1.Systems that combine time-driven with event-driven dynamics are referred to as Hybrid Systems.
2.Summary of system classifications:
Static and Dynamic Systems.In static systems the output is always independent of past values of the input.In dynamic systems,the output does depend on past values of the input.（想到迭代算法，动态的系统有相同之处）
Time-varying and Time-invariant Systems.The behavior of time-invariant systems does not change with time.(想到分段函数，自变量的某个范围内，函数值不发生变化)
Linear and Nonlinear Systems.A linear system satisfies the condition g(a1u1+a2u2)=a1g(u1)+a2g(u2),(想到高等数学中学习，如果两个函数极限都存在，则他们的线性组合极限也存在，线性关系满足相加定理)
Continuous-state and Discrete-State Systems.In continuous-state systems, the state variables can generally take on any real(or complex)value.in discrete-state systems,the state variables are elements of a discrete set.(想到概率统计里说道，离散事件的概率及连续事件的概率)。
Time-driven and Event-driven Systems.In time-driven systems, the state continuously changes as time changes. In event-driven systems,it is only the occurrence of asynchronously generated discrete events that forces instantaneous state transitions.(time-driven system 使我想到了连续函数，event-driven system使我想起了进程在就绪态等待，资源或者时间片的到来，等待事件的发生，以便进行状态的转换)。
Deterministic and Stochastic Systems.A system becomes stochastic whenever one or more of its output variables is a random variable.(想到C++中随机函数)
Discrete-time and Continuous-time Systems.A continuous-time system is one where all input .state,and output variables are defined for all possible values of time.In discrete-time systems,one or more of these variables are defined at discrete points in time only, usually as the result of some sampling process.(想到概率中的离散事件)。
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