Some physical applications of the solution of ill-conditioned systems of linear equations

History of cosmic ray research in Finland

“…Such techniques were developed both in Turku and Oulu. These included studies of geometrical errors in directional intensities measured by counter telescopes, mathematical stabilization methods for unstable resolution corrections (Aurela and Torsti, 1967), atmospheric effect on ground-based flux of muons and neutrons (Tanskanen, 1968), scattering in cosmic ray muon spectrometers (Aurela and Torsti, 1968), a fast quadratic programming method for solving ill-conditioned systems of equations (Torsti and Aurela, 1972), and a special method to study solar neutrons by neutron monitors (Usoskin et al, 1997). For the interpretation of data obtained from the Turku hadron spectrometer, a comprehensive model of hadron cascades in the atmosphere and in the instrument was developed (Lumme et al, 1984).…”