IHACRES model is a lumped conceptual rainfall runoff model based on unit hydrograph principle. It is composed of two basic modules in series: in the nonlinear module, rainfall is transformed into effective rainfall; in the linear module, effective rainfall is further transformed into runoff. The model is suitable for a series of spatial and temporal scales.

IBIS model is used to describe the input, output and I / obuffer behavior characteristics of IC devices, and to simulate the interaction between buffer and on-board circuit system. The core content of IBIS model is the buffer model, because these buffers produce some simulated waveforms, so the simulator uses these waveforms to simulate the influence of transmission line and some high-speed phenomena. Specifically, Ibis describes the input and output impedances (in the form of I / V curves), rise and fall times, as well as pull-up and pull-down in different situations. Engineers can use this model to analyze Si, crosstalk, EMC and timing in the circuit system on PCB.