Disk encryption works by keeping a encryption ‘key’ in memory while the computer is in use. This key is linked to your account and Windows won’t give up your key to anyone else unless they have your account password. Unfortunately, there is a chink in the armour. It was previously thought that when the power is cut, all data in the computer’s DRAM (dynamic random access memory) automatically vanished. However, Professor Edward Felten and his team at Princeton University have discovered that data remains intact for a few minutes after the computer is turned off, and can last for hours if the memory is cooled. This opens up a new channel for attack:

1. Steal a laptop that is running on sleep mode.
2. Insert a flash drive containing a customized rogue operating system.
3. Hard reboot the laptop. The rogue OS is loaded and it proceeds to grab your encryption key from memory.

With the encryption key, the attacker can now read all your files. Solution: don’t go to the café when hi-tech theives are about.

Watch the video to learn more:

Watch this amazing video of Frenchman Jean-Yves Blondeau (nicknamed Rollerman) and his Buggy-Rollin suit. As he hurtles at incredible speed down luge runs and the streets of France, I can’t help thinking that Blondeau is an anime character come to life.

Incredibly, he works without any preliminary sketching. This is strongly reminiscent of Salieri’s description of Mozart’s manuscripts in the film Amadeus, “[...] they showed no corrections of any kind. Not one. He had simply written down music already finished in his head. Page after page of it as if he were just taking dictation. And music, finished as no music is ever finished. Displace one note and there would be diminishment. Displace one phrase and the structure would fall.”

Stephen’s art is an almost exact reproduction of what he’s seen. The church of St Peter’s, the narrow side-streets, and even the intricate Colosseum are perfectly captured.

The robot stands 152cm (5 ft) tall and has 17 joints in both of its hands and arms. The demonstration on 6th December 2007 wasn’t intended to showcase Toyota’s up-and-coming line of virtuoso violinist robots, but to demonstrate the dexterity now possible. Toyota plans to roll out these robots for assistance with domestic duties and nursing and medical care. As such, they will be known as “partner robots”.

Ask yourself this question: what exactly does a decibel measure? If you’re thinking “loudness of sound”, then you’re on the right track, but there’s more to it.

Any quantity can be measured on a decibel scale, but decibels are most useful when they describe an underlying quantity that varies over a vast range. Let’s take the example of “loudness”; this is formally measured by sound pressure. For example, the sound of a rifle being fired at a distance of 1m has a sound pressure of 200 Pa, whereas rustling leaves results in a sound pressure of 6 × 10^-5 Pa (that’s 0.00006 Pa in decimal). We can hear both these sounds, though there is a factor difference of over a million in the measurement. However on the decibel scale, the rifle hits 140 dB and the leaves rustle at 10 dB, a much more manageable number range.

If you have some mathematical training, you’ll know that any large number range can be comfortably handled using logarithms. By definition, if 10^a=b, then log b = a. Here are some examples:

To start with, you might begin by simply taking the logarithm of the underlying quantity. So let’s define “logbels” in this manner. For sound pressure as above, we’d have that

Not a bad first attempt, but it suffers from two deficiencies. The first is that the logbel scale is dependent on the underlying units. For instance, if we’d chosen to measure sound pressure in pounds per square inch, we’d end up with different logbel units. The second problem is that the resulting numbers are difficult to interpret. Rustling leaves give minus 4.22 logbels.

A solution to both problems is to chose a reference measure and define decibels as the logarithm of the ratio of the underlying quantity with respect to the reference measure. Let’s revisit sound pressure. By convention, the underlying unit is Pascals squared, and the reference measure, X₀, is chosen to be the auditory threshold at 2 kHz (that’s 2 × 10^-5 Pa or 4 × 10^-10 Pa²). Suppose we now measure the actual sound pressure and find it to be X Pa². The decibel is then defined as

So with this new definition, the auditory threshold is 0 dB, placing the rustling leaves at 10 dB. An important property of logarithmic scales is that adding a constant to a number on the scale corresponds to multiplying the underlying quantity by a (different) constant. In the decibel scale, an increase of 3 dB corresponds to a doubling of the underlying quantity. The difference between leaves and a rifle is 130 dB, a factor difference of 2^130/3. That’s about 2⁴³ ≈ (2¹⁰)⁴ 2³ ≈ 8 × (10³)⁴ = 8 × 10¹². Remember, this is in squared units, so the ratio of the Pascal measurements is √(8 × 10¹²) ≈ 3 × 10⁶, as before.

Wait a minute, didn’t I say that decibels weren’t just for sound? Well it should be clear from the formulation above that any quantity can be measured using a decibel scale, but decibels are most useful for measurements where human (or other) perception varies logarithmically with the underlying quantity. A common use for decibels is in measuring power in electrical circuits or of radio signals. Typically, the reference value will be a milliwatt, giving rise to the dBm (m for milliwatts). For example, if you have access to a wireless network, your wireless adapter may indicate received signal strength in dBm, here -50 dBm indicates an excellent signal, whereas -80 dBm is a poor signal.

There are other popular scales that are logarithmic in nature. Perhaps the best known is the “apparent magnitude” scale for measuring the brightness of stars. Our perception of brightness is logarithmic with respect to the received electromagnetic flux, leading to the following definition of apparent brightness:

where F is the flux and C is an appropriate constant. Note the negative sign in front of the logarithm. This means that smaller magnitudes correspond to brighter stars.

That future is not so far off, thanks to the efforts of Emotiv Systems and NeuroSky, two companies taking the medical technology of EEG and transforming it into a platform for mind-controlled gaming. However, some experts are wary that this might be a dangerous misapplication of a therapeutic tool.

As pictured below, their devices work by reading brain waves through a set of carefully positions electrodes. The intensity of the brain waves can then be used as a controlling variable in a game. In medicine, the idea has already been tested with quadriplegics, allowing them to operate switches and wheelchairs by mind-control.

Another medical application is in the treatment of mental disorders. Smart BrainGames has developed a racing game in which the user increases their speed by becoming calmer. However, this is solely intended for relaxation and “muscle re-education”, not for entertainment.

The crux of the scientific concern over mind-control games is based in the possibility that such games could lead to altered states outside the game scenario. An an example, it’s possible that a driver could remain excessively calm in real live, leading to slower reflexes on the road.

Speaking in Wired, Emotiv’s CEO Nam Do defended his technology, distancing it from the neurofeedback tools used for the treatment of mental disorders: “Emotiv’s technology is based on an entirely different fundamental concept, developed and researched extensively by our own team of scientists, which does not involve the use of conventional bio- or neurofeedback at all, so the concerns do not apply. There is no two-way interaction, and the technology does not require the user to train their brain to get into a predetermined state in any way.”

The technology:

Emotiv’s headset is very sophisticated, employing 18 electrodes and is able to detect emotional states, facial expressions such as smiles and winks, and even focussed thoughts, such as the will to move a particular object. They’ve also developed an API to allow Emotiv headsets to work with existing games. Nam Do envisions that this will immediately lead to its uptake on the Xbox 360 and the PS3, and that it could later be integrated into multiplayer worlds such as Second Life.

Neurosky goes to the other extreme and uses only one electrode, leading to a very cheap, $20 headset rather than Emotiv’s several hundred dollar price tag. Though less accurate, it may well be enough, at least according to Klaus-Robert Müller, a computer scientist at the Fraunhofer Institute in Berlin whose work suggests that one electrode is sufficient to produce useful data.