Random Sequential Generation of Intervals for the Cascade Model of Food Webs

The cascade model generates a food web at random. In it the species are labeled from 0 to $m$, and arcs are given at random between pairs of the species. For an arc with endpoints $i$ and $j$ ($i<j$), the species $i$ is eaten by the species labeled $j$. The chain length (height), generated at random, models the length of food chain in ecological data. The aim of this note is to introduce the random sequential generation of intervals as a Poisson model which gives naturally an analogous behavior to the cascade model

An Approximate PML Applied to Cylindrical and Spherical Coordinate Sectors

This letter proposes an approximate perfectly matched layer (PML) that is applicable to cylindrical and spherical coordinate sectors. The proposed PML is based on complex coordinate stretching, which enables the truncation of finite-difference time-domain (FDTD) grids, not only at the ρ- and r-coordinates but also at the φ- and θ-coordinates. The absorption performance of the PML is demonstrated through numerical simulations