19,785 research outputs found
Positional estimation techniques for an autonomous mobile robot
Techniques for positional estimation of a mobile robot navigation in an indoor environment are described. A comprehensive review of the various positional estimation techniques studied in the literature is first presented. The techniques are divided into four different types and each of them is discussed briefly. Two different kinds of environments are considered for positional estimation; mountainous natural terrain and an urban, man-made environment with polyhedral buildings. In both cases, the robot is assumed to be equipped with single visual camera that can be panned and tilted and also a 3-D description (world model) of the environment is given. Such a description could be obtained from a stereo pair of aerial images or from the architectural plans of the buildings. Techniques for positional estimation using the camera input and the world model are presented
Event anisotropy in 4.2A GeV/c C+C collisions
The directed and elliptic flow of protons and negative pions in 4.2A GeV/c
C+C collisions is studied using the Fourier analysis of azimuthal
distributions. It is found that the protons exhibit pronounced directed flow,
while the flow of pions is either non existent or too weak to be detected
experimentally. Also, it is found that in the entire rapidity interval the
elliptic flow is very small if not zero. These results are confirmed by the
Quark-Gluon-String Model (QGSM) and the relativistic transport model (ART 1.0),
except that these models predict very weak antiflow of pions. The more detailed
comparison with the QGSM suggests that the decay of resonances and rescattering
of secondaries dominantly determine the proton and negative pion flow at this
energy.Comment: 7 pages, 3 figures, TeX file changed from double to single-spacin
On fixed linear systems with a generalized performance criteria
Fixed linear systems with generalized performance criteri
Extending local features with contextual information in graph kernels
Graph kernels are usually defined in terms of simpler kernels over local
substructures of the original graphs. Different kernels consider different
types of substructures. However, in some cases they have similar predictive
performances, probably because the substructures can be interpreted as
approximations of the subgraphs they induce. In this paper, we propose to
associate to each feature a piece of information about the context in which the
feature appears in the graph. A substructure appearing in two different graphs
will match only if it appears with the same context in both graphs. We propose
a kernel based on this idea that considers trees as substructures, and where
the contexts are features too. The kernel is inspired from the framework in
[6], even if it is not part of it. We give an efficient algorithm for computing
the kernel and show promising results on real-world graph classification
datasets.Comment: To appear in ICONIP 201
Investigation of high p events in Nucleus-Nucleus collisions using the Hijing event generator
In recent years lot of interest has been observed in the nucleus-nucleus
collisions at RHIC energies in phenomena related to high physics
\cite{ref1}. The suppression of high particles and disappearance of
back-to-back jets compared to the scaling with number of binary nucleon-nucleon
collisions indicates that a nearly perfect liquid is produced in these
collisions. Results on self shadowing of high events are presented
using hadron multiplicity associated to high and unbiased events in
nucleus-nucleus collisions \cite{ref2} obtained from the hijing event
generator.Comment: 4 pages, 3 figures, Proceedings of the poster presented at Quark
Matter 200
Comparative Outcomes of Resident vs Attending Performed Surgery: A Systematic Review and Meta-Analysis
OBJECTIVE: To determine whether outcomes are different when surgery is performed by resident or attending surgeons, and which variables may affect outcomes. DESIGN: MEDLINE, EMBASE, and the Cochrane Library were searched from inception to May 2014 alongside the bibliographies of all included or relevant studies. Any study comparing outcomes from surgery performed by resident vs attending surgeons was eligible for inclusion. The main outcome measures were surgical complications (classified by Clavien-Dindo grade), death, operative time, and length of stay. Data were extracted independently by 2 authors and analyzed using the random-effects model. RESULTS: The final analysis included 182 eligible studies that enrolled 141 555 patients. Resident performed surgery took longer by 10.2 minutes (95% confidence interval (CI): 8.38-11.95), and had more Clavien-Dindo grade 1 (rate ratio = 1.14, 95% CI: 1.02-1.29) and grade 3a complications (rate ratio = 1.22, 95% CI: 1.04-1.44). Resident performed surgery resulted in fewer deaths (risk ratio = 0.83, 95% CI: 0.70-0.999) with a shorter length of stay of -0.49 days (95% CI: -0.77 to -0.21). Significant heterogeneity was present in 7 of 10 outcomes, which persisted during multiple subgroup analyses. CONCLUSIONS: Resident performed surgery appears to be safe in carefully selected patients. The significant amount of heterogeneity present in the study outcomes prevents generalizability of these results to specific clinical contexts
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