Electronic article surveillance

Electronic article surveillance (EAS) is a type of system used to prevent shoplifting[1] from retail stores, pilferage of books from libraries, or unwanted removal of properties from office buildings.There are site conditions and other parameters which enable them to be installed, but often malls insist on concealed system as a mandate to improve the shopping experience.A further application is the intellectual property (IP) protection against theft: Security paper with embedded microwires, which is used to detect confidential documents if they are removed from a building.[3][4] Amorphous metals are used in such systems due to their good magnetoelastic coupling, which implies that they can efficiently convert magnetic energy into mechanical vibrations.This is often the reason why people trigger an alarm entering a store, which can cause great frustration for both customers and staff.The occasional shoplifter, not being familiar with these systems and their mode of operation, will either get caught by them, or preferably, will be dissuaded from attempting any theft in the first place.These are typically large paper bags that have been lined with multiple layers of aluminium foil to effectively shield the RF label from detection, much like a Faraday cage.A similar situation would be the loss of signal that a cell phone suffers inside an elevator: The electro-magnetic, or radio waves are effectively blocked, reducing the ability to send or receive information.This is of particular application in everyday items that consumers might carry on their person to avoid the inconvenience of potentially live reactivated EAS tags when walking in and out of retail stores.The possession of shoplifting tools (e.g. lined bags or wire cutters to cut bottle tags) can lead to the suspect being arrested for suspicion of theft or "Going equipped for stealing, etc."[9] In summary, while even the least expensive EAS systems will catch most occasional shoplifters, a broader range of measures are still required for an effective response that can protect profits without impeding sales.The local alarm continues to sound for several minutes after leaving the store, attracting attention to the shopper carrying the merchandise.[11] A single EAS detector, suitable for a small shop, is accessible to all retail stores, and should form a part of any coherent loss or profit protection system.With increasing prevalence, stores have metal detectors at the entrance that can warn against the presence of booster bags or detachers.[citation needed] Most systems can be circumvented by placing the tagged goods in a bag lined with aluminum foil.[9][14] In any case, possession of such a bag demonstrates a prior-intent to commit a crime, which in many jurisdictions raises shoplifting from misdemeanor to felony status, because they are considered a "burglary tool.Like most systems that rely on transmission of electromagnetic signals through a hostile medium, EAS sensors can be rendered inoperative by jamming.Evidently, shoplifters will not feel the need to follow radio transmission regulations; hence crude, easy-to-build transmitters will be adequate for them.However, due to their high frequency of operation, building a jammer can be difficult for microwave circuits; these systems are therefore less likely to be jammed.Radio-frequency systems tend to be the least interfering because of their lower power and operating frequency in the MHz range, making it easy to shield against them.A March 2007 study by the Mayo Clinic in Rochester, Minnesota, reported instances where acousto-magnetic EAS systems located at the front of retail stores caused a pacemaker to fail and a defibrillator to trigger, shocking the persons in which they were implanted.