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

by theckhd (#40454617) Attached to: "Twisted" OAM Beams Carry 2.5 Terabits Per Second
You keep repeating this, but... your IEEE paper does not "discredit" OAM or show that it's a "scam." Orbital Angular Momentum is a legitimate physical property of systems, both material (i.e. spinning tops, atoms, subatomic particles) and electromagnetic (light and radio waves). The IEEE paper is showing that doing so simply offers no major advantage over standard MIMO schemes. In fact, from the abstract of your paper:

We demonstrate that, for certain array configurations in free space, traditional MIMO theory leads to eigen-modes identical to the OAM states. From this we conclude that communicating over the sub-channels given by OAM states is a subset of the solutions offered by MIMO, and therefore does not offer any additional gains in capacity.

In other words, OAM is a perfectly legitimate technique for encoding data. It just happens to be a subset of what's already capable with MIMO. It's also worth noting that your paper discusses radio waves, and the OAM demonstration discussed in the submission is in the optical. There may be limitations that prevent certain MIMO techniques from being applicable to optical transmission, especially in guided-wave situations (i.e. optical fiber). In fact, the research group I worked with during my Ph.D. was looking at encoding extra information on single photons using OAM to increase the data capacity of quantum communication networks, a situation where MIMO is almost certainly not applicable.

It's worth noting that Alan Willner is no nutjob. He's worked at Bell Labs, has a chaired professorship at USC, is a fellow of IEEE, OSA and SPIE, and is an editor-in-chief for several reputable academic journals (JLT, Optics Letters, JSTQE). I had the pleasure of working with him on an unrelated project 5 or 6 years ago, and there's no reason to believe that he's trying to pull the wool over anybody's eyes. There's certainly no professional reason for him to do so, his CV speaks for itself: http://csi.usc.edu/faculty/willner.html

Comment: Re:If they can do this from earth... (Score 2, Informative) 165

by theckhd (#20462757) Attached to: Sharpest Images With "Lucky" Telescope
I think your suspicions are probably correct.

Lucky Imaging relies on the fact that every so often, a really high-quality image makes it through the atmosphere almost unperturbed (based on the Kolmogorov model of turbulence). While I don't know whether the same model can be applied to cosmic gas clouds, there may be another model that could accurately model the phase distortions those clouds impress upon a wavefront.

To achieve this one must take many very short-exposure (compared to the time-scale of atmospheric turbulence, or gas-cloud turbulence in the case we're considering) images of the source. However, distant (or dim) objects often require reasonably long exposure times in order to collect a large enough amount of light to be able to see the image. The problem with this technique may simply be that the exposure time necessary for the Lucky Image algorithm to work is too short to actually collect enough light to create a good image in the first place.
Movies

+ - First Pirated HD-DVD Hits BitTorrent

Submitted by
eldavojohn
eldavojohn writes "In light of recent events, the first pirated HD-DVD has been torrented. From the article, "The movie, Serenity, was made available as a .EVO file and is playable on most DVD playback software packages such as PowerDVD. The file was encoded in MPEG-4 VC-1 and the resulting file size was a hefty 19.6 GB." In more positive news for HD-DVD, it will be the only HD format to offer adult film as Sony has stated it will not allow porn to be released on Blu-ray."
Spam

Journal: EU Law and searching through *my* computers

Journal by mgcarley

It was a hard decision, but I think that this story should, oddly enough, come under the subject of spam, because thats where the whole problem really stemmed from. I'll try to keep it short, and as such will probably omit some details. Questions are welcomed. I apologize that my post may be quite "jumbled" - I'm trying to type as thoughts come to me, and occasionally may insert paragraphs here and there... but I'm sure you'll get there in the end.

On to the story:

Security

+ - Hard drive snafu has NBA star suing, fuming

Submitted by
coondoggie
coondoggie writes "All basketball player Bruce Bowen wanted was his hard drive fixed. What he got apparently is an invasion of privacy and a big mess. The Smoking Gun Website says the San Antonio Spurs forward hired a Texas company to fix but instead the repair company removed the machine's hard drive and sold the item — which contained confidential personal and financial information — to another customer. Bowen is now seeking over $2 million in damages from Computer Nerdz, the San Antonio company used to repair his Gateway computer. http://www.networkworld.com/community3/?q=node/147 53"
Education

+ - Significant Plant Blooming Research Faked

Submitted by
eldavojohn
eldavojohn writes "A Swedish research group has asked that its paper on how plants know when to bloom be retracted from Science Magazine which had previously heralded it as the third most important breakthrough of 2005. The Swedish university has placed the blame on a guest researcher from China who reported results that the research group was unable to recreate later. Tao Huang, the researcher in question, denies any wrong doing and claims the results are valid. From the article, Ove Nilsson who is the research professor from the Faculty of Science and Agriculture at Umeaa University told AFP, "Chinese researchers are under a lot of pressure from their country and are expected to produce a maximum amount of results in order to get a job." The research initially claimed to have proven that the florigen molecule that controls plant blooming plays the role of messenger in the process."

+ - I'm not a spammer

Submitted by tfinniga
tfinniga (555989) writes "A spammer has recently started using my domain name as "From:" addresses when sending out spam. I'm worried about my domain being blacklisted, and I'm annoyed by the bounces — I'm getting about 1000 bounce messages a day. Unfortunately, I give out a different email address to each site I visit: slashdot@example.com, paypal@example.com, amazon@example.com, etc., and the spammer is using a different address for each mail, so simple address filtering doesn't work.

What is the best way of avoiding being put on a blacklist, and dealing with the flood of bounces?"
Censorship

+ - US Censoring Internet?

Submitted by Anonymous Coward
An anonymous reader writes "It would appear that wikipedia viewers in the US see a "sanitized" version of some articles. For example Shaha Ali Riza (an important part of the Wolfowitz Scandal), both the Background and the Wolfowitz Scandal section are different for users in US locales (generally painting a much better picture of the people involved) than those presented to users in other locales (including, but not limited to, other english language locales such as Australia and the UK)."
Censorship

+ - VT Massacre - Blaming Video Games Commences

Submitted by Trails
Trails (629752) writes "Predictably, Jack Thompson is already blaming the VT massacre on video games [youtube.com]. In the video, Foxnews described JT as a "school shooting expert", before allowing him to rhyme off a littany of false or misleading claims about previous school shootings and how video games were the underlying factor of each. Kotaku.com has posted an article dissecting JT's claims here.

Elsewhere, Gamepolitics.com has posted a story about Dr. Phil blaming the massacre on video games while appearing on Larry King's show. His claim amounts to "video games can set off psychopaths", essentially taking as given the pre-condition that someone is a psychopath."
Data Storage

+ - Samsung Begins Shipping Hybrid Hard Drives

Submitted by
writertype
writertype writes "Samsung has become the first company begin shipping hybrid hard drives, we report on ExtremeTech. Unfortunately, there's no word yet (besides "soon") on when retail shipments will begin, or when (or if) 3.5-inch models will be available. Note that these are different than the ReadyBoost USB flash drives optimized for Vista; hybrid drives contain a smaller amount of flash, and work as a write cache for your notebook drive, extending battery life."

"Irrationality is the square root of all evil" -- Douglas Hofstadter

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