Using structural frames to integrate structural geology into implicit 3D modelling

2020 ◽  
Author(s):  
Lachlan Grose ◽  
Gautier Laurent ◽  
Laurent Ailleres
Keyword(s):  
Structural Geology ◽  
Conceptual Model ◽  
Model Parameters ◽  
Fold Axis ◽  
Fault Surface ◽  
Subjective Interpretation ◽  
3D Geometry ◽  
Structural Frame ◽  
Recent Developments ◽  
Structural Frames

<p>Implicit geological modelling allows for observations of surface location and orientation to be interpolated into continuous 3D surfaces. These surfaces are usually built by finding a function that minimises the misfit between the surface and observations (gradient or value of the implicit function) combined with a regularisation constraint that controls how the surface develops between observations. When modelling complex terranes such as fold series, fault networks or intrusions it is usually necessary to use interpretive constraints for creating the expected geometries. These interpretations are problematic, as the constraints are usually not observations but realisations of the geologists’ subjective interpretation, and are therefore difficult to change and interrogate to better understand the geometry. Recent developments for implicit modelling of folds and faults have built new local coordinate systems using the structural geology of the object being modelled and are termed structural frames. For example, for folds, the structural frame is aligned to the axial surface of the fold and fold axis. For faults, the structural frame is aligned to the fault surface and slip direction. Using structural frames, conceptual models of the fold and fault geometries can be combined with the observations of the surfaces. This means that rather than using the geologists' subjective interpretation to constrain the model geometries, the conceptual model can guide the interpolation where observations are missing. Geological uncertainties in the resulting geometries can be assessed by framing the modelling as an inverse problem and varying the conceptual model parameters to fit the geological observations. In this contribution, we review the use of structural frames for constraining 3D geometry of structurally complex terranes and provide an example of a faulted fold series.</p>

On the astronomical forcing of simple conceptual ice age models

2020 ◽  
Author(s):  
Gaëlle Leloup ◽  
Didier Paillard
Keyword(s):  
Conceptual Model ◽  
Climate Model ◽  
Ice Age ◽  
Early Pleistocene ◽  
Model Parameters ◽  
Ice Ages ◽  
Glacial Cycles ◽  
Orbital Parameters ◽  
Ice Volume ◽  
Astronomical Forcing

<p>Variations of the Earth’s orbital parameters are known to pace the ice volume variations of the last million year [1], even if the precise mechanisms remain unknown.<br>Several conceptual models have been used to try to better understand the connection between ice-sheet changes and the astronomical forcing. An often overlooked question is to decide which astronomical forcing can best explain the observed cycles.</p><p>A rather traditional practice was to use the insolation at a some specific day of the year, for instance at mid-july [2] or at the june solstice [3].<br>But it was also suggested that the integrated forcing above some given threshold could be a better alternative [4]. In a more recent paper, Tzedakis et al. [5] have shown that simple rules, based on the original Milankovitch forcing or caloric seasons, could also be used to explain the timing of ice ages.<br>Here we adapt and simplify the conceptual model of Parrenin and Paillard 2003 [6], to first reduce the set of parameters.<br>Like in the original conceptual model from [6], this simplified conceptual model is based on climate oscillations between two states: glaciation and deglaciation. It switches to one another when crossing a defined threshold. While the triggering of glaciations is only triggered by orbital parameters, the triggering of deglaciations is triggered by a combination of orbital parameters and ice volume. <br>Then, we apply the different possible forcings listed above and we try to adapt the model parameters to reproduce the ice volume record, at least in a qualitative way. This allows us to discuss which kind of astronomical forcing better explains the Quaternary ice ages, in the context of such simple threshold-based models.</p><p>[1] Variations in the Earth's Orbit: Pacemaker of the Ice Ages, Hays et al., 1976, Science
</p><p>[2] Modeling the Climatic Response to Orbital Variations, Imbrie and Imbrie, 1980, Science
</p><p>[3] The timing of Pleistocene glaciations from a simple multiple-state climate model, Paillard, 1998, Nature</p><p>[4] Early Pleistocene Glacial Cycles and the Integrated Summer Insolation Forcing, Huybers et al., 2006, Science</p><p>[5] A simple rule to determine which insolation cycles lead to interglacials, Tzedakis et al., 2017, Nature</p><p>[6] Amplitude and phase of glacial cycles from a conceptual model, Parrenin Paillard, 2003, EPSL.</p>

scholarly journals Co-Production in Business Counselling in Microfinance Setting: A Conceptual Approach

2015 ◽  
Vol 23 (03) ◽  
pp. 299-319 ◽  
Author(s):  
Ruwan Abeysekera ◽  
Dean Patton ◽  
Andrew Mullineux
Keyword(s):  
Conceptual Model ◽  
Empirical Studies ◽  
Small Enterprises ◽  
Microfinance Institutions ◽  
Conceptual Approach ◽  
Dyadic Relationship ◽  
Policy Makers ◽  
Recent Developments ◽  
Micro And Small Enterprises ◽  
Literature Highlight

Recent developments in service literature highlight the importance of co-production between the firm and the client in order to create value. This paper presents a model of co-production within the context of microfinance provision and investigates the dyadic relationship between Counsellors from Microfinance Institutions (MFIs) and the Owner Managers of Micro and Small Enterprises (MSEs). The paper develops a conceptual model that identifies the factors that facilitate co-production between Counsellors and Owner Managers. It also identifies co-production outcomes relating to MSEs and MFIs concerned. The model offers researchers a framework for empirical studies in the microfinance setting. Furthermore, microfinance policy makers can use this model to formulate strategies that offer many benefits to both MFIs and Owner Managers.

scholarly journals Time-domain determination of earthquake fault parameters from short-period P-waves

1976 ◽  
Vol 66 (5) ◽  
pp. 1459-1484
Author(s):  
Paul G. Somerville ◽  
Ralph A. Wiggins ◽  
Robert M. Ellis
Keyword(s):  
Time Domain ◽  
Time Function ◽  
Wave Radiation ◽  
Model Parameters ◽  
Half Cycle ◽  
Rupture Velocity ◽  
Fault Surface ◽  
Fault Parameters ◽  
Short Period

abstract Source parameters of two shallow earthquakes have been determined by the time-domain analysis of short-period teleseismic recordings. For each event, the effect of the receiver crust was deconvolved from a set of globally distributed recordings using the homomorphic method. The resulting seismograms were compared with the form of the elastic-wave radiation computed from Savage's model of radially spreading rupture on a plane elliptical fault surface. This time-domain approach has permitted the determination of several kinematic parameters pertaining to the dynamics of rupture that are not ordinarily evaluated from spectral analysis. These parameters are rupture velocity, the direction of farthest rupture propagation, and the duration of a ramp dislocation time function which was prescribed to be the same everywhere on the fault surface. The application of a general linear inverse scheme has shown that the model parameters (notably rupture velocity and dimension) are only weakly coupled. Inversion is also used to determine the range of acceptable parameter values and indicates the importance of array recordings in constraining the models. A consistent discrepancy between the observed and model seismograms during the first half-cycle of motion is attributed to the incorrect prescription of the dislocation time function. It is suggested that a space-dependent function determined theoretically by Kostrov in 1964 would tend to remove this discrepancy.

scholarly journals Bayesian differential programming for robust systems identification under uncertainty

2020 ◽  
Vol 476 (2243) ◽  
pp. 20200290
Author(s):  
Yibo Yang ◽  
Mohamed Aziz Bhouri ◽  
Paris Perdikaris
Keyword(s):  
Nonlinear Dynamical Systems ◽  
Monte Carlo Sampling ◽  
Model Parameters ◽  
Nonlinear Dynamical ◽  
Predator Prey ◽  
Learning Framework ◽  
Numerical Studies ◽  
Recent Developments ◽  
Systems Identification ◽  
Robust Systems

This paper presents a machine learning framework for Bayesian systems identification from noisy, sparse and irregular observations of nonlinear dynamical systems. The proposed method takes advantage of recent developments in differentiable programming to propagate gradient information through ordinary differential equation solvers and perform Bayesian inference with respect to unknown model parameters using Hamiltonian Monte Carlo sampling. This allows an efficient inference of the posterior distributions over plausible models with quantified uncertainty, while the use of sparsity-promoting priors enables the discovery of interpretable and parsimonious representations for the underlying latent dynamics. A series of numerical studies is presented to demonstrate the effectiveness of the proposed methods, including nonlinear oscillators, predator–prey systems and examples from systems biology. Taken together, our findings put forth a flexible and robust workflow for data-driven model discovery under uncertainty. All codes and data accompanying this article are available at https://bit.ly/34FOJMj .

scholarly journals Identifying Vehicle Model Parameters Using Remote Mounted Motion Sensor

2021 ◽  
Author(s):  
Yoonjin Hwang
Keyword(s):  
Vehicle Dynamics ◽  
Model Parameters ◽  
Motion Sensor ◽  
Force Model ◽  
Single Track ◽  
Driver Assistance ◽  
Vehicle Model ◽  
Tire Force ◽  
Recent Developments ◽  
Potential Benefits

The recent developments on advanced driver assistance system(ADAS) have extended the capability of sensor systems from surrounding perception to motion estimation. The motion estima?tion provides tri-axial velocity and pose measurements, which open potential benefits for control and state estimation through sensor fusion with the vehicle dynamics model. In this paper we propose an identification method for the vehicle single track model parameters including the relative distance between the vehicle center of gravity and the motion sensor. A linearized tire force model and simplified single track vehicle model are constructed with the corresponding sensor kinematics model. We demonstrate the efficacy of iden?tification performance of the proposed method and confirm the feasibility of the usage of ADAS sensor in vehicle dynamics and vice versa

scholarly journals A framework to regionalize conceptual model parameters for global hydrological modeling

2020 ◽  
Author(s):  
Wenyan Qi ◽  
Jie Chen ◽  
Lu Li ◽  
Chong-yu Xu ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Water Resources ◽  
Conceptual Model ◽  
Hydrological Modeling ◽  
Global Scale ◽  
Spatial Proximity ◽  
Model Parameters ◽  
Hydrological Models ◽  
Physical Similarity ◽  
Similarity Method ◽  
Global Water

Abstract. To provide an accurate estimate of global water resources and help to formulate water allocation policies, global hydrological models (GHMs) have been developed. However, it is difficult to obtain parameter values for GHMs, which results in large uncertainty in estimation of the global water balance components. In this study, a framework is developed for building GHMs based on parameter regionalization of catchment scale conceptual hydrological models. That is, using appropriate global scale regionalization scheme (GSRS) and conceptual hydrological models to simulate runoff at the grid scale globally and the Network Response Routing (NRF) method to converge the grid runoff to catchment streamflow. To achieve this, five regionalization methods (i.e. the global mean method, the spatial proximity method, the physical similarity method, the physical similarity method considering distance, and the regression method) are first tested for four conceptual hydrological models over thousands medium-sized catchments (2500–50000 km2) around the world to find the appropriate global scale regionalization scheme. The selected GSRS is then used to regionalize conceptual model parameters for global land grids with 0.5°×0.5° resolution on latitude and longitude. The results show that: (1) Spatial proximity method with the Inverse Distance Weighting (IDW) method and the output average option (SPI-OUT) offers the best regionalization solution, and the greatest gains of the SPI-OUT method were achieved with mean distance between the donor catchments and the target catchment is no more than 1500 km. (2) It was found the Kling-Gupta efficiency (KGE) value of 0.5 is a good threshold value to select donor catchments. And (3) Four different GHMs established based on framework were able to produce reliable streamflow simulations. Overall, the proposal framework can be used with any conceptual hydrological model for estimating global water resources, even though uncertainty exists in terms of using difference conceptual models.

scholarly journals OPPORTUNITIES FOR INTERACTIVE, PHYSICS-DRIVEN WAVE SIMULATION USING THE BOUSSINESQ-TYPE MODEL, CELERIS

2017 ◽  
pp. 11
Author(s):  
Sasan Tavakkol ◽  
Patrick Lynett
Keyword(s):  
Boundary Conditions ◽  
Wave Model ◽  
Simulation Software ◽  
Irregular Waves ◽  
Type Model ◽  
Model Parameters ◽  
Breaking Wave ◽  
Wave Simulation ◽  
Recent Developments ◽  
Language Environment

In this paper, we discuss the recent developments of our GPU-based Boussinesq-type wave simulation software, Celeris. This software is meant to serve the primary purpose of being interactive – i.e. allowing the user to modify the boundary conditions and model parameters as the model is running, and to see the effect of these changes immediately. To accomplish this, the model is coded in a shader language environment, and our physical variables (e.g. ocean surface elevation, water velocity) are represented in the model as graphical textures, which can therefore be rapidly rendered and visualized via a GPU. The model may run faster than real-time for problems with practical setups. Following a description of the numerical development of the wave model, we elaborate on the recent features that are added to the software such as irregular waves and uniform time series boundary conditions. Since the model is previously validated for breaking and non-breaking wave, in this paper, we compare the numerical results of the model with experimental results of a current benchmark and show its good agreement.

scholarly journals Sensitivity and Interdependency Analysis of the HBV Conceptual Model Parameters in a Semi-Arid Mountainous Watershed

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2440
Author(s):  
Hamza Ouatiki ◽  
Abdelghani Boudhar ◽  
Aziz Ouhinou ◽  
Abdelaziz Beljadid ◽  
Marc Leblanc ◽  
...  
Keyword(s):  
Snow Cover ◽  
Conceptual Model ◽  
Water Resource Management ◽  
Optimal Parameter ◽  
Field Capacity ◽  
Temperature Correction ◽  
Model Parameters ◽  
Daily Streamflow ◽  
Model Response ◽  
Semi Arid

Hydrological models, with different levels of complexity, have become inherent tools in water resource management. Conceptual models with low input data requirements are preferred for streamflow modeling, particularly in poorly gauged watersheds. However, the inadequacy of model structures in the hydrologic regime of a given watershed can lead to uncertain parameter estimation. Therefore, an understanding of the model parameters’ behavior with respect to the dominant hydrologic responses is of high necessity. In this study, we aim to investigate the parameterization of the HBV (Hydrologiska Byråns Vattenbalansavedelning) conceptual model and its influence on the model response in a semi-arid context. To this end, the capability of the model to simulate the daily streamflow was evaluated. Then, sensitivity and interdependency analyses were carried out to identify the most influential model parameters and emphasize how these parameters interact to fit the observed streamflow under contrasted hydroclimatic conditions. The results show that the HBV model can fairly reproduce the observed daily streamflow in the watershed of interest. However, the reliability of the model simulations varies from one year to another. The sensitivity analysis showed that each of the model parameters has a certain degree of influence on model behavior. The temperature correction factor (ETF) showed the lowest effect on the model response, while the sensitivity to the degree-day factor (DDF) highly depends on the availability of snow cover. Overall, the changes in hydroclimatic conditions were found to be mostly responsible for the annual variability of the optimal parameter values. Additionally, these changes seem to actuate the interdependency between the parameters of the soil moisture and the response routines, particularly Field Capacity (FC), the recession coefficient K0, the percolation coefficient (KPERC), and the upper reservoir threshold (UZL). The latter combines either to shrink the storage capacity of the model’s reservoirs under extremely high peak flows or to enlarge them under overestimated water supply, mainly provoked by abundant snow cover.

The three-dimensional geometries of segmented normal faults

2020 ◽  
Author(s):  
John Walsh ◽  
Vincent Roche ◽  
Giovanni Camanni ◽  
Conrad Childs ◽  
Tom Manzocchi ◽  
...  
Keyword(s):  
Full Range ◽  
Three Dimensional ◽  
Normal Faults ◽  
Basement Structure ◽  
Mechanical Heterogeneity ◽  
Fault Surface ◽  
Mechanical Stratigraphy ◽  
Data Resolution ◽  
3D Geometry ◽  
Quantitative Basis

<p>Normal faults are often complex three dimensional structures comprising multiple sub-parallel segments separated by intervening relay zones. In this study we outline geometrical characterisations capturing this 3D complexity and providing a semi-quantitative basis for the comparison of faults and for defining the factors controlling their geometrical evolution.</p><p>Individual relay zones can be assigned to one of four types according to their form (i.e. whether the bounding segments are unconnected in 3D or merge into a single surface) and their orientation (i.e. whether they are slip-parallel or slip-perpendicular). From the detailed analysis of 84 fault arrays mapped from 3D seismic reflection surveys (including 63 from our mapping of 8 different study areas and 21 derived from the literature), we show that the 3D geometry of fault arrays can be quantitatively defined on the basis of the relative numbers of these types of relay zones.</p><p>Detailed mapping of fault zones indicates that whilst they can individually contain all four types of relay zone, their relative proportions varies between different study areas. Differences in the proportions of relay zone types are attributed to two primary controls, the mechanical heterogeneity of the faulted sequence and the presence of basement structure. For example, relay zones with an upward bifurcating geometry are prevalent in faults that reactivate deeper structures, whereas the formation of laterally bifurcating relays is promoted by heterogeneous mechanical stratigraphy. </p><p>Fault arrays in the literature generally do not contain the full range of possible relay zone type but tend to comprise either all bifurcating relay zones or all unconnected relay zones. These end-member fault geometries have led to contrasting conceptual models for the growth of faults. The mapping conducted here suggests that the proportion of bifurcating relay zones increases as data resolution increases and that fault surface bifurcation is ubiquitous. Models for the geometrical evolution of fault arrays must account for the full range of relay zone geometries that appears to be a characteristic of all faults.</p>

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