or perhaps even vehicles. Detailed studies of aerodynamics have shown that while a ball with a dimpled surface has half the drag of a smooth one at lower speeds,
at higher speeds that advantage reverses. So the ideal would be a surface whose smoothness can be altered, literally, on the fly and that
The new work is described in a paper in the journal Advanced Materials by MIT Pedro Reis and former MIT postdocs Denis Terwagne (now at the Université Libre de Bruxelles in Belgium) and Miha
Brojan (now at the University of Ljubljana in Slovenia. The ability to change the surface in real time comes from the use of a multilayer material with a stiff skin and a soft interior the same basic configuration that causes smooth plums to dry into wrinkly prunes.
an assistant professor of mechanical engineering and civil and environmental engineering. ess is known about what happens when you curve the surface.
Terwagne says that making the morphable surfaces for lab testing required a great deal of trial-and-error work that ultimately yielded a simple and efficient fabrication process. his beautiful simplicity to achieve a complex functionality is used often by nature,
For example, many radar antennas are housed in spherical domes, which can collapse catastrophically in very high winds.
Another application could be the exterior of automobiles, where the ability to adjust the texture of panels to minimize drag at different speeds could increase fuel efficiency,
he says. John Rogers, a professor of materials research and engineering at the University of Illinois at Urbana-Champaign who was involved not in this work,
says, t represents a delightful example of how controlled processes of mechanical buckling can be used to create three-dimensional structures with interesting aerodynamic properties.
The type of dynamic tuning of sophisticated surface morphologies made possible by this approach would be difficult
The research was supported by the National Science Foundation, MIT Charles E. Reed Faculty Initiatives Fund, the Wallonie-Bruxelles International, the Belgian American Education Foundation,
#Researchers unveil experimental 36-core chip The more cores or processing units a computer chip has,
the bigger the problem of communication between cores becomes. For years, Li-Shiuan Peh, the Singapore Research Professor of Electrical engineering and Computer science at MIT, has argued that the massively multicore chips of the future will need to resemble little Internets,
where each core has associated an router, and data travels between cores in packets of fixed size.
This week, at the International Symposium on Computer architecture, Peh group unveiled a 36-core chip that features just such a etwork-on-Chip in addition to implementing many of the group earlier ideas
it also solves one of the problems that has bedeviled previous attempts to design networks-on-chip:
maintaining cache coherence, or ensuring that coreslocally stored copies of globally accessible data remain up to date.
In today chips, all the cores typically somewhere between two and six are connected by a single wire,
called a bus . When two cores need to communicate, theye granted exclusive access to the bus. But that approach won work as the core count mounts:
Cores will spend all their time waiting for the bus to free up, rather than performing computations.
In a network-on-chip, each core is connected only to those immediately adjacent to it. ou can reach your neighbors really quickly,
says Bhavya Daya, an MIT graduate student in electrical engineering and computer science, and first author on the new paper. ou can also have multiple paths to your destination.
So if youe going way across, rather than having one congested path, you could have multiple ones.
One advantage of a bus, however, is that it makes it easier to maintain cache coherence.
Every core on a chip has its own cache a local, high-speed memory bank in which it stores frequently used data.
As it performs computations, it updates the data in its cache, and every so often, it undertakes the relatively time-consuming chore of shipping the data back to main memory.
But what happens if another core needs the data before it been shipped? Most chips address this question with a protocol called noopy,
because it involves snooping on other corescommunications. When a core needs a particular chunk of data, it broadcasts a request to all the other cores,
and whichever one has the data ships it back. If all the cores share a bus,
then when one of them receives a data request, it knows that it the most recent request that been issued.
Similarly, when the requesting core gets data back, it knows that it the most recent version of the data.
But in a network-on-chip data is flying everywhere, and packets will frequently arrive at different cores in different sequences.
The implicit ordering that the snoopy protocol relies on breaks down. Daya, Peh, and their colleagues solve this problem by equipping their chips with a second network, which shadows the first.
The circuits connected to this network are very simple: All they can do is declare that their associated cores have sent requests for data over the main network.
But precisely because those declarations are so simple, nodes in the shadow network can combine them
and pass them on without incurring delays. Groups of declarations reach the routers associated with the cores at discrete intervals intervals corresponding to the time it takes to pass from one end of the shadow network to another.
Each router can thus tabulate exactly how many requests were issued during which interval, and by which other cores.
The requests themselves may still take a while to arrive, but their recipients know that theye been issued.
During each interval, the chip 36 cores are given different, hierarchical priorities. Say, for instance, that during one interval,
both core 1 and core 10 issue requests, but core 1 has a higher priority.
Core 32 router may receive core 10 request well before it receives core 1 . But it will hold it until it passed along 1. This hierarchical ordering simulates the chronological ordering of requests sent over a bus,
so the snoopy protocol still works. The hierarchy is shuffled during every interval, however, to ensure that in the long run,
all the cores receive equal weight. Cache coherence in multicore chips s a big problem, and it one that gets larger all the time,
says Todd Austin, a professor of electrical engineering and computer science at the University of Michigan. heir contribution is an interesting one:
Theye saying, et get rid of a lot of the complexity that in existing networks. That will create more avenues for communication,
and our clever communication protocol will sort out all the details. It a much simpler approach and a faster approach.
It a really clever idea. ne of the challenges in academia is convincing industry that our ideas are practical and useful,
Austin adds. heye really taken the best approach to demonstrating that, in that theye built a working chip.
I be surprised if these technologies didn find their way into commercial products. After testing the prototype chips to ensure that theye operational
Daya intends to load them with a version of the Linux operating system, modified to run on 36 cores,
and evaluate the performance of real applications, to determine the accuracy of the group theoretical projections.
At that point, she plans to release the blueprints for the chip, written in the hardware description language Verilog,
as open-source code i
#A new way to detect leaks in pipes Explosions caused by leaking gas pipes under city streets have made frequently headlines in recent years,
including one that leveled an apartment building in New york this spring. But while the problem of old and failing pipes has garnered much attention,
methods for addressing such failing infrastructure have lagged far behind. Typically, leaks are found using aboveground acoustic sensors,
which listen for faint sounds and vibrations caused by leakage, or in-pipe detectors, which sometimes use video cameras to look for signs of pipe breaks.
But all such systems are very slow and can miss small leaks altogether. Now researchers at MIT and King Fahd University of Petroleum and Minerals (KFUPM) in Saudi arabia have devised a robotic system that can detect leaks at a rapid pace and with high accuracy by sensing a large pressure
change at leak locations. The concept was presented at two recent international conferences, and has been described in several recent papers.
This new system an detect leaks of just 1 to 2 millimeters in size, and at relatively low pressure, says Dimitrios Chatzigeorgiou,
a Phd student in mechanical engineering at MIT and lead author of the research papers. ee proved that the concept works.
The researchers have begun discussions with gas companies and water companies the system can also detect leaks in water pipes,
or in petroleum pipelines about setting up field tests under real-world conditions. Chatzigeorgiou presented the concept this month at the International Conference on Robotics and Automation in Hong kong,
and at the American Control Conference in Portland, Ore. Current acoustic tests are only effective for detecting sound and vibration in metal pipes,
Chatzigeorgiou says; plastic pipes tend to dissipate the sounds too quickly. Such systems are also time-consuming
and require expert operators, he says, whereas the small robotic device he and his collaborators have developed can move as fast as 3 mph through pipes,
and are automated almost entirely. Ultimately, he says, such devices could be put into a system of pipes
and left in place indefinitely, conducting automatic, nonstop monitoring of the system. In addition to their potential for dangerous explosions, leaking gas pipes can be a significant contributor to global warming:
Methane, the primary constituent of natural gas, is a greenhouse gas 25 times more potent than carbon dioxide.
Leaks in water pipes can waste up to half the water in a system; oil-pipeline leaks can lead to toxic spills and prolonged, expensive cleanup operations.
All of these systems could benefit significantly from improved leak-detection methods, Chatzigeorgiou says. While existing detection systems work under certain conditions,
Chatzigeorgiou says, there is not yet an approach that can efficiently detect leaks in any of these pipe systems. e believe this can solve the general problem,
he says: The new device could be produced in various sizes to fit different kinds of pipes,
and should be effective in gas, water, and oil pipes. MIT mechanical engineering professor Kamal Youcef-Toumi, a co-author of the research papers,
adds, his technology allows for an unambiguous and reliable sensing of very small leaks that often go undetected for long periods of time.
The current device consists of two parts: a small robot, with wheels to propel it through pipes (or, in some cases,
pulling it slightly toward the leak site. That distortion can be detected by force-resistive sensors via a carefully designed mechanical system (similar to the sensors used in computer trackpads),
and the information sent back via wireless communications. Detecting leaks by sensing a pressure gradient close to leak openings is a novel idea
Chatzigeorgiou says, and key to the effectiveness of this method: This approach can sense a rapid change in pressure close to the leak itself, providing pinpoint accuracy in locating leaks.
At present, the 3 mph top speed of the device is imposed by the propulsion motors, not the detector itself,
a professor of mechanical engineering at KFUPM, says that current leak-detection systems are quite expensive, typically costing $250,
Arnold Scott, vice chairman and director of First Commons Bank, who was involved not in this research but mentored the group in the MIT $100k Entrepreneurship Competition, says this approach s very important because of its size.
Using GPS, this device can specifically locate and report the location of a leak in a pipe.
The research was supported by KFUPM through the Center for Clean water and Energy at MIT f
#Who s using your data? By now most people feel comfortable conducting financial transactions on the Web.
The cryptographic schemes that protect online banking and credit card purchases have proven their reliability over decades.
As more of our data moves online a more pressing concern may be its inadvertent misuse by people authorized to access it.
Every month seems to bring another story of private information accidentally leaked by governmental agencies or vendors of digital products or services.
At the same time tighter restrictions on access could undermine the whole point of sharing data. Coordination across agencies and providers could be the key to quality medical care;
you may want your family to be able to share the pictures you post on a social-networking site.
Researchers in the Decentralized Information Group (DIG) at MIT s Computer science and Artificial intelligence Laboratory (CSAIL) believe the solution may be transparency rather than obscurity.
To that end they re developing a protocol they call HTTP with Accountability or HTTPA which will automatically monitor the transmission of private data
and allow the data owner to examine how it s being used. At the IEEE s Conference on Privacy Security and Trust in July Oshani Seneviratne an MIT graduate student in electrical engineering and computer science and Lalana Kagal a principal research scientist at CSAIL will present a paper
that gives an overview of HTTPA and presents a sample application involving a health-care records system that Seneviratne implemented on the experimental network Planetlab.
DIG is directed by Tim Berners-Lee the inventor of the Web and the 3com Founders Professor of Engineering at MIT and it shares office space with the World wide web Consortium (W3c) the organization also led by Berners-Lee that oversees the development of Web protocols like HTTP XML and CSS.
DIG s role is to develop new technologies that exploit those protocols. With HTTPA each item of private data would be assigned its own uniform resource identifier (URI) a key component of the Semantic web a new set of technologies championed by W3c that would convert the Web from essentially a collection of searchable
text files into a giant database. Remote access to a Web server would be controlled much the way it is now through passwords and encryption.
But every time the server transmitted a piece of sensitive data it would also send a description of the restrictions on the data s use.
And it would log the transaction using only the URI somewhere in a network of encrypted special-purpose servers.
HTTPA would be voluntary: It would be up to software developers to adhere to its specifications when designing their systems.
But HTTPA compliance could become a selling point for companies offering services that handle private data.
It s not that difficult to transform an existing website into an HTTPA-aware website Seneviratne says.
On every HTTP request the server should say OK here are the usage restrictions for this resource and log the transaction in the network of special-purpose servers.
An HTTPA-compliant program also incurs certain responsibilities if it reuses data supplied by another HTTPA-compliant source.
Suppose for instance that a consulting specialist in a network of physicians wishes to access data created by a patient s primary-care physician
and suppose that she wishes to augment the data with her own notes. Her system would then create its own record with its own URI.
But using standard Semantic web techniques it would mark that record as derived from the PCP s record
and label it with the same usage restrictions. The network of servers is where the heavy lifting happens.
When the data owner requests an audit the servers work through the chain of derivations identifying all the people who have accessed the data and what they ve done with it.
Seneviratne uses a technology known as distributed hash tables the technology at the heart of peer-to-peer networks like Bittorrent to distribute the transaction logs among the servers.
Redundant storage of the same data on multiple servers serves two purposes: First it ensures that
if some servers go down data will remain accessible. And second it provides a way to determine
whether anyone has tried to tamper with the transaction logs for a particular data item such as to delete the record of an illicit use.
A server whose logs differ from those of its peers would be easy to ferret out.
To test the system Seneviratne built a rudimentary health-care records system from scratch and filled it with data supplied by 25 volunteers.
She then simulated a set of transactions pharmacy visits referrals to specialists use of anonymized data for research purposes
and the like that the volunteers reported as having occurred over the course of a year.
Seneviratne used 300 servers on Planetlab to store the transaction logs; in experiments the system efficiently tracked down data stored across the network
and handled the chains of inference necessary to audit the propagation of data across multiple providers.
In practice audit servers could be maintained by a grassroots network much like the servers that host Bittorrent files or log Bitcoin transactions s
#Diagnosing broken buildings to make them greener The cofounders of MIT spinout KGS Buildings have a saying:
ll buildings are broken. Energy wasted through faulty or inefficient equipment, they say, can lead to hundreds of thousands of dollars in avoidable annual costs.
That why KGS aims to ake buildings betterwith cloud-based software, called Clockworks, that collects existing data on a building equipment specifically in HVAC (heating, ventilation,
and air conditioning) equipment to detect leaks, breaks, and general inefficiencies, as well as energy saving opportunities. The software then translates the data into graphs, metrics,
and text that explain monetary losses, where it available for building managers, equipment manufacturers, and others through the cloud.
Building operators can use that information to fix equipment prioritize repairs, and take efficiency measures such as using chilly outdoor air, instead of air conditioning,
to cool rooms. he idea is to make buildings better, by helping people save time, energy,
and money, while providing more comfort, enjoyment, and productivity, says Nicholas Gayeski SM 7, Phd 0, who co-founded KGS with Sian Kleindienst SM 6, Phd 0 and Stephen Samouhos 4, SM 7,
Phd 0. The software is now operating in more than 300 buildings across nine countries, collecting more than 2 billion data points monthly.
The company estimates these buildings will save an average of 7 to 9 percent in avoidable costs per year;
the exact figure depends entirely on the building. f it a relatively well-performing building already,
it may see lower savings; if it a poor-performing building, it could be much higher,
maybe 15 to 20 percent, says Gayeski, who graduated from MIT Building Technology Program, along with his two cofounders.
Last month, MIT commissioned the software for more than 60 of its own buildings, monitoring more than 7, 000 pieces of equipment over 10 million square feet.
Previously, in a yearlong trial for one MIT building, the software saved MIT $286, 000. Benefits, however, extend beyond financial savings,
Gayeski says. here are people in those buildings: What their quality of life? There are people who work on those buildings.
We can provide them with better information to do their jobs, he says. The software can also help buildings earn additional incentives by participating in utility programs. e have major opportunities in some utility territories,
where energy-efficiency has been incentivized. We can help buildings meet energy-efficiency goals that are significant in many states,
including Massachusetts, says Alex Grace, director of business development for KGS. Other customers include universities, health-care and life-science facilities, schools,
and retail buildings. Equipment-level detection Fault-detection and diagnostics research spans about 50 years with contributions by early KGS advisors
and MIT professors of architecture Les Norford and Leon Glicksman and about a dozen companies now operate in the field.
But KGS, Gayeski says, is one of a few ventures gathering quipment-level data, gathered through various sensors, actuators,
and meters attached to equipment that measure functionality. Clockworks sifts through that massive store of data, measuring temperatures, pressures, flows, set points,
and control commands, among other things. It able to gather a few thousand data points every five minutes
which is a finer level of granularity than meter-level analytics software that may extract,
say, a data point every 15 minutes from a utility meter. hat gives a lot more detail,
a lot more granular information about how things are operating and could be operating better, Gayeski says.
For example, Clockworks may detect specific leaky valves or stuck dampers on air handlers in HVAC units that cause excessive heating or cooling.
To make its analyses accurate, KGS employs what Gayeski calls ass customization of code. The company has code libraries for each type of equipment it works with such as air handlers, chillers,
and boilers that can be tailored to specific equipment that varies greatly from building to building.
This makes Clockworks easily scalable, Gayeski says. But it also helps the software produce rapid, intelligent analytics such as accurate graphs, metrics,
and text that spell out problems clearly. Moreover it helps the software to rapidly equate data with monetary losses. hen we identify that there a fault with the right data,
we can tell people right away this is worth, say, $50 a day or this is worth $1, 000 a day and wee seen $1,
000-a-day faults so that allows facilities managers to prioritize which problems get their attention,
he says. KGS Buildingsfoundation The KGS cofounders met as participants in the MIT entry for the 2007 Solar Decathlon an annual competition where college teams build small-scale, solar-powered homes to display at the National Mall
in Washington. Kleindienst worked on lighting systems while Samouhos and Gayeski worked on mechanical design and energy-modeling.
After the competition, the cofounders started a company with a broad goal of making buildings better through energy savings.
While pursuing their Phds, they toyed with various ideas, such as developing low-cost sensing technology with wireless communication that could be retrofitted on to older equipment.
Seeing building data as an emerging tool for fault-detection and diagnostics, however, they turned to Samouhosphd dissertation,
which focused on building condition monitoring. It came complete with the initial diagnostics codes and a framework for an early KGS module. e all came together anticipating that the building industry was about to change a lot in the way it uses data,
where you take the data, you figure out what not working well, and do something about it,
Gayeski says. t that point, we knew it was ripe to move forward. Throughout 2010, they began trialing software at several locations,
including MIT. They found guidance among the seasoned entrepreneurs at MIT Venture Mentoring Service learning to fail fast,
and often. hat means keep at it, keep adapting and adjusting, and if you get it wrong,
you just fix it and try again, Gayeski says. Today, the company headquartered in Somerville, Mass.
with 16 employees is focusing on expanding its customer base and advancing its software into other applications.
About 180 new buildings were added to Clockworks in the past year; by the end of 2014, KGS projects it could deploy its software to 800 buildings. arger companies are starting to catch on,
Gayeski says. ajor health-care institutions, global pharmaceuticals, universities, and others are starting to see the value
and deciding to take action and wee starting to take off. Liberating data By bringing all this data about building equipment to the cloud, the technology has plugged into the nternet of thingsa concept where objects would be connected, via embedded chips and other methods, to the Internet for inventory and other purposes.
Data on HVAC systems have been connected through building automation for some time. KGS however, can connect that data to cloud-based analytics and extract eally rich informationabout equipment,
Gayeski says. For instance, he says, the startup has quick-response codes like a barcode for each piece of equipment it measures,
so people can read all data associated with it. s more and more devices are connected readily to the Internet,
we may be tapping straight into those, too, Gayeski says. nd that data can be liberated from its local environment to the cloud,
Grace adds. Down the road, as technology to monitor houses such as automated thermostats and other sensors begins to nlock the data in the residential scale,
Gayeski says, GS could adapt over time into that space, as well. o
#The incredible shrinking power brick While laptops continue to shrink in size and weight, the ower bricksthat charge them remain heavy and bulky.
But now, MIT spinout FINSIX has invented an adapter that roughly one-quarter the size and one-sixth the weight of a conventional brick,
and just as efficient. Co-founded by four MIT alumni Vanessa Green MNG 8, MBA 1;
Anthony Sagneri SM 7, Phd 2; George Hwang Phd 0; and Justin Burkhart SM 0 FINSIX has developed the world smallest laptop adapter,
called the Dart. Around 2 1/2 cubic inches in size and weighing around 2 ounces,
the adapter is only slightly larger than an ordinary plug. The Dart runs on novel very high-frequency frequency (VHF) power-conversion technology, co-invented by Sagneri,
that delivers energy more often and in smaller chunks than traditional adapters, ultimately wasting less energy.
It does so by making the adapter switching frequency which transfers energy from the adapter to the battery run 1,
000 times faster. f you can increase that switching frequency, you can reduce the amount of energy that you have to store temporarily in the inductors and capacitors
which make up the bulk size and weight of power bricks during the conversion process, and that yields reduced size,
Sagneri explains. The 65-watt Dart can power most laptops, smartphones, and tablets. By November, FINSIX aims to deliver its first shipment of around 4, 500 Darts to Kickstarter backers and other customers.
Although Dart is FINSIX first consumer product, Green says the company aims to bring VHF technology to wide range of applications.
This could shrink the AC-DC power converters for products such as LED LIGHTS flat-screen TVS, gaming consoles, laptops, electric bikes,
and air conditioners, while reducing the cost of manufacturing. The technology could also help reduce energy consumption with more ubiquitous power conversion,
Sagneri says. ee not really an adapter company; wee creating the commercially enabled technology to allow VHF power converters to become a significant portion of the market,
Sagneri says. he idea is to help people reimagine the power delivery in their systems.
In places where that a bottleneck which it continues to be, as devices get more dense and capable it helps the rest of technology progress.
Under the tutelage of David Perreault, an MIT professor of electrical engineering, Sagneri helped develop a novel circuit that executes power conversion at very high frequency 30 to 300 megahertz
while maintaining efficiency. When FINSIX first licensed this technology the company set its sights on shrinking power converters for LED LIGHTS.
About a year later, when the AC-DC technology was ready, the company started focusing on laptop adapters.
In traditional adapters, an array of switches flip to one state and take in AC voltage from a wall outlet,
where it then stored in inductors and capacitors and converted to DC voltage. The switches then flip to another state to deliver small chunks of the DC voltage to the battery,
before returning to their original state. Think of the electricity as water being transferred via bucket from a full tank to an empty tank
says Sagneri. In that analogy, the bucket is the adapter that collects the water (electricity) from a full tank (outlet) and dumps it into an empty tank (laptop battery.
f you want to deliver, say, a gallon of water per minute from the full tank to the empty tank,
with conventional adapters youe dipping a one-gallon bucket into the full tank once a minute,
Sagneri says. ee delivering that same amount of water, in that same time frame, but 1, 000 times faster.
So our bucket shrinks from one gallon to one-thousandth of a gallon. But each switch cycle burns energy as heat.
Switching 1, 000 times faster in a typical converter, therefore, means 1, 000 times more energy wasted.
So the circuit uses resonance techniques (modifying how energy oscillates between inductors and capacitors) to minimize energy loss,
meaning the switches turn on and off more efficiently at higher frequencies. MIT: boon to us-Today, FINSIX which has raised more than $7 million in funding
and hired 20 employees operates out of Menlo Park, Calif, . and is rigorously testing its commercial product
and rounding up manufacturers. But its story began at MIT in 2010. Green, as a student in the MIT Sloan School of management, was looking for technology to commercialize.
At the same time, Sagneri, Hwang, and Burkhart were electrical engineering and computer science students who were excited to start a company.
Around 2010, their interests merged in MIT Sloan 15.390 (New Enterprises), a course where students pitch business ideas
and the class chooses ideas to pursue. Sagneri VHF power-conversion technology wasn chosen. But Green saw potential. was interested in working on something that had real technology behind it,
she says. The four-person founding team began building FINSIX (then Onchip Power) with mentorship from seasoned entrepreneurs in the Martin Trust Center for MIT Entrepreneurship and MIT Venture Mentoring Service.
IT ecosystem was a boon to us, Sagneri says. To grow FINSIX, Green who won MIT Patrick J. Mcgovern 9 Entrepreneurship Award in 2011 harkened back to her days in 15.366 (Energy Ventures),
where students from across departments plan businesses around clean technologies. Throughout the class, she says, teams learn the crucial steps of gathering customer feedback, meeting technological milestones,
working through funding stages, and continuously returning to the customer. oing through the process there showed
me the steps you need to take if you want to commercialize technology, Green says. e repeated a lot of those steps as we put together the foundation for Onchip, now FINSIX.
For me, a lot of the entrepreneurship process was learned though my MIT education. Moving forward, FINSIX is looking at getting its first product, Dart, into the market and developing higher-and lower-power products to suit customer needs u
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