Search results for " and Control"
showing 10 items of 385 documents
H<inf>&#x221E;</inf> synchronization of Markovian jump master-slave systems with delay
2012
The problem of synchronization is investigated for a class of master-slave systems with time-varying delays and Markovian switching parameters. Using an appropriate Lyapunov-Krasovskii functional, a synchronization law which includes the master-slave parameters is established for designing a mode-dependent output feedback control law in terms of LMIs. A numerical example is given to show the effectiveness of the method.
On the Effects of Relative Performance Feedback in a Risk Elicitation Task: Evidence From a Lab Experiment
2018
This paper experimentally investigates the influence of different non-payoff-relevant feedback regimes on motivation, competitiveness and risk-taking behaviors in a risk elicitation task. We explore four feedback regimes: private feedback, full ranking feedback, top-5 ranking feedback, and non-ranking feedback based on the median performance of peers. We found that providing relative performance feedback increases risk-taking behavior, especially when using a top-5 ranking. Feedback regimes that provide a user with rank-based feedback have adverse effects on the users' attitudes as they increase competitiveness while failing to increase intrinsic motivation and performance motivation. In co…
Modelling anaerobic biomass growth kinetics with a substrate threshold concentration.
2004
Abstract Many bacteria have been observed to stop growing below a certain substrate threshold concentration. In this study, a modification of the Monod kinetics expression has been proposed to take into account this substrate threshold concentration observed in bacterial growth. Besides the threshold concentration no additional parameters have been added to the kinetic expression and so, only the substrate threshold concentration and the half-saturation constant have to be estimated for model calibration purposes. Furthermore, for parameter estimation purposes, practical identifiability of this new function has been studied and the results have been satisfactory. The new model has been appl…
Cluster analysis for portfolio optimization
2005
We consider the problem of the statistical uncertainty of the correlation matrix in the optimization of a financial portfolio. We show that the use of clustering algorithms can improve the reliability of the portfolio in terms of the ratio between predicted and realized risk. Bootstrap analysis indicates that this improvement is obtained in a wide range of the parameters N (number of assets) and T (investment horizon). The predicted and realized risk level and the relative portfolio composition of the selected portfolio for a given value of the portfolio return are also investigated for each considered filtering method.
Impulse-based hybrid motion control
2017
The impulse-based discrete feedback control has been proposed in previous work for the second-order motion systems with damping uncertainties. The sate-dependent discrete impulse action takes place at zero crossing of one of both states, either relative position or velocity. In this paper, the proposed control method is extended to a general hybrid motion control form. We are using the paradigm of hybrid system modeling while explicitly specifying the state trajectories each time the continuous system state hits the guards that triggers impulsive control actions. The conditions for a stable convergence to zero equilibrium are derived in relation to the control parameters, while requiring on…
Full- and Reduced-order Model of Hydraulic Cylinder for Motion Control
2017
This paper describes the full- and reduced-order models of an actuated hydraulic cylinder suitable for system dynamics analysis and motion control design. The full-order model incorporates the valve spool dynamics with combined dead-zone and saturation nonlinearities - inherent for the orifice flow. It includes the continuity equations of hydraulic circuits coupled with the dynamics of mechanical part of cylinder drive. The resulted model is the fifth-order and nonlinear in states. The reduced model neglects the fast valve spool dynamics, simplifies both the orifice and continuity equations through an aggregation, and considers the cylinder rod velocity as output of interest. The reduced mo…
The UWB-OFDM Channel Analysis in Frequency
2009
In this paper, the ultra-wideband channel with orthogonal frequency division multiplexing (UWB-OFDM) is analyzed in the frequency domain. For UWB-OFDM channels with log-normal fading in the time domain, we show that the amplitude of each subcarrier can be approximated by a Nakagami-m random variable, where the fading parameter, the mean power and the correlation coefficient are expressed in terms of the following parameters: time arrival of the clusters, inter-arrival time of rays inside clusters, and power decay constants of rays and clusters.
Optical studies of gap, hopping energies, and the Anderson-Hubbard parameter in the zigzag-chain compoundSrCuO2
2001
We have investigated the electronic structure of the zig-zag ladder (chain) compound ${\mathrm{SrCuO}}_{2}$ combining polarized optical absorption, reflection, photoreflectance, and pseudo-dielectric-function measurements with the model calculations. These measurements yield an energy gap of 1.42 eV (1.77 eV) at 300 K along (perpendicular to) the Cu-O chains. We have found that the lowest-energy gap, the correlation gap, is temperature independent. The electronic structure of this oxide is calculated using both the local-spin-density approximation with gradient correction method and the tight-binding theory for the correlated electrons. The calculated density of electronic states for noncor…
Resonant rayleigh scattering in semiconductor structures
1995
A detailed study of the relative role played by localized and/or propagating intermediate excitonic states in, resonant Rayleigh scattering (RRS) is presented for a large set of GaAs quantum well (QW) and bulk structures. We show that the two kinds of states contribute to RRS through different mechanisms. We concluded that RRS occurs via localized states in QW heterostructures, very likely due to localization by the interface roughness, while bulk, crystals turn out to be better candidates for RRS via propagating states.
Constraints on millicharged dark matter and axionlike particles from timing of radio waves
2019
We derive novel constraints on millicharged dark matter and ultralight axion-like particles using pulsar timing and fast radio burst observations. Millicharged dark matter affects the dispersion measure of the time of arrival of radio pulses in a way analogous to free electrons. Light pseudo-scalar dark matter, on the other hand, causes the polarization angle of radio signals to oscillate. We show that current and future data can set strong constraints in both cases. For dark matter particles of charge $\epsilon e$, these constraints are ${\epsilon}/{m_{\rm milli}} \lesssim 10^{-8}{\rm eV}^{-1}$, for masses $m_{\rm milli}\gtrsim 10^{-6}\,$eV. For axion-like particles, the analysis of signal…