510 research outputs found
On Prediction Model Fidelity in Explicit Nonlinear Model Predictive Vehicle Stability Control
No full textThis study discusses vehicle stability control based on explicit nonlinear model predictive control (NMPC) and investigates the influence of prediction model fidelity on controller performance. The explicit solutions are generated through an algorithm using multiparametric quadratic programming (mp-QP) approximations of the multiparametric nonlinear programming (mp-NLP) problems. Controllers with different prediction models are assessed through objective indicators in sine-with-dwell tests. The analysis considers the following prediction model features: 1) nonlinear lateral tire forces as functions of slip angles, which are essential for the operation of the stability controller at the limit of handling. Moreover, a simple nonlinear tire force model with saturation is shown to be an effective alternative to a more complex model based on a simplified version of the Magic Formula; 2) longitudinal and lateral load transfers, playing a crucial role in the accurate prediction of the lateral tire forces and their yaw moment contributions; 3) coupling between longitudinal and lateral tire forces, which has a significant influence on the front-to-rear distribution of the braking forces generated by the controller; and 4) nonlinear peak and stiffness factors of the tire model, with visible yet negligible effects on the results
Real-Time Capable Nonlinear Model Predictive Wheel Slip Control for Combined Driving and Cornering
No full textThis paper presents a traction controller for combined driving and cornering conditions, based on explicit nonlinear model predictive control. The prediction model includes a nonlinear tire force model using a simplified version of the Pacejka Magic Formula, incorporating the effect of combined longitudinal and lateral slips. Simulations of a front-wheel-drive electric vehicle with multiple motors highlight the benefits of the proposed formulation with respect to a controller with a tire model for pure longitudinal slip. Objective performance indicators provide a performance assessment in traction control scenarios
Trade restrictions with imported intermediate inputs : when does the trade balance improve?
No full textThe author's model demonstrates that when imports are predominantly intermediate inputs - as they are in most developing countries - import restrictions can not always be relied upon to improve the trade balance. Such restrictions act as a supply shock to the economy. Unless nontraded goods are intensive users of imported intermediaries, the general equilibrium consequence of import restrictions is a large enough reduction in export supplies to swamp the direct effect of the restrictions. The result is a deterioration of the trade balance.Environmental Economics&Policies,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Trade Policy,Rules of Origin
Title. A ' 0 LosAlamos PRELIMINARY RESULTS ON THE STABILITY OF SWITCHED POSITIVE LINEAR SYSTEMS
No full textAbstract-It was recently conjectured that the IIurwitz stability of a polytope of Metzler matrices is a necessary and sufficient condition for the stability of the associated switched linear system for arbitrary switching sequences. In this paper we show: (i) that this conjecture is true for a polytope constructed from a pair of second order Metzler matrices; (ii) that the conjecture is true for general polytopes of a finite number of second order Metzler matrices; and (iii) that the conjecture is in general false for higher order systems. The implications of our results, both for the design of switched positive linear systems, and for research directions that arise as a result of our work, are discussed toward the end of the paper
Language and immigration in Germany: the role of German language in recent immigration debates
No full textAll nations with significant dimensions of immigration and ethnic minorities are facing policy tensions stemming from two contradicting fundamental constitutional principles. The establishment and preservation of nationhood seems to require cultural homogeneity and associated integration of the population living on a specified territory. However, the aim of integration is challenged by the principle of recognising and safeguarding cultural identities of minorities and immigrants. One of central debates concerns language policy.This country study concerns the recent relation of language policy and immigration policy in Germany. It is based on the analysis of public discourses circling around the legislative process and the subsequent application and amendment of the foreigners’ statute of 1997 and the immigration statute of 2004 including the Green card initiative (2000) and the debate about restrictive policies after the Madrid bombing (2004). It also contains a case study of the controversies on the German-only policy on the playground of a multi-ethnic school in Wedding, a district of Berlin. Recent media coverage shows that this example, picked in 2006, has since achieved a paradigmatic quality.The thesis outlines and applies aspects of critical discourse analysis for the interpretation of selected relevant texts, mainly contained in national quality newspapers. The case study is also based on interviews and use of correspondence addressed to the school
Another View of the J-Curve
No full textWe use a two-good dynamic optimizing small open economy model to provide a new explanation of the J-Curve phenomenon in terms of habit persistence in consumption and sluggishness in capital adjustment. The results differ markedly depending on the permanence or temporary nature of the relative price change. A short-lived terms of trade worsening may lead to a once-for-all decrease in the marginal utility of wealth and to higher steady-state values of the habitual standard of living, the real expense, and the net foreign assets through the combination of intertemporal speculation, inertia, and hysteresis effects. Investment and real expense folow non-monotonic transitional paths and current account dynamics are driven by new forces. In accordance with recent empirical results, investment is procyclical, trade balance deteriorates initially, net foreign assets adjustment exhibits a J-Curve, and the current account surplus phase is associated with a fall in real income.Current account; Habit Formation; Temporary Shock; J-Curve
- …
