What
is an Algorithm?
To start with the basics, let’s look at a
definition of an algorithm. I like this
one from Whatis.com?
An algorithm (pronounced AL-go-rith-um) is a procedure
or formula for solving a problem. The word derives from the name of the
mathematician, Mohammed ibn-Musa al-Khwarizmi, who was part of the royal court
in Baghdad and
who lived from about 780 to 850. Al-Khwarizmi's work is the likely source for
the word algebra as well.
A computer program can be viewed as an
elaborate algorithm. In mathematics and computer science, an algorithm usually
means a small procedure that solves a recurrent problem.
Another way of looking at it is to say an
algorithm is a series of logically ordered instructions, rather like a recipe
for baking a cake. If you are sensible,
and use a Delia Smith recipe, you will probably end up with a beautiful
cake. If you are foolish enough to go to
a Keith Floyd recipe book, it will probably turn out to be a culinary disaster.
A Mathematical Genius at Work |
In itself, an algorithm is neither good nor
evil. As a problem-solving tool it could
be effectual or it could be useless; it all depends on the quality of the human
mind that creates and programmes the algorithm in the first place it, and
the appropriateness of the human response to the algorithm results.
The War on Terror
Thanks to revelations reported in The Guardian by ex American intelligence
analyst Edward Snowden, data-gathering techniques by government security
organisations have been hitting the headlines across the globe. The US intelligence organisation known as the National Security Agency or NSA has
been widely reported to be covertly collecting colossal quantities of data from
our phones, computers, and social networks.
Thanks to advances in communications techniques and the ease and
cheapness of current-day data storage, it is now physically and economically
feasible for them to create, maintain and interrogate these mammoth databases as they search for terrorist conspiracy activities.
The other reason for
the existence of these data monsters is that modern computing techniques make it
feasible to trawl through them. It would
not be possible for human beings to read all of that information (and it would
no doubt be an incredibly boring task, too), but algorithms can search it,
analyse it and report back to the government security agencies. These
techniques are a major weapon in the state’s armoury for the so-called war
against terrorism. We know that
algorithms are deployed by the NSA and GCHQ (the UK equivalent listening
centre, General Communications HQ at Cheltenham), but we can only take an educated
guess at the rules used by the algorithms, and hope that they are being used
wisely.
Big Brother is Watching You
Algorithmic techniques
have also been used in recent years to facilitate ‘predictive policing’ and in
some instances they have achieved dramatic successes. The idea here is to harness the power of the
algorithm to provide data to enable police to deploy their
resources in the right place at the right time.
This is sometimes known as ‘Minority Report Policing’, after the Steven
Spielberg sci-fi movie with Tom Cruise,
where "PreCrime", a specialized police department, stops crime
before it actually happens, using information provided by three psychics
called "precogs".
In the real world the technique is more
correctly known as CRUSH, or ‘Criminal Reduction Utilising Statistical
History". The
earliest example of this I could find was ‘Operation Blue Crush’, a pilot Crush
operation staged in Memphis ,
Tennessee back in 2005, and
during which 1,200 people were arrested over the course of just three days. Have a look at this link to find out more: http://www.memphispolice.org/blue%20crush.htm
Algorithms,
Quants, and the City
As a reader of this blog you are already
well aware of the power of The Geek. Did
you know that, in the city, highly-paid geeks known as ‘Quants’, or
Quantitative Analysts, are employed to create algorithms to formulate trading
strategy? The traditional picture of the
stock market trading floor peopled by traders in suits and ties making frantic telephone
calls and yelling ‘Sell, sell!’ has now largely been superseded by computer
servers running ‘algos’ to predict market fluctuations.
Most financial institutions, including
banks and pension funds, now rely on algorithms. Sometimes
competing algorithms have been known to clash, and, on occasion they have been
blamed for speeding up trading to the extent of destabilizing the market and causing
a meltdown. It’s not only the big
rollers in the city that can be affected: the ‘algo’ is also impacting ordinary
people by influencing the way their savings and pension funds are invested.
Algorithms in Everyday Life
It doesn’t stop there. The power of the
algorithm extends way beyond the rarefied world of investment and trading. Think
about dating websites, credit checks, online retailing, retailer loyalty
schemes, tailored and targeted discount
vouchers, online insurance quotations and internet search engines: they
all use the same principles to analyse our personal interests and our buying
habits.
Algorithms are being used extensively now simply
because of the explosion in the quantity, quality, and availability of data
spawned by the era of global mass communications. The technique is now so widespread and
industrialised that it is commonly known as ‘Data Mining’.
All this is nothing new, of course. Alan Turing and his team of Bletchley Park
code-breakers used algorithms to powerful effect back in the 1940s, and they
were instrumental in victory against the Nazis in World War II. This is a perfect example of an algorithmic tool
being harnessed to good effect. In the
wrong hands, and wielded unwisely, there is also the potential for it to become
an instrument of the powerful and unscrupulous who seek to dictate, repress,
control and censor.