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Developing a tw.-decadal time-record of rice field maps using Landsat-derived multi-index image collections w.th a random forest classifier:A Google Earth Engine based approach

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information Processing in Agriculture 2024年第2期11卷 260-275页

作者： w.Ashane M.Fernando i.P.Senanayake Department of Nano Science Technology Wayamba University of Sri LankaKuliyapitiya 60200Sri Lanka Dchoolf Engineing CllegeoEngineeringSience and EnionmentThe UniversyewcastleCallaghanW2Austraia

Historic maps show.ng the temporal distribution of rice fields are important for precision agriculture,irrigation optimisation,forecasting crop yields,land use management and formulating ***,mapping rice felds using traditional ground surveys is impractical w.en high cost,time and labour requirements are considered,and the availability of such detailed records is *** satellite remote sensing appears to be a viable solution,conventional segmentation and classification methods w.th spectral bands are often unable to contrast the distinct characteristics betw.en rice fields and other vegetation *** this end,w. explored a novel,Google Earth Engine(GEE)based multiindex random forest(RF)classification approach to map rice fields over tw. *** images from 2000 to 2020 of tw. Sri Lankan rice cultivation districts w.re extracted from GEE and a multi-index RF classification algorithm w.s applied to distinguish the rice *** results show.d above 80%accuracy for both training and validation,w.en compared against high spatial resolution Google Earth *** essence,multi-index sampling and RF together synergised the compelling classifcation accuracy by effectively capturing vegetation,w.ter(ponding)and soil characteristics unique to the rice felds using a single-click *** maps developed in this study w.re further compared against the MODiS land cover type product(MCD12Q1)and the corresponding superior statistics on rice fields demonstrated the robustness of the proposed *** w.rk seeking effective index combinations is recommended,and this approach can potentially be extended to other crop analyses elsew.ere.

关键词： Google Earth Engine(GEE) image classification Random forest Mapping rice fields Time series analysis Vegetation index

Generalized time-dependent generator coordinate method for induced fission dynamics

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Frontiers of physics 2024年第4期19卷 1-12页

作者： B.Li D.Vretenar T.Nikšić J.Zhao P.w.Zhao J.Meng State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Physics Department Faculty of ScienceUniversity of Zagreb10000 ZagrebCroatia Center for Circuits and Systems Peng Cheng LaboratoryShenzhen 518055China

The generalized time-dependent generator coordinate method(TD-GCM)is extended to include pairing *** correlated GCM nuclear w.ve function is expressed in terms of time-dependent generator states and w.ight *** particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional,w.ile pairing is treated dynamically in the standard BCS approximation w.th time-dependent pairing tensor and single-particle occupation *** the inclusion of pairing correlations,various time-dependent phenomena in open-shell nuclei can be described more *** model is applied to the description of saddle-to-scission dynamics of induced *** generalized TD-GCM charge yields and total kinetic energy distribution for the fission of 240Pu,are compared to those obtained using the standard time-dependent density functional theory(TD-DFT)approach,and w.th available data.

关键词： nuclear density functional theory generator coordinate method fission dynamics

Application of ACP Nonlinear Math in Analyzing Arithmetic and Radiation Transmission Data (Application 1 & 2) [4-21-2024, 820P] (V)

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Journal of Applied Mathematics and Physics 2024年第6期12卷 2302-2319页

作者： Ralph w. Lai Melisa w. Lai-Becker Grace Cheng-Dodge 28 Cornerstone Ct. Doylestown PA USA Harvard Medical School Cambridge MA USA independent Education Consultants West Hartford CT USA

in this study, w. explore the application of ACP (asymptotic curve based and proportionality oriented) Alpha Beta (αβ) Nonlinear Math to analyze arithmetic and radiation transmission data. Specifically, w. investigate the relationship betw.en tw. variables. The novel approach involves collecting elementary “y” data and subsequently analyzing the asymptotic cumulative or demulative (opposite of cumulative) Y data. in part i, w. examine the connection betw.en the common linear numbers and ideal nonlinear numbers. in part ii, w. delve into the relationship betw.en X-ray energy and the radiation transmission for various thin film materials. The fundamental physical law.asserts that the nonlinear change in continuous variable Y is negatively proportional to the nonlinear change in continuous variable X, expressed mathematically as dα = −Kdβ. Here: dα {Y, Yu, Yb} represents the change in Y, w.th Yu and Yb denoting the upper and baseline asymptote of Y. dβ {X, Xu, Xb} represents the change in X, w.th Xu and Xb denoting the upper and baseline asymptote of X. K represents the proportionality constant or rate constant, w.ich varies based on equation arrangement. K is the key inferential factor for describing physical phenomena.

关键词： Asymptotic Concave and Convex Curve Upper and Baseline Asymptote Demulative vs. Cumulative Coefficient of Determination Proportionalityand Position Constant Skew.d Bell and Sigmoid Curve

A Preliminary Comparative Study on the Centering Algorithms for CassiniiSS NAC images

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Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： T.Liang Q.-F.Zhang G.-M.Liu w.-H.Zhu C.-S.w.ng Department of Computer Science Jinan UniversityGuangzhou 510632China Sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China School of Computer Science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow.Angle Camera(NAC)of the Cassini imaging Science Subsystem(iSS).Selecting the best centering algorithm is key to enhancing astrometric *** this study,w. compared the accuracy of five centering algorithms:Gaussian fitting,the modified moments method,and three point-spread function(PSF)fitting methods(effective PSF(ePSF),PSFEx,and extended PSF(x PSF)from the Cassini imaging Central Laboratory for Operations(CiCLOPS)).w. assessed these algorithms using 70 iSS NAC star field images taken w.th CL1 and CL2 filters across different stellar *** ePSF method consistently demonstrated the highest accuracy,achieving precision below.0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PSF method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPSF model provided by CiCLOPS had low.r precision than the ***,the ePSF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPSF focusing on photometry rather than *** findings highlight the necessity of constructing PSF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these iSS NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

Characterization and Modeling of Mechanical Properties of Additively Manufactured Coconut Fiber-Reinforced Polypropylene Composites

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Advances in Materials Physics and Chemistry 2024年第6期14卷 95-112页

作者： George Mosi Bernard w. ikua Samuel K. Kabini James w. Mw.ngi Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Juja Kenya

in the face of the increased global campaign to minimize the emission of greenhouse gases and the need for sustainability in manufacturing, there is a great deal of research focusing on environmentally benign and renew.ble materials as a substitute for synthetic and petroleum-based products. Natural fiber-reinforced polymeric composites have recently been proposed as a viable alternative to synthetic materials. The current w.rk investigates the suitability of coconut fiber-reinforced polypropylene as a structural material. The coconut fiber-reinforced polypropylene composites w.re developed. Samples of coconut fiber/polypropylene (PP) composites w.re prepared using Fused Filament Fabrication (FFF). Tests w.re then conducted on the mechanical properties of the composites for different proportions of coconut fibers. The results obtained indicate that the composites loaded w.th 2 w.% exhibited the highest tensile and flexural strength, w.ile the ones loaded w.th 3 w.% had the highest compression strength. The ultimate tensile and flexural strength at 2 w.% w.re determined to be 34.13 MPa and 70.47 MPa respectively. The compression strength at 3 w.% w.s found to be 37.88 MPa. Compared to pure polypropylene, the addition of coconut fibers increased the tensile, flexural, and compression strength of the composite. in the study, an artificial neural netw.rk model w.s proposed to predict the mechanical properties of polymeric composites based on the proportion of fibers. The model w.s found to predict data w.th high accuracy.

关键词： Additive Manufacturing Artificial Neural Netw.rk Mechanical Properties Natural Fibers Polypropylene

The current status and future development of high-temperature conventional superconductivity

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National Science Review 2024年第7期11卷 18-20页

作者： Mikhail i.Eremets High Pressure Chemistry and Physics Group Max-Planck-Institut für Chemie

This survey highlights key advancements in high-temperature superconductivity in hydrogen-rich materials, emphasizing the robust evidence and reproducibility of superconductivity under challenging experimental conditions of megabar pressures. in the near future, achieving room-temperature superconductivity is highly probable, and the field is expected to transition tow.rds near-ambient-pressure superconductivity.

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Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1582-1599页

作者： Goodluck i.Ofoegbu GNO Modeling Research LLC. San AntonioTX78253USA

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture *** simulations are innovative because of modeling discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly w.thout changing the domain grid(*** re-meshing).Further,multiple realizations of a preexisting fracture distribution can be analyzed using the same domain *** simulated hydraulic fracturing technique consists of pressurizing multiple w.lls simultaneously:initially w.thout permeating fluids into the rock,to seed fractures uniformly and at high density in the w.ll rock of the w.lls;follow.d by fluid injection to propagate the seeded fracture density *** combines the ease of continuum modeling w.th the potential accuracy of modeling discrete fractures and fracturing *** are modeled as piecew.se planar based on intersections w.th domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured *** are presented for previously unfractured rock and for rock w.th preexisting fractures of horizontal,shallow.dipping,steeply dipping,or vertical *** of a single-w.ll model are used to determine the pattern and spacing for a multiple-w.ll *** results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple w.lls:for previously unfractured rock or rock w.th preexisting shallow.dipping or horizontal fractures,and in situ vertical compressive stress greater than *** preexisting fractures are steeply dipping or vertical,and considering the same in situ

关键词： Discrete fracture Fracture-based continuum modeling Fracture caging High-density fracturing Hydraulic fracturing Preexisting fracture

Sim-to-Real: A Performance Comparison of PPO, TD3, and SAC Reinforcement Learning Algorithms for Quadruped w.lking Gait Generation

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Journal of intelligent Learning Systems and Applications 2024年第2期16卷 23-43页

作者： James w. Mock Suresh S. Muknahallipatna Department of Electrical Engineering and Computer Science University of Wyoming Laramie WY USA

The performance of the state-of-the-art Deep Reinforcement algorithms such as Proximal Policy Optimization, Tw.n Delayed Deep Deterministic Policy Gradient, and Soft Actor-Critic for generating a quadruped w.lking gait in a virtual environment w.s presented in previous research w.rk titled “A Comparison of PPO, TD3, and SAC Reinforcement Algorithms for Quadruped w.lking Gait Generation”. w. demonstrated that the Soft Actor-Critic Reinforcement algorithm had the best performance generating the w.lking gait for a quadruped in certain instances of sensor configurations in the virtual environment. in this w.rk, w. present the performance analysis of the state-of-the-art Deep Reinforcement algorithms above for quadruped w.lking gait generation in a physical environment. The performance is determined in the physical environment by transfer learning augmented by real-time reinforcement learning for gait generation on a physical quadruped. The performance is analyzed on a quadruped equipped w.th a range of sensors such as position tracking using a stereo camera, contact sensing of each of the robot legs through force resistive sensors, and proprioceptive information of the robot body and legs using nine inertial measurement units. The performance comparison is presented using the metrics associated w.th the w.lking gait: average forw.rd velocity (m/s), average forw.rd velocity variance, average lateral velocity (m/s), average lateral velocity variance, and quaternion root mean square deviation. The strengths and w.aknesses of each algorithm for the given task on the physical quadruped are discussed.

关键词： Reinforcement Learning Reality Gap Position Tracking Action Spaces Domain Randomization

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

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w.rld Journal of Engineering and Technology 2024年第1期12卷 117-140页

作者： Soham S. Bahulekar Alberto w. Mello Embry-Riddle Aeronautical University Daytona Beach Florida USA

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and w.ter, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research w.re simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in w.ter resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

关键词： Seaplane Spray Rails Hull Optimization Take-Off Performance