Opinion Mining

Opinion to a Machine is a Quintuple (an object made of 5 elements) - (O, f, SO, H, t)

• O - the thing in question, 
• f - the feature of O, 
• SO the Opinion value, 
• h the opinion holder, 
• t the time at which the opinion is given.

Source : Bing Liu in NLP Manual (slide 9 of 21 on http://www.slideshare.net/mcjenkins/how-sentiment-analysis-works)