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Smart meter vulnerabilities

In response to James Bunyan’s letter in the June issue of E&T, the security threat arising from switches in smart meters could be significant and is well presented by Professor Ross Anderson in a paper, ‘Who Controls the Off Switch?’, which can be found on the Internet.

Professor Anderson points out some of the issues that could arise if significant populations of meters were attacked or malfunctioned and switched off power to large numbers of homes, it being physically impossible to reconnect them in a short space of time should they need to be replaced.

Other countries in Europe have recognised this issue and are reviewing the requirements for smart meters to be fitted with switches/valves given that such meters now form part of their critical national infrastructure and are exposed to a whole new set of risks ranging from accidental to malicious. Demand-response/load-control applications can be achieved through use of smart appliances or load-control switches rather than switching off the whole house as proposed in the UK.

John Cowburn CEng FIEE

Director, Smart Energy Networks

Fly or cruise?

Can I put the environmental claims of Tony James’s article on the cruise ship Allure of the Seas (‘Floating Cities’, April 2012) in perspective? The 6,360 passengers are in a 225,000t ship – 35t of ship per passenger – with power plants totalling 97MW or 15kW per passenger.

Fuel consumption per passenger mile works out at about three times higher than an Airbus A380, although of course the ship is not just about getting from A to B. It produces enough electricity to power 41,000 homes, which is 10 to 15 times more electricity per passenger than they would use in their own homes. So if you care about your carbon footprint, it’s much better to fly somewhere and stay in a hotel than to take your hotel with you.

Dr Richard Riggs MIET

Abingdon, Oxfordshire

An ethical algorithm

Like AR Samnakay (Letters, May 2012) I was quite surprised that the article in your March 2012 issue on a possible ethical code for engineers made no mention of the defence industry or weapons development.

As he says, it affects nearly all aspects of human society, but that leaves us with correspondingly complex issues to be resolved. Where is the guidance to come from? Are we all to be moral philosophers?

Probably, the answer is yes. We have to think things out for ourselves in the light of the moral standards applied across the rest of our lives and society. So how do we deal with a complex problem that has to be solved repeatedly for different input data? That’s an algorithm. That’s an engineering technique. In fact, that’s the way for engineers to contribute to how everyone else solves the problems.

An example of the power of this technique is the Nuclear Morality Flowchart project (, which is designed to enable people to resolve for themselves the ethics of nuclear deterrence. This fairly complex issue is resolved into a number of questions presented as a network. Each question tests certain data (the input being from an individual’s own considered opinion) and directs to the next appropriate question. The outcome is a decision tree – visually accessible, accountable and completely transparent.

Martin Birdseye MIET


Computer memories

Paul Gannon’s interesting article in the June 2012 issue of E&T on computing in 1952 states: “The [APEC] machine deployed the first magnetic rotating drum memory technology.” About two years earlier, in September 1950, I was a new undergraduate in Professor Fred Williams’ department at Manchester University and, quite soon after starting, my intake was shown around his computer laboratory by the Professor and Tom Kilburn.

We were shown a computer under development which had ‘Williams CRT fast memories’ and, I am sure, such a drum memory. The machine may have been ‘Baby’, but is more likely, I think, to have been a prototype for the Ferranti Mark I.

At that time, of course, this was cutting-edge technology and, 60-odd years later, I amuse myself occasionally by comparing that situation with the comparative power of my home installation of two PCs, a laptop and a Blackberry.

John Hopkins CEng MIET

Goostrey, Cheshire.

Look up

Your report on driverless trains (June 2012) points out the advantage of automating metro lines. However, although this applies to traditional lines in developed countries, there are many applications where the best approach would be to move in the other direction, with minimal, if any, signalling and with control entirely by the driver. Trams are such a system which have been in popular use for many years.

A development might be to use modified buses to run on dedicated overhead tracks. Because of the relative lightness of the vehicles this would be much cheaper to build and maintain than a railway, and although the carrying capacity is much less there are many less busy routes and routes in poorer countries where such a system would be of great use in avoiding congested roads.

Ray Cantrell MIET


Blumlein & Co

May I echo Colin Warner’s comments on the genius of Alan Blumlein (Letters, June 2012). Although many people would not know his name or anything about his life, he was familiar to me through the interest of my father, who spent nearly all of his working life associated with radar research, having been posted to Bawdsey Manor in his teens.

Much later I discovered that a neighbour of mine was Blumlein’s nephew by marriage and this led to an introduction to Alan’s two sons, Simon and David, both of whom were good enough to attend a presentation my 90-year-old father made on the birth of radar to our local IET section.

The following year Simon gave us a presentation on his father’s life and work. So as far as I am concerned, Alan Blumlein is up there with the great engineers, despite his premature death.

Readers may be interested to know that a memorial window in Goodrich Castle (close to the site of the fatal crash) was unveiled on 7 June 1992 to mark the 50th anniversary of the accident. It is dedicated to the memory of all service and civilian aircrews who lost their lives in radar development flying duties.

David Tandy CEng MIET

Chairman, IET West London Section

Colin Warner’s letter about the life of Alan Blumlein makes brief mention of John Logie Baird and his role in the invention of television.

I have long held the view that the contribution of Baird to the invention of television was minimal in all respects. The Baird electromechanical system was crude and, in many ways, only an extension of the then existing scanning system used to transmit documents over landlines.

There is no doubt that Baird was possessed of considerable personal charm and, as an excellent communicator, projected a very good image which allowed him to attain a prominent level of recognition.

The true inventors of television were the EMI team lead by Sir Issac Shoenberg. Originally from Russia, Shoenberg joined the Marconi Company in 1914 and became head of research at the newly formed EMI in 1931.

Between 1932 and 1936 he persuaded EMI to invest heavily in high-definition, all-electronic television. Included in the vast array of inventions are the Emitron camera, the distributed amplifier used in the first Alexandra Palace transmitter modulator, and numerous specialised circuits to deal with television waveforms.

Despite all of this, Shoenberg and the EMI team have never been afforded an appropriate level of recognition in the field of television development. They were also involved, albeit belatedly, in the development of World War Two electronics systems, which included H2S radar and infra-red image convertors.

Geoffrey H Robinson CEng FIEE FIET

St Andrews

Faulty fuses

Reading your May 2012 issue and the article on the hidden risks of counterfeit cables, I was reminded of some car fuses I purchased online from Amazon in April 2011.

On inspection the fuse thicknesses seemed to be nearly identical except the 30A, with the lower values thicker than the 30A fuses. This concerned me, so working in a university electrical engineering school I set about testing the fuses. Of the values tested (5A/10A/15A/20A/25A/30A), only the 30A fuse blew at the correct rating. All the others happily melted their plastic casings but did not blow even at 30A!

I contacted Amazon about this worrying result – they just gave me a refund and would not entertain a recall that I suggested. The product is still on sale.

Dr Ian Clark MIET

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