319 research outputs found
Implementation and testing of a CAM postprocessor for an industrial redundant workcell with evaluation of several fuzzified Redundancy Resolution Schemes
This paper describes the implementation of a postprocessor to adapt the toolpath generated by a CAM system (NXTM) to a complex workcell of eight joints (namely, a KUKA KR15/2 manipulator mounted on a linear track and synchronized with a rotary table), devoted to the rapid prototyping of 3D CAD-defined products. Previously, it evaluates several Redundancy Resolution Schemes at the joint-rate level for the configuration of the postprocessor, dealing not only with the additional joints but also with the redundancy due to the symmetry on the milling tool. The use of these redundancies is optimized by adjusting two performance criterion vectors related to both singularity avoidance and maintenance of a preferred reference posture, as secondary tasks to be done during the path tracking. In addition, two proper fuzzy inference engines actively adjust the weight of each joint in these tasks. The postprocessor is validated in a real prototyping of a Valencian Falla.This research is partially supported by the Technical University of Valencia (PAID-00-09), project PROMETEO 2009/063 of Generalitat Valenciana and research project DPI2009-14744-C03-01 of the Spanish Government.Andrés De La Esperanza, FJ.; Gracia Calandin, LI.; Tornero Montserrat, J. (2012). Implementation and testing of a CAM postprocessor for an industrial redundant workcell with evaluation of several fuzzified Redundancy Resolution Schemes. Robotics and Computer-Integrated Manufacturing. 28(2):265-274. https://doi.org/10.1016/j.rcim.2011.09.008S26527428
Insurance-Based Differences in Time to Diagnostic Follow-up after Positive Screening Mammography
Insurance may lengthen or inhibit time to follow-up after positive screening mammography. We assessed the association between insurance status and time to initial diagnostic follow-up after a positive screening mammogram
Flash-lag chimeras: the role of perceived alignment in the composite face effect
Spatial alignment of different face halves results in a configuration that mars the recognition of the identity of either face half (). What would happen to the recognition performance for face halves that were aligned on the retina but were perceived as misaligned, or were misaligned on the retina but were perceived as aligned? We used the 'flash-lag' effect () to address these questions. We created chimeras consisting of a stationary top half-face initially aligned with a moving bottom half-face. Flash-lag chimeras were better recognized than their stationary counterparts. However when flashed face halves were presented physically ahead of moving halves thereby nulling the flash-lag effect, recognition was impaired. This counters the notion that relative movement between the two face halves per se is sufficient to explain better recognition of flash-lag chimeras. Thus, the perceived spatial alignment of face halves (despite retinal misalignment) impairs recognition, while perceived misalignment (despite retinal alignment) does not
Bayesian fitting of Taurus brown dwarf spectral energy distributions
We present derived stellar and disc parameters for a sample of Taurus brown
dwarfs both with and without evidence of an associated disc. These parameters
have been derived using an online fitting tool
(http://bd-server.astro.ex.ac.uk/), which includes a statistically robust
derivation of uncertainties, an indication of pa- rameter degeneracies, and a
complete treatment of the input photometric and spectroscopic observations. The
observations of the Taurus members with indications of disc presence have been
fitted using a grid of theoretical models including detailed treatments of
physical processes accepted for higher mass stars, such as dust sublimation,
and a simple treatment of the accretion flux. This grid of models has been
designed to test the validity of the adopted physical mechanisms, but we have
also constructed models using parameterisation, for example semi-empirical dust
sublimation radii, for users solely interested in parameter derivation and the
quality of the fit. The parameters derived for the naked and disc brown dwarf
systems are largely consistent with literature observations. However, our inner
disc edge locations are consistently closer to the star than previous results
and we also derive elevated accretion rates over non-SED based accretion rate
derivations. For inner edge locations we attribute these differences to the
detailed modelling we have performed of the disc structure, particularly at the
crucial inner edge where departures in geometry from the often adopted vertical
wall due to dust sublimation (and therefore accretion flux) can compensate for
temperature (and therefore distance) changes to the inner edge of the dust
disc. In the case of the elevated derived accretion rates, in some cases, this
may be caused by the intrinsic stellar luminosities of the targets exceeding
that predicted by the isochrones we have adopted.Comment: The paper contains 35 pages with 15 figures and 17 tables. Accepted
for publication in MNRA
- …