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Comment Re:I believe this violates the Outer Space Treaty (Score 5, Insightful) 256

I am not a legal expert but I believe their plan to produce a nuclear-armed spacecraft violates the Outer Space Treaty (to which Russia is a signatory) and specifically Article IV which says "States Parties to the Treaty undertake not to place in orbit around the earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner." (which sounds like exactly what Russia wants to do)

Then again, with the way the Russian economy is these days, I dont think they have the funds to actually build or launch this thing so it wont matter...

Sounds like it's planned to only ascend when needed, so nothing stationed in space. (And in any event, not in orbit until the point where treaties are moot.)

Comment Re:FP (Score 5, Informative) 152

I read it too, and I fail to see the breakthrough. There are plenty of pseudo random number generators, such as the Mersenne Twister, with very long periods, so just occassionally XORing even a poor quality random number into the feedback loop, is enough to make it completely unpredictable.

Mersenne Twister is pretty much the standard for simulating a uniform distribution in a lot of scientific computing. These depend not only upon unpredictability (useful for avoiding biases, and clearly important in the security realm), but also upon properties of the uniform distribution.

But when we test it out, we find it's still not as great as we'd like: look at a histogram of outputs, and you'll see that until you get really large numbers of function calls, the histogram isn't particularly uniform. (In particular, numbers near the bottom and top of the range don't get called quite as often.) This means that simulation properties that rely upon uniform distributions over both long and short time periods may be thrown off, and short- and mid-time simulation results may well stem from the MT rather than from the mathematical model. Moreover, low-probability events may have artificially smaller probabilities in the simulations (because of the non-uniformity of the distributions near the bottom and top ends of the range).

Over very short numbers of function calls (a few hundred to a few thousand), the outputs can even tend to cluster in a small neighborhood. So suppose that you are simulating a tissue with many cells, and calling MT as your uniform distribution to decide if the cells divide or stay dormant (each with independent probability p, so each cell divides if PRNG/max(PRNG) < p). The math says that for a uniform distribution, you don't need to worry about what order you evaluate your decision across all the cells. But if the PRNG outputs cluster over several sequential calls, then a neighborhood of cells may simultaneously divide if they are all evaluated close to one another sequentially. In analyzing the spatial behavior of such a simulation, you may draw incorrect conclusions in smaller spatial structures that, again, derive from non-uniformity of the PRNG, rather than problems with predictability. (And then you may accept/reject a particular hypothesis or mathematical model pre-maturely.)

So, there's definitely more to it than just unpredictability, depending upon where the code is being used.

Comment Re:Serious question - why not just publish to publ (Score 4, Informative) 191

I'm not in academia, but I've published a bunch of (mostly IT security) research to be freely read by the public under my own copyright or the copyright of a company that's hired me. My serious question is: what is to prevent individual researchers from just publishing what they have as a PDF or WordPress article on a random site on the Internet? (e.g. are there rules in their contract that says they can only publish through so-and-so service, who has the copyright of academic research, etc.)

In part, this is what preprint servers like arxiv and bioarxiv are for.

However, there are deeper-rooted, cultural issues at play here. Academics are rated on their job performance (for keeping your position, finding tenure-track positions, and later attaining tenure) based upon their peer-reviewed publications. Traditionally, this has meant going through the private, paywalled journals.Likewise, getting grants requires publications in peer-reviewed journals, rather than just posting online.

Now, posting in open access journals (like the PLOS family of journals, PeerJ, etc.) helps here, since at the least the access isn't paywalled. But now the academic / lab itself has to pay a much larger publication fee. (Often on the order of $1500 per article.) Moreover, many of said tenure review panels and grant review committees judge you not just on whether you've published, but where. Impact factor matters, and that again tends to steer people towards glammy, paywalled journals like New England Journal of Medicine (which just made a big kerfluffle about research parasites), Nature, Science, etc.)

So, there's a lot going on here. And even the scientists who want to just post preprints and move on are facing tremendous pressures.

Comment Re:8 seconds (Score 3, Informative) 68

How does that actually happen with a smart phone? I mean it's not like you're going to download ISOs to your phone and ...

Mobile hotspot.
For when you don't want to pay the outrageous wifi charges at a hotel conference center, or Starbucks' connection is flaky, or Charter / Comcast / Timewarner crashes for the evening and you have work to do, or ... etc.

Comment Re:Too late (Score 3) 454

A bit unrelated: I was just browsing your website (the one in your signature), and was noting that I couldn't watch the embedded youtube video (talking about this video). They are included as html object element and require flash to be played (which I don't have). Its better to support HTML5 as well by using a more modern embedding code via iframes. It will still offer a fallback for users who can't play back html5 videos, e.g. on outdated browsers. You can get the embed code by clicking "share" and then "embed".

Ah, thanks for the reminder! I worked on embedding those videos back in the HTML4 strict days. (And before YouTube, we had XVID-encoded AVI files, with a support page on how to play the videos. :-/ Embedded video has come a long, long way!)

I completely agree--they should be embedded as real HTML5, particularly as browser support is much more widespread now. And the "share / embed" code works very well for that now. I'll try to get back to it over the weekend.

Thanks for dropping by and giving the work a look! I plan to submit a method paper on PhysiCell (the 3-D agent-based model in the video you linked) and open source it soon. I should have some much cooler videos available for you then. ;-)

Very best -- Paul

Comment Re:Too late (Score 4, Interesting) 454

For what it's worth, we're keeping our NCI-funded cancer/biology projects there for the time being. (We just posted our 3-D diffusion code there in December, and we're about to post 3-D agent-based models and parameter estimation code.) SourceForge was a good and user-friendly home to me when I just got started in open source, so I'm happy to keep trying it now and see where it goes.

We may have some feature requests down the road (some of which may already be there, but hidden behind UI design) ...

Thanks for all your work. -- Paul

Comment Bring back something like freshmeat? (Score 4, Interesting) 1839

I miss the old days where there was a side bar freshmeat feed of new SourceForge releases. Could we possible increase the SlashDot / SourceForge links this way? A running feed of releases would be nice, and it would help bring us back to our FOSS roots.

Also, in the scientific community (I'm in the cancer simulation field), "grand challenges" are popping up, where there would be a dataset or two, and a challenge to create an analysis or modeling tool for those data. Some really amazing creativity can emerge from those challenges.

It would be interesting if such a thing could be done here, similarly to the "ask slashdot" articles, but then linking to a development space on SourceForge to keep it going. I would love to engage the developer community here on our data standards and other cancer projects, and I hope they'd like to pitch in.

Thanks -- Paul

PS: Please consider stopping the SourceForge spam. I'm not sure I need any more "SourceForge Resources" emails on "Flash Storage for Dummies" and business intelligence / analytics / etc.

Comment Re:Open to Questions (Score 1) 1310

Thanks so much for introducing yourself and taking the time to respond to comments and questions.

On a related SourceForge note, I miss the old days where there was a side bar freshmeat feed of new SourceForge releases. Could we possible increase the SlashDot / SourceForge links this way? A running feed of releases would be nice, and it would help bring us back to our FOSS roots.

Also, in the scientific community (I'm in the cancer simulation field), "grand challenges" are popping up, where there would be a dataset or two, and a challenge to create an analysis or modeling tool for those data. Some really amazing creativity can emerge from those challenges.

It would be interesting if such a thing could be done here, similarly to the "ask slashdot" articles, but then linking to a development space on SourceForge to keep it going. I would love to engage the developer community here on our data standards and other cancer projects, and I hope they'd like to pitch in.

Thanks -- Paul

PS: Please consider stopping the SourceForge spam. I'm not sure I need any more "SourceForge Resources" emails on "Flash Storage for Dummies" and business intelligence / analytics / etc.

Comment First fully reusable? (Score 4, Insightful) 121

This is the first time that a vehicle has made it into space and had all components fully recovered for reuse since the NASA flights of the X-15 in the 1960s

Weren't both the White Knight and SpaceShipOne fully recovered for reuse? Wasn't that the point of the X-prize (and doing it twice in two weeks)?

links: SpaceShipOne and X-Prize.

Comment Fantastic math there, guys (Score 4, Interesting) 131

This gem caught my eye:

To test the theory some experiments were performed. A consumer quality GPS was walked around a 10m square with segment lengths of 1m and 5m. The average measured segments were 1.2m and 5.6m. That is, an overestimate of between 20% and 60%. Clearly a smaller segment length is a good idea.

That's some amazing math there. (1.2 m - 1.0 m) / 1 m = 0.2, indeed a relative error of 20%. But (5.6 m - 5.0 m) / 5 m = 0.12, a relative error of 12%, not 60%! So, let's fix this thing, with of course the opposite conclusion:

To test the theory some experiments were performed. A consumer quality GPS was walked around a 10m square with segment lengths of 1m and 5m. The average measured segments were 1.2m and 5.6m. That is, an overestimate of between 20% and 12%. Clearly a longer segment length is a good idea.

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