“…Most conventional recommendation systems use cosine similarity (Lu et al , 2012; Shamir and Tishby, 2010) or k -means algorithms (Li et al , 2008) to combine the multi-dimensional data of a user into a single score, and then search for similar users based on this score. However, this approach is actually highly illogical – as the dimensions of user data are independent and unrelated, they should not be combined into a single indicator (Hou et al , 2015). For example, Tables I and II are largely similar, with the exception of Table II having an additional User G. Both Users G and A have similar ratings for the Tokyo National Museum but different ratings for the other two Tokyo attractions.…”