39,049 research outputs found
Preservation and conservation decisions in the local library
For a period of years, I have been aware that the decisions regarding
preservation which I have made, which I have shared in making, or which
have been made by others have not all been of the same nature. The level or
levels within the library's staff hierarchy of the persons involved make
some decisions differ from other decisions; however, these levels of involvement
are not the heart of the problem. The thing lacking was a clear way to
designate other distinctions which seemed necessary in attempting to
analyze such problems and decisions. I found little help in my reading or
sharing experiences with others in attempting to work in this area. In
reading the proceedings of the 1976 conference on A National Preservation
Program at the Library of Congress, I was therefore quite interested to
discover that Daniel Boorstin in opening the conference suggested a division
of the questions comprising the problem of preservation. He characterized
two rather distinct types of problems as epistemological and
technical. He further described the epistemological questions as being
social questions, meaning that they are questions relating to the interests
of those who will use, administer, and service the materials comprising the
collections. I must admit that the term epistemological sent me to the
dictionary because it has been some time since I had studied formal
philosophical language. At this point, it becomes necessary to understand
Boorstin's exact meaning and intention in interjecting this term into the
vocabulary of library preservation. Epistemology is defined as "the study
of the methods and grounds of knowledge especially with reference to its
limits and validity; broadly: the theory of knowledge."published or submitted for publicatio
A research program to reduce interior noise in general aviation airplanes
The relevance of KU-FRL test results in predicting (theoretically or semi-empirically) interior noise levels in general aviation aircraft was studied. As a result of this study, it was decided to make a few additions to the program. These additions are: (1) to use three (instead of two) noise sources in the plane wave tube to evaluate the influence of excitation spectrum on panel response, (2) to use theoretical and experimental data obtained in the course of the project to develop more efficient noise reduction materials (or procedures to apply these), or to develop guidelines for the design of such materials for procedures, and (3) to use nonstructural materials in the collection of specimens to be tested in the KU-FRL plane wave tube
Is the Galactic bulge devoid of planets?
Considering a sample of 31 exoplanetary systems detected by gravitational
microlensing, we investigate whether or not the estimated distances to these
systems conform to the Galactic distribution of planets expected from models.
We derive the expected distribution of distances and relative proper motions
from a simulated microlensing survey, correcting for the dominant selection
effects that affect the planet detection sensitivity as a function of distance,
and compare it to the observed distribution using Anderson-Darling (AD)
hypothesis testing. Taking the relative abundance of planets in the bulge to
that in the disk, , as a model parameter, we find that our model
is only consistent with the observed distribution for (for
a -value threshold of 0.01) implying that the bulge may be devoid of planets
relative to the disk. Allowing for a dependence of planet abundance on
metallicity and host mass, or an additional dependence of planet sensitivity on
event timescale does not restore consistency for . We examine
the distance estimates of some events in detail, and conclude that some
parallax-based distance estimates could be significantly in error. Only by
combining the removal of one problematic event from our sample and the
inclusion of strong dependences of planet abundance or detection sensitivity on
host mass, metallicity and event timescale are we able to find consistency with
the hypothesis that the bulge and disk have equal planet abundance.Comment: Revised following referee's report. 12 pages, 7 figures, 1 tabl
Digital matched filters for detecting Gaussian signals in Gaussian noise
Digital filters for detecting random signals in random nois
Grid generation strategies for turbomachinery configurations
Turbomachinery flow fields involve unique grid generation issues due to their geometrical and physical characteristics. Several strategic approaches are discussed to generate quality grids. The grid quality is further enhanced through blending and adapting. Grid blending smooths the grids locally through averaging and diffusion operators. Grid adaptation redistributes the grid points based on a grid quality assessment. These methods are demonstrated with several examples
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