I had a trip to Quebec city for 4 days. Behind the lingering from the travel, I prepared for the meetup this week. I could not join it because of birthday dinner with my girlfriend. However, I studied the original paper seriously, and the topic involves some interesting ideas, so I want to introduce about it. Long short term memory (LSTM) To understand the paper, precedently, need to understand LSTM. I recommend chapter 10 of the deeplearning book.