نتایج جستجو برای: Upscaling

تعداد نتایج: 1999  

Upscaling based on the bandwidth of the kernel function is a flexible approach to upscale the data because the cells will be coarse-based on variability. The intensity of the coarsening of cells in this method can be controlled with bandwidth. In a smooth variability region, a large number of cells will be merged, and vice versa, they will remain fine with severe variability. Bandwidth variatio...

2013
Masoud Babaei Ahmed H. Elsheikh Peter R. King

An adaptive quadtree grid generation algorithm is developed and applied for tracer and multiphase flow in channelized heterogeneous porous media. Adaptivity was guided using two different approaches. In the first approach, wavelet transformation was used to generate a refinement field based on permeability variations. The second approach uses flow information based on the solution of an initial...

Reservoir models with many grid blocks suffer from long run time; it is hence important to deliberate a method to remedy this drawback. Usual upscaling methods are proved to fail to reproduce fine grid model behaviors in coarse grid models in well proximity. This is attributed to rapid pressure changes in the near-well region. Standard permeability upscaling methods are limited to systems with ...

Journal: :Science signaling 2015
Jarrod P Meadows Mikael C Guzman-Karlsson Scott Phillips Cassie Holleman Jessica L Posey Jeremy J Day John J Hablitz J David Sweatt

Enhanced receptiveness at all synapses on a neuron that receive glutamatergic input is called cell-wide synaptic upscaling. We hypothesize that this type of synaptic plasticity may be critical for long-term memory storage within cortical circuits, a process that may also depend on epigenetic mechanisms, such as covalent chemical modification of DNA. We found that DNA cytosine demethylation medi...

2007
M. GERRITSEN J. V. LAMBERS

We propose a methodology, called multi-level local-global (MLLG) upscaling, for generating accurate upscaled models of permeabilities or transmissibilities for flow simulation on adapted grids in heterogeneous subsurface formations. The method generates an initial adapted grid based on the given fine-scale reservoir heterogeneity and potential flow paths. It then applies local-global (LG) upsca...

2012
Jingfeng Xiao Jiquan Chen Kenneth J. Davis Markus Reichstein

[1] Eddy covariance flux towers provide continuous measurements of ecosystem-level net exchange of carbon, water, energy, and other trace gases between land surface and the atmosphere. The upscaling of flux observations from towers to broad regions provides a new and independent approach for quantifying these fluxes over regions, continents, or the globe. The seven contributions of this special...

2015
Ming-fai Fong Jonathan P. Newman Steve M. Potter Peter Wenner

Homeostatic plasticity encompasses a set of mechanisms that are thought to stabilize firing rates in neural circuits. The most widely studied form of homeostatic plasticity is upward synaptic scaling (upscaling), characterized by a multiplicative increase in the strength of excitatory synaptic inputs to a neuron as a compensatory response to chronic reductions in firing rate. While reduced spik...

2003
Louis J. Durlofsky

A variety of approaches for the upscaling of detailed geocellular models for flow simulation are reviewed. Local, extended local, global and quasi global techniques for the calculation of equivalent permeability and transmissibility are discussed. Specialized procedures for permeability upscaling in the vicinity of wells are also described. Flow-based grid generation techniques, in which a curv...

Journal: :iranian journal of oil & gas science and technology 2014
seyed shamsollah noorbakhsh mohammad reza rasaei ali heydarian hamed behnaman

reservoir models with many grid blocks suffer from long run time; it is hence important to deliberatea method to remedy this drawback. usual upscaling methods are proved to fail to reproduce fine gridmodel behaviors in coarse grid models in well proximity. this is attributed to rapid pressure changesin the near-well region. standard permeability upscaling methods are limited to systems with lin...

2008
Alain Bourgeat Mladen Jurak

We present a robust and accurate strategy for upscaling two-phase flow in heterogeneous porous media composed of different rock-types. The method is tested by means of numerical simulations and compared with other upscaling methods.

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