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Seismic simultaneous inversion using a multidamped subspace method

GEOPHYSICS 2020年第1期85卷 R1-R10页

作者： Liu, Jinyue Wang, Yanghua Imperial Coll London Dept Earth Sci & Engn Ctr Reservoir Geophys London SW7 2BP England Imperial Coll London Dept Earth Sci & Engn Resource Geophys Acad Ctr Reservoir Geophys London SW7 2BP England

Seismic inversion of amplitude variation with offset (AVO) plays a key role in seismic interpretation and reservoir characterization. The AVO inversion should be a simultaneous inversion that inverts for three elastic parameters simultaneously: the P-wave impedance, S-wave impedance, and density. Using only seismic P-wave reflection data with a limited source-receiver offset range, the AVO simultaneous inversion can obtain two elastic parameters reliably, but it is difficult to invert for the third parameter, usually the density term. To address this difficulty in the AVO simultaneous inversion, we used a subspace inversion method in which we partitioned the elastic parameters into different subspaces. We parameterized each single elastic parameter with a truncated Fourier series and inverted for the Fourier coefficients. Because the Fourier coefficients of different wavenumber components have different sensitivities, we grouped the Fourier coefficients of low-, medium-, and high-wavenumber components into different subspaces. We further assigned different damping factors to the Hessian matrix corresponding to different wavenumber components within each subspace. This inversion scheme is referred to as a multidamped subspace method. Synthetic and field seismic data examples confirmed that the AVO simultaneous inversion with this multidamped subspace method is capable of producing reliable estimation of the three elastic parameters simultaneously.

关键词： AVO inversion damping scheme elastic parameters Fourier coefficients model parameterization subspace method

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Data, depth, and design: Learning reliable models for skin lesion analysis

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NEUROCOMPUTING 2020年 383卷 303-313页

作者： Valle, Eduardo Fornaciali, Michel Menegola, Afonso Tavares, Julia Bittencourt, Flavia Vasques Li, Lin Tzy Avila, Sandra Univ Campinas UNICAMP Sch Elect & Comp Engn Av Albert Einstein 400 BR-13083852 Campinas SP Brazil Fed Univ Minas Gerais UFMG Sch Med Alamedalvaro Celso 55 BR-30150260 Belo Horizonte MG Brazil Univ Campinas UNICAMP Inst Comp Av Albert Einstein 1251 BR-13083852 Campinas SP Brazil Samsung R&D Inst Brazil SRBR Campinas SP Brazil

Deep learning fostered a leap ahead in automated skin lesion analysis in the last two years. Those models, however, are expensive to train and difficult to parameterize. Objective: We investigate methodological issues for designing and evaluating deep learning models for skin lesion analysis. We explore ten choices faced by researchers: use of transfer learning, model architecture, train dataset, image resolution, type of data augmentation, input normalization, use of segmentation, duration of training, additional use of Support Vector Machines, and test data augmentation. Methods: We perform two full factorial experiments, for five different test datasets, resulting in 2560 exhaustive trials in our main experiment, and 1280 trials in our assessment of transfer learning. We analyze both with multi-way analyses of variance (ANOVA). We use the exhaustive trials to simulate sequential decisions and ensembles, with and without the use of privileged information from the test set. Results main experiment: Amount of train data has disproportionate influence, explaining almost half the variation in performance. Of the other factors, test data augmentation and input resolution are the most influential. Deeper models, when combined, with extra data, also help. - transfer experiment: Transfer learning is critical, its absence brings huge performance penalties. - simulations: Ensembles of models are the best option to provide reliable results with limited resources, without using privileged information and sacrificing methodological rigor. Conclusions and Significance: Advancing research on automated skin lesion analysis requires curating larger public datasets. Indirect use of privileged information from the test set to design the models is a subtle, but frequent methodological mistake that leads to overoptimistic results. Ensembles of models are a cost-effective alternative to the expensive full-factorial and to the unstable sequential designs. (C) 2019 Elsevier B.V. All righ

关键词： Skin lesion analysis Deep learning Experimental design model parameterization Cross dataset

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Dynamic parameterization of soil surface characteristics for hydrological models in agricultural catchments

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CATENA 2022年 214卷

作者： Grangeon, Thomas Vandromme, Rosalie Pak, Lai Ting Martin, Philippe Cerdan, Olivier Richet, Jean-Baptiste Evrard, Olivier Souchere, Veronique Auzet, Anne-Veronique Ludwig, Bruno Ouvry, Jean-Francois Bur Rech Geol & Minieres F-45060 Orleans France Cirad F-97285 Le Lamentin Martinique France Assoc Rech Ruissellement Eros & Amenagement Sol AR 2 Ave Foch F-76460 St Valery En Caux France Univ Paris Saclay INRAE AgroParisTech UMR SADAPT F-75005 Paris France Univ Paris Saclay Lab Sci Climat & Environm LSCE IPSL UMR 8212 CEACNRSUVSQ Gif Sur Yvette France Univ Paris Saclay UMR SADAPT INRAE AgroParisTech Ave Lucien Bretignieres F-78850 Thiverval Grignon France Univ Strasbourg ITES UMR 7063 F-67084 Strasbourg France LIOSE 71 Rue Crecy F-02000 Laon France

The detrimental impacts of surface runoff and soil erosion, particularly in cultivated areas, call for the use of distributed runoff and soil erosion models with a view to supporting adapted catchment management strategies. However, runoff model parameterization remains challenging in agricultural catchments due to the high spatial and seasonal variability of soil properties. Data acquisition is demanding and may not always be feasible. Therefore, model parameterization in such environments have been the subject of numerous research efforts. The combined analysis of land use management and soil surface state was proposed in literature to address this issue and demonstrated its potential for runoff analysis and modelling. However, these research findings were related to specific rainfall sequences and/or soil surface state. In this study, existing knowledge on soil surface state and its application to runoff model parameterization were synthetized and included in an easy-to-use parameterization software (PREMACHE), providing a framework for modelers lacking of means and/or data for modelling complex agricultural *** develop and evaluate the software, a dataset was acquired over 9 years on more than 110 plots in a 1045 ha agricultural catchment, including crop types, soil surface state, rainfall and runoff time series. Soil surface state dynamics was modeled based on crop types and daily rainfall. It was evaluated in the experimental catchment and validated in a nearby catchment. Soil hydrodynamic properties (e.g. infiltration capacity) were deduced from this framework and literature data at a daily time step, for each plots. Moreover, runoff events were measured when the modeled infiltration capacity was low, indicating that the parametrization adequately captured its temporal dynamics. The software developed in this study, as well as setup values deduced from the monitoring campaigns are provided with the manuscript for application in other ungauged catchm

关键词： Crops Soil properties Runoff Agricultural catchment model parameterization Soil infiltration capacity Tillage operations

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Predictive modeling of plant uptake of Pb and Cd: Implications of aerial deposition and the origin of parameterisation data

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Environmental Challenges 2023年 12卷

作者： Lundgren, Maria Troldborg, Mads Stubberfield, Jon Augustsson, Anna Hough, Rupert Lloyd Linnaeus University Faculty of Health and Life Sciences Department of Biology and Environmental Science Universitetsplatsen 1 Kalmar 391 82 Sweden The James Hutton Institute Craigiebuckler Scotland Aberdeen AB15 8QH United Kingdom Environment Agency England Nottingham NG2 5FA United Kingdom

We developed ordinary least squares regression models to predict uptake of cadmium and lead, two metals that are of public health significance because of their toxicity, in the edible tissues of lettuce. models were parameterised using data on soil metal concentration, pH, and organic carbon. To assess the impact of physical contamination in form of aerial deposition and soil-splash on the metal concentration in lettuce, separate linear regression models were parameterised for indoor- and outdoor-grown lettuce, assuming the physical contamination to be negligible for indoor conditions. Both Cd models showed high model fit and strong predictive performance, when tested on an independent dataset, suggesting uptake via roots to be dominant. For Pb, the indoor model performed better than the outdoor model, indicating that physical contamination, contributes significantly to metal concentration in lettuce leaves. Our results highlight the importance of the parameterisation data when developing uptake models for predictions and risk assessment. Regression models for predicting Pb concentration in lettuce based on indoor data should not be used for predicting lettuce concentrations cultivated in outdoor conditions unless the contribution of physical contamination is explicitly accounted for. © 2023 The Author(s)

关键词： Contamination routes Metal uptake model evaluation model parameterization Predictive regression models Risk assessments Urban gardening

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Parameter estimation for functional-structural plant models when data are scarce: using multiple patterns for rejecting unsuitable parameter sets

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ANNALS OF BOTANY 2020年第4期126卷 559-570页

作者： Wang, Ming White, Neil Hanan, Jim He, Di Wang, Enli Cribb, Bronwen Kriticos, Darren J. Paini, Dean Grimm, Volker Commonwealth Sci & Ind Res Org CSIRO Hlth & Biosecur Canberra ACT 2601 Australia Univ Queensland Ctr Hort Sci Queensland Alliance Agr & Food Innovat QAAFI Brisbane Qld 4072 Australia Dept Agr & Fisheries Toowoomba Qld 4350 Australia Commonwealth Sci & Ind Res Org CSIRO Agr & Food Canberra ACT 2601 Australia Univ Queensland Ctr Microscopy & Microanal Brisbane Qld 4072 Australia Univ Queensland Sch Biol Sci Brisbane Qld 4072 Australia UFZ Helmholtz Ctr Environm Res Dept Ecol Modelling Permoserstr 15 D-04318 Leipzig Germany Univ Potsdam Dept Plant Ecol & Nat Conservat Muhlenberg 3 D-14476 Potsdam Germany

Background and Aims: Functional-structural plant (FSP) models provide insights into the complex interactions between plant architecture and underlying developmental mechanisms. However, parameter estimation of FSP models remains challenging. We therefore used pattern-oriented modelling (POM) to test whether parameterization of FSP models can be made more efficient, systematic and powerful. With POM, a set of weak patterns is used to determine uncertain parameter values. instead of measuring them in experiments or observations. which often is infeasible. Methods: We used an existing FSP model of avocado (Persea americana 'Hass') and tested whether POM parameterization would converge to an existing manual parameterization. The model was run for 10 000 parameter sets and model outputs were compared with verification patterns. Each verification pattern served as a filter for rejecting unrealistic parameter sets. The model was then validated by running it with the surviving parameter sets that passed all filters and then comparing their pooled model outputs with additional validation patterns that were not used for parameterization. Key Results: POM calibration led to 22 surviving parameter sets. Within these sets, most individual parameters varied over a large range. One of the resulting sets was similar to the manually parameterized set. Using the entire suite of surviving parameter sets, the model successfully predicted all validation patterns. However, two of the surviving parameter sets could not make the model predict all validation patterns. Conclusions: Our findings suggest strong interactions among model parameters and their corresponding processes, respectively. Using all surviving parameter sets takes these interactions into account fully, thereby improving model performance regarding validation and model output uncertainty. We conclude that POM calibration allows FSP models to be developed in a timely manner without having to rely on field or laboratory exper

关键词： Pattern-oriented modelling model calibration model parameterization functional-structural plant modelling simulation inference parameter estimation avocado Persea americana equifinality parameter identifiability agent-based modelling individual-based modelling

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Potential utility of geomagnetic data for geolocation of demersal fishes in the North Pacific Ocean

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ANIMAL BIOTELEMETRY 2020年第1期8卷 1-20页

作者： Nielsen, J. K. Mueter, F. J. Adkison, M. D. Loher, T. McDermott, S. F. Seitz, A. C. Univ Alaska Fairbanks Coll Fisheries & Ocean Sci 17101 Point Lena Loop Rd Juneau AK 99801 USA Kingfisher Marine Res LLC 1102 Wee Burn Dr Juneau AK 99801 USA Int Pacific Halibut Commiss 2320 Commodore Way Seattle WA 98199 USA NOAA Natl Marine Fisheries Serv Alaska Sci Ctr 7600 Sand Point Way Northeast Seattle WA 98115 USA Univ Alaska Fairbanks Coll Fisheries & Ocean Sci POB 757220 Fairbanks AK 99775 USA

BackgroundArchival tags that measure the Earth's magnetic field could provide a new geolocation method for demersal fishes in the North Pacific Ocean. However, the presence of local magnetic field anomalies caused by geological formations such as volcanic rock and temporal fluctuations from solar storms could complicate its use in some high-latitude areas of the North Pacific Ocean. We assessed the potential value of adding geomagnetic data to a depth-based state-space model for geolocation of demersal fishes in Glacier Bay National Park, USA, a high-latitude magnetic anomaly area. We developed a high-resolution (100 m) magnetic field map of the study area and assessed in situ tag resolution by deploying 5 geomagnetic archival tags on a stationary mooring for 8 months. We compared performance of 4 theoretical geomagnetic tag measurement resolutions (low=1000 nT, medium=500 nT, high=+/- 300 nT, and very high=+/- 150 nT), 2 map resolutions (coarse- or fine-scale), and 5 methods of geomagnetic variance specification by estimating locations of simulated random walk trajectories under the different treatment scenarios using a hidden Markov *** Geomagnetic data improved model performance for both fine-scale and coarse-scale magnetic maps when tag resolutions were medium to very high and geomagnetic variance specification was based on error between measured and mapped values instead of study area attributes such as slope or roughness. Overall, the best model performance was observed for the highest tag resolution, the fine-scale map, and variance based on anomaly magnitudes. However, the coarse-scale map with a constant variance of 165 nT resulted in improvements over depth alone for all tag resolutions. In situ testing of mooring data suggests that the precision of the geomagnetic archival tags was comparable to the low and medium tag measurement resolutions tested in simulations, but variation in performance was high among *** results suggest th

关键词： Fish geolocation Geomagnetic Archival tags Hidden Markov model Map resolution model parameterization

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Simple and Two-Level Hierarchical Bayesian Approaches for Parameter Estimation with One- and Two-Layer Evapotranspiration models of Crop Fields

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WATER 2021年第24期13卷

作者： Shiraki, Shutaro Thu, Aung Kyaw Matsuno, Yutaka Shinogi, Yoshiyuki Japan Int Res Ctr Agr Sci Rural Dev Div 1-1 Owashi Tsukuba Ibaraki 3058686 Japan Minist Agr Livestock & Irrigat Dept Agr Res Naypyitaw 15013 Myanmar Kinki Univ Fac Agr Dept Environm Management 3327-204 Nakamachi Nara 6318505 Japan Kyushu Univ Fac Agr Dept Agroenvironm Sci Nishi Ku 744 Motooka Fukuoka 8190395 Japan

The two-layer Shuttleworth-Wallace (SW) evapotranspiration (ET) model has been widely used for predicting ET with good results. Since the SW model has a large number of specific parameters, these parameters have been estimated using a simple non-hierarchical Bayesian (SB) approach. To further improve the performance of the SW model, we aimed to assess parameter estimation using a two-level hierarchical Bayesian (HB) approach that takes into account the variation in observed conditions through the comparison with a traditional one-layer Penman-Monteith (PM) model. The difference between the SB and HB approaches were evaluated using a field-based ET dataset collected from five agricultural fields over three seasons in Myanmar. For a calibration period with large variation in environmental factors, the models with parameters calibrated by the HB approach showed better fitting to observed ET than that with parameters estimated using the SB approach, indicating the potential importance of accounting for seasonal fluctuations and variation in crop growth stages. The validation of parameter estimation showed that the ET estimation of the SW model with calibrated parameters was superior to that of the PM model, and the SW model provided acceptable estimations of ET, with little difference between the SB and HB approaches.

关键词： Bayesian inference model parameterization Shuttleworth-Wallace model

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FORCAsT-gs: Importance of Stomatal Conductance parameterization to Estimated Ozone Deposition Velocity

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JOURNAL OF ADVANCES IN modelING EARTH SYSTEMS 2021年第9期13卷 e2021MS002581-e2021MS002581页

作者： Otu-Larbi, Frederick Conte, Adriano Fares, Silvano Wild, Oliver Ashworth, Kirsti Lancaste Univ Lancaster Environm Ctr Lancaster England Council Agr Res & Econ CREA Res Ctr Forestry & Wood Arezzo Italy Natl Res Council Italy Inst BioEcon Rome Italy

The role of stomata in regulating photosynthesis and transpiration, and hence governing global biogeochemical cycles and climate, is well-known. Less well-understood, however, is the importance of stomatal control to the exchange of other trace gases between terrestrial vegetation and the atmosphere. Yet these gases determine atmospheric composition, and hence air quality and climate, on scales ranging from local to global, and seconds to decades. Vegetation is a major sink for ground-level ozone via the process of dry deposition and the primary source of many biogenic volatile organic compounds (BVOCs). The rate of dry deposition is largely controlled by the rate of diffusion of a gas through the stomata, and this also governs the emission rate of some key BVOCs. It is critical therefore that canopy-atmosphere exchange models capture the physiological processes controlling stomatal conductance and the transfer of trace gases other than carbon dioxide and water vapor. We incorporate three of the most widely used coupled stomatal conductance-photosynthesis models into the one-dimensional multi-layer FORest Canopy-Atmosphere Transfer (FORCAsT1.0) model to assess the importance of choice of parameterization on simulated ozone deposition rates. modeled GPP and stomatal conductance across a broad range of ecosystems differ by up to a factor of two between the best and worst performing model configurations. This leads to divergences in seasonal and diel profiles of ozone deposition velocity of up to 30% and deposition rate of up to 13%, demonstrating that the choice of stomatal conductance parameterization is critical in accurate quantification of ozone deposition.

关键词： ozone deposition Stomatal conductance gross primary productivity model parameterization ozone damage forest ecosystems

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Factors Affecting Entrainment Rate in Deep Convective Clouds and parameterizations

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2021年第15期126卷 e2021JD034881-e2021JD034881页

作者： Xu, Xiaoqi Sun, Cheng Lu, Chunsong Liu, Yangang Zhang, Guang Jun Chen, Qian Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Key Lab Aerosol Cloud Precipitat China Meteorol A Nanjing Peoples R China Taizhou Environm Monitoring Ctr Taizhou Peoples R China Brookhaven Natl Lab Environm & Climate Sci Dept Upton NY 11973 USA Univ Calif San Diego Scripps Inst Oceanog La Jolla CA 92093 USA

The parameterization of cloud entrainment rate has been problematic for many years, hindering the accurate representation of convective processes in large-scale models. Here, we extend our previous work on individual shallow convection to ensemble deep convection. Entrainment rate is estimated based on three-dimensional convective clouds from August 19 to 20, 1999, during the Kwajalein Experiment, simulated using a high-resolution cloud-resolving model. They are found to be negatively correlated with both vertical velocity and buoyancy, and positively correlated with the vertical divergence of the vertical velocity and with the reciprocal of cloud radii. The physical mechanisms underlying these relationships are interpreted. It is found that the parameterizations with multiple properties perform better than those with a single property. Entrainment rate and relative humidity of entrained air are positively correlated at temperature higher than 0 degrees C, but negatively correlated at temperature lower than 0 degrees C. Relative humidity is also included in the parameterization of entrainment rate, which differs from our previous work on shallow cumulus clouds and other studies. Finally, two forms of parameterization for entrainment rate are recommended. The first treats the entrainment rate as a function of the vertical velocity and buoyancy for temperature higher than 0 degrees C, but as a function of relative humidity and buoyancy for temperature lower than 0 degrees C. The second involves an equation that relates entrainment rate to vertical velocity and buoyancy regardless of temperature.

关键词： convective clouds entrainment rate model parameterization

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Towards Web3D-based Lightweight Crowd Evacuation Simulation 20

Towards Web3D-based Lightweight Crowd Evacuation Simulation

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25th ACM Conference on 3D Web Technology (Web3D)

作者： Piao, Xue Li, Yang Xie, Kang Zhao, Hantao Jia, Jinyuan Tongji Univ Sch Software Engn Shanghai Peoples R China Southeast Univ Sch Cyber Sci & Engn Nanjing Peoples R China Swiss Fed Inst Technol Chair Cognit Sci Zurich Switzerland

ISBN: (纸本)9781450381697

The heterogeneity of the appearance and behavior of the crowd is an important component in a realistic simulation. Using Web3D technology to recreate a large-scale crowd of virtual avatars via the internet is an increasingly important area in crowd studies, especially for emergency crowd evacuation. One major issue in the early development of real-time simulation is the challenge of introducing diversity and authenticity on avatars' appearance and behavior. Another major theoretical issue is high transmission delay on the network, which diminishes the simulation performed on the web browser when rendering a large number of visualization components. In this research, we propose a novel method to provide a lightweight solution that can simultaneously guarantee the realness and diversity of the simulated crowd. We use a parameterization technique based on shape space to distinguish the avatars' appearance. Asynchronously transmitting the rendering elements helps to reduce bandwidth pressure. The multi-level clone instancing method can generate a massive amount of heterogeneous avatars in a short time. In the end, we validated our methods with an online experiment to demonstrate its ability to solve large-scale crowd simulation problems over the internet.

关键词： web3D web browser crowd simulation evacuation behavior model parameterization avatar rendering

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