5,731 research outputs found
A CLASS OF SEPARABILITY FLEXIBLE FUNCTIONAL FORMS
Quadratic flexible forms, such as the translog and generalized Leontief, are separability inflexible. That is, separability restrictions render them inflexible with regard to separable structures. A class functional forms is proposed that is flexible with regard to general production structures and remains flexible regarding weakly separable structures when separability restrictions are imposed, thus permitting tests of the separability hypothesis. Additionally, the restricted forms are parsimonious; that is they contain the minimum number of parameters with which flexibility can be achieved.Research Methods/ Statistical Methods,
MIT LMFBR blanket research project. Quarterly progress report, July 1, 1975--September 30, 1975
Research progress on physics experiments and calculations for LMFBR breeding blankets is briefly reported. (JWR
Herdís & Ólína: The Poetry of Everyday Life
The twin sisters Herdís Andrésdóttir and Ólína Andrésdóttir were born on the island Flatey in Breiðafjörður, western Iceland, in 1858. Following the death of their father at sea three years later, the family was dispersed and the sisters did not see each other until half a century later, when they were reunited in Reykjavík. In the intervening years both sisters had become well known as capable verse-makers in the traditional style, but it had never, it seems, occurred to them to write any of their poems down, let alone publish them. They were encouraged by friends to do so, and in 1924 they brought out a collection of their verse, entitled simply Ljóðmæli (Poems). Their poetry was highly traditional both in its form, which principally made use of rímur and ballad metres, and in terms of its subject matter, dealing with nature, reflections on life’s joys and sorrows and so on. Ólína, like her cousin Theodóra Thoroddsen, also contributed to the revival of the þula, a form of poetry traditionally associated with children. The book sold well, and a second edition, with some additional poems, came out in 1930. A third edition was brought out in 1976, long after their deaths, containing much new material; this edition has since been reprinted twice. Critical reception was overwhelmingly favourable, both in the learned and more popular press. Though somewhat at odds with the literary establishment of the day, they nevertheless had several powerful supporters among the literary and intellectual élite, foremost among them professor Sigurður Nordal. Despite having been “world-famous in Iceland” in their old age, Herdís and Ólína are little known today, and their work – much of it very fine indeed – has yet to receive the scholarly attention it deserves
Strong Pinning Enhancement in MgB2 Using Very Small Dy2O3 Additions
0.5 to 5.0 wt.% Dy2O3 was in-situ reacted with Mg + B to form pinned MgB2.
While Tc remained largely unchanged, Jc was strongly enhanced. The best sample
(only 0.5 wt.% Dy2O3) had a Jc of 6.5 x 10^5 A/cm^2 at 6K, 1T and 3.5 x 10^5
A/cm^2 at 20K, 1T, around a factor of 4 higher compared to the pure sample, and
equivalent to hot-pressed or nano-Si added MgB2 at below 1T. Even distributions
of nano-scale precipitates of DyB4 and MgO were observed within the grains. The
room temperature resistivity decreased with Dy2O3 indicative of improved grain
connectivity.Comment: 13 pages, 4 figures and 1 tabl
An assessment of internal blankets for gas-cooled fast reactors
Originally presented as first author's thesis (Ph. D.--Massachusetts Institute of Technology), 1980Includes bibliographical references (pages 338-346)Sponsored by General Atomic Compan
Fast Dynamic Graph Algorithms for Parameterized Problems
Fully dynamic graph is a data structure that (1) supports edge insertions and
deletions and (2) answers problem specific queries. The time complexity of (1)
and (2) are referred to as the update time and the query time respectively.
There are many researches on dynamic graphs whose update time and query time
are , that is, sublinear in the graph size. However, almost all such
researches are for problems in P. In this paper, we investigate dynamic graphs
for NP-hard problems exploiting the notion of fixed parameter tractability
(FPT).
We give dynamic graphs for Vertex Cover and Cluster Vertex Deletion
parameterized by the solution size . These dynamic graphs achieve almost the
best possible update time and the query time
, where is the time complexity of any static
graph algorithm for the problems. We obtain these results by dynamically
maintaining an approximate solution which can be used to construct a small
problem kernel. Exploiting the dynamic graph for Cluster Vertex Deletion, as a
corollary, we obtain a quasilinear-time (polynomial) kernelization algorithm
for Cluster Vertex Deletion. Until now, only quadratic time kernelization
algorithms are known for this problem.
We also give a dynamic graph for Chromatic Number parameterized by the
solution size of Cluster Vertex Deletion, and a dynamic graph for
bounded-degree Feedback Vertex Set parameterized by the solution size. Assuming
the parameter is a constant, each dynamic graph can be updated in
time and can compute a solution in time. These results are obtained by
another approach.Comment: SWAT 2014 to appea
Thin-Film Trilayer Manganate Junctions
Spin-dependent conductance across a manganate-barrier-manganate junction has
recently been demonstrated. The junction is a LaSrMnO%
-SrTiO-La SrMnO trilayer device supporting
current-perpendicular transport. Large magnetoresistance of up to a factor of
five change was observed in these junctions at 4.2K in a relatively low field
of the order of 100 Oe. Temperature and bias dependent studies revealed a
complex junction interface structure whose materials physics has yet to be
understood.Comment: 20 pages, 14 figures. To appear in Phil. Trans. R. Soc. Lond. A
vol.356 (1998
Public Lands
A contribution by Howard J. Bromberg to the Encyclopedia of Global Resources
Range Queries on Uncertain Data
Given a set of uncertain points on the real line, each represented by
its one-dimensional probability density function, we consider the problem of
building data structures on to answer range queries of the following three
types for any query interval : (1) top- query: find the point in that
lies in with the highest probability, (2) top- query: given any integer
as part of the query, return the points in that lie in
with the highest probabilities, and (3) threshold query: given any threshold
as part of the query, return all points of that lie in with
probabilities at least . We present data structures for these range
queries with linear or nearly linear space and efficient query time.Comment: 26 pages. A preliminary version of this paper appeared in ISAAC 2014.
In this full version, we also present solutions to the most general case of
the problem (i.e., the histogram bounded case), which were left as open
problems in the preliminary versio
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