Development and modification of a digital program for final approach to landing

The development and implementation of a dynamic digital computer simulator which may be used to evaluate aircraft performance when operating under the control and guidance of various navigation, landing, and flight control systems are discussed. The digital computer program may be used to simulate and evaluate the relationships and interactions between various factors such as the microwave landing system, avionics receivers and onboard processors, aircraft aerodynamics, aircraft automatic control systems, control surfaces, and wind and other external effects. The models used to represent aircraft aerodynamics, control system and control surfaces; weather and wind effects; and the microwave landing system are described. Example results are presented for a simulation of a Boeing 737 using two sample control systems while subjected to various atmospheric conditions and microwave landing system errors. The limitations and performance capabilities of these control systems are discussed in terms of their ability to utilize the microwave landing system signal

Refinement and validation of two digital Microwave Landing System (MLS) theoretical models

Two digital microwave landing system theoretical models are considered which are generic models for the Doppler and scanning-beam frequency reference versions of the MLS. These models represent errors resulting from both system noise and discrete multipath. The data used for the validation effort were obtained from the Texas Instrument conventional scanning beam and the Hazeltine Doppler feasibility hardware versions of the MLS. Topics discussed include tape read software, time history plots, computation of power spectral density, smoothed power spectra, best-fit models, different equations for digital simulation, and discrete multipath errors

Zero Modes for the D=11 Membrane and Five-Brane

There exist extremal p-brane solutions of $D\!=\!11$ supergravity for p=2~and~5. In this paper we investigate the zero modes of the membrane and the five-brane solutions as a first step toward understanding the full quantum theory of these objects. It is found that both solutions possess the correct number of normalizable zero modes dictated by supersymmetry.Comment: Minor typos corrected, one reference added, agrees with published version. 9 RevTeX pages, 1 figure include

Vacuum interpolation in supergravity via super p-branes

We show that many of the recently proposed supersymmetric p-brane solutions of d=10 and d=11 supergravity have the property that they interpolate between Minkowski spacetime and a compactified spacetime, both being supersymmetric supergravity vacua. Our results imply that the effective worldvolume action for small fluctuations of the super p-brane is a supersingleton field theory for $(adS)_{p+2}$, as has been often conjectured in the past.Comment: 8p

Branes as BIons

A BIon may be defined as a finite energy solution of a non-linear field theory with distributional sources. By contrast a soliton is usually defined to have no sources. I show how harmonic coordinates map the exteriors of the topologically and causally non-trivial spacetimes of extreme p-branes to BIonic solutions of the Einstein equations in a topologically trivial spacetime in which the combined gravitational and matter energy momentum is located on distributional sources. As a consequence the tension of BPS p-branes is classically unrenormalized. The result holds equally for spacetimes with singularities and for those, like the M-5-brane, which are everywhere singularity free.Comment: Latex, 9 pages, no figure

Variational QMC study of a Hydrogen atom in jellium with comparison to LSDA and LSDA-SIC solutions

A Hydrogen atom immersed in a finite jellium sphere is solved using variational quantum Monte Carlo (VQMC). The same system is also solved using density functional theory (DFT), in both the local spin density (LSDA) and self-interaction correction (SIC) approximations. The immersion energies calculated using these methods, as functions of the background density of the jellium, are found to lie within 1eV of each other with minima in approximately the same positions. The DFT results show overbinding relative to the VQMC result. The immersion energies also suggest an improved performance of the SIC over the LSDA relative to the VQMC results. The atom-induced density is also calculated and shows a difference between the methods, with a more extended Friedel oscillation in the case of the VQMC result.Comment: 16 pages, 9 Postscript figure

The Finiteness Requirement for Six-Dimensional Euclidean Einstein Gravity

The finiteness requirement for Euclidean Einstein gravity is shown to be so stringent that only the flat metric is allowed. We examine counterterms in 4D and 6D Ricci-flat manifolds from general invariance arguments.Comment: 15 pages, Introduction is improved, many figures(eps

Scattering of Fermions off Dilaton Black Holes

We discuss how various properties of dilaton black holes depend on the dilaton coupling constant $a$. In particular we investigate the $a$-dependence of certain mass parameters both outside and in the extremal limit and discuss their relation to thermodynamical quantities. To further illuminate the role of the coupling constant $a$ we look at a massless point particle in a dilaton black hole geometry as well as the scattering of (neutral) fermions. In this latter case we find that the scattering potential vanishes for the zero angular momentum mode which seems to indicate a catastrophic deradiation when $a>1$.Comment: 12, Oslo-TP-4-94, USITP-94-