A converter can include at least two power stages. The vehicle brake system may include a friction brake and a secondary brake that may be applied to slow rotation of a vehicle wheel when a wheel slip condition is detected. Each of the electric bikes comprises a monitor module and a portable electric device, wherein the portable device further comprises a storing unit and a WiFi module. Each conditional mean is the Bayes optimal estimate given the specific local context. Keywords include smart pen and on set metadata acquisition. The electronic device may also include an event queue.