Abstract: I welcome you to the fourth issue of the IEEE Communications Surveys and Tutorials in 2021. This issue includes 23 papers covering different aspects of communication networks. In particular, ...

Within each content area, there are one or more tutorials. Each tutorial consists of lessons. Each lesson should be a page detailing the concept being taught, along with sample code. Lesson and page ...

This file provides functions and modules that construct shapes from a list of cross sections. In the case of skin() you specify each cross sectional shape yourself, and the number of points can vary.