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| SCIENCE & TECHNOLOGY |
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New
technology can track movement behind walls Prof Yash
Pal This
Universe |
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As we type, so we speak WHERE once speech was the driving force behind language change, we are moving into an era where writing — or, more precisely, the act of typing on to screens — is a dominant form of verbal interaction. And this has brought with it an accelerating transformation of not only the words we use, but how we read each others’ lives. Consider the emoticon: a human face sketched from three punctuation marks. Born during the course of an early online discussion in 1982, courtesy of computer scientist Scott Fahlman, it addressed one central absence of onscreen words: a human face able to indicate emotional tone. Fahlman coined two basic expressions — “happy” and “sad” (signalling “joking” and “not joking”, respectively) — but further variations almost immediately began to spring up, stretching today into many thousands. Aside from bewildering ingenuity, one thing all of these share is that they are unpronounceable: symbols aimed at the eye rather than at the ear, like an emotionally enriched layer of punctuation. There’s nothing inherently new about such effects. In 1925, the American Professor George Krapp coined the phrase “eye dialect” to describe the use of selected mis-spellings in fiction signalling a character’s accent without requiring a phonetic rendering of their speech. Mark Twain, for example, used just a handful of spelling variations to convey the colourful speech of his character Jim in Huckleberry Finn (1884), such as “ben” for been and “wuz” for was. The “z” of Twain’s wuz might have a strangely contemporary feel to some readers, courtesy of the so-called “Internet z” – a common typo for the letter “s” that has taken on a new life in typed terms such as “lulz”, denoting an anarchistic flavour of online amusement via the mangling of the acronym “laughs out loud” (LOL). While he was a master of visual verbal effects, Twain wouldn’t have recognised the strange reversal of traditional relationships between written and spoken language that something like LOL represents. For, where once speech came first and writing gradually formalised its eccentricities, we’re now typing some terms and only then learning to speak them. LOL itself features increasingly in speech (either spelt out or pronounced to rhyme with “doll”) together with its partner in crime, OMG (Oh My God!), while some of the more eccentric typo-inspired terms used in online games (to “pwn” someone, meaning to subject them to a humiliating defeat) can’t even be said out loud. And if that lies outside your experience, consider the familiarity with which almost all of us now say “dot com” or talk about a “dotcom” business: a web-induced articulation of punctuation that would have inconceivable in any other era. These may sound like niche preoccupations but, in the past few years, the rise of social media has put what you might call “conversation without speech” at the centre of millions of lives. Every single day sees more than 100 billion emails and 300 million tweets sent. Video, audio and images are increasingly common, too, with more than 72 hours of new video uploaded to YouTube every minute. Yet, almost all our onscreen exchanges still begin and end with words, from comments and status updates to typed search queries and the text message. There’s something magnificent about our capacity for cramming emotional shading into even the most constricted of verbal arenas, and making them our own. From text messages with more punctuation appended than most standard paragraphs to tweets with startlingly elaborate subtexts spelled out via hash tags (#gently-selfmocking), our creativity knows few bounds — together with our ability to read between the lines and convert even the unlikeliest sequence of 140 characters into a human story. Similarly, the democratisation of written words is an astonishing thing, not least because it gifts permanence to so much that has historically been lost — and supplants those speaking on others’ behalf with an opportunity to directly encounter every individual’s words. Yet there are hazards and seductions within our ingenuity. As writers, our words belong to the world rather than simply to us, and they can be both read and used in ways we cannot foresee — not to mention aggregated, shared, copied and analysed for far longer than we ourselves may exist. Then, too, there’s the fact that we cannot see or know what the faces behind typed words are actually doing; or what the grand performance of social-media selves conceals as well as reveals. We are, in this sense, vulnerable precisely because of our lavish linguistic talents. We cannot help but read our own meanings into everything we see, forgetting the breadth of the gulf between words and world. “The man who does not read,” Twain once wrote, “has no advantage over the man who cannot read.” What might he have made, though, of the man who only reads, or does not know how to listen? Professionally and personally, we live in an age where the messy self-exposure of speech — of even a conversation by phone or Skype — can seem at once too self-exposing and ephemeral to be useful. Onscreen, typing, the world seems clean and comprehensible; ripe for copying, pasting, sorting and — if necessary — for the most careful construction of even the most spontaneous-seeming quip. We have never been more privileged as readers and writers, or more finely attuned to the subtexts that can lurk within even a single letter. Yet conversation is an art that must not be supplanted, not least because it reminds us of what the screen cannot say; and of the constant fiction between what is thought, written and understood, and whatever truths lie behind these. — The Independent
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New technology can track movement behind walls SCIENTISTS are developing a new technology that could give us ‘X-ray’ vision with the ability to track moving humans hiding in closed rooms or behind walls. Researchers at Massachusetts Institute of Technology’s Computer Science and Artificial Intelligence Laboratory are using low-cost Wi-Fi technology to develop the system that spots movement of people in rooms or behind walls. “We wanted to create a device that is low-power, portable and simple enough for anyone to use, to give people the ability to see through walls and closed doors,” said Dina Katabi, a Professor in MIT’s Department of Electrical Engineering and Computer Science. Researchers have long attempted to build a device capable of seeing people through walls. However, previous efforts to develop such a system have involved the use of expensive and bulky radar technology that uses a part of the electromagnetic spectrum only available to the military. The new system, called “Wi-Vi”, is based on a concept similar to radar and sonar imaging. But in contrast to radar and sonar, it transmits a low-power Wi-Fi signal and uses its reflections to track moving humans. It can do so even if the humans are in closed rooms or hiding behind a wall. As a Wi-Fi signal is transmitted at a wall, a portion of the signal penetrates through it, reflecting off any humans on the other side. However, only a tiny fraction of the signal makes it through to the other room, with the rest being reflected by the wall, or by other objects. “So, we had to come up with a technology that could cancel out all these other reflections, and keep only those from the moving human body,” Katabi said. To do this, the system uses two transmit antennas and a single receiver. The two antennas transmit almost identical signals, except that the signal from the second receiver is the inverse of the first. As a result, the two signals interfere with each other in such a way as to cancel each other out. Since any static objects that the signals hit — including the wall — create identical reflections, they too are cancelled out by this nulling effect. “In this way, only those reflections that change between the two signals, such as those from a moving object, arrive back at the receiver,” researcher Fadel Adib said. “So, if the person moves behind the wall, all reflections from static objects are cancelled out, and the only thing registered by the device is the moving human,” Adib added. — PTI
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This Universe According to Newton’s Third Law of Motion, to every action there is equal and opposite reaction. When a rocket moves in the air, the thrust produced by its engine forces the air below it downwards and so the air pushes the rocket upwards. Since space is supposed to be nothing but vacuum, how does a rocket move in it? What you say is somewhat confusing. The rocket is pushed up by the thrust provided by the exhaust gases of the rocket. The engine is in fact this exhaust. This does not need the atmospheric air. The exhaust gases are produced by the rocket fuel, which includes oxygen in some form or other. You can have rockets for which part of the oxidiser is scooped up from the atmosphere, but while accelerating in vacuum the thrust is provided essentially through burning of the stuff carried by the rocket. Can water remain in liquid state at zero degree Celsius? Yes, the state of water also depends on pressure. You can check it yourself. Take a block of ice, hang a wire around this block and let this wire be loaded down by a hanging weight. You will find that the wire melts the ice under it slowly and after a while, it comes out from below the ice block. The pressure of the wire on the ice under it makes it melt, and the melted water will come to the top of the wire and freeze. This spectacular observation clearly shows that the freezing temperature of water is lowered under pressure. Readers can e-mail questions to Prof Yash Pal at palyash.pal@gmail.com
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Next Mars mission should search for past microbial life: Panel CAPE CANAVERAL, Florida: NASA’s next mission to Mars should look for past microbial life and collect samples to eventually bring back to Earth, a science advisory group said. The US space agency expects to spend about $1.5 billion, plus launch costs, on a mission to follow the ongoing Mars rover Curiosity, which is scouting an ancient impact crater for habitats that could have supported microbial life. Earth’s wounds heal faster after quakes than thought WASHINGTON: The ground fractures along fault lines on the Earth’s surface due to earthquakes appear to heal faster than previously thought, a new study has found. Chinese researchers along with representatives from the US and Japan reported on data found by boring holes along the fault line responsible for the 2008 Sichuan earthquake in China. When earthquakes occur due to tectonic plates rubbing against one another, cracks open up in the ground leaving behind what look like wounds. Researchers have been studying these wounds to see if they might offer any new information that would help scientists better understand earthquakes in general. NASA telescope to probe long-standing solar mystery CAPE CANAVERAL, Florida: A small NASA telescope was recently launched into orbit on a mission to determine how the Sun heats its atmosphere to millions of degrees, sending off rivers of particles that define the boundaries of the solar system. Solar activity directly impacts Earth’s climate and the space environment beyond the planet’s atmosphere. Solar storms can knock out power grids, disrupt radio signals and interfere with communications, navigation and other satellites in orbit. — Agencies |
