7,934 research outputs found
Determined to die! Ability to act following multiple self-inflicted gunshot wounds to the head. The cook county office of medical examiner experience (2005-2012) and review of literature
Cases of multiple (considered 2+) self-inflicted gunshot wounds are a rarity and require careful examination of the scene of
occurrence; thorough consideration of the decedentâs psychiatric, medical, and social histories; and accurate postmortem documentation of the
gunshot wounds. We present a series of four cases of multiple self-inflicted gunshot wounds to the head from the Cook County Medical Examinerâs
Office between 2005 and 2012 including the first case report of suicide involving eight gunshot wounds to the head. In addition, a
review of the literature concerning multiple self-inflicted gunshot wounds to the head is performed. The majority of reported cases document
two gunshot entrance wound defects. Temporal regions are the most common affected regions (especially the right and left temples). Determining
the capability to act following a gunshot wound to the head is necessary in crime scene reconstruction and in differentiation between homicide
and suicide
Minimum Cuts in Near-Linear Time
We significantly improve known time bounds for solving the minimum cut
problem on undirected graphs. We use a ``semi-duality'' between minimum cuts
and maximum spanning tree packings combined with our previously developed
random sampling techniques. We give a randomized algorithm that finds a minimum
cut in an m-edge, n-vertex graph with high probability in O(m log^3 n) time. We
also give a simpler randomized algorithm that finds all minimum cuts with high
probability in O(n^2 log n) time. This variant has an optimal RNC
parallelization. Both variants improve on the previous best time bound of O(n^2
log^3 n). Other applications of the tree-packing approach are new, nearly tight
bounds on the number of near minimum cuts a graph may have and a new data
structure for representing them in a space-efficient manner
Temperature-Induced Shape Memory Characteristics of Epoxy Resin-Based Fabric-Reinforced Composites
Shape memory characteristics of woven glass and carbon fiber fabric reinforced epoxy resin-based composites were assessed in bending mode using a dynamic mechanical analyzer. The reinforcement strongly improved the recovery stress but impaired the bending deformability. Composites with asymmetric fabric lay-up showed better performance when the reinforced section experienced local tension than compression during flexural loading
Shape memory performance of asymmetrically reinforced epoxy/carbon fibre fabric composites in flexure
In this study asymmetrically reinforced epoxy (EP)/carbon fibre (CF) fabric composites were prepared and their shape memory properties were quantified in both unconstrained and fully constrained flexural tests performed in a dynamic mechanical analyser (DMA). Asymmetric layering was achieved by incorporating two and four CF fabric layers whereby setting a resin- and reinforcement-rich layer ratio of 1/4 and 1/2, respectively. The recovery stress was markedly increased with increasing CF content. The related stress was always higher when the CF-rich layer experienced tension load locally. Specimens with CF-rich layers on the tension side yielded better shape fixity ratio, than those with reinforcement layering on the compression side. Cyclic unconstrained shape memory tests were also run up to five cycles on specimens having the CF-rich layer under local tension. This resulted in marginal changes in the shape fixity and recovery ratios
Linear-Time Poisson-Disk Patterns
We present an algorithm for generating Poisson-disc patterns taking O(N) time
to generate points. The method is based on a grid of regions which can
contain no more than one point in the final pattern, and uses an explicit model
of point arrival times under a uniform Poisson process.Comment: 4 pages, 2 figure
Approximate Graph Coloring by Semidefinite Programming
We consider the problem of coloring k-colorable graphs with the fewest
possible colors. We present a randomized polynomial time algorithm that colors
a 3-colorable graph on vertices with min O(Delta^{1/3} log^{1/2} Delta log
n), O(n^{1/4} log^{1/2} n) colors where Delta is the maximum degree of any
vertex. Besides giving the best known approximation ratio in terms of n, this
marks the first non-trivial approximation result as a function of the maximum
degree Delta. This result can be generalized to k-colorable graphs to obtain a
coloring using min O(Delta^{1-2/k} log^{1/2} Delta log n), O(n^{1-3/(k+1)}
log^{1/2} n) colors. Our results are inspired by the recent work of Goemans and
Williamson who used an algorithm for semidefinite optimization problems, which
generalize linear programs, to obtain improved approximations for the MAX CUT
and MAX 2-SAT problems. An intriguing outcome of our work is a duality
relationship established between the value of the optimum solution to our
semidefinite program and the Lovasz theta-function. We show lower bounds on the
gap between the optimum solution of our semidefinite program and the actual
chromatic number; by duality this also demonstrates interesting new facts about
the theta-function
Does Confidence Reporting from the Crowd Benefit Crowdsourcing Performance?
We explore the design of an effective crowdsourcing system for an -ary
classification task. Crowd workers complete simple binary microtasks whose
results are aggregated to give the final classification decision. We consider
the scenario where the workers have a reject option so that they are allowed to
skip microtasks when they are unable to or choose not to respond to binary
microtasks. Additionally, the workers report quantized confidence levels when
they are able to submit definitive answers. We present an aggregation approach
using a weighted majority voting rule, where each worker's response is assigned
an optimized weight to maximize crowd's classification performance. We obtain a
couterintuitive result that the classification performance does not benefit
from workers reporting quantized confidence. Therefore, the crowdsourcing
system designer should employ the reject option without requiring confidence
reporting.Comment: 6 pages, 4 figures, SocialSens 2017. arXiv admin note: text overlap
with arXiv:1602.0057
Wicked Problems and Gnarly Results: Reflecting on Design and Evaluation Methods for Idiosyncratic Personal Information Management Tasks
This paper is a case study of an artifact design and evaluation process; it is a reflection on how right thinking about design methods may at times result in sub-optimal results. Our goal has been to assess our decision making process throughout the design and evaluation stages for a software prototype in order to consider where design methodology may need to be tuned to be more sensitive to the domain of practice, in this case software evaluation in personal information management. In particular, we reflect on design methods around (1) scale of prototype, (2) prototyping and design process, (3) study design, and (4) study population
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