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Hrmmm.... um, well, maybe, but if so, the main picture on the featured site is NOT what the site is talking about.

A hovercraft has a plenum chamber, i.e. a cushion of air created by a vacuum or fan blowing DOWN into an enclosed, flexible area, usually called the "skirt". See this picture or these for the typical setup.

What this seems to be is simply an airplane without landing gear. Wow.

note: you can read more about hovercrafts here - though it's aimed for a younger audience.

Reductio ad absurdum. I expect that the two dials on my microwave operate the same way. I expect that every car I drive have controls that operate closely to each other. I expect that the remote I use on the couch be able to drive my VCR, DVD, Satellite and TV.

The reason for dark matter is that by using our models, the universe ought to fling itself apart pretty quickly. The delicate strands of galaxies... they're simply not dense enough.

Thus the reason for the theoretical extrapolation of dark matter. If 90% of the universe's mass was unseen, THEN the universe would have enough density to keep itself together.

Another theory, MOND is that Newton's Law of "For every action there is an equal and opposite reaction" does not apply to extremely low accelerations.

Some credence was lent to MOND by the Boomerang findings last year. The amplitude of the second peak [in the power spectrum of the cosmic microwave background] was that predicted by Stacy McGaugh, to fit with MOND, and too low to match the theories of Dark Matter.

I thought the analogy with 1950s comptuers was interesting, but I think a more appropriate analogy would be 1930s computing -- we're still a long way off.

And did anyone else note that Reynolds of the article didn't cite any sources for these "rumors" of a "nanotechnology clampdown"? Bad journalism + ignorance = hysteria.

foregone publishing in favor of taking this public immediately.

Of course still by far the biggest danger of eating crap like fries is the cholesterol and fat. Everyone knows that fries aren't the greatest for your health. It shouldn't take a carcinogen scare story like this one keep people from eating too much unhealthy food.

I also would like to point out that we eat all sorts of carcinogens. There are so many carcinogens out there that I don't worry about it when they discover a new one.

Here are a few:
1. Comfrey
2. Sassafras (in higher-quality root beer)
3. Some meat preservative. Forgot what it's called.
4. The sun. Probably the biggest carcinogen of all.
5. Numerous body compounds
6. Burned meat
7. Benzene
8. Cadmium
9. Carbon Black
10. Formaldehyde
11. Gasoline
12. Nickel
13. Quartz
14. Radon
15. Mineral Oil
16. Urethane
17. Wood Dust.

Just about everything is carcinogenic. I, personally, don't worry about it. I can't isolate myself from all of these carcinogens anyway. A more complete list is available here.

I just hope this doesn't lead to tobacco-industry style class action lawsuits.

I hate people like that. For example, I am no fan of big tobacco, but if you smoke, it is your fault! Everyone has known for years that tobacco is harmful and addictive. The tobacco companies shouldn't be sued for your idiotic actions. I just think tobacco should be taxed even more heavily. Anyway, im drifting offtopic.

Funny you should mention this. Did you know you can get an approximate figure of the speed of light using only a common microwave oven, marshmallows and a ruler? Try this experiment:
http://www.physics.umd.edu/ripe/icpe/newsletters/n 34/marshmal.htm

Does this mean that only Microsoft products will be used at the University of Maryland, College Park?

No, the agreement is not exclusive. Participation for faculty and staff is voluntary. Faculty and staff members have the freedom to use whatever software they personally choose; however, for the next three years they also have the option of participating in the MSEA.

The HCIL at the University of Maryland is another strong entry in the list of schools doing HCI work.

This actually isn't entirely true. Having an oxygen rich atmosphere is not sufficient; the atmosphere must also be humid and hot. Primarily, this is required because (as the parent post pointed out) their circulatory system is comprised of oxygen carrying trachea rather than blood carrying arteries and veins; as a result, the oxygen must pass directly through the tracheal membranes into the cells behind them.

This doesn't happen easily unless the air is humid, rather for the same reason our lungs (which transfer oxygen to the blood in a similar manner) must be moist. This is why we so often see monstrous bugs in humid (tropical) areas, and less so in deserts.

The moisture is much more important than the oxygen. Consider the monster millipede Arthropleuridea , which, during the Silurian Era, grew in excess of two meters. During that era -- some 55 million years before the apperance of the dinosaurs, over 300 million years ago -- Earth's atmosphere was far less oxygen-rich than it is now; yet many grotesquely large insects existed at that time -- many more than today. The atmosphere was also hot and tropical, and the excess humidity allowed these insects to flourish.

They could have been more careful about things like the memory model.

There is nothing wrong with the C#/CLR "memory model". By default, it is safe, just as in Java. If you write an unsafe model, the memory model is unsafe, just like it is in Java. Oh, you say, Java doesn't have unsafe modules. But it does. They are called "JNI". The only difference to C#'s unsafe modules is that JNI is less efficient and harder to program. (Both Java's and C#'s security models label unsafe code as such.)


That isn't what he means by memory model. It has nothing to do with safe vs unsafe code. It has to do with how multithreaded programs are supposed to behave when running under different VMs on different platforms.

The model for .NET is awful by comparison to proposed changes in the Java specification, but the current Java spec is equally awful. Gosling was afraid .NET would have a decent specification.

Check out this for a discussion of JSR 133, which discusses proposed changes to Java's memory model.

An example of research in user interfaces is Denim which aims to marry the advantages of old fashioned pen+paper design with the convenience of having the computer handle the details. The idea is to allow the designer to freely sketch with a tablet but also add hyperlinks between sketches as the design progresses. There's a sample of the generated mockup, but really the videos on the page linked above are really neat. They show a person using a tablet to do a sample design. The software also incorporates some other modern interface ideas such as the zoomable UI and the pie menu.

Ah, the skiplist. Every time algorithms come up, the skiplist is not paid nearly enough attention.

I know that I've posted this URL once to this article aready, but skiplists are practically ignored, compared to how nifty they are. No balanced tree has a right to exist (except perhaps B-trees because the mesh nice with hardware) with skiplists around:

And I'd like to add 2 more nifty and somewhat ignored algorithms: the Burrows-Wheeler Transform and the Discreet Cosine Transform. Burrows-Wheeler is what gives us bzip, and Discreet Cosine is what gives us JPEG and MPEG. Heck, while I'm on a compression kick, lets add MTF (move-to-front) and Huffman Codes.

My personal favorite is the skiplist. O(ln n) insert, search, and delete in the average case. Simple to understand, has good constant factors, doesn't require maintence (unlike trees). Really, what more could you want?

Here's the paper:

My personal favorite is the skiplist. O(ln n) insert, search, and delete in the average case. Simple to understand, has good constant factors, doesn't require maintence (unlike trees). Really, what more could you want?

Here's the paper:

Correction to my above post- the first answer, about the protons+electrons combining, seems to be correct. For more info, check out Introduction to neutron stars.

Most often users frustration is vented on the keyboard (http://lap.umd.edu/Computer_Rage/). Maybe we would see people getting hurt banging on desks or dashboard..

I know, that friggin asteroid is huge! That's exactly what I was thinking when I looked at that thing. That thing would be a planet killer for sure. If something that big hit the earth with any velocity, it would immediately destroy the atmosphere.

The earth's diameter is around 7600 miles, and even a conservative estimate of the size of that asteroid would put it at no smaller than 10% of that, or 760 miles (or 1225 km) across.

Just for the hell of it, I went to http://janus.astro.umd.edu/astro/impact.html and threw in such a beast travelling at 20km/s, and the resultant impact is calculated at 109476 billion megatons.

Marvin the Martian's Conclusion: Oh dear! It looks like all Earth's oceans are boiling! Earth will have a steam atmosphere for thousands of years!

My Conclusion: They really need a new drawing to stop freaking people out. :)

Incidentally, go run the figures at the site above and look at the picture that goes with the results. Look familiar?

I know, that friggin asteroid is huge! That's exactly what I was thinking when I looked at that thing. That thing would be a planet killer for sure. If something that big hit the earth with any velocity, it would immediately destroy the atmosphere.

The earth's diameter is around 7600 miles, and even a conservative estimate of the size of that asteroid would put it at no smaller than 10% of that, or 760 miles (or 1225 km) across.

Just for the hell of it, I went to http://janus.astro.umd.edu/astro/impact.html and threw in such a beast travelling at 20km/s, and the resultant impact is calculated at 109476 billion megatons.

Marvin the Martian's Conclusion: Oh dear! It looks like all Earth's oceans are boiling! Earth will have a steam atmosphere for thousands of years!

My Conclusion: They really need a new drawing to stop freaking people out. :)

Incidentally, go run the figures at the site above and look at the picture that goes with the results. Look familiar?

Here is my web page detailing some of the steps I go through to create a linux on a disk. I am working on putting more details on soon but I think it still gives a good introduction.

If you want to make your custom Linux disc, take a look at this step-by-step howto:
http://wam.umd.edu/~kefferb/floppy.html

This was my final year project thesis. Just remember the golden rule unstructured 2 structured == convert 2 XML I wrote a [very bad] program in C++/Perl/tcsh IPC=pipes to add XML tags to English, and then index them into a search engine which would use the lingual data stored in the XML tags to help the search.

NIST does a MASSIVE competition on this annually. I don't want to be an XML-buzzword whore <Arnold Schwarzenegger accent> (XML commando eats Green berets, C++, Java, Perl, COBOL for breakfast)</Arnold Schwarzenegger accent> but you can't beat XML for easily converting anything that you can make sense out of into computer readable format. Real h3cKoRs use SGML, but us underlings have to stick with things we can understand like XML. As for expandability, if we want to encode something else into the document, then just tag-it-and-go

It took me 200 hours to fish out all these links (before the Google days), I don't want anyone to have to waste as much time as I did feeding the search engines exotic foods. It's a year old so pardon me for the odd broken link, armed with these you could probably turn jello into XML ;-)

My favourite bookmarx
PROJect[21 links]
Beginners' Guide[13 links]
Berkeley Linguistics Dept. Course Summaries, general stuffzzzzzzzzzzzzzzCryptic IR Vocabulary defined
Explanations of weird words like hypernym zzzzzzzzzzzzzzHow do we produce and understand speech
How Inverted Files are Created - Univeristy of Berkeley zzzzzzzzzzzzzzNLP Univ. of Indiana, very good basics e.g. word sense d
Simple langauge - useful.... zzzzzzzzzzzzzzWhat is Natural Language Processing, links
What is POS tagging........ zzzzzzzzzzzzzzWord Sense Disambiguation defined
Word Sense Disambiguation in detail, scroll down far zzzzzzzzzzzzzzWord Sense Disambiguator - LOLITA (tested at MUC-7 and SENSEVAL competition as best)
XML for the absolute beginner

HTML, XML stuff + parsers[19 links]
Apache plug-in that uhhh does stuff with XML zzzzzzzzzzzzzzConvert COM to XML
convert XML, HTML to Unix pipeable formats zzzzzzzzzzzzzzconverters to and from HTML
expat XML parser zzzzzzzzzzzzzzHTML Tidy - converts HTML 2 XML + source code!!
Parse DB (RDBMS, whatever) to XML zzzzzzzzzzzzzzPerl-XML Module List
PHP Manual XML parser functions - what the hell are they talking about, PHP Virtual M... zzzzzzzzzzzzzzPublic SGML-XML Software
Pyxie - XML Processor for Python, Perl, etc. zzzzzzzzzzzzzzSGML+XML tools.org
The XML Resource Centre - massive number of links zzzzzzzzzzzzzzW4F wrapper - wrapper converts XML to HTML
XFlat - convert flat file into XML zzzzzzzzzzzzzzXML Parsers and other XML stuff
XML.com - Parsers, etc. zzzzzzzzzzzzzzXML-Data Catalog System - uhhhh looks close
XTAL's general converter - convert anything 2 XML

other Background[8 links]
Is Linux ready for the Enterprise, scalable... zzzzzzzzzzzzzzLinux reliability
Linux Versus Windows NT, Mark(sysinternals bloke) zzzzzzzzzzzzzzPC reliability (pcworld)
SPEC - Standard Performance Evaluation Corp. zzzzzzzzzzzzzzSystems benchmarks
TPC - Transaction Processing Performance Council zzzzzzzzzzzzzzUnix Beats Back NT In EDA Workstation Arena
Proper TREC(-8) QA systems[2 links]

pg. 387 LIMSI-CNRS pretty deep parsing[2 links]
More links....
NLP, IR links - lots to corpii, etc.

pg. 575 U. of Ottawa and NRL (shit system, got 0%)[1 links]
LAKE Lab
pg. 607! University of Sheffield (crap system, but OPEN SOURCE!)[2 links]
GATE - FREE IE app w`source code
LaSIE - ER, coreference, template (cv)

pg. 617 Univ of Surrey (inconclusive matches)[2 links]
System Quirk - Or is this their search system..... Hmmmmmm
Univ of Surrey - pointers (hopefully this is their WILDER search system...)

SMU - Pg. 65[1 links]
Natural Language Processing Laboratory at SMU

Textract[2 links]
Cymfony - Technology
Textract - State of the Art Information Extraction

Xerox uhhhhh maybe[1 links]
Xerox Palo Alto Research Center
(OVERVIEW) 1999 TREC-8 Q&A Track Home Page
NLP bloke, Univ Sussex


Tcl-Tk[4 links] Tcl tutorial
Tcl-Tk Contributed Programs Index
Tcl-Tk Resources, sources
TclXML - manipulating XML using Tcl-Tk
Artificial Natural Language - Is this what I'm trying to parse into...
Comparison of Indexers - Prise vs. Inquery vs. MG, etc.
Eagles - Language Engineering Standards
Language Technology Group - lots of modules!
LDC - Linguistic Data Consortium, lots of corpora
Lexical Resources
Links 2 resources, indexers.....
Lots of IR stuff, University of uhhh
Managing Gigabytes Indexer
Managing Gigabytes Manuals and stuff
Htdig search system
NLP & IR (NLPIR, NIST) Group
OVERVIEW OF MUC-7-MET-2
Perl XML Indexing - XML search engine type thing
Phrasys Language Processing Software Components (money)
QA HCI bullshit
SIGIR - TREC-type thing, resources
SMART indexer system documentation
Text REtrieval Conference (TREC) Home Page
The Natural Language Software Registry
Thunderstone IE and IR products
WordNet - FREE DOWNLOADABLE lexical English database

Page created with URL+, nice utility for working with internet shortcuts

This was my final year project thesis. Just remember the golden rule unstructured 2 structured == convert 2 XML I wrote a [very bad] program in C++/Perl/tcsh IPC=pipes to add XML tags to English, and then index them into a search engine which would use the lingual data stored in the XML tags to help the search.

NIST does a MASSIVE competition on this annually. I don't want to be an XML-buzzword whore <Arnold Schwarzenegger accent> (XML commando eats Green berets, C++, Java, Perl, COBOL for breakfast)</Arnold Schwarzenegger accent> but you can't beat XML for easily converting anything that you can make sense out of into computer readable format. Real h3cKoRs use SGML, but us underlings have to stick with things we can understand like XML. As for expandability, if we want to encode something else into the document, then just tag-it-and-go

It took me 200 hours to fish out all these links (before the Google days), I don't want anyone to have to waste as much time as I did feeding the search engines exotic foods. It's a year old so pardon me for the odd broken link, armed with these you could probably turn jello into XML ;-)

My favourite bookmarx
PROJect[21 links]
Beginners' Guide[13 links]
Berkeley Linguistics Dept. Course Summaries, general stuffzzzzzzzzzzzzzzCryptic IR Vocabulary defined
Explanations of weird words like hypernym zzzzzzzzzzzzzzHow do we produce and understand speech
How Inverted Files are Created - Univeristy of Berkeley zzzzzzzzzzzzzzNLP Univ. of Indiana, very good basics e.g. word sense d
Simple langauge - useful.... zzzzzzzzzzzzzzWhat is Natural Language Processing, links
What is POS tagging........ zzzzzzzzzzzzzzWord Sense Disambiguation defined
Word Sense Disambiguation in detail, scroll down far zzzzzzzzzzzzzzWord Sense Disambiguator - LOLITA (tested at MUC-7 and SENSEVAL competition as best)
XML for the absolute beginner

HTML, XML stuff + parsers[19 links]
Apache plug-in that uhhh does stuff with XML zzzzzzzzzzzzzzConvert COM to XML
convert XML, HTML to Unix pipeable formats zzzzzzzzzzzzzzconverters to and from HTML
expat XML parser zzzzzzzzzzzzzzHTML Tidy - converts HTML 2 XML + source code!!
Parse DB (RDBMS, whatever) to XML zzzzzzzzzzzzzzPerl-XML Module List
PHP Manual XML parser functions - what the hell are they talking about, PHP Virtual M... zzzzzzzzzzzzzzPublic SGML-XML Software
Pyxie - XML Processor for Python, Perl, etc. zzzzzzzzzzzzzzSGML+XML tools.org
The XML Resource Centre - massive number of links zzzzzzzzzzzzzzW4F wrapper - wrapper converts XML to HTML
XFlat - convert flat file into XML zzzzzzzzzzzzzzXML Parsers and other XML stuff
XML.com - Parsers, etc. zzzzzzzzzzzzzzXML-Data Catalog System - uhhhh looks close
XTAL's general converter - convert anything 2 XML

other Background[8 links]
Is Linux ready for the Enterprise, scalable... zzzzzzzzzzzzzzLinux reliability
Linux Versus Windows NT, Mark(sysinternals bloke) zzzzzzzzzzzzzzPC reliability (pcworld)
SPEC - Standard Performance Evaluation Corp. zzzzzzzzzzzzzzSystems benchmarks
TPC - Transaction Processing Performance Council zzzzzzzzzzzzzzUnix Beats Back NT In EDA Workstation Arena
Proper TREC(-8) QA systems[2 links]

pg. 387 LIMSI-CNRS pretty deep parsing[2 links]
More links....
NLP, IR links - lots to corpii, etc.

pg. 575 U. of Ottawa and NRL (shit system, got 0%)[1 links]
LAKE Lab
pg. 607! University of Sheffield (crap system, but OPEN SOURCE!)[2 links]
GATE - FREE IE app w`source code
LaSIE - ER, coreference, template (cv)

pg. 617 Univ of Surrey (inconclusive matches)[2 links]
System Quirk - Or is this their search system..... Hmmmmmm
Univ of Surrey - pointers (hopefully this is their WILDER search system...)

SMU - Pg. 65[1 links]
Natural Language Processing Laboratory at SMU

Textract[2 links]
Cymfony - Technology
Textract - State of the Art Information Extraction

Xerox uhhhhh maybe[1 links]
Xerox Palo Alto Research Center
(OVERVIEW) 1999 TREC-8 Q&A Track Home Page
NLP bloke, Univ Sussex


Tcl-Tk[4 links] Tcl tutorial
Tcl-Tk Contributed Programs Index
Tcl-Tk Resources, sources
TclXML - manipulating XML using Tcl-Tk
Artificial Natural Language - Is this what I'm trying to parse into...
Comparison of Indexers - Prise vs. Inquery vs. MG, etc.
Eagles - Language Engineering Standards
Language Technology Group - lots of modules!
LDC - Linguistic Data Consortium, lots of corpora
Lexical Resources
Links 2 resources, indexers.....
Lots of IR stuff, University of uhhh
Managing Gigabytes Indexer
Managing Gigabytes Manuals and stuff
Htdig search system
NLP & IR (NLPIR, NIST) Group
OVERVIEW OF MUC-7-MET-2
Perl XML Indexing - XML search engine type thing
Phrasys Language Processing Software Components (money)
QA HCI bullshit
SIGIR - TREC-type thing, resources
SMART indexer system documentation
Text REtrieval Conference (TREC) Home Page
The Natural Language Software Registry
Thunderstone IE and IR products
WordNet - FREE DOWNLOADABLE lexical English database

Page created with URL+, nice utility for working with internet shortcuts

Vannevar Bush, As We May Think (July 1945)

Ben Schneiderman, Codex, Memex, Genex (December 1997)

Henry Jenkins, Information Cosmos (April 2001)

What I would do is compile a stripped down kernel, use busybox for most system apps, and have your init scripts call the tinyX server and then instead of using a window manager have the startx script start galeon in full screen mode using tabs instead of separate windows for popups. The only difficult part may be getting mozilla or galeon compiled because of the gtk requirements) You could try the Xlib mozilla port perhaps.

For a little bit of info on how I have done a similar project take a look at my linux on a floppy page.

For those looking for instructions on building a linux floppy take a look at some documentation I made up while working on my own.

I had not found any good linux floppy firewall distributions running 2.4 the kernel so I figured out how to do it myself. This document doesn't include the instructions on how to include iptables but I will be adding that soon (it isn't too difficult).

I was going to go for a rabit/antelope combo...

How about a basselope instead?

Hardness increases with toughness not necessarily vis versa.

Think of it roughly in these terms:

A hardness contest between two materials consists of trying to scratch one with the other. The one scratched is harder.

A toughness contest between two materials consists of trying to break one material with the other. The one broken wins.

I've seen a few comments asking where to find old equipment and one comment made a great suggestion--the local university. Those of you who are living in the Washington DC metropolitan area should be happy to know that the University of Maryland, College Park hocks their stuff to the public. Their operation is called Terp Traders. I just checked and they had a few DECs available ($50 or less). Goto Inventory-->Data processing-->CPU. Sorry, I know some of you are terps yourselves and wanted to keep this a secret all to yourselves, but I'm a karma whore. Enjoy! And, go Terps Basketball!

In actuality, old systems like the CDC6600s used to have very similar constraints, where reordering instructions could give you signifigant performance improvements. Quoting from here

The 6600 CP had an 8-word instruction stack which functioned rather like an instruction cache, but without the flexibility of a modern cache. Program optimization consisted of allocating heavily used variables to registers, loading operands from memory a few instructions before they were needed, writing operands to memory a few instructions before their registers were needed to hold new operands, keeping several functional units busy simultaneously, and trying to get inner loops to fit into the instruction stack. The divide instruction was notorious, because it took about thirty clock cycles and its functional unit was not pipelined. The peak CP instruction rate was one instruction every 100 nanosecond clock cycle.

Of course, you can theoretically do better by doing it in the compiler than you can in the assembler, but you can easily get the first 80%.

If you bothered to read and understand the paper by Fluhrer, Mantin and Shamir that is linked to in the article you mention, you'd see that I know precisely what I'm talking about.

As the paper states:

Section 3 describes an interesting weakness of RC4 which results from the simplicity of its key scheduling algorithm. We recommend to neutralize this weakness by discarding the first N words of each generated stream.

And this paper was far from the first to note this weakness, although the authors did demonstrate a more effective method than had previously been known (which is what made it valuable research). The authors also presented a new and interesting weakness that can arise from one common approach to performing the key scheduling (XORins the IV with a fixed key, rather than hashing IV and key). Both points have an effect on WEP security. It's the two weaknesses when exploited together that lead to the "linear" time break of WEP.

However, as I said in the post you replied to: "it's a well-known fact that with RC4 you *must* discard the first few bytes of the keystream to permit the state table to be adequately mixed". Had the WEP protocol designers simply chosen to discard the first, say, 256 bytes of the RC4 keystream, the protocol would still be secure. The known-IV weakness might yet reveal another attack that could work even without the first few bytes of the keystream, which is why it is now recommended that a secure hash be used for mixing IV and key, but that attack has not been found as of yet.

My real point was not that RC4 was good enough (although it is). My real point was that clueless (yes, clueless, *everyone* knows you don't use RC4 that way!) designers misused it and created an insecure protocol. Now they're thinking that using AES will fix the problem. It won't. The problem was clueless designers, not a weak cipher. Giving the same clueless designers a new cipher will only give us yet another broken protocol.

Go Terps!

Here's the UMD Professor's 802.11 Research page

Come on now, when is the last time you wrote a data structure to store the primitive types of your language in a way that hasn't been done before?

You mean a completely new, genius-from-Mars, noone-ever-thought-of-that data structure? I haven't yet. I assert, however, that you need to know about all kinds of data structures. When you're building a system that's going to search hundreds of thousands (or more) of pieces of data, the difference between an O(log n) search tree and an O(n) linked list is often substantial -- seconds versus minutes. If you're actually stuck with that linked list, then a thorough knowledge of data structures will lead you to something like skip lists, which will let you get back a lot of the fast searching.

Programming is not about inventing new data structures, but you do need to know what's there, how it works, and (just as important) what it doesn't do well.

When is the last time you thought it necessary to analyze (algorithmically) code that you are writing?

Last week. The occasion before that was two weeks ago. Much of the code I write is for ideas so crazy noone has tried them before. Thinking about the algorithmic complexity of what I'm doing will make the difference between a program that runs overnight and one that takes a month and a half. That's just my own playpen... it's considerably worse for things like large weather simulations. There, algorithmic analysis is the difference between runtime of days or weeks versus years, or not being able to run a simulation at all.

Both of these are really the same point. Most programming is not about inventing radically new algorithms or data structures, just as most woodworking is not about revolutionizing the design of hammers, drills, and saws. Algorithms and data structures are tools, each with their own sets of strengths and weaknesses, and part of being a skilled craftsman is knowing which tool to use when.

I still like Finding the Speed of Light with Marshmallows

What's the practicality of this? Well, spiral MRIs, for example, where for mechanical reasons you don't want to have to stop-and-start the very heavy "scanner", wasting time and jarring sensitive equipment. As I said, niche applications.

As for compressing audio, there are already plenty of other psychoacoustic compression schemes -- whether non-uniform sampling is better or worse will likely depend on the application.

I remember reading this article way back when that talked about using Jimson weed to more efficiently store nuclear waste, water with plutonium in I think...

The gist of the story was that Jimson weed is supposed to be fairly hardy when exposed to nuclear waste. Feed the plant water with waste in it and the plant supposedly filters out and stores the waste material. The idea was to start with around 1000 barrels of liquid and end up with 1 barrel of radioactive Jimson weed. The end of the story was that this would all be a no-no because Jimson weed was a cousin to Marijuana- a controlled substance and so on.

I wonder- would doing this make the waste easier or harder to deal with? Wouldn't that barrel be much more radioactive? I know the total amount of radiation would be roughly the same, but it would be concentrated in a smaller volume. Ooh...critical mass maybe?

I tried to find the article online, but the closest thing was a reference in The Ultimate Resource II: People, Materials, and Environment.

Don't tell me how many things are wrong with the code, I just needed to visualize that thing scrolling!

Actually, I saw LotR not for the Lucas garb, but for the Legend of the Rangers trailer. Which I was in the wrong theatre for... :-\

Heres a page about the other LotR. :-)

One alternative is Ken Perlin's QuikWriting, which has been discussed on slashdot and covered by Wired.

"Quikwriting is significantly faster and less stressful to use than Graffiti, and lets you write very quickly without ever picking your stylus up off the surface, although it has the disadvantage that you need to learn a special alphabet. For further info, you can preview a Technote in either PDF or PostScript, which was published at the ACM UIST'98 conference."

Another alternative that builds on Perlin's QuikWriting work, is Francois Guimbretiere's and Terry Winograd's FlowMenus, published at UIST'00.

"We present a new kind of marking menu that was developed for use with a pen device on display surfaces such as large, high resolution, wall-mounted displays. It integrates capabilities of previously separate mechanisms such as marking menus and Quikwriting, and facilitates the entry of multiple commands. While using this menu, the pen never has to leave the active surface so that consecutive menu selections, data entry (text and parameters) and direct manipulation tasks can be integrated fluidly."

I'm currently designing and programming a user interface on the Palm for a remote control application. So I've implemented "Finger Pies", which are simply pie menus that you can use with your finger!

To paraphrase Ben Shneiderman: Finger Pies work well for implementing direct manipulation user interfaces on handheld personal touch screen devices, in which the application provides meaningful, engaging, tightly coupled feedback on the screen, in response to your gesture. By integrating immediate gratification over time, the user enjoys the satisfaction of direct engagement in an immersive experience, and achieves the cognitive resonance of continuous gratification. [My apologies to Ben for the tongue in cheek impression.]

Finger Pies are not meant to replace character input systems like Graffiti, but they are extremely useful and reliable for many applications of handheld input devices, because they're easy enough to use with your finger instead of a pen.

Finger pies are good for reliably selecting between two, four or eight options at a time (which can be nested as pop up submenus), and they're much more robust and resistant to noise than gesture recognition.

One problem with gesture recognition in general, is that it doesn't allow for "reselection" or in-flight refinement and error correction. That is, once you've made a mistake in a gesture, there's no way to change or cancel it, so you will often get characters that you don't mean, and you have to stop what you're doing and erase the mistake.

Pie menus allow you to cancel or change the selection at any time before you commit to the selection, so you can easily browse the menus. So pie menus are most appropriate when there aren't too many items, the items don't change dynamically over time, and when you need to minimize the error rate and selection time.

Most gesture recognition systems are not "self revealing" like pie menus, which can pop up a "map" showing the directions. So pie menus are much easier to learn than gesture recognition, and more appropriate for novice users. Best of all, they naturally train users to "mouse ahead" and select without looking, so they have a smooth, gentle learning curve.

Another advantage of pie menus is that they're not patented or restricted, and there are several freely available open source implementations.

-Don

Penny Lane: "This song was written about the roundabout in liverpool where John and Paul grew up. Half of the song is fact, half is fiction, but most of it is nostalgia. John was starting to write about personal places, and Paul really took this one and ran. "I wrote that the barber had photographs of every head he'd had the pleasure of knowing. Actually, he just had photos of different hair styles. But all the people do stop and say hello." say Paul. Also, "finger pie" is actually an old obscenity in Liverpool. The girls would never thnk of saying the word. It was used in the song as a fun joke for the lads back home. Months after, waitresses in Liverpool had to put up with lads asking for "fish and finger pie." There is also a phallic reference to the "fireman who keeps his fire engine clean." Penny Lane has become a Beatles landmark, and like Blue Jay Way, has it's problems with stolen signs, which are now nicely bolted down. Penny Lane was recorded on December 29, 1966 and released as a single with Strawberry Fields.The song also has a promotional video." -http://members.aol.com/Sumacca/songs.html

One alternative is Ken Perlin's QuikWriting, which has been discussed on slashdot and covered by Wired.

"Quikwriting is significantly faster and less stressful to use than Graffiti, and lets you write very quickly without ever picking your stylus up off the surface, although it has the disadvantage that you need to learn a special alphabet. For further info, you can preview a Technote in either PDF or PostScript, which was published at the ACM UIST'98 conference."

Another alternative that builds on Perlin's QuikWriting work, is Francois Guimbretiere's and Terry Winograd's FlowMenus, published at UIST'00.

"We present a new kind of marking menu that was developed for use with a pen device on display surfaces such as large, high resolution, wall-mounted displays. It integrates capabilities of previously separate mechanisms such as marking menus and Quikwriting, and facilitates the entry of multiple commands. While using this menu, the pen never has to leave the active surface so that consecutive menu selections, data entry (text and parameters) and direct manipulation tasks can be integrated fluidly."

I'm currently designing and programming a user interface on the Palm for a remote control application. So I've implemented "Finger Pies", which are simply pie menus that you can use with your finger!

To paraphrase Ben Shneiderman: Finger Pies work well for implementing direct manipulation user interfaces on handheld personal touch screen devices, in which the application provides meaningful, engaging, tightly coupled feedback on the screen, in response to your gesture. By integrating immediate gratification over time, the user enjoys the satisfaction of direct engagement in an immersive experience, and achieves the cognitive resonance of continuous gratification. [My apologies to Ben for the tongue in cheek impression.]

Finger Pies are not meant to replace character input systems like Graffiti, but they are extremely useful and reliable for many applications of handheld input devices, because they're easy enough to use with your finger instead of a pen.

Finger pies are good for reliably selecting between two, four or eight options at a time (which can be nested as pop up submenus), and they're much more robust and resistant to noise than gesture recognition.

One problem with gesture recognition in general, is that it doesn't allow for "reselection" or in-flight refinement and error correction. That is, once you've made a mistake in a gesture, there's no way to change or cancel it, so you will often get characters that you don't mean, and you have to stop what you're doing and erase the mistake.

Pie menus allow you to cancel or change the selection at any time before you commit to the selection, so you can easily browse the menus. So pie menus are most appropriate when there aren't too many items, the items don't change dynamically over time, and when you need to minimize the error rate and selection time.

Most gesture recognition systems are not "self revealing" like pie menus, which can pop up a "map" showing the directions. So pie menus are much easier to learn than gesture recognition, and more appropriate for novice users. Best of all, they naturally train users to "mouse ahead" and select without looking, so they have a smooth, gentle learning curve.

Another advantage of pie menus is that they're not patented or restricted, and there are several freely available open source implementations.

-Don

Penny Lane: "This song was written about the roundabout in liverpool where John and Paul grew up. Half of the song is fact, half is fiction, but most of it is nostalgia. John was starting to write about personal places, and Paul really took this one and ran. "I wrote that the barber had photographs of every head he'd had the pleasure of knowing. Actually, he just had photos of different hair styles. But all the people do stop and say hello." say Paul. Also, "finger pie" is actually an old obscenity in Liverpool. The girls would never thnk of saying the word. It was used in the song as a fun joke for the lads back home. Months after, waitresses in Liverpool had to put up with lads asking for "fish and finger pie." There is also a phallic reference to the "fireman who keeps his fire engine clean." Penny Lane has become a Beatles landmark, and like Blue Jay Way, has it's problems with stolen signs, which are now nicely bolted down. Penny Lane was recorded on December 29, 1966 and released as a single with Strawberry Fields.The song also has a promotional video." -http://members.aol.com/Sumacca/songs.html

It's not exactly carbon 14 dating; it's analysis of coral structures and related debris. Basically, it has to do with the rate of changes in coral structures over time, as well as sedimentation and things of that nature. Information about coral dating can be found here and here. Uranium/Thorium dating can be used on marine sediment (info here). Actually, the entire "Dating Exibit" site has a simplistic but good explanation of various relative and absolute dating techniques.

hmmmmm, I think there may be a mis calculation

According to the Impact Calculator, based on your initial parameters.

Projectile = Iron Asteroid
Diameter = 10.0 kilometer(s)
Velocity = 25.0 km/s
Target = Earth

Yeilds these results:

Energy Released = 305 million MT (MegaTons of TNT)
(The Dinosaur Killer: 100 million MT)
QUAKE!! Magnitude 11.3 (largest recorded Earthquake: 9.5)
Crater Diameter: 209.0 km
Crater Depth: 1.5 km
A collision this large occurs roughly once every 240 million years.

[insert picture of Marivin the Martian here]

http://janus.astro.umd.edu/gifdir/marvin.jpg

Ohh! Look at all the dust in Earth's atmosphere! It's going to block the sunlight and make it very very cold there for many years. There will be another wave of mass extinctions. You humans will not survive.

This actually was a big thing a few years ago. Thus you have goodies like the Sky and Telescope Impact Hazards website, along with this nifty cosmic impact calulator.

To be fair, there is this article about a scientist that thinks mass extinctions are a myth. ( I am skeptical of this.

And not that a ten mile wide asteroid would make a mess, but that an asteroid needed to wipe out and actually destroy the earth would likely be much much large, maybe 1,000 miles across or more.

10 miles across is like a bug on the windshield. Note that humans are living on the outside of the windshield.

So it sounds like you get to have fun researching impact craters on google, etc.

Close. Little Boy was the 2nd bomb -- Nagasaki, plutonium sphere. It needed shaped charges to compress the sphere to criticality.

Fat Man was the 1st bomb -- Hiroshima, uranium cylinders. It was an insanely simple design. The calculations can be done by any 3rd year nuclear engineering student.

You make a solid cylinder of enriched U235 whose mass is a smidge below critical. You also make a cylindrical shell of enriched U235, similar mass, whose inner radius is just big enough for the previous rod. When time comes, shoot the rod into the shell. Boom! 10 kilotons, every time (U235 bombs don't scale upwards much).

The only hard part is making bomb-grade U235, which requires a huge factory.

Two paradigms that actually are a bit more interesting aren't mentioned. The first is "active notebooks", as found in MathCad or Mathematica, related to a number of earlier toolkits like CLIM and DynamicWindows (now defunct), and also in some vague sense related to HTML/JavaScript/DOM. Such approaches combine text and documents with behavior and interaction. We might call them "document-based UIs" and they can be a lot easier to author, and they provide a lot more useful information and help to end users, compared to toolkits like Motif, Win32/MFC, Gtk+, and Qt.

The other interesting development is zoomable user interfaces, as in the Jazz toolkit. Zoomable user interfaces can be viewed as a very restricted form of 3D toolkit, something that is actually fairly easy to understand for users and reasonably consistent and straightforward to program for. Zoomable interfaces can also be viewed as the "structured graphics" document type complementing the document-based UIs I mentioned in the previous paragraphs.

If Linux or the open source community wants to break ground in delivering new, more usable, easy-to-author UIs, zoomable and document-based UIs are the way to go in my opinion. Hyperbolic browsers, 3D rooms, and time-ordered display are little frills around the edges.

There are several groups working on spintronics-related research around the globe. You can check some of the research the spin-doctors are working on by looking at the Spintronics 2001 Conference webpage. Some incredible results involved researchers injecting spin-polarized current into an LED and producing Circularly Polarized Light!!! Other researchers are trying to produced spin-transistors, to switch/amplify spin-polarized currents. Many of the recent challenges involve producing spin-polarized currents, finding materials that can transport electron-spin, and injecting spin-polarized electrons into semiconductors.

The Chien group here at JHU has been the first to demonstrate experimentally the existence of a half-metal. Crystals of CrO2 have been shown to have spin-polarization of 96%. This was measured at the superconductor/ferromagnetic interface through Point-Contact Andreev Reflection (PCAR) techniques.

I'll explain some of the current concepts of spintronics, but pardon any errors as I haven't really begun my research yet. The manipulation of electron spin is an extra degree of freedom that novel electronic devices can exploit. Spintronics has already, since 13 years after the discovery of GMR (Giant Magnetoresistance) in 1988, penetrated the technology industries (magnetic storage). It's rare for such new technology like this to be commercially available so soon after its discovery. Transistors were one such monumental achievement, the first Ge transistors were available within years of the transistor's invention.

GMR is an effect that occurs with a normal metal film that is sandwiched between two ferromagnetic layers. Depending on whether the spins of the ferromagnetic layer are parallel or anti-parallel, a significant change of resistance is measured across the structure. A more useful device which extrapolates off this concept is a spin-valve This is the standard GMR trilayer, with an anti-ferromagnetic layer on the bottom. This layer pins the spin of the bottom Ferromagnetic layer. The top ferromagnetic layer can then float, and have it's spin affected by the external magnetic field. This in turn creates a magnetic-field-dependent resistance across the device. Sensitive measurements of the magnetic field, obtained by measuring resistance, can be obtained in this manner .This magnetic-field-dependent resistance is known as Magnetoresistance. This concept, in a fundamental sense, is how the newer GMR-based read-heads on high-density hard drives operate.

Another similar device is the Magnetic Tunnel Junction . This is similar to the GMR trilayer, but an insulator film is sandwiched between the ferromagnetic layers, instead of a normal metal. Current can then tunnel through the device, again dependent on whether the spins are parallel or anti-parallel in the ferromagnetic layers. The tunnel junction is the fundamental concept at the core of the MRAM's.

Another exciting area of research with spintronics that I haven't heard anybody on slashdot mention yet is quantum computing. Electrons are spin-1/2 fermions, and hence have two distinct eigenstates of the Spin operator (the eigenstates are usually called "spin-up" and "spin-down"). This makes them perfect candidates for representation of quantum bits (qubits) for potential quantum computation. Some groups are working on this idea, by studying interactions of quantum dots for instance.

Overall, this is a budding field that has already impacted the technology industry in it's scant 13 years of existence. Expect many more interesting and potentially groundbreaking discoveries to occur. But then again, I'm spin-biased. :-)

An Intro to Spintronics - Univ. of Maryland

Article on Unisci about research into electronic spin in electronic devices

Fragile? Must be Italian!

As a co-inventor on US Patent# 5,331,222 (which has turned out to be basically worthless ;), I'd like to suggest to graduate students that they ask around as to whether a research advisor is proactive in getting students names on research papers, patents, etc., or whether they are not.

I've had the luck to work for two professors who were very pro-active about getting student names on papers and patents.

Jeez, 400 posts in an hour? I hope you find this one in the swarm...

I was in the same situation: University of Maryland, College Park. Three years into a CS degree, hating the classes, withdrawing left and right to avoid getting D's. I love computers, I love creatively using them, I hate to program. I loathe my classes, am not having any fun at school and generally was completely and utterly miserable.

Then I found the Independent Studies (IVSP) department, and I was saved! (insert church organ sting here)

Seriously. Works like this: You design your own cirriculum on a focused concept, drawing from courses across multiple disciplines. Get sponsored, get approval, go through an application process... and if it's clear you're serious about this and what you want to study isn't just 'Like Such-and-Such Major, But Easier' then you're in.

In my case, I designed (I still don't like the name, but..) Computers and Interactive Media. Lots of art classes and writing classes combined with computer science. Since I was able to mix and match and apply my humanities to my inhumanities, so to speak, I could study topics I was keen on -- user interface design, new methods of interactivity, product design, etc. I even tossed in some film study and computer graphics to implement multimedia in my work.

Now I'm a web designer and database programmer for the Food and Drug Administration's Center for Devices and Radiological Health. I have a stable job and I do a smorgaboard of tasks for my division; I redesigned the homepage, I streamlined various user data entry applications, and I retouched the chairman's photo to make him look less bald. Work is (usually) an entertaining challenge with a variety of things to do, rather than pumping out code 24/7.

If the CS department is not ringing your bell, if they aren't providing what you really want in life, see if there's an interdisciplinary studies or independent studies department on your campus. It can be a lot harder than a normal major in a lot of respects -- I was writing a five page paper a week at one point and the application process was crazy -- but it also might be exactly what you wanted.