Computer Applications (Speed Traps)

In the last ten years, police have installed speed trap units on many busy roads. These contain a radar set, a microprocessor and a camera equipped with a flash. The radar sends out a beam of radio waves at a frequency of 24 gigahertz. This is equivalent to a wavelength of 1.25 cms. If a car is moving towards the radar, the reflected signal will bounce back with a slightly smaller wavelength. If away from the radar, the waves will reflect with a slightly longer wavelength. The microprocessor within the unit measures the difference in wavelength between outgoing and returning signals and calculates the speed of each vehicle. If it is above the speed pre-set by the police, the camera takes a picture of the vehicle. The information is stored on a smart card for transfer to the police computer. The owner of the vehicle can then be traced using the Driver and Vehicle Licensing Centre database.

Some drivers have now got used to these traps. They slow down when they approach one to ensure that the camera is not triggered. They speed up again as soon as they have passed. This is known as ‘surfing’. One way of outwitting such motorists is a new computerized system. This consists of two units equipped with digital cameras positioned at a measured distance apart. The first unit records the time each vehicle passes it and identifies each vehicle by its number plates, using optical character recognition software. This information is relayed to the second unit which repeats the exercise. The microprocessor within the second unit then calculates the time taken by each vehicle to travel between the units. The registration numbers of these vehicles exceeding the speed limit are relayed to police headquarters where a computer matches each vehicle with the DVLC database. Using mailmerge a standard letter is then printed off addressed to the vehicle owner.

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How Do I Remove a Computer Virus?

Keep your antivirus program up-to-date. If you have already installed an antivirus program on your computer, it’s important that you keep it up-to-date. Because new viruses are being written all the time, most antivirus programs are updated frequently. Check your antivirus program’s documentation or visit their website to learn how to receive updates.

Stop a runaway virus. Viruses are sometimes created specifically to take control of your computer and send copies of themselves from your computer to other computers. You can usually tell this is happening if your computer is performing slowly and accessing the network more frequently than normal. If this happens, you should disconnect from the Internet and network (if you’re on one); run your antivirus software (from a disc or a software on your computer) to remove the virus.

Manually remove viruses. Sometimes a virus must be removed manually. This is often a technical process and should only be attempted by computer users who have experience with the Windows registry and who know how to view and delete system and program files in Windows.

The first step to identify the virus. Run your antivirus software to identify the name of the virus. If you don’t have an antivirus program, or if your program does not delete the virus, you can still identify the virus by looking for clues about how it behaves. Write down the text in any messages displayed by the virus or, if you received a virus in e-mail, write down the subject line or name of the file attached to the message. Search the antivirus vendor’s website for references to those specific things you wrote down to find the name of the virus and instructions how to remove it.

My virus is gone. Now what? Once a virus is removed, you might have to reinstall some software, or restore lost information. Doing regular backups can go a long way toward easing the pain of a virus attack. If you haven’t kept backups, start now.

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