1,922 research outputs found
Flavour Democracy in Strong Unification
We show that the fermion mass spectrum may naturally be understood in terms
of flavour democratic fixed points in supersymmetric theories which have a
large domain of attraction in the presence of "strong unification". Our
approach provides an alternative to the approximate Yukawa texture zeroes of
the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken
gauged family symmetry which illustrates our approach.Comment: 21 Pages plain latex; includes 5 eps figure
Evaluating the Augmented Reality Human-Robot Collaboration System
This paper discusses an experimental comparison of three user interface techniques for interaction with a mobile robot located remotely from the user. A typical means of operating a robot in such a situation is to teleoperate the robot using visual cues from a camera that displays the robotâs view of its work environment. However, the operator often has a difficult time maintaining awareness of the robot in its surroundings due to this single ego-centric view. Hence, a multi-modal system has been developed that allows the remote human operator to view the robot in its work environment through an Augmented Reality (AR) interface. The operator is able to use spoken dialog, reach into the 3D graphic representation of the work environment and discuss the intended actions of the robot to create a true
collaboration. This study compares the typical ego-centric driven view to two versions of an AR interaction system for an
experiment remotely operating a simulated mobile robot. One
interface provides an immediate response from the remotely located robot. In contrast, the Augmented Reality Human-Robot Collaboration (AR-HRC) System interface enables the user to discuss and review a plan with the robot prior to execution. The AR-HRC interface was most effective, increasing accuracy by
30% with tighter variation, while reducing the number of close calls in operating the robot by factors of ~3x. It thus provides the means to maintain spatial awareness and give the users the feeling
they were working in a true collaborative environment
Collaborating with a Mobile Robot: An Augmented Reality Multimodal Interface
Invited paperWe have created an infrastructure that allows a human to collaborate in a natural manner with a robotic system. In this paper we describe our system and its implementation with a mobile robot. In our
prototype the human communicates with the mobile robot using natural speech and gestures, for example, by selecting a point in 3D space and saying âgo hereâ or âgo behind thatâ. The robot responds using
speech so the human is able to understand its intentions and beliefs. Augmented Reality (AR) technology is used to facilitate natural use of gestures and provide a common 3D spatial reference for both the robot and human, thus providing a means for grounding of communication and maintaining spatial awareness.
This paper first discusses related work then gives a brief overview of AR and its capabilities. The architectural design we have developed is outlined and then a case study is discussed
Quasinormal Modes Beyond Kerr
The quasinormal modes (QNMs) of a black hole spacetime are the free, decaying
oscillations of the spacetime, and are well understood in the case of Kerr
black holes. We discuss a method for computing the QNMs of spacetimes which are
slightly deformed from Kerr. We mention two example applications: the
parametric, turbulent instability of scalar fields on a background which
includes a gravitational QNM, and the shifts to the QNM frequencies of Kerr
when the black hole is weakly charged. This method may be of use in studies of
black holes which are deformed by external fields or are solutions to
alternative theories of gravity.Comment: Proceedings of the Sant Cugat Forum on Astrophysics (2014). Session
on 'Gravitational Wave Astrophysics.' 7 page
Letter from Henry Bidleman Bascom, A.L.P. Green & S.A. Latta to James B. Finley
Bascom, Green and Latta write representing the Methodist Episcopal Church South. They were appointed to serve as the Board of Commissioners to negotiate with a similar board of the M.E. Church concerning the division of property and funds, as laid out by the Plan of Separation (General Conference, 1844). The financial hardships faced by clergy, wives, widows, and retired clergy in the M.E.C. South are difficult to bear. The M.E.C. South board pleads with the M.E.C. board to schedule a meeting of the Joint Commissions as soon as possible to work out a final settlement. Abstract Number - 821https://digitalcommons.owu.edu/finley-letters/1306/thumbnail.jp
Associations between sole ulcer, white line disease and digital dermatitis and the milk yield of 1824 dairy cows on 30 dairy cow farms in England and Wales from February 2003âNovember 2004
The milk yields of 1824 cows were used to investigate the effect of lesion-specific causes of lameness, based on farmer treatment and diagnosis of lame cows, on milk yield. A three level hierarchical model of repeated test day yields within cows within herds was used to investigate the impact of lesion-specific causes of lameness (sole ulcer, white line disease, digital dermatitis and other causes) on milk yield before and after treatment compared with unaffected cows. Cattle which developed sole ulcer (SU) and white line disease (WLD) were higher yielding cattle before they were diagnosed. Their milk production fell to below that of the mean of unaffected cows before diagnosis and remained low after diagnosis. In cattle which developed digital dermatitis (DD) there was no significant difference in milk yield before treatment and a slightly raised milk yield immediately after treatment. The estimated milk loss attributable to SU and WLD was approximately 570kg and 370kg respectively. These results highlight that specific types of lameness vary by herds and within herds they are associated with higher yielding cattle. Consequently lesion-specific lameness reduction programmes targeting the cow and farm specific causes of lameness might be more effective than generic recommendations. They also highlight the importance of milk loss when estimating the economic impact of SU and WLD on the farms profitability
Coherent Photoproduction of eta-mesons on Three-Nucleon Systems
A microscopic few-body description of near-threshold coherent photoproduction
of the eta-meson on tritium and He3 targets is given. The photoproduction
cross-section is calculated using the Finite Rank Approximation (FRA) of the
nuclear Hamiltonian. The results indicate a strong final state interaction of
the eta-meson with the residual nucleus. Sensitivity of the results to the
choice of the eta-N T-matrix is investigated. The importance of obeying the
two-body unitarity condition in the eta-N system is demonstrated.Comment: 17 pages, RevTeX, 5 eps-figures, submitted to Phys. Rev.
Type II and heterotic one loop string effective actions in four dimensions
We analyze the reduction to four dimensions of the R^4 terms which are part
of the ten-dimensional string effective actions, both at tree level and one
loop. We show that there are two independent combinations of R^4 present, at
one loop, in the type IIA four dimensional effective action, which means they
both have their origin in M-theory. The d=4 heterotic effective action also has
such terms. This contradicts the common belief thathere is only one R^4 term in
four-dimensional supergravity theories, given by the square of the Bel-Robinson
tensor. In pure N=1 supergravity this new R^4 combination cannot be directly
supersymmetrized, but we show that, when coupled to a scalar chiral multiplet
(violating the U(1) -symmetry), it emerges in the action after elimination
of the auxiliary fields.Comment: v2: 22 pages. Discussion on the new R^4 term and extended
supergravity has been abridged and improved. Published versio
Do we know the mass of a black hole? Mass of some cosmological black hole models
Using a cosmological black hole model proposed recently, we have calculated
the quasi-local mass of a collapsing structure within a cosmological setting
due to different definitions put forward in the last decades to see how similar
or different they are. It has been shown that the mass within the horizon
follows the familiar Brown-York behavior. It increases, however, outside the
horizon again after a short decrease, in contrast to the Schwarzschild case.
Further away, near the void, outside the collapsed region, and where the
density reaches the background minimum, all the mass definitions roughly
coincide. They differ, however, substantially far from it. Generically, we are
faced with three different Brown-York mass maxima: near the horizon, around the
void between the overdensity region and the background, and another at
cosmological distances corresponding to the cosmological horizon. While the
latter two maxima are always present, the horizon mass maxima is absent before
the onset of the central singularity.Comment: 11 pages, 8 figures, revised version, accepted in General Relativity
and Gravitatio
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