In stochastic processes, chaos theory and time series analysis, detrended fluctuation analysis (DFA) is a method for determining the statistical self-affinity of a signal.
Sore throats caused by tonsillitis or streptococcus may trigger a canker sore even after the initial throat condition has subsided. Also known as an aphthous ulcer, canker sores are painful and unsightly, but they are not contagious.
Cold sores are caused by the herpes simplex type 1 virus and are contagious whereas canker sores are not. Also, cold sores can appear outside the mouth in places such as under the nose, on the lips or under the chin while canker sores always appear inside the mouth.