5,603 research outputs found
The monic integer transfinite diameter
We study the problem of finding nonconstant monic integer polynomials,
normalized by their degree, with small supremum on an interval I. The monic
integer transfinite diameter t_M(I) is defined as the infimum of all such
supremums. We show that if I has length 1 then t_M(I) = 1/2.
We make three general conjectures relating to the value of t_M(I) for
intervals I of length less that 4. We also conjecture a value for t_M([0, b])
where 0 < b < 1. We give some partial results, as well as computational
evidence, to support these conjectures.
We define two functions that measure properties of the lengths of intervals I
with t_M(I) on either side of t. Upper and lower bounds are given for these
functions.
We also consider the problem of determining t_M(I) when I is a Farey
interval. We prove that a conjecture of Borwein, Pinner and Pritsker concerning
this value is true for an infinite family of Farey intervals.Comment: 32 pages, 5 figure
Preliminary Candidate Advanced Avionics System (PCAAS)
Specifications which define the system functional requirements, the subsystem and interface needs, and other requirements such as maintainability, modularity, and reliability are summarized. A design definition of all required avionics functions and a system risk analysis are presented
27.5  W/m2 collection efficiency solar laser using a diffuse scattering cooling liquid:erratum
Indicators of Sustainability for Production and Biodiversity Conservation in Australian Rangelands
Identification and characterization of a homozygous deletion found in ovarian ascites by representational difference analysis
Coupled and separable iterations in nonlinear estimation
This thesis deals with algorithms to fit certain statistical
models. We are concerned with the interplay between the numerical
properties of the algorithm and the statistical properties of the
model fitted.
Chapter 1 outlines some results, concerning the construction of
tests and the convergence of algorithms, based on quadratic
approximations to the likelihood surface. These include the relationship
between statistical curvature and the convergence of the scoring
algorithm, separable regression, and a Gauss-Seidel process which we
called coupled iterations.
Chapters 2, 3 and 4 are concerned with varying parameter models.
Chapter 2 proposes an extension of generalized linear models by
including a linear predictor for (a function of) the dispersion
parameter also. Chapter 3 deals with various ways to go outside this
extended generalized linear model framework for normally distributed
data. Chapter 4 briefly describes how coupled iterations may be
applied to autoregressive and multinormal models.
Chapters 5 to 8 apply a generalization of Prony's classical
parametrization to solve separable regression problems which satisfy
a linear homogeneous difference equation. Chapter 5 introduces the
problem, specifies the assumptions under which asymptotic results are
proved, and shows that the reduced normal equations may be expressed
as a nonlinear eigenproblem in terms of the Prony parameters. Chapter
6 describes the algorithm which results from solving the eigenproblem,
including some computational details. Chapter 7 proves that the
algorithm is asymptotically stable. Chapter 8 compares the
convergence of the algorithm with that of Gauss-Newton by way of
simulations
Aging of poled ferroelectric ceramics due to relaxation of random depolarization fields by space-charge accumulation near grain boundaries
Migration of charged point defects triggered by the local random
depolarization field is shown to plausibly explain aging of poled ferroelectric
ceramics providing reasonable time and acceptor concentration dependences of
the emerging internal bias field. The theory is based on the evaluation of the
energy of the local depolarization field caused by mismatch of the
polarizations of neighbor grains. The kinetics of charge migration assumes
presence of mobile oxygen vacancies in the material due to the intentional or
unintentional acceptor doping. Satisfactory agreement of the theory with
experiment on the Fe-doped lead zirconate titanate is demonstrated.Comment: theory and experiment, 22 pages, 3 figure
Measurements of nonlinear lensing in a semiconductor disk laser gain sample under optical pumping and using a resonant femtosecond probe laser
Analysis of United Kingdom Off-Highway Construction Machinery Market and Its Consumers Using New-Sales Data
The off-highway construction machinery market and its consumers have attracted minimal previous research. This study addresses that void by analyzing annual United Kingdom (UK) (volume/portfolio) new-sales data for the 10 most popular products within that market, 1990–2010 inclusive. Graphical, descriptive statistical, Pearson-correlational, autocorrelational, and elementary modeling are employed to identify contrasts in sales regarding (1) high- and low-volume items; (2) growth trends and significant recessionary effects on volumes; (3) a demand change point circa 1997, since when annual product portfolio has changed little; and (4) product associations in consumer demand. Significant association is demonstrated between demand and construction output, especially with the value of new housing. Subsequently, consumption of wheeled loaders is modeled using construction volume, and demand for mini and crawler excavators is modeled using new-housing data. Time series trends for these machinery types are presented and forecast through 2015. The primary contribution of this study is a deeper understanding of the UK new-machinery market and the predilections of its consumers over the last two decades (to present)
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