Slashdot Mirror

This is starting to shit me - I'm all for shameless self-promotion but goddammit make sure you've got a server that will last more than 10 seconds!

Can I also please make the Ob/. joke that the page is clearly being hosted on the pokemon-mini they've hacked?

Can you point me to a good summary of the status of Linux on iPAQ? WiFi support, all that? I'm drooling over a Linux PDA, but iPAQ hardware is more available - and I'll be damned if I use WinCE under any circumstances.

I am an embedded linux developer, so am not afraid of hacking, just want a decent base to work from. Have one kernel port up my sleeve, not ready to start another one yet! :-)

Travelling to USA in just over a week will be a good opportunity to pick up a good Linux-capable iPAQ at a fraction of the cost buying it here in Oz.

Thanks,

No article on Nanobacteria would be complete without a reference to Philla Uwins. A geologist who in 1999 was inspecting (deep, hot and old) drilling samples from the Western Australian coastline with a scanning electron microscope discovered unusual possible life forms from 20nm to 150nm, christening them nanobes. Well below the accepted 200nm miniumum thought possible for life. (it is thought that no living thing can contain the necessary machinary in containers below 200nm).

What followed is probably more interesting than this reported story (the discovery of nanobes in blood and their possible link to disease predates this article). Things started to hot up in the nanobe world when some research money came forward to see if these nanobes contained the necessary DNA to disprove the many *non life advocates*. Even physicist Paul Davies (Australian centre for Astrobiology) pondered the possibility that nanobes could be a possible link between life and non-life.

Armed with some results the Unwin team sent off a paper to every *major* reputable scientific journal only to have them turned down. The most common reason.... too controversial.

So I read this story and think of *mayo* clinic and the *ohhh must be reputable* tag that goes with it and thinking why hasn't Nature or some other journal taken so long to publish these ideas?. Science publishing appears to be more about convincing publishers (and peers) less about looking at the data.

The postscript to the story: The dot com crash in 2000 killed off more research into the DNA tests, the possible application of the nanobes into eating plastic (nanobes had a voracious appetite for petri dishes) and a potential commercial spin off. Phillipa still works at UQ.

• 
  assorted links
  
  http://www.uq.edu.au/nanoworld/uwins.html
  
  http://aca.mq.edu.au/PaulDavies/pdavies.html
  
  http://www.abc.net.au/science/news/stories/s2015 6. htm
  
  http://www.abc.net.au/rn/science/ss/stories/s132 23 5.htm
  
  http://www.guardian.co.uk/Archive/Article/0,4273 ,3 840998,00.html
  
  

No article on Nanobacteria would be complete without a reference to Philla Uwins. A geologist who in 1999 was inspecting (deep, hot and old) drilling samples from the Western Australian coastline with a scanning electron microscope discovered unusual possible life forms from 20nm to 150nm, christening them nanobes. Well below the accepted 200nm miniumum thought possible for life. (it is thought that no living thing can contain the necessary machinary in containers below 200nm).

What followed is probably more interesting than this reported story (the discovery of nanobes in blood and their possible link to disease predates this article). Things started to hot up in the nanobe world when some research money came forward to see if these nanobes contained the necessary DNA to disprove the many *non life advocates*. Even physicist Paul Davies (Australian centre for Astrobiology) pondered the possibility that nanobes could be a possible link between life and non-life.

Armed with some results the Unwin team sent off a paper to every *major* reputable scientific journal only to have them turned down. The most common reason.... too controversial.

So I read this story and think of *mayo* clinic and the *ohhh must be reputable* tag that goes with it and thinking why hasn't Nature or some other journal taken so long to publish these ideas?. Science publishing appears to be more about convincing publishers (and peers) less about looking at the data.

The postscript to the story: The dot com crash in 2000 killed off more research into the DNA tests, the possible application of the nanobes into eating plastic (nanobes had a voracious appetite for petri dishes) and a potential commercial spin off. Phillipa still works at UQ.

• 
  assorted links
  
  http://www.uq.edu.au/nanoworld/uwins.html
  
  http://aca.mq.edu.au/PaulDavies/pdavies.html
  
  http://www.abc.net.au/science/news/stories/s2015 6. htm
  
  http://www.abc.net.au/rn/science/ss/stories/s132 23 5.htm
  
  http://www.guardian.co.uk/Archive/Article/0,4273 ,3 840998,00.html
  
  

Dr. Phillipa Uwins, an electron microscopist from Queensland Australia found nanobes less than 100 nanometres big when analysing core samples returned from petrochemical exploration.

1999 Discovery

Interview on Robin Cook's Science Show.

The MMU is also a power and size liability. Spending money on engineering a resource-light product can be worth it, especially when confronting the rising ubiquity of mobile client devices, in a PAN.

Right now I'm tracking a uCLinux port to the MicroBlaze "soft processor", which runs on the Xilinx FPGAs. There's no MMU because gates are precious in the reconfigurable HW. They're having timing problems, where the simulated clock drifts, often wildly and hugely, in a feedback with certain performance scenarios. But they can factor out high-profile kernel and app source code into hardware, like the TCP/IP stack. That gets back performance and determinance. And retains flexibility in the field, for adaptive runtime porting features to HW in the remaining gates. I'm interested in learning more about the limits of uCLinux (vs. the standard kernel) for designing apps to port to that platform.

But anyway, I do this for a living, and my first bit of fun was to port the Linux kernel to run on an FPGA-based processor, the Xilinx Microblaze.

Next step, work I'm doing at the moment, is to map the reconfiguration memory into the Linux device heiracrchy, so I build self-reconfiguring Linux systems. Imagine Arnie in T2 operating on himself, and you're getting the idea.

Doing it this way, I can type something like

cat bitstream.bit > /dev/self

and it causes the fpga-based linux system to partially reconfigure the FPGA itself, swapping in new hardware functionality.

fun stuff..

Making these cars more expensive doesn't make them more disposable. It makes their mechanics more valuable. Like in Stephenson's _Snow Crash_, we might just wake up as a nation of mechanics (and 1337 pizza delivery). Different subsystems in the cars interacting in diagnosable and tweakable configs means work for humans diagnosing and configuring. And when the logic, sensors and actuators are all field programmable, American cars might be the platform in which parallel processing, dataflow, evolved realtime optimizations.

ipodLinux is based on uClinux, which is a version of Linux that runs on processors without an MMU (Memory Management Unit).

The research group where I work is quite involved in embedded linux work. Last year I ported the Linux kernel to an FPGA-based processor called Microblaze. I'm now doing all sorts of fun stuff involving dynamically self-modifying hardware and other bizarro stuff. All good fun.

uClinux is running in something like 20 million devices, ranging from DVD players to netowrking routers and embedded VPN servers.

Give it a couple of years, and the embedded linux market will make the desktop look puny. The talk on slashdot is all about the Linux desktop, but Linux is already winning the real war, embedded systems.

ipodLinux is based on uClinux, which is a version of Linux that runs on processors without an MMU (Memory Management Unit).

The research group where I work is quite involved in embedded linux work. Last year I ported the Linux kernel to an FPGA-based processor called Microblaze. I'm now doing all sorts of fun stuff involving dynamically self-modifying hardware and other bizarro stuff. All good fun.

uClinux is running in something like 20 million devices, ranging from DVD players to netowrking routers and embedded VPN servers.

Give it a couple of years, and the embedded linux market will make the desktop look puny. The talk on slashdot is all about the Linux desktop, but Linux is already winning the real war, embedded systems.

http://www.mech.uq.edu.au/hyper/hyshot/:
As the spent motor and its attached payload falls back to Earth, they gather speed, and the trajectory is designed so that between 35km and 23km, they are travelling at Mach 7.6

http://www.uq.edu.au/news/index.phtml?article=3469 :
The recent HyShot(TM) launch was designed to take the scramjet engine to a speed of Mach 7.6 (or more than seven times the speed of sound) for the experiment, using a Terrier Orion rocket. The rocket and payload reached an altitude of 314km before the rocket was configured to fly in a new trajectory pointing the payload back down to earth.

HyShot was simply free-falling to earth in order to reach Mach 7.6 so the engine could be ignited. It achieved that speed regardless of whether or not the scramjet fired. The X-43 was flying horizontally, and was actually powered by the scramjet engine during a controlled flight.

So there is a difference between what was accomplished. The distinction is that HyShot achieved combustion, while the X-43 was the first scramjet powered craft to be flown.

Dan East

http://www.mech.uq.edu.au/hyper/hyshot/:
As the spent motor and its attached payload falls back to Earth, they gather speed, and the trajectory is designed so that between 35km and 23km, they are travelling at Mach 7.6

http://www.uq.edu.au/news/index.phtml?article=3469 :
The recent HyShot(TM) launch was designed to take the scramjet engine to a speed of Mach 7.6 (or more than seven times the speed of sound) for the experiment, using a Terrier Orion rocket. The rocket and payload reached an altitude of 314km before the rocket was configured to fly in a new trajectory pointing the payload back down to earth.

HyShot was simply free-falling to earth in order to reach Mach 7.6 so the engine could be ignited. It achieved that speed regardless of whether or not the scramjet fired. The X-43 was flying horizontally, and was actually powered by the scramjet engine during a controlled flight.

So there is a difference between what was accomplished. The distinction is that HyShot achieved combustion, while the X-43 was the first scramjet powered craft to be flown.

Dan East

I don't know if there is an independant peer review of their data but from their web site University of Queensland Hyshot Program Nasa's own press release doesn't say that they broke any records.... Either way Kudos to NASA....maybe now we'll get cheaper access to space

There's one fundamental difference between an ordinary jet engine and a scram jet engine: The Ramjet has no moving parts.

The all jet engines,operate according to Newton's Third Law of Motion:
For every action, there's an equal opposite reaction

The standard jet engine, invented by Sir Frank Whittle, sucks in air at the front. Then this air is mixed with fuel, and made to combust. The combustion causes the air to exit the engine at a velocity greater than when it came in, thus creating thrust. The escaping air causes the turbine to spin, and this intern activates the compressor, sucking more air in.

The Ramjet has no turbine and compressor unit. Ramjets fly supersonically and have an inlet which injests subsonic air after it goes through a shock wave in front of the inlet. The intake is slowed down aerodynamically, and then mixed with fuel and made to combust. But after about Mach 5, ramjets don't work so well.

The scramjet is almost but not quite entirely like a ramjet. The only difference being in a scramjet the combustion takes place as the air is travelling through the chamber at supersonic velocities.

More about the scram jet. Or another more concise explanation.

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Yeah, it's Hyshot

However, let's not forget that Hyshot's flight path was toward earth. Also the scramjet worked in the last few seconds before it crashed into the earth. NASA's test was a horizontal flight high in the atmosphere.

No, they just don't like it when a project that cost a fraction (arround AU$1.5 million) of what theirs did suceeded before theirs did, by a bunch of mechanical engineers at a university that nobody knows about. More details about the project are available at the Center for Hypersonics and UQ news.

We had some lectures from the head of the engineering faculty in first year, and he went into a fair bit of detail on how the system worked. Last I heard was that the project has received further funding, but that was shortly after their mostly sucessful trial run (they couldn't find their rocket for a few weeks in the Australian desert). I've heard nothing else about it since, though. But that's probably because all anybody talks about now is mice in space.

No, they just don't like it when a project that cost a fraction (arround AU$1.5 million) of what theirs did suceeded before theirs did, by a bunch of mechanical engineers at a university that nobody knows about. More details about the project are available at the Center for Hypersonics and UQ news.

We had some lectures from the head of the engineering faculty in first year, and he went into a fair bit of detail on how the system worked. Last I heard was that the project has received further funding, but that was shortly after their mostly sucessful trial run (they couldn't find their rocket for a few weeks in the Australian desert). I've heard nothing else about it since, though. But that's probably because all anybody talks about now is mice in space.

No, they just don't like it when a project that cost a fraction (arround AU$1.5 million) of what theirs did suceeded before theirs did, by a bunch of mechanical engineers at a university that nobody knows about. More details about the project are available at the Center for Hypersonics and UQ news.

We had some lectures from the head of the engineering faculty in first year, and he went into a fair bit of detail on how the system worked. Last I heard was that the project has received further funding, but that was shortly after their mostly sucessful trial run (they couldn't find their rocket for a few weeks in the Australian desert). I've heard nothing else about it since, though. But that's probably because all anybody talks about now is mice in space.

The first Professor of Physics at the University of Queensland, Professor Thomas Parnell, began an experiment in 1927 to illustrate that everyday materials can exhibit quite surprising properties. The experiment demonstrates the fluidity and high viscosity of pitch, a derivative of tar once used for waterproofing boats. At room temperature pitch feels solid - even brittle - and can easily be shattered with a blow from a hammer. It's quite amazing then, to see that pitch at room temperature is actually fluid!

In 1927 Professor Parnell heated a sample of pitch and poured it into glass funnel with a sealed stem. Three years were allowed for the pitch to settle, and in 1930 the sealed stem was cut. From that date on the pitch has slowly dripped out of the funnel - so slowly that now, 72 years later [1998], the eighth drop is only just about to fall.

You don't need to be a superpower to experiment in this area. The University of Queensland here in Oz has the HyShot program which, despite a few teething problems, is producing world class results. The US has yet to see any results from its X-43 series. It will be interesting to see if India can live up to its own hype. Good luck to them.

No I'm a molecular biologist I mean 80% by volume (160 proof) anything much less won't precipitate the DNA. I'm in the UK and can buy 80% vodka from my local supermarket. (I plan to buy a bottle and use it when doing demos for the university open day .... granted I'll empty the bottle and use the lab ethanol, but the appearance that counts.)

A little Googling gives me a 160 proof spirit Polmos Polish Pure Spirit (about half way down the page). Technically it may not be a vodka, in my travels I read the a vodka has to be between 80 and 110 by proof (OTOH my brain cells will probably not make the distinction:-). I also came across references that booze above 140 proof was illegal to sell in the US

The bridge survives!!

Too bad about the crew quarters where all the red-shirts had been having tea.

Slashdot has a page where they put the University of Queensland Laser Diagnostics Dept Webserver through the gauntlet in a mach 5 slashdotting. It held up as expected."

This is a people issue. Make and use a process that is described clearly and mentioned often. Inform everyone of misconduct cases.

Our numbers are going down.

Ralf

Well, they're begging the question somewhat, but it seems true that globular clusters metal deficient. Jupiter's atmosphere is 82% hydrogen, 14% helium and only a trace of heavier elements. Who knows what goes on at the core, but that would seem to indicate that planets don't need rock to form.

That said, if we found some moons around it somehow at some point in the future, there would be a lot of questions that need answering.

Is it worrying anyone else, though, how thoroughly we're cutting in to the upper estimate of the age of the universe according to Big Bang Theory? Prior guesses on the age of the universe in BBT were in the 9-12 billion range.

Invoking tweaks on inflation theory and 'anti-gravity' via the cosmological constant, the upper limit has been moved up to 15 billion years. Now here we are with a planet... a close planet (all things considered, 7200 light years isn't that far away on a grand scale :), that's 13 billion years old plus star and cluster formation time, and some of the other observations from the furthest visible reaches coming back from ye olde Hubble... how much further can we cut into this without jeopardizing the 15 billion year estimate?

Something to consider...

Everyone computer scientist knows about the No Free Lunch Theorem, so be leery!

With regards the original article - well, that was a bunch of obvious guff really; what you'd expect from high-school geeks of the type I was, some number of years ago. Of note, is that it claimed to decompile C++, when actually it talked only of rather trivial C constructs, something that is a well understood practice already.

Some relatively recent classic decompilation work was done by Cristina Cifuentes who put together a C decompiler that worked to a significant degree for common DOS-based compilers of the time. Effectively the job of "decompilation" can be thought of as "compilation" - instead of compiling C into ASM, you think of compiling ASM into C. Not as daft as it sounds, honest. You can download "dcc" from the above site to investigate further.

Boomerang is a sourceforge project attempting to create a decompiler. Worth a look, as well.

It's worth noting, that there are a number of ways to "cheat". For example, it's often trivial to discover what compiler was used to generate a given object code, and there are usually masses of common library-type code that gives you a leg up. Add to that, the fact that a piece of code was generated by a compiler, and the problem of discovering what a given piece of object code does is drastically simplified - compilers add huge amounts of structure and predictability to the generated object code that can be absent in free-form handwritten assembler (and few people do that anymore!), and much can be made of this.

On the code/data issue mentioned by others in this thread - although separating code/data in general from mixed binaries can be considered hard, in reality it's often quite feasible and even simple. After all, the CPU manages to work it out. Again, the fact that there are so many short-cuts you can take really helps.

Of course, a quick cruise around the cracking community will turn up all sorts of ways and means to shortcut this sort of problem...

Here are the results of a quick googling:

• Univac 494 to 1100 Series Decompiler
• REC Decompiler
• DisC - Decompiler for TurboC

With regards the original article - well, that was a bunch of obvious guff really; what you'd expect from high-school geeks of the type I was, some number of years ago. Of note, is that it claimed to decompile C++, when actually it talked only of rather trivial C constructs, something that is a well understood practice already.

Some relatively recent classic decompilation work was done by Cristina Cifuentes who put together a C decompiler that worked to a significant degree for common DOS-based compilers of the time. Effectively the job of "decompilation" can be thought of as "compilation" - instead of compiling C into ASM, you think of compiling ASM into C. Not as daft as it sounds, honest. You can download "dcc" from the above site to investigate further.

Boomerang is a sourceforge project attempting to create a decompiler. Worth a look, as well.

It's worth noting, that there are a number of ways to "cheat". For example, it's often trivial to discover what compiler was used to generate a given object code, and there are usually masses of common library-type code that gives you a leg up. Add to that, the fact that a piece of code was generated by a compiler, and the problem of discovering what a given piece of object code does is drastically simplified - compilers add huge amounts of structure and predictability to the generated object code that can be absent in free-form handwritten assembler (and few people do that anymore!), and much can be made of this.

On the code/data issue mentioned by others in this thread - although separating code/data in general from mixed binaries can be considered hard, in reality it's often quite feasible and even simple. After all, the CPU manages to work it out. Again, the fact that there are so many short-cuts you can take really helps.

Of course, a quick cruise around the cracking community will turn up all sorts of ways and means to shortcut this sort of problem...

Here are the results of a quick googling:

• Univac 494 to 1100 Series Decompiler
• REC Decompiler
• DisC - Decompiler for TurboC

The first successful testflight of a scramjet engine occurred at the Woomera rocket range in Australia in 2002. project homepage

It will be a long time (maybe never?) before this becomes a viable technology for a space shuttle though. Even the more immediate goal, of a cheap launcher for small satellites, is decades away. NASA were completely correct to discount it.

The first successful testflight of a scramjet engine occurred at the Woomera rocket range in Australia in 2002. project homepage

It will be a long time (maybe never?) before this becomes a viable technology for a space shuttle though. Even the more immediate goal, of a cheap launcher for small satellites, is decades away. NASA were completely correct to discount it.

already been done.

http://www.physics.uq.edu.au/gqc/

Don't tell Stallman.

April fools aside seems like this really happens.

The current, voltage, motor speed (and torque), and AC frequency are all interrelated. Here is some good information on the web.

http://www.valhallascientific.com/applications/app lications-3.shtml

http://www.lehmanengineering.com/quiz/quiz6sol.htm l

http://www.mech.uq.edu.au/courses/mech3760/chap34/ s1.htm

Humans create "reactive load" by running motors. Motors draw current, increase in current lowers voltage amplitude across a transmission line, plus larger power flow causes increase in reactive loss on a power line. Reactive loss lowers the voltage at both the supply end and the delivery end. Lower voltages reduces the torque in the motor shaft, not to mention reactive demand reduces the real output of the generator. This tends to slow down the motor, and the rotor speed is proportional to the frequency, so the overall frequency drops.

The only difference is that there is no cat. Err, I mean, the whole concept of "reactive" energy is just a mathematical construct representing amplitudes and phase angles. Its the old A<Phi vs R+jX conversions. But they're messy.

Don't sell your country short, friend. Those fellows at University of Queensland have as much or more expertise flying scramjets as anybody else in the world.

Me, I'm an aerospace engineer who's a lot more interested in the aero part than the space part. Maybe when we both get jobs, we can trade. : )

I think the ISS is cool for its gee-whiz factor, but I've come to view it as a) too expensive for what it does and b) not useful to get us to Mars, which I believe should be our A-1 short term goal. The book that crystallized my thinking on this is called The Case for Mars, and I never let a discussion about space travel go by without harping on how really really clever this plan is.

NASA has stated that ISS is necessary for, and will be used for, space exploration. I just no longer believe them. It's not necessary to get us to Mars, and I believe it's soaking up the funding that WOULD get us there. That, in a nutshell, is why I don't support the ISS program.

I've got to disagree with your post.

While it is true that it was published by Cambridge Press, you missed out that it was published by their Social Sciences division. This is a big problem if one wants to treat it as a scientific work. If you wanted to find out about physics, which would be a more authoritive work, a physics book out of the CP science division, or a book of feminist intrepetations of physics out of the CP social sciences division? If your going with the first option, why not apply the same rules to Lomborgs work?

As for stating "he's a statistician, not an earth scientist, so he takes for granted the numbers already being used in the field, and applies statistical analysis to them", the problem that I'm trying to point out is that by biased selection of "the numbers already being used in the field", he can get whatever result that he likes. For example, on his section of global warming he uses the modelling of William Nordhaus, while ignoring many of the well documented theoretical shortcomings of his models. (Source). This isn't science.

An interesting review of Lomborg's work on enviromental economics, can be found here. The author's make my above point a little bit more aggressively; "Statistician Lomborg blatantly distorts the evidence by systematically selecting statistics to support his claims that global welfare is generally improving and environmental policy is unnecessary, while denying catastrophic risks such as prolonged drought in major food growing areas (though such events cannot be ruled out by climate models). "

I wouldn't necessarily call those questioning him the height of the field either -- as the Economist was quick to point out, those objecting to his work are mostly the same crowd of doubtful prognosticians who brought us global cooling theory right up through the mid-eighties, before jumping on the global warming bandwagon.

That's a very broad brush your using. Can you find any link between global cooling and any of the three author's I've cited in this post (Felix FitzRoy, Ian Smith and John Quiggin)?

Anyway, all of the reviewers who you have tarred (Schnider (sp?) and co) have far more peer reviewed papers than Lomborg (who I just checked on the Current Contents database, and has the grand total of 1 (published almost 7 years ago - and in a non related field).

You think you're kidding, but why is this such a bad idea? Why shouldn't we be making an effort to plan extremely long term research projects? Maybe millions of years is a bit extreme, but how about centuries? Or even decades? What can we get started on?

Humanity doesn't shy away from engineering projects that will require decades or even longer. We have run informal experiments on these timescales, as well.

Why not plan for the future? Leave a legacy of science to future generations. Even if the original purpose of an experiment is superceded, the data collected can be valuable in ways we can't imagine. Let tomorrow's data miners unlock the secrets of the universe, instead of just developing new techniques to sell me crap.

I'm still waiting for a "radio" topic first post. That'll be worth hanging round for - as rare as this dripping.

The last two years has seen the Australian broadband market go completely to hell. I've been in London for that time, and it has BAFFLED me to watch the prices in the UK go DOWN and the prices in Australia go steadily up. London is a crumbling, old, busted metropolis. Half of everything doesn't work, or breaks down regularly, or is just a pile of crap. And yet, I've had solid ADSL broadband in London for 2 years, and not a single problem. In fact, the price DROPPED from 50 pounds a month to 30 a month, and everything continued to be excellent. My ISP in London was Nildram if you're interested, they rock.

Compare this with Australia, with its modern telecoms, new cities and usually quite progressive technology attitudes, and it's completely ass-backwards to see prices spiralling upwards and service agreements becoming increasingly more ridiculous. Caps are a stupid, stupid idea and I CANNOT believe that US companies are considering them. The article pisses me off because it makes it sounds like caps are this fabulous, innovative idea. Caps do little to stop the main problem, which is network overload. Bandwidth limits are far more effective at controlling usage spikes, as well as being easier to implement (no need for counters or cutoffs).

I'm back in Australia now, and I feel like I've gone back in time to the Dark Ages. I'm already looking into satellite links and WiFi connections through groups such as the Brisbane Mesh as well as up and moving to Canada. I'm hoping the high level of competition in the USA nukes capping over there, because it really sucks.

What are some of my fond memories?

• The April 1980 April Fool's Day issue. The title of the issue was a take-off of DDJ's original title. You could turn it over and have another take-off magazine. It had the TRASH-80, "2000 hours later I still own a Lemon", ADVENTURE in Fortran printed in microscopic type, take-offs of the Appel/Haken 4-colour theorem proof, make your own barcode reader spoof, and parodies of many other magazines.
• The "Inside Dreck" column by "John Qwerty" sometime in '84 or '85. These days a magazine would be sued for that, but Dvorak hasn't changed in all those years. It's not in the on-line archive, probably for legal reasons...
• The first three months of the IBM Images column with Will Fastie - "Here is a picture of the author's personal computer" - for the first three months he couldn't get hold of one, so we had a picture of a bottle of wine, a basketball court, etc.
• Endless source code listing with explanations, CREATIVE clever programming. Astronomy programs. Hunt the Wumpus listings, dodecahedra. "Chess C-4". Checkers programs. I know I sound like an old fogey but there's nothing like this now... which leads me to...
• Dave Ahl's sad farewell, explaining the reasons for the closure of the magazine. Advertising revenue was down, leading to the magazine looking really anorexic at the end.

That's right. I used the value of the eath's diameter for its radius. Substituting half of the value in my original calculations, I come up with: 11.294 KM/s.

Also, remember that I used an upper bounds; I said that an object would fall "less than 10 meters" in 1 second, since at the end of the second it would be going 9.8 m/s^2, so even if it acccelerated constantly at the greatest speed it will reach, it will only go less than 10 meters.

More precisely, this value is:
distance = initial distance + initial velocity * time + 1/2 g times time squared.

So, d = 1/2 (9.8), or 4.9. I guess if I'd had a better conceptual understanding, I would have realized initially that after 1 second, the total displacement is just half the acceleration, since I have enough calculus to know that the derivative of a quadratic is just twice linear, and at this point we start at 0, so the graph isn't translated at all.

Anyway, if instead of 0.01 for 10 meters, I add 0.0049 KM to the original 12756 KM (now 12756/2), my answer becomes: 7.905 KM/s.

In other words, almost precisely your "8.3 km/sec or thereabouts".

So, I had just two problems.
1. I used the diameter of the Earth for its radius.
2. I did not look up the simple formula to get a more precise value than my upper bounds, and did not have the conceptual framework to quickly realize that calculation isn't necessary.

Actually, I wonder now whether my answer isn't more correct than your 8.3 km/sec...I seem to be using more precise numbers, because you're using 7000 km, whereas 12756/2 is actually 6378 KM. (And the former number comes from NASA).
Actually, now that I think about it, when I put in 14000 for 12756 in my calculations, my answer is 8.282.
In other words: Our methods produce an equally correct result.

I do wonder though why you say something like "not a bad way to do the calculation, without access to calculus." I'm in calculus 1 now, and it might be helpful if you told me what in calculus would have helped me carry out the calculations.

-Robert.

PS. It occurs to me that "7.905 KM/s" is a number I arrived at using NASA's very precise "The diameter of the Earth at the equator is 12,756 kilometers (km)" [good, apparently, to 5 significant digits] and the accepted number 9.8 m/s for g, on average.

Googling "7.905 KM/s" returns two links, the second of which says:
" See if you can show that the orbital velocity at the Earth's surface (i.e. the speed required for a frictionless train moving through an Equatorial tunnel to be in free fall all the way around the Earth) is 7.905km/s."
This page is in the webspace of Jess Brewer, who appears to be a serious researcher at the University of British Columbia.

Googling /sec instead of /s, I get a page at Purdue University reading "Thus for Earth,
vc = 7.9 km/sec (~ 5 miles/second)
(to achieve a circular orbit about the Earth)" and another (cache) by a different professor carrying out the same calculations.
Both professors are physicists.
Searching "7.90 km/s" (ie with one fewer sigfig) returns "v_cir = [ G M_E/ R_E]^{1/2} = 7.90 km s^{-1} " here. This is also an academic site.
Rounding to 7.91 returns no relavant matches, but 7.9 (as many sig. fig.s as we had from g ~ 9.8) returns too many for me to look through. Adding "orbit" I find this page says "Remember: near earth orbital velocity is 7.9 km/s." Sounds authoritative.

So you see, my calculations are quite correct. :)

Features | Chess | Go
# moves in a game | ~80 | ~300
Branching factor | ~35 | ~200
Horizion effect | Applies basically at Grandmaster level | Applies at beginner level
End of game | Strictly defined checkmate | Loosely defined territory conquest(see seki and ko fights)
Evaluation of board position | Correlates to number and quality of pieces on board | Poor correlation with either pieces or territory

A quote from his paper may also help,

"3.3 Why Go Cannot be Programmed Like Chess

Chess programs typically use a heuristic search and evaluation technique. Search trees of board positions are generated to a fixed depth and are heuristically pruned according to an evaluation of the merit of the board positions. This approach works well in Chess because the board size is sufficiently small and the nature of Chess is more tactical than strategic.

Evaluation of a board position in Go presents problems not encountered in Chess. Go is a much more strategic game in comparison to Chess. Unlike Chess, Go does not focus around the capture of a single piece. Positional advantages are slowly built up in achieving the long term goal of acquiring more territory than the opponent. There are many direct and indirect ways to achieve this goal such as making territory, building influence, attacking weak enemy groups, securing friendly groups, destroying enemy territory etc. Due to the large size of the board, a Go game is comprised of many small local skirmishes. If a game of Chess were described as a battle, a game of Go could be described as a war. Many good tactical moves at the local level must all compete for selection in the context of strategic global considerations. Thus a player must balance resources to achieve local goals at many locations whilst trying to pursue an overall global objective."

Read more about computer Go at Mike's Computer Go. Sit down and try a game of Go for yourself and you will see why computers won't get to the same level anytime soon.

crulx

The ninth drop is/was forming after the 8th drop fell in november of 2000.

The actual experiment abstract has the info as well as the calculations.

That's a great hairdo on the Sixth Drop chick

As a UQ student, I'm lucky enough to see it once a week. Since its last drop, there's now a big long tail from the drop to the funnel. I imagine that, just like before a drop, the physics staff and students will gather round and place bets on when they think it'll break off. Apparently there is a fair bit of money in it...

And this is just one example of how our Federal Government's massive spending cutbacks on higher education, and the consequent reduction in spending on research, can produce breakthroughs in science. But of course, our biggest breakthrough is our Scramjet program -- NASA's hundreds of millions of dollar and hundreds of brilliant scientists and engineers, we did for A$1.5 million (that's about US$7.84), a couple of basements full of shock-tunnels, some second-hand rockets, and a handful post-grad students.

Finally, seeing as everybody enjoys looking at UQ web cams so much, you can also view FoyerCam, an incentive to make us messy students keep out foyer clean in our computer science building. There's more cams here, but having 2 servers /.ed will probably land me (or somebody else) in a great deal of trouble. And of course, no visit to UQ is complete without a visit to kewn.

In fact, another page confirms that the 8th drop fell in November 2000, so it is indeed the 9th drop forming.

• "Technically speaking, the eighth drop in Parnell's famous Pitch-Drop demonstration experiment "fell" at the end of November last year, while I was overseas. Unfortunately the high-tech webcam's digital memory also suffered a bout of amnesia at the crucial moment. That was not all, however. When Parnell set up the demonstration in 1927 he could not have foreseen that during the gestation years of the eighth drop the University would decide to air-condition the two large lecture theatres in whose foyer the pitch resides, thus reversing the drop's seasonal experiences. That drop became by far the largest in the series, and when the time arrived for it to fall there was insufficient depth to the bottom of the beaker below for it to suffer a complete break."

The two numbers are right next to each other no matter where on the keyboard you look. I can imagine someone mistyping it... it's not as if the page needs updating all that often. (Looks like the last update was 9 Apr.) Here's hoping they read /., notice this thread, and make the change. (Yeah, right.)

According to the website "that now, 72 years later, the eighth drop is only just about to fall.", it seems 7 drops have fallen so far and the 8th not the 9th drop is now forming. Although this seems like a minor detail, it's a 12% difference in the number of drops, which given that pitch has a computed viscosity of over 100 billion times that of water, 12% could add up to a lot.

There's a ton of photos at http://photos.cc.uq.edu.au/HYSHOT/ and also at http://www.mech.uq.edu.au/hyper/hyshot/HyShot_phot os.html. The former link has some friggin huge jpegs.

There is also a page about the HyShot program itself at http://www.mech.uq.edu.au/hyper/hyshot/

There's a ton of photos at http://photos.cc.uq.edu.au/HYSHOT/ and also at http://www.mech.uq.edu.au/hyper/hyshot/HyShot_phot os.html. The former link has some friggin huge jpegs.

There is also a page about the HyShot program itself at http://www.mech.uq.edu.au/hyper/hyshot/

There's a ton of photos at http://photos.cc.uq.edu.au/HYSHOT/ and also at http://www.mech.uq.edu.au/hyper/hyshot/HyShot_phot os.html. The former link has some friggin huge jpegs.

There is also a page about the HyShot program itself at http://www.mech.uq.edu.au/hyper/hyshot/