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Market News

 April 11, 2012
Where Your Smartphone Energy Goes...

 New research out of Purdue University shows how free smartphone apps suck energy out of your phone. In summary, they spend 65-75% of their energy on "ad modules" --- "tracking the user's geographical location, sending information about the user to advertisers and downloading ads."

Well, as someone in the internet industry, I know that ads are financially responsible for many of the products and much of the content that we love --- without them, many of us simply wouldn't be able to do what we do. But 75% of energy --- wow. Good news is that the researchers are also working on a technique to reduce the energy usage of the apps by, so far, 20-65%.

Apps Sucking Your Smart Phone Dry

"It turns out the free apps aren't really free because they contain the hidden cost of reduced battery life," Y. Charlie Hu, a Purdue University professor of electrical and computer engineering, aptly notes. Power consumption isn't free, and it also isn't all that cheap.

That said, the research team has only examined 6 free apps so far, and there are millions out there.

In Hu and the team's work, they developed 'eprof' (for 'energy profiler'), which conducts a more detailed analysis than ever before of where a smartphone's energy goes. In the case of the extremely popular app Angry Birds, 25% of the energy went to playing the game and 75% went to the advertising modules. Hu noted they the team believed the energy is mainly used "to provide information about the user's geographical location so the ads can be more targeted or customized to that location," Hu said.

"Findings will be detailed in a research paper being presented during the EuroSys 2012 conference on April 10-13 in Bern, Switzerland," the Purdue news release stated. "The paper, written by Pathak, Hu and Ming Zhang, a researcher at Microsoft Research, also suggests a general approach for improving the energy efficiency of smartphone apps."

Fixing the Problem

It's often specific software flaws that actually suck a lot of the energy out of the smartphones. As such, some software-fixing technique could make a big difference.

Findings in the paper suggest a way to improve energy efficiency with a technique that has been shown to reduce the energy consumption of four apps by 20 percent to 65 percent.

The ultimate goal is to develop an "energy debugger" that automatically pinpoints flaws in software and fixes them without the intervention of a human software developer, Hu said.

Where did the impetus for this research begin? Apparently, some of the researchers had run into many reports of smartphone batteries dying far too quickly.

"We've been hearing about major problems lately in power usage," Hu said. "A smartphone battery is generally expected to last a day before recharging, but we're hearing about mysterious instances where the battery runs out in a few hours. Users have been complaining about this on Internet forums."