Thursday, January 19, 2012

CultureLab - The algorithms alive and kicking all around us

Kevin Slavin, entrepreneur and educator. Watch his 2011 TED talk on how algorithms shape our world
algorithms.gifTO UNDERSTAND the hidden infrastructure of the universe, many people turn to theoretical physics or evolutionary biology. But as our lives are increasingly filled with interactions driven by complex informatics, perhaps literacy in this area is just as crucial to understanding our world.
Everything from the stock market to movies and the media is the result of algorithms optimising against taste, demand and opportunity. Algorithmic compression determines how we see everyday images and hear music. E-commerce transactions have complex algorithms to ensure their security. And of course, every online search result is determined by algorithms that quantify and rank the value of information.
In Nine Algorithms that Changed the Future, John MacCormick aims to illuminate what underpins all of this - and just about everything else that involves a computer. It's an ambitious task, but with two mathematics degrees, a PhD in computer vision and a fistful of patents, he is well qualified for it.
The algorithms he explains include Google's PageRank, and those behind data compression, pattern recognition and digital signatures. There's also a chapter on "an algorithm that would be great if it existed" based on a concept called the halting problem, which concerns whether a program will run indefinitely.
In his conclusion, MacCormick expresses his surprise and delight at discovering the algorithms that he had focused on all had "some simple yet clever trick at their core - a trick that could be explained without requiring any technical knowledge".
At its best, the book delivers on its ambition. The chapters on data compression and error correction, for example, do a good job of revealing complexity through simplicity and may well change how you see the computer-mediated world. The next time you see a low-quality image on a website, blurry and full of colour-shifted artefacts, you'll know what system was used to produce it, and what compromises it was accommodating. Understanding exactly how data gets compressed changes how you think about the data that's piling up around you.
But the use of stories to explain algorithms occasionally falls short. Outlining the principles of public key cryptography, for example, he relies on the metaphor of three guests at a party. Two need to communicate in front of the third, while still sharing secrets with each other. Useful enough, but when we are asked to imagine they will do so by privately mixing paint in buckets before setting them down in the middle of the party, it becomes a struggle. The story is not easily digested, nor does it present the important concepts in a straightforward way.
Overall though, MacCormick leaves the reader with a sense of the engine that powers the networked world. And at its best, Nine Algorithms enables you to recognise the real world and begin to see those algorithms alive and kicking all around us.

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