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Food flows between counties in the United States

ENVIRONMENTAL RESEARCH LETTERS 2019年第8期14卷 084011-084011页

作者： Lin, Xiaowen Ruess, Paul J. Marston, Landon Konar, Megan Univ Illinois Dept Civil & Environm Engn Urbana IL 61801 USA Kansas State Univ Dept Civil & Environm Engn Manhattan KS 66506 USA

Food consumption and production are separated in space through flows of food along complex supply chains. These food supply chains are critical to our food security, making it important to evaluate them. However, detailed spatial information on food flows within countries is rare. The goal of this paper is to estimate food flows between all county pairs within the United States. To do this, we develop the Food Flow Model, a data-driven methodology to estimate spatially explicit food flows. The Food Flow Model integrates machine learning, network properties, production and consumption statistics, mass balance constraints, and linear programming. Specifically, we downscale empirical information on food flows between 132 Freight Analysis Framework locations (17 292 potential links) to the 3142 counties and county-equivalents of the United States (9869 022 potential links). Subnational food flow estimates can be used in future work to improve our understanding of vulnerabilities within a national food supply chain, determine critical infrastructures, and enable spatially detailed footprint assessments.

关键词： food flows networks algorithm development

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Real-Time Detection of Daytime and Night-Time Fire Hotspots from Geostationary Satellites

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REMOTE SENSING 2021年第9期13卷 1627-1627页

作者： Engel, Chermelle B. Jones, Simon D. Reinke, Karin J. RMIT Univ STEM Coll Melbourne Vic 3000 Australia Bushfire & Nat Hazards Cooperat Res Ctr East Melbourne Vic 3002 Australia

This paper introduces an enhanced version of the Biogeographical Region and Individual Geostationary HHMMSS Threshold (BRIGHT) algorithm. The algorithm runs in real-time and operates over 24 h to include both daytime and night-time detections. The algorithm was executed and tested on 12 months of Himawari-8 data from 1 April 2019 to 31 March 2020, for every valid 10-min observation. The resulting hotspots were compared to those from the Visible Infrared Imaging Radiometer Suite (VIIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS). The modified BRIGHT hotspots matched with fire detections in VIIRS 96% and MODIS 95% of the time. The number of VIIRS and MODIS hotspots with matches in the coincident modified BRIGHT dataset was lower (at 33% and 46%, respectively). This paper demonstrates a clear link between the number of VIIRS and MODIS hotspots with matches and the minimum fire radiative power considered.

关键词： Advanced Himawari-Imager algorithm development clear-sky cloud detection fire anomaly fire detection geostationary Himawari-8

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Accelerating imaging frequency in high-speed polarization imaging through data modeling

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OPTICAL ENGINEERING 2024年第4期63卷 043103-043103页

作者： Timofeeva, Anastasia Ul Shougat, Md Raf E. Pankow, Mark Peters, Kara North Carolina State Univ Dept Mech & Aerosp Engn Raleigh NC 27695 USA

We develop a new processing algorithm for the analysis of high-speed quantitative polarized light microscopy measurements. The measurements are obtained using a high-speed rotating polarizing component and a camera, collecting images at several polarizer angles per rotation. The technique uses data from less than the full quarter-waveplate rotation and then performs an optimal fit of the measured data to the expected response curves. Thus, it allows to increase the effective frame rate of the alignment angle and retardation maps due to the reduction in required images. Due to the complexity of the intensity response curves, a particle swarm optimization method is applied. The algorithm addresses the motion error in high-speed polarization imaging while still using multiple polarization angles for the reconstruction. We apply the algorithm to two example cases: quasi-static loading of a tensile coupon and quality inspection of a polymer fiber during rapid motion. The results demonstrate that increasing the reconstructions per second (i.e., decreasing the number of polarization angles per reconstruction) does not significantly decrease the quality of the reconstructions until similar to 2.5 times the increase in reconstructions per second is achieved. Therefore, the developed algorithm is an effective method to increase the effective polarization imaging rate without complex hardware modifications.

关键词： polarization imaging birefringence optimization algorithm development

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Hyperspectral retrievals of phytoplankton absorption and chlorophyll-a in inland and nearshore coastal waters

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REMOTE SENSING OF ENVIRONMENT 2021年 253卷 112200-112200页

作者： Pahlevan, Nima Smith, Brandon Binding, Caren Gurlin, Daniela Li, Lin Bresciani, Mariano Giardino, Claudia NASA Goddard Space Flight Ctr Greenbelt MD 20771 USA Sci Syst & Applicat Inc SSAI Lanham MD USA Environm & Climate Change Canada Burlington ON Canada Wisconsin Dept Nat Resources Madison WI USA Indiana Univ Purdue Univ Purdue Sch Sci Indianapolis IN 46202 USA Natl Res Council Italy IREA Milan Italy

Following more than two decades of research and developments made possible through various proof-of-concept hyperspectral remote sensing missions, it has been anticipated that hyperspectral imaging would enhance the accuracy of remotely sensed in-water products. This study investigates such expected improvements and demonstrates the utility of hyperspectral radiometric measurements for the retrieval of near-surface phytoplankton properties(1), i.e., phytoplankton absorption spectra (a(ph)) and biomass evaluated through examining the concentration of chlorophyll-a (Chla). Using hyperspectral data (409-800 nm at similar to 5 nm resolution) and a class of neural networks known as Mixture Density Networks (MDN) (Pahlevan et al., 2020), we show that the median error in a(ph) retrievals is reduced two-to-three times (N = 722) compared to that from heritage ocean color algorithms. The median error associated with our a(ph) retrieval across all the visible bands varies between 20 and 30%. Similarly, Chla retrievals exhibit significant improvements (i.e., more than two times;N = 1902), with respect to existing algorithms that rely on select spectral bands. Using an independent matchup dataset acquired near-concurrently with the acquisition of the Hyperspectral Imager for the Coastal Ocean (HICO) images, the models are found to perform well, but at reduced levels due to uncertainties in the atmospheric correction. The mapped spatial distribution of Chla maps and a(ph) spectra for selected HICO swaths further solidify MDNs as promising machine-learning models that have the potential to generate highly accurate aquatic remote sensing products in inland and coastal waters. For a(ph) retrieval to improve further, two immediate research avenues are recommended: a) the network architecture requires additional optimization to enable a simultaneous retrieval of multiple in-water parameters (e.g., a(ph), Chla, absorption by colored dissolved organic matter), and b) the training datase

关键词： Hyperspectral Inland and coastal waters HICO Phytoplankton absorption Chlorophyll-a Machine learning algorithm development

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EPypes: a framework for building event-driven data processing pipelines

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PEERJ COMPUTER SCIENCE 2019年第2期5卷 e176页

作者： Semeniuta, Oleksandr Falkman, Petter NTNU Norwegian Univ Sci & Technol Dept Mfg & Civil Engn Gjovik Norway Chalmers Univ Technol Dept Elect Engn Gothenburg Sweden

Many data processing systems are naturally modeled as pipelines, where data flows though a network of computational procedures. This representation is particularly suitable for computer vision algorithms, which in most cases possess complex logic and a big number of parameters to tune. In addition, online vision systems, such as those in the industrial automation context, have to communicate with other distributed nodes. When developing a vision system, one normally proceeds from ad hoc experimentation and prototyping to highly structured system integration. The early stages of this continuum are characterized with the challenges of developing a feasible algorithm, while the latter deal with composing the vision function with other components in a networked environment. In between, one strives to manage the complexity of the developed system, as well as to preserve existing knowledge. To tackle these challenges, this paper presents EPypes, an architecture and Python-based software framework for developing vision algorithms in a form of computational graphs and their integration with distributed systems based on publish-subscribe communication. EPypes facilitates flexibility of algorithm prototyping, as well as provides a structured approach to managing algorithm logic and exposing the developed pipelines as a part of online systems.

关键词： Computer vision Computational graph Publish-subscribe Robotics Python Pipeline Distributed systems algorithm development Event-driven systems Concurrency

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IMUs Can Estimate Hip and Knee Range of Motion during Walking Tasks but Are Not Sensitive to Changes in Load or Grade

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SENSORS 2024年第5期24卷 1675页

作者： Fain, AuraLea McCarthy, Ayden Nindl, Bradley C. Fuller, Joel T. Wills, Jodie A. Doyle, Tim L. A. Macquarie Univ Biomech Dept Hlth Med & Human Sci Biomech Phys Performance & Exercise Res Grp Sydney NSW 2113 Australia Univ Pittsburgh Neuromuscular Res Lab Warrior Human Performance Res Ctr Dept Sports Med & Nutr Pittsburgh PA 15260 USA

The ability to estimate lower-extremity mechanics in real-world scenarios may untether biomechanics research from a laboratory environment. This is particularly important for military populations where outdoor ruck marches over variable terrain and the addition of external load are cited as leading causes of musculoskeletal injury As such, this study aimed to examine (1) the validity of a minimal IMU sensor system for quantifying lower-extremity kinematics during treadmill walking and running compared with optical motion capture (OMC) and (2) the sensitivity of this IMU system to kinematic changes induced by load, grade, or a combination of the two. The IMU system was able to estimate hip and knee range of motion (ROM) with moderate accuracy during walking but not running. However, SPM analyses revealed IMU and OMC kinematic waveforms were significantly different at most gait phases. The IMU system was capable of detecting kinematic differences in knee kinematic waveforms that occur with added load but was not sensitive to changes in grade that influence lower-extremity kinematics when measured with OMC. While IMUs may be able to identify hip and knee ROM during gait, they are not suitable for replicating lab-level kinematic waveforms.

关键词： inertial measurement units wearable sensors kinematics algorithm development

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Mapping remote rural settlements at 30 m spatial resolution using geospatial data-fusion

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REMOTE SENSING OF ENVIRONMENT 2019年 233卷 111386-000页

作者： Hoffman-Hall, Amanda Loboda, Tatiana V. Hall, Joanne V. Carroll, Mark L. Chen, Dong Univ Maryland Dept Geog Sci 2181 LeFrak Hall7251 Preinkert Dr College Pk MD 20742 USA NASAs Goddard Space Flight Ctr 8800 Greenbelt Rd Greenbelt MD 20771 USA

Accurate and timely population distribution maps are critical to addressing health epidemics, coordinating natural disaster response, tracking global changes for environmental conservation, confronting human rights issues, and more. Satellite imagery has opened numerous ways for mapping population distribution - previously unattainable without conducting a resource intensive census. While great advances have been made in urban population mapping, large gaps still exist for rural and remote populations which tend to be the most vulnerable to environmental, economic, and socio-political change. Moderate resolution remote sensing data, such as Landsat, has generally been viewed as insufficient for rural mapping given its coarseness relative to the size of a rural dwelling. This paper presents an approach for detecting small rural settlements within Ann Township of Rakhine State, a remote region of Myanmar with a highly mobile population, by combining Landsat data with publicly available auxiliary geospatial data. The key to the success of detecting small settlements at the Landsat resolution was the inclusion of multi-temporal auxiliary data sensitive to human activity patterns in the regions, such as distance to water, change in seasonal vegetation signals, and distance to a recent active fire. The use of active fire in this context is novel and provided a key metric that increased the accuracy of the resultant map. The final dataset has a classification accuracy of 86.5% on a per-pixel basis and 93.1% on a location identification basis. Numerous small settlements (on the order of 2-3 structures in some cases) not previously mapped by other datasets are identified, revealing that the population of Ann Township is far more dispersed and isolated than previously mapped. This study concludes that by incorporating regionally specific characteristics, moderate resolution remotely sensed data can be used to successfully map geographically marginalized communities so that se

关键词： Landsat Rural Population mapping Settlement Image classification algorithm development Myanmar Moderate resolution Place Land use

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Cost-based closed-contour representations

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JOURNAL OF ELECTRONIC IMAGING 2007年第2期16卷 023009.1-023009.9页

作者： Sappa, Angel D. Vintimilla, Boris X. Comp Vis Ctr Barcelona 08193 Spain Escuela Super Politecn Litoral Dept Elect Engn & Comp Sci Vis & Robot Ctr Guayaquil 09015863 Ecuador

This paper presents an efficient technique for linking edge points in order to generate a closed-contour representation. It is based on the consecutive use of global and local schemes. In both cases it is assumed that the original intensity image, as well as its corresponding edge map, are given as inputs to the algorithm. The global scheme computes an initial representation by connecting edge points minimizing a global measure based on spatial information (3D space). It relies on the use of graph theory and exploits the edge points' distribution through the given edge map, as well as their corresponding intensity values. At the same time spurious edge points are removed by a morphological filter The local scheme finally generates closed contours, linking open boundaries, by using a local cost function that takes into account both spatial and topological information. Experimental results with different images, together with comparisons with a previous technique, are presented. (C) 2007 SPIE and IS&T.

关键词： Image segmentation Image processing Image filtering Image processing algorithms and systems Sensors 3D image processing Detection and tracking algorithms algorithm development Edge detection Visualization

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More Than a Paper

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OPTICAL ENGINEERING 2019年第5期58卷 050101-050101页

作者： Eismann, Michael T.

Editor-in-Chief Mike Eismann writes about supplemental materials in scientific journals.

关键词： Optical engineering Computer programming Video algorithm development Computer programming languages Scientific research Analytics Data processing Process control Software development

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Informing Stochastic Streamflow Generation by Large-Scale Climate Indices at Single and Multiple Sites

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ADVANCES IN WATER RESOURCES 2021年 156卷

作者： Zaerpour, Masoud Papalexiou, Simon Michael Nazemi, Ali Concordia Univ Dept Bldg Civil & Environm Engn Montreal PQ Canada Univ Calgary Dept Civil Engn Calgary AB Canada Univ Saskatchewan Dept Civil Geol & Environm Engn Saskatoon SK Canada

Despite the existence of several stochastic streamflow generators, not much attention has been given to representing the impacts of large-scale climate indices on seasonal to interannual streamflow variability. By merging a formal predictor selection scheme with vine copulas, we propose a generic approach to explicitly incorporate large-scale climate indices in ensemble streamflow generation at single and multiple sites and in both short-term prediction and long-term projection modes. The proposed framework is applied at three headwater streams in the Oldman River Basin in southern Alberta, Canada. The results demonstrate higher skills than existing models both in terms of representing intra- and inter-annual variability, as well as accuracy and predictability of streamflow, particularly during high flow seasons. The proposed algorithm presents a globally relevant scheme for the stochastic streamflow generation, where the impacts of large-scale climate indices on streamflow variability across time and space are significant.

关键词： Streamflow variability Large-scale climate indices Stochastic streamflow generation Predictor selection Vine copulas algorithm development

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