4,298 research outputs found
A CSP-Based Trajectory for Designing Formally Verified Embedded Control Software
This paper presents in a nutshell a procedure for producing formally verified concurrent software. The design paradigm provides means for translating block-diagrammed models of systems from various problem domains in a graphical notation for process-oriented architectures. Briefly presented CASE tool allows code generation both for formal analysis of the models of software and code generation in a target implementation language. For formal analysis a highquality commercial formal checker is used
gCSP: A Graphical Tool for Designing CSP systems
For broad acceptance of an engineering paradigm, a graphical notation and a supporting design tool seem necessary. This paper discusses certain issues of developing a design environment for building systems based on CSP. Some of the issues discussed depend specifically on the underlying theory of CSP, while a number of them are common for any graphical notation and supporting tools, such as provisions for complexity management and design overview
Self consistent thermal wave model description of the transverse dynamics for relativistic charged particle beams in magnetoactive plasmas
Thermal Wave Model is used to study the strong self-consistent Plasma Wake
Field interaction (transverse effects) between a strongly magnetized plasma and
a relativistic electron/positron beam travelling along the external magnetic
field, in the long beam limit, in terms of a nonlocal NLS equation and the
virial equation. In the linear regime, vortices predicted in terms of
Laguerre-Gauss beams characterized by non-zero orbital angular momentum (vortex
charge). In the nonlinear regime, criteria for collapse and stable oscillations
is established and the thin plasma lens mechanism is investigated, for beam
size much greater than the plasma wavelength. The beam squeezing and the
self-pinching equilibrium is predicted, for beam size much smaller than the
plasma wavelength, taking the aberrationless solution of the nonlocal Nonlinear
Schroeding equation.Comment: Poster presentation P5.006 at the 38th EPS Conference on Plasma
Physics, Strasbourg, France, 26 June - 1 July, 201
Nanosecond-timescale spin transfer using individual electrons in a quadruple-quantum-dot device
The ability to coherently transport electron-spin states between different
sites of gate-defined semiconductor quantum dots is an essential ingredient for
a quantum-dot-based quantum computer. Previous shuttles using electrostatic
gating were too slow to move an electron within the spin dephasing time across
an array. Here we report a nanosecond-timescale spin transfer of individual
electrons across a quadruple-quantum-dot device. Utilizing enhanced relaxation
rates at a so-called `hot spot', we can upper bound the shuttle time to at most
150 ns. While actual shuttle times are likely shorter, 150 ns is already fast
enough to preserve spin coherence in e.g. silicon based quantum dots. This work
therefore realizes an important prerequisite for coherent spin transfer in
quantum dot arrays.Comment: 7 pages including 2 pages of supplementary materia
Integrating PLCs with Robot Motion Control in Engineering Capstone Courses
Robotic motion control methods and Programmable Logic Controllers (PLCs) are critical in engineering automation and process control applications. In most manufacturing and automation processes, robots are used for moving parts and are controlled by industrial PLCs. Proper integration of external I/O devices, sensors and actuating motors with PLC input and output cards is very important to run the process smoothly without any faults and/or safety concerns. Most traditional electrical and computer engineering (ECE) programs offer high level of motion theory and controls but little hands-on exposure to PLCs which are the main industrial controllers. This paper provides a framework for a hands-on project to integrate PLCs in robot arm motion control, troubleshooting, and testing the real sensors and motors with PLC experiments which complements the virtual calculations and theory. This PLC with Robot Arm Motion control integration concept idea was introduced and tested in a 600-level graduate capstone project class. By the end of the semester long class, the students used their PLC hardware and software skills to wire a robot arm sensing elements and actuating motors to pick and place objects from one location to a bin. The assessment demonstrated that the course learning objectives were met
Quantum kinetic description of Coulomb effects in one-dimensional nano-transistors
In this article, we combine the modified electrostatics of a one-dimensional
transistor structure with a quantum kinetic formulation of Coulomb interaction
and nonequilibrium transport. A multi-configurational self-consistent Green's
function approach is presented, accounting for fluctuating electron numbers. On
this basis we provide a theory for the simulation of electronic transport and
quantum charging effects in nano-transistors, such as gated carbon nanotube and
whisker devices and one-dimensional CMOS transistors. Single-electron charging
effects arise naturally as a consequence of the Coulomb repulsion within the
channel
Spectral Properties of Acoustic Gravity Wave Turbulence
The nonlinear turbulent interactions between acoustic gravity waves are
investigated using two dimensional nonlinear fluid simulations. The acoustic
gravity waves consist of velocity and density perturbations and propagate
across the density gradients in the vertical direction in the Earth's
atmosphere. We find that the coupled two component model exhibits generation of
large scale velocity potential flows along the vertical direction, while the
density perturbations relax towards an isotropic random distribution. The
characteristic turbulent spectrum associated with the system has a
Kolmogorov-like feature and tends to relax towards a spectrum, where
is a typical wavenumber. The cross field diffusion associated with the
velocity potential grows linearly and saturates in the nonlinear phase
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