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IIRC the key to a naturally-looking ray-traced skin (or any natural material for that matter) is twofold -

* selecting a proper BRDF (bidirectional reflectance distribution function), which is very hard to get right even for a simple things like milk or paper

* accounting for a surface translucency, ie the fact that the ray hitting the surface not only gets reflected or diffused back into the air, but also partially absorbed by the surface itself. See here for details (sample renderings included).

Similarly to the what parent post said, both are very CPU-intensive problems, so you can go either with a brain-pleasing still picture of railgun bearer or an actual gameplay :) The choice is yours.

His latest project, Aaron, is the result of many years of experiment and refinement. The K++ project can draw abstract polygons. Aaron can draw portraits, landscapes, and still lives using perspective, detail, and composition.

You might want to look at Harold Cohen, the author of AARON. You might also be interested in a talk he did after retiring at the Tate (real format). I don't think that it's entirely clear whether the paintings are the work, or the program is the work.
AARON however, was capable of creating representation images, which requires AI work in of itself. I am not sure (without perusing the code) much K++ is intelligent.

This guy who does research on hard drive technology gives away a freeware Secure Erase HDDerase utility that just calls the HARDWARE-BASED Secure Erase capability that is ALREADY BUILT INTO all recent ATA-type hard drives!

We just need to figure out how to get Linux/*BSD/*NIX/Apple/Microsoft to make this an option at the OS or fdisk/format/Disk Utility/Volume Manager utility level so we can all use it easily.

This guy who does research on hard drive technology gives away a freeware Secure Erase HDDerase utility that just calls the HARDWARE-BASED Secure Erase capability that is ALREADY BUILT INTO all recent ATA-type hard drives!

We just need to figure out how to get Linux/*BSD/*NIX/Apple/Microsoft to make this an option at the OS or fdisk/format/Disk Utility/Volume Manager utility level so we can all use it easily.

Radiosity would dramatically increase the computational complexity.

Polygonal rendering: O(N), where n=number of triangles
Ray tracing: O(log N), where n=number of objects (assuming a good bounding volume heirarchy)
Photon mapping: O(P log max(P, N)), where P=number of photons, which generally must be inserted into a kd-tree, and N=number of objects
Radiosity: O(N^2), where n=number of triangles

Ray tracing could conceivably make a game faster, if the scenes are complicated enough. Radiosity, on the other hand, is very very slow. Photon mapping might be a better choice - it traces rays from the light source, and stores photons at the object intersection points, which are then used by the ray tracing step to approximate global illumination.

-jim

There are several 802.11 denial of service attacks explained in this paper

There are serious investigations into making cache optimized algorithms. For example, the matrix transposition and array index bit reversal algorithms have been investigated in two papers. Also, Bailey's 4-step and 6-step FFT algorithms are also cache efficient. The latter example shows that a complex algorithm such as a FFT can be made cache efficient with the sacrafice of only a few extra computations. Perhaps it would be prudent to use a hybrid ray-tracer/polynomial renderer to section each portion of the screen into regions that will only access a particular portion of memory. In fact, texture mapping is a lot like that. But I propose that we section the geometry into sections that are localized in memory. This will require more computation in the form of checking which ray goes where but it might be possible to create a viable ray tracer/polygon renderer that produces images of ray tracing caliber. By polygon renderer I mean the renderers that we currently use in gaming.

Some references about cache efficiency.

Forty years later, there's still no useful fusion power technology.

The US Department of Energy is terminating all work on fusion effective September 30, 2004. That's probably a good thing; it will free up activities in the EU and Japan from US interference.

assert() is part of the Standard C library. Please don't attribute it to MS VC++. They claim enough "innovation" as it is.

Might I note that this is the same Yoshi Kohno who broke the Diebold voting system and SSH.

Might I note that this is the same Yoshi Kohno who broke the Diebold voting system and SSH.

Might I note that this is the same Yoshi Kohno who broke the Diebold voting system and SSH.

If your audience was a bunch of morons you would say, "we must be nice to these people because they don't like our foreign policy."

If you're going to mention CSound (or FluidSynth), you should mention its complement (or uglier relative) PureData . PD is a Max/MSP clone, and one of the earlier programs to support JACK. By now, between PD, JACK, and ALSA's MIDI layer, you can basically do everything you can do in Max/MSP (OS9 and only recently OSX) under linux.

This is not to say that PD is necessarily a good introductory sound program -- after all, it is rather strange to right music using flowcharts.

The other I know of and think highly of that I didn't see is Bristol, a soft-synth.

This uses photon mapping for a lighting technique, which is inherently very good for lighting as it simulates ambient and reflected light as well.

Here are some global illumination pics from the person who developed this - global illumination - and for a nice video check out the top animation here.

Not sure if this will meet your satisfactions, but its closer than ever before.

This uses photon mapping for a lighting technique, which is inherently very good for lighting as it simulates ambient and reflected light as well.

Here are some global illumination pics from the person who developed this - global illumination - and for a nice video check out the top animation here.

Not sure if this will meet your satisfactions, but its closer than ever before.

Actually, this technique uses sub-surface scattering to accurately model the light transport characteristics of human skin.

Henrik has been a pioneer in developing efficient techniques for representing BSSRDF (bidirectional sub-surface scattering distribution functions).

This paper that he published in collaboration with other notable people at Stanford was among the first to describe methods of calculating the effects of sub-surface scattering.

This is also mentioned in his book, (2001), which I highly recommend to anyone interested in raytracing. It's short and about as easy to understand as photon mapping could possibly be.

He has a lot of stuff on his webpage, too, including videos of computer-generated smoke, light through translucent materials, and a good global illumination demo.

For a simpler explaination of what this is all about, there's a photon mapping entry at wikipedia.

-jim

This is also mentioned in his book, (2001), which I highly recommend to anyone interested in raytracing. It's short and about as easy to understand as photon mapping could possibly be.

He has a lot of stuff on his webpage, too, including videos of computer-generated smoke, light through translucent materials, and a good global illumination demo.

For a simpler explaination of what this is all about, there's a photon mapping entry at wikipedia.

-jim

Henrik Wann Jensen also got a technical Oscar earlier this year. This work is actually quite old. See the original Siggraph 2001 paper here.

There's 96 hits on Google [google.com] when you look up "Alper Coskun" (with quotes) and "98SE" -- none of which mentions his sinister plot to get your oh-so-valuable data that you keep on an ancient Windows 98 PC.

I cannot believe you people forgot M.U.L.E. For shame.

I write software that does similar things to this, except way more indepth than just a license plate scan.

So, because you wrote software similar to this means that it works the same way? You mean to say that this software -- which isn't *your* software -- doesn't necessarily do things beyond a lookup of the license plate string?

You've committed a logical fallacy of applying your anecdotal experience on one entity to an entire class of like entities.

Your description of the software is interesting an enlightening, but that's only what *you* worked on. There's plenty of other implementations out there.

The only people who have anything to fear are those that are trying to hide something.

EVERYBODY has something to hide. Publicly-gay men still get murdered for their homosexuality. Politically-active people still keep track of politically-active people. Identity theft is one of the fastest-growing crimes in America (a problem which can easily be exacerbated by criminally-minded people who run programs to monitor the public).

Moreover, just because something is a crime doesn't necessarily mean it *should* be. It's a crime in China to criticize the government, for instance, punishable by death. If they are tracked with your license plate scanner, should they have nothing to hide for exercising what *should* be a right to free speech?

And in the extremely-unlikely worst-case scenario -- that the U.S. has a second American Revolution to destroy our existing government, as Thomas Jefferson said it was the right and *duty* of the people to do if their government becomes too oppressive -- then software like yours only hinders the publics' ability to do that.

Your embrace of totalitarian monitoring is appalling. Move to Britain if you want 10 cameras on every man, woman, and child at all times. Truly patriotic Americans don't tolerate fascist communists like you.

Tell us your real name, address, phone number, email address, annual personal income, license plate number, and Social Security number if you have nothing to hide...

Just a little background so you know who's talking to who and why he knows what's going on =)

Not to be confused with The Turing Test, the Turin test has been long shrouded in controversy...

Another new focus: scientists. Here at UC San Diego, you see a lot of professors and researchers running around with PowerBooks, and not just in the art department. At the Scripps Institution of Oceanography, [ucsd.edu] almost everyone has a PowerBook. A bunch of the legacy scientific software has been ported to OS X and everyone loves that they can get work done and then give a lecture using the same computer. I wouldn't be surprised to see some of the old UNIX servers that they track weather and ocean currents on migrate to xServe.

There are graphical programming languages available, I know several people that gets serious work done in pd, particularly signal processing.

Different strokes for different problem domains, I guess.

Cryptanalysis of MD5 Compress.

Modern hash functions use a compression routine on buffered data to produce a hash. This compression function is performed repeatadly on - say 512 bit - blocks.

Dobbertin found a collision in the MD5 compression function. This is not the entire MD5 hash which includes padding and length added in the final compression.

MD5CRK is simply "the next step" from this paper.

You forgot to say IANAL.

Try the local college, Columbia etc. Usually the on campus bookstore sells laptops for a very good price, for example:
UCSD Bookstore
Of course San Diego is not New York but close enough?

The terrible secrt of space
IMAO this is a good anolog for what happends when you let people protect you from knowladge.

I only took a year's worth of physics (with one semester on electromagnetism), but this sounded very interesting so I went looking for more information. I stumbled upon a couple other articles that give a lot more information about the split ring structure, manufacturing technique, and scientific significance.

"In normal materials the constituent atoms and molecules determine electrical and magnetic properties; they are much smaller than the wavelength of light so only the average response of the atoms matters. In the new materials an intermediate or meta-structure is engineered on a scale somewhere between atomic dimensions and the wavelength of radiation. The properties of metamaterials are not limited by the periodic table and scientists can now engineer a huge range of electromagnetic responses that can be tailored to anything allowed by the laws of electromagnetism..."

The first design for a magnetic metamaterial was the 'Split Ring' structure. "A simple, plain ring of metal gives a magnetic response, but in the wrong direction....By cutting the ring the flow of current is interrupted by capacitance across the gap which, together with the inductance of the ring, makes a tuned circuit whose resonant frequency is determined by the inductance and capacitance. It is well known that a resonant structure responds with opposite signs on either side of the resonant frequency. Hence by tuning through the resonance the desired negative magnetic response is obtained: positive or negative."

The split ring structure "looks like a small letter 'C' inside a larger letter 'C', with the smaller C turned to face the opposite direction...many Split Rings brought together in organized 2D or 3D grids form a magnetic metamaterial." The material can be tuned for specific frequencies by changing the size and layout of the split rings. Here are metamaterials tuned to microwave frequencies, and the Terahertz materials used "a special 'photo-proliferated process' that deposited the 3 micrometer-wide (0.003 mm) copper rings on a quartz base."

Pretty cool stuff..."So far we have only seen negative refraction at microwave or GHz frequencies but some of the most exciting applications in sensing, communication, and data storage would be at higher frequencies... But the really valuable applications have yet to be dreamt of. Think back to when the first lasers were made, the reaction was that they were just incredible, but what the hell would we do with them?"

I only took a year's worth of physics (with one semester on electromagnetism), but this sounded very interesting so I went looking for more information. I stumbled upon a couple other articles that give a lot more information about the split ring structure, manufacturing technique, and scientific significance.

"In normal materials the constituent atoms and molecules determine electrical and magnetic properties; they are much smaller than the wavelength of light so only the average response of the atoms matters. In the new materials an intermediate or meta-structure is engineered on a scale somewhere between atomic dimensions and the wavelength of radiation. The properties of metamaterials are not limited by the periodic table and scientists can now engineer a huge range of electromagnetic responses that can be tailored to anything allowed by the laws of electromagnetism..."

The first design for a magnetic metamaterial was the 'Split Ring' structure. "A simple, plain ring of metal gives a magnetic response, but in the wrong direction....By cutting the ring the flow of current is interrupted by capacitance across the gap which, together with the inductance of the ring, makes a tuned circuit whose resonant frequency is determined by the inductance and capacitance. It is well known that a resonant structure responds with opposite signs on either side of the resonant frequency. Hence by tuning through the resonance the desired negative magnetic response is obtained: positive or negative."

The split ring structure "looks like a small letter 'C' inside a larger letter 'C', with the smaller C turned to face the opposite direction...many Split Rings brought together in organized 2D or 3D grids form a magnetic metamaterial." The material can be tuned for specific frequencies by changing the size and layout of the split rings. Here are metamaterials tuned to microwave frequencies, and the Terahertz materials used "a special 'photo-proliferated process' that deposited the 3 micrometer-wide (0.003 mm) copper rings on a quartz base."

Pretty cool stuff..."So far we have only seen negative refraction at microwave or GHz frequencies but some of the most exciting applications in sensing, communication, and data storage would be at higher frequencies... But the really valuable applications have yet to be dreamt of. Think back to when the first lasers were made, the reaction was that they were just incredible, but what the hell would we do with them?"

I only took a year's worth of physics (with one semester on electromagnetism), but this sounded very interesting so I went looking for more information. I stumbled upon a couple other articles that give a lot more information about the split ring structure, manufacturing technique, and scientific significance.

"In normal materials the constituent atoms and molecules determine electrical and magnetic properties; they are much smaller than the wavelength of light so only the average response of the atoms matters. In the new materials an intermediate or meta-structure is engineered on a scale somewhere between atomic dimensions and the wavelength of radiation. The properties of metamaterials are not limited by the periodic table and scientists can now engineer a huge range of electromagnetic responses that can be tailored to anything allowed by the laws of electromagnetism..."

The first design for a magnetic metamaterial was the 'Split Ring' structure. "A simple, plain ring of metal gives a magnetic response, but in the wrong direction....By cutting the ring the flow of current is interrupted by capacitance across the gap which, together with the inductance of the ring, makes a tuned circuit whose resonant frequency is determined by the inductance and capacitance. It is well known that a resonant structure responds with opposite signs on either side of the resonant frequency. Hence by tuning through the resonance the desired negative magnetic response is obtained: positive or negative."

The split ring structure "looks like a small letter 'C' inside a larger letter 'C', with the smaller C turned to face the opposite direction...many Split Rings brought together in organized 2D or 3D grids form a magnetic metamaterial." The material can be tuned for specific frequencies by changing the size and layout of the split rings. Here are metamaterials tuned to microwave frequencies, and the Terahertz materials used "a special 'photo-proliferated process' that deposited the 3 micrometer-wide (0.003 mm) copper rings on a quartz base."

Pretty cool stuff..."So far we have only seen negative refraction at microwave or GHz frequencies but some of the most exciting applications in sensing, communication, and data storage would be at higher frequencies... But the really valuable applications have yet to be dreamt of. Think back to when the first lasers were made, the reaction was that they were just incredible, but what the hell would we do with them?"

I only took a year's worth of physics (with one semester on electromagnetism), but this sounded very interesting so I went looking for more information. I stumbled upon a couple other articles that give a lot more information about the split ring structure, manufacturing technique, and scientific significance.

"In normal materials the constituent atoms and molecules determine electrical and magnetic properties; they are much smaller than the wavelength of light so only the average response of the atoms matters. In the new materials an intermediate or meta-structure is engineered on a scale somewhere between atomic dimensions and the wavelength of radiation. The properties of metamaterials are not limited by the periodic table and scientists can now engineer a huge range of electromagnetic responses that can be tailored to anything allowed by the laws of electromagnetism..."

The first design for a magnetic metamaterial was the 'Split Ring' structure. "A simple, plain ring of metal gives a magnetic response, but in the wrong direction....By cutting the ring the flow of current is interrupted by capacitance across the gap which, together with the inductance of the ring, makes a tuned circuit whose resonant frequency is determined by the inductance and capacitance. It is well known that a resonant structure responds with opposite signs on either side of the resonant frequency. Hence by tuning through the resonance the desired negative magnetic response is obtained: positive or negative."

The split ring structure "looks like a small letter 'C' inside a larger letter 'C', with the smaller C turned to face the opposite direction...many Split Rings brought together in organized 2D or 3D grids form a magnetic metamaterial." The material can be tuned for specific frequencies by changing the size and layout of the split rings. Here are metamaterials tuned to microwave frequencies, and the Terahertz materials used "a special 'photo-proliferated process' that deposited the 3 micrometer-wide (0.003 mm) copper rings on a quartz base."

Pretty cool stuff..."So far we have only seen negative refraction at microwave or GHz frequencies but some of the most exciting applications in sensing, communication, and data storage would be at higher frequencies... But the really valuable applications have yet to be dreamt of. Think back to when the first lasers were made, the reaction was that they were just incredible, but what the hell would we do with them?"

Anyone know if the new guy is Linux-friendly?

I know Dell claims to be, and pretended to try Linux on consumer systems and gave up claiming "they weren't selling"... but that was because of the systems they chose to list Linux as an option with.

Just because we like an OS that _happens_ to be free (in both senses of the word), doesn't mean we're cheapskates!

How many Linux users do you know who would go out and buy the bottom-of-the-line of anything?
We go for the hotrods, bigger/better/faster/more.
I don't care if that monster notebook weighs 8.5#, I'm not a wimp, I want the power and rediculously-high resolution screen!

Actually - after reading an article on installing Linux on an I8600, I priced one - amazing how cheap you can get a 1920x1200 LCD notebook for these days.

Too bad it requires the MS-tax.

The 1st thing I'd do with it is shrink down the MS partition to as small as it goes (to keep it around to make the diag-drones happy) and install Linux on it. (just like I did with the notebook I'm typing this on, sadly only having 1400x1050 on the LCD).

You need some mechanism to "increase" the apparent area of the (in this case KBO.) Unfortunately, KBOs are just small rocks, with not too much interesting going on. (Planets that eclipse their own star are easier to see, because they are fixed in the angle they explore on the sky relative to the star.)

If you're looking for some kind of "eclipse" effect on the background stars, the best way to increase the effective area of your object is to make it heavy enough that it can gravitationally lens something behind it. The lensing effect increases the angular size of the "sweet spot." See the various MACHO searches.

Not necessarily.

In order to the ice melt, temperature must be increased. A hotter liquid can hold less dissolved gasses. An increase of one degree C on the oceans means some billions of tons of CO2 more on the air.

And we simply dump too much CO2. "The average American per capita emission is 5 tons of carbon annually."> (Damn! It's TOO much!)

More CO2 on the air, plus oceans retaining less C02 means something bad will happen.

Henrik Wann Jensen (one of the winners) is a professor at UCSD. He has had numerous contributions to the area of Computer Graphics, including Photon Maps, Subsurface Scatterring, etc. Some of the animations and images of of his work are trully amazing.

Henrik Wann Jensen (one of the winners) is a professor at UCSD. He has had numerous contributions to the area of Computer Graphics, including Photon Maps, Subsurface Scatterring, etc. Some of the animations and images of of his work are trully amazing.

Henrik Wann Jensen (one of the winners) is a professor at UCSD. He has had numerous contributions to the area of Computer Graphics, including Photon Maps, Subsurface Scatterring, etc. Some of the animations and images of of his work are trully amazing.

And two words for you:

Irreducible Complexity

Time to start using trigraphs then?

they rely on known calculations that are extremely difficult (astronomically computationally expensive) to run backwards

Not quite. They're believed to be extremely difficult to run backwards. And there are some subtleties beyond that... read "A Personal View of Average-Case Complexity" from Russell Impagliazzo's page.

If you're a max fan Pure Data may be worth a look. Similar concepts and open-source.

True home page is here

very favorably?

The orbiter can transmit data at over 80,000 bits per second for 16 hours per day. That maxes out to 576 MB per day.

It takes 118 minutes for the orbitor to circle Mars. From the description you linked to, I interpret the orbiter to be in communication range for eight minutes per revolution. At 12 revolutions per day, that's 87 MB per day. Over a 90 day mission, we could get almost 8 GB of data.

• For me, making the telescope was all about the experience of learning & having a project -- not saving money. I believe I could've bought a better telescope for less money than I spent on making mine (not including the cost of time spent).
• The plans are quite good and complete -- though I still had to improvise quite a bit when I didn't have exactly the same materials. However, improvising turned out to be some of the most fun, since it was problem-solving.
• On a more technical note, one of my improvisations forced me to place the secondary mirror closer to the main mirror than it really should have been, therefore I lost about 3/4" of the main mirror. This is something to be aware of. This was mostly due to my naivete, and the plans don't really mention this issue. When placing the secondary mirror, take time to really consider your main mirror, focal length, and *the size of your secondary mirror*.
• The mirror collimation design (3 bolts on a board) works really well, I think, for how simple the design is.
• I bought my mirrors from E-scopes, and was happy with them. I bought teflon from Rob Teeter at Teeter's Telescopes, and I recommend them.
• The tube can be had from a local construction surplus store -- it's called Sonotube (brand name) in the industry, and it's used to pour concrete pillars. I was afraid that 1/8"-thick would be too thin, and I considered going with 1/4", but 1/8" turned out to be fine (and much lighter).
• I'm extremely happy with my telescope, and while it isn't perfect, I had so much fun making it, and it's so easy to use. I had no sooner finished it than I wanted to make a larger one. :)
• Here are 6 pictures taken of the moon with this telescope (just holding my camera up to the eyepiece with my hand): 1 2 3 4 5 6

Good luck, and have fun!