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Millimeter wave wireless spectrum deployments will allow vehicular communications to share high data rate vehicular sensor data in real-time. The highly directional nature of wireless links in millimeter spectral bands will require continuous channel measurements to ensure the transmitter (TX) and receiver (RX) beams are aligned to provide the best channel. Using real-world vehicular mmWave measurement data at 28 GHz, we determine the optimal beam sweeping period, i.e. the frequency of the channel measurements, to align the RX beams to the best channel directions for maximizing the vehicle-to-infrastructure (V2I) throughput. We show that in a realistic vehicular traffic environment in Austin, TX, for a vehicle traveling at an average speed of 10.5 mph, a beam sweeping period of 300 ms in future V2I communication standards would maximize the V2I throughput, using a system of four RX phased arrays that scanned the channel 360 degrees in the azimuth and 30 degrees above and below the boresight. We also investigate the impact of the number of active RX chains controlling the steerable phased arrays on V2I throughput. Reducing the number of RX chains controlling the phased arrays helps reduce the cost of the vehicular mmWave hardware while multiple RX chains, although more expensive, provide more robustness to beam direction changes at the vehicle, allowing near maximum throughput over a wide range of beam sweep periods. We show that the overhead of utilizing one RX chain instead of four leads to a 10% drop in mean V2I throughput over six non-line-of-sight runs in real traffic conditions, with each run being 10 to 20 seconds long over a distance of 40 to 90 meters., Comment: IEEE 93rd Vehicular Technology Conference (VTC-Spring)

Farmers in India are finding it more and more difficult to sustain their livelihoods. There are several causes that are responsible for the prevalent agrarian distress in the country, but the predominant reason for this is the substandard prices at which farmers are compelled to sell their produce. Farmers lack the means to transport their produce and sell it to the customers directly. Instead, the produce passes through a long chain of merchants, traders, wholesalers etc. before they reach the customers. This in turn leads to a monumental surge in prices. The only long term, sustainable solution that can benefit both farmers and customers is to empower them to buy and sell directly from each other. But there are 2 major challenges that obstruct direct interaction between farmers and customers. At first, it is not feasible for farmers to cater to individual customers as an individual is likely to buy not more than 10–15 kg at a time while farmers produce in tens of thousands of kilograms. Secondly there is no existing Supply Chain Management or Freight Management solution that can execute deliveries from farm to customers directly. This paper deals with the common challenges faced by the farmer’s and a detailed investigation is carried out to find the possible solutions for the problem. We try to explore a possible solution to aid the dystopian situation of farmers through the system. The system tries to empower and enable farmers to engage in direct interaction and commerce with the consumers by developing a digital platform and integrating all the stakeholders in that platform.

While gazing at the Earth from orbit, some astronauts have described a cognitive shift known as the overview effect. Here we describe an analogous biological overview effect produced by looking at the tiny twig of humanity on the tree of life. We describe the increasingly precise phylogenetic tree of all life on Earth and how it shows us our place in nature among the other eukaryotes, metazoa, vertebrates and apes. We discuss problems with this tree including the assumption of sexual isolation, purely vertical gene transmission and the dependence of the epoch of LUCA (Last Universal Common Ancestor) on the completeness of the tree. We compile and present the most concise taxonomic overview of the evolution of our lineage from LUCA to humans. We conclude with a description of how the biological overview effect might help us survive.

Characterization of the millimeter wave wireless channel is needed to facilitate fully connected vehicular communication in the future. To study the multipath-rich, rapidly varying nature of the vehicular propagation environment, fast millimeter wave channel sounders are required. We present a channel sounder design capable of covering 360 degrees in azimuth and 60 degrees in elevation with 200 individual beam directions in 6.25 ms by using four phased arrays simultaneously. The channel measurements are accompanied by high resolution positioning and video data, allowing channel sounding to be conducted while either the transmitter, or the receiver, or both are moving. Channel sounding campaigns were conducted at multiple urban locations with light traffic conditions in Austin, Texas. Preliminary results show that beam selection at the receiver can lower the effective pathloss exponent to 1.6 for line-of-sight and 2.25 for non line-of-sight., Comment: GLOBECOM 2020 - 2020 IEEE Global Communications Conference, Taipei, Taiwan, Dec. 2020

Summary: As part of the NASA Frontier Development Lab, we implemented a parallelized cloud-based exploration strategy to better understand the statistical distributions and properties of potential planetary atmospheres. Starting with a modern-day Earth atmosphere, we iteratively and incrementally simulated a range of atmospheres to infer the landscape of the multi-parameter space, such as the abundances of biological mediated gases that would yield stable (non-runaway) planetary atmospheres on Earth-like planets around solar-type stars. Our current dataset comprises of 124,314 simulated models of earth-like exoplanet atmospheres and is available publicly on the NASA Exoplanet Archive. Our scalable approach of analysing atmospheres could also help interpret future observations of planetary atmospheres by providing estimates of atmospheric gas fluxes and temperatures as a function of altitude, and thereby enable high-throughput first-order assessment of the potential habitability of exoplanetary surfaces. Introduction: The NASA Frontier Development Laboratory (FDL) is an annual science accelerator that focuses on applying machine learning and large-scale computing to challenges in space science and exploration (Cabrol et al. 2018). FDL engages interdisciplinary teams of computer scientists and space science domain experts and tasks them to solve problems that are valuable to NASA and humanity’s future. We implemented a cloud-based strategy to better understand the statistical distributions of habitable planets and life in the universe and layout an avenue to characterize the potential role of biological regulation of planetary atmospheres. We simulated a range of atmospheres to infer the landscape of the multi-parameter space, such as the abundances of biological mediated gases that would yield stable (non-runaway) planetary atmospheres on Earth-like planets around solar-type stars. Our scalable tool, once coupled to a generalized ecosystem model, could help derive estimates of the biological mediated atmospheric gas fluxes and help constrain the type and the extent of exobiology on exoplanets based on the remotely detected atmospheric compositions. Method: Our team generated data for a wide variety of hypothetical biospheres to scope out the plausible range of habitable atmospheres and metabolisms that could be present in the universe. We implemented a cloud-based massively parallelized procedural parameter search for a wide range of planetary atmospheres. Since existing tools were not capable of broad parameter scans, we streamlined the ATMOS 1-D atmospheric simulation code developed by the NASA Virtual Planetary Laboratory (Arney et al. 2016, Meadows et al. 2016). and produced a package for the community called PyAtmos (https://github.com/PyAtmos). This package dramatically increases the usability and accessibility of the ATMOS 1-D software across a range of platforms. We then used PyAtmos on the Google Cloud Platform in an automated and scalable procedure to search the parameter space of atmospheric compositions. Our search considered the relative concentrations of greenhouse gases such as methane, carbon dioxide and water. 124,314 different atmospheres were simulated and then analyzed to establish if the planetary surface temperatures and fluxes of gases were compatible with conditions that could maintain a liquid water inventory on the planetary surface. Results: The dataset of planetary atmospheres we have generated can be used for training machine learning models to bootstrap the ATMOS code. It is an open-source dataset (https://exoplanetarchive.ipac.caltech.edu/cgi-bin/FDL/nph-fdl?atmos) available for the community to understand distributions of habitability parameters such as surface temperatures and free energy available to life on different classes of atmosphere bearing planets. All of these are based around an Earth-like planet that orbits a star similar to the Sun, but with different gas mixtures in their atmospheres. A parameter space of possible atmospheres was scanned by varying the concentrations of six gases - Carbon dioxide, Oxygen, Water, Methane, Hydrogen and Nitrogen. In future work, we plan to include parameters such as star type, planet size and distance from the host star when evaluating the range of different atmospheres that may be habitable. The scalability of our framework provides a mechanism to incorporate complex biogeochemical and global climate models to better understand the co-evolution of the atmosphere and biosphere (e.g. Chopra et al. 2016, Gebauer et al. 2017, Nicholson et al. 2018, Lineweaver et al. 2018). Analyses of such multi-dimensional datasets will enable better interpretations of future observations of exo-atmospheres and biosignatures by upcoming telescopes (Fuji et al. 2018). References Arney, G. N. et al. (2016) The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth. Astrobiology, 16(11), 873–899. Cabrol, N. A., et al. (2018) Advancing Astrobiology Through Public/Private Partnership: The FDL Model. In: Lunar and Planetary Science Conference. Vol. 49. Lunar and Planetary Science Conference, 1275. Chopra, A. and Lineweaver, C. H. (2016) The Case for a Gaian Bottleneck: The Biology of Habitability. Astrobiology, 16(1), 7–22. Fujii, Y. et al. (2018) Exoplanet Biosignatures: Observational Prospects. Astrobiology, 18(6). Gebauer, S. et al. (2017) Evolution of Earth-like Extrasolar Planetary Atmospheres: Assessing the Atmospheres and Biospheres of Early Earth Analog Planets with a Coupled Atmosphere Biogeochemical Model. Astrobiology, 17(1), 27–54. Lineweaver, C. H. et al. (2018), The Evolution of Habitability: Characteristics of Habitable Planets, in Vera M. Kolb (Ed.) Handbook of Astrobiology, Taylor & Francis Meadows, V. S. et al. (2016) The Habitability of Proxima Centauri b: Environmental States and Observational Discriminants. Astrobiology, 18(2), 133– 189. Nicholson, A. E. et al. (2018). Gaian bottlenecks and planetary habitability maintained by evolving model biospheres: The ExoGaia model. Monthly Notices of the Royal Astronomical Society, 477(1), 727–740.

Ice-giant-sized planets are the most common type of observed exoplanet, yet the two ice giants in our own solar system (Uranus and Neptune) are the least explored class of planet, having only been observed through ground-based observations and a single flyby each by Voyager 2 approximately 30 years ago. These single flybys were unable to characterize the spatial and temporal variability in ice giant magnetospheres, some of the most odd and intriguing magnetospheres in the solar system. They also offered only limited constraints on the internal structure of ice giants; understanding the internal structure of a planet is important for understanding its formation and evolution. The most recent planetary science Decadal Survey by the U.S. National Academy of Sciences, “Vision and Voyages for Planetary Science in the Decade 2013–2022,” identified the ice giant Uranus as the third highest priority for a Flagship mission in the decade 2013–2022. However, in the event that NASA or another space agency is unable to fly a Flagship-class mission to an ice giant in the next decade, this paper presents a mission concept for a focused, lower cost Uranus orbiter called OCEANUS (Origins and Composition of the Exoplanet Analog Uranus System). OCEANUS would increase our understanding of the interior structure of Uranus, its magnetosphere, and how its magnetic field is generated. These goals could be achieved with just a magnetometer and the spacecraft's radio system. This study shows that several of the objectives outlined by the Decadal Survey, including one of the two identified as highest priority, are within reach for a New-Frontiers-class mission.

The use of 1-bit DACs for downlink massive MIMO system can significantly reduce base station energy consumption and hardware complexity with the tradeoff being the introduction of nonlinear impairments in the transmitted signal. We analyze the corresponding received signal at the single antenna users through Bussgang decomposition and spectral analysis up to third order harmonics. Through mathematical investigation and simulations, we also evaluate the spectral emissions, signal to quantization and interference ratio (SQINR), along with the achievable rate at the receivers. We observe that SQINR and achievable rate per user achieve a maximum for a nontrivial optimum number of users, which we estimate through our analyses.

Astrobiology is the science that seeks to understand the story of life in our universe. Astrobiology includes investigation of the conditions that are necessary forlife to emerge and flourish, the origin of life, the ways that life has evolved and adaptedto the wide range of environmental conditions here on Earth, the search for life beyondEarth, the habitability of extraterrestrial environments, and consideration of the future oflife both here on Earth and elsewhere. It therefore requires knowledge of physics,chemistry and biology, and many more specialized scientific areas including astronomy,geology, planetary science, microbiology, atmospheric science and oceanography. Fil: Domagal Goldman, Shawn D.. National Aeronautics And Space Administration; Estados Unidos Fil: Wright, Katherine. University Of Bristol; Reino Unido Fil: Adamala, Katarzyna. University Of Minnesota; Estados Unidos Fil: Antonio, Marina. Washington State University. School Of Earth & Environmental Sciences; Estados Unidos Fil: Arino de la Rubia, Leigh. University Of New South Wales; Australia Fil: Carter Bond, Jade. University Of New South Wales; Australia Fil: Dartnell, Lewis. University Of Leicester; Reino Unido Fil: Goldman, Aaron. Oberlin College; Reino Unido Fil: Paulino Lima, Ivan Glaucio. National Aeronautics And Space Administration; Estados Unidos Fil: Lynch, Kennda. Colorado School; Estados Unidos Fil: Naud, Marie Eve. Université Du Québec A Montreal; Canadá Fil: Singer, Kelsi. Southwest Research Institute; Estados Unidos Fil: Abrevaya, Ximena Celeste. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Anderson, Rika. University of Washington; Estados Unidos Fil: Arney, Giada. University of Washington; Estados Unidos Fil: Atri, Dimitra. International Centre Of Theoretical Science. Tata Institute Of Fundamental Research; España Fil: Azua Bustos, Armando. Pontificia Universidad Católica de Chile; Chile Fil: Bowman, Jeff. Lamont Doherty Earth Observatory; Estados Unidos Fil: Brazelton, William. University of Utah; Estados Unidos Fil: Brennecka, Gregory. Westfalische Wilhelms Universitat; Alemania Fil: Carns, Regina. University of Washington; Estados Unidos Fil: Chopra, Adytia. Australian National University; Australia Fil: Collangelo Lillis, Jess. McGill University; Estados Unidos Fil: Crockett, Christopher. University Of Carnegie Mellon; Estados Unidos Fil: DeMarines, Julia. University Of Carnegie Mellon; Estados Unidos Fil: Frank, Elizabeth. University Of Carnegie Mellon; Estados Unidos Fil: Frantz, Carie. University of Washington; Estados Unidos Fil: Galante, Douglas. Brazilian Synchrotron Light Laboratory; Brasil Fil: Glass, Jennifer. Georgia Institute Of Techology; Estados Unidos Fil: Gleeson, Damhait. Instituto Nacional de Tecnica Aeroespacial; España

We present FireSim, an open-source simulation platform that enables cycle-exact microarchitectural simulation of large scale-out clusters by combining FPGA-accelerated simulation of silicon-proven RTL designs with a scalable, distributed network simulation. Unlike prior FPGA-accelerated simulation tools, FireSim runs on Amazon EC2 F1, a public cloud FPGA platform, which greatly improves usability, provides elasticity, and lowers the cost of large-scale FPGA-based experiments. We describe the design and implementation of FireSim and show how it can provide sufficient performance to run modern applications at scale, to enable true hardware-software co-design. As an example, we demonstrate automatically generating and deploying a target cluster of 1,024 3.2 GHz quad-core server nodes, each with 16 GB of DRAM, interconnected by a 200 Gbit/s network with 2 microsecond latency, which simulates at a 3.4 MHz processor clock rate (less than 1,000x slowdown over real-time). In aggregate, this FireSim instantiation simulates 4,096 cores and 16 TB of memory, runs ∼14 billion instructions per second, and harnesses 12.8 million dollars worth of FPGAs---at a total cost of only ∼$100 per simulation hour to the user. We present several examples to show how FireSim can be used to explore various research directions in warehouse-scale machine design, including modeling networks with high-bandwidth and low-latency, integrating arbitrary RTL designs for a variety of commodity and specialized datacenter nodes, and modeling a variety of datacenter organizations, as well as reusing the scale-out FireSim infrastructure to enable fast, massively parallel cycle-exact single-node microarchitectural experimentation.

The breakup of the supercontinent Pangaea over the past ~ 180 million years has left its imprint on the global distribution of species and resulted in vicariance-driven allopatric speciation. Here we test the idea that the molecular clock dates for the divergences of species whose geographic ranges were divided, should agree with the palaeomagnetic dates for the continental separations. Our analysis of recently available phylogenetic divergence dates of 42 pairs of vertebrate taxa, selected for their reduced ability to have undergone dispersal-driven speciation, demonstrates that the divergence dates in phylogenetic trees of continent-bound terrestrial and freshwater vertebrates are consistent with the palaeomagnetic dates of continental separation.

In this paper, a system is proposed for real-time calculation of digital predistortion (DPD) coefficients to linearize wideband radio frequency (RF) power amplifiers (PAs). The proposed system leverages the commercially available National Instruments (NI) PXIe-5646R vector signal transceiver (VST) platform. The VST is a single module RF instrument that combines a 200MHz instantaneous vector signal analyzer (VSA) and vector signal generator (VSG) with a shared Xilinx LX240T field-programmable gate array (FPGA). The FPGA is used to perform look-up table (LUT) predistorter estimation and predistortion in real-time. The proposed system is shown to reduce the time to generate a predistorted waveform by over two orders of magnitude compared to a software implementation. Furthermore, the linearity achieved with the proposed FPGA implementation closely matches a traditional software-based approach, with 15dB improvement in adjacent channel leakage ratio (ACLR) and a 3x improvement in error vector magnitude (EVM) for a 3G mobile handset power amplifier.

The prerequisites and ingredients for life seem to be abundantly available in the Universe. However, the Universe does not seem to be teeming with life. The most common explanation for this is a low probability for the emergence of life (an emergence bottleneck), notionally due to the intricacies of the molecular recipe. Here, we present an alternative Gaian bottleneck explanation: If life emerges on a planet, it only rarely evolves quickly enough to regulate greenhouse gases and albedo, thereby maintaining surface temperatures compatible with liquid water and habitability. Such a Gaian bottleneck suggests that (i) extinction is the cosmic default for most life that has ever emerged on the surfaces of wet rocky planets in the Universe and (ii) rocky planets need to be inhabited to remain habitable. In the Gaian bottleneck model, the maintenance of planetary habitability is a property more associated with an unusually rapid evolution of biological regulation of surface volatiles than with the luminosity and distance to the host star.

For life-forms like us, the most important feature of Earth is its habitability. Understanding habitability and using that knowledge to locate the nearest habitable planet may be crucial for our survival as a species. During the past decade, expectations that the universe could be filled with habitable planets have been bolstered by the increasingly large overlap between terrestrial environments known to harbor life and the variety of environments on newly detected rocky exoplanets. The inhabited and uninhabited regions on Earth tell us that temperature and the presence of water are the main constraints that can be used in a habitability classification scheme for rocky planets. Our compilation and review of recent exoplanet detections suggests that the fraction of stars with planets is ∼100%, and that the fraction with rocky planets may be comparably large. We review extensions to the circumstellar habitable zone (HZ), including an abiogenesis habitable zone and the galactic habitable zone.

In this article, a novel method of performing subband analysis of digital signals is proposed. Conventional subband decomposition algorithms typically use a binary tree filterbank structure comprised of halfband filters. Due to design limitations of finite length filters, conventional decomposition algorithms typically suffer from interference due to aliasing. While longer halfband filters may reduce aliasing, such filters also increase latency and implementation complexity. Our proposed algorithm uses a novel structure of quadrature mirror filters to ensure aliasing is present outside of the spectral region of interest. Simulation results indicate that, compared to conventional algorithms, the proposed algorithm 1) reduces interference from aliasing by over 30dB, 2) reduces signal processing latency, and 3) reduces implementation complexity.

An hypothesis is tested that individual peptides corresponding to the transmembrane helices of the membrane protein, rhodopsin, would form helices in solution similar to those in the native protein. Peptides containing the sequences of helices 1, 4 and 5 of rhodopsin were synthesized. Two peptides, with overlapping sequences at their termini, were synthesized to cover each of the helices. The peptides from helix 1 and helix 4 were helical throughout most of their length. The N- and C-termini of all the peptides were disordered and proline caused opening of the helical structure in both helix 1 and helix 4. The peptides from helix 5 were helical in the middle segment of each peptide, with larger disordered regions in the N- and C-termini than for helices 1 and 4. These observations show that there is a strong helical propensity in the amino acid sequences corresponding to the transmembrane domain of this G-protein coupled receptor. In the case of the peptides from helix 4, it was possible to superimpose the structures of the overlapping sequences to produce a construct covering the whole of the sequence of helix 4 of rhodopsin. As similar superposition for the peptides from helix 1 also produced a construct, but somewhat less successfully because of the disordering in the region of sequence overlap. This latter problem was more severe for helix 5 and therefore a single peptide was synthesized for the entire sequence of this helix, and its structure determined. It proved to be helical throughout. Comparison of all these structures with the recent crystal structure of rhodopsin revealed that the peptide structures mimicked the structures seen in the whole protein. Thus similar studies of peptides may provide useful information on the secondary structure of other transmembrane proteins built around helical bundles.

The intradiskal surface of the transmembrane protein, rhodopsin, consists of the amino terminal domain and three loops connecting six of the seven transmembrane helices. This surface corresponds to the extracellular surface of other G-protein receptors. Peptides that represent each of the extramembraneous domains on this surface (three loops and the amino terminus) were synthesized. These peptides also included residues which, based on a hydrophobic plot, could be expected to be part of the transmembrane helix. The structure of each of these peptides in solution was then determined using two-dimensional 1H nuclear magnetic resonance. All peptide domains showed ordered structures in solution. The structures of each of the peptides from intradiskal loops of rhodopsin exhibited a turn in the central region of the peptide. The ends of the peptides show an unwinding of the transmembrane helices to form this turn. The amino terminal domain peptide exhibited alpha-helical regions with breaks and bends at proline residues. This region forms a compact domain. Together, the structures for the loop and amino terminus domains indicate that the intradiskal surface of rhodopsin is ordered. These data further suggest a structural motif for short loops in transmembrane proteins. The ordered structures of these loops, in the absence of the transmembrane helices, indicate that the primary sequences of these loops are sufficient to code for the turn.

We review the most fundamental features common to all terrestrial life. We argue that the ubiquity of these features makes them the best candidates for being features of extraterrestrial life. Other frequently espoused candidates are less secure because they are based on subjective notions of universal fitness, not on features common to all terrestrial life. For example, major transitions in the evolutionary pathway that led to Homo sapiens are sometimes considered to be fundamental transitions in the evolution of all life. However, these “major transitions” are largely arbitrary because a series of different major transitions can be identified along the evolutionary pathway to any extant species.

Channel shortening equalizers are used in acoustics to reduce reverberation, in error control decoding to reduce complexity, and in communication receivers to reduce inter-symbol interference. The cascade of a channel and channel shortening equalizer ideally produces an overall impulse response that has most of its energy compacted into fewer adjacent samples. Once designed, channel shortening equalizers filter the received signal on a per-sample basis and need to be adapted or re-designed if the channel impulse response changes significantly. In this paper, we evaluate sparse filters as channel shortening equalizers. Unlike conventional dense filters, sparse filters have a small number of non-contiguous non-zero coefficients. Our contributions include (1) proposing optimal and sub-optimal low complexity algorithms for sparse shortening filter design, and (2) evaluating impulse response energy compaction vs. design and implementation stage computational complexity tradeoffs for the proposed algorithms. We apply the proposed equalizer design procedures to (1) asymmetric digital subscriber line channels and (2) underwater acoustic communication channels. Our simulation results utilize measured channel impulse responses and show that sparse filters are able to achieve the same channel energy compaction with half as many coefficients as dense filters.