426 research outputs found
Mitigation of Engine Inlet Distortion Through Adjoint-Based Design
The adjoint-based design capability in FUN3D is extended to allow efficient gradient- based optimization and design of concepts with highly integrated aero-propulsive systems. A circumferential distortion calculation, along with the derivatives needed to perform adjoint-based design, have been implemented in FUN3D. This newly implemented distortion calculation can be used not only for design but also to drive the existing mesh adaptation process and reduce the error associated with the fan distortion calculation. The design capability is demonstrated by the shape optimization of an in-house aircraft concept equipped with an aft fuselage propulsor. The optimization objective is the minimization of flow distortion at the aerodynamic interface plane of this aft fuselage propulsor
Combining interpolation and 3D level set method (I+3DLSM) for medical image segmentation
A combined interpolation - 3D Level Set Method (I+3DLSM) based segmentation process is presented. The performance in terms of accuracy of the 3-dimensional (3D) level set method (LSM) in the segmentation of throat regions from highly anisotropic magnetic resonance imaging (MRI) volumes, with and without an interpolation step is evaluated. Qualitative and quantitative results from real MRI data suggest that performing interpolation, to reconstruct isotropic MRI volumes, prior to 3D LSM improves the accuracy of the segmentation results, compared to interpolation post 3D LSM and no interpolation at all
Validation of a magnetic resonance imaging-based auto-contouring software tool for gross tumour delineation in head and neck cancer radiotheraphy planning
To perform statistical validation of a newly developed magnetic resonance imaging (MRI) auto-contouring software tool for gross tumour volume (GTV) delineation in head and neck tumours to assist in radiotherapy planning. Axial MRI baseline scans were obtained for 10 oropharyngeal and laryngeal cancer patients. GTV was present on 102 axial slices and auto-contoured using the modified fuzzy c-means clustering integrated with level set method (FCLSM). Peer reviewed (C-gold) manual contours were used as the reference standard to validate auto-contoured GTVs (C-auto) and mean manual contours (C-manual) from 2 expert clinicians (C1 and C2). Multiple geometrical metrics, including Dice Similarity Coefficient (DSC) were used for quantitative validation. A DSC ≥0.7 was deemed acceptable. Inter-and intra-variabilities amongst the manual contours were also validated. The 2-dimension (2D) contours were then reconstructed in 3D for GTV volume calculation, comparison and 3D visualisation. The mean DSC between C-gold and C-auto was 0.79. The mean DSC bet ween C-gold and C-manual was 0.79 and that between C1 and C2 was 0.80. The average time for GTV auto-contouring per patient was 8 minutes (range 6-13mins; mean 45seconds per axial slice) compared to 15 minutes (range 6-23mins; mean 88 seconds per axial slice) for C1. The average volume concordance between C-gold and C-auto volumes was 86. 51% compared to 74.16% between C-gold and C-manual. The average volume concordance between C1 and C2 volumes was 86.82%. This newly-designed MRI-based auto-contouring software tool shows initial acceptable results in GTV delineation of oropharyngeal and laryngeal tumours using FCLSM. This auto-contouring software tool may help reduce inter-and intra- variability and can assist clinical oncologists with time-consuming, complex radiotherapy planning
Incorporating next-to-leading order matrix elements for hadronic diboson production in showering event generators
A method for incorporating information from next-to-leading order QCD matrix
elements for hadronic diboson production into showering event generators is
presented. In the hard central region (high jet transverse momentum) where
perturbative QCD is reliable, events are sampled according to the first order
tree level matrix element. In the soft and collinear regions next-to-leading
order corrections are approximated by calculating the differential cross
section across the phase space accessible to the parton shower using the first
order (virtual graphs included) matrix element. The parton shower then provides
an all-orders exclusive description of parton emissions. Events generated in
this way provide a physical result across the entire jet transverse momentum
spectrum, have next-to-leading order normalization everywhere, and have
positive definite event weights. The method is generalizable without
modification to any color singlet production process.Comment: 13 pages, 9 figure
Exclusive W + photon production in proton-antiproton collisions I: general formalism
We present a detailed computation of the fully exclusive cross section of p +
antip --> W + photon + X with X = 0 and 1 jet in the framework of the
factorization theorem and dimensional regularization. Order alpha-strong and
photon bremsstrahlung contributions are discussed in the MS-bar mass
factorization scheme. The resulting expressions are ready to be implemented
numerically using Monte Carlo techniques to compute single and double
differential cross sections and correlations between outgoing pairs of
particles.Comment: ITP-SB-93-72, 40 pages, LateX. 3*4 figures in separate file.
([email protected]) ([email protected]
Complete Genome Sequences of Paenibacillus Larvae Phages BN12, Dragolir, Kiel007, Leyra, Likha, Pagassa, PBL1c, and Tadhana
We present here the complete genomes of eight phages that infect Paenibacillus larvae, the causative agent of American foulbrood in honeybees. Phage PBL1c was originally isolated in 1984 from a P. larvae lysogen, while the remaining phages were isolated in 2014 from bee debris, honeycomb, and lysogens from three states in the USA
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The interactive on-site inspection system: An information management system to support arms control inspections
The increasing use of on-site inspection (OSI) to meet the nation`s obligations with recently signed treaties requires the nation to manage a variety of inspection requirements. This document describes a prototype automated system to assist in the preparation and management of these inspections
The interactive on-site inspection system: An information management system to support arms control inspections
The increasing use of on-site inspection (OSI) to meet the nation`s obligations with recently signed treaties requires the nation to manage a variety of inspection requirements. This document describes a prototype automated system to assist in the preparation and management of these inspections
Applicability constraints of the Equivalence Theorem
In this work we study the applicability of the Equivalence Theorem, either
for unitary models or within an effective lagrangian approach. There are two
types of limitations: the existence of a validity energy window and the use of
the lowest order in the electroweak constants. For the first kind, we consider
some methods, based on dispersion theory or the large limit, that allow us
to extend the applicability. For the second, we have obtained numerical
estimates of the effect of neglecting higher orders in the perturbative
expansion.Comment: Final version to appear in Phys. Rev. D. Power counting and energy
range estimates have been refined, improved referencing. 4 postscript
figures, uses revtex. FT-UCM 1/9
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