Autonomous Vehicles by Rishabh Shukla

DECCAN HERALD 3

Tuesday, December 6, 2016

Spectrum science

MILKY WAY’S NEW STARS

The discovery of a new family of stars, known as globular clusters, in the Milky Way, provides new insights into how it was formed in its early stages.

What drives autonomous vehicles? macHine LearninG rishabh Shukla unravels the science behind the functioning of self-driven vehicles, while also tracing research advances that helped materialise the concept

BRISK WORKOUT One should aim for at least 150 minutes of moderate exercise per week. REPRESENTATIVE IMAGE

born to move

HumanbioLoGy recent research indicates that we might be fighting thousands of years of evolutionary history and the best interests of our bodies when we sit all day, reports Gretchen reynolds

re we fighting thousands of years of evolutionary history and the best interests of our bodies when we sit all day? That question is at the core of a fascinating new study of the daily lives and cardiovascular health of a modern tribe of hunter-gatherers. The findings strongly suggest that we are born to be in motion, with health consequences when we are not. Evolutionary biologists have long believed that the basic structure of human bodies and genomes were set tens of thousands of years ago, when we were hunter-gatherers. The hunter-gatherers from that time who were most adept at following game or finding tubers won the baby-making lottery and passed along their genes to us, their descendants. But we no longer live in a hunting and gathering world. Mostly, we live in offices and in front of screens, where we sit and have food brought to us, creating a fundamental mismatch between the conditions that moulded our bodies and those that we inhabit. The health consequences of this mismatch are well-established. Many scientists have pointed out that the easy availability of food creates an ‘obesogenic’ world, in which we easily gain weight and develop related health problems. There also has been considerable research linking sedentary lifestyles with health concerns. But we have not really known just how much physical activity may be natural

SNIPPETS How good is a bad night’s sleep?

s a night’s sleep physiologically beneficial even if it includes emotionally disturbing nightmares? Almost certainly yes, said Dr Neomi Shah, a specialist at the Mount Sinai Integrative Sleep Centre in New York, USA. Despite the problems nightmares can cause, sleeping and having them is better than not sleeping, research suggests. Nightmares can make it difficult to sleep and interfere with daytime functioning, but physiological indicators of sleep patterns and quality do not differ in people who have nightmares, Dr Neomi said. Frequent long, distressing and vivid dreams often wake people and cause problems like insomnia and poor sleep quality, she said. Research has also

for us. The fossil record is evocative but inexact, unable to tell us precisely how our ancestors lived, while most past anthropological studies of living huntergatherers have been observational, meaning that researchers have estimated activity patterns. But estimates can be wrong. So, for the new study, which was published last month in the American Journal of Human Biology, researchers from Yale University, the University of Arizona, USA and other institutions decided to bring high-tech rigour to their ongoing examination of a group of African hunter-gatherers. For many years, the scientists had been studying and tagging along on hunts with the Hadza, a tribe in Tanzania that lives by subsistence hunting and foraging for berries, honey, baobab fruit and tubers. As part of past research, the scientists had measured the men’s and women’s blood pressures, lipids and other markers of cardiovascular health. They now asked some of the tribespeople if they would wear heart-rate monitors around their chests. The scientists focused on heart rates since most modern recommendations about exercise involve intensity. We are told that we should aim for at least 150 minutes per week of moderate exercise or 75 minutes of vigorous exercise. The simplest way to determine exercise intensity is with heart rate. By most definitions, moderate exercise raises someone’s heart rate to between 55 and 69% of that person’s maximum heart rate, while vigorous exercise raises it to between 70 and 89%. Maximum heart rate can be calculated from a formula based on age.

many scientists have pointed out that the easy availability of food creates an ‘obesogenic’ world, in which we easily gain weight and develop health problems.

Enviable heart health Forty-six of the tribes people, ranging in age from young adults to people in their 70s, agreed to participate, donning a chest strap for up to two weeks during different seasons of the year while they went about their daily lives. The researchers then gathered the heart rate data

and used it to determine how much and at what intensity the tribes people had moved. They moved a lot, the data proved, typically being active for more than two hours every day. The men would walk briskly in search of various game animals off and on throughout most days. The women would find, dig up, heft and prepare fruits, vegetables and other foods. The vast majority of this activity was moderate. The tribes people rarely ran or were otherwise vigorously active, says Brian Wood, an assistant professor of anthropology at Yale and co-author of the study. They remained active, too, well into middle age and beyond, with those tribes people in their 70s moving as much as or even more than the young. Perhaps most important, the tribes people also had enviable heart health. The scientists found that the Hadza typically showed low blood pressure and excellent cholesterol profiles across their life spans, even deep into old age. Some of this robust, lifelong cardiovascular health is no doubt a result of diet, Brian says, but the data intimate that the Hadzas’ active lifestyle, consisting of plenty of walking, lifting and generally being up and doing, helps protect their hearts against disease. The underlying lesson of the study, however, is not that we should all renounce our jobs and homes “and become hunter-gatherers for the sake of our hearts,” he says. The Hadzas’ lives remain difficult and chancy, he points out, with pronounced risks for untreated infections and illnesses, accidental deaths and no access to dental care. The more nuanced but still potent takeaway of the new study, says David Raichlen, an anthropologist and exercise scientist at the University of Arizona who led the study, is that “human bodies likely evolved to need and respond to the kind of physiological demands”the Hadza still undergo on most days. Our bodies, and in particular our hearts, want to be worked, at least moderately, he says. When they are not, when our pulse rarely rises, pathology may set in. So move, he says, and preferably often, since the need for activity seems to be built into our bones and hearts and being. The New York Times

consistently demonstrated that nightmares can harm general well-being, affect mood and elevate stress. Some studies suggest there are measurable sleep problems for people who have nightmares, while others show no difference. The studies that show such a link found that people who woke up stayed awake longer and that certain stages of sleep did not last as long. But people in those studies who had nightmares also had longer periods of rapid eye movement, or REM, sleep, when most dreaming occurs. A weakness of these studies is that they were not conducted in the subjects’ normal sleeping environment. A more recent study in such an environment found no WELL-BEING Sleep with disturbing nightmares is better than no sleep, researchers differences in so-called sleep architec- say. PHOTO CREDIT: VICTORIA ROBERTS/NYT ture, sleep-cycle and REM durations, or sleep patterns for just the nights with dreds of chemicals across its surface. Scinightmares. entists recently swabbed the hands of 39 Therefore, Dr Neomi said, despite uppeople, and their phones, producing hunsetting nightmares, “sleep architecture dreds of chemical samples. Based on the appears to be preserved, and subjects our phone is pretty much a high-tech compounds on both hands and phones, with frequent nightmares are likely debucket of germs. Thousands of mi- the researchers were able to make inferriving the physiological benefits of sleep.” croscopic bugs crawl around on its ences about each person’s lifestyle. C Claiborne Ray surface. Your hands have smeared hunOne day, the technique might be used

Getting to know you from your phone

magine calling a taxi using one of the cab aggregating apps and you find a ‘ghost’ driver. If you think it is a page out of a science fiction, think again as Autonomous Vehicles (AV) or self-driving vehicles are already in operation in some cities of the world on a small scale. For instance, nuTonomy, a Singapore-based startup, became the world’s first company to test a self-driving taxi service in Singapore on August 25, 2016. Just a few weeks later, on September 14, 2016, Uber launched its first self-driving taxi fleet in Pittsburgh, Pennsylvania, USA. You will hear more such news in the days to come as AVs are expected to replace the conventional driver-driven vehicles by 2020 or sooner. A study by Business Insider, a news website, estimates about 10 million self-driving cars to be on roads by 2020. The market for AV is big and presently has automobile giants like BMW, Volkswagen and Tesla racing against each other to transfer the driving control from humans to computers. Google’s ambitious Self Driving Car project, developed in collaborationwithStanfordUniversity,was a game changer and won the 2006 US Defense Advanced Research Projects Agency (DARPA) Grand challenge. While companies like Tesla are developing a computerbased driver assistance system to help drivers avoid accidents, others are relying on the concept of a fully automated car.

blocking its path. Such crashes have been termed as ‘learning experience’. So, what actually drives these cars? The brain of the AVs is the algorithms that are programmed to function in a specific way based on Artificial Intelligence and Machine Learning. These algorithms, much like our brain, react based on the surrounding conditions. A self-driving car uses a GPS to know its location, a RADAR to detect obstacles, a laser ranging system to map the three-dimensional surrounding and a camera to identify traffic lights and signs, recognise pedestrians and monitor other vehicles on the road. There are also sensors that track weather and road conditions. All the data collected from the cameras, GPS, RADARs and sensors are fed to an on-board computer which manoeuvres the car to its destination, avoiding people and other vehicles on the way. However, for rare events like a plastic bag blowing down the road, the computer has to rely on the ‘knowledge’ developed through test drives. This is where the learning comes into play. Based on the inputs and the learning history, the computer decides the course of action and thus, making the ride safe and reliable. The advantages of AVs do not stop at that. AVs can then be sold as a service, just like cabs, and no one would ever want to own a car! What’s more is that these vehicles will also be eco-friendly with a five to 15% reduction in fuel consumption and a Algorithm-based comparable reduction in CO2 emissions. The quest for AVs started with the need However, not everything is rosy at the moto fix the least reliable part of the car — ment with self-driving vehicles. the driver. A look at the statistics can emphasise the need for this — over 1.4 lakh A cause for concern? people are killed in road accidents every Though there is a push by several governyear in India and about 93% of these acci- ments and industries for these vehicles, dents are caused due to human error. there are some ethical, legal and security Computers, unlike humans, are near per- issuesthatneedtobeaddressed.Situations fect drivers who respond quickly. where a car has to decide between the lives Variousexperimentshavebeenconduct- of passengers and the person who is in ed on automating cars since the 1920s and front are still unresolved and need to be the first truly autonomous car was realised debated widely. Legal issues concerning in the 1980s at the Carnegie Mellon Uni- accidents involving AVs as who should be versity’s Navlab, USA. Research picked up blamed by law need to be charted out. pace in the recent decade with the advent Thereisalsoawidespreadskepticismabout of improved machine learning techniques, hackerstakingoverthecontrolwhilesomebetter computing hardware and software, one is on board. and more accurate sensor technologies. As a ray of hope, some of steps in the However, there are reports of collisions right direction is being taken with the US of such cars that have been termed as ei- Federalgovernmentdraftingguidelinesfor ther a software failure or a misunderstand- automated vehicles. At this point, not ing. Google has confirmed that there have everyone might know how AVs might been 12 collisions of its self-driving cars as change their life, but there is a sense of of 2015 with just one resulting in injuries excitement. But can a computer compete to passengers in the car. On 14 February, against humans? Only time can tell! 2016, a Google self-driving car struck a (The author is with Gubbi Labs, a bus when it attempted to avoid sandbags Bengaluru-based research collective)

in criminal investigations to narrow down a suspect pool when DNA or fingerprint evidence doesn’t yield a match, according to new research. But critics argue it’s not ready for such tasks and worry that investigators might push courts to admit evidence based on potentially inaccurate inferences. For the moment, your bodily secrets are safe with your phone.

Joanna Klein

Lower status affects monkey’s immunity

In humans, chronic inflammation has been associated with chronic stress and is suspected of increasing a person’s risk for illnesses from heart disease to Alzheimer’s. The new findings add support to the idea that the chronic stress that attends lower status may play a role in predisposing people to illness, the researchers said. Erica Goode

Large ice sheet found

n ice sheet holding more water than Lake Superior may slake the thirst of future astronauts living on Mars. Using radar soundings from NASA’s Mars Reconnaissance Orbiter spacecraft, scientists probed what lies in Utopia Planitia, a 2,000-mile-wide basin within an ancient impact crater. What they found is an underground ice deposit ranging in thickness from 260 to 560 feet, and covering an area larger than New Mexico, USA. The ice is fairly pure — at least 50% frozen water — with dirt, rocks and porous empty spaces mixed in, researchers believe.

ocial class is one of the most powerful predictors of health, more powerful than genes, smoking, alcohol intake or other health risks. But scientists do not know for sure whether lower social status causes people to end up sicker, or whether being less healthy leads to lower social status. Now, researchers report that for 45 female rhesus monkeys, their position in the dominance hierarchy altered the functioningoftheirimmunesystems.Thelower a female monkey’s rank, the more inflam- Kenneth Chang mation-related genes were turned on. The New York Times