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Table 1 Summary of previous COACH systems.

From: The COACH prompting system to assist older adults with dementia through handwashing: An efficacy study

COACH Version Tracking System Decision-making system Prompting system Number of Subjects* Related Publications
Version 1 Pattern wristband worn by the user Neural networks interacting with a hard-coded taxonomy Audio prompts, with one prompt for each step 10 [22, 33]
Version 2 Using background subtraction to isolate the user's hands. Tracking of hands and task objects (i.e. soap and towel) using a preset colour model. Fully observable Markov decision process (MDP). This technique assumes the world is fully observable; it does not take into account hidden variables, such as user responsiveness. Audio prompts with three levels of assistance (minimal, moderate, and maximal) for each step. 4 [20, 3739]
Version 3 (system presented in this paper) Colour based flocking. [Belief monitoring system & policy] Partially observable Markov decision process (POMDP). This model takes into account hidden variables and is able to make decisions in conditions of uncertainty. Audio and audio-video prompts with three levels of assistance (minimal, maximal, and maximal + video demonstration) for each step. Encouragement and a reminder regarding the activity the user is attempting added. Professional actor recorded prompts. 6 [18, 19, 21, 23, 25]
  1. * Results from previous trials are not presented as they are not comparable because of the variance in the technologies and procedures that were used.