1,945 research outputs found

    Can i teach a robot to replicate a line art

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    Line art is arguably one of the fundamental and versatile modes of expression. We propose a pipeline for a robot to look at a grayscale line art and redraw it. The key novel elements of our pipeline are: a) we propose a novel task of mimicking line drawings, b) to solve the pipeline we modify the Quick-draw dataset to obtain supervised training for converting a line drawing into a series of strokes c) we propose a multi-stage segmentation and graph interpretation pipeline for solving the problem. The resultant method has also been deployed on a CNC plotter as well as a robotic arm. We have trained several variations of the proposed methods and evaluate these on a dataset obtained from Quick-draw. Through the best methods we observe an accuracy of around 98% for this task, which is a significant improvement over the baseline architecture we adapted from. This therefore allows for deployment of the method on robots for replicating line art in a reliable manner. We also show that while the rule-based vectorization methods do suffice for simple drawings, it fails for more complicated sketches, unlike our method which generalizes well to more complicated distributions.Comment: 9 pages, Accepted for the 2020 Winter Conference on Applications of Computer Vision (WACV '20); Supplementary Video: https://youtu.be/nMt5Dw04Xh

    Another shock for the Bullet cluster, and the source of seed electrons for radio relics

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    With Australia Telescope Compact Array observations, we detect a highly elongated Mpc-scale diffuse radio source on the eastern periphery of the Bullet cluster 1E0657-55.8, which we argue has the positional, spectral and polarimetric characteristics of a radio relic. This powerful relic (2.3+/-0.1 x 10^25 W Hz^-1) consists of a bright northern bulb and a faint linear tail. The bulb emits 94% of the observed radio flux and has the highest surface brightness of any known relic. Exactly coincident with the linear tail we find a sharp X-ray surface brightness edge in the deep Chandra image of the cluster -- a signature of a shock front in the hot intracluster medium (ICM), located on the opposite side of the cluster to the famous bow shock. This new example of an X-ray shock coincident with a relic further supports the hypothesis that shocks in the outer regions of clusters can form relics via diffusive shock (re-)acceleration. Intriguingly, our new relic suggests that seed electrons for reacceleration are coming from a local remnant of a radio galaxy, which we are lucky to catch before its complete disruption. If this scenario, in which a relic forms when a shock crosses a well-defined region of the ICM polluted with aged relativistic plasma -- as opposed to the usual assumption that seeds are uniformly mixed in the ICM -- is also the case for other relics, this may explain a number of peculiar properties of peripheral relics.Comment: 10 pages, 9 figures, 1 table, accepted for publication in MNRA

    Cruciate retaining versus posterior-stabilized total knee arthroplasty: a short-term comparative study

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    Background: Total knee arthroplasty has got excellent results. Among the techniques (posterior-stabilized vs posterior cruciate retaining total knee arthroplasty) it is unclear whether one design has superior outcome over another. The purpose of the present study was to directly compare clinical and radiological outcomes of these two designs.Methods: A prospective study involving 36 patients who received a cruciate-retaining implant were compared to 30 patients who received posterior-stabilized prosthesis. At 3 months follow-up time clinical and radiological evaluation done and results were analyzed.Results: At 3 months follow-up time mean knee society scores improved from 49.9/46.9 (objective/subjective score) points to 80.9/82.5 points in the cruciate-retaining group and from 48.2/43 (objective/subjective score) points to 80.4/80.2 points in the posterior-stabilized group. The ranges of motion was 117.2° (range, 90° to 130°) and 125.3° (range, 100° to 140°) in the cruciate-retaining and posterior-stabilized group respectively, at 3 month follow-up. One patient had post-operatively periprosthetic fracture reported after 2 weeks (treated conservatively), one had superficial infection (treated with dressing) and one patient with superfical infection required debridement.Conclusions: This study did not conclusively demonstrate the superiority of one knee design over the other, suggesting that the choice of implant should be based on surgeon preference, patients knee dimensions, pre-op knee deformity and existing pathology of the posterior cruciate ligament

    Improved Thermoelectric Cooling Based on the Thomson Effect

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    Traditional thermoelectric Peltier coolers exhibit a cooling limit which is primarily determined by the figure of merit, zT. Rather than a fundamental thermodynamic limit, this bound can be traced to the difficulty of maintaining thermoelectric compatibility. Self-compatibility locally maximizes the cooler's coefficient of performance for a given zT and can be achieved by adjusting the relative ratio of the thermoelectric transport properties that make up zT. In this study, we investigate the theoretical performance of thermoelectric coolers that maintain self-compatibility across the device. We find such a device behaves very differently from a Peltier cooler, and term self-compatible coolers "Thomson coolers" when the Fourier heat divergence is dominated by the Thomson, as opposed to the Joule, term. A Thomson cooler requires an exponentially rising Seebeck coefficient with increasing temperature, while traditional Peltier coolers, such as those used commercially, have comparatively minimal change in Seebeck coefficient with temperature. When reasonable material property bounds are placed on the thermoelectric leg, the Thomson cooler is predicted to achieve approximately twice the maximum temperature drop of a traditional Peltier cooler with equivalent figure of merit (zT). We anticipate the development of Thomson coolers will ultimately lead to solid state cooling to cryogenic temperatures.Comment: The Manuscript has been revised for publication in PR

    PERFORMANCE AND A NEW 2-D ANALYTICAL MODELING OF A DUAL-HALO DUAL-DIELECTRIC TRIPLE-MATERIAL SURROUNDING-GATE-ALL-AROUND (DH-DD-TM-SGAA) MOSFET

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    This proposed work covers the effect of dual halo structure with dual dielectric. A 2-D analytical model for potential distribution, threshold voltage, electric field and sub-threshold swing has been described through the Poisson’s equation solution for a novel structure known as dual-halo dual-dielectric triple-material surrounding-gate MOSFET to diminish short channel effects. The new device has been incorporated with Dual halo near the source and drain sides, while the electrode at the gate incorporates three dissimilar work function metals. A relative estimation of short channel effects (SCEs) for DHDD-TM-SG, triple-material surrounding-gate (TM-SG) and single-halo triplematerial surrounding-gate (SH-TM-SG) MOSFETs has also been carried out in terms of threshold-voltage-roll-off, drain induced barrier lowering, hot carrier effects, and also sub-threshold swing. The proposed novel structure significantly reduces the SCEs. Therefore, DH-DD-TM-SG MOSFETs have superior performance than TM-SG and SH-TM-SG MOSFETs. The efficiency of the Dual halo-doped device is investigated. The proposed model demonstrates its validity by a comparing the simulated results from already published devices obtained by using TCAD Silvaco

    Monitoring airway mucus flow and ciliary activity with optical coherence tomography

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    Muco-ciliary transport in the human airway is a crucial defense mechanism for removing inhaled pathogens. Optical coherence tomography (OCT) is well-suited to monitor functional dynamics of cilia and mucus on the airway epithelium. Here we demonstrate several OCT-based methods upon an actively transporting in vitro bronchial epithelial model and ex vivo mouse trachea. We show quantitative flow imaging of optically turbid mucus, semi-quantitative analysis of the ciliary beat frequency, and functional imaging of the periciliary layer. These may translate to clinical methods for endoscopic monitoring of muco-ciliary transport in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD)

    Small Quadrupole Deformation for the Dipole Bands in 112In

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    High spin states in 112^{112}In were investigated using 100^{100}Mo(16^{16}O, p3n) reaction at 80 MeV. The excited level have been observed up to 5.6 MeV excitation energy and spin \sim 20\hbar with the level scheme showing three dipole bands. The polarization and lifetime measurements were carried out for the dipole bands. Tilted axis cranking model calculations were performed for different quasi-particle configurations of this doubly odd nucleus. Comparison of the calculations of the model with the B(M1) transition strengths of the positive and negative parity bands firmly established their configurations.Comment: 10 pages, 11 figures, 2 table

    Imaging three-dimensional rotational diffusion of plasmon resonant gold nanorods using polarization-sensitive optical coherence tomography

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    We demonstrate depth-resolved viscosity measurements within a single object using polarized optical scattering from ensembles of freely tumbling plasmon resonant gold nanorods (GNRs) monitored with polarization-sensitive optical coherence tomography. The rotational diffusion coefficient of the GNRs is shown to correlate with viscosity in molecular fluids according to the Stokes-Einstein relation. The plasmon resonant and highly anisotropic properties of GNRs are favorable for microrheological studies of nanoscale properties
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