“…Large numbers of heterogeneous digital devices and communication nodes are being incorporated into the Internet [6,14,65,99,111] to manage cities and various service activities [3,9,10,13,36,62,116], which also leads to more energy consumption by ICT. Such systems must operate autonomously over a long period, and can benefit from collecting energy physically from natural phenomena such as wind, liquid flows, photovoltaic energy, and other renewable energy sources.…”