Search found 41 matches

by webb.am
Sun Jul 04, 2010 10:04 pm UTC
Forum: Computer Science
Topic: Human performable memory hash
Replies: 16
Views: 4889

Re: Human performable memory hash

Most of these algorithms are amenable to mental arithmetic, or quick BOTE calulation: http://en.wikipedia.org/wiki/Check_digit . A cute mnemonic scheme I read about years ago in one of Martin Gardner's articles associates a consonant with each digit. You add vowels where necessary to convert the re...
by webb.am
Sat Jul 03, 2010 4:24 pm UTC
Forum: Computer Science
Topic: About solving halting problem on more general case
Replies: 128
Views: 13849

Re: About solving halting problem on more general case

Well, I've just read all of that and really wish I hadn't. I'm still not entirely sure what you're asserting. Are you saying that you have an algorithm that, when given an arbitrary, deterministic TM/CA/whatever, can determine whether it will halt, even in the case that it never halts and never fall...
by webb.am
Sun Jun 06, 2010 5:14 pm UTC
Forum: Computer Science
Topic: Why can't we talk to our computers yet?
Replies: 51
Views: 8465

Re: Why can't we talk to our computers yet?

If you make a speech recognition system and you actually want it to understand what you're saying (and perform well), you're going to need to reduce the natural language to some kind of logic. Even ignoring the difficulty of knowing how to do this, reasoning about something as 'simple' as propositio...
by webb.am
Fri May 14, 2010 10:23 pm UTC
Forum: Science
Topic: public misconceptions
Replies: 1073
Views: 149825

Re: public misconceptions

I read an article in a local newspaper today about the logistics of interstellar travel. It was written in layman's terms, but was pretty accurate until the end. The last section was about the difficulties of communicating with a probe that's several light-years away (a round-trip-time measured in y...
by webb.am
Sun May 02, 2010 12:21 am UTC
Forum: Science
Topic: Maximum angle of deflection?
Replies: 3
Views: 1482

Re: Maximum angle of deflection?

If one ball hits another, stationary ball so that it just clips the side of it, the second ball will move away in a direction extremely close to 90° to the direction of motion of the first ball. It can't move away at 90° obviously, but can be arbitrarily close to it (and the speed of the second ball...
by webb.am
Tue Mar 30, 2010 10:22 pm UTC
Forum: Science
Topic: Free Energy
Replies: 44
Views: 4955

Re: Free Energy

Europa's oceans remain liquid for the same reason; because the gravitational pull of Jupiter causes massive tidal effects. The energy is actually coming from both the planet and the moon losing rotational energy, so the end result is the moon becoming tidally locked. In other words, to get energy ou...
by webb.am
Tue Mar 30, 2010 7:14 pm UTC
Forum: Science
Topic: Free Energy
Replies: 44
Views: 4955

Re: Free Energy

Free energy / perpetual motion machines are funny because, with a lot of designs, it's really difficult to see why they're impossible. Anyone in need of procrastination material should have a look at the museum of unworkable devices: http://www.lhup.edu/~dsimanek/museum/unwork.htm ... it does a good...
by webb.am
Mon Mar 15, 2010 2:32 am UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

The last digit of pi thing was discussed several pages earlier. You both think your answer is right and that it's obviously right. But there is no correct answer because we're talking about a concept that (as far as we know) doesn't make sense: an infinitely fast computer. 1) There is no last digit ...
by webb.am
Fri Mar 12, 2010 9:30 pm UTC
Forum: Science
Topic: Free energy and the meaning of life
Replies: 15
Views: 1887

Re: Free energy and the meaning of life

What? That's a stupid senseless question? Well, so are questions about the purpose of life. Agreed. People only search for a purpose of life because it would be nice if there were one. And as my high school English teacher once said: "What does what we want have to do with anything? The truth ...
by webb.am
Fri Mar 12, 2010 5:50 pm UTC
Forum: Coding
Topic: Do/Until Statements
Replies: 11
Views: 1408

Re: Do/Until Statements

do
{ ... }
until (condition)

is the same as

do
{ ... }
while (!condition)

So it wouldn't add any extra functionality
by webb.am
Thu Mar 11, 2010 6:55 pm UTC
Forum: Coding
Topic: Coding Newbie
Replies: 12
Views: 1633

Re: Coding Newbie

A lot of CS programmes start people off with Java, because it shares traits with a lot of other programming languages and it's less messy (and has fewer features) than say, C. I don't know if it's because it's the first programming language I learned but Java seems newb-friendly to me. I'm sure othe...
by webb.am
Wed Mar 10, 2010 9:29 pm UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

We don't have AI because we don't know how to build / program one yet, not because machines necessarily lack something that biological entities have
by webb.am
Wed Mar 10, 2010 1:50 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0712: "Single Ladies"
Replies: 109
Views: 31489

Re: "Single Ladies" Discussion

As hilarious as this was... Gil-Galad throwing Sauron out of Lindon refers to the War between the Elves and Sauron. Sauron waged this war after the One Ring was created, in order to gain control of the Three Elvish Rings. Ergo, chronologically, the comic is very much incorrect. Arda, the world of M...
by webb.am
Wed Mar 10, 2010 1:51 am UTC
Forum: Coding
Topic: [fixed] c++, errors when freeing memory
Replies: 4
Views: 822

Re: c++, allocating memory and getting errors when freeing

Yeah, looks like that was the problem.

Fixed, thanks!
by webb.am
Wed Mar 10, 2010 1:08 am UTC
Forum: Coding
Topic: [fixed] c++, errors when freeing memory
Replies: 4
Views: 822

Re: c++, allocating memory and getting errors when freeing

Whoops... that typo was in the post only, not the original code =P
by webb.am
Wed Mar 10, 2010 12:55 am UTC
Forum: Coding
Topic: [fixed] c++, errors when freeing memory
Replies: 4
Views: 822

[fixed] c++, errors when freeing memory

I'm allocating memory for a 2D array in the following way int** array = new int*[size]; int i; for(i=0; i<size; i++) array[k] = new int[size]; And it all works fine, until I come to free the memory int i; for(i=0; i<size; i++) delete array[i]; delete array; It's the bit inside the loop that's causin...
by webb.am
Mon Mar 08, 2010 10:12 am UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

But lets assume we can create something more intelligent than ourselves. That in no way means that whatever we created can also create something more intelligent than itself. Why not? We were smart enough to build something smarter than ourselves. Why can't it? You're making assumptions and taking ...
by webb.am
Mon Mar 08, 2010 3:00 am UTC
Forum: Science
Topic: public misconceptions
Replies: 1073
Views: 149825

Re: public misconceptions

- The sun is either the largest or smallest star in the galaxy/universe Oh god yes. I had someone tell me today that they thought the sun was the largest star in the universe. Another annoying one: Most people think of black holes as vacuum cleaners. Try explaining it's perfectly possible to orbit ...
by webb.am
Mon Mar 08, 2010 12:39 am UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

Hang on, where is this "nothing can create an entity more intelligent than itself" idea coming from? 'Simple' example: 1) Create a simulation in which people live. Reproduction is done in the normal way. 2) Put them in a virtual environment which favours intelligence. 3) Run for a few bill...
by webb.am
Wed Mar 03, 2010 10:22 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0627: "Tech Support Cheat Sheet"
Replies: 182
Views: 54899

Re: "Tech Support Cheat Sheet" Discussion

I do the googling step before clicking random buttons, I find it saves time.

Used well, Google and Wikipedia pretty much turn you into a cyborg
by webb.am
Fri Feb 26, 2010 3:49 pm UTC
Forum: Coding
Topic: dynamically size multidimensional arrays in C/C++
Replies: 23
Views: 5347

dynamically size multidimensional arrays in C/C++

Has anyone else noticed how awful C is for dynamically sized arrays? One dimension is fine. In C++ you can do: const int a=10; const int b=20; int* exampleArray = new int[a]; . . . delete exampleArray; exampleArray = new int[b]; Now, to me, it seems like common sense that you should be able to do: c...
by webb.am
Thu Feb 25, 2010 11:01 pm UTC
Forum: Computer Science
Topic: Let's talk about AI
Replies: 60
Views: 11768

Re: Let's talk about AI

For me the moral problem comes from the fact that when we eventually make a true, sentient AI we'll probably design it badly. It we ever create intelligence with anything remotely like emotions it'll probably suffer. Human emotions are finely balanced. Feeling good=reward, feeling bad=punishment, an...
by webb.am
Thu Feb 25, 2010 10:39 pm UTC
Forum: Mathematics
Topic: Confused about countably/uncountably infintite...
Replies: 22
Views: 3945

Re: Confused about countably/uncountably infintite...

Whoops, I did mean real numbers. Luckily I don't have a math licence for you to revoke...
by webb.am
Thu Feb 25, 2010 10:08 pm UTC
Forum: Mathematics
Topic: Confused about countably/uncountably infintite...
Replies: 22
Views: 3945

Confused about countably/uncountably infintite...

Yeah, I'm a computer scientist, not a mathematician, and this is one of the things that confuses me... I know that the natural numbers are countably infinite (because you can just iterate through them). And that rationals reals are uncountably infinite. I also know that, for any given programming la...
by webb.am
Thu Feb 25, 2010 9:36 pm UTC
Forum: Computer Science
Topic: Let's talk about AI
Replies: 60
Views: 11768

Re: Let's talk about AI

Yes we create intelligence every time someone has a kid, but that's very different from trying to create a true AI. When you have kids you know (pretty much) how they're going to turn out. They'll be people. (I'm not saying we should stop trying to create decent AIs, just that there are many moral q...
by webb.am
Thu Feb 25, 2010 3:29 am UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

The same thing goes for the infinite loop argument. It makes no sense either because we're defining it badly or because the idea or an infinitely powerful computer is nonsense. 1) We have an infinite loop. If you go through the loop n times, there's always an n+1th iteration. 2) We have a machine. I...
by webb.am
Thu Feb 25, 2010 3:22 am UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

I'd calculate Pi Graaah you can't do this math fail. Pi doesn't *have* a last digit. You can't find it, no matter how fast your computer is. Same with the gorram infinite loop thing. [/minirant] That quote is taken out of context. I said I'd calculate Pi to find the starting position of any sequenc...
by webb.am
Wed Feb 24, 2010 11:44 pm UTC
Forum: Mathematics
Topic: defining the area between two lines
Replies: 3
Views: 730

Re: defining the area between two lines

Ah! p diff = p 1 - p 0 l = p 0 + c* p diff + d* v where c ranges from 0 to 1 and d ranges from -∞ to ∞ In other words, all points lie, in relation to p 0 , some length along v and some length up to the magnitude of p diff along p diff Does that make sense? Am I right? :S edit: thanks for the hint
by webb.am
Wed Feb 24, 2010 11:06 pm UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

It does seem kind of strange that they'd be copyrighting subsections of a mathematical constant though
by webb.am
Wed Feb 24, 2010 10:58 pm UTC
Forum: Mathematics
Topic: defining the area between two lines
Replies: 3
Views: 730

defining the area between two lines

If I have two position vectors p0 and p1, and a direction vector v, and I define two lines as follows

l1 = p0 + cv
l2 = p1 + cv

How do I define the geometry of the area enclosed by the two lines? :?
by webb.am
Wed Feb 24, 2010 8:41 pm UTC
Forum: Hardware
Topic: Keyboards
Replies: 2
Views: 1045

Keyboards

I'm always frustrated by the fact that I can think faster than I can type, so I've been looking for more efficient keyboard designs/layouts. Some people claim the Dvorak keyboard layout is more efficient than Qwerty, but there doesn't seem to be much evidence. So I've been looking at chorded keyboar...
by webb.am
Wed Feb 24, 2010 8:09 pm UTC
Forum: Computer Science
Topic: Turing machines
Replies: 15
Views: 4292

Re: Turing machines

As others have said, Turing machines aren't supposed to be practical computers. But they have very simple rules and anything that is computable is Turing computable. The really significant thing about Turing machines is that they brought about the concept of Universal Turing Machines. Until a certai...
by webb.am
Wed Feb 24, 2010 7:08 pm UTC
Forum: Mathematics
Topic: Base pi
Replies: 38
Views: 12189

Base pi

Does anyone else find non-integer bases fascinating? 10 π = π A circle with diameter 1 π has a circumference of 10 π Yeah... I'm not a mathematician so I can't really say anything interesting about them, but what about base π, base e, base φ? What does e look like in base π? Are non-integer bases in...
by webb.am
Wed Feb 24, 2010 6:36 pm UTC
Forum: Computer Science
Topic: Let's talk about AI
Replies: 60
Views: 11768

Re: Let's talk about AI

In fact, the more I think about it, it's pretty damn obvious that you should start with a human brain and make it more computer-like rather than try it the other way around. The brain is extremely complex and not yet understood at all. It can also regenerate/heal. I can't even imagine trying to desi...
by webb.am
Wed Feb 24, 2010 6:21 pm UTC
Forum: Computer Science
Topic: Let's talk about AI
Replies: 60
Views: 11768

Re: Let's talk about AI

Hmm. I think the key is massive parallelism with simple components. E.g. the human brain has around 10 11 neurons communicating along 10 15 connections. Of course if you built something like that you'd need to know how to program it, but I think the physical structure is the key. A neural network re...
by webb.am
Wed Feb 24, 2010 5:36 pm UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

I'd also determine if there were such a thing as a single aperiodic tile (that is, a single tile that can tile the infinite plane, but can only tile it in a non-periodic way).

Conventional wisdom says it doesn't exist, but you never know
by webb.am
Wed Feb 24, 2010 5:25 pm UTC
Forum: Computer Science
Topic: What would you do with an infinitely fast computer?
Replies: 818
Views: 224978

Re: What would you do with an infinitely fast computer?

I'd calculate Pi, break the sequence into groups of 3 digits and treat them as ascii codes. Then I'd find the first occurrence of "Help, I'm trapped in a universe factory" in the sequence Then I'd do the same thing with my favourite novels etc. In fact, there are so many fun things you cou...
by webb.am
Wed Feb 24, 2010 2:51 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0706: "Freedom"
Replies: 122
Views: 27298

Re: "Freedom" Discussion

Yeah I think most of these thoughts are about ways you could ruin your life easily and quickly. Examples include: - punching your boss - punching a pregnant woman - calling your girlfriend fat - going on a gambling website, going straight to the roulette and putting all your money on red Anyone got ...
by webb.am
Wed Feb 24, 2010 2:26 pm UTC
Forum: Science
Topic: Life in our Galaxy: Likely or Not?
Replies: 70
Views: 6345

Re: Life in our Galaxy: Likely or Not?

As many people have said, the Drake equation is pretty much useless. My gut feeling though is that the universe is absolutely teeming with something like single-cell organic life. As for intelligent life (at least as intelligent as a human being, at any technological level), the probability of it oc...
by webb.am
Wed Feb 24, 2010 1:19 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0706: "Freedom"
Replies: 122
Views: 27298

Re: "Freedom" Discussion

Oh, and the other common one: the inexplicable urge to throw your phone/keys/wallet into a lake/river...

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