October 1, 2013

3D printed bee colour spaces

Think3DPrint3D has generously donated 3D printer time and plastic filament to the unusual task of rendering the usually intangible concept of honeybee colour spaces into real, physical, matter!

The Spaces

The first two spaces we printed were chosen by me, in part because I think they are theoretically interesting, and in other part, because unlike some other colour spaces they are finite sized, 3D objects.

November 29, 2012

Cybernetic music

Is it okay to post art on a science blog? Well this is kind of science, so I guess it’s kind of okay.

Here is a litte piece of computer-generated music that I created yesterday:

As Twitter user @DanieleTatti noted, it sounds like a sort of Scottish raga. But what I wanted to post about was the algorithm used to generate that ever changing sequence of pitches and warbles. It’s quite a simple idea – simple enough in fact that the whole piece is generated by the following 140 characters of SuperCollider code:

```play{ar(r=RLPF,Saw.ar([200,302]).mean,5**(n={LFNoise1.kr(1/8)})*1e3,0.6)
+r.ar(Saw ar:Amplitude.kr(3**n*3e3*InFeedback.ar(0)+1,4,4),1e3)/5!2}```

January 12, 2012

An easy synchronisation experiment

Imagine a circuit that causes a little light to flash on and off. Imagine that the frequency of that flashing is itself dependent on the light at a particular sensor. Imagine that such a circuit is placed next to another identical circuit, such that the light from each circuit is directed at the sensor on the other circuit. What do you expect to see? Find out after the break…

December 22, 2011

Another example of a computer…

Calculation of greatest common divisors is a quite complex problem for a digital computer, but not for pendulums:

The pendulums line up at the edge with frequencies given by the common divisors of their individual frequencies. For example, here is diagram of a 6Hz and a 4Hz signal, you can see that they line up with a frequency of 2Hz:

The algorithm it solves it is thought to be NP (it gets slow pretty quickly). Even though the problem it solves is difficult in the usual sense, the python code to calculate it is actually quite short (though I have deliberately made it so here):

```def gcd(a,b):
return a if b == 0 else gcd(b, a%b)
```
December 7, 2011

Example of a computer

I bought a cool toy. It cleverly computes the trajectory of a cute wagging tail without using a universal Turing machine, or anything similar.

December 3, 2011

December 2, 2011

What isn’t a computer!?!

Carrying on the great jellymatter tradition of expressing a similar opinion under a contrary title, here’s my response to James’ post about brains and computers.

Computers

Before I begin, here’s the etymology of the word computer from www.etymonline.com:

1640s, “one who calculates,” agent noun from compute. Meaning “calculating machine” (of any type) is from 1897; in modern use, “programmable digital electronic computer” (1945; theoretical from 1937, as Turing machine). ENIAC (1946) usually is considered the first. Computer literacy is recorded from 1970; an attempt to establish computerate (adj., on model of literate) in this sense in the early 1980s didn’t catch on. Computerese “the jargon of programmers” is from 1960, as are computerize and computerization.

November 22, 2011

What is a computer?

I’ve been trying to work out what is and isn’t a computer. There are some different ideas about this, and I’m not totally sure myself. So here’s some thoughts I’ve been thinking for a while and felt like jotting down, in case anyone feels like criticising. It’s the kind of question that might seem abstract or trivial (I mean, everyone knows what a computer is, right?) But I want to know when it’s fair to call something a computer or not. I’m not talking about the differences between iPads and desktop PCs and laptops and smartphones – they are obviously all computers. I mean questions like is your brain a computer.

September 22, 2011

Giganto-Satellite to Crush City

A NASA research satellite is spinning out of control and is due to crash-land today.  The satellite, which weighs 20,000 tonnes and could easily be mistaken for a small moon, is expected to explode in a deadly fireball of fiery death, engulfing an area of at least 500 square kilometers.  Its malfunctioning weapon systems were designed to target cities, and NASA expects it to obliterate one with an expected population of just over two million.  Unfortunately, because of the battle station’s unpredictable trajectory, they won’t know which population centre is doomed until about two hours before it hits, leaving precious little time to evacuate the area.  A NASA spokesperson was unavailable for comment on why a research satellite needs to be so big, how such a gigantic object was launched into Earth’s orbit, or why its trajectory is biased towards built-up areas.  However, they did release an estimate that your personal probability of being one of the millions who perish in this impending disaster is 1 in 3200…

…or at least, that’s what I was able to deduce from a news report on (Australian) telly the other day, which quoted the 1 on 3200 figure and then ran a whole segment on how much more likely you are to be hit by this satellite than to be struck by lightning, win the lottery, etc.

Of course, in reality, the 1 in 3200 figure is the probability of the debris from the falling spacecraft hitting some person, somewhere in the world, i.e. there’s a 3199 in 3200 chance that it will just plop into the ocean or crash in some unpopulated area and not hit anyone at all.  Since there are seven billion people in the world, your chance of being the one person who does get hit is 1 in 22 trillion.  You’re more likely to win the lottery and get struck by lightning than you are to be struck by debris from this particular piece of falling space hardware.  All of which was completely obvious to me the moment the news anchor quoted the figure – with just a tiny bit of thought it should have been obvious to them as well.

September 20, 2011

The Sun is not made of gas

Dawkins is expanding his shelf in Waterstones this month with a book aimed at young teenagers. I haven’t read it yet, but what made me giggle for just a second was how Dawkins sums up the chapter on the Sun (see video here, 2:30):

What really is the Sun? Well the Sun is a huge ball of gas…

Except it’s not, it’s a huge ball of plasma. Plasma is not gas. This confusion is of course entirely the fault of that They Might Be Giants song. Fortunately they corrected themselves, so this post is just an excuse to link to this video: