Research on version updates of LOL and player activity
  I found that those players who cling to some particular champions may often have different feeling on each patch. The balance patch is supposed to improve the user experience of the players, but often we can see that when the players¡¯ favorite champion, or item, has been nerfed, they may often show the negative attitude during the whole game. From another point of view, when a champion has been nerfed, at the same time, also represents the other champions are 
stronger against it more or less. Many players also use other champions more frequently, which indicates that the substitution effect between different champions may also affects the player's activity
  Therefore, I would like to take this phenomenon as the direction of my research paper and try to discover the reasons behind it. The data crawling part is based on Riot API and a Python wrapper Riot-Watcher. A Mongo database is designed and used in this projec