Pollock or Not? Can Fractals Spot a Fake Masterpiece?

Pollock or Not? Can Fractals Spot a Fake Masterpiece?

Complex geometric patterns turn up in non-Pollock drip paintings

	FRACTAL, BUT NOT A POLLOCK:  Researchers say that fractal patterns are no reliable way to distinguish genuine Pollock drip paintings from similar works such as this fractal-laced creation of two undergraduate students.

A new study attacks the technique of using fractals, the repeating patterns found in everything from coastlines to fern fronds, to help distinguish authentic Jackson Pollock drip paintings from paint splattered by lesser hands.

In a paper submitted for publication to a major physics journal, researchers report that previously published criteria for identifying genuine Pollocks based on the presence of fractals—patterns that recur in varying sizes like Russian dolls nested inside one another—would wrongly grant Pollock status to a pair of amateur drip paintings.

Some researchers, however, are skeptical that the new method faithfully replicates that of University of Oregon physicist Richard Taylor, who first reported eight years ago that five Pollock paintings contained distinctive splatters within splatters, which he has attributed to the way "Jack the Dripper" swayed over the canvas while dribbling paint from brushes, sticks or straight from the can.

The Pollock–Krasner Foundation, which represents the estates of Pollock and his wife Lee Krasner, commissioned Taylor last year to examine six of 32 alleged Pollock drip paintings for fractal clues as to whether the master dripper (dead since 1956) had truly created them; the paintings, discovered in 2003, turned up fractalless.

Upon learning the news, physicists Katherine Jones–Smith and Harsh Mathur of Case Western Reserve University in Cleveland, Ohio, published their own Nature paper reporting the discovery of a similar fractal signature in quick sketches of different size stars or circles.

Jones–Smith had drawn the images two years earlier while preparing a presentation on Taylor's work, which she initially believed was correct. Much to her surprise, she discovered that her unsophisticated images contained seemingly identical fractal patterns.

To rebut the obvious counterargument—that stars look nothing like drip paintings—she, Mathur and Case Western cosmologist Lawrence Krauss have now analyzed three known Pollock drip paintings that Taylor had not examined in detail: Free Form (1946), Untitled (circa 1950) and Wooden Horse: Number 10A, 1948.

STAR STRUCK:  This crude drawing of stars exhibited the same self-repeating fractal pattern as a Jackson Pollock drip painting, according to a 2006 study.

After using one of two separate computer techniques to isolate splatter marks of different colors, the researchers scanned for fractals in each layer of color by digitally counting colored pixels (or boxes) of various sizes. In this type of fractal, the number of boxes of each size relates to the box size raised to a power that holds constant over a range of sizes.

None of the Pollocks met stringent fractal criteria, although Free Form did satisfy what they consider a loose definition of a fractal and Wooden House failed its test in only two of six colors, they report in their paper submitted to Physical Review Letters, which has yet to be reviewed by other scientists.

Further complicating matters, the researchers identified fractals in two drip paintings created for the study by students [see image above]. They next examined two of the alleged Pollocks studied by Taylor, one of which, chosen for its resemblance to Free Form, passed the loose fractal test, whereas the other, resembling Wooden Horse, failed the test.

The new results clash with a 2006 Pattern Recognition Letters paper in which Taylor and colleagues reported identifying an identical fractal pattern in 14 known Pollocks but not among 37 drip paintings by University of Oregon undergraduates or 14 paintings of unknown origin thought to date to Pollock's era.

"Our position," Mathur says, "is that fractal analysis doesn't allow you to have a position" on the authenticity of a Pollock.

Hany Farid, a professor of computer science at Dartmouth College in New Hampshire who has followed the debate, says he sees flaws in the new study. "I think they took a fairly simplistic way of separating those colors," which he says could have skewed their results. 

Taylor argues that the researchers applied his fractal criteria incorrectly on Untitled and notes that their Wooden Horse analysis hinges on paint covering less than 5 percent of the canvas, which makes drawing conclusions tricky.

Moreover, he says, the group's conclusion turns on a misconception. "There's an image out there of fractal analysis where you send the image through a computer and if a red light comes on it means it isn't a Pollock and if a green light comes on it is. We have never supported or encouraged such a mindless view." 

Even if the new results are correct, Farid says, fractal analysis can still serve as one piece of evidence in the broader puzzle of authentication, which also involves historical and aesthetic judgments. Earlier this year, for example, a Harvard team reported that two pigments found in the 32 alleged Pollocks were not used in paints before 1996 and 1971.

"None of these tools stands by itself," Farid says.

Owners of authentic Pollocks, however, do stand to make a lot of money. Last year, the Pollock painting No. 5, 1948, was reportedly sold to a Mexican financier for a record $140 million. 

Robots Prepare for the Battlefield by First Fighting City Traffic

Robots Prepare for the Battlefield by First Fighting City Traffic

DARPA is set to crown the winner of its 2007 Urban Challenge, featuring autonomous autos that try to stop, go and merge as well as humans
 

	NO DRIVERS WANTED:  The Caltech team's 2004 Ford E350 van named Alice was equipped with 12 computers, eight cameras, two radar devices and eight laser range finders that measure distance by emitting infrared pulses.

As sophisticated as machines are today, they still cannot navigate an automobile through crowded city streets as well as experienced human drivers. But the Defense Advanced Research Projects Agency (DARPA) is working to change that with an eye toward sending automated robotic ground vehicles into battle to evacuate wounded soldiers, collect reconnaissance and carry out other dangerous missions.

This weekend DARPA, the U.S. Department of Defense's central research and development arm, will move closer to that goal when it hosts the final round of its 2007 DARPA Urban Challenge, a competition testing the driving prowess of experimental unmanned autos. The agency has whittled the field down from 89 to 11 teams of gearheads, scientists and students who will test their autonomous creations at the former George Air Force Base in Victorville, Calif. The winner will drive away with $2 million and those snagging second and third places will get $1 million and $500,000, respectively.

Unlike the DARPA Grand Challenges held in 2004 and 2005 in the Mojave Desert, this year's competition tests whether a vehicle—which must run entirely on its own using a system of sensors, global positioning systems and computers—can handle the types of driving conditions that city dwellers face every day, such as changing lanes, merging onto roadways with fast-moving traffic and traversing busy intersections. (Fortunately, they will not have to contend with iPod-wearing pedestrians, cell phone–gabbing drivers or unpredictable cabbies.)

Congress six years ago passed a measure mandating: "It shall be a goal of the Armed Forces to achieve the fielding of unmanned, remotely controlled technology such that…by 2015, one third of the operational ground combat vehicles are unmanned" with an eye toward one day handing over "dull, dirty or dangerous" tasks to machines.

The first Grand Challenge was held in March 2004 and featured a 142-mile (228.5-kilometer) desert course. Fifteen autonomous ground vehicles entered but nary a one made it to the finish line. The following year four autonomous vehicles successfully completed a 132-mile (212-kilometer) desert route within the required 10-hour limit. That year, "Stanley," a modified Stanford University Volkswagen Touareg R5 featuring six wireless laptop computers powered by Intel Pentium M processors running custom artificial intelligence software, claimed the top $2-million prize.

CROSSROADS:  Oshkosh Truck Corp.'s TerraMax unmanned ground vehicle—one of 11 finalists competing November 3—waits patiently for traffic to clear.

Despite the initial dearth of finishers (not to mention the absence of a competition last year as DARPA retooled the event), the agency is satisfied that the military is on the right track, DARPA public information officer Jan Walker says. But an autonomous vehicle must be able to traverse all types of terrain—from the city to the desert to the jungle to the mountains—to meet military demands. "The biggest difference with this year's competition," Walker says, "is that they have to be able to respond to a dynamic, unpredictable environment."

Despite the dramatic exploits of fictionalized robots in books and movies (who could forget the Terminator's skill behind the wheel?), artificial intelligence may not be up to the multitasking required to analyze the constantly changing conditions and other demands of driving. "The really interesting challenge in technology is building machines that do the types of things that people do so you can put [these machines] deep under the ocean or in outer space," says Richard Murray, a professor of control and dynamical systems at the California Institute of Technology's Division of Engineering and Applied Science. Murray's Caltech team entered the DARPA competition with a 2004 Ford E-350 van named Alice, whose artificial intelligence was created by the joint effort of 80 undergraduate and graduate students, postdoctoral candidates and faculty as well as engineers from NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Alas, despite some early success, Alice failed to advance to this weekend's final round. Equipped with eight cameras, two radar devices and eight laser range finders that measure distance by emitting infrared pulses, Alice nonetheless had trouble stopping and going at intersections and merging into traffic to DARPA's satisfaction. In one instance, Alice stopped at an intersection, advanced when the road was clear of traffic, but slowed down again because she mistakenly perceived a concrete guardrail to be an obstacle. "We would stop and not go and get honked at," Murray says. Alice at times also failed to identify the line in the road signaling her to stop at intersections and either stopped too late or not at all. (Although that may be good enough to get her a gig as a taxi in New York City.)

Alice has since been shipped back to Pasadena so that Murray and his team can study her computer's data logs and better understand her behavior. The van contains about a dozen computers running the open-source Linux operating system and a number of open-source software applications designed to process information gathered by the cameras, radar and laser range finders. Students plan to continue using Alice to test their research into the development of autonomous vehicles.

"Driving is a great example of something that humans [can] do really well that requires the need to think about a number of problems simultaneously, like working the pedals, steering the wheel and watching the road, all while thinking about where you're going," Murray says. "The DARPA challenges have really pushed the state of the art in that area." DARPA wants artificial intelligence that can measure a situation and make wise decisions based on the information it collects. "Right now we have people doing that," he says, "because we don't know how to make machines do it."

Melting Glacier Reveals Ancient Tree Stumps

Melting Glacier Reveals Ancient Tree Stumps

Melting glaciers in Western Canada are revealing tree stumps up to 7,000 years old where the region's rivers of ice have retreated to a historic minimum, a geologist said today.

Johannes Koch of The College of Wooster in Ohio found the fresh-looking, intact tree stumps beside retreating glaciers in Garibaldi Provincial Park, about 40 miles (60 kilometers) north of Vancouver, British Columbia.

Radiocarbon dating of the wood from the stumps revealed the wood was far from fresh—some of it dated back to within a few thousand years of the end of the last ice age.

"The stumps were in very good condition, sometimes with bark preserved," said Koch, who conducted the work as part of his doctoral thesis at Simon Fraser University in Burnaby, British Columbia. Koch will present his results on Oct. 31 at the Geological Society of America annual meeting in Denver.

The pristine condition of the wood, he said, can best be explained by the stumps having spent all of the last seven millennia under tens to hundreds of meters of ice. All stumps were still rooted to their original soil and location.

"Thus they really indicate when the glaciers overrode them, and their kill date gives the age of the glacier advance," Koch said. The age of the newly revealed ancient trees also indicates how long the glaciers have covered this region.

The recently warming climate released the stumps from their icy tombs, Koch said.

Koch compared the kill dates of the trees in the southern and northern Coast Mountains of British Columbia and those in the mid- and southern Rocky Mountains in Canada to similar records from the Yukon Territory, the European Alps, New Zealand and South America. He also looked at the age of Oetzi, the prehistoric mummified alpine "Iceman" found at Niederjoch Glacier, and similarly well-preserved wood from glaciers and snowfields in Scandinavia.

The radiocarbon dates seem to be the same around the world, according to Koch. There have been many advances and retreats of these glaciers over the past 7,000 years, but no retreats that have pushed them back so far upstream as to expose these trees.

The age of the tree stumps gives new emphasis to the well-documented before-and-after photographs of retreating glaciers during the past 100 years.

"It seems like an unprecedented change in a short amount of time," Koch said. "From this work and many other studies looking at forcings of the climate system, one has to turn away from natural ones alone to explain this dramatic change of the past 150 years."

Sphinx Glacier: 4,900 years old. Glacier in background. 

Scientists note brain's reaction to fear

Scientists note brain's reaction to fear

Science is getting a grip on people's fears. As Americans revel in all things scary on Halloween, scientists say they now know better what's going on inside our brains when a spook jumps out and scares us. Knowing how fear rules the brain should lead to treatments for a major medical problem: When irrational fears go haywire.

"We're making a lot of progress," said University of Michigan psychology professor Stephen Maren. "We're taking all of what we learned from the basic studies of animals and bringing that into the clinical practices that help people. Things are starting to come together in a very important way."

About 40 million Americans suffer from anxiety disorders, according to the National Institute of Mental Health. A Harvard Medical School study estimated the annual cost to the U.S. economy in 1999 at roughly $42 billion.

Fear is a basic primal emotion that is key to evolutionary survival. It's one we share with animals. Genetics plays a big role in the development of overwhelming — and needless — fear, psychologists say. But so do traumatic events.

"Fear is a funny thing," said Ted Abel, a fear researcher at the University of Pennsylvania. "One needs enough of it, but not too much of it."

Armi Rowe, a Connecticut freelance writer and mother, said she used to be "one of those rational types who are usually calm under pressure." She was someone who would downhill ski the treacherous black diamond trails of snowy mountains. Then one day, in the midst of coping with a couple of serious illnesses in her family, she felt fear closing in on her while driving alone. The crushing pain on her chest felt like a heart attack. She called 911.

"I was literally frozen with fear," she said. It was an anxiety attack. The first of many.

The first sign she would get would be sweaty palms and then a numbness in the pit of the stomach and queasiness. Eventually it escalated until she felt as if she was being attacked by a wild animal.

"There's a trick to panic attack," said David Carbonell, a Chicago psychologist specializing in treating anxiety disorders. "You're experiencing this powerful discomfort but you're getting tricked into treating it like danger."

These days, thanks to counseling, self-study, calming exercises and introspection, Rowe knows how to stop or at least minimize those attacks early on.

Scientists figure they can improve that fear-dampening process by learning how fear runs through the brain and body.

The fear hot spot is the amygdala, an almond-shaped part of the deep brain.

The amygdala isn't responsible for all of people's fear response, but it's like the burglar alarm that connects to everything else, said New York University psychology and neural science professor Elizabeth Phelps.

Emory University psychiatry and psychology professor Michael Davis found that a certain chemical reaction in the amygdala is crucial in the way mice and people learn to overcome fear. When that reaction is deactivated in mice, they never learn to counter their fears.

Scientists found D-cycloserine, a drug already used to fight hard-to-treat tuberculosis, strengthens that good chemical reaction in mice. Working in combination with therapy, it seems to do the same in people. It was first shown effective with people who have a fear of heights. It also worked in tests with other types of fear, and it's now being studied in survivors of the World Trade Center attacks and the Iraq war.

The work is promising, but Michigan's Maren cautions that therapy will still be needed: "You're not going to be able to take a pill and make these things go away."

When it comes to ruling the brain, fear often is king, scientists say.

"Fear is the most powerful emotion," said University of California Los Angeles psychology professor Michael Fanselow.

People recognize fear in other humans faster than other emotions, according to a new study being published next month. Research appearing in the journal Emotion involved volunteers who were bombarded with pictures of faces showing fear, happiness and no expression. They quickly recognized and reacted to the faces of fear — even when it was turned upside down.

"We think we have some built-in shortcuts of the brain that serve the role that helps us detect anything that could be threatening," said study author Vanderbilt University psychology professor David Zald.

Other studies have shown that just by being very afraid, other bodily functions change. One study found that very frightened people can withstand more pain than those not experiencing fear. Another found that experiencing fear or merely perceiving it in others improved people's attention and brain skills.

To help overcome overwhelming fear, psychologist Carbonell, author of the "Panic Attacks Workbook," has his patients distinguish between a real threat and merely a perceived one. They practice fear attacks and their response to them. He even has them fill out questionnaires in the middle of a fear attack, which changes their thinking and causes reduces their anxiety.

That's important because the normal response for dealing with a real threat is either flee or fight, Carbonell said. But if the threat is not real, the best way to deal with fear is just the opposite: "Wait it out and chill." 

Vanderbilt University psychology professor David Zald is shown in front of his Nashville, Tenn. home...

Turbine expansion said to threaten birds

Turbine expansion said to threaten birds

Wind energy may be emerging as an important alternative power source for the Northwest, but there are concerns about the danger to hawks and eagles as turbines expand to wild areas of the Columbia River Gorge.

By year's end, more than 1,500 turbines will be churning out electricity in the windy gorge. Until now, most of the projects have gone up in wheat fields — cultivated land that long ago drove away the rodents that raptors hunt. But as wind energy developers move into wilder areas along the ridge of the gorge, near canyons and shrub-covered rangeland, birds could be at risk from the 150-foot blades of giant turbines.

The shrub steppes and grasslands that cover large areas along the river east of the Cascades are classic raptor habitat, said David Anderson, a district biologist with the Washington Department of Fish and Wildlife.

"We have concerns we're losing that habitat," he said.

Even the cultivated areas with wind farms have bird experts worried. In Oregon's Sherman County, several hundred turbines stretch through wheat fields outside the small town of Wasco, creating one of the highest concentrations of wind farms in the gorge.

"They're going up so fast, we're worried about the cumulative effects," said Keith Kohl, a wildlife biologist for the Oregon Department of Fish and Wildlife's mid-Columbia district.

If new studies confirm the fears of Oregon and Washington state wildlife biologists, the potential toll on raptors and other birds may limit expansion of clean wind energy.

Nationwide, wind turbines kill an average of 2.3 birds a year, studies show. In the Northwest, it's about 1.9 birds per turbine — possibly more than 3,000 bird deaths a year in the gorge.

But bird experts say those numbers are meaningless because the totals make no distinction between abundant and rare species.

Golden eagles and ferruginous hawks — a threatened species in Washington — already are few in number, said Michael Denny of the Blue Mountain Audubon Society. Even a few fatalities could prove devastating, he said.

"We'll have certain species in sharp local decline," Denny said. "If you lose breeding populations like the ferruginous hawk, you're not going to see them recover."

Raptors generally fly 300 to 400 feet above the ground — about the height of most wind turbines. Hawks and eagles ride the thermals off the high windy ridges above the Columbia River as they search for ground squirrels and pocket gophers. Some are migratory and others are resident birds.

Raptors are known for their keen eyesight and might learn to negotiate the turbines and their spinning blades, studies suggest.

But hunting and migrating instincts are so ingrained and so intense that the birds might not see the obstacles until it's too late, biologists say.

As a preventive measure, energy companies conduct wildlife studies before designating a specific site for development. They submit their findings to state or county authorities, who decide whether projects will go forward.

In some cases, regulators have required developers to shift turbine locations, establish buffer zones or set aside acreage exclusively for wildlife.

Often, developers must patrol their wind farms and record bird kills.

"We pride ourselves on building projects that adhere to the requirements," said Darin Huseby, Northwest regional director for developer enXco Inc., a California-based company with several projects in Klickitat County, Wash. "We want to be a net benefit to the environment."