时文阅读3

Blog mining

Scouring blogs for useful information

Mar 11th 2010 | From The Economist print edition

“I NOTICED that the doormat was at a slightly crooked angle. I reached down and moved the mat back into its correct place.” Thus began a recent entry on The dullest blog in the world. Although this publication is something of a satire on the internet’s inane blogs, scientists are finding—to their surprise—that useful information can actually be mined from the tedium of the blogosphere.

Andrew Gordon and his c olleagues at the University of Southern California’s Institute for Creative Technologies in Los Angeles have been trying to teach computers about cause and effect. Computers are not good at dealing with causality. They can identify particular events but working out relationships is more difficult. This is particularly true when it comes to using computers to analyse the human experience.

But it turns out that computers can learn a lot about causality by reading personal blogs. Of the million or so blog entries that are written in English every day, most are comments on news, plans for activities, or personal thoughts about life. Roughly 5% are narratives telling stories about events that have recently happened to the author.

To enable their computer system to learn from blogs, the team followed a two-step process. The first step was for humans to flag thousands of blog entries as either “story” or “not story”. People use different words with different frequencies when they are telling stories, as compared with other forms of discourse. By tallying up the frequencies of parts of speech such as pronouns (I, she, we) and past-tense verbs (went, said, thought) in these flagged blogs, it is possible to distinguish between the two types—regardless of what the story is actually about, says Dr Gordon. His computer system could then look at other blog entries and work out whether they were narrative or not.

The second step was to teach the system to identify causal connections. Here the team used much the same technique. Dr Gordon and his students read thousands of random blog entries and specifically pointed out phrasing associated with causal relationships (such as “I did X so then Y happened”) for the computer to pick up on. Identifying such phrases in blog entries then enables the computer to pick out and categorise those sentences that contain a cause and an effect, such as “I slammed on the brakes but ended up smashing into the car in front of me” or “The doctor scolded me for eating too much fat and risking a hea rt condition.”

The idea is that this will eventually lead to a system that can gather aggregated statistics on a day-by-day basis about the personal lives of large populations—information that would be impossible to garner from any other source. Ultimately, Dr Gordon expects the analysis of personal stories in weblogs to be used much like Google’s flu tracker, but on a much grander scale. Google’s flu-tracking scheme can detect early signs of influenza outbreaks by mining search data for flurries of flu-related search terms in a particular region.

The web could be mined to track information about emerging trends and behaviours, covering everything from drug use or racial tension to interest in films or new products. The nature of blogging means that people are quick to comment on events in their daily lives. Mining this sort of information might therefore also reveal information about exactly how ideas are spread and trends are set.

In the world before the web, chatter about the trivialities of everyday life was shared in person, and not written down, so it could not be subjected to such analysis. While recording their words for posterity and obsessively checking their hit counters to see if anyone is reading them,

today’s blog authors can console themselves with the thought that computers, at least, find their work fascinating.

18- to 24-year-olds most at risk for ID theft, survey finds

Washington Post Staff Writer

Wednesday, March 17, 2010

Ryan Thomas, an airman in the Air Force Honor Guard, bought some DVDs on the Internet using his debit card. It was a $20 payment made from his account, which had about $900.

But the following day, his account balance was zero.

Someone had stolen his account information and bought computer games and other items.

"I didn't know better about securing your information on the computer," said Thomas, 21, who lives in Southeast Washington and flies planes over Arlington National Cemetery during funerals. After the 2007 incident, Thomas took a class about how to protect information in cyberspace. But last month, he was hit again, this time by someone who targeted his account from Malaysia.

Similar identity-theft cases are rising sharply across the country, as young people -- sometimes cavalier with their personal information -- are hit the hardest, according to a survey released last month.

Identity fraud can include stealing a credit card number or opening a bank account in someone else's name. Thieves generally cross state lines in the commission of their crimes and are often linked to rings overseas in places such as Russia and Spain.

The "core millennial" group, identified as people ages 18 to 24, is at the greatest risk because it takes them longer to figure out that they have been defrauded -- meaning their information is compromised for a longer period, according to the survey, which is a snapshot of the identity fraud landscape from last year.

"Millennials don't protect enough or detect enough," said James Van Dyke, president of Javelin Strategy & Research, a California-based company that examined where identity theft threats are coming from and what effects they are having on consumers.

It takes young people an average of 132 days to detect fraudulent activity on their credit cards, bank accounts and other personal holdings, and those in older age groups average 49 days, the survey shows. When their identities are stolen, millennials are victimized by thieves for an average of about five months.

"The 18-to-24 group is unique. They're going to college. They're away from home for the first time. They're sharing more information. More of their information is exposed," Van Dyke said. "The old stereotype is true that people are sharing information willy-nilly and are waiting until they become a victim to listen to sound advice."

Thieves stole $400 from law student Gregory Peltz after he opened a tab at an Ohio dive bar, giving the bartender his debit card for the evening as he rang up drinks. He was shocked when his bank called him days later and told him that someone had withdrawn cash from the account, even without the card.

"I felt clueless," said Peltz, a second-year student at Ohio Northern University College of Law. He said he would have no problem handing over his debit card again for a night out at a bar -- just not the same dive as last time.

"I got my cash back the next day," Peltz, 25, said.

Last year, there were an estimated 11.1 million identity fraud victims of all ages, a 12 percent increase from the year before, according to the survey. Thieves stole about $54 billion from them, according to the study, which surveyed 5,000 people nationwide, 703 of whom had been victims of identity theft.

Javelin Research, which sells data studies to businesses and consumers, conducts surveys of consumer attitudes and behaviors on a variety of financial matters, including security, risk and fraud.

Its most recent identity fraud study found that in addition to well-known methods of thievery such as stealing wallets and credit cards, criminals are increasingly using high-tech methods of pilfering.

Among the common schemes: phishing (in which e-mails direct a victim to fraudulent Web sites that mimic respectable entities, including banks), smishing (in which text messages bait a victim to download malicious spyware), pharming (in which malicious code on computer sends victims to bogus Web sites) and keylogging (in which hidden software monitors victims' keystrokes to collect passwords).

When people are victimized with those methods, it's much harder to detect, often leaving them with no explanation about how their identities were stolen. Only about half of the victims file police reports, the study found.

Identity thieves steal an average of $4,841 per victim, but the end cost to each person is about $373, because banks generally reimburse the victims. Victims spend about 21 hours resolving their cases and getting their money back, the survey shows.

The study looked at social networking sites such as Facebook and MySpace and found that millennials are compromised more than other groups on the sites but that, in general, the sites account for small percentages of identity theft. Seven percent of young people said their financial information was compromised because of a social networking site, compared with 2 to 4 percent for other age groups.

But there's a caveat: About 55 percent of victims never figure out how their information was stolen.

Mary Madden, senior research specialist at the Pew Research Center's Internet and & American Life Project, said 72 percent of millennials use social networking sites daily, compared with 40 percent of adults 30 or older.

She said young people share personal information about themselves, whether it is their birth date, phone number or a picture from a party, as a way to nourish relationships.

"You are trading information about yourself as a form of cultural currency," Madden said. "By posting a photo or an update about what you did at a bar last night, you are sharing with friends to initiate an exchange and continue a friendship."

Problems arise, she said, when the information is misused.

"It's an interesting balance they have to strike in deciding how much to share in order to initiate or maintain a relationship but not overshare with their network," she said.

Madden pointed to studies that show most people can be identified with three pieces of information: their sex, Zip code and date of birth. And seemingly anonymous profiles that catalogue preferences, such as movie lists on Netflix, can also be used to identify users.

Adam Morrison, 19, a freshman at Arizona State University, realized that his identity had been stolen a few summers ago when he applied for a job and figured out that someone had been using his Social Security number for his own employment purposes. Morrison's bank account was not affected, but he remains miffed about how long the person had been using the Social Security number and how it was stolen.

"No idea how he got it," Morrison said.

Can Local 'Domes' of Carbon Dioxide Affect Human Health?

Science America March 17, 2010

A running mantra through the climate debate is that global warming is global indeed. Now, however, a scientist has found that localized "CO2 domes" could increase urban smog and other air pollution problems.

In a study published in Environmental Science & Technology, Stanford University professor Mark Jacobson estimated that the effect could cause the premature deaths of 50 to 100 people a year in California and 300 to 1,000 for the continental United States. By comparison, anywhere from 50,000 to 100,000 people a year die in air pollution-related deaths.

The finding, he says, could justify a regional or local approach to cutting greenhouse gas emissions.

Nearly all global and national emissions reduction plans operate on the assumption that a ton of CO2 from a coal plant in China or Ohio has the same climate effect as a ton from cars stuck in traffic on the Los Angeles freeway. Instead, he said, the local health effects of those emissions should also be considered.

"For better or worse, there is this local effect of CO2. That does give us scientific basis for controlling CO2 based on its local impact," said Jacobson.

Already, one California environmental coalition has seized on what it has termed the "Jacobson Effect" in its efforts to oppose the construction of new fossil fuel-burning power plants, such as a new natural gas-fired Russell City Energy Center recently permitted in Hayward, Calif. Calif. environmental groups following up

"It's very rigorous and compelling, to say the least. It's certainly an argument we will use," said Rory Cox, California program director of Pacific Environment and a member of the Local Clean Energy Alliance.

The concept of an urban "CO2 dome" has been known and documented for a decade, Jacobson said. Even though carbon dioxide is a long-lived pollutant that eventually spreads all around the globe, concentrations have been found to be anywhere from 20 to 100 parts per million higher around big cities, where there are many more constantly emitting smokestacks and tailpipes, according to him.

Many studies have linked increased air pollution to rising temperatures, but this is usually discussed in the context of rising global emissions. Jacobson said that no one before has explored how local CO2 emissions might hurt local residents.

Through detailed air modeling, Jacobson discovered that elevated CO2 levels could increase local temperature, change urban water vapor and wind patterns, and stagnate the air column above cities.

The result would be a direct increase in smog-forming ozone and particulate matter concentrations -- and thus an increase in the air pollution death toll -- he found.

MIT climate expert blames other factors

Chein Wang, a Massachusetts Institute of Technology air quality and climate modeler, was a bit skeptical that elevated local CO2 concentrations could substantially increase air pollution risks. Likely a larger influence, he said, is a common urban problem called the "heat island effect," caused when heat-absorbing paved surfaces and rooftops turn cities into saunas.

"The idea is there, but whether it matters quantitatively, I'm not sure. The urban heat island effect is also a big driver," he said.

Jacobson first began studying the issue when former U.S. EPA Administrator Stephen Johnson denied California a waiver it needed to begin regulating tailpipe emissions of CO2 on its own. Johnson argued that California's actions alone to slow global warming would not lead to any appreciable air quality improvements in the notoriously polluted state.