What's scaring people about AI

The thing that is scaring people about AI — the hot issue in AI ethics right now — is not the humanlike behavior of the software.

It is that people are putting unreliable software in charge of things that can harm human beings.

Until now, we've used computers because of their extreme reliabilty (within limits). That's why you'd rather have your bank account calculations done by a computer than by clerks with pencils.

Machine learning produces approximate outputs, and generative AI produces, at best, educated guesses. Everybody is going to have to start thinking about imperfect reliabilty and how to measure it.

And get used to using generative AI for rough estimates and suggestions, not final answers!

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Turtle

Today I wanted to get my two Nikon CoolScan slide scanners working. (They have to be used occasionally to keep the lubrication on their mechanisms from getting too sticky.) To try them out, I opened a slide album and picked a slide — a picture of our pet turtle in the mid-1990s. Enjoy!

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Current on the ground wire

While reviewing our planned electrical work, I came across something else that is seldom explained well, and even electricians (or at least handymen) sometimes misunderstand it. It's why the neutral wire is tied to ground in only one place.

Here is how electricity normally enters a house. I've left out the circuit breakers, and I've shown half of the transformer unconnected; normally, half of the 120-volt circuits use one side of the transformer, half use the other, and the 240-volt circuits use both.

The live and neutral wires deliver power. The ground wire is only protective; its purpose is to make sure that the metal cases of appliances, metal outlet boxes, metal pipes carrying wires, etc., can't shock you.

The ground wire goes to a metal rod driven into the ground. It is tied to the neutral wire at only one place, normally the "first point of disconnect" where your main switch or main circuit breaker is. (In our older house, it's in the breaker panel, but it will be moved to be outdoors, near the meter.)

Ground and neutral are tied together to ensure that the neutral wire is never at a very high voltage, and that live and neutral cannot, together, be elevated to some dangerously high voltage through an accidental connection to something else.

Here is how current normally flows. Every electron that comes out the live wire goes back to the transformer through the neutral wire (or the opposite, on the opposite half-cycles of the alternating current).

Live and neutral deliver the power that does the work; ground is a protective connection to the case or housing of whatever you're powering. Small, low-power devices such as radios often don't use a ground connection; they have a two-prong plug that may or may not distinguish live from neutral. More about that here.

So what happens if neutral and ground get tied together again downstream? Knowing they are tied together at the entrance, some people mistakenly tie them together again somewhere else, in an outlet box or inside an appliance. Then this is what happens:

Now the ground and neutral wires share current, and oops! The ground wire is carrying a heavy current, which it wasn't designed to. If this happened downstream from a GFCI, the GFCI would trip, but if it were in an outlet box, that probably wouldn't happen.

Here is a particularly good demonstration that makes it clear what happens. In that demonstration, the voltage difference from neutral to ground was probably only about 5 volts, not enough to shock anybody, but the available current was 22 amps, about a third of which ended up flowing through the ground wire. (And probably heating up the alligator-clip lead that the man was using to demonstrate the accidental connection!)

About putting the main breaker outdoors, with the meter: This newer practice makes it possible for firefighters, or anyone discovering a fire, to cut electricity to the whole house from outside it. That can be lifesaving. The way our house is built right now, if it caught fire, we'd evacuate the bedrooms first, and then be unable to get to the main breaker, which is in a bathroom closet!

It also ensures that there is no wiring in the house not protected by a circuit breaker. Right now, if there were a short in the main cable from the transformer, that could easily be inside the house, upstream from the main breaker, and we wouldn't have any protection from it.

Why do I write things like this, when nobody is paying me? Well, why does a violinist play the violin when not preparing for a concert? I write partly to stay in practice, and partly because I enjoy finding good ways to explain things. Expository writing is in my blood.

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Calculus puns

(Out of mercy I will not name the people who helped me continue this series of plays on words; the first one is my own; it all happened on Facebook.)

Among many other controversial claims, Karl Marx argued that calculus is ill-founded because derivatives involve dividing by zero.

Hearing this, I remarked, "See? Marxism knows no limits."

One replied: "The Eagles sang, 'Take it to the limit one more time.'"

I said: "That's a second derivative pun."

Another replied: "The puns are accelerating."

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Circuit breakers, AFCIs, GFCIs

We are about to get some major electrical work done on our house, including the addition of a large number of AFCIs. (I have been adding GFCIs piecemeal for years.) In looking at people's conversations and videos, I see a lot of things being misunderstood, so, in order to have something to point people to, I'm going to try to make a few things clear.

Basic electricity: Complete beginners may not realize that electricity does not flow out of an outlet the way water flows out of a faucet. Every electron that comes out one of the slots in the outlet (live or neutral) goes back into the other slot. Along the way, it passes through something such as a light bulb, where it gives up some energy and gets some work done, such as lighting the light.

Think of electricity as like a saw — doing work by being dragged across or through something — rather than like a fuel that is fed into something and consumed there.

In fact, a saw is a particularly good example because we use alternating current — it switches direction 120 times a second (taking 1/60 second to go through the full cycle; that is what we mean by 60 Hz). (50 Hz in Europe.) Saws work that way too, switching direction as they go back and forth, and doing work on both strokes if suitably designed (which is more important for electricity than for handsaws).

Protective devices: Now to what I was going to write about...

Circuit breakers are located in the breaker panel (fusebox). They protect against:

• Overloading, too much current being drawn through a circuit, such as when you plug several space heaters or vacuum cleaners into outlets that are fed by the same wires.
• Short circuits where the live and neutral wires are touching, either inside an outlet box, inside a cable, or inside an appliance; or when the live wire is touching the ground wire. Circuit breakers trip only if the short circuit is a good, consistent unwanted connection and lasts at least half a second or so.
• Both of these things are fire hazards.

Note: "Short circuit" does not mean "loose connection." It means electricity is flowing freely from the live wire to the neutral or ground wire without doing any work (except heating up those wires and eventually starting a fire). Of course, a short circuit can be caused by a wire coming loose and solidly touching another wire.

AFCIs (arc-fault circuit interrupters) are a relatively new invention and are usually combined with the circuit breakers. They protect against:

• Loose short circuits where wires are touching lightly, causing intermittent sparks (arcs).
• Loose connections, breaks in a wire or connection where contact is still being made some of the time, causing sparks as contact is made and then lets go.
• Both of these are also fire hazards.

AFCIs detect sparks by the way they start, stop, and resume very suddenly, causing current to start and stop on a microsecond timescale. That is true whether the sparking is caused by a loose short circuit or just a break in a wire that is carrying current. Some old types of electric motors normally have sparking inside and can trip an AFCI.

GFCIs (ground-fault circuit interrupters) are usually built into outlets, and can protect additional outlets that are wired through them, but they can also be built into circuit breakers. They protect against:

• Mismatch between current flowing out and coming back, indicating that some electricity is escaping into something outside of the wiring, or possibly into the ground wire.
• That is often a situation where a human being would receive an electric shock, such as by touching a live wire while standing on the ground, or dropping an electric hair dryer in the bath water.
• Because the house electric system is grounded, escaping electricity makes its way to the ground (the earth) through soil, water, water pipes, or the grounded outer frame of an electric appliance. That's why this situation is called a ground fault.
• GFCIs protect against electric shocks, not fires.

Some people think the GFCI detects current flowing into the ground wire. It does not; in fact it does not even need a ground wire. The GFCI detects a current imbalance between live and neutral.

Most importantly, none of these protects against all electric shocks, nor against all possible electrical fires. Circuit breakers protect against the worst short circuits. AFCIs protect against many more short circuits, since short circuits almost always arise gradually and start out loose, and also protect against loose connections that are not shorts. GFCIs reduce the risk of electric shock in situations where water or damp ground are involved.

But if you touch both the live wire and the neutral wire, you will get a possibly fatal shock; the wires won't know you're not an electrical appliance.

Likewise, you can still use power from the wires to overheat something and start a fire, though with AFCIs, you could only do it with something that consumes current as steadily as legitimate heaters, lights, and the like; a loose or worn-out wire is not likely to do it.

I have come to feel that AFCIs are the more important of the two, but both AFCIs and GFCIs are needed. Why shouldn't we be as safe as we can be?

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An hour in the 20th Century

Yesterday (December 31) I spent an hour in the 20th Century, or so it seemed. I went to the post office to mail a letter and actually went up to the counter to make sure there was enough postage on it. Then I went to Kroger, and after picking up a prescription, bought a newspaper.

Two things that were unlike the 20th Century were the extremely smooth-running engine of my car (much smoother than anything not microprocessor-controlled) and the fact that at no point did I smell cigarette smoke, which used to be the unavoidable smell of public places in America.

The newspaper was, in fact, the very final print edition of the Atlanta Journal-Constitution (AJC), the newspaper all Georgians grew up with. Melody missed an opportunity to work for this newspaper when I plucked her out of Atlanta to get married and move to Los Angeles in 1982. She was then working for the newspaper in Marietta.

When we were children, the Journal and the Constitution were separate newspapers, combined only on Sundays. The morning paper, the Constitution, was printed in the dead of night and trucked all over Georgia so that it was, in fact, our morning paper even in Valdosta, and we got the local Valdosta Daily Times in the afternoon.

The AJC continues, of course, as a web site for subscribers.

It has been more than 20 years since we had newspapers delivered to our house. The Internet has supplanted them, but imperfectly. The problem is pricing. Much Internet news is free, totally ad-supported. Major newspapers, however, still require subscriptions, which few people feel the need to pay for (we don't). We're aware that we get appreciably less local news than we used to. This effect may in fact be tearing apart the fabric of towns, turning small cities into mere suburbs with less of a local identity.

I wish they could make themselves fully ad-supported. The key to it may have to do with how you see the ads. In a print newspaper, the ads are something you look through — almost like a city directory — particularly the classifieds. On the Internet, as on TV, ads are things that intrude into what you are doing. Is there a way to turn them into something interested shoppers will actually browse through, the way they did newspaper ads?

I don't know how much the AJC was selling for normally, but the price of the final issue did strike me as a bit daunting. Eight dollars can pay for a lot of Internet access.

It was a poignant moment when I sat down to read the day's Atlanta newspaper for the last time. I had not done so in years, but it's something I did almost every day for decades.

I didn't read everything of course; just as in the old days, I looked at maybe a quarter of what was there. But there were entertainment items that I would always look at because they were there, even though I didn't seek them out on the Internet: the comics (in color in this issue), the Jumble (a word puzzle), and Dear Abby, whose first question this time was about a chatbot.

Other printed newspapers still exist, but this old familiar one is gone.

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Who is this "Penny Rounding"?

In keeping with the spirit of the 20th Century, I paid for the newspaper in cash, and to my surprise there was a new line item on the receipt, "penny rounding." Kroger gave me a 4-cent credit in order not to have to give me pennies, which are being discontinued by the Mint.

It appears that Kroger always rounds in the customer's favor. The other way to do it is to always round to the nearest multiple of 5 (thus 1 and 2 round to 0, but 3 and 4 round to 5; my price of $8.64 would have rounded to $8.65).

I've already seen people on Facebook saying, "This rounding always makes you pay more, it's another sneaky trick." No, it doesn't. Someone shouldn't have slept through elementary-school arithmetic. Rounding to the nearest multiple of 5 should be fair, assuming the price before rounding can be anything. Of course, if a merchant were to arrange for the prices after tax to always end in 3 or 4, they'd gain a few cents, but it would take a lot of effort.

There's a simple way to eliminate the problem. Round the amount of sales tax to the nearest 5 cents.

No, I didn't say change the tax rate, which is what people usually think I mean when I say that. The tax can remain 8%, as it is now. The tax on $10 will remain 80 cents. But the tax on $1 would not be 8 cents; it would round up to 10. Likewise, the tax on $1.50 would not be 12 cents; it would round down to 10.

If the amount of sales tax were always a multiple of 5 cents, and the merchant's prices were always a multiple of 5 cents, no further rounding would be needed. The merchant would not be taking a loss or a gain — just collecting the amount of tax prescribed by law. Numbers that are not multiples of 5 cents would disappear from our economy.

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