Advanced Search
Displaying 21-30 on page 3 of 2285. Per Page  
  • Geophysical and Production Data History Matching Based on Ensemble Smoother with Multiple Data Assimilation
  • Abstract The Ensemble Kalman Filter (EnKF), as the most popular sequential data assimilation algorithm for history matching, has the intrinsic problem of high computational cost and the potential inconsistency of state variables updated at each loop of data assimilation and its corresponding reservoir simulated result. This problem forbids the reservoir engineers to make the best use of the 4D seismic data, which provides valuable information about the fluid change inside the reservoir. Moreover, only matching the production data in the past is not enough to accurately forecast the future, and the development plan based on the false forecast is very likely…
  • More
  •   Views:213       Downloads:168        Download PDF
  • Extracting Sub-Networks from Brain Functional Network Using Graph Regularized Nonnegative Matrix Factorization
  • Abstract Currently, functional connectomes constructed from neuroimaging data have emerged as a powerful tool in identifying brain disorders. If one brain disease just manifests as some cognitive dysfunction, it means that the disease may affect some local connectivity in the brain functional network. That is, there are functional abnormalities in the sub-network. Therefore, it is crucial to accurately identify them in pathological diagnosis. To solve these problems, we proposed a sub-network extraction method based on graph regularization nonnegative matrix factorization (GNMF). The dynamic functional networks of normal subjects and early mild cognitive impairment (eMCI) subjects were vectorized and the functional connection…
  • More
  •   Views:189       Downloads:164        Download PDF
  • T-Splines for Isogeometric Analysis of Two-Dimensional Nonlinear Problems
  • Abstract Nonlinear behaviors are commonplace in many complex engineering applications, e.g., metal forming, vehicle crash test and so on. This paper focuses on the T-spline based isogeometric analysis of two-dimensional nonlinear problems including general large deformation hyperelastic problems and small deformation elastoplastic problems, to reveal the advantages of local refinement property of T-splines in describing nonlinear behavior of materials. By applying the adaptive refinement capability of T-splines during the iteration process of analysis, the numerical simulation accuracy of the nonlinear model could be increased dramatically. The Bézier extraction of the T-splines provides an element structure for isogeometric analysis that can be…
  • More
  •   Views:217       Downloads:174        Download PDF
  • RBF-FD Method for Some Dispersive Wave Equations and Their Eventual Periodicity
  • Abstract In this paper, we approximate the solution and also discuss the periodic behavior termed as eventual periodicity of solutions of (IBVPs) for some dispersive wave equations on a bounded domain corresponding to periodic forcing. The constructed numerical scheme is based on radial kernels and local in nature like finite difference method. The temporal variable is executed through RK4 scheme. Due to the local nature and sparse differentiation matrices our numerical scheme efficiently recovers the solution. The results achieved are validated and examined with other methods accessible in the literature.
  • More
  •   Views:164       Downloads:147        Download PDF
  • A Discrete Model of TB Dynamics in Khyber Pakhtunkhwa-Pakistan
  • Abstract The present paper investigates the theoretical analysis of the tuberculosis (TB) model in the discrete-time case. The model is parameterized by the TB infection cases in the Pakistani province of Khyber Pakhtunkhwa between 2002 and 2017. The model is parameterized and the basic reproduction number is obtained and it is found R0 ¼ 1:5853. The stability analysis for the model is presented and it is shown that the discrete-time tuberculosis model is stable at the disease-free equilibrium whenever R0 < 1 and further we establish the results for the endemic equilibria and prove that the model is globally asymptotically stable…
  • More
  •   Views:209       Downloads:149        Download PDF
  • An ADI Finite Volume Element Method for a Viscous Wave Equation with Variable Coefficients
  • Abstract Based on rectangular partition and bilinear interpolation, we construct an alternating-direction implicit (ADI) finite volume element method, which combined the merits of finite volume element method and alternating direction implicit method to solve a viscous wave equation with variable coefficients. This paper presents a general procedure to construct the alternating-direction implicit finite volume element method and gives computational schemes. Optimal error estimate in L2 norm is obtained for the schemes. Compared with the finite volume element method of the same convergence order, our method is more effective in terms of running time with the increasing of the computing scale. Numerical…
  • More
  •   Views:196       Downloads:164        Download PDF
  • Identification of the Discrete Element Model Parameters for Rock-Like Brittle Materials
  • Abstract An inverse method for parameters identification of discrete element model combined with experiment is proposed. The inverse problem of parameter identification is transmitted to solve an optimization problem by minimizing the distance between the numerical calculations and experiment responses. In this method, the discrete element method is employed as numerical calculator for the forward problem. Then, the orthogonal experiment design with range analysis was used to carry out parameters sensitivity analysis. In addition, to improve the computational efficiency, the approximate model technique is used to replace the actual computational model. The intergeneration projection genetic algorithm (IP-GA) is employed as the…
  • More
  •   Views:188       Downloads:163        Download PDF
  • Collapse Simulation and Response Assessment of a Large Cooling Tower Subjected to Strong Earthquake Ground Motions
  • Abstract Large cooling towers in thermal power plants and nuclear power plants are likely to suffer from strong earthquakes during service periods. The resulting destructions of the cooling towers would endanger the power plants and threaten the security of the related areas. It is important to use effective means to evaluate the safety status of the cooling towers and guide further precautions as well as retrofitting efforts. This paper is therefore focused on an elaborate numerical investigation to the earthquake-induced collapses of a large cooling tower structure. A complete numerical work for simulation of material failure, component fracture, structural buckling and…
  • More
  •   Views:212       Downloads:194        Download PDF
  • Comparison between the Seismic Performance of Buried Pipes and Pipes in a Utility Tunnel
  • Abstract A utility tunnel system consists of pipes and ancillary facilities. In this paper, a finite element model of a concrete utility tunnel with pipes inside is established. Several tunnel segments were built to simulate a real utility tunnel, while the pipe was fixed by springs on the brackets in the utility tunnel. Using the discrete soil spring element to simulate the soil-structure interaction, actual earthquake records were adopted as excitation to analyze the seismic responses of pipes in a utility tunnel. Moreover, the influences of different parameters, including soil type, earthquake records, and field apparent wave velocity on the seismic…
  • More
  •   Views:189       Downloads:183        Download PDF
  • Building Information Modeling-Based Secondary Development System for 3D Modeling of Underground Pipelines
  • Abstract Underground pipeline networks constitute a major component of urban infrastructure, and thus, it is imperative to have an efficient mechanism to manage them. This study introduces a secondary development system to efficiently model underground pipeline networks, using the building information modeling (BIM)-based software Revit. The system comprises separate pipe point and tubulation models. Using a Revit application programming interface (API), the spatial position and attribute data of the pipe points are extracted from a pipeline database, and the corresponding tubulation data are extracted from a tubulation database. Using the Family class in Revit API, the cluster in the self-built library…
  • More
  •   Views:227       Downloads:182        Download PDF
Displaying 21-30 on page 3 of 2285. Per Page