Search results for "vector [correlation function]"
showing 10 items of 339 documents
- EL EFECTO FISHER Y LA PARIDAD DE INTERÉS REAL. EVIDENCIA PARA LA ECONOMÍA ESPAÑOLA
1999
This paper provides an empirical test of the Fisher effect and of the real interest parity. The objetive is to determinate the behavior of the ex-ante real interest that condicionate the intertemporal savings and investment decisions. The method used is the time series properties of the data, which allows to separate estimation of the long-run equilibrium relationship from the nuisance parameters that characterize the short-run dynamics. The results find support inthe long run for a tax-adjusted Fisher hypothesis but not for the real interest parity. En este trabajo se contrasta empíricamente el cumplimiento de la hipótesis de Fisher y de la paridad de interés real para el caso español. El …
Real wages-employment relationship in Finnish manufacturing: a VAR approach
1991
Granger's concept of causality and the vector autoregressive(VAR) technique is used to investigate the real wages-employment relationship in Finnish manufacturing. The stationarity of the time series is examined and a number of co-integration tests for the adequacy of a pure VAR specification performed. The results using a bivariate VAR model based on a lag structure determined by Akaike's information criterion suggests that real wages Granger-cause employment. The slight non-constancy of the model suggests, however, that the conclusion concerning the nature of the real wages-emploment relationship should be treated with causion.
On the international co-movement of natural interest rates
2022
Using quarterly data for 10 OECD countries and the Euro area and a Kalman filtering technique, we investigate the international co-movement among natural interest rates. We show that the US is the main source of global spillovers and global/common factors appear to be key drivers of such co-movement. Indeed, global liquidity is a net transmitter of shocks, while quantitative easing (QE) and the US Dollar are net recipients of shocks. We also find that total spillovers among natural interest rates have been rising since the late nineties, spiking at around economic re-cessions, periods of US monetary policy tightening, the global financial crisis and the Eurozone sovereign debt crisis. From …
Dynamical Compensation of the Load Torque in a High-Performance Electrical Drive with an Induction Motor
2018
This paper describes a new method for dynamical estimation of load disturbance in induction motors by using Nonlinear Unknown Input Observers (NUIO). This estimation is then used to compensate dynamically the load torque in a Field Oriented Control (FOC) induction motor drive to increase its load-rejection capability. The method has been verified both in simulation and experimentally on a experimental rig.
The electromagnetic and Proca fields revisited: A unified quantization
1997
Quantizing the electromagnetic field with a group formalism faces the difficulty of how to turn the traditional gauge transformation of the vector potential, Aμ(x) → Aμ(x) + ∂μφ(x), into a group law. In this paper, it is shown that the problem can be solved by looking at gauge transformations in a slightly different manner which, in addition, does not require introducing any BRST-like parameter. This gauge transformation does not appear explicitly in the group law of the symmetry but rather as the trajectories associated with generalized equations of motion generated by vector fields with null Noether invariants. In the new approach the parameters of the local group, U(1)(x, t), acquire dyn…
Highly efficient full-wave electromagnetic analysis of 3-D arbitrarily shaped waveguide microwave devices using an integral equation technique
2015
A novel technique for the full-wave analysis of 3-D complex waveguide devices is presented. This new formulation, based on the Boundary Integral-Resonant Mode Expansion (BI-RME) method, allows the rigorous full-wave electromagnetic characterization of 3-D arbitrarily shaped metallic structures making use of extremely low CPU resources (both time and memory). The unknown electric current density on the surface of the metallic elements is represented by means of Rao-Wilton-Glisson basis functions, and an algebraic procedure based on a singular value decomposition is applied to transform such functions into the classical solenoidal and nonsolenoidal basis functions needed by the original BI-RM…
Robust Active Disturbance Rejection Control of Induction Motor Systems Based on Additional Sliding-Mode Component
2017
This paper deals with motion control systems with induction motor, subject to severe requirements on both dynamics and steady-state behavior. The proposed control methodology could be viewed as an advancement of the standard field oriented control. It consists of two control loops, i.e., the rotor flux and the speed control loops, designed using the active disturbance rejection control method, with the aim to cope with both exogenous and endogenous disturbances, which are estimated by means of two linear extended state observers and then compensated. Moreover, with the aim of achieving total robustness, a sliding-mode based component is designed, in order to take into account disturbance es…
Input-Output Feedback Linearization Control of Linear Induction Motors Including the dynamic End-Effects
2014
This paper proposes the theoretical framework and the consequent application of the input-output feedback linearization (FL) control technique to linear induction motors (LIM). LIM, additionally to RIM, presents other strong non-linearities caused by the dynamic end effects, leading to a space-vector dynamic model with time-varying inductance and resistance terms and a braking force term. This paper, starting from a recently developed dynamic model of the LIM taking into consideration its end effects, defines a FL technique suited for LIMs, since it inherently considers its dynamic end effects. The proposed approach has been validated experimentally on a suitably developed test set-up. Furt…
Unit Vector Fields that are Critical Points of the Volume and of the Energy: Characterization and Examples
2007
In the last few years, many works have appeared containing examples and general results on harmonicity and minimality of vector fields in different geometrical situations. This survey will be devoted to describe many of the known examples, as well as the general results from where they are obtained.
Experimental investigation on high efficiency real-time control algorithms for IPMSMs
2014
This paper describes an experimental investigation on the power losses variations occurring in an Interior Permanent Magnet Synchronous Motor (IPMSM) with respect to the direct axis current component. Such investigation can be useful to determine a mathematical model accounting for copper, iron and mechanical friction losses, and for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. In particular, a test bench has been set up in order to carry out all measurements and the final power loss identification. The test bed is composed by a IPMSM drive with a field oriented control (FOC) strategy, a power analyzer, a dynamometric brake a…