Wednesday, 29 April 2009


Today a very good article was published in the Guardian newspaper on this most emotive of subjects.

The Climate Engineers - John Shepherd

Personally I'm not a big fan of the idea of geoengineering. A lot of the ideas being bounced around (such as carbon sequestration) are short term fixes to what is clearly a long term problem. Equally, a lot of these methods are likely to have side effects that we don't fully understand, since the vast majority of them involve manipulating extremely complex ecosystems (e.g., ocean fertilization). If there is one thing we really have to learn is that we cannot mess with existing ecologies and expect to get away with it scot free. For example, look at the way Austalia and New Zealand have been forever changed by the introduction of European species by western settlers.

Although John's article does not go into the particulars of the subject, it is encouraging to know that the Royal Society has decided to do something about this. It is also encouraging to hear that John will be chairing the committee. Although I cannot claim to know him well, our paths have crossed several times and he has always come across as an extremely clever and very level headed. Just what the doctor ordered!

Tuesday, 14 April 2009

The End of Mr Y

In this superb bookScarlett Thomas throws together the concepts of modern scientific thinking and physiological reasoning regarding consciousness into a thoroughly gripping yarn. To describe it simply as a novel is doing Thomas a great disservice. In truth it is really a very clever thought experiment in the classical sense of Schrodinger or Maxwell, all nicely encased in a fast-paced, entertaining adventure story. Although there are a number of reviews out there(e.g., bookslut or Katrina), here's my two penneth.

The story follows disillusioned Ph.D student Ariel Manto. Her supervisor vanished some 12 months prior to the begging of the tale, and as we begin her University is falling down. Through a series of strange events she ends up finding a very rare copy of the book 'The End of Mr Y' by Thomas Lumas, a supposedly cursed text of which there are only a couple of copies known to exist. Contained within this valuable work is the recipe to make a drug which allows one to access the Troposphere, a extra set of dimensions where all consciousnesses interact. Obviously, being the plucky young heroine in a modern adventure novel, she goes straight out to get the necessary ingredients and have a go herself. Needless to say, all hell breaks loose and and we're led on a merry old romp.

Although the basic skeleton of the story isn't something insanely creative and new, the concepts Thomas discusses along the way are what make it. Some pretty complex and very thought provoking issues are introduced, all in a manner that leaves the reader interested and wanting to know more. Somehow, Thomas manages to strike the perfect balance between being complex and engaging, without also being confusing.

The basic idea revolves around the principle that thought (i.e., consciousness) is matter, thereby enabling consciousness to take the form of a higher dimensional space. This Troposphere therefore allows you to gain access to other peoples mind and their memories. In principle, the statement that thought =  matter is true, thoughts can be observed as increased electrical activity within the brain. For me, how this ties with an extra 'consciousness' dimension is probably a step too far. But, one idea Thomas discusses along the way, is the belief that consciousness evolves in a similar way to physical traits.

This I find immensely emotive. As is pointed out, under this principle there is nothing to stop machines developing consciousness, indeed it could be thought of as being unavoidable. So, HAL or Skynet mightn't be that far off!

In conclusion, The End of Mr Y is a great book, and doesn't feel anywhere near the 506 pages in length it is. If you have an interest in the philosophical sciences then you'll find it extremely engaging, and well worth curling up with one sunny spring afternoon.

Friday, 10 April 2009

Nyquist and sampling

Due to one thing and another (mostly the one thing commonly referred to as my thesis, although I have some more personal terms for it), I haven't found the time to keep this little corner of the blog-o-sphere up to date lately. However, the blighter is just about finished (the light is most definitely in sight), which means normal service should be resumed in the near future.

In the mean time, there are a couple of things of late that have caught my attention, causing my little grey cells of curiosity to spark into life. So, with luck, I hope to take up some of the time off I'm allowing myself over Easter (ssh, don't tell the supervisors) to catch up on a little bit of blogging.

First amongst the musings I wanted to talk about is a few thoughts I had whilst looking up some information on Harry Nyquist. Anyone who has studied physics, maths, or engineering of some description must has come across him and his famous Nyquist Theorem (although, properly it should probably be called the Nyquist-Shannon Theorem).

For anyone who hasn't come across this particular idea, it is one of the fundamental principles of Information Theory (something which Nyquist and Shannon both contributed heavily toward developing). Regardless of whether you've ever studied this subject at all, it will have played a huge part in your life. Information theory is fundamental to the way the all those electronic gizmos (from the telephone to the computer and the microwave) we have got so used having loitering around the place. The fundamental principles of information theory are what govern the way the information is communicated, both within a electronic system (e.g., signals between the CPU and graphics card in your computer), and between them (e.g., telephone signals). While subtle nuances in the theory allows this information to be transferred faster and more efficiently, therefore making your computer or tv work faster and better.

At the core of this is something called Sampling Theorem; i.e., the Nyquist-Shannon Theorem. This basically covers the way analogue signals are translated into digital ones (and vice versa). This is easiest explained if we consider an example, say music. Lets consider we're sat in a quiet room strumming a guitar. The sound produced by the guitar spreads out through the room as a series of pressure waves. If we were to think about how these pressure waves are heard by a human ear, we would get a continuous line of varying amplitude; an analogue signal (see figure below).

However, if we want to record this sound so we can replay it on a computer we have to digitize it. Computers can't store analogue signals since they, by definition, have an infinite number of amplitude values. Thus, analogue signals are digitized, which means we describe the analogue signal as a series of amplitude values (see figure above). Thus, the sound of the guitar becomes a series of numbers that represent the amplitude of the sound (pressure wave) at a moment in time.

This digitization of the analogue signal is where the sampling theorem comes in. We have all got music stored on our computers which we can listen to. In order for this to sound the same as if were were sat in the same room as the real instruments playing, the sound has to be sampled at short enough time steps so as to convince the human ear that it is not a series of descrete samples. Basically, it's the same way as animations work. An animation consists on c. 30 individual drawings which are flashed onto the screen every second. The human eye can't tell the difference between them, and so is tricked into thinking it is a moving picture. With the digitization of the sound from our guitar, we're doing exactly the same process.

Every electrical gadget in your home works with these digital signals. What the Nyquist-Shannon Theorem describes, is the minimum time step at which a signal has to be sampled in order to convey a certain set of information. Engineers, mathematicians, and Physicists think of this information in terms of it's frequency, which is what the theorem describes; the Nyquist Frequency.

I deal with the Nyquist theorem pretty much every day as it also plays a fundamental part in signal processing, which is essentially what I do. However, what I didn't know was just how successful Nyquist and his colleagues at AT&T Bell Labs who pioneered information theory (amongst other things) were. The total of 11 researchers won 6 Nobel prizes between them! That is an incredible success rate, and probably one which will never be replicated anywhere else. Kinda puts into perspective everything us little people are struggling with!