The aim of all Question Answering (QA) systems is to be able to generalize to unseen questions. Current supervised methods are reliant on expensive data annotation. Moreover, such annotations can introduce unintended annotator bias which makes systems focus more on the bias than the actual task. In this work, we propose Knowledge Triplet Learning (KTL), a self-supervised task over knowledge graphs. We propose heuristics to create synthetic graphs for commonsense and scientific knowledge. We propose methods of how to use KTL to perform zero-shot QA and our experiments show considerable improvements over large pre-trained transformer models.

This tutorial is on the basics of gradient descent. It is also a continuation of the Intro to Machine Learning post, "What is Machine Learning?", which can be found here. Gradient descent is a method of finding the optimal weights for a model. We use the gradient descent algorithm to find the best machine learning model, with the lowest error and highest accuracy. A common explanation of gradient descent is the idea of standing on an uneven baseball field, blindfolded, and you want to find the lowest point of the field.

Multivariate time series (MTS) forecasting is an important problem in many fields. Accurate forecasting results can effectively help decision-making. Variables in MTS have rich relations among each other and the value of each variable in MTS depends both on its historical values and on other variables. These rich relations can be static and predictable or dynamic and latent. Existing methods do not incorporate these rich relational information into modeling or only model certain relation among MTS variables. To jointly model rich relations among variables and temporal dependencies within the time series, a novel end-to-end deep learning model, termed Multivariate Time Series Forecasting via Heterogenous Graph Neural Networks (MTHetGNN) is proposed in this paper. To characterize rich relations among variables, a relation embedding module is introduced in our model, where each variable is regarded as a graph node and each type of edge represents a specific relationship among variables or one specific dynamic update strategy to model the latent dependency among variables. In addition, convolutional neural network (CNN) filters with different perception scales are used for time series feature extraction, which is used to generate the feature of each node. Finally, heterogenous graph neural networks are adopted to handle the complex structural information generated by temporal embedding module and relation embedding module. Three benchmark datasets from the real world are used to evaluate the proposed MTHetGNN and the comprehensive experiments show that MTHetGNN achieves state-of-the-art results in MTS forecasting task.

From an incisive ethnography of predictive policing to a compelling indictment of technology-enabled learning tools, the books on this year's fall reading list offer valuable context to the myriad challenges currently facing humanity. Dive deep into a public health disaster shrouded in secrecy, sit with the uncomfortable questions raised by a fictional foray into the future of intimacy, confront the challenges to sustainable development posed by environmental racism, and learn what a QR-coded chicken in rural China portends about the future of agriculture. When you are through, sit back and marvel at the odds stacked against humanity from the start with an entertaining romp through evolution and then leave your earthly worries behind with an ambitious tour of the Solar System. —Valerie Thompson Reviewed by Ivor Knight 1 Through a series of chance events, the pathogen we now know as severe acute respiratory syndrome coronavirus 2 emerged in 2019 and infected millions of humans within a span of 6 months. But chance has driven more than just the planet's latest pandemic. In his new book, A Series of Fortunate Events: Chance and the Making of the Planet, Life, and You , Sean B. Carroll takes readers on an entertaining tour of biological discovery that emphasizes the dominant role played by chance in shaping the conditions for life on Earth. Along the way, he provides insights and humor that make the book a quick, lively read that both educates and entertains. Carroll begins with one of the most consequential chance events to have occurred in the history of our planet: the Cretaceous-Paleogene asteroid impact on the Yucatán Peninsula that resulted in the extinction of the dinosaurs and expansion of mammals. Given Earth's rotational speed, if the asteroid had hit 30 minutes earlier or later, scientists believe it would have made a much less consequential impact, landing in either the Atlantic or Pacific Ocean. If that had happened, there might still be dinosaurs today, but no humans. As he does throughout the book, Carroll compares the example from science with an example from popular culture, describing the comedian Seth MacFarlane's good fortune to have narrowly missed (by 30 minutes) one of the flights that was hijacked on 11 September 2001. Fundamental topics such as the roles that mutation and natural selection play in the evolution of diverse life-forms, the genetics of human reproduction, cellular mechanisms of acquired immunity, and the development of cancer are all treated within a framework where chance dominates. Carroll explains in detail how chance creates the genetic diversity upon which natural selection acts and results in the richness of species on Earth, as well as how random combinations among just 163 gene segments make possible a human immune system that can produce up to 10 billion different antibodies. Readers will likely be particularly interested to learn that their genome is only one of the 70 trillion possibilities that could have been produced by their parents. Written in a conversational style, the book reads like an updated version of Jacques Monod's 1970 Chance and Necessity that speaks directly to the reader, making complex subject matter more accessible. There is also a suggested reading list and an extensive bibliography included for further exploration. Carroll's central argument, that we are all here by luck, is certainly clear and compelling. What we choose to do with that luck, however, is where things really get interesting. Books such as this remind us to make our unlikely time here count. Reviewed by Gillian Bowser 2 Does a hurricane discriminate between the wealthy and the poor? Do earthquakes target specific victims? How does systemic racism influence development goals? In academic explorations of sustainable development and environmental responsibilities, our assumptions about the relationship between income and energy consumption remain largely rooted in the idea that social inequalities decrease as countries develop, thus reducing environmental inequality. No such relationship appears to actually exist. In his sobering but essential new book, Unsustainable Inequalities , economist Lucas Chancel explores the intersections of social justice and environmental sustainability with a focus on global goals established at the 2012 United Nations Conference on Sustainable Development, which informed the underlying philosophy of the 2015 Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC) ([ 1 ][1]). Framing his narrative through the lens of intragenerational economic inequalities, he identifies social inequality as a core driver of environmental unsustainability that leads to a vicious circle wherein the rich consume more and the poor lose access to environmental resources and become increasingly vulnerable to environmental shocks. In 1987, the World Commission on Environment and Development issued a report called “Our Common Future” that defined sustainable development as “development that meets the need of the present without compromising the ability of future generations to meet their own needs” ([ 2 ][2]). The idea of intergenerational environmental equity became a cornerstone concept, shifting climate policy toward the common but differentiated responsibilities enshrined in the UNFCCC. Yet questions about intergenerational responsibility and the equitable impacts of climate change and environmental degradation remain. Environmental racism, wherein communities of color are disproportionately exposed to environmental risks, is inseparable from social justice, Chancel argues, and the attainment of sustainable development that also protects the environment across generations is “extremely difficult” without first addressing economic inequality within a single generation. The notion that we may be able to attain sustainable development and achieve equal responsibility for environmental degradation feels more unreachable than ever in a world upended by a global pandemic. In prepandemic times, many nations had already failed to implement or participate in local and global environmental justice efforts, and taxation schemes to level responsibilities for environmental pollution have proven wildly unpopular. And while Chancel argues that common indicator frameworks such as the United Nations' Sustainable Development Goals encourage nations to learn from one another, the continued rise of social inequality is a stark reminder of the difficult road ahead. Reviewed by Kanwal Singh 3 As the pandemic forces so many school systems and learning institutions to move online, the desire to educate students well using online tools and platforms is more pressing than ever. But as Justin Reich illustrates in his new book, Failure to Disrupt , there are no easy solutions or one-size-fits-all tools that can aid in this transition, and many recent technologies that were expected to radically change schooling have instead been used in ways that perpetuate existing systems and their attendant inequalities. The first half of the book discusses the brief histories, limited successes, and challenges of three types of large-scale technology-driven learning environments: instructor-guided, such as lectures taught through massive open online courses (MOOCs); algorithm-guided (e.g., Khan Academy); and peer-guided (e.g., the online coding community known as Scratch). Reich gives a solid accounting of the conditions needed for success with these models, the difficulties and limitations involved in adopting them in K–12 schooling, and the challenges that arise when we attempt to compare different approaches to one another. He argues that although we might think that the availability of a technology is its biggest limiter, the truth is that educational systems are simply not constructed to allow for experimentation and new ways of learning. Reich describes himself as committed to “methodological pluralism.” He supports the use of an array of learning tools and mechanisms, although he confesses to a particular admiration for peer-guided environments. He argues, however, that the incentive structures in formal education do not encourage the more innovative and deeper learning that can blossom in these environments. If we insist on maintaining current methods of assessment and ranking, which center on individual achievement, then peer-guided instruction will remain relegated to the sidelines. The second part of the book expands on the challenges of implementing educational technologies. Reich's main argument here is that educational systems are inherently conservative and that change will happen, albeit slowly and incrementally, only if technology designers, teachers, and administrators work in partnership to understand the desired learning goals and the parameters that define and constrain the learning environments. One of the most intractable pieces of the educational technology puzzle is the need to effectively conduct large-scale assessment, especially when the skills being assessed are not things that computers can do. Here, Reich cites a humorous example of an automated grading system giving high marks to an essay that begins with the technically grammatically correct sentence: “Educatee on an assassination will always be a part of mankind.” At the end of the book, Reich offers four questions that he finds especially useful to consider when examining a new large-scale educational technology. Perhaps the most useful question is the first: “What's new?” Despite what “edtech evangelists” might claim, new technologies often have closely related ancestors that can help predict their success, he argues. In the end, however, new technologies alone are unlikely to have a substantial impact on schooling. We must also be open to changing educational goals and expectations according to the possibilities offered by emergent technologies. Reviewed by Arti Garg 4 In Blockchain Chicken Farm , Xiaowei Wang reveals the myriad ways that technology is transforming our lives. They unveil, for example, the unexpected connections that exist between industrial oyster farming in rural China, livestream-fueled multilevel marketing schemes in the United States, and the app-enabled gig economy in which Chinese influencers participate. Following the threads of places and people woven together by new technologies, Wang helps readers trace the patterns emerging in the tapestry of our tech-infused world. Each chapter provides a view into not just how we use technology but why and to what end. Emphasizing the often-hidden human engine that powers our app-driven economy, Wang exposes the flaw in our tendency to conflate societal and cultural aspirations with the promises of technology and challenges us to honestly measure what value technology delivers. In the 21st century, they argue, we demand that technologists solve the problems that our governments and communities have not. In doing so, we inadvertently empower companies to exploit and amplify those same problems. Most of Wang's vignettes relate to Chinese agriculture. This decision, which roots the narrative in the visceral language of human sustenance, grounds the heady subject matter. The titular example takes readers to the GoGoChicken farm in Sanqiao, a “dreamlike” village that sits in one of the poorest regions in China. Here, Wang introduces the straw-hatted “Farmer Jiang,” who has partnered with his village government and a blockchain company to sell free-range chickens via an e-commerce site. Jiang's chickens sell for RMB 300 (∼$35) each, an amount equal to 6% of the average annual household income in that part of China. Wang explains that high-profile failures of regulatory oversight have left many Chinese with a deep distrust of the food supply chain and that upper-class Chinese urbanites will pay a premium for reassurance about food safety, which, in this case, takes the form of a vacuum-sealed chicken that comes with a QR code revealing blockchain-logged details of its life on the farm. Wang suggests that Americans, driven by concerns over animal welfare, may desire similar reassurance about their food's provenance. In both China and America, they observe, technology allows the upper class to buy its way around governmental and societal shortcomings at prices that are out of reach for most people. Technology does not correct the intrinsic problems, and most cannot reap the benefits of the technological “solutions.” Without resorting to an overly romanticized notion of rural wisdom, Wang treats individuals like Jiang, whose future remains uncertain owing to the vagaries of e-commerce supply chains, with respect and empathy. Because of this, they largely succeed in their goal of reframing our understanding of technology as neither the cause of nor the solution to our problems but rather as a force reshaping the human experience in fundamental ways. Reviewed by Heather Bloemhard 5 The Secret Lives of Planets by Paul Murdin includes a plethora of information about our Solar System. Murdin covers planets, asteroids, moons, dwarf planets, and more, approximately one per chapter. Even exoplanets—the planets that orbit a star other than our Sun—are referenced frequently, although not in their own chapter. Using only a few images, Murdin illustrates the historical and physical concepts that surround each of these elements in prose peppered with anecdotes from his own career as an astronomer. While the book's tone is pleasant and conversational, the discussions are often technical in nature, and I worry that some readers may be frustrated by its many tangents and loose organizational structure. For example, in his discussion of the formation of Mercury, Murdin references the formation of exoplanets, the discovery of 'Oumuamua, and Earth's fossil record. The same chapter also refers to Earth and Venus to help explain orbital eccentricity and precession, but this analogy may fall short for lay readers. I was also disappointed that Murdin relied almost exclusively on the accomplishments of European men to tell the story of how our understanding of the Solar System emerged over time. He writes, for example, of Nicolaus Copernicus's revelations about the geometry of our solar system but neglects the work of Muslim astronomers who developed models of heliocentric orbits hundreds of years earlier. Murdin is far from alone in this misstep, but it is well worth striving to do better. Despite these criticisms, every reader will learn something from this ambitious book. Did you know, for example, that some scientists once believed there were oases of vegetation on Mars, or that others believed that martians might try to colonize Earth? From the exchange of planetary material by way of meteorites to the formation of asteroids, Murdin covers a wide range of astronomical topics, including the aurora of Jupiter, the mysteries of Uranus, and the potential of the moons of Jupiter and Saturn to support recognizable life. I found Murdin's personal recollections to be the most compelling feature of The Secret Lives of Planets . He tells the story of how, as a student, he observed the shadows cast by the tops of clouds of different heights on Venus using a telescope similar to the one used by Galileo and uses this anecdote as a starting point to explain what the Italian astronomer discovered about the planet. Recounting the time he observed the launch of Cassini-Huygens, a probe sent to Saturn's moon Titan, Murdin explains what scientists had hoped to learn from this mission and what they ended up discovering. He also discusses attending the 2006 International Astronomical Union conference, where a debate was held about the definition of a planet, and reveals what it was like to cast a vote on the final decision. In the end, there is much to recommend The Secret Lives of Planets as an introductory text on our solar system. Reviewed by Peter Reczek 6 Modern cancer therapies are often the result of years of targeted research and development, making it easy to forget that many of the field's early breakthroughs had as much to do with chance as they did with preparation. In The Great Secret , Jennet Conant recounts one such breakthrough, which was made in the wake of a deadly disaster. Conant's engrossing story is set in the Italian port town of Bari, which was used as an important staging area for the distribution of supplies supporting Allied troops as they pushed north through Italy during World War II. On 2 December 1943, a day that would later be referred to as “a little Pearl Harbor,” German military aircraft sank more than 20 Allied ships anchored in Bari, leading to the loss of more than 1000 Allied servicemen and Italian civilians. Lieutenant Colonel Stewart Alexander, a medical officer attached to General Eisenhower's headquarters in North Africa, was sent to coordinate medical relief efforts. In Bari, Alexander found “a nightmarish scene.” In the aftermath of the air raid, “The walking wounded staggered in [to the hospital] unaided, suffering from shock, burns, and exposure after having been in the cold water for hours before being rescued. Others had to be supported, as they cradled fractured arms in improvised slings or dragged mangled limbs…Almost all of them were covered in thick, black crude oil,” writes Conant. In addition to the acutely injured, Alexander discovered victims whose injuries had emerged days after the attack and could not be attributed to the percussive effects of the bombing. After analyzing the positions of the ailing seamen, Alexander reported that an American Liberty ship, the John Harvey , was the source of the problem, speculating that it likely contained a secret cache of nitrogen mustard (i.e., mustard gas). Both the American and British governments denied any such cache, but Conant reveals that Alexander persisted, and his controversial report—which, crucially, documented a decrease in white blood cell counts in the victims—was accepted by the Allied High Command with a classification of “Secret.” After the war, Colonel C. P. “Dusty” Rhoads, who had been Alexander's superior during the Bari investigation, reasoned that an agent that reduced white blood cells might be useful in treating some forms of leukemia. While serving as the first director of the Sloan Kettering Institute, Rhoads oversaw a clinical trial to test nitrogen mustards as potential therapeutic agents for the treatment of neoplastic disease. The results exceeded expectations. “In their first attempt to treat patients with inoperable lung cancer with nitrogen mustard, the Memorial team reported that of the thirty-five patients, 74 percent showed some clinical improvement” writes Conant. Many similar compounds, collectively known as alkylating agents, are still the foundation of the combination chemotherapy used to treat some forms of leukemia. Drawing largely from archival research, Conant relies on a loose conversational style to convey a fast-paced medical detective story that demonstrates how careful scientific observation can yield unexpected benefits and serves as a reminder of the difficult choices made by governments to balance public health and secrecy in matters of security. Reviewed by Esha Mathew 7 In quantum physics, entanglement is a property wherein two particles are inextricably linked. Put another way, entangled particles are never truly independent of each other, no matter the distance between them. It is fitting then that Entanglements is an anthology of short stories about inextricably linked people and the impact of emerging technologies on their relationships. A talented set of authors, with deft editing by Sheila Williams, explore the full spectrum of intimacy and technology to great effect. As an added visual treat, illustrations by Tatiana Plakhova punctuate each story with a blend of science, mathematics, and art that complements the subject matter. Even with the length limitations of a short story, the world-building in this compilation is frequently full and often insidiously terrifying, particularly in those stories that use the familiar as breadcrumbs to lure the reader in. The very first tale, “Invisible People” by Nancy Kress, begins with a mundane morning routine and carefully layers in a story about two parents reeling from an unsanctioned genetic experiment on their child. In “Don't Mind Me,” Suzanne Palmer uses the shuffle between high school classes as a foundation on which to build a story about how one generation uses technology to enshrine its biases and inflict them on the next. The ethical implications in these stories offer fodder enough for plenty of late-night discussions. It is also chilling how entirely possible many of the fictional futures seem. But looking forward need not always be bleak. This volume balances darker-themed stories with those in which technology and people collide in uplifting and charming ways. In Mary Robinette Kowal's “A Little Wisdom,” for example, a museum curator, aided by her robotic therapy dog–cum–medical provider, finds the courage within herself to inspire courage in others and save the day. Meanwhile, in Cadwell Turnbull's “Mediation,” a scientist reeling from a terrible loss finally accepts her personal AI's assistance to start the healing process. And in arguably the cheekiest tale in this compilation, “The Monogamy Hormone,” Annalee Newitz tells of a woman who ingests synthetic vole hormones to choose between two lovers, delivering a classic tale of relationship woes with a bioengineered twist. With such a dizzying array of technologies discussed in relation to a range of human emotion and behavior, readers may experience cognitive whiplash as they move from one story to the next. But it is definitely worth the risk. The 10 very different thought experiments presented in this volume make for a fun ride, revealing that human relationships will continue to be as complicated and affirming in the future as they are today. I would recommend the Netflix approach to this highly readable collection: Binge it in one go, preferably with a friend. Reviewed by Joseph B. Keller 8 The U.S. police system is experiencing a reckoning. Protesters across the country (and around the world) have taken to the streets, arguing that police brutality disproportionately harms minority communities, and the current value of policing is being debated by city councils, lawmakers, and members of the news media. Into this tumultuous context enters Sarah Brayne's book, Predict & Surveil: Data, Discretion, and the Future of Policing . A sociologist by training, Brayne synthesizes interview data and field notes from 5 years of observation within the Los Angeles Police Department, employing a firsthand ethnographic approach to reveal how big data are currently used in tech-forward police departments in America. She chronicles both consequential and mundane interactions between officers, civilians, and data. For example, she documents officers uploading license plate numbers, field interview notes, traffic citations, and potential gang affiliations onto a private industry data platform, as well as their active surveillance of hotspots in Los Angeles predicted to be criminogenic. This fly-on-the-wall perspective captures the human aspect of a police force grappling with automated systems and machine-learning decisions in real time, juxtaposing the experiences of individual officers with institutional directives being handed down from administrators and lawmakers. Many police departments contend that the adoption of predictive analytics can improve objectivity and transparency, reduce bias, and increase accountability. Yet Brayne's book reveals how few of these metrics actually improve with predictive policing and exposes the scant evidence that supports the idea that it reduces crime rates. On the contrary, she insists, predictive policing raises glaring civil rights concerns and reinforces harmful racial biases. We all leave digital traces throughout our daily lives, and innocent people can be caught in the dragnet and cataloged in a digital criminal justice system, where a case can be built from benign data. Police unions, Brayne notes, often vehemently oppose the tracking of their own officers. She records incidents of officers turning off their car locator signals, for example, as well as other tactics used to thwart tech-infused managerial oversight. Many officers view policing as an art form rather than a scientific system that can be optimized. To some, big data policing threatens their sense of police instincts and identity. “They worry that they will become nothing more than line workers and insist that their years of accumulated experiential knowledge is irreplaceable,” observes Brayne. Brayne's book raises timely issues relevant to mass surveillance and policing amid a growing debate about facial recognition systems, which makes their omission from this work notable. Although banned in several major American cities, these systems remain a common tool for identifying potential offenders, despite abundant evidence of dangerous inconsistencies. Predictive policing can drive societal inequalities, but Brayne suggests that reducing instances of general police contact may mitigate disparities. In addition to offering immediate recommendations for changing law enforcement in the digital age, she asserts that effective programmatic reforms are typically influenced by external social organizing and guided by communities. (The likelihood of real transformation from within the police system is small, she believes.) For judicial and policing institutions genuinely seeking reform, this book provides powerful observations and analysis that suggest how we can begin. 1. [↵][3]Paris Agreement to the United Nations Framework Convention on Climate Change, 12 December 2015, TIAS No. 16-1104. 2. [↵][4]World Commission on Environment and Development, Our Common Future (Oxford Univ. Press, 1987). [1]: #ref-1 [2]: #ref-2 [3]: #xref-ref-1-1 "View reference 1 in text" [4]: #xref-ref-2-1 "View reference 2 in text"

Flush with money and a hard-won respectability, alien hunters are deploying new telescopes and tactics. In 2015, Sofia Sheikh was at loose ends. Her adviser at the University of California (UC), Berkeley, with whom she studied hot, giant exoplanets, had left for a new job. Browsing reddit, she saw a post about a lavishly funded new search for extraterrestrial intelligence (SETI) and noticed that its leader was also at UC Berkeley: astrophysicist Andrew Siemion. She asked her former adviser for an introduction and met with Siemion when he was still unpacking boxes in a new office. “Everything's kind of history from there,” says Sheikh, who became the team's first undergraduate student. Sheikh is now a Ph.D. student at Pennsylvania State University (Penn State), University Park, where she led a radio survey of 20 nearby star systems aligned with Earth's orbital plane. If an intelligent civilization inhabited one of these systems and pointed a powerful telescope our way, they would see Earth passing in front of the Sun, and they might detect signs of life in our atmosphere. They might even decide to send us a message. The results, published in February in The Astrophysical Journal , were unsurprising. “Spoiler alert: no aliens,” Sheikh jokes. SETI researchers are used to negative results, but they are trying harder than ever to turn that record around. Breakthrough Listen, the $100 million, 10-year, privately funded SETI effort Siemion leads, is lifting a field that has for decades relied on sporadic philanthropic handouts. Prior to Breakthrough Listen, SETI was “creeping along” with a few dozen hours of telescope time a year, Siemion says; now it gets thousands. It's like “sitting in a Formula 1 racing car,” he says. The new funds have also been “a huge catalyst” for training scientists in SETI, says Jason Wright, director of the Penn State Extraterrestrial Intelligence Center, which opened this year. “They really are nurturing a community.” Breakthrough Listen is bolstering radio surveys, which are the mainstay of SETI. But the money is also spurring other searches, in case aliens opt for other kinds of messages—laser flashes, for example—or none at all, revealing themselves only through passive “technosignatures.” And because the data gathered by Breakthrough Listen are posted in a public archive, astronomers are combing through it for nonliving phenomena: mysterious deep-space pulses called fast radio bursts and proposed dark matter particles called axions. “There are untapped possibilities here,” says axion searcher Matthew Lawson of Stockholm University. Perhaps the most important consequence of Breakthrough Listen is that it has nudged SETI, once considered fringe science, toward the mainstream. “Journals are relaxing and letting good technosignature papers be published,” says astrobiologist Jacob Haqq-Misra of the Blue Marble Space Institute of Science. “The giggle factor is reducing.” After nearly 3 decades of eschewing SETI, NASA organized a technosignature workshop in 2018. In June, it awarded a grant to model the detectability of possible technosignatures in the atmospheres of exoplanets, its first ever SETI-related grant not involving radio searches. But some astronomers worry the funding boon is distorting science. Fernando Camilo, chief scientist of the South African Radio Astronomy Observatory, says Breakthrough Listen's voracious appetite for time on large telescopes leaves him uncomfortable. “It leaves less time to do astronomy.” Others say SETI's high-risk, rush-for-the-prize approach could distract funders from a more rational, stepwise search for extraterrestrial life. “We do have a really thoughtful process on what gets funded and what doesn't,” says Harvard University astronomer David Charbonneau. “That doesn't happen with rich individuals.” But SETI proponents don't see themselves as separatists. They are increasingly working hand in hand with those searching for exoplanets and studying astrobiology. “Looking for intelligence is the logical conclusion of this search for life,” says astronomer David Kipping of Columbia University. SETI STARTED SMALL. In 1960, astronomer Frank Drake pointed a 26-meter radio telescope in Green Bank, West Virginia, at two nearby Sun-like stars. He scanned frequencies around 1.42 gigahertz, which correspond to wavelengths of about 21 centimeters—the part of the spectrum where clouds of interstellar hydrogen emit photons. This 21-centimeter glow is ubiquitous, and Drake supposed it might be a universal channel on the cosmic dashboard, a natural place for a clarion “We are here!” But his targets, Tau Ceti and Epsilon Eridani, were expressionless. The survey, called Project Ozma, saw no sign of artifice, such as an intense spike squeezed into a narrow frequency band. With funding from NASA and the National Science Foundation (NSF), however, searches continued, with bigger telescopes to listen for fainter signals and hardware that could scan thousands and eventually millions of narrow frequency channels at once. Drake devised his now famous, eponymous equation that estimates how many communicative extraterrestrial civilizations may exist in the Milky Way. It depends on seven variables, from the rate of star formation to the average lifetime of a civilization. Even though only one of the seven factors—star-formation rate—was known with any certainty, alien hunters were on the prowl. In 1992, NASA decided to look harder, only to quickly reverse course. It embarked on the Microwave Observing Project, a 10-year, $100 million SETI search using several large telescopes. But the following year, the project was ridiculed and cut by lawmakers focused on reducing the federal budget deficit. Ever since, NASA has mostly shied away from SETI. ![Figure][1] CREDITS: (GRAPHIC) N. DESAI/ SCIENCE (DATA) JASON WRIGHT/PENN STATE Even as federal funding shriveled, the 1990s gave SETI an unexpected gift. Until then no one had detected an exoplanet, much less a potentially hospitable one, but that decade brought a host of discoveries. Since then, missions such as NASA's Kepler telescope have suggested that planetless stars are rare, and that about one in five Sun-like stars has potentially habitable Earth-size planets—two more factors in the Drake equation that have fueled optimism among SETI advocates. The turn-of-the-century tech boom offered another boost: newly minted billionaires with a taste for space. A high point came in 2007 with the inauguration of the Allen Telescope Array, a SETI observatory in California kick-started with $11.5 million from Microsoft cofounder Paul Allen. Then the field took another plunge. The 2008 financial crisis struck and within a few years, with federal and state funding tight, UC Berkeley withdrew from the project. The array was put into hibernation for 8 months. A planned expansion from 42 to 350 dishes never materialized. “SETI was entirely decimated,” Siemion says. “I was one of maybe two or three in the whole world working on SETI.” That was when Yuri Milner called. BORN AND EDUCATED in Moscow, Milner worked as a particle physicist at the Lebedev Physical Institute. In 1990, as the Soviet Union collapsed, he left to study business at the University of Pennsylvania, and in 1999 he founded an internet investment fund. The fund was an early backer of Facebook and Twitter, and later Spotify and Airbnb. Forbes magazine puts Milner's net worth at $3.8 billion. “I made some lucky investments,” he tells Science . Milner says he's always felt a connection with space and SETI. He was born in 1961, days after Drake convened the first SETI conference. He is named after Yuri Gagarin, the first cosmonaut. Once he had built up a fortune, “I discovered that now I can give back to science,” he says. He knew of SETI's dire financial straits, and he believed his money and knowledge of the tech industry could help speed up the search. Siemion's UC Berkeley center, across the San Francisco Bay from Milner's home in Silicon Valley, became the beneficiary. Breakthrough Listen set out ambitious goals ( Science , 24 July 2015, p. [357][2]). It would survey 1 million of the closest stars to Earth and 100 nearby galaxies using two of the world's most sensitive steerable telescopes, the 100-meter Green Bank Telescope in West Virginia and the 64-meter Parkes radio telescope in Australia. Buying up about 20% and 25% of the time on those telescopes, Breakthrough Listen promised to cover 10 times more sky than previous surveys and five times more of the radio spectrum, and gather data 100 times faster. Achieving these goals required new hardware. The key electronic component is a digital backend, which chops telescope data into ultrathin frequency slices and records it. Siemion says Breakthrough Listen's backends are “orders of magnitude more powerful than anything else on site.” The instruments are available for 100 hours every year to other astronomers interested in such fine frequency resolution. That allocation is often oversubscribed at Green Bank, Siemion says, ever since the backend helped characterize the first repeating fast radio burst. The project is adding a major new telescope to its mix of collaborations: MeerKAT, a South African array of 64 dishes each 13.5 meters across ( Science , 22 June 2018, p. [1285][3]). Instead of buying time on the array, Breakthrough Listen is tapping into the data stream while the telescope observes its regular targets—a procedure known as commensal observing. “You take what you can get,” Camilo says. “When it works, it's fantastic.” Commensal observing will also be added to the Karl G. Jansky Very Large Array in New Mexico, the workhorse of U.S. radio astronomy, in a project led by the privately funded SETI Institute. Gathering data sets is one thing; scouring heaps of them for alien messages is another. SETI researchers have long looked for energy packed into narrow frequency signals—something that is hard for nature to replicate, although astronomers need to exclude humanmade signals. One test is to see whether the signal's frequency drifts over time: An alien transmitter would be on a moving planet, causing a Doppler shift. If the frequency is rock steady, it's likely to be earthly interference. Similarly, if the signal persists when the telescope moves from its target, it's noise from Earth. But aliens might send something more complex than a single loud note. How do you scan SETI data for something that just seems anomalous or weird? Researchers have been trying to enlist artificial intelligence (AI), but it hasn't been easy. One species of AI, natural language algorithms, can recognize key words in the flow of human speech—think of Amazon's Alexa, or eavesdroppers at the National Security Agency—after being trained on vast speech data sets. But the huge number of narrow frequency channels in SETI data overwhelms these algorithms. Converting the data stream into 2D diagrams that resemble images works better, at least in tests, in which machine vision algorithms picked out strange pictures from a torrent of similar ones. “We have to guess what an anomaly might look like and train the algorithm to look for this, or look for things that look similar,” says Steve Croft of UC Berkeley's SETI Research Center. THE FOCUS OF SETI searches tends to reflect the technology of the times. Radio was in its heyday when Drake started out. But as lasers have grown in power and sophistication, so have efforts to spot alien laser signals with so-called optical SETI. Astronomers have carried out optical searches with modest telescopes since the 1990s. Breakthrough Listen is doing its own, with time on the 2.4-meter Automated Planet Finder (APF) telescope at the Lick Observatory in California. APF has been scanning a sample of stars to distances up to 160 light-years but will now work through a new list: stars with potentially habitable planets identified by NASA's Transiting Exoplanet Survey Satellite ( Science , 30 March 2018, p. [1453][4]). Others are developing telescopes that wouldn't need to target individual stars. The LaserSETI project, funded by the SETI Institute, is a collection of $30,000 mini-observatories, made up of an off-the-shelf fisheye lens, two cameras, and electronics that would gather light from the entire sky. The first was installed last year on an observatory roof north of San Francisco. Eventually, the institute wants to install 60 instruments around the world for 24/7 coverage. LaserSETI's small telescopes would only pick up an especially bright flash from a nearby source. Shelley Wright of UC San Diego hopes to see much farther with the Pulsed All-sky Near-infrared Optical SETI (PANOSETI), an all-sky telescope able to detect ultrashort laser pulses across all optical wavelengths. PANOSETI's design includes lightning-fast photon counters sensitive to pulses less than one-billionth of 1 second long. “It's hard for nature to make that,” Shelley Wright says. It relies on a Fresnel lens, a type used in lighthouses to focus light into a narrow beam. Flipped over, a Fresnel can gather light from a 10°-wide patch of sky onto the photon counters. The team is building two observatories, each an array of 80 telescopes with lenses 50 centimeters across, bunched together in a fly's eye arrangement. The plan is to site the pair 1 kilometer apart—to help root out false positives—at the Palomar Observatory in California. Funded by Qualcomm co-founder Franklin Antonio, the project has built five telescopes but has been stalled by the COVID-19 pandemic. THEN AGAIN, even intelligent aliens might be too busy or too shy to send messages to the stars. So SETI researchers also hope to detect passive signs of technology. People's ideas about what to look for often reflect their time: Consider the 19th century “discovery” of canals on Mars when canals were still a common form of transport on Earth. In 1960, amid rapid economic growth and concerns about energy shortages, physicist Freeman Dyson imagined an advanced society might build a megastructure surrounding a star to capture its energy ( Science , 3 June 1960, p. 1667). Such “Dyson spheres” continue to fascinate and were suggested as an explanation for the strange dimmings of the star KIC 8462852, known as Tabby's Star. In 2015, Jason Wright led a search for the glow of Dyson spheres in 100,000 nearby galaxies, using data from NASA's Wide-field Infrared Survey Explorer satellite. Technosignatures could be more subtle. In the not-too-distant future, ultrasensitive radio telescopes might be able to pick up the beams of a radar, like the ones used for air traffic control, from a distant exoplanet. Future optical telescopes might reveal the glow of a city's lights or its infrared warmth. Heavy industry or geoengineering might leave fingerprints in a planet's atmosphere. These efforts chime with searches for biosignatures, detectable marks that organic life might leave on an exoplanet ( Science , 3 November 2017, p. [578][5]). “The line between technosignatures and biosignatures is blurring,” Sheikh says. “It makes sense to observe both.” In deciding to fund the 2018 workshop on technosignatures, NASA felt that they could be discussed “on a firmer scientific foundation than before,” says Michael New, the agency's deputy associate administrator for research. After the workshop, the wording in NASA funding calls that had for some years excluded SETI-related proposals quietly disappeared. In June, Jason Wright and his colleagues benefited from the new openness when they were awarded a grant to model exoplanet atmospheres and put together a “library” of potential technosignatures, which astronomers can refer to when observing exoplanets. The team will first model chlorofluorocarbons—a pollutant that isn't produced naturally—and vast solar power arrays, because they would leave an obvious cutoff in the ultraviolet part of the spectrum. “What we should look for is things that can't be avoided, civilization's manifestations in the biosphere,” says Adam Frank, lead investigator on the grant at the University of Rochester. BUT EVEN AFTER the fanfare of Breakthrough Listen, SETI remains far from a central concern for most astronomers. In 2018, panels of researchers convened by the National Academies of Sciences, Engineering, and Medicine (NASEM) drew up strategies for NASA on astrobiology and exoplanets. They made scant mention of technosignatures and didn't advise NASA to spend any money on the topic, or, more generally, SETI. SETI enthusiasts say they are trying to avoid being shut out of an even bigger NASEM effort: its decadal survey of astrophysics, a once-a-decade priority setting exercise that is influential with funding agencies and legislators. The survey is due to report early next year. “We've made a big push to get the decadal survey … to explicitly say that NASA and the NSF need to nurture this field,” Jason Wright says. He and colleagues made nine submissions, known as white papers, to the survey, compared with a single white paper in the previous survey. Sheikh says: “There are signs the winds are starting to shift.” But many astronomers think the more important hunt is for alien life of a more basic kind, not the higher risk search for technological societies. “We have to invest in general questions,” says Charbonneau, who co-chaired the NASEM panel that developed the NASA exoplanet hunting strategy. “If we just go for the prize and don't find anything, what have we learned from that?” Mainstream astrobiologists hope the decadal survey will give a thumbs up to the Large UV/Optical/IR Surveyor, or LUVOIR, a proposed NASA space telescope as much as six times wider than the Hubble Space Telescope ( Science , 14 December 2018, p. [1230][6]). It would scrutinize habitable planets for biosignatures and estimate the fraction of them that support life—another term in the Drake equation. “The progress we've made as scientists follows the terms of the Drake equation in order,” says astrobiologist Shawn Domagal-Goldman of NASA Goddard Space Flight Center. “That progress could lead to a search for technosignatures. I could see LUVOIR being used to do that, even though it wasn't designed for such a search.” Jason Wright, however, thinks the potential payoff of SETI is just too tempting to put off the search. In July, he and his colleagues reported the “discovery space”—all the possible locations, frequencies, sensitivities, bandwidths, timings, polarizations, and modulations—that SETI radio surveys have so far explored. The result: If the entire discovery space is represented by the world's oceans, SETI has so far searched the volume of a hot tub. Milner seems ready to support at least a few more SETI hot tubs. He says he wants Breakthrough Listen to continue past 2025, when his initial funding runs out. “It's one of the most existential questions in our universe,” he says. “Just knowing we are not alone … is something that can bring us together here on Earth.” [1]: pending:yes [2]: http://www.sciencemag.org/content/349/6246/357 [3]: http://www.sciencemag.org/content/360/6395/1285 [4]: http://www.sciencemag.org/content/359/6383/1453 [5]: http://www.sciencemag.org/content/358/6363/578 [6]: http://www.sciencemag.org/content/362/6420/1230

We introduce deep switching auto-regressive factorization (DSARF), a deep generative model for spatio-temporal data with the capability to unravel recurring patterns in the data and perform robust short- and long-term predictions. Similar to other factor analysis methods, DSARF approximates high dimensional data by a product between time dependent weights and spatially dependent factors. These weights and factors are in turn represented in terms of lower dimensional latent variables that are inferred using stochastic variational inference. DSARF is different from the state-of-the-art techniques in that it parameterizes the weights in terms of a deep switching vector auto-regressive likelihood governed with a Markovian prior, which is able to capture the non-linear inter-dependencies among weights to characterize multimodal temporal dynamics. This results in a flexible hierarchical deep generative factor analysis model that can be extended to (i) provide a collection of potentially interpretable states abstracted from the process dynamics, and (ii) perform short- and long-term vector time series prediction in a complex multi-relational setting. Our extensive experiments, which include simulated data and real data from a wide range of applications such as climate change, weather forecasting, traffic, infectious disease spread and nonlinear physical systems attest the superior performance of DSARF in terms of long- and short-term prediction error, when compared with the state-of-the-art methods.

Beijing now controls the largest navy in the world and is attempting to double the size of its nuclear warhead stockpile over the next decade; reaction from Fox News senior strategic analyst Gen. Jack Keane, chairman of the Institute for the Study of War. New attack drones, 5th-generation stealth fighter jets, reconfigured cargo planes and Russian-built air defenses are making China's Air Force even deadlier. In fact, all of these advances present a great concern to U.S. war planners. The size of the People's Liberation Army Air Force is reported to include a total of 2,500 aircraft, making it the third-largest in the world, according to the Pentagon's 2020 China Military Power report. U.S. threat assessors are not merely concerned about the size of the Chinese Air Force but the increasing technical sophistication and multi-mission tactics with which it operates.

If you ask pet owners to pick the most difficult part of their workday routine, many would say "mornings." They don't mean the common struggles with getting out of bed or commuting, but rather the emotions involved in leaving their beloved pets behind. The sad look in the pets' eyes suggests this is not an easy time for them either. Surveys conducted by ZenCrate and Zulily show that more than 32 million dogs in the US suffer anxiety when left alone at home, while 84 percent of pet parents frequently worry about their housebound fur babies. There are a number of solutions available, such as pet sitters or daycare facilities, but these do not allow people and pets to actually stay connected.

In recent years, machine learning has been very successful in solving a wide range of problems. In particular, neural networks have reached human, and sometimes super-human, levels of ability in tasks such as language translation, object recognition, game playing, and even driving cars. Prevent out-of-control infrastructure and remove blockers to deployments. With this growth in capability has come a growth in complexity. Data scientists and machine learning engineers must perform feature engineering, design model architectures, and optimize hyperparameters. Since the purpose of the machine learning is to automate a task normally done by humans, naturally the next step is to automate the tasks of data scientists and engineers. This area of research is called automated machine learning, or AutoML. There have been many exciting developments in AutoML recently, and it's important to take a look at the current state of the art and learn about what's happening now and what's coming up in the future. InfoQ reached out to the following subject matter experts in the industry to discuss the current state and future trends in AutoML space. InfoQ: What is AutoML and why is it important? Francesca Lazzeri: AutoML is the process of automating the time consuming, iterative tasks of machine learning model development, including model selection and hyperparameter tuning.

"Our destiny is to become what we think, to have our thoughts become our bodies and our bodies become our thoughts." The next major technological platform for creative expansion of the mind will be cyberspace, or more specifically the Metaverse, a functional successor to today's 2D Internet, with virtual places instead of Webpages. The Internet and smartphones have enabled the rapid and cheap sharing of information, immersive computing will be able to provide the same for experiences. That means that just as we can read, listen to, and watch videos of anything we want today, soon we'll be able to experience stunning lifelike simulations in virtual reality indistinguishable from our physical world. We'll be walking and actively interacting in the Metaverse, not slavishly staring at the flat screens.