Accurate and Interactive Visual-Inertial Sensor Calibration with Next-Best-View and Next-Best-Trajectory Suggestion

Visual-Inertial (VI) sensors are popular in robotics, self-driving vehicles, and augmented and virtual reality applications. In order to use them for any computer vision or state-estimation task, a good calibration is essential. However, collecting informative calibration data in order to render the calibration parameters observable is not trivial for a non-expert. In this work, we introduce a novel VI calibration pipeline that guides a non-expert with the use of a graphical user interface and information theory in collecting informative calibration data with Next-Best-View and Next-Best-Trajectory suggestions to calibrate the intrinsics, extrinsics, and temporal misalignment of a VI sensor. We show through experiments that our method is faster, more accurate, and more consistent than state-of-the-art alternatives. Specifically, we show how calibrations with our proposed method achieve higher accuracy estimation results when used by state-of-the-art VI Odometry as well as VI-SLAM approaches. The source code of our software can be found on: https://github.com/chutsu/yac.Comment: 8 pages, 11 figures, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2023

How to protect half of Earth to ensure it protects sufficient biodiversity

It is theoretically possible to protect large fractions of species in relatively small regions. For plants, 85% of species occur entirely within just over a third of the Earth’s land surface, carefully optimized to maximize the species captured. Well-known vertebrate taxa show similar patterns. Protecting half of Earth might not be necessary, but would it be sufficient given the current trends of protection? The predilection of national governments is to protect areas that are “wild,” that is, typically remote, cold, or arid. Unfortunately, those areas often hold relatively few species. Wild places likely afford the easier opportunities for the future expansion of protected areas, with the expansion into human-dominated landscapes the greater challenge. We identify regions that are not currently protected, but that are wild, and consider which of them hold substantial numbers of especially small-ranged vertebrate species. We assess how successful the strategy of protecting the wilder half of Earth might be in conserving biodiversity. It is far from sufficient. (Protecting large wild places for reasons other than biodiversity protection, such as carbon sequestration and other ecosystem services, might still have importance.) Unexpectedly, we also show that, despite the bias in establishing large protected areas in wild places to date, numerous small protected areas are in biodiverse places. They at least partially protect significant fractions of especially small-ranged species. So, while a preoccupation with protecting large areas for the sake of getting half of Earth might achieve little for biodiversity, there is more progress in protecting high-biodiversity areas than currently appreciated. Continuing to prioritize the right parts of Earth, not just the total area protected, is what matters for biodiversity

Achievable Precision of Close Modes in Operational Modal Analysis: Wide Band Theory

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.This work takes up the challenge of deriving the ‘uncertainty law’ for close modes, i.e., closed form analytical expressions for the remaining uncertainty of modal parameters identified using (output-only) ambient vibration data. In principle the uncertainty law can be obtained from the inverse of the Fisher Information matrix of modal parameters. The key mathematical challenges stem from analytical treatment of entangled stochastic dynamics with a large number of modal parameters of different nature and the quest for closed form expressions for identification uncertainty, whose possibility is questionable. Fortunately the problem still admits insightful closed form solution under long data, high signal-to-noise ratio and wide resonance band for identification. Up to modelling assumptions and the use of probability, the uncertainty law dictates the achievable precision of modal properties regardless of the identification algorithm used. A companion paper discusses the insights, verification, scientific implications and recommendation for ambient test planning.Engineering and Physical Sciences Research Council (EPSRC

Electrodeposition of pyrrole and 3-(4-tert-butylphenyl)thiophene copolymer for supercapacitor applications

The electropolymerization of pyrrole (Py), 3-(4-tert-butylphenyl)thiophene (TPT) monomer or the mixed Py and TPT monomers on stainless steel mesh substrate were performed in 1 M LiClO4/acetonitrile solution. A much lower potential of 0.75 V was required for the co-electropolymerization of Py and TPT, in sharp contrast to that of 1.20 V for poly(3-(4-tert-butylphenyl)thiophene) (PTPT) formation. The resultant homopolymers and copolymer were characterized with FESEM and FTIR, and assembled into supercapacitors to investigate their electrochemical performances. The copolymer electrode delivered the highest specific capacitance of 291 F g−1 at a scan rate of 5 mV s−1, in comparison with that of 216 and 26 F g−1 for PPy and PTPT, respectively. This copolymer also exhibited a greatly improved cycling stability – only 9% of capacitance decrease was observed after 1000 charging–discharging cycles at a current density of 5 A g−1, while the capacitance losses for PPy and PTPT were 16% and 60%, respectively

An Shp2/SFK/Ras/Erk Signaling Pathway Controls Trophoblast Stem Cell Survival

SummaryLittle is known about how growth factors control tissue stem cell survival and proliferation. We analyzed mice with a null mutation of Shp2 (Ptpn11), a key component of receptor tyrosine kinase signaling. Null embryos die peri-implantation, much earlier than mice that express an Shp2 truncation. Shp2 null blastocysts initially develop normally, but they subsequently exhibit inner cell mass death, diminished numbers of trophoblast giant cells, and failure to yield trophoblast stem (TS) cell lines. Molecular markers reveal that the trophoblast lineage, which requires fibroblast growth factor-4 (FGF4), is specified but fails to expand normally. Moreover, deletion of Shp2 in TS cells causes rapid apoptosis. We show that Shp2 is required for FGF4-evoked activation of the Src/Ras/Erk pathway that culminates in phosphorylation and destabilization of the proapoptotic protein Bim. Bim depletion substantially blocks apoptosis and significantly restores Shp2 null TS cell proliferation, thereby establishing a key mechanism by which FGF4 controls stem cell survival

Regulation of denitrification at the cellular level: a clue to the understanding of N2O emissions from soils

Denitrifying prokaryotes use NOx as terminal electron acceptors in response to oxygen depletion. The process emits a mixture of NO, N2O and N2, depending on the relative activity of the enzymes catalysing the stepwise reduction of NO3− to N2O and finally to N2. Cultured denitrifying prokaryotes show characteristic transient accumulation of NO2−, NO and N2O during transition from oxic to anoxic respiration, when tested under standardized conditions, but this character appears unrelated to phylogeny. Thus, although the denitrifying community of soils may differ in their propensity to emit N2O, it may be difficult to predict such characteristics by analysis of the community composition. A common feature of strains tested in our laboratory is that the relative amounts of N2O produced (N2O/(N2+N2O) product ratio) is correlated with acidity, apparently owing to interference with the assembly of the enzyme N2O reductase. The same phenomenon was demonstrated for soils and microbial communities extracted from soils. Liming could be a way to reduce N2O emissions, but needs verification by field experiments. More sophisticated ways to reduce emissions may emerge in the future as we learn more about the regulation of denitrification at the cellular level

Low-mass dark matter search results from full exposure of PandaX-I experiment

We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1\;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6\%. With a fiducial liquid xenon target mass of 54.0\,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10\,GeV/c$^2$, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.Comment: v3 as accepted by PRD. Minor update in the text in response to referee comments. Separating Fig. 11(a) and (b) into Fig. 11 and Fig. 12. Legend tweak in Fig. 9(b) and 9(c) as suggested by referee, as well as a missing legend for CRESST-II legend in Fig. 12 (now Fig. 13). Same version as submitted to PR

Batch-produced, GIS-informed range maps for birds based on provenanced, crowd-sourced data inform conservation assessments.

Accurate maps of species ranges are essential to inform conservation, but time-consuming to produce and update. Given the pace of change of knowledge about species distributions and shifts in ranges under climate change and land use, a need exists for timely mapping approaches that enable batch processing employing widely available data. We develop a systematic approach of batch-processing range maps and derived Area of Habitat maps for terrestrial bird species with published ranges below 125,000 km2 in Central and South America. (Area of Habitat is the habitat available to a species within its range.) We combine existing range maps with the rapidly expanding crowd-sourced eBird data of presences and absences from frequently surveyed locations, plus readily accessible, high resolution satellite data on forest cover and elevation to map the Area of Habitat available to each species. Users can interrogate the maps produced to see details of the observations that contributed to the ranges. Previous estimates of Areas of Habitat were constrained within the published ranges and thus were, by definition, smaller-typically about 30%. This reflects how little habitat within suitable elevation ranges exists within the published ranges. Our results show that on average, Areas of Habitat are 12% larger than published ranges, reflecting the often-considerable extent that eBird records expand the known distributions of species. Interestingly, there are substantial differences between threatened and non-threatened species. Some 40% of Critically Endangered, 43% of Endangered, and 55% of Vulnerable species have Areas of Habitat larger than their published ranges, compared with 31% for Near Threatened and Least Concern species. The important finding for conservation is that threatened species are generally more widespread than previously estimated

A review of high impact weather for aviation meteorology

This review paper summarizes current knowledge available for aviation operations related to meteorology and provides suggestions for necessary improvements in the measurement and prediction of weather-related parameters, new physical methods for numerical weather predictions (NWP), and next-generation integrated systems. Severe weather can disrupt aviation operations on the ground or in-flight. The most important parameters related to aviation meteorology are wind and turbulence, fog visibility, aerosol/ash loading, ceiling, rain and snow amount and rates, icing, ice microphysical parameters, convection and precipitation intensity, microbursts, hail, and lightning. Measurements of these parameters are functions of sensor response times and measurement thresholds in extreme weather conditions. In addition to these, airport environments can also play an important role leading to intensification of extreme weather conditions or high impact weather events, e.g., anthropogenic ice fog. To observe meteorological parameters, new remote sensing platforms, namely wind LIDAR, sodars, radars, and geostationary satellites, and in situ instruments at the surface and in the atmosphere, as well as aircraft and Unmanned Aerial Vehicles mounted sensors, are becoming more common. At smaller time and space scales (e.g., < 1 km), meteorological forecasts from NWP models need to be continuously improved for accurate physical parameterizations. Aviation weather forecasts also need to be developed to provide detailed information that represents both deterministic and statistical approaches. In this review, we present available resources and issues for aviation meteorology and evaluate them for required improvements related to measurements, nowcasting, forecasting, and climate change, and emphasize future challenges