Index Research Interests Academic Projects


  • Non-Linear Optimization
    • Gradient Based Algorithms
      • Sequential Unconstrained Minimization Technique (SUMT):
        Penalty Method, Log-Barrier Method, Augmented Lagrange Multipler (ALM) Method
      • Direct Method:
        Squential Quadratic Programming (SQP) -- Active-Set & Gradient-Projection
    • Zeroth-Order Evolutionary Algorithm
      Genetic Alogorithm
    • Maratos Effects
      Stagnation in optimization when steps give rise to a quadratic convergence rate but cause an increase both in the objective function value and the constraint norm.
    • Optimization and Mathemtical Programming Applications
      • Research Programs: SNOPT(Stanford), MMA(KTH)
      • Commercial Programs: LINGO-LINDO, MPL, Crystal Ball, Matlab Optimization Toolbox
  • Sensitivity Analysis and Numerical Gradient Calculation
    • Finite Difference (Forward- & Central-Step)
      Relative Finite Step Size
    • Complex Step
      Imaginary Step Size
    • Semi-Analytical Adjoint Sensitivity Calculation
      By using the adjoint sensitivity calculation, the computational cost for gradient of solver based function are obtained with only a single solution loop from solver.
  • Constraint Aggregation
    • Researched Methods
      • Maximum Constraint (MAX)
      • Kressielmeier-Steinhauser (KS) Function
      • Adaptive Kressielmeier-Steinhauser (AKS) Function
    • Compared performance of different constraint handling schemes
    • Studied the effect of using constraint aggregation in optimization process
    • Derived an adaptive approach to ensure the optimizer can access complete feasible region
    Wing Spar Structural Optimization Comparison