Ziaedin Shafiei

An approach for tuning PID-type controllers is developed for single input single-output, linear time-invariant systems, based on an extension to the method of D-partition. This method permits design for simultaneous minimum gain and phase margin requirements. It also allows design for specified maximum gain and phase cross-over frequencies of the c...

This paper presents an approach for finding regions of specified gain margins (GM) and phase margins (PM) in the parameter space of a single-input single-output (SISO) control system with adjustable parameters. The method uses the Nyquist stability criterion of encirclement of a point in the polar plot. The necessary boundaries of the specified GM...

A graphical technique for tuning PID-type controllers based on the method of D-partition is proposed for single-input-single-output linear time invariant systems. The tuning method shifts all the roots of the characteristic equation of the controlled system to a certain desirable region in the left half of the complex plane (LHP) to achieve a speci...

The idea of time dilation was initially proposed by Einstein in 1905 [1] as one component/consequence of the theory of special relativity (SR). Based on a thought, not real, experiment it maintains that a light clock which is moving away from an observer with a constant speed, goes slower in comparison with a stationary clock. This slower tick is i...

This article presents and critically reviews Feynman’s analysis and calculation of electromagnetic forces in the two inertial reference frames as described by Einstein in his 1905 paper. Einstein claimed that “If a unit electric point charge is in motion in an electromagnetic field, the force acting upon it is equal to the electric force which is...

Our scientific landscape is riddled with pre-scientific and non-scientific assertions.

A search for a genuine religion.

This document is a short description of Equivalence Principle (EP) analogies and its well-known critics. The document also introduces a new EP based on Uniform Deceleration of a spaceship in open space. This new analogy results in a different curvature of light in comparison to what original EP has established using uniform acceleration. The author...

The theory of length contraction was initially proposed to uphold the existence of aether after the surprise null result from Michelson and Morley (M&M) experiment. The theory claimed that any physical object shrinks in the direction of its movement through aether. The concept is accepted by special relativity by performing a thought experiment wit...

A design method is developed to ensure relative stability in terms of specific gain margins and phase margins of single input single output (SISO) discrete control systems with perturbed or adjustable coefficients. The method is a graphical parameter space technique based on fundamental Nyquist stability criteria through the method of D-partition.

The development process for powertrain control systems is intensive of time, effort and skill. With the availability of integrated CAE tools for control system design, simulation and implementation the automotive industry is moving towards model based design and analysis techniques to speed development and provide more robust control solutions. Tod...

The development process for powertrain control systems is intensive of time, effort and skill. With the availability of integrated CAE tools for control system design, simulation and implementation the automotive industry is moving towards model based design and analysis techniques to speed development and provide more robust control solutions. Tod...