The duality between estimation and control from a variational viewpoint: The discrete time case -- The conjugate process in stochastic realization theory -- A Hamiltonian approach to the factorization of the matrix Riccati equation -- On fast computation of superdiagonal Padé fractions -- Stochastic control in discrete time and applications to the theory of production -- Square-root information filtering and smoothing for precision orbit determination -- Some numerical aspects of multivariable systems identification -- Using the Hessenberg decomposition in control theory -- Algorithms for the design of control systems subject to singular value inequalities -- Collinear scaling and sequential estimation in sparse optimization algorithms.