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Transformation Leads (transformation + lead)
Selected AbstractsOn the use of high-order finite-difference discretization for LES with double decomposition of the subgrid-scale stressesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2008J. Meyers Abstract Large eddy simulation (LES) with additional filtering of the non-linear term, also coined LES with double decomposition of the subgrid-scale stress, is considered. In the literature, this approach is mainly encountered in combination with pseudo-spectral discretization methods. In this case, the additional filter is a sharp cut-off filter, which appears in the eventual computational algorithm as the 2/3-dealiasing procedure. In the present paper, the LES approach with additional filtering of the non-linear term is evaluated in a spatial, finite-difference discretization approach. The sharp cut-off filter used in pseudo-spectral methods is then replaced by a ,spectral-like' filter, which is formulated and discretized in physical space. As suggested in the literature, the filter width , of this spectral-like filter corresponds at least to 3/2 times the grid spacing h to avoid aliasing. Furthermore, spectral-like discretization of the derivatives are constructed such that derivative-discretization errors are low in the wavenumber range resolved by the filter, i.e. 0,kh,2,/3. The resulting method in combination with a Smagorinsky model is tested for decaying homogeneous isotropic turbulence and compared to standard lower-order discretization methods. Further, an analysis is elaborated of the Galilean-invariance problem, which arises when LES in double decomposition approach is combined with filters, which do not correspond to an orthogonal projection. The effects of a Galilean coordinate transformation on LES results, are identified in simulations, and we demonstrate that a Galilean transformation leads to wavenumber-dependent shifts of the energy spectra. Copyright © 2007 John Wiley & Sons, Ltd. [source] Time Deformation, Continuous Euler Processes and ForecastingJOURNAL OF TIME SERIES ANALYSIS, Issue 6 2006Chu-Ping C. Vijverberg Abstract., A continuous Euler model has time-varying coefficients. Through a logarithmic time transformation, a continuous Euler model can be transformed to a continuous autoregressive (AR) model. By using the continuous Kalman filtering through the Laplace method, this article explores the data application of a continuous Euler process. This time deformation of an Euler process deforms specific time-variant (non-stationary) behaviour to time-invariant (stationary) data on the deformed time scale. With these time-invariant data on the transformed time scale, one may use traditional tools to conduct parameter estimation and forecasts. The obtained results can then be transformed back to the original time scale. Simulated data and actual data such as bat echolocation and the US residential investment growth are used to demonstrate the usefulness of time deformation in forecasting. The results indicate that fitting a traditional autoregressive moving-average (ARMA) model on an Euler data set without imposing time transformation leads to forecasts that are out of phase while the forecasts of an Euler model stay mostly in phase. [source] James Fodor's Christian Theory of Truth: Is it Christian?THE HEYTHROP JOURNAL, Issue 4 2000Richard Davis The ,task confronting contemporary theology', says James Fodor, ,is that of the rehabilitation or recovery of a distinctively Christian vision of truth' (Christian Hermeneutics[Oxford, 1995] p. 72). In this paper I examine Fodor's attempt to construct a Christian or transformational theory of truth. I argue that his analysis of truth in terms of transformation leads to a concept of truth which is both subjective and relative. I argue further that Fodor's truth theory is either committed to a version of creative anti-realism, according to which the existence of basic structure of the world is determined by our linguistic activities, or it implies that although our language doesn't correspond to the world, we should go on making our theological truth claims anyway. I conclude that Fodor's Christian theory of truth is in most crucial respects not Christian at all. [source] Can ,market transformation' lead to ,sustainable business'?BUSINESS STRATEGY AND THE ENVIRONMENT, Issue 2 2004A critical appraisal of the UK's strategy for sustainable business This paper traces the origins and development of the concept of ,market transformation', from its beginnings as a part of energy policy in the USA, to its subsequent development in the UK. It discusses whether it could become a strategic option for British business in pursuit of sustainable growth. Drawing together themes from the academic literature on marketing, consumer behaviour, business, and energy policy, together with data from national programmes, and British government sources, the paper argues that such an approach would be based on a twin false premise , that selling energy efficiency to consumers is in accordance with modern marketing thinking, and that it has much to do with achieving sustainable development. It concludes that while achieving sustainable development will certainly encompass the transformation of markets for many products, ,market transformation' itself cannot be seen as a key driver for change. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment. [source] | ||||||||||