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Slashback: Scramjet, Golden Ears, Preciousness
Everything that rises must come down under. spam-it-to-me-baby writes: "The Australian trial of a scramjet engine has fizzed. 'The experiment at the Department of Defence's Woomera Prohibited Area, 500 kilometres north of Adelaide, was not successful because the [United States-supplied] rocket experienced flight anomalies prior to the scramjet experiment,' an analysis of what went wrong says. Not to worry, another test is tentatively scheduled for next week, assuming researchers can work out what went wrong with this one on the way up."
Not to be confused with this previous scramjet test, also unsuccessful.
Ah, much better, I thought you were being unreasonable there for a minute. After Jamie drew attention to it in a Slashdot piece on Saturday, SafeSurf changed their legislative proposal. In Jamie's words, "Woo!"
That's not all he said, of course: "Please note that, now, they ONLY want to fine you thousands of dollars for failing to label anything you write that is harmful to an 8-year-old. What a relief! "The penalty for a first offense of failing to label or mislabeling material harmful to minors shall be limited to a fine of under five thousand dollars."
Bennett Haselton passed on this commentary as well:
"If you go to http://www.safesurf.com/online.htm in Netscape and "View Document Info", it shows it was last modified on October 29, 2001. (This function doesn't work in IE.)The original OCPA is [at google]. SafeSurf apparently removed this paragraph from section 6:
Publishers may be sued in civil court by any parent who feels their children were harmed by the data negligently published. The parents shall be given presumption in all cases and do not have to prove that the content actually produced harm to their child, only that the material was severe enough to reasonably be considered to have needed a rating label to protect children.and replaced it with:Publishers may be sued in civil court by any parent who feels their children were harmed by the data negligently published. The parents/plantiffs shall be given presumption, if the case involves graphic images, and do not have to prove that the content actually produced harm to their child, only that the material was severe enough to reasonably be considered to have needed a rating label to protect children.and then added three new paragraphs listing more exemptions from this rule."
Can you hear that pea through the mattresses? For the audio objectivists, a good update to CmdrTaco's recent MP3 v. Ogg Vorbis inquiry: E1ven writes: "Everyone is always arguing about whether Vorbis sounds better than MP3, or vice versa. Here is your chance to see who is right! ff123 is doing a set of Blind Listening tests and could use your help. The more ears the better!"
The National Coalition Against Censorship (NCAC) has an excellent paper which details exactly what "harmful to minors" means.
That's a pretty crappy test criteria-- limiting the input to 128kbit/sec-- for those of us itnerested in achieving as-close-to-CD-as-possible performance from our compressed music.
I don't claim to have golden ears, but I can distinctly hear the difference between different playback engines (example; on a Mac, the Audion playback engine is considerable better sounding than iTunes) and different encoding engines with nearly the same settings (LAME is, by far and away, the best I have heard yet).
In any case, it would be useful to have an expanded test that includes higher bitrates for those that listen to tunes on something other than crappy computer speakers.
Ogg vs. LAME article
An excellent Ars article that only covers differences between mp3 encoders.
MP3 tech has a bunch of useful resources.
One of the best sites around, r3mix offers a wealth of technical information, some very well executed scientific and listening tests, and a section that destroys a lot of the myths surrounding mp3s.
Innocent until proven guilty applies in criminal cases only. In civil cases, the default is "preponderance of the evidence" (i.e. more likely true or not). In many areas of civil law, though, the balance can be pre-tipped in this manner.
-Steve
Democracy is a poor substitute for liberty.
To my surprise, they responded later the same day:
OK, sounds good. I responded to Ray as follows (two days ago), but have not yet received a reply:
Make of this what you will. I still have not seen the "open and truthful" list of websites that Safesurf's software blocks.
Edith Keeler Must Die
While the audio test they're doing is good for "decent" audio, which is what Vorbis excels at, it's not a good test for what most of us are interested in - high (so-called "archival") quality audio compression. To do this testing LAME's -abr 134 vs. Vorbis's 128kbps is simply laughable; the current standards for LAME encoding are usually using either the "--r3mix" command line (as defined by www.r3mix.net) or the "--dm-preset standard" command-line. These typically average around 200-250kbps for rock music, and so far are indistinguishable from CD quality in the tests that have been done.
What would be interesting is if Vorbis can achieve these same results at lower bitrates; then I would agree it's better. If it can beat mp3 at 128kbps, then that's nice, but it's pretty irrelevant to me if it still sounds like crap (just not *as* crappy).
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
There is a control. Check out the files.
It's an odd one. Someone in the EU is trying to bring a law in makin it an offence to expose minors to pr0n. The problem being, in certain Scandinavian countries, it's part of the school curriculum to view and discuss pr0n. Bearing in mind that these countries have the lowest rates of "sex crimes", teenage pregnancies etc., that doesn't really point in the direction of "harm".
They do, however, have high suicide rates - this could either be to do with the lack of daylight in the winter, or kids realising that they're not hung like Ron Jeremey.
This sig made only from recycled ASCII
Just a general note on those scramjet tests. The guy in charge of these (Allan Paull) is my PhD supervisor, and I've been working in this area for about 4 years, though I'm not working on this project (I'm in Germany at the moment).
1. The tests were a failure in that supersonic combustion did not happen- That is, the engine operated as a ramjet rather than a scramjet. The first thought is that this was caused by the failure of the rocket turning manoeuvre, so that the air was entering the engine at a large angle from the main axis of the engine. Since the engine used has been tested up to 4 degrees of deviation, the angle was probably more than 4 degrees. The rocket needs to be turned so that it is facing downwards with the engine on the front. It should be able to do this due to the atmospheric pressure, but it turns out that it doesn't happen quickly enough. The rocket is a spin-stabilised type (Where the whole rocket spins, rather than have a separate gyroscope), and this means that the turning manoeuvre is a difficult problem in 3-D geometry.
2. Generally speaking, nobody (That I've heard of) in the scientific world is seriously looking at scramjets for a passenger plane. Amongst other thing, rockets have an unacceptable failure rate for general civilian flight.
3. The main proposal that I've heard is for a lifter of payloads in the one tonne range to near earth orbits. For that, scramjets should be cheaper than rockets. For the large payloads, rockets are still cheaper. There is a slight advantage with scramjets in that since most of the acceleration is done horizontally in the atmosphere, that a polar orbit is no more difficult to achieve than one on the equatorial plane.
4. In addition, though I'm sure there is research into scramjets for missiles (Of course it's not published in the open literature), there's not really a burning need to build faster missiles, since nobody is building faster planes or faster houses. Note also, that due to the air inlets, that a scramjet missile is inherently less stealthy than a rocket missile.
5. Somebody mentioned some tests in Russia. If these are the CIAM/NASA tests, then the papers I've read show all three flights operating primarily, in subsonic combustion mode. As ramjets.
6. One good reason for working in this field is because it is a discipline which brings together a lot of things that are also of use elsewhere. A lot of work is done on understanding the basic science, which feeds back into other areas. It's not really a field with a purely practical thrust at present, due to a continuing problem of not really understanding the aerodynamics at these speeds.
7. Thus the experiment which just failed was never really meant to be a working engine, but more a simplified example to use as a calibration for wind tunnels, and computer codes.
8. They used the terrier-orion rockets because Astrotech offered two of them for free. They have to get two tests under their belt before they can be generally licensed for testing in Australia. C/F new launch port at Christmas Island.
That's about all I can think of for the moment. The URL for the Hyshot project is:
http://www.mech.uq.edu.au/hyper/hyshot/