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Thursday, November 5th, 2015
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| 12:00a |
Game for climate adaptation Perhaps you have heard the adage “think globally, act locally.” An MIT-led project taking that idea to heart has demonstrated a new method for getting local citizens and leaders to agree on the best ways of managing the immediate and long-term effects of climate change.
The New England Climate Adaptation Project (NECAP) got local citizens and officials in four coastal towns to engage in role-playing games about climate change tailored to their communities, while conducting local polling about attitudes and knowledge about climate risks. In so doing, the project helped the towns reach new conclusions about local initiatives to address the threats posed by climate change— which in coastal communities may include rising sea levels and increased storm surges that can lead to flooding.
“One hour of conversation can completely alter people’s sense [and show] that this is a problem they can work on locally,” says Lawrence Susskind, the Ford Professor in Urban Studies in MIT’s Department of Urban Studies and Planning (DUSP), who led the project and has now co-authored a new book detailing its results. “There are a bunch of things local governments can do, and people can do for themselves — that communities can do.”
The findings stem from years of research and organizing in four places: Wells, Maine; Dover, New Hampshire; Barnstable, Massachusetts; and Cranston, Rhode Island. The new book on the effort, “Managing Climate Risks in Coastal Communities,” has just been released by the academic publisher Anthem Press.
Among the many findings of the project is that residents of these coastal communities were typically far more concerned about the consequences of climate change than local politicians realized.
“People in official positions really underestimated the extent to which [citizens] were worried about what climate change might mean to the town, what their vulnerabilities were,” Susskind explains. “If you asked, ‘What percentage of people do you think believe climate change is a problem right now?’ most officials would have said less than 10 percent. Our polling results were about 60 percent.”
The scenarios that the MIT-led team presented to people in each place involved ranges of probability regarding potential events. And yet, Susskind emphasizes, certain types of climate responses, like building better storm drains, may be necessary in almost any scenario.
“Lots of uncertainty doesn’t mean you can’t decide or know what to do,” Susskind says. “There are no-regrets actions you can take, where you won’t regret spending the money, time, or effort later.”
Four towns, many issues
The scholars chose the four towns because each hosts a center for the National Estuarine Research Reserve System, a branch of the National Oceanic and Atmospheric Administration. That made it simpler for the project leaders to make connections with local political leaders and convince them to participate in the climate adaptation project.
The book is co-authored by four project leaders, including Susskind, who heads the Environmental Policy and Planning Group at DUSP as well as the mediation group he founded, the Consensus Building Institute (CBI); Danya Rumore, visiting assistant professor at the University of Utah; Carrie Hulet, a senior associate at the CBI; and Patrick Field, co-managing director of the CBI and an associate director of the MIT-Harvard Public Disputes Program.
After developing climate-change scenarios for each town and conducting research on local political priorities and infrastructure, starting in 2012, the MIT group developed a role-playing game tailored to each town, and conducted debriefings on the issues as well. Citizens who participate study the local climate scenarios and potential responses, and try to reach consensus on plans of action. An investment of a few hours can suddenly make hundreds of community members more informed and willing to consider the need for climate response.
“The science doesn’t dictate things, but it informs things, and it leads to interesting conversations about what the policy for their own community should be,” Susskind says.
In Dover, for instance, the effort helped clarify the need to act on local concerns about flooding from the town’s river, and about the capabilities of the town’s storm drains; dredging the river and updating the drains are now higher priorities, along with having more generators on hand for emergency response activities. In Barnstable, where sea level rise, flooding, drought, and storm damage are all problematic issues, the project clarified the need to add water supplies and make the electrical grid more sustainable.
In Wells, where sea levels are projected to rise by 2 to 5 feet by 2099, the project highlighted the need for seawalls and a buyback program for privately owned coastal land that could absorb flooding. In Cranston, flooding is a major issue — following floods the town experienced in 2010 — and the project revealed that 86 percent of residents are concerned about climate change. Possible measures include engineered barriers and expanded wetlands, but the project also reveals a need for continued public education programs about the affordability of possible responses.
Still, acting sooner rather than later, Susskind suggests, will usually turn out to be a wise investment.
“Don’t be convinced that was a one-time flood,” he says. “It’s going to happen sooner and more often than you think, and the cost could be enormous without some effort to manage risks. And maybe as a community you say, ‘Bad things are going to happen unless we find some way to reduce our vulnerabilities.’”
Adaptation, as well as mitigation
The MIT-led project dealt with climate adaptation, the response to climate change risks. As Susskind acknowledges, that is only one part of the climate-action picture; the issue of climate mitigation — that is, preventing climate change from happening to the fullest extent possible — is also vital.
And while the role-playing games were limited to smaller communities, Susskind acknowledges, he thinks this approach can work in much larger municipalities as well, based on similar work he has done in Maryland and other places.
“I don’t think there are any problems of scaling up,” he says.
Other scholars have found the project and its results to be valuable. Judith Innes, a professor emerita of city and regional planning at the University of California at Berkeley, calls it an “eye-opening book” that offers “hope and guidance to policy makers and citizens who want to act before it is too late.”
The researchers have put many materials online, available for public study. However, Susskind says, there is no substitute for participating in the project’s games in person, to work through issues of evaluating a town’s needs and negotiating over them.
“The whole point politically is to organize a constituency for change in each locality, and that requires face-to-face interaction,” Susskind says. “There’s no substitute. I design different games for different places. You have to tailor it so that people get a sense they’re learning something about the place where they are. It’s about empowering a community to feel we can and should be working to anticipate and manage climate risks.” | | 12:00a |
Harvesting more energy from photons Researchers at MIT and elsewhere have found a way to significantly boost the energy that can be harnessed from sunlight, a finding that could lead to better solar cells or light detectors.
The new approach is based on the discovery that unexpected quantum effects increase the number of charge carriers, known as electrons and “holes,” that are knocked loose when photons of light of different wavelengths strikes a metal surface coated with a special class of oxide materials known as high-index dielectrics. The photons generate what are known as surface plasmons — a cloud of oscillating electrons that has the same frequency as the absorbed photons
The surprising finding is reported this week in the journal Physical Review Letters by authors including MIT’s Nicholas Fang, an associate professor of mechanical engineering, and postdoc Dafei Jin. The researchers used a sheet of silver coated with an oxide, which converts light energy into polarization of atoms at the interface.
“Our study reveals a surprising fact: Absorption of visible light is directly controlled by how deeply the electrons spill over the interface between the metal and the dielectric,” Fang says. The strength of the effect, he adds, depends directly on the dielectric constant of the material — a measure of how well it blocks the passage of electrical current and converts that energy into polarization.
“In earlier studies,” Fang says, “this was something that was overlooked.”
Previous experiments showing elevated production of electrons in such materials had been chalked up to defects in the materials. But Fang says those explanations “were not enough to explain why we observed such broadband absorption over such a thin layer” of material. But, he says, the team’s experiments back the newfound quantum-based effects as an explanation for the strong interaction.
The team found that by varying the composition and thickness of the layer of dielectric materials (such as aluminum oxide, hafnium oxide, and titanium oxide) deposited on the metal surface, they could control how much energy was passed from incoming photons into generating pairs of electrons and holes in the metal — a measure of the system’s efficiency in capturing light’s energy. In addition, the system allowed a wide range of wavelengths, or colors, of light to be absorbed, they say.
The phenomenon should be relatively easy to harness for useful devices, Fang says, because the materials involved are already widely used at industrial scale. “The oxide materials are exactly the kind people use for making better transistors,” he says; these might now be harnessed to produce better solar cells and superfast photodetectors.
“The addition of a dielectric layer is surprisingly effective” at improving the efficiency of light harnessing, Fang says. And because solar cells based on this principle would be very thin, he adds, they would use less material than conventional silicon cells.
Because of their broadband responsiveness, Fang says, such systems also respond much faster to incoming light: “We could receive or detect signals as a shorter pulse” than current photodetectors can pick up, he explains. This could even lead to new “li-fi” systems, he suggests — using light to send and receive high-speed data.
N. Asger Mortensen, a professor at Danish Technical University who was not involved in this work, says this finding “has profound implications for our understanding of quantum plasmonics. The MIT work really pinpoints … how plasmons are subject to an enhanced decay into electron-hole pairs near the surface of a metal.”
“Probing these quantum effects is very challenging both theoretically and experimentally, and this discovery of enhanced absorption based on quantum corrections represents an important leap forward,” adds Maiken Mikkelsen, an assistant professor of physics at
Duke University who also was not involved in this work. “I think there is no doubt that harnessing the quantum properties of nanomaterials is bound to create future technological breakthroughs.”
The team also included postdoc Qing Hu and graduate student Yingyi Yang at MIT, Daniel Neuhauser at the University of California at Los Angeles, Felix von Cube and David Bell at Harvard University, Ritesh Sachan at Oak Ridge National Laboratory, and Ting Luk at Sandia National Laboratories. The work was supported by the National Science Foundation and the Air Force Office of Scientific Research. | | 11:59p |
Amplifying — or removing — visual variation At the Siggraph Asia conference this week, MIT researchers presented a pair of papers describing techniques for either magnifying or smoothing out small variations in digital images.
The techniques could be used to produce more polished images for graphic-design projects, or, applied in the opposite direction, they could disclose structural defects, camouflaged objects, or movements invisible to the naked eye that could be of scientific interest.
Conceptually, the work builds on a long line of research from several groups in MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL), which sought to amplify minute motions in digital video. “In motion magnification, the deviations are over time, and the model is deviation from being perfectly static,” says Tali Dekel, a postdoc in CSAIL and a co-author on both papers. “Our method takes as input only a single image, and it looks for deviation in space. We don’t need to know time history to do that.”
One of the two papers, on which Dekel is first author, presents an algorithm that looks for repeated forms within an image, such as the kernels of an ear of corn or bricks in a wall. It can then iron out differences across the image, producing idealized but still natural-looking corn ears or brick walls, or amplify the differences, making them more evident to the naked eye.
The algorithm works with color as well as shape. So, for instance, it can take an image in which a chameleon is concealed against the trunk of a tree and enhance subtle color differences so that the chameleon stands out blue against an orange background.
Joining Dekel on that paper are professor of computer science and engineering William Freeman, whose group she’s a member of, and colleagues from Israel’s Technion and Weizmann Institute.
Imperfect form
The algorithm described in the other paper amplifies deviations from ideal geometries. The roofline of a house, for instance, could look perfectly straight to the naked eye but still sag toward the middle. The algorithm can exaggerate that type of flaw, potentially drawing attention to structural problems.
In other experiments, the algorithm was able to identify a rippling in Saturn’s rings that could offer information about the orbital pattern of the planet’s moons, and by magnifying changes to a regular pattern projected on a screen behind a candle, it revealed thermal variations caused by the candle’s flame.
The first author on that paper is Neal Wadhwa, another MIT graduate student in electrical engineering and computer science. Joining him are Dekel, Freeman, graduate student Donglai Wei, and Frédo Durand, a professor of computer science and engineering.
The first algorithm — the one that recognizes repeated forms — begins by comparing patches of the source image, at different scales, and identifying those that seem to be visually similar. Then it averages out all the visually similar patches and uses the averages to construct a new, highly regular version of the image. This image may look unnatural, but its purpose is just to serve as an initial target.
Then the algorithm identifies a mathematical function that moves the pixels of the source image around, producing the best possible approximation of the target image. From that function, it creates a new target image. It then iterates back and forth, producing ever more natural-looking target images and ever more regular mathematical transformations, until the two converge.
Once the algorithm has a function that produces a regular image, it can simply invert it to produce a more distorted image.
Implications
The technique works not only with geometrically simple forms like corn kernels and bricks but with more complex forms as well. So, for instance, it can take an image of a line of dancers executing the same kick and standardize their heights and the distances between them.
If it’s implemented particularly aggressively, it can even cut irregularities out of an image — for instance, standardizing the size and shape of the cells of a honeycomb while deleting the bees crawling over it. As such, it could be a useful resource for image-manipulation programs like Photoshop.
In materials science, a standard technique for identifying defects in a material’s surface is to cover it with tiny soap bubbles and look for irregularities. The MIT researchers are also collaborating with materials scientists to use their algorithm to enhance that process.
The second algorithm uses existing techniques to identify the geometric shapes indicated by color gradations in an image. Then it excises a narrow band of the image that traces the curve defining each of those shapes. It then straightens the bands out, creating a uniform representation of all the shapes in the image.
At regular intervals, it considers local variations in color across the width of each band. These will typically vary, indicating deviations from the idealized geometry of the initial curve. From those deviations, the algorithm constructs a new, more erratic curve, which it can exaggerate and then reinsert into the image.
“Humans are extremely good at detecting regularities or deviations from them,” says Shai Avidan, an associate professor of computer science at Tel Aviv University. “Computers can do that quite well when the irregularities are at a fairly large scale. But images have a finite resolution, and detecting irregularities at a tiny scale — at sub-pixel accuracy — requires truly impressive engineering skills. I have no doubt that the methods presented here will be used in various fields such as material inspection, civil engineering, and astronomy.” |
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