173,332 research outputs found
Full operators and algebras generated by invertible operators
In the present work we characterized full operators and we showed some
properties that have nonfull injectives operators. With the results developed
for full operators, we affirmatively respond two questions formulated by Bravo
and Feintuch on when the inverse of an operator can be weakly approximated by
polynomials in the operatorComment: 5 page
E-book readers in higher education
Ebook readers have received a mixed press, with some hailing them as the future of reading and others believing that they will never be popular. The study outlined here aims to understand the attitudes of, and issues of importance to, lecturers in UK academia, with a view to improving the design of ebook readers for education in the future. An evaluation of five portable devices is presented, in which lecturers were given the opportunity to read an ebook and provide feedback via a questionnaire. Results are compared with concerns arising from other experiments in the same field, and recommendations are made for successful ebook design
Woody and arboreal habitats of the Green Salamander (Aneides aeneus) in the Blue Ridge Mountains
The green salamander (Aneides aeneus) is primarily considered a rock crevice dwelling species. However, many early observations from Kentucky, Tennessee, Virginia, and West Virginia report A. aeneus taken from woody and arboreal habitats. There have been only four published records of A. aeneus using such habitats within the Blue Ridge Disjunct population of southwest North Carolina, northeast Georgia, and northwest South Carolina, and no records since 1952. Here I report two personal observations of A. aeneus using arboreal habitats in North Carolina. Additionally, I report nine observations, made by others, of A. aeneus using woody, arboreal, or otherwise non-rock-crevice habitats in North and South Carolina, including the first non-rock-crevice A. aeneus nesting record for the Blue Ridge. I also speculate that woody and arboreal habitats play a much larger role in the life-history of A. aeneus than generally thought, and that the rarity of A. aeneus is linked to the loss of American Chestnut and old-growth forests
Improved Heterogeneous Distance Functions
Instance-based learning techniques typically handle continuous and linear
input values well, but often do not handle nominal input attributes
appropriately. The Value Difference Metric (VDM) was designed to find
reasonable distance values between nominal attribute values, but it largely
ignores continuous attributes, requiring discretization to map continuous
values into nominal values. This paper proposes three new heterogeneous
distance functions, called the Heterogeneous Value Difference Metric (HVDM),
the Interpolated Value Difference Metric (IVDM), and the Windowed Value
Difference Metric (WVDM). These new distance functions are designed to handle
applications with nominal attributes, continuous attributes, or both. In
experiments on 48 applications the new distance metrics achieve higher
classification accuracy on average than three previous distance functions on
those datasets that have both nominal and continuous attributes.Comment: See http://www.jair.org/ for an online appendix and other files
accompanying this articl
An analysis of Gipps' car-following model of highway traffic
A mathematical analysis of Gipps's (1981) car?following model is performed. This model is of practical importance as it powers the UK Transport Research Laboratory highway simulation package SISTM. Uniform flow solutions and a speed–headway function are derived under simplifying conditions. A linear stability analysis of uniform flow is then performed, and stable and unstable regimes are identified. Finally, some numerical simulations for a variety of parameter regimes are presented. <br/
Automatic pump Patent
Automatically reciprocating, high pressure pump for use in spacecraft cryogenic propellant
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