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Hackers Could Use Connected Cars to Gridlock Whole Cities

Hackers Could Use Connected Cars to Gridlock Whole Cities

In the year 2026, at rush hour, your self-driving car abruptly shuts down right where it blocks traffic. You climb out to see gridlock down every street in view, then a news alert on your watch tells you that hackers have paralyzed all Manhattan traffic by randomly stranding internet-connected cars.

Flashback to July 2019, the dawn of autonomous vehicles and other connected cars, and physicists at the Georgia Institute of Technology and Multiscale Systems, Inc. have applied physics in a new study to simulate what it would take for future hackers to wreak exactly this widespread havoc by randomly stranding these cars. The researchers want to expand the current discussion on automotive cybersecurity, which mainly focuses on hacks that could crash one car or run over one pedestrian, to include potential mass mayhem.

They warn that even with increasingly tighter cyber defenses, the amount of data breached has soared in the past four years, but objects becoming hackable can convert the rising cyber threat into a potential physical menace.

“Unlike most of the data breaches we hear about, hacked cars have physical consequences,” said Peter Yunker, who co-led the study and is an assistant professor in Georgia Tech’s School of Physics.

It may not be that hard for state, terroristic, or mischievous actors to commandeer parts of the internet of things, including cars.

“With cars, one of the worrying things is that currently there is effectively one central computing system, and a lot runs through it. You don’t necessarily have separate systems to run your car and run your satellite radio. If you can get into one, you may be able to get into the other,” said Jesse Silverberg of Multiscale Systems, Inc., who co-led the study with Yunker

Freezing traffic solid

In simulations of hacking internet-connected cars, the researchers froze traffic in Manhattan nearly solid, and it would not even take that to wreak havoc. Here are their results, and the numbers are conservative for reasons mentioned below.

“Randomly stalling 20 percent of cars during rush hour would mean total traffic freeze. At 20 percent, the city has been broken up into small islands, where you may be able to inch around a few blocks, but no one would be able to move across town,” said David Yanni, a graduate research assistant in Yunker’s lab.

Not all cars on the road would have to be connected, just enough for hackers to stall 20 percent of all cars on the road. For example, if 40 percent of all cars on the road were connected, hacking half would suffice.

Hacking 10 percent of all cars at rush hour would debilitate traffic enough to prevent emergency vehicles from expediently cutting through traffic that is inching along citywide. The same thing would happen with a 20 percent hack during intermediate daytime traffic.

The researchers’ results appear in the journal Physical Review E on July 20, 2019. The study is not embargoed.

It could take less

For the city to be safe, hacking damage would have to be below that. In other cities, things could be worse.

“Manhattan has a nice grid, and that makes traffic more efficient. Looking at cities without large grids like Atlanta, Boston, or Los Angeles, and we think hackers could do worse harm because a grid makes you more robust with redundancies to get to the same places down many different routes,” Yunker said.

The researchers left out factors that would likely worsen hacking damage, thus a real-world hack may require stalling even fewer cars to shut down Manhattan.

“I want to emphasize that we only considered static situations – if roads are blocked or not blocked. In many cases, blocked roads spill over traffic into other roads, which we also did not include. If we were to factor in these other things, the number of cars you’d have to stall would likely drop down significantly,” Yunker said.

The researchers also did not factor in ensuing public panic nor car occupants becoming pedestrians that would further block streets or cause accidents. Nor did they consider hacks that would target cars at locations that maximize trouble.

They also stress that they are not cybersecurity experts, nor are they saying anything about the likelihood of someone carrying out such a hack. They simply want to give security experts a calculable idea of the scale of a hack that would shut a city down.

The researchers do have some general ideas of how to reduce the potential damage.

“Split up the digital network influencing the cars to make it impossible to access too many cars through one network,” said lead author Skanka Vivek, a postdoctoral researcher in Yunker’s lab. “If you could also make sure that cars next to each other can’t be hacked at the same time that would decrease the risk of them blocking off traffic together.”

Traffic jams as physics

Yunker researches in soft matter physics, which looks at how constituent parts – in this case, connected cars – act as one whole physical phenomenon. The research team analyzed the movements of cars on streets with varying numbers of lanes, including how they get around stalled vehicles and found they could apply a physics approach to what they observed.

“Whether traffic is halted or not can be explained by classic percolation theory used in many different fields of physics and mathematics,” Yunker said.

Percolation theory is often used in materials science to determine if a desirable quality like a specific rigidity will spread throughout a material to make the final product uniformly stable. In this case, stalled cars spread to make formerly flowing streets rigid and stuck.

The shut streets would be only those in which hacked cars have cut off all lanes or in which they have become hindrances that other cars can’t maneuver around and do not include streets where hacked cars still allow traffic flow.

The researchers chose Manhattan for their simulations because a lot of data was available on that city’s traffic patterns.

Materials provided by Georgia Institute of Technology

Peanut Plant’s “Chemical Breath” Could Give Clues to Drought and Other Stresses

Peanut Plant’s “Chemical Breath” Could Give Clues to Drought and Other Stresses

Peanut growers could someday identify emerging threats such as drought, pests or disease by testing a plant’s “chemical breath.”

From dawn to dusk, peanut plants emit volatile organic compounds (VOCs) that vary in types and patterns depending on how they respond to various stresses. Growers typically rely on indirect monitoring methods such as soil moisture testing to assess the health of plants in their fields. But directly testing stress response could be faster more accurate and offer a wider range of diagnoses. Now scientists are working on gas-collection devices that growers could deploy in fields or on plants.

“We want to learn the best ways to detect and measure gases that could correlate to various plant conditions such as drought,” said Wayne Daley, associate division chief and principal research engineer with the Agricultural Technology Research Program at the Georgia Tech Research Institute(GTRI).

About 1.67 million acres of peanuts were harvested in the U.S. in 2017, according to the U.S. Department of Agriculture — 160,000 in Florida and 850,000 in Georgia. Peanuts are a $2.2 billion crop in Georgia, accounting for 23 percent of the state’s row and forage crop income, according to the Georgia Peanut Commission.

Collecting air samples from peanut plants

A GTRI researcher installs air sampling equipment used to collect volatile organic compounds from peanut plants. Analyzing the compounds could indicate when the plants are under stress, allowing farmers to adjust growing conditions. (Photo: Branden Camp, Georgia Tech)

Daley and his co-investigators are collaborating with Diane Rowland, Barry Tillman and Alina Zare, all affiliated faculty of the University of Florida’s Center for Stress Resilient Agriculture, to identify and design collection methods for VOCs in an outdoor field site, an environmental chamber and a greenhouse in Florida. The GTRI team includes chemists Judy Song and Dan Sabo and data scientists Olga Kemenova and Milad Navaei.

“This type of advanced technology is what is critically needed for our growers to remain economically viable,” said Rowland, professor of physiology at the University of Florida. “Resource use efficiency in farming, including rapidly responding to counteract stress events such as drought, is the key not only to environmental stewardship, but also for remaining profitable under rising input costs.”

Still, detecting relevant gases in the field remains a giant challenge.

“Peanut plants release VOCs at very low concentrations that are difficult to measure,” said Daley. “We want to learn which VOCs are significant and tell us about stresses that are of interest to growers.” In a previous study, Daley and other GTRI scientists learned that VOC signatures are different among peanut plants at various degrees of drought intensity.

During the 2017 growing season, GTRI researchers placed glass rods coated with gas-absorbent material near peanut plants. The rods were taken to the lab and excited to release the absorbed gases, which were identified and measured. But a field site is a complex environment with many confounding factors.

Now the researchers are evaluating this gas-measurement technique to study peanut plants grown in controlled lab conditions.

During the 2017 growing season, researchers from University of Florida collected the field data from peanut plants using polydimethylsiloxane-coated stir bars (Twisters). The collected gases were sent to GTRI for identification and analysis using a thermal desorption unit.

Now the researchers are evaluating this gas-measurement technique to study peanut plants grown in controlled lab conditions.

A peanut plant’s seasonal growth stages affect the amounts and types of VOCs it releases. Even the time of day affects these emissions.

“We are building an environmental chamber in which we can mimic the humidity, lighting, and nutrients of a natural field on a Florida day from the morning to evening with appropriate humidity,” said Daley. “This is the first step to test and evaluate the gas measurement technique in controlled conditions. Once we know more about its performance and how to apply it, then we’ll take it to the University of Florida to be studied with plants in a greenhouse.”

The team is developing a baseline of peanut VOC “families” that could be identified in the environmental chamber. Each peanut stressor also could be associated with a distinct family of VOCs. For instance, researchers could simulate a drought in the chamber to study the associated VOCs. But there may be background families of VOCs that compete with or confuse a drought gas test.

“We need to understand how the peanut plant responds to both health and stress conditions to be able to fully utilize VOCs for drought detection” said Sabo, a GTRI research scientist.

“We are investigating how interference gases compete for space on the absorbent material,” said Song, a GTRI senior research engineer. “The experiment in the environmental chamber will be able to help us gain an understanding of how these interference gases and stressed-based VOCs interact and interfere with one another. With this knowledge we will be able to make accurate and meaningful measurements.”

Once researchers understand the ambient complexity of an outdoor peanut field, they could develop and refine a specialized gas test for peanut drought stress indicators, which could help farmers improve irrigation scheduling or prevent aflatoxins, which are potential carcinogens.

“You could probably develop and instrument the field with reliable compact sensors that allow for quick and convenient VOC collection and assessment,” said Daley. “Or we could envision robots manually taking samples.”

Materials provided by Georgia Institute of Technology

Instability in Antarctic Ice Projected to Make Sea Level Rise Rapidly

Instability in Antarctic Ice Projected to Make Sea Level Rise Rapidly

Images of vanishing Arctic ice and mountain glaciers are jarring, but their potential contributions to sea level rise are no match for Antarctica’s, even if receding southern ice is less eye-catching. Now, a study says that instability hidden within Antarctic ice is likely to accelerate its flow into the ocean and push sea level up at a more rapid pace than previously expected.

In the last six years, five closely observed Antarctic glaciers have doubled their rate of ice loss, according to the National Science Foundation. At least one, Thwaites Glacier, modeled for the new study, will likely succumb to this instability, a volatile process that pushes ice into the ocean fast.

How much ice the glacier will shed in coming 50 to 800 years can’t exactly be projected due to unpredictable fluctuations in climate and the need for more data. But researchers at the Georgia Institute of Technology, NASA Jet Propulsion Laboratory, and the University of Washington have factored the instability into 500 ice flow simulations for Thwaites with refined calculations.

The scenarios diverged strongly from each other but together pointed to the eventual triggering of the instability, which will be described in the question and answer section below. Even if global warming were to later stop, the instability would keep pushing ice out to sea at an enormously accelerated rate over the coming centuries.

And this is if ice melt due to warming oceans does not get worse than it is today. The study went with present-day ice melt rates because the researchers were interested in the instability factor in itself.

Glacier tipping point

“If you trigger this instability, you don’t need to continue to force the ice sheet by cranking up temperatures. It will keep going by itself, and that’s the worry,” said Alex Robel, who led the study and is an assistant professor in Georgia Tech’s School of Earth and Atmospheric Sciences. “Climate variations will still be important after that tipping point because they will determine how fast the ice will move.”

“After reaching the tipping point, Thwaites Glacier could lose all of its ice in a period of 150 years. That would make for a sea level rise of about half a meter (1.64 feet),” said NASA JPL scientist Helene Seroussi, who collaborated on the study. For comparison, current sea level is 20 cm (nearly 8 inches) above pre-global warming levels and is blamed for increased coastal flooding.

The researchers published their study in the journal the Proceedings of the National Academy of Sciences on Monday, July 8, 2019. The research was funded by the National Science Foundation and NASA.

The study also showed that the instability makes forecasting more uncertain, leading to the broad spread of scenarios. This is particularly relevant to the challenge of engineering against flood dangers.

“You want to engineer critical infrastructure to be resistant against the upper bound of potential sea level scenarios a hundred years from now,” Robel said. “It can mean building your water treatment plants and nuclear reactors for the absolute worst-case scenario, which could be two or three feet of sea level rise from Thwaites Glacier alone, so it’s a huge difference.”


Why is the Antarctic ice the big driver of sea level rise?

Understanding the instability is easier with this background information.

Arctic sea ice is already floating in water. Readers will likely remember that 90% of an iceberg’s mass is underwater and that when its ice melts, the volume shrinks, resulting in no change in sea level.

But when ice masses long supported by land, like mountain glaciers, melt, the water that ends up in the ocean adds to sea level. Antarctica holds the most land-supported ice, even if the bulk of that land is seabed holding up just part of the ice’s mass, while water holds up part of it. Also, Antarctica is an ice leviathan.

“There’s almost eight times as much ice in the Antarctic ice sheet as there is in the Greenland ice sheet and 50 times as much as in all the mountain glaciers in the world,” Robel said.

What is that ‘instability’ underneath the ice?

The line between where the ice sheet rests on the seafloor and where it extends over water is called the grounding line. In spots where the bedrock underneath the ice behind the grounding line slopes down, deepening as it moves inland, the instability can kick in.

That would look like this: On deeper beds, ice moves faster because water is giving it a little more lift, to begin with, then warmer ocean water can hollow out the bottom of the ice, adding water to the ocean. But, more importantly, the ice above the hollow loses land contact and flows faster out to sea.

“Once ice is past the grounding line and only over water, it’s contributing to sea level because buoyancy is holding it up more than it was before,” Robel said. “Ice flows out into the floating ice shelf and melts or breaks off as icebergs.”

“The process becomes self-perpetuating,” Seroussi said, describing why it is called “instability.”

How did the researchers integrate instability into sea level forecasting?

The researchers borrowed math from statistical physics that calculates what haphazard influences do to predictability in a physical system, like ice flow, acted upon by outside forces, like temperature changes. They applied the math to data-packed simulations of possible future fates of Thwaites Glacier, located in West Antarctica, where ice loss is most.

They made an added surprising discovery. Normally, when climate conditions fluctuate strongly, Antarctic ice evens out the effects. Ice flow may increase but gradually, not wildly, but the instability produced the opposite effect in the simulations.

“The system didn’t damp out the fluctuations, it actually amplified them. It increased the chances of rapid ice loss,” Robel said.

How rapid is ‘rapid’ sea level rise and when will we feel it?

The study’s time scale was centuries, as is common for sea level studies. In the simulations, Thwaites Glacier colossal ice loss kicked in after 600 years, but it could come sooner if oceans warm and as the instability reveals more of its secrets.

“It could happen in the next 200 to 600 years. It depends on the bedrock topography under the ice, and we don’t know it in great detail yet,” Seroussi said.

So far, Antarctica and Greenland have lost a small fraction of their ice, but already, shoreline infrastructures face challenges from increased tidal flooding and storm surges. Sea level is expected to rise by up to two feet by the end of this century.

For about 2,000 years until the late 1800s, sea level held steady, then it began climbing, according to the Smithsonian Institution. The annual rate of sea level rise has roughly doubled since 1990.

Materials provided by Georgia Institute of Technology