Results 61 to 70 of about 6,600 (212)

Machine Learning‐Driven Classification and Production Capacity Prediction of Tight Sandstone Reservoirs: A Case Study of the Taiyuan Formation, Ordos Basin

Energy Science &Engineering, EarlyView.
On the basis of core and log data, a Bayesian‐Optimized Random Forest model achieved 92.76% accuracy in classifying tight sandstone reservoirs. A gray relational analysis‐derived evaluation index shows > 80% consistency with actual gas zones. ABSTRACT Tight sandstone gas (TSG), an unconventional oil–gas resource, has heterogeneous reservoirs ...
Yin Yuan, Haijiao Fu, Detian Yan, Gang Wang, Shuguang Yang, Mengmeng Liu, Qingling Jiang, Xiaoming Wang, Wei Wang   +8 more
wiley   +1 more source

One-dimensional elliptic equation with concave and convex nonlinearities

Electronic Journal of Differential Equations, 2000
We establish the exact number of positive solutions for the boundary-value problem $$displaylines{ -(|u'|^{m-2} u')'=lambda u^q + u^pquad hbox{in }(0,1)cr u(0)= u(1)=0,, }$$ where $0leq q < m- 1 < p$ and $lambda$ is positive.
Justino Sanchez, Pedro Ubilla
doaj  

Local Polynomial Regression and Filtering for a Versatile Mesh‐Free PDE Solver

International Journal for Numerical Methods in Fluids, EarlyView.
A high‐order, mesh‐free finite difference method for solving differential equations is presented. Both derivative approximation and scheme stabilisation is carried out by parametric or non‐parametric local polynomial regression, making the resulting numerical method accurate, simple and versatile. Numerous numerical benchmark tests are investigated for
Alberto M. Gambaruto
wiley   +1 more source

Multiplicity of Solutions to a Potential Operator Equation and Its Applications

Abstract and Applied Analysis, 2014
We consider the multiplicity of solutions for operator equation involving homogeneous potential operators. With the help of Nehari manifold and fibering maps, we prove that such equation has at least two nontrivial solutions.
Jincheng Huang
doaj   +1 more source

Emerging single‐element ferroelectrics: From theory to experiment

InfoMat, EarlyView.
This review explores recent developments in single‐element ferroelectrics, covering mechanisms of ferroelectric behavior, their crystal structures, key preparation methods, ferroelectric performance characteristics, and promising device applications in field‐effect transistors, photodetectors, and visual perceptrons.
Run Zhao, Yuhang Zhang, Chen‐Min Dai, Fan Li, Jinlei Zhang, Ju Gao, Yucheng Jiang, Cheng‐Wei Qiu   +7 more
wiley   +1 more source

Bifurcation near infinity for the Neumann problem with concave–convex nonlinearities

Comptes Rendus. Mathématique, 2014
In this Note, we study a class of Neumann parametric elliptic equations driven by a nonhomogeneous differential operator and with a reaction that exhibits competing terms (concave–convex nonlinearities). Using the Ambrosetti–Rabinowitz condition and related topological and variational arguments, we prove a bifurcation result for large values of the ...
Papageorgiou, Nikolaos S., Rădulescu, Vicenţiu D.   +1 more
openaire   +2 more sources

Count Data Models With Heterogeneous Peer Effects Under Rational Expectations

Journal of Applied Econometrics, EarlyView.
ABSTRACT This paper develops a peer effect model for count responses under rational expectations. The model accounts for heterogeneity in peer effects across groups based on observed characteristics. Identification is based on the linear model condition that requires the presence of friends of friends who are not direct friends.
Aristide Houndetoungan
wiley   +1 more source

Some Positone Problems Suggested by Nonlinear Heat Generation [PDF]

, 1967
There is much current interest in boundary value problems containing positive linear differential operators and monotone functions of the dependent variable, see for example, M.A. Krasnosel'ski [1] and H. H. Schaefer [2]. We call such problems "positone"
Cohen, Donald S., Keller, Herbert B.
core  

Recursive Feasibility of Nonlinear Stochastic Model Predictive Control With Gaussian Process Dynamics

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Data‐based learning of system dynamics allows model‐based control approaches to be applied to systems with partially unknown dynamics. Gaussian process regression is a preferred approach that outputs not only the learned system model but also the variance of the model, which can be seen as a measure of uncertainty.
Daniel Landgraf, Andreas Völz, Knut Graichen   +2 more
wiley   +1 more source

Multiple Solutions for Nonlocal Fourth-Order Equation with Concave–Convex Nonlinearities

Mathematics
This paper is devoted to a class of general nonlocal fourth-order elliptic equation with concave–convex nonlinearities. First, using the Z2-mountain pass theorem in critical point theory, we obtain the existence of infinitely many large energy solutions.
Ruiting Jiang, Chengbo Zhai
doaj   +1 more source