Developing FPGA-based Embedded Controllers Using Matlab/Simulink

Field Programmable Gate Arrays (FPGAs) are emerging as suitable platforms for implementing embedded control systems. FPGAs offer advantages such as high performance and concurrent computing which makes them attractive in many embedded applications. As reconfigurable devices, they can be used to build the hardware and software components of an embedded system on a single chip. Traditional FPGA design flows and tools, requiring the use of Hardware Description Languages (HDLs), are in a different domain than standard control system design tools such as MATLAB/Simulink. This paper illustrates development of FPGA-based controllers by utilizing popular tools such as MATLAB/Simulink available for the design and development of control systems. The capability of DSP Builder is extended by developing a custom library of control system building blocks that facilitates rapid development of FPGA-based controllers in the familiar Matlab/Simulink environment. As a case study, this paper presents how the tools can be utilized to develop a FPGA-based controller for a laboratory scale air levitation system

A Design Methodology for MPEG-21 based Digital Policy Management Systems

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The Role of Electron-electron Interactions in Graphene ARPES Spectra

We report on a theoretical study of the influence of electron-electron interactions on ARPES spectra in graphene that is based on the random-phase-approximation and on graphene's massless Dirac equation continuum model. We find that level repulsion between quasiparticle and plasmaron resonances gives rise to a gap-like feature at small k. ARPES spectra are sensitive to the electron-electron interaction coupling strength $\alpha_{\rm gr}$ and might enable an experimental determination of this material parameter.Comment: 5 Pages, 4 Figures, Submitte

Coulomb-driven broken-symmetry states in doubly gated suspended bilayer graphene

The non-interacting energy spectrum of graphene and its bilayer counterpart consists of multiple degeneracies owing to the inherent spin, valley and layer symmetries. Interactions among charge carriers are expected to spontaneously break these symmetries, leading to gapped ordered states. In the quantum Hall regime these states are predicted to be ferromagnetic in nature whereby the system becomes spin polarized, layer polarized or both. In bilayer graphene, due to its parabolic dispersion, interaction-induced symmetry breaking is already expected at zero magnetic field. In this work, the underlying order of the various broken-symmetry states is investigated in bilayer graphene that is suspended between top and bottom gate electrodes. By controllably breaking the spin and sublattice symmetries we are able to deduce the order parameter of the various quantum Hall ferromagnetic states. At small carrier densities, we identify for the first time three distinct broken symmetry states, one of which is consistent with either spontaneously broken time-reversal symmetry or spontaneously broken rotational symmetry

Experimental and numerical validation of active flaps for wind turbine blades

An industrial active flap concept for wind turbine rotor blades is validated numerically by means of CFD, as well as experimentally in a wind tunnel environment. This paper presents the numerical and experimental results, as well as a discussion regarding the testing of airfoils equipped with active flaps with a highly loaded aft portion. A conceptual implementation for an offshore wind turbine and the potential for load reduction is shown by means of aeroelastic calculations. The work presented herein is conducted within the frame of the Induflap2 project and is partially funded by the Danish funding board EUDP

Numerical studies of the fractional quantum Hall effect in systems with tunable interactions

The discovery of the fractional quantum Hall effect in GaAs-based semiconductor devices has lead to new advances in condensed matter physics, in particular the possibility for exotic, topological phases of matter that possess fractional, and even non-Abelian, statistics of quasiparticles. One of the main limitations of the experimental systems based on GaAs has been the lack of tunability of the effective interactions between two-dimensional electrons, which made it difficult to stabilize some of the more fragile states, or induce phase transitions in a controlled manner. Here we review the recent studies that have explored the effects of tunability of the interactions offered by alternative two-dimensional systems, characterized by non-trivial Berry phases and including graphene, bilayer graphene and topological insulators. The tunability in these systems is achieved via external fields that change the mass gap, or by screening via dielectric plate in the vicinity of the device. Our study points to a number of different ways to manipulate the effective interactions, and engineer phase transitions between quantum Hall liquids and compressible states in a controlled manner.Comment: 9 pages, 4 figures, updated references; review for the CCP2011 conference, to appear in "Journal of Physics: Conference Series

Association between serum secretory phospholipase A2 and risk of ischaemic stroke

Background and purpose: Previous literature has demonstrated an association between high serum levels of type II secretory phospholipase A2 (sPLA2) concentration and an increased risk of coronary artery disease. However, such association has not been established in terms of ischaemic stroke risk. The aim was to evaluate the association between both sPLA2 concentration and activity as continuous variables with risk of future ischaemic stroke. / Methods: A nested case–control study was conducted using data from the European Prospective Investigation into Cancer—Norfolk study. Cases (n = 145) in the current study were participants who developed ischaemic stroke during follow-up, with controls (n = 290) matched in a 2:1 ratio based on age and sex. Statistical analyses were performed using SPSS (version 25.0) software. Logistic regression was used to determine odds ratios (OR) and corresponding 95% confidence intervals (95% CIs) for ischaemic stroke. / Results: After adjusting for a wide array of cardiovascular confounders, sPLA2 activity was found to be associated with an increased risk of ischaemic stroke using both multiple imputations with chained equations and complete case analysis: OR 1.20 (95% CI 1.01–1.43) and OR 1.23 (95% CI 1.01−1.49), respectively. However, sPLA2 concentration was not found to be associated with increased risk of ischaemic stroke. / Conclusions: The activity of sPLA2, but not sPLA2 concentration, is associated with an increased risk of future ischaemic stroke. This finding may be significant in risk group stratification, allowing targeted prophylactic treatment, or the development of novel therapeutic agents