een done. S-72 and X-50 prototypes. Its very unstable. The bring a rotor to a controlled stop thing is easy, existing rotor brakes can be geared to align it fairly precisely when it comes to a stop. The lift transition is the issue. It's not just that lift is basically 0. It's that one half of the rotor disc (the theoretical abstract describing the lift forces) has to completely reverse the airflow of the lifting surface.

Its essentially an expanded case of the Retreating Blade Stall problem.

But the retreating half of the rotor disc has to, as some point, go from generating lift from a retreating motion through the air (moving backwards relative to airframe, due to rotation) to generating lift from an advancing motion through the air (moving forwards, relative to airframem though no longer rotating). The easiest way to think about it isnt to think of it as going from rotating to fixed, but rather think about a rotor that is simply being reversed in direction (simplfies a lot of math).

So at some point in the middle there, half the rotor disc will fall below stall speed, and experience a stall similar to the effect of a Retreating Blade Stall. Worse, won't regain sufficient lift until its now going ~100 KIAS in the opposite direction. Think of it as stalling between -100 and +100 KIAS (example number) as it crosses the transition.

The only craft I can see being able to cross that boundary zone would be a very small, very lightweight rotor that is able to make extremely fast accelerations, and thus cross the zone before it's able to affect the craft much. A full scale craft would simply have too much inertia/momentum to be able to make the transition fast enough, without tearing itself to pieces. Likewise for any craft trying to stop the rotor and use forward motion to generate the lift.

Theoretically couldn't it work if the craft had enough sufficient fixed wings to provide most of the lift necessary for level flight at transition speed?

Then you should be able to trim the rotor disk to near zero lift (beginning a relatively mild decent) before braking it to a stop. Once stopped, retrim it for forward lift and level off.

Mind you those big wings would likely do ugly thing to the airflow in vertical lift mode...

"Track performance and give bonuses to the people who manage to stop the intruders."

Ensure the bonus even goes to the average schmo hot-dog vendor who challenges somebody who doesn't have their ID showing. It's not a new strategy, but turning it into a game like this shifts cultures. Suddenly all the con-man defenses of "seriously, don't you know me?", "man, you're uptight, chill." or "Bob says it's okay" fall out the window to your "hey, I get $50 if you don't have a badge".

Not to pick on hot-dog vendors. They're probably more people savvy than most of your security team.

But like implementing bonuses for lines of code written, or number of bugs eliminated, be careful to put in safeguards against people gaming the system.

If all you do to "intruders" is ask them to leave it probably won't be long before someone gets the bright idea to ask a few friends to drop by and try to slip in. Or even for a coworker or two to "forget" their badge in order to split the reward.

This is ridiculous. Just pressurize the server room or whole building and be done with it. That layer of air would automagically reappear for the heads to glide over the platters.

Of course that means that the room pressurization would be a single point of failure for every hard drive you had. Lose pressure and every drive suffers a head crash simultaneously... Oops.

If I didn't need the storage volume I'd certainly prefer drives like SSDs that didn't require pressurization to work at that altitude. One less thing to go wrong. (Although the ability to pressurize the building when necessary to make maintenance / upgrades easier on the IT guys would be cool and useful)

I don't agree, and largely because you don't have a 'right' to drive within the United States, which is likely where they'll draw any legal help for challenges within the US. You also have limited rights in public places. What's the difference between a black box in the car and investigators measuring your travel speed using a camera from a gas station across the street? Or even in the same parking lot?

I'd say about the same difference between unmarked cars following your car around 24/7 and a GPS tracking device.

Yet the Supreme Court unanimously found that there was a significant difference in that scenario; that the later required a warrant (while the former didn't)

Sometime technology makes something so easy or so covert to widely accomplish that it, in practice, makes it effectively a change in kind not just degree. When that happens laws are written, or courts can find, that because something has become far easier to do that additional protections are required to maintain an acceptable level of practical freedom.

Requiring an expiration date on the ID also limits how long the person the ID is legitimately issued to could illegally vote in their old district/state after moving away.

The address on the ID was presumably accurate when issued; but who knows how long it'll remain accurate. Getting a new ID issued with the new address doesn't alter the old ID, and it's not like voting stations are checking any kind of ID revocation list.

What I really miss is the X-Com: UFO-style turn based strategies. I know there are some of the replicas (sort of) out there, but none of them even approaches the "X-Com: UFO Defence" in terms of gameplay. X-Com: Apocalypse was nice upgrade of the graphics and even had some gameplay improvements, but after that all sequels and clones kinda lost the point.

Were you aware that there's a new X-Com: Enemy Unknown game coming out this October from Firaxis (Sid Meyer's company, the ones who make Civilization).

From what I've seen it looks pretty true to the original game's play. As a fan of the first couple X-com games I'm really looking forward to it.

This is very cool, but the current super high bandwidth demonstration is being done with optical light over very short (1 meter) distances.

The article did point to an article from a couple months ago about the first ever OAM transmission; which was done with radio waves. But the antennas used look very directional and there was no mention of bandwidth.

Optical might be useful to further increase the speed of fibers, and highly directional radio might help for satellite broadcast or to compete with microwave relay towers. But requiring highly directional antennas, on both ends, isn't good for mobile wireless.

Hopefully we'll see another story soon where someone figures out how to detect and transmit OAM encoded radio waves from non-directional antennas.

If someone was claiming they hacked the Xbox/Live network and got access to credit cards, the comparison might be accurate. In this case, they're claiming they got credit card information from a device that doesn't have it.

And even if it did have it, I think there's better ways for bad guys to get credit card numbers then buying an Xbox one at a time, using a modding tool, grepping the filesystem and pulling out numbers.

It also sounds like there's no evidence from the article that the numbers were actually credit card numbers. I know every Discover card starts with 6011, but not all 16 digit numbers that start with 6011 are Discover cards, as an example. You also can't assume that any 16 digit number that starts with a 3, 4, or 5 and ends with a valid check digit is a credit card number.

Very true. And since Microsoft only appears to accept Visa, Mastercard, and AmEx (not Discover) for xbox live makes the chance that the investigators recovered a previous owner's Discover card number even less likely.

Wonderful, when the inevitable errors in the database occur you'll be stranded at some random gas station. Nothing in that article about how you could prove their database was incorrect or out of date.

At least if an officer ran your plate and stopped you you could provide proof of insurance, showing their database entry was wrong.

I'm with you up to 5 buffalos, but then you lose me.

"Buffalo buffalo buffalo buffalo buffalo" = "Bison from the city of Buffalo trick Bison from the city of Buffalo"
Please explain the last three Buffalo.

http://en.wikipedia.org/wiki/Buffalo_buffalo_Buffalo_buffalo_buffalo_buffalo_Buffalo_buffalo

So the last 3 are "who themselves trick Bison from Buffalo"

"I see your prohibition is against 'liquids'. Can I carry ice onboard?"

The agent didn't know. Asked his supervisor; she didn't know

That may have befuddled a particular agent, but it shouldn't have.
The TSA website lists a clear policy on frozen items

Frozen liquid items are allowed through the checkpoint as long as they are frozen solid when presented for screening. If frozen liquid items are partially melted, slushy, or have any liquid at the bottom of the container, they must meet 3-1-1 liquids requirements.

So those looking for surefire ways to befuddle TSA agents (for fun and amusement?) should probably look elsewhere.

This is a well known covert channel that has been covered in many security engineering books. One of the design principles for military computer networks is to keep the bandwidth of such a channel below 1 bit per second, although for very sensitive data it may need to be even lower.

Of course that type of leakage rate limiting defense can lose its effectiveness when dealing with encrypted data. If the encrypted data is output and can be recorded then all the bad guys need to sneak out is the corresponding key which is tiny in comparison.

At the rate you mentioned it only take about a minute to covert channel out the largest AES encryption key (256 bit). But that key might have been used to encrypt all the traffic sent in the last day (which you could've already intercepted and copied).

Even the largest common RSA key size (4096 bit) would only take a bit over an hour to output.

Don't most current methods of generating electricity pretty much break down into somehow generating heat to boil water to force steam to turn a turbine etc etc? Except for maybe hydroelectric, where you have gravity acting on water turning turbines AFAIK.

That depends on how you define "most current methods". In terms of watt/hours produced you're probably right; but in terms of number of methods not necessarily.

Nuclear, Coal, and (most?) Oil, are used to boil water to run steam turbines.
Natural gas peak load plants are usually gas turbines, no intermediate water boiling step.
Hydroelectric, as you mentioned, is water turbines
Solar thermal is boiling water (or other working fluids)
Solar-voltaic is basically direct electricity generation
Wind turbines obviously don't use boiling water, and neither do tidal power plants.
Geothermal plants are (mostly?) steam turbines.

Diablo 3 will have PVP. You can take your 'single player' character and pit it against your friends. Your single player character is your multiplayer character. There is no difference.

That's a design change that Blizzard choose to make.

Diablo II had PVP but there was still a difference between the online multiplayer character (battle.net) and the local character (single player/lan play). If you wanted cheat protections you played on battle.net, you're character was hosted on their servers and you had to have an active internet connection to play. If you wanted to play locally or just lan play with your friends you could use a non-battle.net character but you'd lose cheat protection.

You could never mix non-battle.net and battle.net characters so the only people affected by character or equipment edits were you and friends on your lan.

So Blizzard removes all that non-battle.net functionality in diablo III and tries to sell it as an improvement. And they wonder why there's a backlash...

The fact that they are discontinuing the roadster seems peripheral, although one may ask why they would discontinue them if they were profitable

I heard that the Roadster was always going to be a limited production run. Tesla got the frame and body from Lotus; paying them to run an production line that otherwise would have been temporarily surplus. But Lotus now has their own uses for that line so Tesla can't buy the chassis / body from them anymore.

Continuing roadster production now would drain their cash because they'd have to license the right to built the frame / body from Lotus then fund a new production line for it. Instead they want to focus on their next step, making a production line for the Tesla S sedan.