8,835 research outputs found
Note on islands in path-length sequences of binary trees
An earlier characterization of topologically ordered (lexicographic)
path-length sequences of binary trees is reformulated in terms of an
integrality condition on a scaled Kraft sum of certain subsequences (full
segments, or islands). The scaled Kraft sum is seen to count the set of
ancestors at a certain level of a set of topologically consecutive leaves is a
binary tree.Comment: 4 page
Part Detector Discovery in Deep Convolutional Neural Networks
Current fine-grained classification approaches often rely on a robust
localization of object parts to extract localized feature representations
suitable for discrimination. However, part localization is a challenging task
due to the large variation of appearance and pose. In this paper, we show how
pre-trained convolutional neural networks can be used for robust and efficient
object part discovery and localization without the necessity to actually train
the network on the current dataset. Our approach called "part detector
discovery" (PDD) is based on analyzing the gradient maps of the network outputs
and finding activation centers spatially related to annotated semantic parts or
bounding boxes.
This allows us not just to obtain excellent performance on the CUB200-2011
dataset, but in contrast to previous approaches also to perform detection and
bird classification jointly without requiring a given bounding box annotation
during testing and ground-truth parts during training. The code is available at
http://www.inf-cv.uni-jena.de/part_discovery and
https://github.com/cvjena/PartDetectorDisovery.Comment: Accepted for publication on Asian Conference on Computer Vision
(ACCV) 201
Fish-based groups for ecological assessment in rivers: the importance of environmental drivers on taxonomic and functional traits of fish Assemblages
The use of river-types is of practical value, serving as groups for which
assessment procedures can be developed and applied. An abiotic typology
was set by the Portuguese Water Agency, mainly based on 6 major
morphoclimatic regions. However, to be biologically meaningful, this typology
should fit the distribution patterns of the biological quality elements
communities proposed in Water Framework Directive under the lowest
possible human pressure. This study aimed to identify and characterize
fish-based geographical groups for continental Portugal and their environmental
and geographical discriptors, using taxonomic and functional
traits. Sampling took place between 2004 and 2006 during Spring. Fish
fauna from 155 reference sites was analysed using a multivariate
approach. Cluster Analysis on fish composition identified 10 fish-groups,
expressing a clear correspondence to the river basin level, due to the
restrict basin distribution of many species. Groups showed a wider aggregation
in 4 regions with a larger geographical correspondence, statistically
supported by Similarity Analysis, both on fish composition and mostly on
fish metrics/guilds. Principal Components Analysis revealed major environmental
drivers associated to fish-groups and fish-regions. Fish-groups
were hierarchically grouped over major and local regions, expressing a
large-scale response to a North-South environmental gradient defined by
temperature, precipitation, mineralization and altitude, and a regional scale
response mainly to drainage area and flow discharge. From North to
South, fish-regions were related to the morphoclimatic regions. Results
contributed to reduce redundance in abiotic river-types and set the final
typology for Portuguese rivers, constituting a fundamental tool for planning
and managing water resources
Differential Effects of Fatigue on Movement Variability
When individuals perform purposeful actions to fatigue, there is typically a general decline in their movement performance. This study was designed to investigate the effects exercise-induced fatigue has on lower limb kinetics and kinematics during a side-step cutting task. In particular, it was of interest to determine what changes could be seen in mean amplitude and all metrics of signal variability with fatigue. The results of the study revealed that post-fatigue there was an overall decrease in absolute force production as reflected by a decline in mean amplitude and variability (SD) of the ground reaction forces (GRFV and GRFML). A decrease in mean and SD of the knee moments were also observed post-exercise. Interestingly, this trend was not mirrored by similar changes in time-dependent properties of these signals. Instead, there was an increase in the SampEn values (reflecting a more variable, irregular signal) for GRF force profiles, knee kinematics and moments following the exercise-induced fatigue. These results illustrate that fatigue can have differential effects on movement variability, resulting in a both an increase and decrease in movement variability, depending on the variable selected. Thus, the impact of fatigue is not simply restricted to a decline in force producing capacity of the system but more importantly it demonstrates that the ability of the person to perform a smooth and controlled action is limited due to fatigue
Hot Core, Outflows and Magnetic Fields in W43-MM1 (G30.79 FIR 10)
We present submillimeter spectral line and dust continuum polarization
observations of a remarkable hot core and multiple outflows in the high-mass
star-forming region W43-MM1 (G30.79 FIR 10), obtained using the Submillimeter
Array (SMA). A temperature of 400 K is estimated for the hot-core using
CHCN (J=19-18) lines, with detections of 11 K-ladder components. The high
temperature and the mass estimates for the outflows indicate high-mass
star-formation. The continuum polarization pattern shows an ordered
distribution, and its orientation over the main outflow appears aligned to the
outflow. The derived magnetic field indicates slightly super-critical
conditions. While the magnetic and outflow energies are comparable, the B-field
orientation appears to have changed from parsec scales to 0.1 pc scales
during the core/star-formation process.Comment: accepted, ApJ Letter
A new method for one-stage hepatectomy for dogs
A method is described for one-stage complete hepatectomy in dogs with preservation of the inferior vena cava. The method can be done rapidly with minimal blood loss and has a low operative mortality. The maximum survival time compares favorably with other methods of hepatectomy. © 1959
Instantons in the Double-Tensor Multiplet
The double-tensor multiplet naturally appears in type IIB superstring
compactifications on Calabi-Yau threefolds, and is dual to the universal
hypermultiplet. We revisit the calculation of instanton corrections to the
low-energy effective action, in the supergravity approximation. We derive a
Bogomolny'i bound for the double-tensor multiplet and find new instanton
solutions saturating the bound. They are characterized by the topological
charges and the asymptotic values of the scalar fields in the double-tensor
multiplet.Comment: 17 pages, LaTeX2e with amsmath.sty; v2: minor change
KINEMATICS ANALYSIS OF POLE VAULT DURING NATIONAL INDOOR ATHLETICS CHAMPIONSHIPS
There should be a minimal level of individual variation presented by athletes in high level competitions, reflecting a high degree of consistency in the form of execution. By registering and subsequently analysing kinematic and kinetic data, obtained during athletic exercises, it is possible to verify such differences. The objective of this work was to collect kinematic data in order to quantify and verify these differences. Parameters such as amplitude, frequency, velocity, inter-segmental angles and kinetic energy were quantified, in order to understand the variations found in the different parameters. One should assume that an athlete that presents major variations from the above-mentioned parameters is not at his or her best form. We analysed 16 exercises of 3 athletes in the Portugal Indoor Championship in the year of the Sydney Olympic Games. This analysis
enabled trainers to gain access to information on stability of technique in the exercise of each jump
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