It's About Time, Part II

Super clocks: More accurate than time itself

An article discussing the progression of atomic clock technology, and also relating to something I posted earlier, a discussion of what happens when the next generation of atomic clocks is deployed: the clocks won’t be the limiting factor in determining the time.

To tell the time consistently, all clocks need to be at a known height relative to Earth’s “geoid”, an imaginary surface that links points at which the gravitational field has the same strength. But the height of this geoid varies over time at any given place by up to 20 centimetres, because of effects such as tectonic movements, glacial melting and changes in ocean levels, and varying atmospheric pressure. Changes of that magnitude could wreak havoc with any attempt to establish a global time standard at an accuracy of 1 part in 1018 or better

One of the things that always glossed over in these discussions is that almost everything that is called a clock is actually a frequency standard, which is part of a clock. Clocks run continuously, because you are measuring a phase, and frequency standards don’t. Now, there’s a caveat here in “running continuously,” because even commercially-available clocks will skip measurement cycles to do self-diagnostics. During those skips in measurement, as with the time between measurements, the frequency is maintained with some oscillator. Usually this is a quartz crystal, which typically has excellent short-term stability. The important point becomes how long the clock is running on the “flywheel” oscillator and what kind of degradation that introduces. The latest generation of frequency standards run for several hours, but then are shut down for extended periods of time, which is not surprising for a cutting-edge kind of experiment. But while the frequency standard is not running, the clock’s performance approaches whatever the flywheel performance is, whether that’s cesium beam clocks or hydrogen masers, etc., or some ensemble made up of several clocks.

So when these stories appear touting the great performance of cutting-edge clocks, there’s an unwritten implication that we will be getting an improvement in the flywheel operation as well, to be able to leverage this improved frequency-standard performance.

It was the Blurst of Times

I’m not surprised that there was a controversy over that cartoon which appeared in the Post (one link, in case you haven’t seen it). Al Sharpton, among others, has claimed racism, saying that the cartoon is “troubling at best, given the historic racist attacks of African-Americans as being synonymous with monkeys.”

But what we have here is a failure of logic, combined with human bias. That some depictions using monkeys are racist does not mean that any depiction of a monkey is. Political cartoonists have a habit of using caricature, or when they don’t, of labeling the targets of their satire, neither of which happened in this case. The problem with this medium is that it’s subjective, and interpretations made by individuals reveal their preconceptions and biases — if we look too hard, we see things that aren’t there. I’ve seen it in my own cartoons, when people told me how clever/stupid/offensive I was for including some imagery, which was a surprise, since that’s not what the intent was. After that happened a few times, I realized that I wasn’t going to be held responsible for how someone (mis)interprets a cartoon. It’s rare that something can’t be misconstrued. Al Sharpton is an activist/protagonist. Of course he’s going to see racism.

Here’s another example — and you shouldn’t go below the fold if you aren’t willing to risk being offended.
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If Even a Mouse-Click is Too Loud This Morning, Read This

Under the broad heading of What causes hangovers? which is addressed in the link, along with some other alcohol-related information.

Congeners

Congeners are toxic chemicals that are formed during fermentation, some liquors have more of them than others. These congeners are widely responsible for headaches.

Word to the wise: if you can’t pronounce “congener” anymore, stop drinking.

(h/t to YT and John)

(remember: Beer is good)

Security and Usability

Balancing Security and Usability in Authentication

In most cases, how an authentication system works when a legitimate user tries to log on is much more important than how it works when an impostor tries to log on. No security system is perfect, and there is some level of fraud associated with any of these authentication methods. But the instances of fraud are rare compared to the number of times someone tries to log on legitimately. If a given authentication system let the bad guys in one in a hundred times, a bank could decide to live with the problem—or try to solve it in some other way. But if the same authentication system prevented legitimate customers from logging on even one in a thousand times, the number of complaints would be enormous and the system wouldn’t survive one week.

Balancing security and usability is hard, and many organizations get it wrong. But it’s also evolving; organizations needing to tighten their security continue to push more involved authentication methods, and more savvy Internet users are willing to accept them. And certainly IT administrators need to be leading that evolutionary change.

In my experience, systems that have a captive audience, rather than a voluntary one (e.g. employee vs customer) are much less likely to care about usability in security but also in general, since they can go Nike on you and say, “Just do it.”

related:

Humans are incapable of securely storing high-quality cryptographic keys, and they have unacceptable speed and accuracy when performing cryptographic operations. (They are also large, expensive to maintain, difficult to manage, and they pollute the environment. It is astonishing that these devices continue to be manufactured and deployed. But they are sufficiently pervasive that we must design our protocols around their limitations.)

— Kaufman, Perlman, and Speciner

Stress Test

Lessons In Survival

Getting soldiers acclimated to stress, and weeding out those who can’t handle the truth it.

During mock interrogations, the prisoners’ heart rates skyrocket to more than 170 beats per minute for more than half an hour, even though they aren’t engaging in any physical activity. Meanwhile, their bodies pump more stress hormones than the amounts actually measured in aviators landing on aircraft carriers, troops awaiting ambushes in Vietnam, skydivers taking the plunge or patients awaiting major surgery. The levels of stress hormones are sufficient to turn off the immune system and to produce a catabolic state, in which the body begins to break down and feed on itself. The average weight loss in three days is 22 pounds.

Listen Up!

What is a phonon?

A phonon is a quantized sound wave – a collective vibrational mode of a solid (or liquid). In a crystalline solid, the idea is that the atoms in the solid are displaced, at any given instant, from their equilibrium positions. For a single phonon, the instantaneous displacements are periodic in space (that is, there is some wavelength, where atoms separated by an integer number of wavelengths are displaced the same amount). The displaced atoms feel restoring forces due to their interactions with neighbors, and will tend to oscillate in time around their equilibrium positions.

There’s more, though.

Also see What is a plasmon?