Let's imagine for the moment that you own a large
department store, and you are having a big problem with
shoplifting. (You're not alone -- retail stores lost $26
billion last year to shoplifting!) What are you going to do?
You cannot let it continue, because every month your
accounting system tells you that you are losing thousands of
dollars to theft. It forces you to raise your prices, and that
means you have to charge more than the store next door. That
can make it very hard to compete, especially if the store next
door is successfully discouraging shoplifting.
As a retailer focusing on the problem of what's known in
the industry as loss prevention, you basically have
three methods at your disposal to slow the shoplifters down:
(1) You can watch everyone in the store like a hawk and make
sure they don't steal anything. You can do that using security
guards and/or video survelliance systems; (2) You can make
things hard to remove from the store by bolting them down,
attaching cables, putting things in display cases and behind
the counter; (3) You can use a system that attaches special
tags onto everything so that an alarm goes off whenever
a shoplifter tries to walk out with an item. In this edition
of How
Stuff Works, we'll look at each of these options in
more detail.
How Does Video Surveillance
Work?
Our first option involves the use of
deterrents such as security guards, observation mirrors (that
allow store clerks to see throughout the store) and
closed-circuit television (CCTV) surveillance systems.
Most large stores use some combination of these techniques,
which were among the earliest tools used to combat
shoplifting. Smaller businesses, unable to afford security
guards, were able to install videocameras -- usually in a
prominent place so that shoppers knew they were being watched
-- to record activity in the store. Later, the retailer could
review the tapes on a VCR, observe shoppers behaving
suspiciously (sometimes even stealing) and note the vulnerable
displays or areas in the store. The problem with this
record-and-review system is that some shoplifters get away
with stealing. On the other hand, experts say, the system has
merit in that it allows for possible recognition of repeat
offenders (something that is prevalent among shoplifters). By
reviewing these tapes, the store owner can also learn about
theft patterns and get ideas about ways to deal with them.
Your imaginary department store would probably use
electronic surveillance a bit differently than smaller
businesses. You might have security staff monitoring store
activity on closed-circuit TV as it happens in an effort to
prevent shoplifting. Today, there are even systems that allow
retailers with several locations to monitor stores and
distribution centers from a single location. These remote
surveillance systems allow users to send full-frame video
image streams over high-speed phone lines to other locations
and to electronically store digital video images for review or
evidence.
And in larger stores, cameras are often less visible. Next
time you're in your favorite department store, look around.
High-speed, high-resolution digital cameras may be mounted in
smoke detectors, sprinkler heads, thermostats or clocks. (It's
popular to mount cameras in ceiling tile domes (they're
bubble-like and tinted so no one can see where the camera is
pointed). From this vantage point, a pan/tilt/zoom
camera can swing about and follow someone around the store.
(If security is not monitoring and operating the camera, it
can be set up to pan automatically but will not follow someone
around the store.)
Video cameras used for security purposes don't look
anything like the video camera your family has at home --
they're becoming smaller and more specialized. A standard
surveillance camera might be in the neighborhood of 4 inches
long by 2 1/2 inches wide with a lens on the end, according to
Jeff Bates of ADT
Security Systems in Raleigh, N.C. A hidden camera might be
a board camera, which basically is a 1 inch by 1 inch
square computer board with a tiny lens, perhaps 1/4 inch in
size. These cameras are designed to two specifications,
experts say: they must be small and easy to hide.
Is Anchoring the Merchandise in
Place a Good Idea?
Now for option number two:
locking things up nice and tight. Cable, wire products and
security bars, like those manufactured by Se-Kure
Controls (Canada) Inc., are also familiar types of retail
security devices. They certainly work to keep your merchandise
in the store! But retail industry experts say this isn't the
best way to move your products because cables and other
locking devices make it difficult for people to examine items
and try on garments. Customers have to get a clerk to come
release the item so they can try it on or look at it. Since
most people are in a hurry, this might motivate shoppers to
move on to a store where the merchandise is more accessible.
Having said that, if you need to use security cables and
locking racks, there's a wide variety of products available to
you. Security cables are made with a variety of properties:
coaxial cables (for CCTV systems), alarm cables and fiberoptic
cables. Wire lanyards, which can be snaked through a
garment to attach it to a rack or display, are being made
stronger all the time. For example, Retail
Security Products offers to send potential customers a
lanyard test kit to illustrate the strength -- over 250 pounds
in a pull test -- of their product. You've probably also seen
the locked steel racks used for expensive coats and jackets --
again, these have to be unlocked by a sales clerk.
How Do Tag and Alarm Systems
Work?
Security experts say the most effective
anti-shoplifting tools these days are CCTV and the
tag-and-alarm systems, better known as electronic article
surveillance (EAS) systems. Separately, these are good
options. Used together, experts say, they're almost
unbeatable. EAS is a technology used to identify articles as
they pass through a gated area in a store. This identification
is used to alert someone that unauthorized removal of items is
being attempted. According to the Association
of Automated Identification Manufacturers, over 800,000
EAS systems have been installed worldwide, primarily in the
retail arena. EAS systems are useful anywhere there is an
opportunity for theft of items of any size. Using an EAS
system enables the retailer to display popular items on the
floor, where they can be seen, rather than putting them in
locked cases or behind the counter.
Loss prevention expert Robert
L. DiLonardo, says new EAS technologies are being produced
-- not only to reduce shoplifting -- but also to help increase
sales, lower labor costs, speed inventory, improve stockroom
logistics and, one day, to replace inventory record-keeping.
But for now, we'll stick to the role of EAS in battling
shoplifting in your imaginary store!
Three types of EAS systems dominate the retail industry. In
each case, an EAS tag or label is attached to an item. The tag
is then deactivated, or taken from an active state
where it will alarm an EAS system to an inactive state where
it will not flag the alarm. If the tag is a hard, reusable
tag, a detacher is used to remove it when a customer purchases
the item it's attached to. If it's a disposable, paper tag, it
can be deactivated by swiping it over a pad or with a handheld
scanner that "tells" the tag it's been authorized to leave the
store. If the item has not been deactivated or detached by the
clerk, when it is carried through the gates, an alarm will
sound.
The use of EAS systems does not completely eliminate
shoplifting. However, experts say, theft can be reduced by 60
percent or more when a reliable system is used. Even when a
shoplifter manages to leave the store with a tagged item, the
tag still must be removed -- something that is no longer as
easy as it once was. For example, some EAS tags contain
special ink capsules, which will damage the stolen item when
forcibly, and illegally, removed. (This type of device is
known in the industry as benefit denial -- we'll
discuss it more later!). Other popular EAS components today
include source tagging, whereby an inexpensive label is
integrated into the product or its packaging by the
manufacturer.
The type of EAS system dictates how wide the exit/entrance
aisle may be, and the physics of a particular EAS tag and
technology determines which frequency range is used to create
a surveillance area. EAS systems range from very low
frequencies through the radio frequency range (see How
Radio Scanners Work). These EAS systems operate on
different principles, are not compatible and have specific
benefits and disadvantages. (That's why the Consumer
Products Manufacturers Association, Inc. is encouraging a
"tower-centric" EAS approach that can "read" multiple tag
technologies rather than the "tag-centric" models that exist
today.)
How Do Radio Frequency EAS Systems
Work?
Radio Frequency (RF) Systems are the
most widely used systems in the United States today and RF
tags and labels are getting smaller all the time. As you can
see in the drawing at the right, the RF EAS system works like
this: A label -- basically a miniature, disposable
electronic circuit and antenna -- attached to a
product responds to a specific frequency emitted by a
transmitter antenna (usually one pedestal of the entry/exit
gate). The response from the label is then picked up by an
adjacent receiver antenna (the other pedestal). This processes
the label response signal and will trigger an alarm when it
matches specific criteria. The distance between the two gates,
or pedestals, can be up to 80 inches wide. Operating
frequencies for RF systems generally range from 2 to 10 MHz
(millions of cycles per second); this has become standard in
many countries. Most of the time, RF systems use a
frequency sweep technique in order to deal with
different label frequencies.
Sometimes both the transmitter and receiver are combined in
one antenna frame -- these are called mono systems and
they can apply pulse or continuous sweep techniques or a
combination of both. According to Tag
Point Ltd. experts, mono systems could be effective for
you if your store's entry is small. The mono system is used
with hard labels, which are slightly more expensive than paper
labels used with RF sweep techniques.
Sensors (gates/pedestals) made by Checkpoint
Systems, one of the largest manufacturers of EAS products,
emit a low-energy RF pulse, which "listens" for the tag. This
technology, known as digital signal processing,
actually "learns" about its surroundings so that it can
accurately distinguish between the tag signal and extraneous
noise. Store employees love this because it virtually
eliminates false alarms! (Store owners often ask why there are
no invisible sensors. Cross Point experts
say it is technically possible to create an invisible system
by, for example, installing an antenna loop around a store's
door. However, tests have shown that the preventive value of a
visible system is greater and results in decreased theft.)
This tag is about 1.5 inches (3 cm) square.
On the other side is an innocuous
paper label that says,
"Thank you for shopping with us!"
There are many different ways to implement an RF system
(see this
patent and the patents it references for one type of
implementation). The basic idea is that the tag has a helical
antenna etched from thin aluminum bonded to a piece of paper.
At the end of the antenna is a small diode or RC network that
causes the tag to emit a radio signal in response to the radio
signal it receives. To disarm the tag, a strong RF pulse (much
stronger than the gates emit) blasts the tag and burns out the
diode or RC components. Between the gates a burned out tag
does not emit a signal, so the gates let it pass without an
alarm.
How Does An Electromagnetic System
Work?
The Electromagnetic (EM) system, which
is dominant in Europe, is used by many retail chain stores,
supermarkets and libraries around the world. In this
technology, a magnetic, iron-containing strip with an adhesive
layer is attached to the merchandise. This strip is not
removed at checkout -- it's simply deactivated by a scanner
that uses a specific highly intense magnetic field. (One of
the advantages of the EM strip is that it can be re-activated
and used at a low cost.)
What most people refer to as an electromagnetic tag is
actually a metal wire or ribbon that has high
permeability, making it easy for magnetic signals to
flow through it, according to Sensormatic's EAS Product Co.
CTO Hap Patterson. "When we drive the tag, flux is being
allowed to flow through the tag until it's saturated," he
says. "When it's saturated, from a magnetic perspective, it
begins to look like air. Saturation occurs abruptly and is an
important part of the design of the tag."
Look at the figure showing the EM system with its receive
coil and transmitter on either side and tag in the middle.
When the tag goes from active to saturated, the receiver
detects the change in the amount of the signal picked up from
the transmitter. "If you look at the receiver signal, you'll
see a bump when saturation occurs," Patterson says. Saturation
occurs twice each cycle-once on the transmitter's positive
cycle and once on its negative cycle. What is happening is the
system is checking for the special material used to make the
tag. (In scientific terms, the permeability of steel is much
lower than the metal used to make the tag. In addition, when
steel goes to saturation, it tends to do so slowly, not
abruptly. So the EM system uses these differences to
differentiate between a still-active tagged item leaving the
store and a wrench in someone's pocket.)
A magnetized piece of semi-hard magnetic material
(basically, a weak magnet) is put up next to the active
material to deactivate it. When you magnetize the semi-hard
material, it saturates the tag and puts it in its inactive
saturated state.
That same kind of tag is often used in the library, where
it can be reactivated by demagnetizing the semi-hard magnetic
material.
The EM system works by applying intensive low frequency
magnetic fields generated by the transmitter antenna. When the
strip passes through the gate, it will transmit a unique
frequency pattern. This pattern is, in turn, being picked up
by an adjacent receiver antenna. The small signal is processed
and will trigger the alarm when the specific pattern is
recognized. Because of the weak response of the strip and the
low frequency (typically between 70 Hz and 1 kHz) and
intensive field required by the EM system, EM antennas are
larger than those used by most other EAS systems, and the
maximum distance between entry pedestals is 40 inches. Also,
because of the low frequency here, the strips can be directly
attached to metal surfaces. That's why EM systems are popular
with hardware, book and record stores. (Check out the patent
for more details!)
What's the Third Type of EAS System
Used Most Often?
The newer acousto-magnetic
system, which has the ability to protect wide exits and
allows for high-speed label application, uses a transmitter to
create a surveillance area where tags and labels are detected.
The transmitter sends a radio frequency signal (of about 58
kHz) in pulses, which energize a tag in the surveillance zone.
When the pulse ends, the tag responds, emitting a single
frequency signal like a tuning fork. While the transmitter is
off between pulses, the tag signal is detected by a receiver.
A microcomputer checks the tag signal detected by the receiver
to ensure it is at the right frequency, is time-synchronized
to the transmitter, at the proper level and at the correct
repetition rate. If all these criteria are met, the alarm
occurs.
A typical AM tag from Wal-Mart
AM material is highly magnetostrictive, which means
that when you put the tag material in a magnetic field, it
physically shrinks. The higher the magnetic field strength the
smaller the metal becomes. The metal actually shrinks about
one-thousandth of an inch over its full 1.50 inch length.
As a result of driving the tag with a magnetic field, the
tag is physically getting smaller and larger. So if it is
driven at a mechanically resonant frequency, it works like a
tuning fork, absorbing energy and beginning to ring.
This tag also requires bias magnet material in
addition to active element material. The active material will
shrink no matter which direction the magnetic field is placed
upon it. If the tag is driven with Frequency, F, it gets
smaller as the magnetic field increases and larger as it's
driven towards zero. This means that while it is being driven
at F, the tag is trying to work at 2F, because at both
positive and negative halves of the drive signal, the tag is
getting smaller. To get the tag to work at F, a bias field is
required. The bias is provided by a semi-hard magnetic element
in the label. When magnetized, the bias prevents the active
element from ever being in a zero field condition. So for an
entire half of the drive signal, the tag shrinks. Then it
expands for the other half. This results in an F response.
When you walk through the gate with a tag, the transmitter
in the gate energizes the material and causes it to resonate
at F. The transmitter then stops. The tag will continue to
"ring" at F for a short period of time, and the receiver
listens for that frequency. If it hears it, it knows there is
a tag and sounds the alarm.
When the AM tag is demagnetized, it is deactivated. When
it's magnetized, it is activated. (This is the opposite of how
the deactivation of EM tags works.)
(Home
Depot began using acousto-magnetic tags from Sensormatic
Electronics Corp. because the tags work well when they're
close to metal and the stores use metal shopping carts -- not
all systems work well with metal objects.) For more detail on
this system, check the patent!
Other EAS technologies include the microwave system,
one of the oldest anti-shoplifting systems and judged by
experts to be only about 80 percent accurate, is still around
in some stores. Security experts also caution retailers that
this system is not compatible with increasingly popular source
tagging options. (We'll discuss source tagging more later!)
What Other Devices and Components
Are Used with the EAS Systems?
In addition to the
all-important gates or pedestals you walk through, the most
important components of EAS systems include the following:
Paper tags like these are
disposable and
widely used with
radio frequency systems.
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- Disposable tags -- Disposable paper tags and
labels are available in many different types --
pressure-sensitive labels with simulated bar codes, tags or
labels that can be imprinted with price, inventory,
promotional or bar-code information, and tags specially
designed for products such as earrings, compact discs and
cosmetics, which are all items easily pocketed by
shoplifters. These thin, adhesive-backed labels can be as
small as a paper clip and can be easily disguised to look
like standard retail tags. Most importantly, the radio
frequency tags, unlike tags connected to some
electromagnetic sensors, can't be disrupted by common
magnets.
You'll find these
reusable tags
on most
apparel. |
- Reusable tags -- Probably the most familiar
reusable tag is the hard, plastic tag (known as an
alligator) attached to most apparel and armed with an almost
impossible to defeat locking mechanism -- it can also be a
pain if it's attached to the wrong part of a garment you
want to try on! This off-white, pin-connected tag requires a
special detacher unit to remove it. (If you've ever had a
clerk accidentally leave one of these on your purchase --
sometimes a tag buried in a bag-full of stuff can go through
the sensor without detection, store clerks say -- you know
that you cannot get that thing off at home! Some department
stores offer a terrific, public relations service: if their
clerk fails to remove this tag from your purchase, the store
will send someone to your home with a removal device. This
means you can wear that new dress to the event you bought it
for!) Other reusable tags you might have seen include
plastic devices without pins (they use a foam rubber pad!
and abrasive strip to grip garment firmly without causing
damage), lightweight colored tags encased in clear plastic,
flexible tags printed with a simulated bar code, and fluid
tags.
- Benefit denial tags -- This is a fluid tag. If
you steal an item with this kind of tag, you're going to get
an unpleasant surprise when you try to remove it in the
dressing room or later at home. The ingenious tags have been
designed to break and release fluid -- usually colored
indelible inks -- onto the garment (working even against
gravity) and on you if you try to forcibly remove it. The
idea is that a shoplifter is being denied any benefit from
his/her crime and will not be able to use or sell the item
because it has now been ruined.
Store clerks use
electronic
scanners to deactivate tags
on your
purchase.
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- Deactivators and detachers -- Desirable qualities
in deactivators include a large deactivation zone and 100
percent deactivation with no false alarms. The type of
electronic deactivator depends upon the kind of EAS system
and tags used by the store. We're all familiar with
hand-held scanners and flat scanner pads used to
swipe and deactivate merchandise tags. Traditionally,
scanners must touch a label directly to use specific
frequency to deactivate it. But with the growing use of
source tagging (hiding identification tags somewhere on an
item or in its packaging) proximity deactivators, or
verifiers that don't require contact with a label, are
becoming more important. There are also mass or bulk
deactivators, which bring EAS labels from an inactive state
to an active state while the products are still packaged in
master cartons or cases. A plus of state-of-the-art
deactivation devices is that they can be integrated into all
of the commercially available bar code scanners. (See How UPC Bar
Codes Work) so that clerks are scanning the product code
at the same time they're deactivating the security circuit.
(See this patent
for more information on how a deactivator works.) To remove
most hard tags, a detacher/releaser is necessary.
Today's detachers, which basically unlock the tags, are
designed so that they cannot be copied or purchased by
shoplifters. Some detachers are hand-held; others are fixed
-- most are simple devices with no moving parts, something
that makes them very durable.
- Radio frequency identification (RFID) -- RFID is
used in a variety of ways today, including automating toll
collection and decreasing time at the gas pump. RF
technology experts say RFID is the way of the future in the
retail security arena as soon as the application software is
in place. Checkpoint Systems has collaborated with
Mitsubishi Materials Corp. to develop RF intelligent
tagging, which combines an integrated circuit with an RF
antenna to deliver a tag capable of simultaneously storing
and processing information about a product while protecting
the product from theft. (It can even identify a shoplifter
who comes back in wearing a stolen item, since only the
security portion of the tag is turned off when an item is
purchased. The RFID tag is always on!) Researchers say this
technology could someday mean that we don't have to unload
our grocery carts for checkout -- the system could gather
the information it needs from each item while it remains in
the! shopping cart!
- Accessories and other products -- In addition to
selling hundreds of different types of labels, label
applicators, security pins, locking devices for ink tags and
security lanyards for use with EAS systems, some companies
even offer "dummy" or inactive EAS tags and systems. Retail
Security Products claims these tags and labels can be used
as stand-alone deterrents to theft, with inactive EAS
pedestals or in conjunction with a live EAS system on lower
priced items. (They sold over 20 million of the dummy tags
-- at 1/3 cents each -- to retailers across the United
States last year, they say.) Other manufacturers and experts
warn that dummy labels, if used, should be easily
distinguishable only to shop personnel.
What Is Source Tagging All
About?
As its name implies, source tagging is the
embedding of disposable RF security labels at either the point
of manufacture or packaging. Source tagging has been highly
successful in the packaged products industry, and retailers,
such as discount giant Target,
are starting to use it for merchandise such as earrings,
apparel, shoes, batteries, videocassettes, audiotapes,
computer software, sporting goods and electronics. (Retailers'
interest in source tagging has increased as shoplifters have
gotten around anti-shoplifting tags applied to the outside of
packages by removing the product and leaving the empty box on
the shelf!)
The newest source tags are paper-thin and easily integrated
into automated production processes. These tags are applied in
primary packaging (or within or on the product itself -- for
example, incorporated into woven garment tags) and under
labels on bottles. Checkpoint experts say their
two-dimensional source tags can be invisibly embedded between
layers of thin paper stock or cardboard on standard blister
packages. These invisible tags, which are deactivated by the
clerk with a verifier that needs no physical contact with the
tag to work, are especially effective at addressing employee
theft and represent a hot topic in retail security today.
Sensormatic Products says its tiny Ultra-Strip can be
detected through foil, liquids or layers of packaging. (Some
industry
consultants question the future of source tagging in
retail apparel in light of the large number of existing
microwave EAS systems -- systems that some consider obsolete
and that cannot be adapted to incorporate low-cost source
tagging in the future. There are also questions about how best
to incorporate source tagging without losing the tag's
inherent value as a theft deterrent.)
How Much Does An EAS System Cost?
And I've Heard They Can Be Dangerous for People Wearing
Internal Medical Devices -- Is That True?
Experts
say there are large differences in cost depending on the
system, the size of the store and the amount of merchandise to
be protected. By using state-of-the-art equipment such as
digital signal processing and customized locks that can't be
released by common detachers, theft can be reduced by about 60
percent. Considering that store personnel will have more time
for assisting shoppers (instead of watching for potential
thieves), a reliable EAS system can pay for itself in 1 1/2 to
2 years.
You may have heard news accounts a couple of years ago of
research that claimed entry/exit sensors could be harmful to
people wearing internal medical devices such as pacemakers and
defibrillators. The
U.S. Food and Drug Administration acknowledges that
internal medical devices might be slightly affected by some
EAS systems. However, officials there don't consider this a
public health problem. Many Americans were alarmed when the
Heart Institute of St. Petersburg, Fla., released results of a
two-year study of EAS systems and their possible effects on
people wearing pacemakers and defibrillators. Researchers said
they found that the electromagnetic fields of anti-shoplifting
systems can interfere with cardiac devices if users linger in
the magnetic zone between the pedestals or gates. Soon after,
the FDA announced that, of the 1 million Americans with
internal medical devices such as pacemakers, there had been
only 44 reported reactions over the past 10 years related to
anti-theft system magnetic fields. Heart Institute researchers
encourage people with internal medical devices to avoid any
potential problems by moving quickly through these systems as
well as metal detectors.
Now that you know more about the kinds of anti-shoplifting
devices being used in stores, take a look at this article on
reducing shrinkage (an industry term for lost merchandise) by
Roger
Schmedlen for some additional ideas about security in your
imaginary -- or real -- department store.
And if you're someone who needs help conquering a pattern
of shoplifting, please contact Shoplifters
Anonymous. They can help!
Lots More Information!
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