Observation is a type of Measurement. Measurement is related to Weigh. Weigh is a synonym of Balance. 
Place is related to Office. Office is related to Bank. Bank is the opposite of Casino. you are likely to find Security in/at/on Casino. 
Observation --IsA--> Measurement <--RelatedTo--> Weigh <--Synonym--> Balance 
Place <--RelatedTo--> Office <--RelatedTo--> Bank <--Antonym--> Casino <--AtLocation-- Security 