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Διαβάστε το συνημμένο αρχείο (δελτίο τύπου) που αφορά :



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Μάλλον δεν το διάβασες καλά Bob...  :P


Off-topic: Ρίξε και μια ματιά στην διεύθυνση που έχει ως έδρα το ΑΜΔΘ.  ;)



Κ.Ι.Σ.

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Στο inet θα φευγουν μεσω proxy server ο οποιος θα λειτουργει σε εναν απο τους κομβους του δημου. Κοινως ρυθμιζεις τον ΙΕ (αντε και τον FF) να συνδεεται στο inet μεσω συγκεκριμενης ip και port.

http://www.technologyreview.com/blog/arxiv/24193/


The way signal strength varies in a wireless network can reveal what's going on behind closed doors.



It's every schoolboy's dream: an easy way of looking through walls to spy on neighbors, monitor siblings, and keep tabs on the sweet jar. And now a dream no longer...

Researchers at the University of Utah say that the way radio signals vary in a wireless network can reveal the movement of people behind closed doors. Joey Wilson and Neal Patwari have developed a technique called variance-based radio tomographic imaging that processes the signals to reveal signs of movement. They've even tested the idea with a 34-node wireless network using the IEEE 802.15.4 wireless protocol, the protocol for personal area networks employed by home automation services such as ZigBee.

The basic idea is straightforward. The signal strength at any point in a network is the sum of all the paths the radio waves can take to get to the receiver. Any change in the volume of space through which the signals pass, for example caused by the movement of a person, makes the signal strength vary. So by "interrogating" this volume of space with many signals, picked up by multiple receivers, it is possible to build up a picture of the movement within it.

In tests with a 34-node network set up outside a standard living room, Wilson and Patwari say they were able to locate moving objects in the room to within a meter or so. That's not bad, and the team says there is ample potential for improvement by increasing accuracy while reducing the number of nodes.

The advantage of this technique over others is, first, its cost. The nodes in such a network are off-the-shelf and therefore cheap. Other through-wall viewing systems cost in excess of $100,000. The second advantage is the ease with which it can be set up. Wilson and Patwari say that adding a GPS receiver to each node allows it to work out its own location, which should dramatically speed up the imaging process. Other systems have to be "trained" to recognize the environment.

Wilson and Patwari have even worked out how their system might be used:

"We envision a building imaging scenario similar to the following. Emergency responders, military forces, or police arrive at a scene where entry into a building is potentially dangerous. They deploy radio sensors around (and potentially on top of) the building area, either by throwing or launching them, or dropping them while moving around the building. The nodes immediately form a network and self-localize, perhaps using information about the size and shape of the building from a database (eg Google maps) and some known-location coordinates (eg using GPS). Then, nodes begin to transmit, making signal strength measurements on links which cross the building or area of interest. The received signal strength measurements of each link are transmitted back to a base station and used to estimate the positions of moving people and objects within the building."

That's ambitious, but if they do get their system to the point where it can be used like this, it raises another problem: privacy.

How might such cheap and easy-to-configure monitoring networks be used if they become widely available? What's to stop next door's teenage brats from monitoring your every move, or house thieves choosing their targets on the basis that nobody is inside?

Of course, in the cat-and-mouse game of surveillance, it shouldn't be too hard to build a device that disables such a monitoring network. But only if you know it's there in the first place.

There are fun and games galore to be had with this idea.

Researchers say they have created a special kind of paint which can block out wireless signals.




It means security-conscious wireless users could block their neighbours from being able to access their home network - without having to set up encryption.

The paint contains an aluminium-iron oxide which resonates at the same frequency as wi-fi - or other radio waves - meaning the airborne data is absorbed and blocked.

By coating an entire room, signals can't get in and, crucially, can't get out.

Developed at the University of Tokyo, the paint could cost as little as £10 per kilogram, researchers say.

Cost-effective security

The makers say that for businesses it's a quick and cheap way of preventing access to sensitive data from unauthorised users. Presently, most companies have to invest in complicated encryption software to deter hackers.

Speaking on the BBC World Service's Digital Planet programme, Shin-ichi Ohkoshi, who is leading the project, explained how the paint could have many uses beyond security.

"In a medical setting, you could transmit large volumes of data from a medical device, such as an endoscope, to a computer.

"By painting a solution containing our magnetic particles on the walls, you would quickly, and effectively, shield the room from stray electromagnetic radiation from outside."

While paints blocking lower frequencies have been available for some time, Mr Ohkoshi's technology is the first to absorb frequencies transmitting at 100GHz (gigahertz). Signals carrying a larger amount of data - such as wireless internet - travel at a higher frequency than, for example, FM radio.

"I'm working on a material that can absorb a larger range of frequencies. We are capable of making a paint that can absorb over 200 gigahertz."

He hopes that soon the technology could be woven into clothing.

"We're not sure about the true effects of electromagnetic waves, in this range, on the human body.

"We're assuming that excessive exposure could be bad for us. Therefore we're trying to make protective clothes for young children or pregnant women to help protect their bodies from such waves."

At the movies

The paint could also provide some much-needed relief during nights out at the cinema.
   
"Our current mobile phones work at much lower frequencies, around 1.5 gigahertz. But, our material can also absorb frequencies that low, so you could block phone signals from outside and stop people's phones ringing during the movie," he said.

As well as helping to keep the cinema quiet, the paint may also pave the way for higher quality screens.

"Movie pictures are beamed on the screen by the projector at the back of the cinema. But in the future, you could use a data link that works with millimetre waves.

"You would have problems with interference, unless you painted the wall and ceiling of the theatre with an absorbent material like ours.

"In fact, we've had an order from an American company keen to use our ink in its movie theatre - we've just sent them a sample."
'Nothing new'

Some security experts remain unconvinced by the paint.

"The use of electromagnetic shielding techniques are nothing new," said Mark Jackson, security engineer at Cisco UK. "They have been utilised by highly sensitive environments for many years."

Mr Jackson notes that while the paint may block eavesdroppers, it would not prevent other types of hackers or intruders.

"Paint that blocks RF based Wi-Fi transmissions does not in any way remove the need to ensure a robust security model is deployed," he added.

"Surely the thought of having to redecorate a building in order to provide Wi-Fi security is more costly & complex than security functionality available in even the cheapest of Wi-Fi access points?" he said.



http://news.bbc.co.uk/2/hi/technology/8279549.stm