Understanding the Perceived Quality of Video Predictions

The study of video prediction models is believed to be a fundamental approach to representation learning for videos. While a plethora of generative models for predicting the future frame pixel values given the past few frames exist, the quantitative evaluation of the predicted frames has been found to be extremely challenging. In this context, we study the problem of quality assessment of predicted videos. We create the Indian Institute of Science Predicted Videos Quality Assessment (IISc PVQA) Database consisting of 300 videos, obtained by applying different prediction models on different datasets, and accompanying human opinion scores. We collected subjective ratings of quality from 50 human participants for these videos. Our subjective study reveals that human observers were highly consistent in their judgments of quality of predicted videos. We benchmark several popularly used measures for evaluating video prediction and show that they do not adequately correlate with these subjective scores. We introduce two new features to effectively capture the quality of predicted videos, motion-compensated cosine similarities of deep features of predicted frames with past frames, and deep features extracted from rescaled frame differences. We show that our feature design leads to state of the art quality prediction in accordance with human judgments on our IISc PVQA Database. The database and code are publicly available on our project website: https://nagabhushansn95.github.io/publications/2020/pvqaComment: Project website: https://nagabhushansn95.github.io/publications/2020/pvqa.htm

Factors Impacting Leaflet Coaptation and Durability in Prosthetic Heart Valves

The treatment of Aortic regurgitation using TAVR has not met with excellent outcomes that TAVR did with Aortic stenosis treatment due to differences in patient anatomies, and manifestation of the disease at the native valve annulus. With exception of JenaValve device which relies on proprietary clipping mechanism to anchor the valve, off-label use of TAVR devices that are otherwise indicated for use only to treat AS disease, relied on valve-in-valve for anchoring to prevent paravalvular leakage and valve embolization. The under-expansion of the inside valve due to stiffness and geometry of the outside valve has an impact on leaflet coaptation leading to additional stresses on the leaflets and decreased durability. This article explores the stent frame and leaflet design considerations and their impact on valve durability in AR patient anatomies that rely predominantly on valve-in-valve configuration for anchoring

Flexure compensation simulation tool for TMT-WFOS Spectrograph

The Wide Field Optical Spectrograph (WFOS) is one of the first-light instruments of Thirty Meter Telescope. It is a medium resolution, multi object, wide field optical spectrograph. Since 2005 the conceptual design of the instrument has focused on a slit-mask based, grating exchange design that will be mounted at the Nasmyth focus of TMT. Based on the experience with ESI, MOSFIRE and DEIMOS for Keck we know flexure related image motion will be a major problem with such a spectrograph and a compensation system is required to mitigate these effects. We have developed a flexure Compensation and Simulation (FCS) tool for TMT-WFOS that provides an interface to accurately simulate the effects of instrument flexure at the WFOS detector plane (e.g image shifts) using perturbation of key optical elements and also derive corrective motions to compensate the image shifts caused by instrument flexure. We are currently using the tool to do mote-carlo simulations to validate the optical design of a slit-mask concept we call Xchange-WFOS, and to optimize the flexure compensation strategy. We intend to use the tool later in the design process to predict the actual flexure by replacing the randomized inputs with the signed displacement and rotations of each element predicted by global FEA model on the instrument

Identifying the population of T-Tauri stars in Taurus: UV-optical synergy

With the third data release of the Gaia mission $Gaia$ DR3 with its precise photometry and astrometry, it is now possible to study the behaviour of stars at a scale never seen before. In this paper, we developed new criteria to identify T-Tauri stars (TTS) candidates using UV and optical CMDs by combining the GALEX and Gaia surveys. We found 19 TTS candidates and 5 of them are newly identified TTS in the Taurus Molecular Cloud (TMC), not catalogued before as TMC members. For some of the TTS candidates, we also obtained optical spectra from several Indian telescopes. We also present the analysis of the distance and proper motion of young stars in the Taurus using data from $Gaia$ DR3. We found that the stars in Taurus show a bimodal distribution with distance, having peaks at $130.17_{-1.24}^{1.31}$ pc and $156.25_{-5.00}^{1.86}$ pc. The reason for this bimodality, we think, is due to the fact that different clouds in the TMC region are at different distances. We further show that the two populations have similar ages and proper motion distribution. Using the $Gaia$ DR3 colour-magnitude diagram, we show that the age of Taurus is consistent with 1 Myr.Comment: 13 pages, 10 figure

Atmospheric dispersion corrector for a multi-object spectroscopic mode of HROS-TMT

Highly multiplexed spectroscopic surveys have changed the astronomy landscape in recent years. However, these surveys are limited to low and medium spectral resolution. High spectral resolution spectroscopy is often photon starved and will benefit from a large telescope aperture. Multiplexed high-resolution surveys require a wide field of view and a large aperture for a suitable large number of bright targets. This requirement introduces several practical difficulties, especially for large telescopes, such as the future ELTs. Some of the challenges are the need for a wide field atmospheric dispersion corrector and to deal with the curved non-telecentric focal plane. Here, we present a concept of Multi-Object Spectroscopy (MOS) mode for TMT High-Resolution Optical Spectrograph (HROS), we have designed an atmospheric dispersion corrector for individual objects that fit inside a fiber positioner. We present the ZEMAX design and the performance of the atmospheric dispersion corrector for all elevations accessible by TMT

Morphometric Study of Pterion in Dry Human Skull at Medical College of Eastern Nepal

Introduction: The pterion is defined as an H shaped sutural confluence present on the lateral side of the skull. This pterion junction has been used as a common extra-cranial landmark for surgeons in microsurgical and surgical approaches towards important pathologies of this region. Methods: This is an analytical cross-sectional study conducted at the Department of Anatomy, Birat Medical College & Teaching Hospital, Tankisinuwari, Morang, Nepal. Total enumeration technique was used to collect samples where 31 dry human skulls of unknown age and sex were taken. The sutural pattern and location of the pterion were determined and measured on both sides of each skull using a digital vernier caliper.  Results: Three types of sutural patterns of pterion were observed. Among them, the Sphenoparietal type was higher in frequency. The frequency was 26 (83.8%) on the right side and 24 (77.4%) on the left side. The distance between the center of pterion to the midpoint of the upper border of the zygomatic arch was 3.82±0.3 cm on the right side and 3.8±0.29 cm on the left side. The distance between the center of pterion to the postero-lateral aspect of fronto-zygomatic suture was 3.02±0.23 cm on the right side and 3.0±0.23 cm on the left side. Conclusion: The information of the sutural pattern and the location of the pterion from the different bony landmarks of our study may be useful for anthropologists and neurosurgeons.   Keywords: Frontozygomatic suture, Morphometric, Pterion, zygomatic arch DOI: https://doi.org/10.3126/jkahs.v2i3.2665