Situation semantics pioneered by Jon Barwise and John Perry in the early 1960s) attempts to provide a solid theoretical foundation for reasoning about common-sense and real-world situations, typically in the context of theoretical linguistics, theoretical philosophy, or applied natural language processing,Situation semantics is the first semantic theory that was used in head-driven phrase structure grammar (HPSG).
In situation theory, situation semantics (pioneered by Jon Barwise and John Perry in the early 1980s) attempts to provide a solid theoretical foundation for reasoning about common-sense and real world situations, typically in the context of theoretical linguistics, theoretical philosophy, or applied natural language processing, Situation semantics is the first semantic theory that was used in head-driven phrase structure grammar (HPSG). 
