Commutation with codes

Quantum error correcting codes and Weyl commutation relations

This is mainly an expository account of the general theory of quantum error correcting codes exploiting the commutation relations between the Weyl operators associated with a finite additive abelian group. There are some new elements of proofs and remarks, particularly, in the context of the Knill-Laflamme theorem [5].

A Family of Quantum Stabilizer Codes Based on the Weyl Commutation Relations over a Finite Field

Using the Weyl commutation relations over a finite field Fq we introduce a family of error-correcting quantum stabilizer codes based on a class of symmetric matrices over Fq satisfying certain natural conditions. When q = 2 the existence of a rich class of such symmetric matrices is demonstrated by a simple probabilistic argument depending on the Chernoff bound for i.i.d symmetric Bernoulli tri...

The Influence of DC-Link Voltage on Commutation Torque Ripple of Brushless DC Motors with Two-Segment Pulse-width Modulation Control Method

The commutation process causes current ripple to be generated in the drive system of brushless DC (BLDC) motor. This, in turn, leads to output torque ripple. Mechanical vibration and acoustic noise are its influences which are undesirable phenomenon in some applications. A new method is presented in this paper which reduces torque ripple and commutation period in the entire range of motor speed...

A Neural Network-PSO Based Control for Brushless DC Motors for Minimizing Commutation Torque Ripple

This paper presents the method of reducing torque ripple of brushless DC (BLDC) motor. The commutation torque ripple is reduced by control of the DC link voltage during the commutation time. The magnitude of voltage and commutation time is estimated by a neural network and optimized with an optimization method named particle swarm optimization (PSO) algorithm analysis. The goal of optimizati...

Codes with a Certain Weight-preserving Transitive Group of Automorphisms

We determine all linear codes C containing the constant code E, for which there is a weight-preserving group of semilinear automorphisms which acts transitively on the set of nontrivial cosets of E in C.

On Commutation and Primitive Roots of Codes