54,397 research outputs found
Vision-based toddler tracking at home
This paper presents a vision-based toddler tracking system for detecting risk factors of a toddler's fall within the home environment. The risk factors have environmental and behavioral aspects and the research in this paper focuses on the behavioral aspects. Apart from common image processing tasks such as background subtraction, the vision-based toddler tracking involves human classification, acquisition of motion and position information, and handling of regional merges and splits. The human classification is based on dynamic motion vectors of the human body. The center of mass of each contour is detected and connected with the closest center of mass in the next frame to obtain position, speed, and directional information. This tracking system is further enhanced by dealing with regional merges and splits due to multiple object occlusions. In order to identify the merges and splits, two directional detections of closest region centers are conducted between every two successive frames. Merges and splits of a single object due to errors in the background subtraction are also handled. The tracking algorithms have been developed, implemented and tested
A smart vision sensor for detecting risk factors of a toddler's fall in a home environment
This paper presents a smart vision sensor for detecting risk factors of a toddler's fall in an indoor home environment assisting parents' supervision to prevent fall injuries. We identified the risk factors by analyzing real fall injury stories and referring to a related organization's suggestions to prevent falls. In order to detect the risk factors using computer vision, two major image processing methods, clutter detection and toddler tracking, were studied with using only one commercial web-camera. For practical purposes, there is no need for a toddler to wear any sensors or markers. The algorithms for detection have been developed, implemented and tested
Semileptonic Decay Scalar Form Factor and from Lattice QCD
We present a new study of D semileptonic decays on the lattice which employs
the Highly Improved Staggered Quark (HISQ) action for both the charm and the
light valence quarks. We work with MILC unquenched lattices and
determine the scalar form factor for
semileptonic decays. The form factor is obtained from a scalar current matrix
element that does not require any operator matching. We develop a new approach
to carrying out chiral/continuum extrapolations of . The method uses
the kinematic "" variable instead of or the kaon energy and is
applicable over the entire physical range. We find in the chiral plus
continuum limit and hereby improve the theory error on this quantity by a
factor of 4 compared to previous lattice determinations. Combining the
new theory result with recent experimental measurements of the product from BaBar and CLEO-c leads to the most
precise direct determination of the CKM matrix element to date,
, where the first error comes from experiment and the
second is the lattice QCD theory error. We calculate the ratio and find GeV and show
that this agrees with experiment.Comment: 23 pages, 31 figures, 11 tables. Added a paragraph in sction VII, and
updated with PDG 2010 instead of PDG 200
Meson and Baryon dispersion relations with Brillouin fermions
We study the dispersion relations of mesons and baryons built from Brillouin
quarks on one N_f=2 gauge ensemble provided by QCDSF. For quark masses up to
the physical strange quark mass, there is hardly any improvement over the
Wilson discretization, if either action is link-smeared and tree-level clover
improved. For quark masses in the range of the physical charm quark mass, the
Brillouin action still shows a perfect relativistic behavior, while the Wilson
action induces severe cut-off effects. As an application we determine the
masses of the \Omega_c^0, \Omega_{cc}^+ and \Omega_{ccc}^{++} baryons on that
ensemble.Comment: 16 pages, 9 figures, 4 tables; v2: one Reference added, matches
published versio
Automatic and ironic behavior are both mediated by changes in the self-concept
Recent accounts suggest that prime-to-behavior effects are mediated by changes to the active self-concept. Likewise, recent reports of post-suppression behavioral rebound have attributed changes to behavior to changes in the self-concept. According to such accounts, whenever an activated trait or stereotype can be easily incorporated into the active self, behavioral assimilation (i.e., behavior consistent with the activated concept) is likely to ensue. Yet, little evidence has emerged to directly support the mediating role of changes to the self-concept. The present research was designed to examine whether changes to the active self-concept are responsible for changes in behavior following stereotype suppression and priming. Participants who suppressed or were primed with stereotypes of the elderly were more likely to endorse stereotypic traits as self-descriptive and to behave in stereotypic ways. Critically, the former effect significantly mediated the latter. Implications for theories of concept activation and behavior are discussed. (C) 2011 Elsevier Inc. All rights reserved
Exact Convex Relaxation of Optimal Power Flow in Tree Networks
The optimal power flow (OPF) problem seeks to control power generation/demand
to optimize certain objectives such as minimizing the generation cost or power
loss in the network. It is becoming increasingly important for distribution
networks, which are tree networks, due to the emergence of distributed
generation and controllable loads. In this paper, we study the OPF problem in
tree networks. The OPF problem is nonconvex. We prove that after a "small"
modification to the OPF problem, its global optimum can be recovered via a
second-order cone programming (SOCP) relaxation, under a "mild" condition that
can be checked apriori. Empirical studies justify that the modification to OPF
is "small" and that the "mild" condition holds for the IEEE 13-bus distribution
network and two real-world networks with high penetration of distributed
generation.Comment: 22 pages, 7 figure
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