Standard subspace algorithms learn Linear Dynamical Systems (LDSs) from time series with the least-square method, where the stability of the system is not naturally guaranteed. In this paper, we propose a novel approach for learning stable systems by enforcing stability directly on the leastsquare solutions. To this end, we first explore the spectral-radius property of the least-square transiti...

The relationship between the norm square of the standardized cumulative distribution and the chi-square statistic is examined using the form of the covariance matrix as well as the projection perspective. This investigation enables us to give uncorrelated components of the chi-square statistic and provide interpretation of these components as innovations standardizing the cumulative distributio...

Variable digital filters are useful for various signal processing and communication applications where the frequency characteristics, such as fractional delays and cutoff frequencies, can be varied. In this paper, we propose a design method of variable FIR digital filters with an approximate linear phase characteristic in the passband. The proposed variable FIR filters have some large attenuati...

Least squares method (LSM) is an accurate and rapid method for solving some analytical and numerical problems. This method can be used to estimate the average reservoir pressure in well test analysis. In fact, it may be employed to estimate parameters such as permeability (k) and pore volume (Vp). Regarding this point, buildup, drawdown, late transient test data, modified Muskat method, interfe...