Mary Wheeler - Academia.edu (original) (raw)

Papers by Mary Wheeler

Research paper thumbnail of Integrated time‐lapse seismic inversion for reservoir petrophysics and fluid‐flow imaging

SEG Technical Program Expanded Abstracts 2007, 2007

Research paper thumbnail of Part I. Improved Energy Estimates for Interior Penalty, Constrained and Discontinuous Galerkin Methods for Elliptic Problems

this paper, we discuss three numerical algorithms for elliptic problemswhich employ discontinuous... more this paper, we discuss three numerical algorithms for elliptic problemswhich employ discontinuous approximation spaces. The three methods are calledthe nonsymmetric interior penalty Galerkin method (NIPG), the nonsymmetricconstrained Galerkin (NCG) method, and the discontinuous Galerkin(DG)method. The three algorithms are closely related in that the underlying bilinearform for all three is the same and is nonsymmetric. Moreover, for all three methods,one can

Research paper thumbnail of Risk Factors for Recurrent Colonization With Methicillin-Resistant Staphylococcus aureus in Community-Dwelling Adults and Children

Infection control and hospital epidemiology, Jan 14, 2015

OBJECTIVE To identify risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRS... more OBJECTIVE To identify risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRSA) colonization. DESIGN Prospective cohort study conducted from January 1, 2010, through December 31, 2012. SETTING Five adult and pediatric academic medical centers. PARTICIPANTS Subjects (ie, index cases) who presented with acute community-onset MRSA skin and soft-tissue infection. METHODS Index cases and all household members performed self-sampling for MRSA colonization every 2 weeks for 6 months. Clearance of colonization was defined as 2 consecutive sampling periods with negative surveillance cultures. Recurrent colonization was defined as any positive MRSA surveillance culture after clearance. Index cases with recurrent MRSA colonization were compared with those without recurrence on the basis of antibiotic exposure, household demographic characteristics, and presence of MRSA colonization in household members. RESULTS The study cohort comprised 195 index cases; recurrent MRSA colo...

Research paper thumbnail of Binding in short-term visual memory

Journal of experimental psychology. General, 2002

The integration of complex information in working memory, and its effect on capacity, shape the l... more The integration of complex information in working memory, and its effect on capacity, shape the limits of conscious cognition. The literature conflicts on whether short-term visual memory represents information as integrated objects. A change-detection paradigm using objects defined by color with location or shape was used to investigate binding in short-term visual memory. Results showed that features from the same dimension compete for capacity, whereas features from different dimensions can be stored in parallel. Binding between these features can occur, but focused attention is required to create and maintain the binding over time, and this integrated format is vulnerable to interference. In the proposed model, working memory capacity is limited both by the independent capacity of simple feature stores and by demands on attention networks that integrate this distributed information into complex but unified thought objects.

Research paper thumbnail of Discontinuous Galerkin finite element methods for linear elasticity and quasistatic linear viscoelasticity

Research paper thumbnail of Duration of Colonization and Determinants of Earlier Clearance of Colonization with Methicillin-Resistant Staphylococcus aureus

Clinical Infectious Diseases, 2015

Research paper thumbnail of Mesh adaptation strategies for discontinuous Galerkin methods applied to reactive transport problems

Static and dynamic strategies are formulated and studied for discontinuous Galerkin (DG) methods ... more Static and dynamic strategies are formulated and studied for discontinuous Galerkin (DG) methods applied to reactive transport problems based on a posteriori error estimators. It is shown that the flexibility of DG allowing non-matching meshes substantially simplifies the implementation of the mesh adaptation. Moreover, DG with adaptivity can effectively capture local physical phenomena due to the localization of DG errors.

Research paper thumbnail of Coupling Different Numerical Algorithms for Two Phase Fluid Flow

The Mathematics of Finite Elements and Applications X, 2000

We discuss the coupling of dierent numerical algorithms for the solutionof two phase immiscible o... more We discuss the coupling of dierent numerical algorithms for the solutionof two phase immiscible ow problems. The computational domain for theow is split into several subdomains (blocks) on which dierent numericalalgorithms or models are implemented. We discuss in particular two algorithms:a fully implicit and a sequential formulation. Both are based on amixed nite element discretization in space and dier by

Research paper thumbnail of A Parallel Multiblock Black-Oil Model in Multimodel Implementation

SPE Journal, 2002

... In the part with gas cap, or with production wells around which free gas may be created becau... more ... In the part with gas cap, or with production wells around which free gas may be created because of low bottomhole pressure, a black-oil or a compositional code is necessary. ... It is governed by the equations Nw t = − Uw + qw, .... 16) No t = − Uo + qo. ...

Research paper thumbnail of A Parallel Multiblock/Multidomain Approach for Reservoir Simulation

SPE Reservoir Simulation Symposium, 1999

TX 75083-3836, U.S.A., fax 01-972-952-9435.

Research paper thumbnail of Iterative coupling reservoir simulation on high performance computers

Petroleum Science, 2009

In this paper, the iterative coupling approach is proposed for applications to solving multiphase... more In this paper, the iterative coupling approach is proposed for applications to solving multiphase flow equation systems in reservoir simulation, as it provides a more flexible time-stepping strategy than existing approaches. The iterative method decouples the whole equation systems into pressure and saturation/concentration equations, and then solves them in sequence, implicitly and semi-implicitly. At each time step, a series of iterations are computed, which involve solving linearized equations using specifi c tolerances that are iteration dependent. Following convergence of subproblems, material balance is checked. Convergence of time steps is based on material balance errors. Key components of the iterative method include phase scaling for deriving a pressure equation and use of several advanced numerical techniques. The iterative model is implemented for parallel computing platforms and shows high parallel effi ciency and scalability.

Research paper thumbnail of Driving Scientific Applications by Data in Distributed Environments

Lecture Notes in Computer Science, 2003

Traditional simulation-based applications for exploring a parameter space to understand a physica... more Traditional simulation-based applications for exploring a parameter space to understand a physical phenomenon or to optimize a design are rapidly overwhelmed by data volume when large numbers of simulations of different parameters are carried out. Optimizing reservoir management through simulation-based studies, in which large numbers of realizations are sought using detailed geologic descriptions, is an example of such applications. In

Research paper thumbnail of Towards Dynamic Data-Driven Management of the Ruby Gulch Waste Repository

Lecture Notes in Computer Science, 2006

Previous work in the Instrumented Oil-Field DDDAS project has enabled a new generation of data-dr... more Previous work in the Instrumented Oil-Field DDDAS project has enabled a new generation of data-driven, interactive and dynamically adaptive strategies for subsurface characterization and oil reservoir management. This work has led to the implementation of advanced multiphysics, multi-scale, and multi-block numerical models and an autonomic software stack for DDDAS applications. The stack implements a Gridbased adaptive execution engine, distributed data management services for real-time data access, exploration, and coupling, and self-managing middleware services for seamless discovery and composition of components, services, and data on the Grid. This paper investigates how these solutions can be leveraged and applied to address another DDDAS application of strategic importance -the data-driven management of Ruby Gulch Waste Repository.

Research paper thumbnail of Coupled Geomechanical and Reservoir Modeling on Parallel Computers

Proceedings of SPE Reservoir Simulation Symposium, 2003

Research paper thumbnail of Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling

The project objective was to detail better ways to assess and exploit intelligent oil and gas fie... more The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the ...

Research paper thumbnail of PCE-QUAL-ICM: A Parallel Water Quality Model Based on CE-QUAL-ICM

CE-QUAL-ICM is a three-dimensional eutrophication model developed at the U.S. Army Corps of Engin... more CE-QUAL-ICM is a three-dimensional eutrophication model developed at the U.S. Army Corps of EngineersWaterways Experiment Station (CEWES), Vicksburg, MS. This water quality model is semi-explicitin time, and is based on an unstructured cell-centered finite volume numerical method. The hydrodynamicsdata such as velocities and turbulent diffusion are read in externally, and the model computes the advectiondiffusion-reaction of a number of physical and state variables such as temperature,...

Research paper thumbnail of Accurate Cell-Centered Discretizations for Modeling Multiphase Flow in Porous Media on General Hexahedral and Simplicial Grids

Research paper thumbnail of A Multiscale Mortar Mixed Finite Element Method

Multiscale Modeling & Simulation, 2007

We develop multiscale mortar mixed finite element discretizations for second order elliptic equat... more We develop multiscale mortar mixed finite element discretizations for second order elliptic equations. The continuity of flux is imposed via a mortar finite element space on a coarse grid scale, while the equations in the coarse elements (or subdomains) are discretized on a fine grid scale. The polynomial degree of the mortar and subdomain approximation spaces may differ; in fact, the mortar space achieves approximation comparable to the fine scale on its coarse grid by using higher order polynomials. Our formulation is related to, but more flexible than, existing multiscale finite element and variational multiscale methods. We derive a priori error estimates and show, with appropriate choice of the mortar space, optimal order convergence and some superconvergence on the fine scale for both the solution and its flux. We also derive efficient and reliable a posteriori error estimators, which are used in an adaptive mesh refinement algorithm to obtain appropriate subdomain and mortar grids. Numerical experiments are presented in confirmation of the theory.

Research paper thumbnail of A Priori Error Estimates for Finite Element Methods Based on Discontinuous Approximation Spaces for Elliptic Problems

SIAM Journal on Numerical Analysis, 2001

Research paper thumbnail of Coupling Discontinuous Galerkin and Mixed Finite Element Discretizations using Mortar Finite Elements

SIAM Journal on Numerical Analysis, 2008

Discontinuous Galerkin (DG) and mixed finite element (MFE) methods are two popular methods that p... more Discontinuous Galerkin (DG) and mixed finite element (MFE) methods are two popular methods that possess local mass conservation. In this paper we investigate DG-DG and DG-MFE domain decomposition couplings using mortar finite elements to impose weak continuity of fluxes and pressures on the interface. The subdomain grids need not match, and the mortar grid may be much coarser, giving a two-scale method. Convergence results in terms of the fine subdomain scale h and the coarse mortar scale H are established for both types of couplings. In addition, a nonoverlapping parallel domain decomposition algorithm is developed, which reduces the coupled system to an interface mortar problem. The properties of the interface operator are analyzed.

Research paper thumbnail of Integrated time‐lapse seismic inversion for reservoir petrophysics and fluid‐flow imaging

SEG Technical Program Expanded Abstracts 2007, 2007

Research paper thumbnail of Part I. Improved Energy Estimates for Interior Penalty, Constrained and Discontinuous Galerkin Methods for Elliptic Problems

this paper, we discuss three numerical algorithms for elliptic problemswhich employ discontinuous... more this paper, we discuss three numerical algorithms for elliptic problemswhich employ discontinuous approximation spaces. The three methods are calledthe nonsymmetric interior penalty Galerkin method (NIPG), the nonsymmetricconstrained Galerkin (NCG) method, and the discontinuous Galerkin(DG)method. The three algorithms are closely related in that the underlying bilinearform for all three is the same and is nonsymmetric. Moreover, for all three methods,one can

Research paper thumbnail of Risk Factors for Recurrent Colonization With Methicillin-Resistant Staphylococcus aureus in Community-Dwelling Adults and Children

Infection control and hospital epidemiology, Jan 14, 2015

OBJECTIVE To identify risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRS... more OBJECTIVE To identify risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRSA) colonization. DESIGN Prospective cohort study conducted from January 1, 2010, through December 31, 2012. SETTING Five adult and pediatric academic medical centers. PARTICIPANTS Subjects (ie, index cases) who presented with acute community-onset MRSA skin and soft-tissue infection. METHODS Index cases and all household members performed self-sampling for MRSA colonization every 2 weeks for 6 months. Clearance of colonization was defined as 2 consecutive sampling periods with negative surveillance cultures. Recurrent colonization was defined as any positive MRSA surveillance culture after clearance. Index cases with recurrent MRSA colonization were compared with those without recurrence on the basis of antibiotic exposure, household demographic characteristics, and presence of MRSA colonization in household members. RESULTS The study cohort comprised 195 index cases; recurrent MRSA colo...

Research paper thumbnail of Binding in short-term visual memory

Journal of experimental psychology. General, 2002

The integration of complex information in working memory, and its effect on capacity, shape the l... more The integration of complex information in working memory, and its effect on capacity, shape the limits of conscious cognition. The literature conflicts on whether short-term visual memory represents information as integrated objects. A change-detection paradigm using objects defined by color with location or shape was used to investigate binding in short-term visual memory. Results showed that features from the same dimension compete for capacity, whereas features from different dimensions can be stored in parallel. Binding between these features can occur, but focused attention is required to create and maintain the binding over time, and this integrated format is vulnerable to interference. In the proposed model, working memory capacity is limited both by the independent capacity of simple feature stores and by demands on attention networks that integrate this distributed information into complex but unified thought objects.

Research paper thumbnail of Discontinuous Galerkin finite element methods for linear elasticity and quasistatic linear viscoelasticity

Research paper thumbnail of Duration of Colonization and Determinants of Earlier Clearance of Colonization with Methicillin-Resistant Staphylococcus aureus

Clinical Infectious Diseases, 2015

Research paper thumbnail of Mesh adaptation strategies for discontinuous Galerkin methods applied to reactive transport problems

Static and dynamic strategies are formulated and studied for discontinuous Galerkin (DG) methods ... more Static and dynamic strategies are formulated and studied for discontinuous Galerkin (DG) methods applied to reactive transport problems based on a posteriori error estimators. It is shown that the flexibility of DG allowing non-matching meshes substantially simplifies the implementation of the mesh adaptation. Moreover, DG with adaptivity can effectively capture local physical phenomena due to the localization of DG errors.

Research paper thumbnail of Coupling Different Numerical Algorithms for Two Phase Fluid Flow

The Mathematics of Finite Elements and Applications X, 2000

We discuss the coupling of dierent numerical algorithms for the solutionof two phase immiscible o... more We discuss the coupling of dierent numerical algorithms for the solutionof two phase immiscible ow problems. The computational domain for theow is split into several subdomains (blocks) on which dierent numericalalgorithms or models are implemented. We discuss in particular two algorithms:a fully implicit and a sequential formulation. Both are based on amixed nite element discretization in space and dier by

Research paper thumbnail of A Parallel Multiblock Black-Oil Model in Multimodel Implementation

SPE Journal, 2002

... In the part with gas cap, or with production wells around which free gas may be created becau... more ... In the part with gas cap, or with production wells around which free gas may be created because of low bottomhole pressure, a black-oil or a compositional code is necessary. ... It is governed by the equations Nw t = − Uw + qw, .... 16) No t = − Uo + qo. ...

Research paper thumbnail of A Parallel Multiblock/Multidomain Approach for Reservoir Simulation

SPE Reservoir Simulation Symposium, 1999

TX 75083-3836, U.S.A., fax 01-972-952-9435.

Research paper thumbnail of Iterative coupling reservoir simulation on high performance computers

Petroleum Science, 2009

In this paper, the iterative coupling approach is proposed for applications to solving multiphase... more In this paper, the iterative coupling approach is proposed for applications to solving multiphase flow equation systems in reservoir simulation, as it provides a more flexible time-stepping strategy than existing approaches. The iterative method decouples the whole equation systems into pressure and saturation/concentration equations, and then solves them in sequence, implicitly and semi-implicitly. At each time step, a series of iterations are computed, which involve solving linearized equations using specifi c tolerances that are iteration dependent. Following convergence of subproblems, material balance is checked. Convergence of time steps is based on material balance errors. Key components of the iterative method include phase scaling for deriving a pressure equation and use of several advanced numerical techniques. The iterative model is implemented for parallel computing platforms and shows high parallel effi ciency and scalability.

Research paper thumbnail of Driving Scientific Applications by Data in Distributed Environments

Lecture Notes in Computer Science, 2003

Traditional simulation-based applications for exploring a parameter space to understand a physica... more Traditional simulation-based applications for exploring a parameter space to understand a physical phenomenon or to optimize a design are rapidly overwhelmed by data volume when large numbers of simulations of different parameters are carried out. Optimizing reservoir management through simulation-based studies, in which large numbers of realizations are sought using detailed geologic descriptions, is an example of such applications. In

Research paper thumbnail of Towards Dynamic Data-Driven Management of the Ruby Gulch Waste Repository

Lecture Notes in Computer Science, 2006

Previous work in the Instrumented Oil-Field DDDAS project has enabled a new generation of data-dr... more Previous work in the Instrumented Oil-Field DDDAS project has enabled a new generation of data-driven, interactive and dynamically adaptive strategies for subsurface characterization and oil reservoir management. This work has led to the implementation of advanced multiphysics, multi-scale, and multi-block numerical models and an autonomic software stack for DDDAS applications. The stack implements a Gridbased adaptive execution engine, distributed data management services for real-time data access, exploration, and coupling, and self-managing middleware services for seamless discovery and composition of components, services, and data on the Grid. This paper investigates how these solutions can be leveraged and applied to address another DDDAS application of strategic importance -the data-driven management of Ruby Gulch Waste Repository.

Research paper thumbnail of Coupled Geomechanical and Reservoir Modeling on Parallel Computers

Proceedings of SPE Reservoir Simulation Symposium, 2003

Research paper thumbnail of Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling

The project objective was to detail better ways to assess and exploit intelligent oil and gas fie... more The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the ...

Research paper thumbnail of PCE-QUAL-ICM: A Parallel Water Quality Model Based on CE-QUAL-ICM

CE-QUAL-ICM is a three-dimensional eutrophication model developed at the U.S. Army Corps of Engin... more CE-QUAL-ICM is a three-dimensional eutrophication model developed at the U.S. Army Corps of EngineersWaterways Experiment Station (CEWES), Vicksburg, MS. This water quality model is semi-explicitin time, and is based on an unstructured cell-centered finite volume numerical method. The hydrodynamicsdata such as velocities and turbulent diffusion are read in externally, and the model computes the advectiondiffusion-reaction of a number of physical and state variables such as temperature,...

Research paper thumbnail of Accurate Cell-Centered Discretizations for Modeling Multiphase Flow in Porous Media on General Hexahedral and Simplicial Grids

Research paper thumbnail of A Multiscale Mortar Mixed Finite Element Method

Multiscale Modeling & Simulation, 2007

We develop multiscale mortar mixed finite element discretizations for second order elliptic equat... more We develop multiscale mortar mixed finite element discretizations for second order elliptic equations. The continuity of flux is imposed via a mortar finite element space on a coarse grid scale, while the equations in the coarse elements (or subdomains) are discretized on a fine grid scale. The polynomial degree of the mortar and subdomain approximation spaces may differ; in fact, the mortar space achieves approximation comparable to the fine scale on its coarse grid by using higher order polynomials. Our formulation is related to, but more flexible than, existing multiscale finite element and variational multiscale methods. We derive a priori error estimates and show, with appropriate choice of the mortar space, optimal order convergence and some superconvergence on the fine scale for both the solution and its flux. We also derive efficient and reliable a posteriori error estimators, which are used in an adaptive mesh refinement algorithm to obtain appropriate subdomain and mortar grids. Numerical experiments are presented in confirmation of the theory.

Research paper thumbnail of A Priori Error Estimates for Finite Element Methods Based on Discontinuous Approximation Spaces for Elliptic Problems

SIAM Journal on Numerical Analysis, 2001

Research paper thumbnail of Coupling Discontinuous Galerkin and Mixed Finite Element Discretizations using Mortar Finite Elements

SIAM Journal on Numerical Analysis, 2008

Discontinuous Galerkin (DG) and mixed finite element (MFE) methods are two popular methods that p... more Discontinuous Galerkin (DG) and mixed finite element (MFE) methods are two popular methods that possess local mass conservation. In this paper we investigate DG-DG and DG-MFE domain decomposition couplings using mortar finite elements to impose weak continuity of fluxes and pressures on the interface. The subdomain grids need not match, and the mortar grid may be much coarser, giving a two-scale method. Convergence results in terms of the fine subdomain scale h and the coarse mortar scale H are established for both types of couplings. In addition, a nonoverlapping parallel domain decomposition algorithm is developed, which reduces the coupled system to an interface mortar problem. The properties of the interface operator are analyzed.