3,395 research outputs found
Realising formal groups
We show that a large class of formal groups can be realised functorially by
even periodic ring spectra. The main advance is in the construction of
morphisms, not of objects.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol3/agt-3-8.abs.htm
Common subbundles and intersections of divisors
Let V_0 and V_1 be complex vector bundles over a space X. We use the theory
of divisors on formal groups to give obstructions in generalised cohomology
that vanish when V_0 and V_1 can be embedded in a bundle U in such a way that
V_0\cap V_1 has dimension at least k everywhere. We study various algebraic
universal examples related to this question, and show that they arise from the
generalised cohomology of corresponding topological universal examples. This
extends and reinterprets earlier work on degeneracy classes in ordinary
cohomology or intersection theory.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-42.abs.htm
Complex cobordism of involutions
We give a simple and explicit presentation of the Z/2-equivariant complex
cobordism ring.Comment: Published by Geometry and Topology at
http://www.maths.warwick.ac.uk/gt/GTVol5/paper11.abs.htm
The Self-Directed Goal Theory Experiment: A Mixed Methods Study of Personal Development Goal-Setting Programs and Self-Efficacy
Andragogy is not dead; it may be simply lying dormant until its essential component, self-directed learning, revives it again. The fact is that self-directed learning can be formal or informal. This mixed methods study explored the informal side of self-directed learning, concentrating on self-help (a popularized form of personal development goalsetting). Despite a thriving self-help market, several personal development goal-setting programs focus more on goal achievement, little on goal planning, and even less on the individual. A comparative analysis of autonomous, guided, and self-directed personal goal-setting programs determined if self-directedness maximizes self-efficacy. Additionally, the researcher’s original Self-Directed Goal Theory and an extensive review of previous literature further investigated what role (if any) adult education, demographics, goal characteristics, self-regulation, personal development areas, goal timing, self-monitoring, locus of control, motivation, cognition, and virtue cultivation plays in self-efficacy enhancement and overall goal success
Second life battery energy storage systems:converter topology and redundancy selection
Battery energy storage systems have traditionally been manufactured using new batteries with a good reliability. The high cost of such a system has led to investigations of using second life transportation batteries to provide an alternative energy storage capability. However, the reliability and performance of these batteries is unclear and multi-modular power electronics with redundancy have been suggested as a means of helping with this issue. This paper reviews work already undertaken on battery failure rate to suggest suitable figures for use in reliability calculations. The paper then uses reliability analysis and a numerical example to investigate six different multi-modular topologies and suggests how the number of series battery strings and power electronic module redundancy should be determined for the lowest hardware cost using a numerical example. The results reveal that the cascaded dc-side modular with single inverter is the lowest cost solution for a range of battery failure rates
Scalable iterative methods for sampling from massive Gaussian random vectors
Sampling from Gaussian Markov random fields (GMRFs), that is multivariate
Gaussian ran- dom vectors that are parameterised by the inverse of their
covariance matrix, is a fundamental problem in computational statistics. In
this paper, we show how we can exploit arbitrarily accu- rate approximations to
a GMRF to speed up Krylov subspace sampling methods. We also show that these
methods can be used when computing the normalising constant of a large
multivariate Gaussian distribution, which is needed for both any
likelihood-based inference method. The method we derive is also applicable to
other structured Gaussian random vectors and, in particu- lar, we show that
when the precision matrix is a perturbation of a (block) circulant matrix, it
is still possible to derive O(n log n) sampling schemes.Comment: 17 Pages, 4 Figure
Identification of individual enzymes in crude extracts by acrylamide gel electrophoresis
Identification of enzymes by acrylamide gel electrophoresi
An approach to the synthesis of biological tissue
Mathematical phantoms developed to synthesize realistic complex backgrounds such as those obtained when imaging biological tissue, play a key role in the quantitative assessment of image quality for medical and biomedical imaging. We present a modeling framework for the synthesis of realistic tissue samples. The technique is demonstrated using radiological breast tissue. The model employs a two-component image decomposition consisting of a slowly, spatially varying mean-background and a residual texture image. Each component is synthesized independently. The approach and results presented here constitute an important step towards developing methods for the quantitative assessment of image quality in medical and biomedical imaging, and more generally image science
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