covid_theme             keywords relating to COVID-19 pandemics
debate_dtd              Comments on a video of a political debate.
opi_impact              Statistical assessment of impacts of a
                        specified theme from a DTD.
opi_score               Opinion score of a digital text document (DTD)
opi_sim                 Simulates the opinion expectation distribution
                        of a digital text document.
osd_data                Observed sentiment document (OSD).
policing_dtd            Twitter posts on police/policing
refreshment_theme       Keywords relating to facilities at train
                        stations
reviews_dtd             Customer reviews from tripadvisor website
signage_theme           Keywords relating to signages at train stations
tweets                  Fake Twitter posts on police/policing 2
word_distrib            Words Distribution
word_imp                Importance of words (terms) embedded in a text
                        document
