Barely a day goes by without another report of illegal immigrants stowing away in transport destined for Britain. As those seeking entry to Britain become increasingly fed up of being held in limbo in France, they seek ever more inventive methods of securing their transport across the Channel. But is the situation as grave as the UK newspapers suggest and what is currently being done to protect Britain’s borders?
The main responsibility for stopping those wishing to enter the country illegally lies with the UK and French border security agencies. These agencies police the ports on both sides of the channel, monitoring the situation and stopping to check vehicles they deem suspect. Due to European laws, in addition to French controls the UK Border Agency has a presence in France as well as Britain and is entitled to carry out certain checks on inbound lorries. Together, they search vehicles using a series of different methods:
Passive millimetre wave imaging – this worksmuch like an x-ray machine, scanning the vehicle and highlighting different masses with different shades. Were a person hiding in behind packed boxes, they would be shown as a different shade on the scan.
Heartbeat detectors - these use probes attached at various points of the lorry’s body to detect any unusual movement taking place. Whilst typically not powerful enough to detect actual heartbeats, the probes should spot a person shifting around. However this method is not fault free as passing traffic has been known to affect the readings.
CO2 probes - when inserted into the vehicle these show up irregular levels of CO2, which would result from humans breathing out into the atmosphere of the container. Unfortunately depending on the cargo of the lorry in question CO2 probes might not be appropriate. Any paper or plant products for example will bias the reading.
Sniffer dogs – these are arguably the most effective detection method. Mainly used by the UK border force, these dogs are able to sniff out anyone hiding inside a cargo lorry but are expensive to use and can tire easily.
All the techniques above have clear strengths however all also have areas of weakness, which limit their effectiveness. Employed together the chance of success rises dramatically but the key is discerning how to mix the techniques in order to get the best results.
It is just this formula that my team and I at the Intelligent Modelling and Analysis Research Group (IMA) have been trying to discover. The IMA group has just finished a project at Calais Ferry port, using an agent-based computer simulation of the port to figure out the most successful way of simulating various scenarios and then utilising all the different techniques. With nearly 50 sailings a day, the Port of Calais is a central hub for traffic from France to Dover and the huge numbers of trucks which pass through each day are particular targets for those trying to enter the country illegally.
One of the key initial challenges for the team was discerning how complicated the simulation would have to be to provide valid results. Not only did the simulation have to be able to factor in the different techniques used but would also have to process and factor in the different patterns which can be found in traffic arrival and therefore illegal activity on any given time of day/day of the week or season. Once the simulation were complex enough to run these simulations the team then went through all the different detection tools systematically, testing them with rare events and scenarios to try and understand the limits of each.
Estimating the monetary cost of each scenario was also of vital importance so the team ran a range of different simulation models to assess and compare the different probabilistic methods of estimating costs between current policies. The idea was to use the results to enable the authorities to make an informed choice between the investments versus the benefits and costs for the business.
By implementing a range of these different and complex simulation methods, the IMA group was able to prove that employing different methods in different orders did indeed produce vastly diverse results, with differences being so significant that certain policies were clearly shown as better.
The team are now working with Calais to make the simulator even more realistic, whilst at the same time starting to talk to the authorities at Dover about developing a similar system.UWE AICKELIN
Uwe Aickelin is an IEEE Member, and Professor of Computer Science at The University of Nottingham and leader of the Intelligent Modelling & Analysis Research Group (IMA). IEEE, the world’s largest technical professional association, is dedicated to advancing technology for the benefit of humanity. Through its highly cited publications, conferences, technology standards, and professional and educational activities, IEEE is the trusted voice on a wide variety of areas ranging from aerospace systems, computers and telecommunications to biomedical engineering, electric power and consumer electronics.
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