Entradas

Mostrando las entradas de agosto, 2017

FPA Algorithm

Flower Pollination Algorithms The flower pollination algorithm (FPA) was developed by Xin-She Yang in 2012, inspired by the pollination process of flowering plants. FPA has been extended to multiobjective optimization with promising results. This chapter provides an introduction to FPA and its basic implementation. 11.1 Introduction Real-world design problems in engineering and industry are usually multi-objective or multicriteria. These multiple objectives often conflict with one another, which makes it impossible to use any single design option without compromise. Common approaches are to provide good approximations to the true Pareto fronts of the problem of interest so that decision makers can rank different options, depending on their preferences or their utilities [1,5,15]. Compared with single-objective optimization, multi-objective optimization has its additional challenging issues such as time complexity, inhomogeneity, and dimensionality. It is usua

PWM with transistor

Imagen
The PWM control is used to generate a PWM output signal on an output port.  A PWM signal is a pulse that repeats at a fixed frequency.  The width of the pulse can be varied from 0 to 100%. The image above shows the PWM signal, plotting the output voltage against time.  The period specifies the time the pulse repeats.  The frequency of the signal is 1 / period, where the period is in seconds.  In the example above, the pulse width, or duty cycle, is about 66%. The frequency of the PWM signal and the resolution of the pulse width are defined as characteristics of the microcontroller.  See the section on  timers  for more information. The frequency of the PWM signal can be configured to be anything from 0.1Hz to 4MHz.  For controlling LED brightness anything above 1kHz is fine. So what is a PWM signal used for?  In a HID device, they can be used for driving LEDs and other external loads.  Hooking up an  RGB LED  to 3 PWM outputs will give infinite colour control of the LED.  Th