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Comment: Re:WIMPs (Score 1) 221

by lgw (#49362505) Attached to: Dark Matter Is Even More of a Mystery Than Expected

Yes, you've got the core of the scientific method right in hand. You use math to formalize some model that explains both old and new observations, then you extrapolate using the math to make predictions, then you weed out all the failures with the next set of data. Everyone in physics does understand this, except maybe the string theorists, who went off the rails some time ago and IMO are an embarrassment to the field now.

But the math is the tool that lets you make that prediction, and it's not enough for the current model to be "wrong", you have to have an alternative that successfully predicts new data. That what all the internet cranks and crackpots seem to miss: yes, fine, you can contrive limitless alternative explanations for the existing data. So what? It's all about the predictions, and those are usually meaningless without the math to back them up, to set bounds and make them falsifiable.

The inability of GR to give a good model at universe-scale is hardly new - Einstein himself identified the need for a cosmological constant quite early on. The mystery has only deepened since - but that doesn't necessarily mean anything's wrong with GR, only that there's more to learn (dark energy is easy to describe in GR terms, but GR gives no explanation of why it's there in the first place).

Comment: Re:WIMPs (Score 1) 221

by lgw (#49361253) Attached to: Dark Matter Is Even More of a Mystery Than Expected

Equations can predict, but they don't prove anything.

You've got that backwards, I'm afraid. Science isn't in the business of proof; proof is the realm of mathematics and formal logic. One can prove that one equation, or other statement in a formal language, is equivalent to another under some axioms. Once cannot prove anything about the universe we inhabit.

Science is in the business of useful, predictive models. Dark matter and energy are both "dark" in the sense that we don't have one of those yet. We can characterize them, and there's been some real progress in dark matter as WIMP models predicted the CMBR data nicely, but still, there's so little data to go on. There's a forest of hypotheses for each, and not much yet to weed them out.

If the cosmological constant is, in fact, constant, then it's remarkably close to "0", which is bothersome as it requires such "fine tuning", which is another way of saying we're missing something big. Inflation models also deal with the expansion of space, but don't seem to solve the dark energy problem in any natural way. And QM also has a similar concept: in what been called the "worst prediction ever", the value predicted from QM is wrong by 120 orders of magnitude - so no help there.

Comment: Re:WIMPs (Score 3, Interesting) 221

by lgw (#49359093) Attached to: Dark Matter Is Even More of a Mystery Than Expected

Dark energy is just the latest name for the Cosmological Constant - I guess it's a better name if it's not actually constant, but the cosmologists I've seen talking about it don't like the new name either (not that anyone has a better suggestion, really). The key thing about it is that the energy density of it is insanely low - I suspect that on the quantum scale it actually "rounds to 0" the way things can in QM, where no measurement is possible at that scale. I think even at the scale of our galaxy it's a very tiny effect. It's a testament to how sparse matter really is in the universe that dark matter is the dominant effect overall.

Comment: Re:It depends (Score 5, Insightful) 482

by lgw (#49337255) Attached to: No, It's Not Always Quicker To Do Things In Memory

How in the world? Trivially. They're doing it in an O(n^2) way - it's the only explanation.

If you use string concat library code naively, you can end up "copy the string, add one byte, repeat" easily enough in languages like Java. And it's not exactly breakthrough research to discover that O(n) disk can be faster than O(n^2) memory for large enough n.

Programming

A Bechdel Test For Programmers? 515

Posted by timothy
from the this-code-feels-different dept.
Nerval's Lobster writes In order for a movie or television show to pass the Bechdel Test (named after cartoonist and MacArthur genius Alison Bechdel), it must feature two female characters, have those two characters talk to one another, and have those characters talk to one another about something other than a man. A lot of movies and shows don't pass. How would programming culture fare if subjected to a similar test? One tech firm, 18F, decided to find out after seeing a tweet from Laurie Voss, CTO of npm, which explained the parameters of a modified Bechdel Test. According to Voss, a project that passes the test must feature at least one function written by a woman developer, that calls a function written by another woman developer. 'The conversation started with us quickly listing the projects that passed the Bechdel coding test, but then shifted after one of our devs then raised a good point,' read 18F's blog posting on the experiment. 'She said some of our projects had lots of female devs, but did not pass the test as defined.' For example, some custom languages don't have functions, which means a project built using those languages would fail even if written by women. Nonetheless, both startups and larger companies could find the modified Bechdel Test a useful tool for opening up a discussion about gender balance within engineering and development teams.

Comment: Re:Schneier got it right a decade and a half ago (Score 1) 119

by lgw (#49322509) Attached to: OS X Users: 13 Characters of Assyrian Can Crash Your Chrome Tab

Maybe I'm still not getting your point. Sure, if you need to understand the details of Unicode character composition and such because you're the one rendering the output glyphs, or you want to sort or search across different encodings of the same word, that's rough, but there's no excuse for a security failure while doing those tasks.

On your other point: the notion of "sanitizing input" is fundamentally flawed to begin with. You can never know what future framework that user data will be interacting with, and what might be interpreted as an escape sequence in that mysterious future, but you can assume that the guy doing that future work will just assume "the input was sanitized", and you're screwed. Instead, don't go there. If e.g. you need to store a user string in a SQL DB, do it in such a way that there's no possible problematic string (perhaps the DB has a way of doing queries that's guaranteed safe, for example). If e.g. you need to send a user sting inside an XML blob, just convert the user string to a hex/base64/whatever representation first - guaranteed safe.

What usecase were you thinking of that makes any of this hard at all?

Comment: Re:Would that be like the free market solution to (Score 1) 416

by lgw (#49316573) Attached to: How 'Virtual Water' Can Help Ease California's Drought

A contract would have prevented that just as well as a law, is the thing. Engineering a shortage in an attempt to corner a market is hardly a new idea - it's older than the idea of commodities markets, for sure. That's why commodities contracts are carefully written, backed up by especially brutal contract law, and market rules prevent any one entity from controlling too large a position.

All of this is centuries-old best practices, and none of it requires price-fixing.

Comment: Re:Would that be like the free market solution to (Score 1) 416

by lgw (#49315801) Attached to: How 'Virtual Water' Can Help Ease California's Drought

There are plenty of laws around modern markets. That's how they evolved. Trying to make some sort of anarchist strawman really doesn't make you look smart, you know.

What there aren't are prices fixed by law. It's really not that complicated a concept: government regulating product quality, fraud, and contracts: good; government setting prices or granting monopolies: bad.

Comment: Re:Would that be like the free market solution to (Score 4, Insightful) 416

by lgw (#49313453) Attached to: How 'Virtual Water' Can Help Ease California's Drought

You miss the point. The exact problem with retail price controls and a wholesale free market is that it's vulnerable to gaming, Enron-style. Proper markets expect every participant to be gaming the system as hard as they can. They're built on it from the start, have evolved for centuries to cope, and they work nicely for most commodities in the world - just a few government-granted monopolies left over causing problems.

Comment: Re:Having to move (Score 1) 211

Well, when a state school didn't come with a crushing debt burden, it was much less of an issue (compared to even 10 years ago it's nuts). My own solutions was to get that first job in my home city, paying peanuts, then once I had enough experience to be credible, move away. That first job wasn't so hard to get because everyone else was doing the same thing, so they were constantly hiring.

With you on the home economics. I was such a moron with money for almost the first 10 years.

Comment: Re:Maybe they should ... (Score 1) 211

Ha! That's been happening continuously since the beginning - better languages, better frameworks, etc. You almost never need to write a toolkit these days, or a script to refactor code in some simple way. I started with assembly, and for all Java's many problems, it's several times as productive. Turns out the need for programmers is mostly limited by budget, not by the universe of problems that need to be solved, and so more companies started hiring developers as the better tools made the payoff better.

Aren't you glad you're not getting all the government you pay for now?

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