Application of advanced on-board processing concepts to future satellite communications systems: Bibliography

Abstracts are presented of a literature survey of reports concerning the application of signal processing concepts. Approximately 300 references are included

Optimum predetection diversity receiving system Patent

Development of optimum pre-detection diversity combining receiving system adapted for use with amplitude modulation, phase modulation, and frequency modulation system

The use of x-ray scattering to study the anomalous elastic properties of fe-ni alloys

X-ray scattering technique for study of elastic properties of nickel-iron allo

Gravitational energy

Observers at rest in a stationary spacetime flat at infinity can measure small amounts of rest-mass+internal energies+kinetic energies+pressure energy in a small volume of fluid attached to a local inertial frame. The sum of these small amounts is the total "matter energy" for those observers. The total mass-energy minus the matter energy is the binding gravitational energy. Misner, Thorne and Wheeler evaluated the gravitational energy of a spherically symmetric static spacetime. Here we show how to calculate gravitational energy in any static and stationary spacetime for isolated sources with a set of observers at rest. The result of MTW is recovered and we find that electromagnetic and gravitational 3-covariant energy densities in conformastatic spacetimes are of opposite signs. Various examples suggest that gravitational energy is negative in spacetimes with special symmetries or when the energy-momentum tensor satisfies usual energy conditions.Comment: 12 pages. Accepted for publication in Class. Quantum Gra

Integral Constraints On cosmological Perturbations and their Energy

We show the relation between Traschen's integral equations and the energy, and ``position of the centre of mass'', of the matter perturbations in a Robertson-Walker spacetime. When the perturbations are ``localised'' we get a set of integral constraints that includes hers. We illustrate them on a simple example.Comment: 19 pages, Tex file, submitted to Classical and Quantum Gravit

Ubic: Bridging the gap between digital cryptography and the physical world

Advances in computing technology increasingly blur the boundary between the digital domain and the physical world. Although the research community has developed a large number of cryptographic primitives and has demonstrated their usability in all-digital communication, many of them have not yet made their way into the real world due to usability aspects. We aim to make another step towards a tighter integration of digital cryptography into real world interactions. We describe Ubic, a framework that allows users to bridge the gap between digital cryptography and the physical world. Ubic relies on head-mounted displays, like Google Glass, resource-friendly computer vision techniques as well as mathematically sound cryptographic primitives to provide users with better security and privacy guarantees. The framework covers key cryptographic primitives, such as secure identification, document verification using a novel secure physical document format, as well as content hiding. To make a contribution of practical value, we focused on making Ubic as simple, easily deployable, and user friendly as possible.Comment: In ESORICS 2014, volume 8712 of Lecture Notes in Computer Science, pp. 56-75, Wroclaw, Poland, September 7-11, 2014. Springer, Berlin, German

The growth of galaxies in cosmological simulations of structure formation

We use hydrodynamic simulations to examine how the baryonic components of galaxies are assembled, focusing on the relative importance of mergers and smooth accretion in the formation of ~L_* systems. In our primary simulation, which models a (50\hmpc)^3 comoving volume of a Lambda-dominated cold dark matter universe, the space density of objects at our (64-particle) baryon mass resolution threshold, M_c=5.4e10 M_sun, corresponds to that of observed galaxies with L~L_*/4. Galaxies above this threshold gain most of their mass by accretion rather than by mergers. At the redshift of peak mass growth, z~2, accretion dominates over merging by about 4:1. The mean accretion rate per galaxy declines from ~40 M_sun/yr at z=2 to ~10 M_sun/yr at z=0, while the merging rate peaks later (z~1) and declines more slowly, so by z=0 the ratio is about 2:1. We cannot distinguish truly smooth accretion from merging with objects below our mass resolution threshold, but extrapolating our measured mass spectrum of merging objects, dP/dM ~ M^a with a ~ -1, implies that sub-resolution mergers would add relatively little mass. The global star formation history in these simulations tracks the mass accretion rate rather than the merger rate. At low redshift, destruction of galaxies by mergers is approximately balanced by the growth of new systems, so the comoving space density of resolved galaxies stays nearly constant despite significant mass evolution at the galaxy-by-galaxy level. The predicted merger rate at z<~1 agrees with recent estimates from close pairs in the CFRS and CNOC2 redshift surveys.Comment: Submitted to ApJ, 35 pp including 15 fig

Improving customer satisfaction through the management of perceptions of waiting

Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1989.Includes bibliographical references (leaves 112-113).by Karen L. Katz and Blaire R. Martin.M.S

COBE Observations of the Microwave Counterparts of Gamma Ray Bursts

We have used the data from the COBE satellite to search for delayed microwave emission (31 - 90 GHz) from Gamma Ray Bursts (GRBs). The large $7^\circ$ beam of COBE is well matched to the large positional uncertainties in the GRB locations, although it also means that fluxes from (point source) GRB objects will be diluted. In view of this we are doing a statistical search of the GRBs which occurred during the currently released COBE DMR data (years 1990 and 1991), which overlap $\sim 200$ GRBs recorded by GRO. Here we concentrate on just the top 10 GRBs (in peak counts/second). We obtain the limits on the emission by comparing the COBE fluxes before and after the GRB at the GRB location. Since it is thought that the microwave emission should lag the GRB event, we have searched the GRB position for emission in the few months following the GRB occurrence.Comment: 5 pages, LaTE