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Robots Tackle DARPA Underground Challenge

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Engineering 2022年第6期8卷 2-4页

作者： Mitch leslie Senior Technology Writer

In a narrow passageway beneath the city of Louisville, KY, USA, a meter-tall robot with a yellow, rectangular body and four limbs that resemble a dog’s legs carefully descended a rocky slope. But as the robot attempted to turn, it lost its footing and tumbled down the slope, landing on its side. A modified commercial model known as‘‘Spot,”the machine almost immediately began extending and rotating its legs, pushing against the floor of the passageway. In about 40 s, it stood upright again and resumed exploring the passage.

关键词： robot beneath DARPA

Internet Satellite Boom Presents Astronomical Problems

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Engineering 2020年第8期6卷 849-850页

作者： Mitch leslie Senior Technology Writer

The SpaceX rocket that lifted off from the Kennedy Space Center in Florida on 22 April carried a payload that worries many astronomers[1].The 60 satellites that the rocket transported into space added to a population explosion of objects in low-Earth *** number of orbiting satellites visible to the unaided eye has already doubled in just over a year,according to calculations by astrophysicist Jonathan McDowell of the Harvard–Smithsonian Center for Astrophysics in Cambridge,MA,*** the number of objects in low-Earth orbit could grow more than 10-fold this decade if SpaceX and other companies follow through on their plans to launch "mega-constellations"of hundreds or thousands of satellites[2].

关键词： payload companies hundreds

Space Tourism Begins to Take Off

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Engineering 2022年第3期8卷 4-6页

作者： Mitch leslie 机构不详

A record number of non-astronauts flew into space in 2021,including a 90-year-old actor,a physician’s assistant,a football player turned TV host,a Dutch teenager,and four *** companies that sent most of these civilians aloft-Virgin Galactic,Blue Origin,and SpaceX-hope the flights will inaugurate a boom in space *** Origin,started by Amazon founder Jeff Bezos,claims it has sold nearly 100 million USD of tickets for upcoming trips[1],while 700 people have paid up to 450000USD apiece for places on future flights by Virgin Galactic,launched by British billionaire Richard Branson[2].

关键词： companies Amazon Virgin

Will Cryptocurrencies Break the Energy Bank?

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Engineering 2020年第5期6卷 489-490页

作者： Mitch leslie Senior Technology Writer

Bitcoin is just over a decade old,and estimates suggest it already consumes more energy than many countries[1].The electricity use and potential environmental impact of Bitcoin and similar cryptocurrency systems alarm some experts and in 2019 prompted China to propose a ban on cryptocurrency mining—although the Chinese government later decided not to follow through[2].However,a well-publicized paper recently posted(August 2019)on the pre-print server arXiv describes a novel algorithm for securing digital transactions that would require little energy[3,4].It is just one of hundreds of proposals for cutting cryptocurrencies’electricity demand.

关键词： prompt server hundreds

Texas Crisis Highlights Grid Vulnerabilities

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Engineering 2021年第10期7卷 1348-1350页

作者： Mitch leslie 机构不详

In February 2021,during a massive blackout in Texas,USA,a man made the news for using his hybrid Ford F-150 pickup truck,a model equipped with a generator,to power his house for three days[1].Other hybrid F-150 owners followed suit,and Ford requested that its Texas dealerships lend out the trucks on their lots so that more people could access these mini-power stations during the week-long disaster[2].That some residents had to rely on their pickup trucks to provide electricity for their homes illustrates the severity of the grid crisis that paralyzed *** an average of 42 h,69%of Texans had no electricity(Fig.1)[3],leaving many homes without heat as temperatures fell to record *** half of the population also lacked running water because water plants lost power[3].According to the state’s figures,hypothermia,carbon monoxide poisoning,and other storm-related causes exacerbated by the power outage killed at least 210 people[4],but one analysis put the death toll at 700[5].The economic price tag,including damage to homes and businesses from burst pipes,may be as high as 200 billion USD[6].

关键词： Texas disaster equipped

Robotic Boats Test the Water

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Engineering 2022年第5期8卷 6-8页

作者： Mitch leslie Senior Technology Writer

An open-topped, metallic gray boat about the size of a compact car churns across a small harbor in central Amsterdam, the Netherlands. The craft detours around a pier jutting into the harbor and then slows as it approaches a customized dock. Turning sideways, it eases closer and closer until two hooks swing out from its side and latch onto the dock.

关键词： hook closer harbor

The Role of Dopamine in Associative Learning in Drosophila: An Updated Unified Model

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Neuroscience Bulletin 2021年第6期37卷 831-852页

作者： Mohamed Adel leslie C.Griffith Department of Biology Volen National Center for Complex Systems and National Center for Behavioral GenomicsBrandeis UniversityWalthamMA 02454-9110USA

Learning to associate a positive or negative experience with an unrelated cue after the presentation of a reward or a punishment defines associative *** ability to form associative memories has been reported in animal species as complex as humans and as simple as insects and sea *** memory has even been reported in tardigrades[1],species that diverged from other animal phyla 500 million years *** the mechanisms of memory formation is a fundamental goal of neuroscience *** this article,we work on resolving the current contradictions between different Drosophila associative memory circuit models and propose an updated version of the circuit model that predicts known memory behaviors that current models do ***,we propose a model for how dopamine may function as a reward prediction error signal in Drosophila,a dopamine function that is well-established in mammals but not in insects[2,3].

关键词： associative contradiction function

Records Broken for Optical Fiber Capacity and Distance

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Engineering 2021年第2期7卷 139-140页

作者： Mitch leslie 机构不详

In August of 2020,engineers at University College London(UCL)in the United Kingdom reported a new record for transmitting data through a single optical fiber,hitting 178 terabits per second(Tbps)and beating the old mark by 20%[1].And in June 2020,two US telecommunications companies,Sunnyvale,CA-based Infinera and Little Rock,AK-based Windstream,reached another *** the first time,the collaborators maintained an 800 gigabits per second(Gbps)transmission rate in one fiber over a long distance,using a line running more than 730km from San Diego,CA,to Phoenix,AZ,USA[2].

关键词： fiber companies maintained

Approximating the Gaussian as a Sum of Exponentials and its Applications to the Fast Gauss Transform

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Communications in Computational Physics 2022年第1期31卷 1-26页

作者： Shidong Jiang leslie Greengard Department of Mathematical Sciences New Jersey Institute of TechnologyNewarkNJ 07102USA Courant Institute of Mathematical Sciences New York UniversityNew YorkNY 10012USA Center for Computational Mathematics Flatiron InstituteSimons FoundationNew YorkNY 10010USA

We develop efficient and accurate sum-of-exponential(SOE)approximations for the Gaussian using rational approximation of the exponential function on the negative real *** digit accuracy can be obtained with eight terms and ten digit accuracy can be obtained with twelve *** representation is of potential interest in approximation theory but we focus here on its use in accelerating the fast Gauss transform(FGT)in one and two *** one-dimensional scheme is particularly straightforward and easy to implement,requiring only twenty-four lines of MATLAB *** two-dimensional version requires some care with data structures,but is significantly more efficient than existing *** a detailed presentation of the theoretical foundations,we demonstrate the performance of the fast transforms with several numerical experiments.

关键词： Fast Gauss transform sum-of-exponential approximation best rational approximation model reduction