The paper introduces the Generalized Temporal Role Based Access Control (GTRBAC) model, which extends the Temporal Role Based Access Control (TRBAC) model to handle a broader range of temporal constraints. TRBAC focuses on role enabling, but GTRBAC supports both periodic and duration constraints on roles, user-role assignments, and role-permission assignments. GTRBAC allows for separate specification of temporal constraints on role enabling and activation, and enables activation constraints such as cardinality and maximum active duration. The model introduces the notion of constraint enabling and disabling, and distinguishes between role enabling and activation to better handle static and dynamic constraints. The paper also discusses the use of periodic expressions to represent time intervals and the formalization of temporal constraints in GTRBAC. Examples illustrate how GTRBAC can be applied to real-world scenarios, such as managing access to hospital resources and controlling access to online courses. The model is formalized with a syntax and semantics for constraint expressions, including periodicity, duration, and activation constraints. The paper also defines conflicting events and the principle of negative-takes-precedence to resolve conflicts. The GTRBAC model is shown to be applicable in various scenarios, including managing access to video libraries and enforcing access policies in online courses. The paper concludes with a discussion of related work and future research directions.The paper introduces the Generalized Temporal Role Based Access Control (GTRBAC) model, which extends the Temporal Role Based Access Control (TRBAC) model to handle a broader range of temporal constraints. TRBAC focuses on role enabling, but GTRBAC supports both periodic and duration constraints on roles, user-role assignments, and role-permission assignments. GTRBAC allows for separate specification of temporal constraints on role enabling and activation, and enables activation constraints such as cardinality and maximum active duration. The model introduces the notion of constraint enabling and disabling, and distinguishes between role enabling and activation to better handle static and dynamic constraints. The paper also discusses the use of periodic expressions to represent time intervals and the formalization of temporal constraints in GTRBAC. Examples illustrate how GTRBAC can be applied to real-world scenarios, such as managing access to hospital resources and controlling access to online courses. The model is formalized with a syntax and semantics for constraint expressions, including periodicity, duration, and activation constraints. The paper also defines conflicting events and the principle of negative-takes-precedence to resolve conflicts. The GTRBAC model is shown to be applicable in various scenarios, including managing access to video libraries and enforcing access policies in online courses. The paper concludes with a discussion of related work and future research directions.