Hogarthian is a way to configure equipment; according to this approach, the equipment must be as streamlined and minimalist as possible. To give you an idea, the back-mount equipment configuration used by GUE, UTD and ISE divers is a Hogarthian setup.
DIR is a philosophy of diving; at least three agencies are promoting it: GUE, UTD, and ISE.
GUE is an agency and an NGO focusing on diving education, conservationism, exploration, and citizen science projects.
Wikipedia gives some interesting (but not exhaustive) information about them:
en.wikipedia.org
en.wikipedia.org
en.wikipedia.org
EDIT: check also this link:
en.wikipedia.org