Indian Institute of Technology Bombay

About: Indian Institute of Technology Bombay is a education organization based out in Mumbai, India. It is known for research contribution in the topics: Population & Thin film. The organization has 16756 authors who have published 33588 publications receiving 570559 citations.

Uncertainty modelling and limit state reliability of tunnel supports under seismic effects

Abstract: Underground openings and excavations are increasingly being used for civilian and strategic purposes all over the world. Recent earthquakes and resulting damage have brought into focus and raised the awareness for aseismic design and construction. In addition, underground tunnels, particularly, have distinct seismic behaviour due to their complete enclosure in soil or rock and their significant length. Therefore, seismic response of tunnel support systems warrant closer attention. The geological settings in which they are placed are often difficult to describe due to limited site investigation data and vast spatial variability. Therefore, the parameters which govern the design are many and their variabilities cannot be ignored. A solution to this issue is reliability based analysis and design. These real conditions of variability can only be addressed through a reliability based design. The problem addressed here is one of reliability-based analysis of the support system of an underground tunnel in soil. Issues like the description of the interaction between the tunnel lining and the surrounding medium, the type of limit state that would be appropriate, the nonavailability of a closed form performance function and the advantages of response surface method [RSM] are looked into. Both static and seismic environment with random variability in the material properties are studied here. Support seismic response is studied in terms of thrust, moment and shear forces in the lining. Interactive analysis using finite element method [FEM], combined with RSM and Hasofer-Lind reliability concept to assess the performance of the tunnel support, has proven useful under real field situations.

3D Shape Segmentation with Projective Convolutional Networks

Abstract: This paper introduces a deep architecture for segmenting 3D objects into their labeled semantic parts. Our architecture combines image-based Fully Convolutional Networks (FCNs) and surface-based Conditional Random Fields (CRFs) to yield coherent segmentations of 3D shapes. The image-based FCNs are used for efficient view-based reasoning about 3D object parts. Through a special projection layer, FCN outputs are effectively aggregated across multiple views and scales, then are projected onto the 3D object surfaces. Finally, a surface-based CRF combines the projected outputs with geometric consistency cues to yield coherent segmentations. The whole architecture (multi-view FCNs and CRF) is trained end-to-end. Our approach significantly outperforms the existing state-of-the-art methods in the currently largest segmentation benchmark (ShapeNet). Finally, we demonstrate promising segmentation results on noisy 3D shapes acquired from consumer-grade depth cameras.

Bulk Planar Junctionless Transistor (BPJLT): An Attractive Device Alternative for Scaling

Abstract: We propose a novel highly scalable source-drain-junction-free field-effect transistor that we call the bulk planar junctionless transistor (BPJLT). This builds upon the idea of an isolated ultrathin highly doped device layer of which volume is fully depleted in the off-state and is around flatband in the on-state. Here, the leakage current depends on the effective device layer thickness, and we show that with well doping and/or well bias, this can be controllably made less than the physical device layer thickness in a bulk planar junction-isolated structure. We demonstrate by extensive device simulations that these additional knobs for controlling short-channel effects reduce the off-state leakage current by orders of magnitude for similar on-state currents, making the BPJLT highly scalable.

Observation of D0 meson nuclear modifications in Au+Au collisions at sNN =200GeV

Abstract: We report the first measurement of charmed-hadron (D-0) production via the hadronic decay channel (D-0 -> K- + pi(+)) in Au + Au collisions at root(NN)-N-s = 200 GeV with the STAR experiment. The charm production cross section per nucleon- nucleon collision at midrapidity scales with the number of binary collisions, N-bin, from p + p to central Au + Au collisions. The D-0 meson yields in central Au + Au collisions are strongly suppressed compared to those in p + p scaled by N-bin, for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate p(T) is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.