41,190 research outputs found
Two-phase, passive separator-and-filter assembly
Assembly separates liquid from gas by passive hydrophilic/hydrophobic material approach. Apparatus is comprised of porous glass hydrophilic tubes. Quantity, lateral size, and pore size of glass tubes are determined by particular design requirements with regard to water rate, water quality contamination level, application endurance life, and operating differential pressure level
Communities in Networks
We survey some of the concepts, methods, and applications of community
detection, which has become an increasingly important area of network science.
To help ease newcomers into the field, we provide a guide to available
methodology and open problems, and discuss why scientists from diverse
backgrounds are interested in these problems. As a running theme, we emphasize
the connections of community detection to problems in statistical physics and
computational optimization.Comment: survey/review article on community structure in networks; published
version is available at
http://people.maths.ox.ac.uk/~porterm/papers/comnotices.pd
Persistent homology of time-dependent functional networks constructed from coupled time series
We use topological data analysis to study "functional networks" that we
construct from time-series data from both experimental and synthetic sources.
We use persistent homology with a weight rank clique filtration to gain
insights into these functional networks, and we use persistence landscapes to
interpret our results. Our first example uses time-series output from networks
of coupled Kuramoto oscillators. Our second example consists of biological data
in the form of functional magnetic resonance imaging (fMRI) data that was
acquired from human subjects during a simple motor-learning task in which
subjects were monitored on three days in a five-day period. With these
examples, we demonstrate that (1) using persistent homology to study functional
networks provides fascinating insights into their properties and (2) the
position of the features in a filtration can sometimes play a more vital role
than persistence in the interpretation of topological features, even though
conventionally the latter is used to distinguish between signal and noise. We
find that persistent homology can detect differences in synchronization
patterns in our data sets over time, giving insight both on changes in
community structure in the networks and on increased synchronization between
brain regions that form loops in a functional network during motor learning.
For the motor-learning data, persistence landscapes also reveal that on average
the majority of changes in the network loops take place on the second of the
three days of the learning process.Comment: 17 pages (+3 pages in Supplementary Information), 11 figures in many
text (many with multiple parts) + others in SI, submitte
Control in the technical societies: a brief history
By the time control engineering emerged as a coherent body of knowledge and practice (during and just after WW2) professional engineering societies had existed for many decades. Since control engineering is an interdisciplinary branch of the profession, new sections devoted to control were quickly established within the various existing technical societies. In addition, some new bodies devoted specifically or primarily to control were established. This article, a revised version of a paper presented at the IEEE 2009 Conference on the History of Technical Societies, describes how control engineering as a distinct branch of engineering became represented in technical societies in a number of countries
Accounting for Seismic Risk in Financial Analysis of Property Investment
A methodology is presented for making property investment decisions using loss
analysis and the principles of decision analysis. It proposes that the investor choose among
competing investment alternatives on the basis of the certainty equivalent of their net asset value
which depends on the uncertain discounted future net income, uncertain discounted future
earthquake losses, initial equity and the investor’s risk tolerance. The earthquake losses are
modelled using a seismic vulnerability function, the site seismic hazard function, and an
assumption that strong shaking at a site follows a Poisson process. A building-specific
vulnerability approach, called assembly-based vulnerability, or ABV, is used. ABV involves a
simulation approach that includes dynamic structural analyses and damage analyses using
fragility functions and probability distributions on unit repair costs and downtimes for all
vulnerable structural and nonstructural components in a building. The methodology is
demonstrated using some results from a seven-storey reinforced-concrete hotel in Los Angeles
Community Structure in the United States House of Representatives
We investigate the networks of committee and subcommittee assignments in the
United States House of Representatives from the 101st--108th Congresses, with
the committees connected by ``interlocks'' or common membership. We examine the
community structure in these networks using several methods, revealing strong
links between certain committees as well as an intrinsic hierarchical structure
in the House as a whole. We identify structural changes, including additional
hierarchical levels and higher modularity, resulting from the 1994 election, in
which the Republican party earned majority status in the House for the first
time in more than forty years. We also combine our network approach with
analysis of roll call votes using singular value decomposition to uncover
correlations between the political and organizational structure of House
committees.Comment: 44 pages, 13 figures (some with multiple parts and most in color), 9
tables, to appear in Physica A; new figures and revised discussion (including
extra introductory material) for this versio
The Bowl Championship Series: A Mathematical Review
We discuss individual components of the college football Bowl Championship
Series, compare with a simple algorithm defined by random walks on a biased
graph, attempt to predict whether the proposed changes will truly lead to
increased BCS bowl access for non-BCS schools, and conclude by arguing that the
true problem with the BCS Standings lies not in the computer algorithms, but
rather in misguided addition.Comment: 12 pages, 2 figures, submitted to Notices of the AM
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