VOA慢速英語：澳大利亞研發(fā)新科技限制涂鴉

Cities throughout the world spend a lot of money fighting graffiti. Graffitiwriters leave their mark in public places, often on walls or other surfaces.They spray paint words, artwork or other things on buildings, trains andbuses. Some graffiti writers even damage statues. Efforts by police to stopthe writers often fail.

Chemical-Sniffing Technology Fights Australia's Graffiti Vandals

Officials in Australia have begun using a new technology that can recognizethe most commonly used graffiti materials: paint and marker pens. They hopeit will help police stop people from defacing walls on the passenger areas oftrains.

Some passenger trains in Sydney, Australia are covered in graffiti.Surveillance cameras help police officers stop those who illegally write ontrain cars. But there are just too many cars in the system. Police and railroadofficials cannot watch all of the cameras all the time.

Last year, Sydney Trains -- the operator of the city’s rail service -- began usinga new surveillance system that has an “electronic nose.” Howard Collins is the head of Sydney Trains.

“We’ve had 50 people being charged with offenses. And as we roll it outnow to other trains, it’s proving even more successful.”

The device is called “Mousetrap.” It was developed by Technique Risk, anAustralian company. Mousetrap can identify gases released by markers andspray paints.

Mark Byers founded the company. He says when the device recognizes thesmell of graffiti, it sends a message to an alarm, which is connected to anearby surveillance camera.

“The strength of the system is the fact that security personnel or police canmonitor the system in the field with a mobile phone. The information theyreceive is the train or carriage number, the location that the event isoccurring and also where that train is going to.”

Graffiti writers cannot disable the system because the sensor is hidden in thewall of the train car.

Police guard the trains and train stations. Many of the officers look likepassengers. They can quickly react when Mousetrap tells them someone ispainting on the walls.

Howard Collins says the system keeps a record of where and when graffitiwriters are working. He says this can help officials decide where to deployofficers.

“Now we’re building a profile of where or when these incidents occur. So thepolice already have the intelligence and the information to say ‘this is wherethis is likely to occur’ and ‘this is the time of day.’”

Mr. Collins says Mousetrap has worked so well that most of Sydney’s trainsare now free of graffiti. He says it cost about $500,000 to put the system inplace. But he says that is not a lot of money compared to the $34 millionSydney Trains spent last year to remove graffiti.

I’m Bob Doughty.

VOA’s George Putic reported this story from Washington. Christopher Jones-Cruise adapted it into Learning English. George Grow was the editor.

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Words in This Story

graffiti – n. pictures or words painted or drawn on a wall, building or vehicle

spray paint – n. paint flying in small droplets or particles

defacing –v. to ruin the surface of (something)

surveillance camera – n. a camera designed to watch someone orsomething in order to prevent or identify a crime

offense – n. a criminal act

roll it out– idiom add to; place it on other; complete the launch of

monitor– v. to watch, observe or listen to something for a special purposeover a period of time

carriage– n. a train car

occurring – v. happening

profile– n. a description that provides information about someone orsomething