id	keyword
etr-25839	event
etr-25839	crowd
etr-25839	tourism
etr-25839	review
etr-25839	management
etr-25839	app
etr-25839	liu
etr-25839	lastres
etr-25839	weaver
etr-25839	attendees
etr-25839	location
etr-25839	risk
etr-25839	tourism review
etr-25839	technologies
etr-25839	mitigation
etr-25839	time