Density is a synonym of Concentration. Concentration is a type of Increase. Increase is related to Big. 
Pulse is related to Shock. Shock is related to Accident. one thing you do when you Perform is Accident. Perform requires Artist. 
Density <--Synonym--> Concentration --IsA--> Increase <--RelatedTo--> Big 
Pulse <--RelatedTo--> Shock <--RelatedTo--> Accident <--HasSubevent-- Perform --HasPrerequisite--> Artist 