winter 2020 // stochastic processes and dynamical systems
Notes from Winter 2020 can be found here.
- Weeks 1-2: Poisson point processes
- Definition; Poisson limits; additivity; motivating examples.
- Thinning and labeling; conditional uniformity; characteristic functions and moments.
- Statistics of spatial point processes: testing for independence.
- Poisson jump processes.
- The Cauchy process.
- The Kolmogorov equation for pure-jump Levy processes.
- Weeks 3-4: Markov chains and generators
- Finite-state Markov chains: definitions, classificiation, transition probabilities.
- Methods for simulation: Poissonization.
- The approach to stationarity.
- Generators for Markov chains and Poisson jump processes.
- Uses and examples of generators.
- Simple random walk and relatives.
- Week 5: Brownian motion and Gaussian processes
- Brownian motion as a limit of simple random walk via convergence of the graph Laplacian.
- Brownian motion as an integral of white noise.
- Other integrals of white noise and the L2 isometry.
- Week 6: The stochastic integral
- Itô integration.
- Martingales and Itô integrals
- Itô’s lemma and stochastic calculus
- Weeks 7-8: Diffusions and associated PDE, via the Fokker-Planck equation
- Stochastic differential equations
- Backward Fokker-Planck equation from Itô’s lemma; connect to generators.
- Forward Fokker-Planck equation.
- Equilibrium distributions and approach to equilibrium.
- First passage times of diffusions.
- Detailed analysis of double-well potential example.
- Weeks 9-10: Linear systems theory
- Driven linear time-invariant systems LTI
- State-space vs. input/output views of LTI systems.
- Observability and controllability.
- Eigen-spectra, poles and zeros.
- Noise driven LTI systems (multi-dimensional Örnstein-Ulenbeck processes), steady-state autocorrelation and power spectral density.
- Application to nonlinear dynamical systems close to bifurcations.