Windsurfing aside, many expert windsurfers will ride the same waves as surfers do (wind permitting). At one time referred to as "surfing's ginger haired cousin" by the sport's legendary champion, Robby Naish, windsurfing has long struggled to present a coherent image of the sport to outsiders. As a result of attempts to claim the word "windsurfer" as a trademark, participants have been encouraged to use different names to describe the sport, including "sailboarding" and "boardsailing". The term "windsurfing" has persisted as the accepted name for the sport, and the word "windsurfer" persists for both participants and equipment. Windsurfing is predominately undertaken
Activity recognition models (HMM, CRF) for activity recognition can be found here. Conventional temporal probabilistic models such as the hidden Markov model (HMM) and conditional random fields (CRF) model directly model the correlations between the activities and the observed sensor data. In recent years, increasing evidence has supported the use of hierarchical models which take into account the rich hierarchical structure that exists in human behavioral data. The core idea here is that the model does not directly correlate the activities with the sensor data, but instead breaks the activity into sub-activities (sometimes referred to as actions) and models the underlying correlations