1,566 research outputs found
Geologic applications of thermal inertia image using HCMM data
The author has identified the following significant results. Comparison of a simulated HCMM image of the Pisgah Crater, California test site obtained from aircraft data with an image generated from the preliminary satellite data tape of the area indicates that the HCMM satellite data appears much as predicted by the simulation
Temporal and dimensional effects in evolutionary graph theory
The spread in time of a mutation through a population is studied analytically
and computationally in fully-connected networks and on spatial lattices. The
time, t_*, for a favourable mutation to dominate scales with population size N
as N^{(D+1)/D} in D-dimensional hypercubic lattices and as N ln N in
fully-connected graphs. It is shown that the surface of the interface between
mutants and non-mutants is crucial in predicting the dynamics of the system.
Network topology has a significant effect on the equilibrium fitness of a
simple population model incorporating multiple mutations and sexual
reproduction. Includes supplementary information.Comment: 6 pages, 4 figures Replaced after final round of peer revie
On -functions with bounded spectrum
We consider the class of functions in ,
whose Fourier transform has bounded support. We obtain a description of
continuous maps such that
for every function .
Only injective affine maps have this property
Golden Sands Of Waikiki : Song
https://digitalcommons.library.umaine.edu/mmb-vp/1527/thumbnail.jp
Multi-vehicle Control in a Strong Flowfield with Application to Hurricane Sampling
A major obstacle to path-planning and formation-control algorithms in multi-vehicle systems are strong flows in which the ambient flow speed is greater than the vehicle speed relative to the flow. This challenge is espe-cially pertinent in the application of unmanned aircraft used for collecting targeted observations in a hurricane. The presence of such a flowfield may inhibit a vehicle from making forward progress relative to a ground-fixed frame, thus limiting the directions in which it can travel. Using a self-propelled particle model in which each particle moves at constant speed relative to the flow, this paper presents results for motion coordination in a strong, known flowfield. We present the particle model with respect to inertial and rotating reference frames and provide for each case a set of con-ditions on the flowfield that ensure trajectory feasibility. Results from the Lyapunov-based design of decentralized control algorithms are presented for circular, folium, and spirograph trajectories, which are selected for their potential use as hurricane sampling trajectories. The theoretical results are illustrated using numerical simulations in an idealized hurricane model. Nomenclature N Number of particles in the system k Particle index k = 1,..., N rk Position of k th particle with respect to inertial frame r̃k Position of k th particle with respect to rotating fram
Conductance Phases in Aharonov-Bohm Ring Quantum Dots
The regimes of growing phases (for electron numbers N~0-8) that pass into
regions of self-returning phases (for N>8), found recently in quantum dot
conductances by the Weizmann group are accounted for by an elementary Green
function formalism, appropriate to an equi-spaced ladder structure (with at
least three rungs) of electronic levels in the quantum dot. The key features of
the theory are physically a dissipation rate that increases linearly with the
level number (and tentatively linked to coupling to longitudinal optical
phonons) and a set of Fano-like meta-stable levels, which disturb the
unitarity, and mathematically the change over of the position of the complex
transmission amplitude-zeros from the upper-half in the complex gap-voltage
plane to the lower half of that plane. The two regimes are identified with
(respectively) the Blaschke-term and the Kramers-Kronig integral term in the
theory of complex variables.Comment: 20 pages, 4 figure
- …