Friday, June 30, 2006
Old people does not hear this ring tone
sciences
The story starts with Compound, a security company, and their main product: the mosquito. An alarm which outputs an ultrasonic sound that only the young people can hear it. The idea is to prevent the gatherings of teenagers. An idea of Nicolas Sarkozy?
Here, it looks like adults won the game. But the idea has evolved and the mosquito was adapted into a ring tone for mobile phones! In United States of course, in UK and I guess soon everywhere in the world... 'Cause even Compund proposes its own, like the official one, called Mosquitone.
So, the fashion trick: receiving an SMS during the class, the teacher does not hear it, everyone laughs. You could use the vibrator but it's less funny anyway.
How does it work?
The drawing here above represents the spectrum of the audio frequencies a human being can hear. When he's young, this spectrum goes from 2000 to 18000 Hz, maybe more. But he gets old, the spectrum narrows. Not for everyone of course, but for most of people, it decreases as indicated above.
A test?
All right, but be sure to use good speakers and a correct PC sound-card, and first turn the volume down, then turn it up slowly. It can be surprising!
The sounds are not compressed (wav, not mp3). Otherwise, it's sure you could not here it...
4000 Hz, like piano :
12000 Hz, more than 60 you can't hear...
15000 Hz, more than 40...
17000 Hz, the Mosquitone's frequency:
20000 Hz, personally I can't hear:
Source : New-York Times, middle of June.
For those who do not know: One hertz (Hz) simply means "one per second" (1 / s); 100 Hz means "one hundred per second", and so on. The unit may be applied to any periodic event – for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz. Frequency of aperiodic events, such as radioactive decays, is expressed in becquerels.
Labels: sciences
Tatyana Simanava
anecdote
Can one speak about leading line for hOwGee? If so, it will be completely ridiculed by this small news, but who cares?Question: How the Russian model Tatyana Simanava was found on the motorway, with the broken arm, the dislocated shoulder, of scratches on her face?
Answer: she was on the bus of the agency Next Models, with her colleagues of the agency Next Models.
In this kind of luxury bus, there is, instead of usual seats, rooms to get undressed, a kitchen and a small living room. Tatyana wanted to go there, after a small break in the toilets. Living was on the left. The door on the right is a door to go ... outside. On the road. On the motorway!
That's no problem, Tatyana tried nevertheless and left the bus, at a speed of 40 mph.
Fortunately, she's all right now. That's why we can laugh ,finally.
And after all, she's a model, she had the rights to make-up herself in the toilets, no ?
source : New-York Daily News, two months ago.
Labels: anecdote
The hand controlled by the thought
exploits
Japanese researchers in the laboratories of Kyoto and de Saitama used the Magnetic Resonance Imaging (MRI) to control a robot-hand via the power of thought.During a demonstration, Yukiyasu Kamitani and his friends asked a guy to enter an RMI scanner, and to play Rock, Paper, Scissors. By moving the fingers, of course, mmh.
Scanner IRM records the activity of the brain when the subject makes the movements, and sends the data to a computer. After a short training period, the mechanical hand is able to repeat one of these 3 movements when the scanner-guy thinks of it.
This experience is regarded as an important opening in prosthetic research and operations ordered by the thought.
Klaus-Robert Mueller, a German researcher, has some (founded) doubts on the cost and the complexity of the system. Nevertheless, Yukiyasu is persuaded that applications in other fields will make it possible to use in every day's life.
For those who do not know:
- Magnetic resonance imaging (MRI), formerly referred to as magnetic resonance tomography (MRT) or nuclear magnetic resonance (NMR), is a method used to visualize the inside of living organisms as well as to detect the composition of geological structures. It is primarily used to demonstrate pathological or other physiological alterations of living tissues and is a commonly used form of medical imaging. MRI has also found many novel applications outside of the medical and biological fields such as rock permeability to hydrocarbons and certain non-destructive testing methods such as produce and timber quality characterization. More on wikipedia.
- Like the Go game and mahjong,rock-paper-scissors has been invented in China. According to a book called 五雜俎 written by 謝肇淛 at the end of the Ming's periodthe lords of the Han dynasty played a game cammplay called 手勢令 which is, in reality, rock-paper-scissors.
Labels: exploits
Intelligent touch-screen....
gadgets
Researchers at the MERL (Mitsubishi Electric Research Laboratories) developed an interactive screen computer which is able to differentiate its multiple users and to keep a log of their activities. Let's do it simply:
A touch screen, we see what it is: at the bank, at the station, using a navigation system... we interact with the computer by touching the screen with the finger.
A multi-touch screen is more rare, but a video demonstration ran on the Internet. It's the same, except that we can use many fingers and then, we could use it together.
We talk about that kind of screen, but this one can identify its users.
How? When somebody uses the screen, this one sends a negligible electric signal through the user's body. This signal is detected by a sensor on his seat. Hop, identified. And same thing for every user.
Why? Bah, video games or applications for meetings with security access. But just take another seat...
Source : the NewScientistTest, one month ago.
Labels: gadgets
Thursday, June 29, 2006
Cellars full of clandestine captchators
internetMore and more websites protect themselves from spam by using captchas, these twisted words we must re-type to prove we're human, not a machine.
More and more, these captchas are twisted, less and less we can read them, more and more it's irritable. And David Jeske, a technical director of Google, comments: "We know there's no perfect panacea, but we think this is a great tool to prevent malicious activity".
In Novembre 2005, the World Wide Web consortium published a paper informing that the captchas do not identify the human users correctly and can be thwarted by the intelligent programmers.
The workgroup noted, and that's my point, that some "spam companies" hire people to decipher captchas!
Could you imagine that? Cellars with tens of underpaid men, the eyes tired and continuously focused on 7 twisted characters that they must type on an old gray keyboard? Dark look and shining face, the whip waits for them if they do not reach their quota of captchas...
Fortunately, several Web sites explore new solutions, like audio captchas or simple enigmas. Good news for you, little captchator...
Source, because everything's true (except maybe the cellar) : The wall street journal online, beginning of the month.
For those who do not know:
A CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart, trademarked by Carnegie Mellon University) is a type of challenge-response test used in computing to determine whether or not the user is human. The term was coined in 2000 by Luis von Ahn, Manuel Blum, and Nicholas J. Hopper of Carnegie Mellon University, and John Langford of IBM. A common type of CAPTCHA requires that the user type the letters of a distorted image, sometimes with the addition of an obscured sequence of letters or digits that appears on the screen. Because the test is administered by a computer, in contrast to the standard Turing test that is administered by a human, a CAPTCHA is sometimes described as a reverse Turing test.
Labels: internet
A visual technique to extract the sound of vinyl records
exploits
The VisualAudio project was proposed by Stefano Cavaglieri of the Swiss National Record library in Lugano. The idea is based on 2 observations:
On a phonographic disc, the information is extracted via a needle that follows the side position of the furrow. If we observe this furrow by means of a microscope, we can see its radial curve. That means that the musical information is visible.
Many old discs, particularly the originals of the radiophonic productions, unique versions, are terribly damaged: this excludes any reading by a mechanics way, preferring a reading without contact.
4 steps:
The first one is the most critical: photograph the vinyl. Just once at the beginning of the project, then you can take the disc away. And as we would do for a good listening, it's necessary to clean it before, to withdraw dust and other foreign particle. Then the result is now on photographic film.
The second step : scan the picture. It is carried out by a device especially created for this purpose: it turns around the picture and scan it part after part. The result looks like this:
The third step is treating the image: correct the imperfections, determine the position and movings of the furrow. They also make other corrections thanks to physical knowledge thay have of a vinyl record. For example, the interpolation of the furrow in case it's cut.
And the last step: extracting the sound by means of computer, thanks to picture's information. This signal is treated one more time by filters band-pass in order to restore only the band-width of the master. Unfortunately, the website provides too few details on this step which I find the most interesting one.
Nevertheless, here is an example of the result:
And it's true, above the traditional crackings of a vinyl record, the noise is still important. The final objective of this project is to get the best signal-to-noise ratio. According to the article, the quality of a disc 33t will never be reached.
During the tests on the first prototype, they measured signal-to-noise ratios from 15 to 20 dB. This is explained by variations due to lighting (50Hz), vibrations of the rotary engine, and the presence of dust when the picture was shot.
Improvements are continuously made in order to eliminate these problems. The development of new algorithms to detect the furrow (subpixel estimate, filtering, modeling of the furrow,...) should also allow a significant improvment of the quality.
More simply, the ELP Laser Turntable is just a laser turntable for vinyl records. It reads the vinyls without touching them, with a laser, in order to keep it intact.
Source : the website of EIA-FR (no date)
For those who do not know : Signal-to-noise ratio (SNR) is an engineering term for the power ratio between a signal (meaningful information) and the background noise. Because many signals have a very wide dynamic range, SNRs are usually expressed in terms of the logarithmic decibel scale. In decibels, the SNR is 20 times the base-10 logarithm of the amplitude ratio, or 10 times the logarithm of the power ratio.
Labels: exploits
Wednesday, June 28, 2006
Invisibility : The Feasibility Study
exploits
A few weeks ago, we wrote something about an invisible clothing, created in Japan. Invisible was over-exaggerated, since you had to look through a lens ... to see nothing!Anyway, the real invisible clothing is coming soon:
John Pendry, David Smith et David Schurig, a beautiful group of English and American scientists, have established a theorical and mathematical model describing a device of invisibility.
How does it work? Look at the photograph here on the left. The invisibility would be created by a distortion of the rays of light. Their trajectory is curved in order to circumvent the object to be masked. The rays then take, behind the object, the trajectory which they would have had if the object had not been there.We could also make an analogy with the river and an obstacle: water circumvents the obstacle and the current takes its initial shape just afterwards. Except that, in our case, water is electromagnetic waves (the light), and the obstacle is the invisible object.
Thus, this object should be covered with a material which could deviate the electromagnetic waves in this way. Paper describes this object as being a sphere or a cylinder coated with a sheath having this property. It is very theoretical and yet, a demonstration is foreseen at the end of 2007.
And guess who is interested the most by this (potential) future invention?
Exactly .. as usual ... the famous DARPA.
source: stuff, one month ago.
for those who do not know: Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength.Due to the wave-particle duality of matter, light simultaneously exhibits properties of both waves and particles. The precise nature of light is one of the key questions of modern physics. To be continued on wikipedia.
Labels: exploits
Tuesday, June 27, 2006
The tracking USB stick
gadgets
Track Stick is a small USB stick USB that holds in the pocket. Keep it with you all the time and it will record places, time, dates, speeds, directions and altitudes at regular frequency. With more than 1 Mb of memory, it can record several months of your life.Track Stick receives the signals of 24 satellites. With this information, it can precisely compute its position (and then yours) everywhere on the planet with an accuracy of 15 meters. It can also calculate how long you stay inside, i.e. when it does not receive any GPS signal.
You didn't need it? TrackStick dit it, and now you want it :/
Moreover, the history can be exported to these formats…
- RTF
- HTML : (really) beautiful pages with graphics and google maps
- CSV : columns separated with a comma, can be exported to Excel
- and overall KML, the file's format of Google Earth !
Labels: gadgets
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