August 9, 2013

Hushmail - Lavabit - Where does the madness end?

Lavabit abruptly shut down today because its owner, in his own words, refused "to become complicit in crimes against the American people." What he means by that we will perhaps never know, due to the accompanying gag order.

But I can't help speculating. My best guess is that the government tried to get Lavabit to do what Hushmail has implied is within the bounds of what a government can do: compel a company to abuse the trust placed in them by distributing compromised software with a government backdoor.

But if a government can do that, then where does the madness end?

Can Apple be compelled to send a compromised version of iOS to a particular iPhone, e.g. keeping the microphone and camera on at all times, sending data to the NSA? Can Google be compelled to do the same for Glass? For a single "target", or even for larger group of "foreign nationals"?

Can Cisco, Juniper and Alcatel-Lucent be compelled to implement functionality in their equipment to siphon off certain network traffic around the word, for the NSA to study in Fort Meade? That would likely make criminals of these companies' employees, at least in other jurisdictions than the US. As unlikely as that sounds Microsoft has already made statements indicating that they (and any other US based company) can be compelled by the US government to hand over personal data stored in EU data centers. That would probably be a crime in most EU countries; e.g. in Sweden it would likely fall under "unlawful intelligence gathering" and a carry prison sentence of up to 4 years.

So where does the madness end? Perhaps nowhere. Perhaps that's why the US government is so afraid of Huawei and ZTE; they know what they themselves are prepared to compel a US company to do, so cannot imagine that Huawei or ZTE could ever say no to the Chinese.

Using force to coerce otherwise law-abiding citizens to commit crimes, that used to be the hallmark of mafia. Has it now become a cornerstone of civil service? We need the UN to step in or something. We need some sort of international treaty.

July 28, 2013

Hyperloop lets you travel on a resonant acoustic wave

Elon Musk is a fascinating guy, and his Hyperloop concept equally so. Now that the details have started trickling out, almost in the form of a riddle, I can't help speculating on what it is.

So, in riddle form:
It takes you from LA to SF in 30 minutes,
it leaves when you arrive,
it can store energy over many hours or even days,
it can't crash,
Elon Musk calls it a "Hyperloop" and
it's not an evacuated tunnel. What is it?

The best speculation I've seen so far is Charles Alexander's. My guess is a variation on the same theme: Elon Musk's Hyperloop is a double tunnel connected in a loop, designed to resonate acoustically at a low frequency with "standing waves" traveling around the loop, each wave capable of carrying a small capsule with goods or passengers at almost the speed of sound.

My knowledge of acoustics is far too rudimentary to go into the physics (or even feasibility) of this design, but my gut tells me that it should be possible to generate standing waves even in a very long pipe or tunnel, and it's well known that acoustic waves can be used to exert a force on an object. The video below shows a beautiful example, albeit on a significantly smaller scale.

As the term 'standing waves' implies these are not ideal for travel. But when you connect the ends of the tunnel into a loop you remove the edge conditions on the wave equation and I would not be surprised if there are then solutions with similar energy preserving characteristics as a standing wave, but where the wave fronts instead travel along the tunnel at just about any speed up to the speed of sound. Imagine the droplets in the video being capsules carrying goods and people, and instead of levitating, being pushed through a tube at almost the speed of sound. That's what I think the Hyperloop is.

Again, I haven't made a single calculation to verify this design is even possible. Instead I will prove my case in prose!

It takes you from LA to SF in 30 minutes

This means you must be traveling at about the speed of sound. Let's say 90% of the speed of sound, pushed along by a traveling resonant wave going around the Hyperloop.

(It could be that there's a pure traveling wave solution to the wave equation with favorable energy preservation characteristics. My gut however arrived at this design by first imagining a standing wave and then slowly phase shifting it up to speed, while fulfilling the wave equation. It therefore tells me something weird could happen as velocity approaches the speed of sound.)

It leaves when you arrive

Clearly, if it's a standing wave then you'll have HZ departures a second to choose from. No waiting at the station. Just crawl into a capsule and be catapulted up to speed before entering the Hyperloop.

It can store energy over many hours or even days

This is what gave it all away. Just kidding, but there aren't that many designs that can store energy for a longish time. Here it would take some time to build up the resonant standing wave and that would in effect be a form of energy store. My gut tells me it's not entirely impossible that you could build up wave energy during the day using solar and use it during the night.

But again, I could be completely off; a combination of gut feeling and prosaic elegance is not certain to lead to revolutionary transportation system design.

It can't crash

Steering of course would be trivial. But also, if there was ever a terror attack or something like that the tunnel would be opened up to the outside atmosphere. That would immediately ruin the resonance and all capsules should come to a screeching halt. This sounds remarkably safe for a "train" traveling at near the speed of sound: if there's any problem with the "rails" up ahead the "cars" would be notified at twice the speed of sound, in order of distance to the break, and will automatically lose power.

Elon Musk calls it a "Hyperloop"

Elon Musk is a smart guy, and super logical. I'm willing to bet he would not call it a "loop" if it wasn't, or if that fact was not important to the functioning of the system. This is one of few designs I can think of where the loop property is essential. You can't have a traveling resonant wave without it.

UPDATE 28/7: After the discussion on Hacker News I'd like to clarify that
  1. the reason it might be better to push capsules along with a sort of acoustic propulsion like this is of course that it may require less energy than overcoming the air resistance with some other method of propulsion, and/or be cheaper to build,
  2. using a "rapidly phase shifting standing wave" would avoid having to travelling at exactly the speed of sound (as in Charles' proposal), which my gut tells me would be beneficial because otherwise you'd likely have supersonic airflow somewhere over the craft and that usually ruins efficiency, and finally
  3. the energy economics of a system like this would of course depend heavily on the rate of energy dispersion along the tunnel, which would depend heavily on the stiffness of the tunnel wall (and therefore difficult to calculate), but my gut tells me that low frequency sound e.g. from blasts of various kinds sometimes travel several times around the earth, and that implies that propagation characteristics could be quite good.
I rest my case.

Vote on Hacker News

March 17, 2013

What's wrong with the Cyprus bailout

The financial blogosphere is ablaze with talk of a bailout in Cyprus. The short story is that Cyprus has been forced by Germany to rob deposit holders of 6.7% - 9.9% of their bank balance, in the form of a so-called 'upfront one-off stability levy'. Not unsurprisingly people are screaming theft, bloody theft.

After some thought I have to say I agree, but with slightly more nuance: There's nothing immoral about imposing losses on deposit holders. Banks fail. People lose money. That in itself doesn't make it theft. Money is not unconditionally safe just because it's on deposit with a major financial institution.

But when loses are imposed in a way that benefit some at the expense of others, then we are approaching that moral boundary. Bankruptcy law typically says that loses are to be imposed in a certain order:
  1. First shareholders are wiped out,
  2. then junior bondholders,
  3. and only then senior bondholders and (uninsured) deposit holders.
In societies as far back as Rome it has been considered a crime to circumvent this order, to benefit junior creditors at the expense of senior.

But in modern day Europe there's also deposit insurance. This is usually a guarantee that deposit holders will receive their first 100 000 € back from the government, if their bank should fail. The government of course has other liabilities, like government bonds, but in my opinion it can at least be argued that deposit insurance should be seen as senior to bonds.

This gives us an idea of the order in which a "morally just" bailout would impose losses in a situation where both the banking system and the government are insolvent:
  1. First bank shareholders should be wiped out(!),
  2. then junior bank bondholders,
  3. then senior bank bondholders and uninsured depositors,
  4. then government bond holders,
  5. and finally, only if the above doesn't cover it, insured deposit holders will have to take a haircut.
We seem to be pretty far from this in the case of Cyprus: Shareholders will likely be diluted (because deposit holders will receive some "compensation" in the form of bank shares) but not wiped out. Junior bondholders on the other hand may be. Uninsured depositors will receive 90 cents on the Euro while senior bondholders will likely be made whole(!), and so will government bondholders. But insured depositors will take a 6.7% hit.

Many say this is still the best option. If loses are imposed on senior debtors or government bondholders there will be "contagion", and if shareholders lose faith the banking sector could implode. Safer then to take a little from the many, hopefully diluting the sense of loss enough to get away with it.

But a crime isn't suddenly okay just because you have a good reason. As painful as the failure of a major financial institution may be I don't think it compares to the pain we all have in front of us if we abandon the rule of law. So, in my book the proposed Cyprus bailout is theft. Yes, even if you call it a tax.

Fiat justitia ruat caelum, "let justice be done though the heavens may fall." That's my 2 cents at least.