Noise suppressing sensor encoding and neural signal orthonormalization

In this paper we regard first the situation where parallel channels are disturbed by noise. With the goal of maximal information conservation we deduce the conditions for a transform which "immunizes" the channels against noise influence before the signals are used in later operations. It shows up that the signals have to be decorrelated and normalized by the filter which corresponds for the case of one channel to the classical result of Shannon. Additional simulations for image encoding and decoding show that this constitutes an efficient approach for noise suppression. Furthermore, by a corresponding objective function we deduce the stochastic and deterministic learning rules for a neural network that implements the data orthonormalization. In comparison with other already existing normalization networks our network shows approximately the same in the stochastic case but, by its generic deduction ensures the convergence and enables the use as independent building block in other contexts, e.g. whitening for independent component analysis. Keywords: information conservation, whitening filter, data orthonormalization network, image encoding, noise suppression

DD-Dimensional Gravity from (D+1)(D+1) Dimensions

We generalise Wesson's procedure, whereby vacuum $(4+1)-$dimensional field equations give rise to $(3+1)-$dimensional equations with sources, to arbitrary dimensions. We then employ this generalisation to relate the usual $(3+1)-$dimensional vacuum field equations to $(2+1)-$dimensional field equations with sources and derive the analogues of the classes of solutions obtained by Ponce de Leon. This way of viewing lower dimensional gravity theories can be of importance in establishing a relationship between such theories and the usual 4-dimensional general relativity, as well as giving a way of producing exact solutions in $(2+1)$ dimensions that are naturally related to the vacuum $(3+1)-$dimensional solutions. An outcome of this correspondence, regarding the nature of lower dimensional gravity, is that the intuitions obtained in $(3+1)$ dimensions may not be automatically transportable to lower dimensions. We also extend a number of physically motivated solutions studied by Wesson and Ponce de Leon to $(D+1)$ dimensions and employ the equivalence between the $(D+1)$ Kaluza-Klein theories with empty $D-$dimensional Brans-Dicke theories (with $\omega=0$) to throw some light on the solutions derived by these authors.Comment: 11 pages, latex, published in CQG vol. 12 no. 1

Geld und âventiure: Narrative Aspekte der Zeit-Raum-Erfahrung bei Heinrich Kaufringer

The medieval ›Märe‹ is known for its special ›Typik‹ and so far no particular attention has been paid to the prevalence and effects of time and space in the texts. This article focuses on the narration and perception of time- and space-arrangements in texts of Heinrich Kaufringer. In view of how Kaufringer acts as a narrative director giving time and space a special integrative function, his cyclic texts ›Die Suche nach dem glücklichen Ehepaar‹ and ›Drei listige Frauen‹ are discussed in detail. Interestingly, a narrative strategy of synchronization and poetic compression creates multifaceted possibilities of actions here that could be happening whereas the common strategy of didactic narration seems to become less important. These results could contribute to a better understanding of the effects and possible intentions of choosing time- and space-settings and especially narrating simultaneity in medieval literatur

Sizing Analysis for Aircraft Utilizing Hybrid-Electronic Propulsion Systems

A submerged inlet investigation, using flow control in the form of discrete blowing, examined proximity and jet directionality to improve compressor face uniformity. The flow control locations were at the head of the ramp and part way down the ramp, providing four configurations under examination. Laser Doppler velocimetry (LDV)measurements at the throat determined the effect of the flow control based on the statistical velocity measurements. Blowing at closer proximity to the throat and targeting the largest velocity deficit region provided the best results. The airspeed and inlet velocity simulated takeoff and landing conditions; velocities ranged from Mach 0.1-0.3 at the throat. Secondary components and turbulence measurements proved useful in determining the effect of the flow control configurations. In a complimentary study, two serpentine ducts of rectangular cross-section evaluated the LDV capability before the inlet examination. The s-shaped serpentine ducts had features comparable to those expected in the submerged inlet. The flow through two serpentine ducts, of identical hydraulic diameters but different aspect ratios, demonstrated different behaviors despite all other features being the same. Two strong counter-rotating streamwise vortices formed for the 2:1 aspect ratio while four weaker vortices formed in the 1:2 aspect ratio duct. Computational simulations, performed on the serpentine ducts using a Reynolds shear stress model on a 4 million cell grid, agreed with the results of the experimental examination. The agreement between the exit profiles provided confidence in the LDV system to make the inlet measurements possible