that's a minor deprivation, but I disagree.

Monday, March 12, 2018

So You Want to Build A Model Railroad... (Mid-sized Trackplan)

      Ian Rice. Mid-sized and Manageable Track Plans. (2003) Rice doesn’t design track plans. He designs layouts. The difference is that a layout has a theme, usually based on a prototype and one or more of its locations. While layouts rarely copy the prototype exactly, a good design will use the tricks of selective compression, key structures, and characteristic landscapes to create a believable impression of a real railroad.
     It’s not much of a trick to arrange track to fit a given space. Many model railroaders do that with actual pieces of track placed on the table or benchwork, which has also been built to fit the space. But whether the trackplan is drawn or sketched on paper or a computer screen, or laid out with actual track, the challenge is to translate the trackplan into a layout. Rice has the gift of visualising the end result, so he includes buildings, scenic elements, and often view blocks to encourage the visitor to see only one scene at a time. His layouts tend to be a string of dioramas.
     Rice also selects a time frame, and describes the locomotives, the traffic, and other components that will fit that time frame. He fits the benchwork to the trackplan, not the other way round. His layouts feature not only sweeping curves of track but sweeping curves of benchwork.
     The layouts shown here fit four standard sizes: a 12ft x12ft bedroom; a 10ft x 16ft corner of a basement; a 10ft x 20ft single garage; and a 20ft x 20ft double garage. Almost all use a 24 inch or larger minimum radius. They are certainly manageable, in time, money, and space. Rice discusses these and other constraints and determiners of model railroad building in the first three chapters, then offers fourteen plans, with accompanying discussion.
     He’s a good writer, if somewhat too fond self-deprecating lame jokes. Anyone who’s starting out in the hobby will find this book useful and inspirational. The model railroader who’s become dissatisfied with what’s been built, and is willing to tear down and modify or even start over, will find this book a good source of ideas to guide the redesign. Recommended. ***½

Wednesday, March 07, 2018

A wheelbarrow of cash for a loaf of bread: The Downfall of Money (F Taylor)

     Frederick Taylor. The Downfall of Money (2013) The story of the German hyper-inflation that followed World War I, 1919-1923. Taylor mixes political, economic, and personal stories, which gave me a vivid impression of what it was like to live through that time. For example, a memory of how the family would get the father’s salary at the beginning of the month, and strive to spend it all on food and other necessities by noon or early afternoon at the latest, before the prices went up. With luck, the haul lasted until the first of the next month, when the exercise was repeated.
     Taylor is also good on thumbnail sketches of the politicians and their motives. He emphasises the murderous mutual vilification of left and right, which came near to outright civil war. We can see the beginnings of the tangled path of cross-purposes, and more or less blatant betrayals, that led from the Weimar Republic’s inability to forge a national unity to the handing over of power to Adolf Hitler.
     The book is highly readable. Taylor has done his homework: the list of sources occupies six pages of small print. He has the knack of synthesising huge amounts of information, clarifying the narrative lines, and dropping telling details at the right places to create the personal, human scale that allows us to form an impression of reality.
     As a believable story of the times, the book is very good, As an analysis of why and how the awful events unfolded, it is weak. It’s clear enough that French intransigent refusal to renegotiate reparations payments played a key role, as did American insistence on repayment of debts. It’s also clear that the German inflation was in part deliberately induced to reduce the accounting value of the reparations. A side effect was that all that excess money created consumer demand, so for a while there was a boom. But since the money supply grew faster than production, that did not last.
     In addition, the government was unwilling to risk the effects of a limited money supply, which would have stabilised the currency, but which would also have required siphoning large amounts of cash out of the economy in order to pay reparations. The last phase, hyper-inflation, created grievous hardship.
     In short, Taylor is good at presenting the immediate causes of the inflation. He does not raise the question of underlying causes. Inflation is a puzzle: Why do people come to expect to hand over more and more cash for the same quantity of goods? And why do central banks supply that cash? Why do people believe that austerity (borne mostly by other people, of course) will generate a desired surplus of cash for payment of debts?
     The German hyperinflation is a good case study in the role of psychology in the economy. People make decisions (such as investing in war bonds) because of their beliefs about how the economy works. When those beliefs prove unreliable guides, they act on different beliefs (and spend a month’s salary in half a day to get enough food to last the month). To understand inflation we need to understand what people believe about money.
     It’s pretty clear that the dominant belief operating in the postwar period was that money is wealth. That’s why the French wanted money from the Germans. That’s why the Americans wanted the Allies to repay the money they borrowed. The French did insist that at least part of the reparations should be paid in kind (iron and coal, mostly). But what they wanted was gold marks, actual bullion, or paper money that was guaranteed to be exchangeable for gold. Neither the Americans nor the French were willing to forgive the debt owed them, nor to help Germany rebuild its economy so that they could supply the goods and services that France and Belgium needed for rebuilding. It was all about the cash. I think it not at all surprising that the German government decided to provide the cash, in the end by the wheelbarrow.
     Could inflation have been avoided? I don’t think so: devaluing currency is a handy way to reduce debt, and everybody did it to some extent (the British and Americans least of all, which is why the pound held its value against the dollar). But once people realised that cash is not wealth, and preferred things (food, clothing, furniture, jewellery, etc) over cash, hyperinflation was the predictable result. Then if inflation becomes bad enough, people are willing to swallow the bitter medicine of currency reform, and the sharp but relatively short-lived pain of adjustment to the new bookkeeping.
     Money works only as long as people trust it. Whether “backed” by gold or not, money is a measure of value, just as a meter stick is a measure of length. There’s a difference, though. The value of a dollar depends on what people believe it to be. A $10 bill is an IOU: as long as we trust it as a “medium of exchange”, it can be cashed in for real wealth: a meal, a book, a few gallons of gas, a pair of gloves, a theatre ticket, a sack of potatoes.
     Good book, worth reading as history, and as an object of meditation about the nature of money. ***