Optimal Inference in Regression Models with Nearly Integrated Regressors

This paper considers the problem of conducting inference on the regression coefficient in a bivariate regression model with a highly persistent regressor. Gaussian power envelopes are obtained for a class of testing procedures satisfying a conditionality restriction. In addition, the paper proposes feasible testing procedures that attain these Gaussian power envelopes whether or not the innovations of the regression model are normally distributed.

Optimal Inference in Regression Models with Nearly Integrated Regressors

This paper considers the problem of conducting inference on the regression coeffcient in a bivariate regression model with a highly persistent regressor. Gaussian power envelopes are obtained for a class of testing procedures satisfying a conditionality restriction. In addition, the paper proposes feasible testing procedures that attain these Gaussian power envelopes whether or not the innovations of the regression model are normally distributed.

ALTERNATIVE FUTURES OF RURAL AREAS IN THE EU: A COMPARATIVE ANALYSIS OF SCENARIO STUDIES

What does rural Europe look like in 2030? Is agriculture still the main land user? In recent years, studies such as ESPON, Eururalis, SCENAR2020, SENSOR, SEAMLESS and PRELUDE have tried to address these questions. These studies resulted in a number of alternative futures of rural areas in the EU. In this paper a comparative analysis of these scenario studies is made in order to explore differences and similarities in the scenarios and alternative futures of rural areas in the EU. For this purpose, we designed a scheme for assessing the properties of the various scenarios and a scheme for a systematic description of the rural futures according to the scenarios. It appears that most scenario studies use a baseline scenario and a set of alternative scenarios with different degrees of policy regulation. Agriculture will continue to be a main land user in 2030, although some land abandonment will take place.Rural Europe, scenario studies, alternative futures, land-use, territorial disparities, Agribusiness, Community/Rural/Urban Development, Research Methods/ Statistical Methods,

Time-resolved Adaptive Direct FEM Simulation of High-lift Aircraft Configurations

Our simulation methodology is referred to as Direct FEM Simulation (DFS), or General Galerkin (G2) and uses a finite element method (FEM) with piecewise linear approximation in space and time, and with numerical stabilization in the form of a weighted least squares method based on the residual. The incompressible Navier-Stokes Equations (NSE) are discretized directly, without applying any filter. Thus, the method does not result in Large Eddy Simulation (LES) filtered solutions, but is instead an approximation of a weak solution satisfying the weak form of the NSE. In G2 we have a posteriori error estimates for quantities of interest that can be expressed as functionals of a weak solution. These a posteriori error estimates, which form the basis for our adaptive mesh refinement algorithm, are based on the solution of an associated adjoint problem with a goal quantity (the aerodynamic forces in this work) as data, similarly to an optimal control problem. We provide references to related work below. The methodology and software have been previously validated for a number of turbulent flow benchmark problems, including one of the HiLiftPW-2 high Reynolds number cases. The DFS method is implemented in the Unicorn solver, which uses the open source software framework FEniCS-HPC, designed for automated solution of partial differential equations on massively parallel architectures using the FEM. In this chapter we present adaptive results from the Third AIAA High Lift Prediction Workshop in Denver, Colorado based on our DFS methodology and Unicorn/FEniCS-HPC software. We show that the methodology quantitavely and qualitatively captures the main features of the experiment - aerodynamic forces and the stall mechanism with a novel numerical tripping, with a much coarser mesh resolution and cheaper computational cost than the standard in the field

Out of Good Fortune: The Economics of Tragedy in the House of Atreus

This study will examine the linkages of money with power and justice in two tragedies centered upon the house of Atreus: Aeschylus’ Agamemnon and Euripides’ Electra. While at first glance, the house of Atreus seems to be plagued by a succession of murders motivated by revenge, its fate is marked by deep problems with the transactional, materialistic elements of society. Ultimately, the struggle for material resources at such great personal cost challenges deeply entrenched beliefs in Greek society. Aristocracy, seemingly founded upon noble principles, is actually centered upon such an unstable basis as money. Furthermore, the question of money illuminates the perilous position occupied by women. Equated with financial gain through marriage, their objectification in tragedy has terrible consequences. Traffic in women begins as a symbolic transaction meant to solidify homosocial bonds. The women of tragedy, however, speak frankly about the material nature of such exchanges and thus reveal the bare profit-and- loss accountancy of male society

Computability and Adaptivity in CFD

We give a brief introduction to research on adaptive computational methods for laminar compressible and incompressible flow, and then focus on computability and adaptivity for turbulent incompressible flow, where we present a framework for adaptive finite element methods with duality- based a posteriori error control for chosen output quantities of interest. We show in concrete examples that outputs such as mean values in time of drag and lift of a bluff body in a turbulent flow are computable to a tolerance of a few percent, for a simple geometry using some hundred thousand mesh points, and for complex geometries some million mesh points

New Theory of Flight

We present a new mathematical theory explaining the fluid mechanics of subsonic flight, which is fundamentally different from the existing boundary layer-circulation theory by Prandtl–Kutta–Zhukovsky formed 100 year ago. The new theory is based on our new resolution of d’Alembert’s paradox showing that slightly viscous bluff body flow can be viewed as zero-drag/lift potential flow modified by 3d rotational slip separation arising from a specific separation instability of potential flow, into turbulent flow with nonzero drag/lift. For a wing this separation mechanism maintains the large lift of potential flow generated at the leading edge at the price of small drag, resulting in a lift to drag quotient of size 15–20 for a small propeller plane at cruising speed with Reynolds number $Re \approx 10^7$ and a jumbojet at take-off and landing with $Re \approx 10^8$, which allows flight at affordable power. The new mathematical theory is supported by computed turbulent solutions of the Navier–Stokes equations with a slip boundary condition as a model of observed small skin friction of a turbulent boundary layer always arising for $Re > 10^6$, in close accordance with experimental observations over the entire range of angle of attacks including stall using a few millions of mesh points for a full wing-body configuration

Direct FEM computation of turbulent multiphase flow in 3D priting nozzle design

In this paper, we present a nozzle design of the 3D printing using FEniCS-HPC as mathematical and simulation tool. In recent years 3D printing or Additive Manufacturing (AM) has become a emerging technology and it has been already in use for many industries. 3D printing considered as a sustainable production or eco-friendly production, where one can minimize the wastage of the material during the production. Many industries are replacing their traditional parts or product manufacturing into optimized or smart 3D printing technology. In order to have 3D printing to be efficient, this should have optimized nozzle design. Here we design the nozzle for the titanium material. Since it is a metal during the process it has to be preserved by the inert gas. All this makes this problem comes under the multiphase flow. FEniCS-HPC is high level mathematical tool, where one can easily modify a mathematical equations according to the physics and has a good scalability on massively super computer architecture. And this problem modelled as Direct FEM/General Galerkin methodology for turbulent incompressible variable-density flow in FEniCS-HP