Spire Global
Global Validation Model Department
Boulder CO 80302, USA

E-mail:
rstefane@vt.edu

Razvan Stefanescu

May 8, 1981





  • My Google Scholar citation page

  • Research Interests

    • Numerical Optimization
    • Machine Learning
    • Data Assimilation
    • Numerical methods for inverse problems, PDE - constrained optimization, reduced order optimization methods
    • Adjoint-based space-time adaptive solution algorithms for sensitivity analysis and inverse problems
    • Numerical methods (theory, algorithms and computer programs) for optimal control problems governed by PDEs and by variational inequalities
    • Bayesian methods and uncertainty quantification
    • Optimal design of experiments for nonlinear inverse problems
    • Numerical optimization

    • Local methods
    • Global methods
    • Non-smooth and derivative free methods
    • Linear and non-linear programming
    • Machine Learning

    • Ridge, Lasso, Least Angle regression
    • Linear Discriminant Analysis, Logistic Regression, Support Vector Machine
    • Feature selection methods: Best-Subset Selection, Forward and Backward-Stepwise Selection
    • Gaussian Process
    • Neural Networks
    • Data Assimilation

    • Variational (adjoint based), ensemble and hybrid based Data Assimilation techniques
    • Data Assimilation using WRF, MPAS, GSI, WRFDA
    • Impact of observation and model errors to various quantity of interest

      Bayesian Methods and Uncertainty Quantification

    • Markov Chain Monte Carlo
    • Hamiltonian Monte Carlo
    • Delayed Rejection Adaptive Metropolis
    • Differential Evolution Adaptive Metropolis
    • Reduced Order Modelling

    • Projection Based Reduced-Order Modelling
    • Proper Orthogonal Decomposition
    • Discrete Emperical Interpolation Method (DEIM)
    • Gappy POD
    • Missing Point Estimation
    • Applied mathematics

    • Fluid dynamics
    • Atmospheric and numerical weather prediction models
    • Nuclear nonproliferation
    • Population dynamics
    • Immunological models
    • Portfolio optimization and factor models


    Publications / Scholar Activities

    Articles in Conference proceedings, Journals and Magazines

    Academic Background

    2005 - 2010 (January, 29), Faculty of Mathematics, Al. I. Cuza University, Iasi, Romania
    Ph.D., thesis: Numerical Algorithms for the Approximation of Elliptic PDEs and Applications

    2003 - 2005, Faculty of Mathematics, Al. I. Cuza University, Iasi, Romania
    M.Sc. in Mathematical Modeling, dissertation: Applications in Financial Mathematics using Black - Scholes equation

    1999 - 2003, Faculty of Mathematics, Al. I. Cuza University, Iasi, Romania
    B.Sc., thesis: Object-Oriented Programming Applications, A Linear Algebraic Library

    Work Experience

    August 2015 - Now - Postdoctoral Scholar, North Carolina State University, Department of Mathematics, Raleigh, North Carolina, USA
    National Nuclear Security Administration (USA) grant supporting the Consortium for Nonproliferation Enabling Capabilities.

    July 2013 - August 2015 - Postdoctoral Scholar, Virginia Tech, Department of Computer Science, Blacksburg, Virginia, USA
    National Science Foundation project: A Fully Discrete Framework for the Adaptive Solution of Inverse Problems

    February 2011 - June 2013 - Postdoctoral Scholar, Florida State Universiy, Department of Scientific Computing, Florida, USA
    National Oceanic and Atmospheric Administration project: Data Assimilation of lightning in WRF-4D VAR using nonlinear observation operators

    May 2009 - February 2011, Assistant Researcher, Faculty of Automatic Control and Computers, Gh. Asachi Technical University, Iasi, Romania

    October 2007-March 2009 - Assistant Researcher, Faculty of Mathematics, Al. I. Cuza University, Iasi, Romania

    Teaching:
    July 2013 - August 2015 - Researcher Associate, Numerical Optimization Classes, Department of Computer Science, Virginia Tech, Blacksburg, Virginia, USA

    January 2011 - June 2013 - Postdoctoral Scholar, Data Assimilation, Optimization and Preconditioning Methods Classes, Department of Scientific Computing, Florida State University, Tallahassee, Florida, USA

    March 2008 - February 2011 - Assistant Professor, Statistics and Computer Science Classes, Faculty of Pharmacy, Department of Mathematics and Scientific Computing, Universiy of Medicine and Pharmacy Gr. T. Popa, Iasi, Romania

    October 2006 - June 2007 - Teaching Assistant, Object-Oriented Programming Classes in C++, Faculty of Mathematics, Al. I. Cuza University, Iasi, Romania

    Honors

    • 2011 - Who's Who in the World (28th Edition)

    Applications and resources developed

    • 4D-Var Data Assimilation of lightning observation using incremental WRFDA
    • 1D+4DVar Data Assimilation of lightning observation using incremental WRFDA

    Languages

    Romanian (native), English (fluent), French (some)

    Experience in Research Programs

    • August 2015 - now, member of National Nuclear Security Administration (USA) grant supporting the Consortium for Nonproliferation Enabling Capabilities
    • July 2013 - August 2015, member of National Science Foundation project, A Fully Discrete Framework for the Adaptive Solution of Inverse Problems
    • 2011 - June 2013, member of National Oceanic and Atmospheric Administration project, Data Assimilation of lightning in WRF-4D VAR using nonlinear observation operators
    • 2009 - 2011, 2009 - 2011 , member of IDEI project, No. 342/2009, CNCSIS, Nonlinear Evolution Equation, Theoretical Aspects and Applications to Life and Environmental Sciences
    • 2007 - 2008, director of TD project, 201 no. 569/2007, CNCSIS, Numerical Algorithms for the Approximation of Elliptic PDE and Applications.

    International Conference Talks

    Courses Attended

    • Basic WRF Tutorial, 11 - 15 July 2011, NCAR Foothills Laboratory, Boulder, Colorado, Usa.
    • WRF DA Tutorial, 20-22 July 2011, NCAR Foothills Laboratory, Boulder, Colorado, Usa.