Elastic alignment of numeric time series under Dynamic Time Warping with a Sakoe-Chiba band constraint, DTW Barycenter Averaging (DBA) for computing a prototype sequence from a set of variable-length observations, approximate medoid selection, linear resampling and robust dispersion estimation via the median absolute deviation. Pure Ruby, no dependencies. Pluggable local distance (Euclidean, Manhattan, Chebyshev, cosine) and central-tendency estimator (median, arithmetic mean).