Tuesday, 9 November 2010

Density of Information

Original Article - Technology Review
Watch Where You're Going
Businesses are quietly buying mobile-phone data to discover the paths that consumers take.
Target must make some people hungry, because a quarter of its shoppers head from the store to a restaurant. Another 25 percent or so eat out before their shopping trip. So maybe Target should capture some extra revenue by selling meals right on the premises. Or perhaps it could do a cross-promotion with neighboring food establishments.

Charting your path: This map shows a driving trace
from a hypothetical participant who volunteers to
share her mobile phone’s GPS data with Locately.
It shows her leaving her home in Princeton,
Massachusetts, to go shopping at the nearest
Wal-Mart. Credit: Locately
The numbers aren't guesses. Nor are they estimates based on customer surveys taken after the fact. They're actual measurements of where and when a sample of people spent their time, garnered by pinging the GPS receivers on their mobile phones. New services are popping up that track people in real time to give businesses a more detailed picture of consumer habits than ever before. The new tracking services go beyond location-based apps such as Foursquare, which require users to actively check in. Rather, these startups connect the dots of where you go without your doing anything at all.

In the past, this kind of location data could be obtained only by asking or paying consumers to fill out surveys. Even then, people might not remember exactly where they went after shopping at Target, or they might give the answers that they thought the questioner wanted to hear. They might not even know the answers to some questions, such as how often they were in range of a certain supermarket or whether they'd passed by any ATMs.

"Survey-based research is really great for figuring out what people think, but it misses out on where they go and what they do," says Thaddeus Fulford-Jones, CEO of Boston-based Locately, a startup in the new field of location analytics.

The information about Target shoppers comes from a pilot study Locately did with Mobext, the mobile-marketing arm of advertising agency Havas Digital. From Mobext's usual panels of shoppers who'd volunteered to offer opinions, it recruited people from Boston, New York, and Chicago who had cell phones with Sprint Nextel. The shoppers, who granted the company permission to follow their GPS traces for two weeks, didn't have to activate anything on their phones. Sprint's equipment would take a reading of their location every few minutes during the day and less frequently at night. If they were driving or walking from store to store, for instance, that information was transmitted to Locately.

Cell-phone companies have always been able to figure out roughly where callers are by triangulating among the nearest cell towers. Since 2003, the government has required more accurate locations in case people use their cell phones to call 911, so GPS was added to all phones. Carriers must provide the data to law enforcement in response to a subpoena. Last year, phone companies got a million such queries.

But now smart phones are loaded with apps that rely on users' willingness to have their phones reveal where they are. Which means this information is largely there for the taking. "It's not very hard to get to a tangible benefit," says Phuc Truong, managing director of Mobext. For instance, the measurements provide hard-to-get specifics on commuting times and routes. A company might use that information to increase its subway advertising or fine-tune the timing of a radio ad, then follow up to see what impact that move had on business. The company can see when a customer drove by its store to go to a competitor, and try to figure out why.

Mobext has already sold some of its retail clients on the idea and is performing its first studies with Locately, but it won't have the earliest results until February. "It's new, and not many people are thinking along these lines," says Truong, "but we're trying to guide our clients to think that way."

The ramifications for business are far-reaching. "I think the fundamental business of demographics is going to change very dramatically," says Sean Gorman, president of FortiusOne, a company in Arlington, Virginia, that recently launched a location analytics program. The software allows developers to build location analysis into their apps, giving them the ability to gather all kinds of data about consumer whereabouts.

This kind of tracking raises obvious issues of privacy. All these businesses profess sensitivity to such concerns. For research studies, companies spell out to the volunteers just what they'll be watching them do. Locately sets a time limit—generally about three months—on how long it will collect information. All the companies say they strip the data of personal identifiers. The collected information is aggregated, so researchers see the movement patterns of groups rather than individuals. And once they're done with it, they say, the personal data is discarded.

Whether these policies actually alleviate the concern is an open question. But with the right assurances and enticements, Truong says, people have actually been excited to sign up for the project. And Gorman says people are generally getting used to the idea of broadcasting where they are, through programs like Foursquare. "I think as more people realize the reward for identifying their location, it will become more popular," he says. Rewards could range from special-event invitations to limited-time discounts on meals.

It's too soon to put a dollar figure on the business value. Retailers haven't been getting the information long enough to change marketing strategies and see the results. As a result, they're not yet ready to discuss it.

But market research giants Nielsen and Harris Interactive have both started using Locately's technology, indicating that the potential is large. In the past, when companies such as Nielsen have sorted people into demographic groups, they've based their estimates on information like which U.S. Census block a person's zip code falls into. Now location analytics provides more accurate information more quickly, says Tony Jebara, chief scientist and cofounder of Sense Networks, a location data analytics company in New York.

By analyzing where people go as well as where they live, the company's algorithms are able to sort consumers into "tribes" such as college students and young urban professionals. Jebara says his company has deals with two cell-phone carriers that he won't name, which are using its software to develop aggregate profiles of customers. The carriers, in turn, will be able sell those profiles to marketing agencies or retailers.

Locately's Fulford-Jones is optimistic about the potential of location analytics to extract business value from data that couldn't be gathered before, assuming that consumers are willing to coƶperate. "The cool thing about this data," he says, "is because it's new, even small slivers of it are really helpful and useful to business."

Monday, 8 November 2010

Opening the Door to Ubiquitous Sensors - Nanogenerators

Original Article: Technology Today

Nanogenerator Powers Up

A device containing piezoelectric nanowires can now scavenge enough energy to power small electronic devices.

Power flex: This material contains
piezoelectric nanowires. When flexed,
it produces enough power to drive a
liquid-crystal display.
Credit: ACS/Nano Letters
Devices that harvest wasted mechanical energy could make many new advances possible—including clothing that recharges personal electronics with body movements, or implants that tap the motion of blood or organs. But making energy-harvesting devices that are compact, flexible, and, above all, efficient remains a big challenge. Now researchers at Georgia Tech have made the first nanowire-based generators that can harvest sufficient mechanical energy to power small devices, including light-emitting diodes and a liquid-crystal display.

The generators take advantage of materials that exhibit a property called piezoelectricity. When a piezoelectric material is stressed, it can drive an electrical current (applying a current has the reverse effect, making the material flex). Piezoelectrics are already used in microphones, sensors, clocks, and other devices, but efforts to harvest biomechanical energy using them have been stymied by the fact that they are typically rigid. Piezoelectric polymers do exist, but they aren't very efficient.

Zhong Lin Wang, who directs the Center for Nanostructure Characterization at Georgia Tech, has been working on another approach: embedding tiny piezoelectric nanowires in flexible materials. Wang was the first to demonstrate the piezoelectric effect at the nanoscale in 2005; since then he has developed increasingly sophisticated nanowire generators and used them to harvest all sorts of biomechanical energy, including the movement of a running hamster. But until recently, Wang hadn't developed anything capable of harvesting enough power to actually run a device.

In a paper published online last week in the journal Nano Letters, Wang's group describes using a nanogenerator containing more nanowires, over a larger area, to drive a small liquid crystal display.o make the generator, Wang's team dripped a solution containing zinc-oxide nanowires onto a thin metal electrode sitting on a sheet of plastic, creating several layers of the wires. They then covered the material with a polymer and topped it with an electrode. The resulting device is about 1.5 by two centimeters and, when compressed 4 percent every second, it produces about two volts, enough to drive a liquid-crystal display taken from a calculator. "We were generating 50 millivolts in the past, so this is an enhancement of about 20 times," says Wang.

In a paper published in Nano Letters this summer, Wang demonstrated a nanogenerator capable producing 11 milliwatts per cubic centimeter—enough to light up an LED. Wang notes that a pacemaker requires 5 milliwatts to run, an iPod 80 milliwatts. "We're almost there," he says.

The devices made by the Georgia Tech group are "getting into the realm where the power output is reasonable," says Michael McAlpine, professor of mechanical engineering at Princeton University and a 2010 TR35 awardee. "Getting impressive power outputs is a matter of scaling up," he adds.

Both Wang and McAlpine are looking to more efficient materials for making nanogenerators. Both have recently demonstrated making nanowires from PZT, a crystalline material that is standard in commercial piezoelectric devices. PZT, a compound that contains lead, zirconium, and titanium, is the most efficient piezoelectric material known, but making it into nanowires has been tricky because there are no good catalysts for growing PZT nanowires.

Wang and McAlpine have found different solutions to this problem. Wang treats his starting solution at high temperature and pressure, which does away with the need for an efficient catalyst. McAlpine grows a flat film of PZT, and then uses a mask to pattern nanowires through chemical etching. Energy harvesters made from PZT nanowires aren't as efficient as the zinc-oxide ones yet, but McAlpine says this is because he and Wang have only just begun to work with them.