1,105 research outputs found
Learning Interpretable Spatial Operations in a Rich 3D Blocks World
In this paper, we study the problem of mapping natural language instructions
to complex spatial actions in a 3D blocks world. We first introduce a new
dataset that pairs complex 3D spatial operations to rich natural language
descriptions that require complex spatial and pragmatic interpretations such as
"mirroring", "twisting", and "balancing". This dataset, built on the simulation
environment of Bisk, Yuret, and Marcu (2016), attains language that is
significantly richer and more complex, while also doubling the size of the
original dataset in the 2D environment with 100 new world configurations and
250,000 tokens. In addition, we propose a new neural architecture that achieves
competitive results while automatically discovering an inventory of
interpretable spatial operations (Figure 5)Comment: AAAI 201
Multiple cyclotron line-forming regions in GX 301-2
We present two observations of the high-mass X-ray binary GX 301-2 with
NuSTAR, taken at different orbital phases and different luminosities. We find
that the continuum is well described by typical phenomenological models, like a
very strongly absorbed NPEX model. However, for a statistically acceptable
description of the hard X-ray spectrum we require two cyclotron resonant
scattering features (CRSF), one at ~35 keV and the other at ~50 keV. Even
though both features strongly overlap, the good resolution and sensitivity of
NuSTAR allows us to disentangle them at >=99.9% significance. This is the first
time that two CRSFs are seen in GX 301-2. We find that the CRSFs are very
likely independently formed, as their energies are not harmonically related
and, if it were a single line, the deviation from a Gaussian shape would be
very large. We compare our results to archival Suzaku data and find that our
model also provides a good fit to those data. We study the behavior of the
continuum as well as the CRSF parameters as function of pulse phase in seven
phase bins. We find that the energy of the 35 keV CRSF varies smoothly as
function of phase, between 30-38 keV. To explain this variation, we apply a
simple model of the accretion column, taking the altitude of the line-forming
region, the velocity of the in-falling material, and the resulting relativistic
effects into account. We find that in this model the observed energy variation
can be explained simply due to a variation of the projected velocity and
beaming factor of the line forming region towards us.Comment: 18 pages, 10 figures, accepted for publication in A&
Autofluorescence lifetime augmented reality as a means for real-time robotic surgery guidance in human patients.
Due to loss of tactile feedback the assessment of tumor margins during robotic surgery is based only on visual inspection, which is neither significantly sensitive nor specific. Here we demonstrate time-resolved fluorescence spectroscopy (TRFS) as a novel technique to complement the visual inspection of oral cancers during transoral robotic surgery (TORS) in real-time and without the need for exogenous contrast agents. TRFS enables identification of cancerous tissue by its distinct autofluorescence signature that is associated with the alteration of tissue structure and biochemical profile. A prototype TRFS instrument was integrated synergistically with the da Vinci Surgical robot and the combined system was validated in swine and human patients. Label-free and real-time assessment and visualization of tissue biochemical features during robotic surgery procedure, as demonstrated here, not only has the potential to improve the intraoperative decision making during TORS but also other robotic procedures without modification of conventional clinical protocols
Turbine Design and Analysis for the J-2X Engine Turbopumps
Pratt and Whitney Rocketdyne and NASA Marshall Space Flight Center are developing the advanced upper stage J-2X engine based on the legacy design of the J-2/J-2S family of engines which powered the Apollo missions. The cryogenic propellant turbopumps have been denoted as Mark72-F and Mark72-0 for the fuel and oxidizer side, respectively. Special attention is focused on preserving the essential flight-proven design features while adapting the design to the new turbopump configuration. Advanced 3-D CFD analysis has been employed to verify turbine aero performance at current flow regime boundary conditions and to mitigate risks associated with stresses. A limited amount of redesign and overall configuration modifications allow for a robust design with performance level matching or exceeding requirement
Lattice Models
In this paper I construct lattice models with an underlying
superalgebra symmetry. I find new solutions to the graded Yang-Baxter equation.
These {\it trigonometric} -matrices depend on {\it three} continuous
parameters, the spectral parameter, the deformation parameter and the
parameter, , of the superalgebra. It must be emphasized that the
parameter is generic and the parameter does not correspond to the
`nilpotency' parameter of \cite{gs}. The rational limits are given; they also
depend on the parameter and this dependence cannot be rescaled away. I
give the Bethe ansatz solution of the lattice models built from some of these
-matrices, while for other matrices, due to the particular nature of the
representation theory of , I conjecture the result. The parameter
appears as a continuous generalized spin. Finally I briefly discuss the problem
of finding the ground state of these models.Comment: 19 pages, plain LaTeX, no figures. Minor changes (version accepted
for publication
Assessment of I-125 seed implant accuracy when using the live-planning technique for low dose rate prostate brachytherapy
Extent: 9p.Background: Low risk prostate cancers are commonly treated with low dose rate (LDR) brachytherapy involving I-125 seeds. The implementation of a âlive-planningâ technique at the Royal Adelaide Hospital (RAH) in 2007 enabled the completion of the whole procedure (i.e. scanning, planning and implant) in one sitting. âLive-planningâ has the advantage of a more reliable delivery of the planned treatment compared to the âtraditional pre-planâ technique (where patient is scanned and planned in the weeks prior to implant). During live planning, the actual implanted needle positions are updated real-time on the treatment planning system and the dosimetry is automatically recalculated. The aim of this investigation was to assess the differences and clinical relevance between the planned dosimetry and the updated real-time implant dosimetry. Methods: A number of 162 patients were included in this dosimetric study. A paired t-test was performed on the D90, V100, V150 and V200 target parameters and the differences between the planned and implanted dose distributions were analysed. Similarly, dosimetric differences for the organs at risk (OAR) were also evaluated. Results: Small differences between the primary dosimetric parameters for the target were found. Still, the incidence of hotspots was increased with approximately 20% for V200. Statistically significant increases were observed in the doses delivered to the OAR between the planned and implanted data; however, these increases were consistently below 3% thus probably without clinical consequences. Conclusions: The current study assessed the accuracy of prostate implants with I-125 seeds when compared to initial plans. The results confirmed the precision of the implant technique which RAH has in place. Nevertheless, geographical misses, anatomical restrictions and needle displacements during implant can have repercussions for centres without live-planning option if dosimetric changes are not taken into consideration.Joshua Moorrees, John M Lawson and Loredana G Marc
Analogies, metaphors, and wondering about the future: Lay sense-making around synthetic meat
Drawing on social representations theory, we explore how the public make sense of the unfamiliar, taking as the example a novel technology: synthetic meat. Data from an online deliberation study and eighteen focus groups in Belgium, Portugal and the UK indicated that the various strategies of sense-making afforded different levels of critical thinking about synthetic meat. Anchoring to genetic modification, metaphors like âFrankenfoodsâ and commonplaces like âplaying Godâ closed off debates around potential applications of synthetic meat, whereas asking factual and rhetorical questions about it, weighing up pragmatically its risks and benefits, and envisaging changing current mentalities or behaviours in order to adapt to scientific developments enabled a consideration of synthetic meatâs possible implications for agriculture, environment, and society. We suggest that research on public understanding of technology should cultivate a climate of active thinking and should encourage questioning during the process of sense-making to try to reduce unhelpful anchoring
- âŠ