Ellis–Bronnikov (EB) wormholes require violation of null energy conditions at the ‘throat’. This problem was cured by a simple modification of the ‘shape function’, which introduces a new parameter
m
...≥
2
(
m
=
2
corresponds to the EB model). This leads to a generalised (GEB) version. In this work, we consider a model where the GEB wormhole geometry is embedded in a five dimensional warped background. We studied the status of all the energy conditions in detail for both EB and GEB embedding. We present our results analytically (wherever possible) and graphically. Remarkably, the presence of decaying warp factor leads to satisfaction of weak energy conditions even for the EB geometry, while the status of all the other energy conditions are improved compared to the four dimensional scenario. Besides inventing a new way to avoid the presence of exotic matter, in order to form a wormhole passage, our work reveals yet another advantage of having a warped extra dimension.
Energy momentum tensor of a conformally coupled quantum scalar field in five dimensional warped cosmological spacetimes is studied. We look at situations where the four dimensional part represents a ...cosmological thick brane and the scale of the extra dimension is time dependent. Renormalization of the components of the energy momentum tensor is achieved using adiabatic regularization method. The resulting energy and pressure densities explicitly show the effects of warping and the dynamic extra dimension on the created matter. We discussed how the created matter may accumulate to form thick branes along the extra dimension.
We study the particle trajectories in the recently proposed five dimensional warped (generalized) Ellis–Bronnikov spacetime (5D-WGEB) (which does not require exotic matter) as well as it’s four ...dimensional counterpart (4D-GEB) in detail and conduct a comparative study. Analytical approach provides conditions which determines three types of trajectories (trapped, returning and crossing) for both 4D and 5D spacetimes. Notably in 5D geometry existence of trapped trajectories become highly sensitive to the initial conditions. We have solved the timelike geodesic equations numerically and presented the trajectories graphically along with corresponding geodesic potentials. We thus distinguished the roles of the so-called wormhole parameter and the warping factor regarding their effects on the trajectories and embedding as such. Interestingly, the 5D-WGEB model shows the localization of massive particles around the location of the brane for growing warp factor and runaway trajectories for decaying warp factor.
•Images use visual and scene text to convey ideas.•Jointly leveraging scene text and visual cues leads to robust semantic interpretation.•Contextual encoding capture dynamics between co-occurring ...visual and text elements.•Text visual semantics can be applied to retrieval and classification tasks alike.
Images with visual and scene text content are ubiquitous in everyday life. However, current image interpretation systems are mostly limited to using only the visual features, neglecting to leverage the scene text content. In this paper, we propose to jointly use scene text and visual channels for robust semantic interpretation of images. We not only extract and encode visual and scene text cues but also model their interplay to generate a contextual joint embedding with richer semantics. The contextual embedding thus generated is applied to retrieval and classification tasks on multimedia images with scene text content to demonstrate its effectiveness. In the retrieval framework, we augment the contextual semantic representation with scene text cues to mitigate vocabulary misses that may have occurred during the semantic embedding. To deal with irrelevant or erroneous scene text recognition, we also apply query-based attention to the text channel. We show that our multi-channel approach, involving contextual semantics and scene text, improves upon the absolute accuracy of the current state-of-the-art methods on Advertisement Images Dataset by 8.9% in the relevant statement retrieval task and by 5% in the topic classification task.
Palladium‐catalyzed cascade cyclization received much attention in organic synthesis due to its efficiency and rapid transformation of simple starting materials into complex molecular skeletons. ...Celebrating the 10th year of the prestigious Nobel prize for palladium chemistry, we witness it still proceeds strong over other transition metals for its versatility. Cascade reactions in contemporary organic synthesis reduced cost and time through careful design. It has emerged as the first choice, a powerful tool for multiple bond formations in one step with a wide range of functional group tolerance due to the deep understanding of various pathways. A variety of compounds with biological relevance with complex molecular scaffolds have been achieved using these cascade coupling reactions. This review outlines Pd‐catalyzed cascade reactions from the post‐Nobel era. Nevertheless, more discoveries and endless possibilities for new transformations are underway.
Celebrating the tenth year of the prestigious Nobel prize in 2010 for palladium chemistry; still, palladium stands strong over other transition metals for its versatility. Cascade reactions in contemporary organic synthesis reduced cost and time through careful design. This review outlines Pd‐catalyzed cascade reactions in organic synthesis from the post‐Nobel era.
To interact with its environment, a robot working in 3D space needs to organise its visual input in terms of objects or their perceptual precursors, proto-objects. Among other visual cues, depth is a ...submodality used to direct attention to visual features and objects. Current depth-based proto-object attention models have been implemented for standard RGB-D cameras that produce synchronous frames. In contrast, event cameras are neuromorphic sensors that loosely mimic the function of the human retina by asynchronously encoding per-pixel brightness changes at very high temporal resolution, thereby providing advantages like high dynamic range, efficiency (thanks to their high degree of signal compression), and low latency. We propose a bio-inspired bottom-up attention model that exploits event-driven sensing to generate depth-based saliency maps that allow a robot to interact with complex visual input. We use event-cameras mounted in the eyes of the iCub humanoid robot to directly extract edge, disparity and motion information. Real-world experiments demonstrate that our system robustly selects salient objects near the robot in the presence of clutter and dynamic scene changes, for the benefit of downstream applications like object segmentation, tracking and robot interaction with external objects.
Event cameras are bio‐inspired sensors that offer advantages over traditional cameras. They operate asynchronously, sampling the scene at microsecond resolution and producing a stream of brightness ...changes. This unconventional output has sparked novel computer vision methods to unlock the camera's potential. Here, the problem of event‐based stereo 3D reconstruction for SLAM is considered. Most event‐based stereo methods attempt to exploit the high temporal resolution of the camera and the simultaneity of events across cameras to establish matches and estimate depth. By contrast, this work investigates how to estimate depth without explicit data association by fusing disparity space images (DSIs) originated in efficient monocular methods. Fusion theory is developed and applied to design multi‐camera 3D reconstruction algorithms that produce state‐of‐the‐art results, as confirmed by comparisons with four baseline methods and tests on a variety of available datasets.
Event cameras are novel bioinspired sensors offering advantages over traditional cameras. They mimic human eyes, naturally responding to moving patterns in the scene asynchronously. How can a robot with two or more event‐camera eyes map its 3D environment? A stereo correspondence‐free approach that fuses volumetric event‐data representations early in the system is presented: https://github.com/tub-rip/dvs_mcemvs
Split dynamics of the liquid–liquid two-phase mixture through horizontal T-junction is numerically investigated by varying the parameters like inlet-volume-fraction, inlet-mixture-velocity, liquid ...pair, and conduit-diameter. Ultimately, the effects of these parameters on the said dynamics are extracted. 3D steady-state numerical solutions are achieved by adopting a Finite Volume-based Eulerian Multi-Fluid VOF model. To simulate the turbulence, SST
k
–
w
model is used. Before producing the results, the adopted numerical methodology is successfully validated with the results available in the literature. Composition of the liquid–liquid two-phase mixture obtained along the branch and run arms differ from that along inlet arm. Again, that composition along the branch and run arm are also different from each other. Inertia imbalance is found as the most vital factor to influence the dynamics of phase split. More split is obtained for the mixture with high density-difference between the component liquids. No significant phase split is found for a liquid pair when any one of them has high viscosity. Depending on the conduit-diameter, liquid pair, and inlet-mixture-velocity, a critical inlet-volume-fraction (> 0.5) is found where no split occurs, and the phenomenon of phase split is reversed at the critical inlet-volume-fraction. As the inlet-velocity increases, critical inlet-volume-fraction increases for T-junction having a smaller conduit-diameter, but it increases very slowly for a larger conduit-diameter. With the increment in inlet-velocity, effective phase split reduces for smaller conduit-diameter, and it slightly increases for a larger conduit-diameter. The intensity of the split decreases with the increment in conduit-diameter. Larger critical inlet-volume-fraction is found for a larger conduit-diameter.
* Trees are the main sources of paper production, in most of the cases, as far as the intellectual usages are concerned. However, our planet is lacking in that particular natural resource due to ...rapid growth of population, urbanization, and increased pollution, more importantly non-judicial utilization of such kind. Indian education sectors (schools, colleges, universities) utilize a major part in consumption of papers as a classical practice for conducting examinations and other documentation activities. Our attempt in this article is to investigate and provide an optimal estimate of the number of pages actually required in answer booklet in higher education sector. Truncated Poisson distribution is found to be the best fit for the data on number of pages left blank in an answer booklet after conduction of semester end examinations. To predict the outcome based on various factors such as, lines per pages, words per line, types of examinations etc. suitable regression modelling is performed. A real data set, collected over a period of one month, is been analysed to illustrate the methods and conclusion is accomplished in the direction of cost reduction, saving of papers, and in turn, logical uses of natural resource to protect environmental interests. Keywords: * truncated Poisson distribution; maximum likelihood estimation; utility function; environment protection.
The geometry of the 2-lobe rotors of a roots blower is proposed by the combination of three arcs and is parameterized by two independent variables. By considering a standard combination of these ...variables, attempts are made to grasp the unsteady interior flow phenomena and thermal interaction in the blower as well as to comprehend the effect of main influencing factors on the performance of the blower using a transient finite volume-based dynamic-mesh-rearrangement method. A grid-independent test is conducted, and the adopted methodology is validated. At first, an endeavor is made to realize the transient internal flow field and heat interaction within the roots blower. Then, individual efforts are made to apprehend the effect of rotor speed, discharge pressure, and clearance size (provided in between the rotors or in between the rotors and casing) on the said transient flow dynamics and heat interaction. Time variation of the discharge velocity, mass flowrate, and discharge temperature are found to be fluctuating in nature. Pressure, velocity, and temperature distributions in the blower, as well as the leakages, backflow, vortices in the blower, etc., at different moments, are found to be strongly dependent on the rotor speed, discharge pressure, clearance size between the rotors or between the rotor and housing. The nature and amplitude of the time variation of exhaust velocity, discharge mass flowrate, outlet-temperature, and the blower performance are also found to be very much sensitive to the chosen rotor speed, discharge pressure, and clearance size.
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