Discovery is related to Shock. Shock is related to Alarm. Horn is a type of Alarm. 
Plan is related to Scheme. Scheme is a synonym of System. Network is a type of System. 
Discovery <--RelatedTo--> Shock <--RelatedTo--> Alarm <--IsA-- Horn 
Plan <--RelatedTo--> Scheme <--Synonym--> System <--IsA-- Network 