The University of Texas System

University of Pa.

Michael D Bryant

Benito R Fernandez

Shouli Yan

Brian R Remy

Jau-Wen Lin

Ashish Seth

John W Hall

Benito R Fernández

Carlos A García

José R Capriles-Grané

Described herein is a combination of mixed-signal hardware and software that is capable or realizing hybrid chaotic oscillators that can be tuned digitally. This includes the type/class of chaotic oscillator, initial conditions, nonlinear elements, thresholds, nonlinear event surfaces, delays, etc. At the same time, tunable methods of how to use the chaotic oscillator information to encrypt and decrypt both analog and digital information is presented. This will make the secure information not vulnerable by digital information compromises or hardware breach.

Method and apparatus for hybrid encryption

An apparatus for solving time-continuous differential equations is disclosed. The apparatus includes a group of hybrid integrators interconnected to each other. Each one of the hybrid integrators includes an analog integrator, a conversion logic and multiple digital registers. The analog integrator generates an analog output, and the conversion logic along with the digital registers converts the analog output to a digital output. The analog output and the digital output are then combined to yield an integrated output. The integrated output is fed to the hybrid integrators within the group.

Apparatus for solving differential equations

A mixed-signal system for performing Taylor series function approximations is disclosed. The mixed-signal system includes a digital-to-analog converter (DAC), multiple resistor-to-resistor (R2R) ladders, various digital registers, a digital processor and an analog integrator. The digital processor calculates coefficients F, F, F, F, F, Fof a Taylor series equation and calculates distance functions. The digital processor also includes a digital register for storing a magnitude scaling factor &#x3c6;(x,y) of the Taylor series equation. The DAC control register uploads a lead term F(x,y) of the Taylor series equation from the digital processor to the DAC. The first-order digital registers controls resistances of the R2R ladders. The second-order digital registers uploads coefficients F, F, F, F, Fof the Taylor series equation from the digital processor to the DAC. The analog integrator adds outputs from the DAC and the R2R ladder to generate approximation results for the Taylor series equation.

Mixed-signal system for performing Taylor series function approximations

Methods and apparatus to reduce wear on surfaces in sliding contact by inducing vibratory movement in one or more of the surfaces. The movement is substantially perpendicular to a plane of contact between the surfaces and substantially nonuniform across the area of contact. The nonuniform vibratory motion of one surface with respect to another results in small rotational vibration of one surface with respect to another even as contact is maintained between the surfaces. Rotational motions tend to decrease surface wear due to thermal mounding by moving the zone of actual contact with time; rotational motions also open temporary gaps between the surfaces which allow the escape of wear particles, thus decreasing subsequent abrasive wear. The invention may be applied to sliding electrical contacts, either linear or rotating, and to sliding frictional contacts, as in brakes and clutches. Application of the invention reduces wear on electrical contacts while maintaining electrical continuity, and reduces wear on brake system components without substantially reducing effective braking force.

Methods and apparatus to reduce wear on sliding surfaces

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Austin, TX, United States of America

Michael D Bryant