Forgot your password?
typodupeerror

Comment: Re:Will it be practical? (Score 1) 142

by benjamin_scarlet (#40438887) Attached to: "Twisted" OAM Beams Carry 2.5 Terabits Per Second

EM waves have frequency and polarization and phase. Their "orbital angular momentum" is some combination of these parameters so you can't increase bandwidth over what can be done using some combination of these.

Actually, I don't think their OAM is a combination of those parameters. It's about the spatial distribution of the phase around the axis of transmission.

Comment: Re:Here is a paper on this (Score 1) 142

by benjamin_scarlet (#40438773) Attached to: "Twisted" OAM Beams Carry 2.5 Terabits Per Second

It's using the spatial variation of the signal. In cylindrical coordinates (r,theta,z) aligned with the axis of transmission z, it uses different phases at different thetas. In particular, a bunch of superposed signals each with phase varying around the z axis as cos(i*theta) for i=0,1,2,... should stay conveniently distinct from transmitter to receiver.

I think the axis of transmission is baked into the idea pretty deeply - it's inherently unidirectional. I also think it's not robust to superposition: another such bunch of signals passing obliquely across the receiver would mess everything up.

Comment: Re:Too many qualifiers (Score 3, Interesting) 469

by benjamin_scarlet (#38551738) Attached to: Ford System Will Warn, Correct Lane-Drifting Drivers

The Prius Lane Keep Assist feature does steer a bit, gently - the wheel tends to drift toward it's best guess of the center of the lane. It won't drive for you, though: if you take your hands off the wheel it notices (I think it notices the absence of any applied torque over some reasonably short interval), sounds an alarm and turns off the feature.

Comment: Copyright? (Score 1) 94

by benjamin_scarlet (#36886892) Attached to: Crowdsourcing Ancient Egyptian Scrolls

"Images may not be copied or offloaded, and the images and their texts may not be published. All digital images of the Oxyrhynchus Papyri are © Imaging Papyri Project, University of Oxford. The papyri themselves are owned by the Egypt Exploration Society, London. All rights reserved."

They want help transcribing these documents, but don't want anyone to keep copies of the images? How rude.

Image

Students Banned From Bringing Pencils To School 426

Posted by samzenpus
from the watch-how-you-play dept.
mernilio writes "According to UPI: 'A Massachusetts school district superintendent said a memo banning sixth graders from carrying pencils was written without district approval. North Brookfield School District interim Superintendent Gordon Noseworthy said Wendy Scott, one of two sixth-grade teachers at North Brookfield Elementary School, did not get approval from administrators before sending the memo to all sixth-grade parents, the Worcester Telegram & Gazette reported Thursday. The memo said students would no longer be allowed to bring writing implements to school. It said pencils would be provided for students in class and any students caught with pencils or pens after Nov. 15 would face disciplinary action for having materials 'to build weapons.'"

Comment: a more effective approach to PE class (Score 1) 950

by benjamin_scarlet (#29434253) Attached to: Heart Monitors In Middle School Gym Class?

Heart rate monitors can and have been used in PE classes to grade students on their exertion rather than their capabilities. In stereotypes: the idea is to reward the nerd busting his ass rather than the jock breezing through, even though the jock might jog faster than the nerd can run.

The Internet

Experimental Fees Settle Royalty War For Internet Radio 270

Posted by samzenpus
from the pay-the-man dept.
S-100 writes "SoundExchange has reached an agreement for royalty rates with a consortium of Internet radio broadcasters. The parties are ecstatic that the issue is finally resolved, and that the new rates are below the previous 'death to Internet radio' levels that had previously been imposed by the CARB. According to NewsFactor, Pandora founder Tim Westergren proclaims that 'the royalty crisis is over!', and other large broadcasters are equally pleased. One unheard-from group is less likely to be pleased: small Internet radio broadcasters. Buried in the details are a new minimum royalty payment: $25,000 per year. So say goodbye to all of the small Internet radio stations that you have been listening to, as they will no longer afford to operate legally."
Security

Researchers Crack WPA Wi-Fi Encryption 311

Posted by CmdrTaco
from the now-they'll-know-my-secrets dept.
narramissic writes "Researchers Erik Tews and Martin Beck 'have just opened the box on a whole new hacker playground, says Dragos Ruiu, organizer of the PacSec conference. At the conference, Tews will show how he was able to partially crack WPA encryption in order to read data being sent from a router to a laptop. To do this, Tews and Beck found a way to break the Temporal Key Integrity Protocol (TKIP) key, used by WPA, in a relatively short amount of time: 12 to 15 minutes. They have not, however, managed to crack the encryption keys used to secure data that goes from the PC to the router in this particular attack. 'Its just the starting point,' said Ruiu."

It is not for me to attempt to fathom the inscrutable workings of Providence. -- The Earl of Birkenhead

Working...