## Search found 240 matches

Fri Mar 18, 2011 2:50 pm UTC
Forum: Science
Topic: Breaking Earth's gravity well
Replies: 30
Views: 4061

### Re: Breaking Earth's gravity well

The Schwarzschild radius of a black hole is the distance from the center within which the escape velocity is >= c. Why can't you escape from a black hole with continuous acceleration? Under Classical Mechanics black holes can't exist, basically for this reason. Also the speed of light in a vacume &...
Tue Mar 15, 2011 4:06 pm UTC
Forum: Science
Topic: Symbiogenesis
Replies: 17
Views: 1851

### Re: Symbiogenesis

Where do macro-organisms with symbiotic micro-organisms fit in this discussion? I'm thinking mainly of aquatic life such as corals and mollusks some of which get their primary nutrition from symbiotic photosynthetic organisms. My understanding is that it's similar to the relationship between a cell ...
Thu Mar 10, 2011 9:20 pm UTC
Forum: Science
Topic: A bit of help with research report
Replies: 1
Views: 355

### Re: A bit of help with research report

My experience has been that formatting like headings, chapters, citation format, etc. Is essentially arbitrary and vary between instructors. Your best bet will likely be to ask your teacher what format they want you to use, then armed with their response just try to explain yourself a clearly as pos...
Wed Mar 02, 2011 8:40 pm UTC
Forum: Coding
Topic: Why is R different?
Replies: 25
Views: 7866

### Re: Why is R different?

yes, because the compiler (or interpreter) is smart enough to realize it is ambiguous.  I've never even heard of R so i'm answering the more general question of "why would any language use '<-' for assignemt?", which the short answer is: "they have to use something why not <- ?&...
Wed Mar 02, 2011 8:27 pm UTC
Forum: Coding
Topic: Why is R different?
Replies: 25
Views: 7866

### Re: Why is R different?

In short: language design involves a lot of basically arbitrary choices. Assignemtn and equality testing are two different operations. If I use "=" to mean both assignment and comparasin I can create ambiguous code like this: A=5 B=10 print (A=B) Should that last line output "false&qu...
Tue Mar 01, 2011 9:51 pm UTC
Forum: Logic Puzzles
Topic: A very interesting Mathematical Paradox
Replies: 387
Views: 157334

### Re: A very interesting Mathematical Paradox

Most resistance to .999... = 1 stems from intuitions that are plausible but false for the real numbers (given how mathematicians have constructed the real numbers). Alternative number systems can be constructed that allow for the possibility of infitesimal non-zero numbers, and in such number syste...
Fri Feb 25, 2011 4:06 pm UTC
Forum: Science
Topic: Waterfalls... How do they work?
Replies: 28
Views: 3782

### Re: Waterfalls... How do they work?

I think it's using the "spreading" property of water to create that illusion. Think about what happens when you pour water into a flat pan with a maze-like patter of dividers. The water flows evenly and "snakes" around the walls as it moves towards it's equilibrium position. I ex...
Wed Feb 23, 2011 4:24 pm UTC
Forum: Science
Topic: Waterfalls... How do they work?
Replies: 28
Views: 3782

### Re: Waterfalls... How do they work?

A quick look at the structure shows that it can't exist in three dimensions. The support struts cross the trough in a way that looks 3-d but can only be accomplished via forced perspective in 2 dimensions (like a lot of Escher's work). Given that the structure is pretty much flat, it's probably usin...
Fri Feb 11, 2011 6:34 pm UTC
Forum: Fictional Science
Topic: Favourite faster than light technology
Replies: 92
Views: 20821

### Re: Favourite faster than light technology

Personally I'm a fan of a Babylon 5's "hyperspace". Essentially: there some naturally occurring "other space" that can via big expensive technology be accessed and used to travel faster, but navigating that space is difficult, and doing something distracting like having a battle ...
Fri Feb 11, 2011 4:59 pm UTC
Forum: Logic Puzzles
Replies: 217
Views: 66166

### Re: The surprise exam paradox

That's a contradiction. Exactly . I'm confused. Your link is to an article on a proof by contradiction. which implies that you're claiming that the students are trying to use a proof by contradiction to establish a base case for the inductive proof they use to iteratively eliminate the remaining da...
Tue Feb 01, 2011 9:45 pm UTC
Forum: Logic Puzzles
Replies: 217
Views: 66166

### Re: The surprise exam paradox

the students never establish a valid base case. they say that if the test has not occurred on day 5 than it must occur on day 5, and therefore cannot occur on day 5. thats: no (test on day 1, test on day2, test on day3, test on day 4) -> test on day 5 test on day 5 -> no test on day 5 That's a contr...
Mon Dec 13, 2010 7:38 pm UTC
Forum: Logic Puzzles
Topic: A very interesting Mathematical Paradox
Replies: 387
Views: 157334

### Re: A very interesting Mathematical Paradox

Try digging a little deeper. You can prove 1+1=2 without recursion. That pretty much misses the point. Why should I prove that 1+1=2 without using recusrion when the proof with recursion is so much easier, adiquately translatable into the silly non-formal language I wanted to use, and recursion was...
Wed Dec 08, 2010 8:01 pm UTC
Forum: Logic Puzzles
Topic: A very interesting Mathematical Paradox
Replies: 387
Views: 157334

### Re: A very interesting Mathematical Paradox

Sure you can prove 1+1=2. here's one such example (emphasis mine): P1. 1 is in N. P2. If x is in N, then its "successor" x' is in N. P3. There is no x such that x' = 1. P4. If x isn't 1, then there is a y in N such that y' = x. P5. If S is a subset of N, 1 is in S, and the implication (x i...
Wed Dec 08, 2010 7:31 pm UTC
Forum: Computer Science
Topic: Secure on-line voting
Replies: 33
Views: 3708

### Re: Secure on-line voting

it could generate long enough random strings to make the chance of collision between 2 votes in any election unlikely to the point of being on a par with getting hit with multiple meteorites on the same day at the same time. voters aren't going to be doing the math by hand after all. Assuming that ...
Tue Dec 07, 2010 6:10 pm UTC
Forum: Logic Puzzles
Topic: A very interesting Mathematical Paradox
Replies: 387
Views: 157334

### Re: A very interesting Mathematical Paradox

retarded comment spell-checked version of quoted comment. fixing the spelling didn't make it any less retarded. Thanks for the editing, as long as people like you exist I never have to do it myself :twisted: So do you like not understand what "prove" means or something No, actually my not...
Tue Dec 07, 2010 4:34 pm UTC
Forum: Gaming
Replies: 24
Views: 2545

### Re: Need advice: potty-mouth FPSers

Part of the problem is that people don't typicly think much while cursing. As such most curse words are chosen by habit and a rough scale of "harshness". Think about some common curses and you'll see that people probably don't literally mean "My toaster which is currently engaging in ...
Tue Dec 07, 2010 3:03 pm UTC
Forum: Coding
Topic: Learning about network security (legitimately...)
Replies: 3
Views: 860

### Re: Learning about network security (legitimately...)

the best way to learn about security will be to try stuff. Fortunately that's perfectly legal if you own the systems in question or have permission of the system owner. Ask your professors if there is a computer lab owned by the CS department in which you can work on projects like this. I know in my...
Tue Dec 07, 2010 2:10 pm UTC
Forum: Science
Topic: Crazy Prediction Idea
Replies: 23
Views: 3362

### Re: Crazy Prediction Idea

This was kind of the argument I was trying to make with the "simulating the brain" thread . That to simulate the universe to perfect accuracy would need the universe it's self. To do the same for a brain may not be as complex, but could have a similar outcome. If we build a computer that ...
Tue Dec 07, 2010 1:57 pm UTC
Forum: Science
Topic: Can someone explain the joke?
Replies: 16
Views: 3037

### Re: Can someone explain the joke?

Maybe the joke is that you (the uninitiated viewer) don't realize it's meaningless, or at least not inherintly funny, and all the people they've gotten to play along (for feat of looking stupid) is funny.?
Mon Dec 06, 2010 10:09 pm UTC
Forum: Science
Topic: Crazy Prediction Idea
Replies: 23
Views: 3362

### Re: Crazy Prediction Idea

Well, I suppose: 1. figure out how to quantum entangle half the universe with the other half than call one half the "universe" and the other the "simulation" 2. ??? 3. Profit! But I think that only works if you use quantum engangling for sci-fi writers, not the kind that happens ...
Fri Dec 03, 2010 6:49 pm UTC
Forum: General
Topic: stock market nub looking to get in the game
Replies: 11
Views: 1852

### Re: stock market nub looking to get in the game

As someone who fell into the "wow,. I'm doing so well on the simulator, I should try with real money" trap I have the following advice: 1. Don't let people who say you can't do it discourage you, but do understand that the way you make money is by "winning" more than "loosin...
Fri Dec 03, 2010 6:08 pm UTC
Forum: Fictional Science
Topic: Economics of time travel
Replies: 60
Views: 21110

### Re: Economics of time travel

Investing with time dilation is essentually the same as without (only you have less ability to moniter your investments). Since no information from the future is available you still have to make speculative choices that could either be right or wrong. Given the increased time of the planned investme...
Fri Dec 03, 2010 5:55 pm UTC
Forum: Logic Puzzles
Topic: A very interesting Mathematical Paradox
Replies: 387
Views: 157334

### Re: A very interesting Mathematical Paradox

Oh boy a redicilous clallange, let me: from the deffenition of addition 1+1=2 Wow, that was easy. Seriously though, the above number system doesn't make any lese sence than say: complex numbers. However it doesn't on first glance have much usefulness outside allowing people to talk about a set of i...
Mon Nov 29, 2010 9:38 pm UTC
Forum: Computer Science
Topic: Secure on-line voting
Replies: 33
Views: 3708

### Re: Secure on-line voting

It seems to me the problem boil down to this: 1. You need to know who cast every vote in order to ensure that no one voted twice. 2. If you know who cast each vote it's not seceret ballot anymore and therefore voters can't be assured of their saftey if they vote "wrong". I really don't se...
Mon Nov 29, 2010 8:57 pm UTC
Forum: Logic Puzzles
Topic: A very interesting Mathematical Paradox
Replies: 387
Views: 157334

### Re: A very interesting Mathematical Paradox

Then, we can easily have infinite sequences, followed by values that come after that, followed by more infinite sequences, and more values afterwards, and so on. For instance, if we want an infinite number of zeros, followed by a 1, this is just the sequence where all terms are 0 except the \omega ...
Wed Nov 24, 2010 9:55 pm UTC
Forum: Coding
Topic: Website development
Replies: 12
Views: 3504

### Re: Website development

If there's database work going on it could be that the old database needs to be converted/inported into the new database. During the conversion you don't want anyone using the old system (because it's being read from and you don't want it's state changing mid-read), but the new database doesn't exis...
Mon Nov 22, 2010 10:00 pm UTC
Forum: Computer Science
Topic: Secure on-line voting
Replies: 33
Views: 3708

### Re: Secure on-line voting

Here's my system that I imagined: The government generates one-ballot's-worth of random data (ideally over 100 bytes or so) for every person in the county. The government keeps the keys, makes sure that there aren't any repeats (extremely unlikely anyway), and sends a copy randomly (the government ...
Mon Nov 22, 2010 9:50 pm UTC
Forum: Computer Science
Topic: Secure on-line voting
Replies: 33
Views: 3708

### Re: Secure on-line voting

It seems to me the problem boil down to this: 1. You need to know who cast every vote in order to ensure that no one voted twice. 2. If you know who cast each vote it's not seceret ballot anymore and therefore voters can't be assured of their saftey if they vote "wrong". I really don't see...
Mon Nov 22, 2010 7:07 pm UTC
Forum: Science
Topic: Orbital Deathrays / Solar Energy Collectors
Replies: 26
Views: 3061

### Re: Nuclear Fusion

Plus any beam that is beaming us the energy collected by a solar panel the size of the moon would be, for all intents and purposes, an orbital death ray. I'm definately a fan of "Death Ray power", if for not other reason than to watch enviromentalists become really conflicted when you exp...
Thu Nov 18, 2010 9:14 pm UTC
Forum: Science
Topic: How to go faster than the speed of light.
Replies: 40
Views: 4519

### Re: How to go faster than the speed of light.

I hate to be a negative nancy, but is it not true that many of the things we currently "know" about black holes have been derived by first assuming that nothing can go faster then the speed of light? it's not like we have any real pictures of the things, and we have certainly never poked ...
Mon Oct 11, 2010 6:00 pm UTC
Forum: Computer Science
Topic: Holographic video compression.
Replies: 13
Views: 2318

### Re: Holographic video compression.

Unless I'm mistaken the OP's desired goal is to use one of the proporties of holograms, namely the fact that by cutting them apart you only make a bunch of lower quality copies of the original, not pieces of the original, as a method to prevent someone from editing out the comercial breaks in a TV p...
Mon Oct 11, 2010 5:46 pm UTC
Forum: Computer Science
Topic: voice output
Replies: 8
Views: 2077

### Re: voice output

Mostly it's because humans are analog and computers are digital.
Mon Oct 11, 2010 5:38 pm UTC
Forum: Computer Science
Topic: Can you train a neural network to recognize prime numbers?
Replies: 35
Views: 17345

### Re: Can you train a neural network to recognize prime number

This Game of Life pattern can compute prime numbers so I wouldnt be surprised if a neural network could do it too. It wouldnt be the best tool for the job, of course. The game of life is turing complete, so it can compute anything that can be computed. So stupid question: Is there an ANN structure ...
Wed Oct 06, 2010 8:05 pm UTC
Forum: Computer Science
Topic: Can you train a neural network to recognize prime numbers?
Replies: 35
Views: 17345

### Re: Can you train a neural network to recognize prime number

I can train one to identify primes in the set of integers between 1 and 3 inclusively with 100% accuracy.
Wed Oct 06, 2010 7:36 pm UTC
Forum: Fictional Science
Topic: Exchange rates for an alien economy
Replies: 34
Views: 11542

### Re: Exchange rates for an alien economy

One thing to remember is that curency exchanges are not equivilence relationships (So if 5 USD = 1 euro, and 1 euro = 20 yen that doesn't nesesarily mean 1 dollar = 4 yen). This is why your conversion system would not work, as you'll never get consistent results amoung existing curancies that way l...
Tue Oct 05, 2010 8:33 pm UTC
Forum: Science
Topic: Humans 2.0
Replies: 143
Views: 10597

### Re: Humans 2.0

Plus, you'd have 50% more chance of sex. Right, because of course bisexuals have lower standards... I would think bisexuals are by deffenition less discriminating than homo/hetero-sexuals. i mean knowing nothing other than how many genders someone prefers (and assuming all unspecified factors to be...
Tue Oct 05, 2010 8:14 pm UTC
Forum: Fictional Science
Topic: Exchange rates for an alien economy
Replies: 34
Views: 11542

### Re: Exchange rates for an alien economy

supply and demand would determine the value of the alien currecny relative to any given earth currency. the primary driving force being how much interest humans have in doing buisines with the aliens and how much interest the aliens have in doing buisnes with humans. One thing to remember is that cu...
Tue Oct 05, 2010 7:46 pm UTC
Forum: Science
Topic: What's the difference between man and animals?
Replies: 135
Views: 14746

### Re: What's the difference between man and animals?

Humans are the only animals that can create, control, and use fire. All other "differences" between us and the other animals are simply a matter of degrees. As soone as I post this, however, some researcher is going to discover some other animal species which can control fire. (I lump eve...
Fri Sep 24, 2010 7:01 pm UTC
Forum: Coding
Topic: LOLCODES: Great Language or Greatest Language?
Replies: 13
Views: 3387

### Re: LOLCODES: Great Language or Greatest Language?

I prefer ZOMBIE
Tue Aug 31, 2010 2:58 pm UTC
Forum: Science
Topic: Difference between pharmaceutical and therapeutic agents
Replies: 15
Views: 5585

### Re: Difference between pharmaceutical and therapeutic agents

Well, Knowing nothiong other than the words in question. and something about the meaning of similar words I will extrapolate the difference: Phamaciticals (similar to "pharmacy" where you buy medication and "phamacysts" someone cetified to dispence medication perscribed by a doct...