5,358 research outputs found
Online Convex Optimization with Binary Constraints
We consider online optimization with binary decision variables and convex
loss functions. We design a new algorithm, binary online gradient descent
(bOGD) and bound its expected dynamic regret. We provide a regret bound that
holds for any time horizon and a specialized bound for finite time horizons.
First, we present the regret as the sum of the relaxed, continuous round
optimum tracking error and the rounding error of our update in which the former
asymptomatically decreases with time under certain conditions. Then, we derive
a finite-time bound that is sublinear in time and linear in the cumulative
variation of the relaxed, continuous round optima. We apply bOGD to demand
response with thermostatically controlled loads, in which binary constraints
model discrete on/off settings. We also model uncertainty and varying load
availability, which depend on temperature deadbands, lockout of cooling units
and manual overrides. We test the performance of bOGD in several simulations
based on demand response. The simulations corroborate that the use of
randomization in bOGD does not significantly degrade performance while making
the problem more tractable
An artificial neural network system to identify alleles in reference electropherograms
© 2017 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
This author accepted manuscript is made available following 12 month embargo from date of publication (July 2017) in accordance with the publisher’s archiving policyElectropherograms are produced in great numbers in forensic DNA laboratories as part of everyday criminal casework. Before the results of these electropherograms can be used they must be scrutinised by analysts to determine what the identified data tells them about the underlying DNA sequences and what is purely an artefact of the DNA profiling process. This process of interpreting the electropherograms can be time consuming and is prone to subjective differences between analysts. Recently it was demonstrated that artificial neural networks could be used to classify information within an electropherogram as allelic (i.e. representative of a DNA fragment present in the DNA extract) or as one of several different categories of artefactual fluorescence that arise as a result of generating an electropherogram. We extend that work here to demonstrate a series of algorithms and artificial neural networks that can be used to identify peaks on an electropherogram and classify them. We demonstrate the functioning of the system on several profiles and compare the results to a leading commercial DNA profile reading system
Optimally Scheduling Public Safety Power Shutoffs
In an effort to reduce power system-caused wildfires, utilities carry out
public safety power shutoffs (PSPS) in which portions of the grid are
de-energized to mitigate the risk of ignition. The decision to call a PSPS must
balance reducing ignition risks and the negative impact of service
interruptions. In this work, we consider three PSPS scheduling scenarios, which
we model as dynamic programs. In the first two scenarios, we assume that N
PSPSs are budgeted as part of the investment strategy. In the first scenario, a
penalty is incurred for each PSPS declared past the Nth event. In the second,
we assume that some costs can be recovered if the number of PSPSs is below
while still being subject to a penalty if above N. In the third, the system
operator wants to minimize the number of PSPS such that the total expected cost
is below a threshold. We provide optimal or asymptotically optimal policies for
each case, the first two of which have closed-form expressions. Lastly, we
establish the applicability of the first PSPS model's policy to critical-peak
pricing, and obtain an optimal scheduling policy to reduce the peak demand
based on weather observations
Structure in the Rotation Measure Sky
An analysis of structure in rotation measure (RM) across the sky based on the
RM catalog of Taylor et al. (2009) is presented. Several resolved RM structures
are identified with structure in the local ISM, including radio loops I, II,
and III, the Gum nebula, and the Orion-Eridanus super bubble. Structure
functions (SFs) of RM are presented for selected areas, and maps of SF
amplitude and slope across the sky are compared with H-alpha intensity and
diffuse polarized intensity. RM variance on an angular scale of 1 degree is
correlated with length of the line of sight through the Galaxy, with a
contribution from local structures. The slope of the SFs is less concentrated
to the Galactic plane and less correlated with length of the line of sight
through the Galaxy, suggesting a more local origin for RM structure on angular
scales ~ 10 degrees. The RM variance is a factor ~2 higher towards the SGP than
towards the NGP, reflecting a more wide-spread asymmetry between the northern
and southern Galactic hemispheres. Depolarization of diffuse Galactic
synchrotron emission at latitudes < 30 degrees can be explained largely by
Faraday dispersion related to small-scale variance in RM, but the errors allow
a significant contribution from differential Faraday rotation along the line of
sight.Comment: 13 pages, 14 figures. Figures 1-4 and 9-10 available as separate
files. Accepted for publication in the Astrophysical Journal A complete pdf
with all figures included is available at
http://www.ras.ucalgary.ca/~stil/Stil_2010_RM_structure.pd
The Life and Work of the anti-apartheid movement within the Church of Scotland from 1975 to 1985
This article analyses the impact of the Church of Scotland (CoS) magazine Life and Work on the Dutch Reformed Church and other individuals and bodies during the period 1975–1985. It does this through investigating the editor’s approach to South African affairs and the nature of contributions that he published. Significantly different views were expressed by those who had lengthy exposure to the South African context as missionaries of the CoS and ‘tourists’ (holiday makers, relatives of residents in South Africa and church visitors). As the period progressed, changing attitudes are discerned that came more and more into line with the anti-apartheid stance of the General Assembly expressed through its boards and committees
Design, analysis and test verification of advanced encapsulation systems, phase 2 program results
Optical, electrical isolation, thermal structural, structural deflection, and thermal tests are reported. The utility of the optical, series capacitance, and structural deflection models was verified
Sister chromatid telomere fusions, but not NHEJ-mediated inter-chromosomal telomere fusions, occur independently of DNA ligases 3 and 4
Telomeres shorten with each cell division and can ultimately become substrates for non-homologous end-joining repair, leading to large-scale genomic rearrangements of the kind frequently observed in human cancers. We have characterised over 1400 telomere fusion events at the single-molecule level, using a combination of high-throughput sequence analysis together with experimentally-induced telomeric double-stranded DNA breaks. We show that a single chromosomal dysfunctional telomere can fuse with diverse non-telomeric genomic loci, even in the presence of an otherwise stable genome, and that fusion predominates in coding regions. Fusion frequency was markedly increased in the absence of TP53 checkpoint control and significantly modulated by the cellular capacity for classical, versus alternative, non-homologous end joining (NHEJ). We observed a striking reduction in inter-chromosomal fusion events in cells lacking DNA ligase 4, in contrast to a remarkably consistent profile of intra-chromosomal fusion in the context of multiple genetic knockouts, including DNA ligase 3 and 4 double-knockouts. We reveal distinct mutational signatures associated with classical NHEJ-mediated inter-chromosomal, as opposed to alternative NHEJ-mediated intra-chromosomal telomere fusions and evidence an unanticipated sufficiency of DNA ligase 1 for these intra-chromosomal events. Our findings have implications for mechanisms driving cancer genome evolution
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