515 research outputs found
Appearance-based indoor localization: a comparison of patch descriptor performance
Vision is one of the most important of the senses, and humans use it
extensively during navigation. We evaluated different types of image and video
frame descriptors that could be used to determine distinctive visual landmarks
for localizing a person based on what is seen by a camera that they carry. To
do this, we created a database containing over 3 km of video-sequences with
ground-truth in the form of distance travelled along different corridors. Using
this database, the accuracy of localization - both in terms of knowing which
route a user is on - and in terms of position along a certain route, can be
evaluated. For each type of descriptor, we also tested different techniques to
encode visual structure and to search between journeys to estimate a user's
position. The techniques include single-frame descriptors, those using
sequences of frames, and both colour and achromatic descriptors. We found that
single-frame indexing worked better within this particular dataset. This might
be because the motion of the person holding the camera makes the video too
dependent on individual steps and motions of one particular journey. Our
results suggest that appearance-based information could be an additional source
of navigational data indoors, augmenting that provided by, say, radio signal
strength indicators (RSSIs). Such visual information could be collected by
crowdsourcing low-resolution video feeds, allowing journeys made by different
users to be associated with each other, and location to be inferred without
requiring explicit mapping. This offers a complementary approach to methods
based on simultaneous localization and mapping (SLAM) algorithms.Comment: Accepted for publication on Pattern Recognition Letter
Quantum-mechanical calculation of Stark widths of Ne VII n=3, transitions
The Stark widths of the Ne VII 2s3s-2s3p singlet and triplet lines are
calculated in the impact approximation using quantum-mechanical Convergent
Close-Coupling and Coulomb-Born-Exchange approximations. It is shown that the
contribution from inelastic collisions to the line widths exceeds the elastic
width contribution by about an order of magnitude. Comparison with the line
widths measured in a hot dense plasma of a gas-liner pinch indicates a
significant difference which may be naturally explained by non-thermal Doppler
effects from persistent implosion velocities or turbulence developed during the
pinch implosion. Contributions to the line width from different partial waves
and types of interactions are discussed as well.Comment: 8 pages, 3 figures; accepted by Phys. Rev.
Electron-impact broadening of the 3s-3p lines in low-Z Li-like ions
The collisional electron-impact line widths of the 3s-3p transitions in
Li-like ions from B III to Ne VIII are calculated with the convergent
close-coupling (CCC) method from the atomic collision theory. The elastic and
inelastic contributions to the line broadening and their Z-scaling are
discussed in detail, and comparisons with recent experimental and theoretical
results are also presented. It is found that similar to our previous study of
line broadening in Be-like ions, the difference between experimental and CCC
results monotonically increases with the spectroscopic charge of an ion.Comment: 23 pages, 8 figures, 1 table. To be published in JQSR
The Effect of Fused 12-Membered Nickel Metallacrowns on DNA and their Antibacterial Activity
The synthesis, characterization and the biological study of a series of Ni(ll)2(carboxylato)2 [12-
MCNi(II)N(shi)2(pko)2-4][12-MCNi(ii)N(sh03(pko)-4] (CH3OH)3(H3O) fused 12-membered metallacrowns with 10 metal ions and commercial available herbicides or anti-inflammatory drugs as carboxylato ligands are
reported. All the compounds have a mixed ligand composition with salicylhydroxamic acid and di-2-pyridylketonoxime
as chelate agents. The compounds construct metallacrown cores {[12-MCNi(n)N(sj02(pko)2-4][12-MCNi(ll)N(shO3(pko)-4]}2+ following the pattern [-Ni-O-N-]4. The neutral decanuclear [Ni(II)(A)]2[12-MCNi(II)N(shi)2(pko)2-4][12-MCNi(II)N(pko)3(pko)-4] fused metallacrown, consists of two [12-MCM(ox)N(ligand)-4] units the {Ni(ll)(A)[12-MCNi(II)N(shi)2(pko)2-4]} and {Ni(II)(A)[12-MCNi(II)N(shi)3(pko)-4]} with 1+ and 1- charge, respectively. Each metallacrown unit has four ring Ni(II) ions and one additional encapsulated Ni(II) ion in planar arrangement. The anionic unit is bonded with cationic one creating binuclear moieties. The herbicide or antiiflammatory carboxylato ligands are bridging the central octahedral nickel atom with a ring metal ion
in a bindetate fashion. The effect on DNA and their antibacterial activity was examined. The changes in the
mobility can be attributed to the altered structures of the pDNA treated with Ni(II) complexes. Evaluating the
data of the antibacterial activity of the compounds tested, we can conclude that nickel complexes present
strong antibacterial activity
WTA/TLA: A UAV-captured dataset for semantic segmentation of energy infrastructure
Automated inspection of energy infrastructure with Unmanned Aerial Vehicles (UAVs) is becoming increasingly important, exhibiting significant advantages over manual inspection, including improved scalability, cost/time effectiveness, and risks reduction. Although recent technological advancements enabled the collection of an abundance of vision data from UAVs’ sensors, significant efforts are still required from experts to interpret manually the collected data and assess the condition of energy infrastructure. Thus, semantic understanding of vision data collected from UAVs during inspection is a critical prerequisite for performing autonomous robotic tasks. However, the lack of labeled data introduces challenges and limitations in evaluating the performance of semantic prediction algorithms. To this end, we release two novel semantic datasets (WTA and TLA) of aerial images captured from power transmission networks and wind turbine farms, collected during real inspection scenarios with UAVs. We also propose modifications to existing state-of-the-art semantic segmentation CNNs to achieve improved trade-off between accuracy and computational complexity. Qualitative and quantitative experiments demonstrate both the challenging properties of the provided dataset and the effectiveness of the proposed networks in this domain.The dataset is available at: https://github.com/gzamps/wta_tla_dataset
Stark Broadening of the B III 2s-2p Lines
We present a quantum-mechanical calculation of Stark line widths from
electron-ion collisions for the , lambda = 2066 and 2067
A, resonance transitions in B III. The results confirm the previous
quantum-mechanical R-matrix calculations but contradict recent measurements and
semi-classical and some semi-empirical calculations. The differences between
the calculations can be attributed to the dominance of small L partial waves in
the electron-atom scattering, while the large Stark widths inferred from the
measurements would be substantially reduced if allowance is made for
hydrodynamic turbulence from high Reynolds number flows and the associated
Doppler broadening.Comment: 21 pages, 4 figures; to be published in Phys. Rev.
Magnetization of polydisperse colloidal ferrofluids: Effect of magnetostriction
We exploit magnetostriction in polydisperse ferrofluids in order to generate
nonlinear responses, and apply a thermodynamical method to derive the desired
nonlinear magnetic susceptibility. For an ideal gas, this method has been
demonstrated to be in excellent agreement with a statistical method. In the
presence of a sinusoidal ac magnetic field, the magnetization of the
polydisperse ferrofluid contains higher-order harmonics, which can be extracted
analytically by using a perturbation approach. We find that the harmonics are
sensitive to the particle distribution and the degree of field-induced
anisotropy of the system. In addition, we find that the magnetization is higher
in the polydisperse system than in the monodisperse one, as also found by a
recent Monte Carlo simulation. Thus, it seems possible to detect the size
distribution in a polydisperse ferrofluid by measuring the harmonics of the
magnetization under the influence of magnetostriction.Comment: 23 pages, 4 figures. To be accepted for publication in Phys. Rev.
Anti-C1q Autoantibodies Are Frequently Detected in Patients With Systemic Sclerosis Associated With Pulmonary Fibrosis
BACKGROUND: Anti-C1q autoantibodies (autoAbs) are associated with systemic lupus erythematosus (SLE) but their presence in other rheumatic diseases has not been adequately investigated.
OBJECTIVE: We aim to assessanti-C1q autoAbs and circulating immune complexes (CICs) in systemic sclerosis (SSc).
METHODS: One hundred twenty four patients with SSc (106 females; median age 59.4 years, range 25-81.4; 75(60.5%) with limited cutaneous SSc[lcSSc], and 49(39.5%) with diffuse cutaneous SSc[dcSSc]), were studied. Twenty-five patients with Sjögren\u27s syndrome (SjS), 29 with rheumatoid arthritis (RA), and 38 patients with systemic lupus erythematosus (SLE) and 53 healthy controls (NC) were also included. ELISAs with high and low salt buffers the former allowing IgGFc binding to C1q, the latter not allowing IgGFc binding and anti-C1q Ab binding to C1q were used to measure anti-C1q Abs and CICs.
RESULTS: Anti-C1q Abs were present in20/124 (16.1%) SSc patients [5 had high levels (\u3e80 RU/mL) and 10 patients (50%) had moderate levels (40-80 RU/mL)] compared to 1/25 (4%) SjS, 1/29 (3.4%) RA patients (p
CONCLUSIONS: Anti-C1q autoAbs were frequently detected in patients with SSc and their high levels predict the co-occurrence of pulmonary fibrosis or pulmonary arterial hypertension
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